NeuroNews issue 43 – US

September 2021 | Issue 43

www.neuronewsinternational.com

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Featured in this issue:

Jeffrey Saver Ethical challenges in remote stroke interventions

Profile Else Charlotte Sandset

Neuromodulation:

page 14

page 19

“Welcome and exciting”: Evidence mounts in favour of flow diversion technologies

assessment and comparative effectiveness analysis. The good news is that patients have many options. Physicians and surgeons must help patients select the best strategies to address their unique situations based on best medical and scientific evidence.”

The use of flow diverter devices to treat intracranial aneurysms dates back roughly a full decade to the US Food and Drug Administration (FDA) granting Covidien premarket approval for its Pipeline embolisation device (PED) in 2011—a company and, therefore, a technology, that has since been acquired by Medtronic. This has made Medtronic and the PED frontrunners in the field, and fresh evidence on this device is still emerging 10 years on, with data on 1,000 aneurysms from a single-centre registry, published in Neurosurgery in June 2021, concluding that it is safe and effective at up to 13 years of follow-up.

Multiple pieces of clinical research supporting And, even in the short window of time since these the use of flow diverter devices to treat results were published, key data on other intracranial aneurysms have come to flow diverter products have been light so far in 2021. In the past few weeks presented to the neurointervention alone, data from a multicentre pivotal trial world. This year’s SNIS annual Five-year assessing the Flow redirection endoluminal meeting saw Alexander L Coon results from (director of Cerebrovascular & device (FRED; MicroVention/Terumo) stent system have been published in the Journal Neurosurgery, SCENT trial= Endovascular of NeuroInterventional Surgery (JNIS), Carondelet Neurological while five-year results from the SCENT Institute, St Joseph’s Hospital, (Surpass intracranial aneurysm embolisation Tucson, USA) present five-year system pivotal trial to treat large or results from the SCENT giant wide-neck aneurysms; Stryker trial of the Surpass Neurovascular) study were presented Streamline device—the at the Society of NeuroInterventional largest prospective flow Surgery’s 18th annual meeting (SNIS; diversion study in this 26–29 July 2021, Colorado Springs, space to date, he claimed.

USA and virtual).

This trial, which was set up to evaluate the incidence frequency of he growing body of evidence in favour safety and effectiveness of aneurysm unchanged or of using flow diversion technologies for of Stryker’s device retreatment improved reported functional this indication—and the emergence of for the endovascular outcomes several different devices in this space in recent treatment of patients times—is a “welcome and exciting development”, with unruptured large or according to Philip M Meyers of the Neurointervention giant intracranial aneurysms Clinic at St Luke’s Health System in Boise, USA, who of the internal carotid artery (ICA) to the is also past president of SNIS and editor-in-chief of ICA terminus, involved 180 patients NeuroNews. from 26 centres in the USA. Coon “There have been numerous important publications noted in his late-breaking abstract in the neurointerventional space over the past year,” presentation that the SCENT trial Philip M he adds. “Tremendous growth in applications of new Meyers techniques and devices requires ongoing technology Continued on page 2

2.8%

80.7%

T

Special edition Spinal cord stimulation innovations and insights

Study indicates clinical benefit of non-paraesthesiabased approaches in burst SCS lead placement A study published in Neuromodulation: Technology at the Neural Interface has found that equivalent clinical benefits can be achieved in lead placement for burst spinal cord stimulation (SCS) using either conventional paraesthesia mapping, or anatomic landmarkbased approaches, in patients with chronic low back pain.

IN REPORTING THE ONE-YEAR safety and efficacy results from the CRISP (Comparison of paraesthesia mapping to anatomic midline-based burst programming strategies) study, Adnan Al-Kaisy (Pain & Neuromodulation Academic Research Centre, Guy’s & St Thomas’ NHS Foundation Trust, London, UK) and colleagues write: “The results exhibit the feasibility of anatomic placement as a procedure that can potentially establish a more streamlined and time-efficient treatment continuum with minimal patient discomfort.

“Also, physicians could have the option to choose the most appropriate lead implantation strategy to suit their patient’s characteristics when employing the burst SCS modality. This study can serve as a fundamental knowledge Continued on page 19

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September 2021 | Issue 43

Flow Diverters

“Welcome and exciting”: Evidence mounts in favour of flow diversion technologies Continued from page 1

met its primary safety and efficacy endpoints at 12 months, and these data were used to support FDA investigational device exemption (IDE) premarket approval of the Surpass Streamline flow diverter in 2018.

Moving on to discuss the five-year safety outcomes from the trial, Coon stated that the number of neurological deaths did not increase from 12 months through 60 months—with one new case being reported after 60 months—before adding that there were just three cases of new or worsening major ipsilateral stroke from 12 months through 60 months, and no additional late aneurysm ruptures over this period.

Regarding five-year angiographic effectiveness, he reported a 90.2% rate of complete aneurysm occlusion, a 1.4% rate of implant stenosis (≥50%) and a 2.9% rate of parent artery stenosis (≥50%) at 60 months, in addition to a “very low” incidence of aneurysm retreatment (2.8%, n=5), and an 80.7% frequency of patients reporting unchanged or improved functional outcome scores compared to baseline.

He concluded that the long-term secondary safety and effectiveness results demonstrated consistency with 12-month primary safety and effectiveness results from the SCENT trial, asserting that “these findings reinforce the benefit of minimising the risk of aneurysm rupture following Alexander L treatment of aneurysms greater than or Coon equal to 10mm in size with the Surpass Streamline flow diverter—supported by high occlusion rates and low rates of delayed adverse events”.

Discussing the wider implications of these findings, Meyers says: “Long-term evidence is very important, because many devices and their applications in neurointervention are relatively new. Short-term data demonstrate safety and efficacy but, for diseases with lifetime risk, longer term information helps to answer important questions for patients and caregivers alike.”

The other piece of major evidence on flow diversion technology seen recently—results from the US pivotal trial of FRED system—has been published in JNIS by Cameron G McDougall (director of Endovascular Neurosurgery, Johns Hopkins Hospital, Baltimore, USA) et al. “Although the FRED system is a relative newcomer to the flow diversion field, a growing body of high-quality evidence consistently shows it provides satisfactory safety and efficacy results,” the authors note in their report.

In this multicentre, prospective, single-arm, IDE clinical study, a total of 145 patients with aneurysms of unfavourable morphology for traditional endovascular therapies— including large, wide-necked and fusiform aneurysms—were enrolled across 23 centres, and underwent Cameron G McDougall attempted placement of the FRED stent system. After one year of follow-up, nine patients (6.2%) met the composite primary safety endpoint of major stroke or death within 30 days, or major ipsilateral stroke or neurological death after 30 days.

Further, regarding effectiveness, 80 of 139 patients (57.6%) with angiograms interpretable at follow-up met the criteria for primary effectiveness—that being complete aneurysm occlusion without stenosis >50%, and no retreatment.

McDougall et al conclude, therefore, that the FRED system is safe and effective for the treatment of intracranial aneurysms—and note that, on this basis, it was granted premarket approval by the FDA in January 2020. They also highlight that “very low” rates of disabling stroke or death seen here are “reassuring”, as they have been consistently reflected in other trials of the device. This trial and others involving the FRED system have reported “improving rates of complete aneurysm occlusion over time”, they add—a trend also observed in studies of PED. Recently, French medical technology firm Balt has emerged as the newest key player in the flow diversion sphere. Having received a CE mark in mid-2020, its Silk Vista device has been the subject of two academic papers this year—one in JNIS detailing the first multicentre experience using it in intracranial aneurysms, and another outlining safety outcomes in a short-term, observational study, which was published in Frontiers in Neurology.

While this newer innovation is yet to obtain the same bulk of clinical evidence as PED and Surpass, Meyers believes even these early findings contribute to the growing positivity surrounding flow diversion techniques right now.

“Proliferation in new neurointervention technologies is a welcome and exciting development,” Meyers states.

“The pace of innovation is accelerating, which should lead to progress including better, safer, more effective and more efficient devices. However, with that comes the responsibility to define the most appropriate indications and applications for each. This makes critical reasoning and data collection even more important. The number of patients with certain cerebrovascular diseases is limited— and we must work collectively to maximise the cultivation of useful knowledge.

“Advancement in flow diversion technologies is already underway,” he continues. “Bioactive coatings, improved designs, and even absorbable or temporary devices, are being developed. Our industry partners are very good at shepherding this process forward. If we can unlock the biological mechanisms of aneurysm formation and rupture, new medical and non-surgical treatments may evolve.”

News in brief

The latest stories from the neuro world

n FAVOURABLE OUTCOMES SEEN IN TREATMENT OF RESTENOTIC CAROTID LESIONS WITH TCAR: Writing in Stroke, Mahmoud B Malas and colleagues claim that transcarotid artery revascularisation (TCAR; Silk Road Medical) may be associated with favourable in-hospital outcomes for the treatment of restenotic carotid lesions after carotid endarterectomy (CEA). This was the key conclusion of a study that also evaluated inhospital outcomes of transfemoral carotid artery stenting (TFCAS) and redo-CEA.

For more on this story visit page 4. n ESHUNT DEVICE OPENS “NEW AVENUE” IN ENDOVASCULAR DISEASE TREATMENTS: Following the first-inman use of the eShunt system (CereVasc) to treat communicating hydrocephalus, Pedro Lylyk—who performed this pioneering procedure—talks to NeuroNews to outline the fresh possibilities the device may enable, including the treatment of non-vascular diseases using an endovascular solution.

For more on this story go to page 10. n FDA APPROVAL OF NEW SCS DEVICE MARKS “MONUMENTAL SHIFT” FOR PEOPLE WITH PAINFUL DIABETIC NEUROPATHY: The Senza system (Nevro) recently received US Food and Drug Administration (FDA) approval, allowing it to be deployed in the treatment of chronic pain associated with painful diabetic neuropathy (PDN).

Erika A Petersen discusses the potential held by this novel, high-frequency spinal cord stimulation (SCS) device.

For more on this story visit page 20.

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2021

SNV-395

Strength has a number: 64

64-wire flow diversion. Strong. Soft. Refined.

There is strength in numbers. That’s why Surpass Evolve Flow Diverter has 64 wires instead of 48—an evolution that increases the radial force for reliable opening and precise distal landing. But it’s not just strong. Visit www.64wires.com and see what makes Surpass Evolve Flow Diverter strong, soft and refined.

Surpass Evolve Flow Diverter System RX ONLY See package insert for complete indications, contraindications, warnings and instructions for use.

Intended use / indications for use The Surpass Evolve Flow Diverter System is indicated for use in the endovascular treatment of patients (18 years of age and older) with unruptured large or giant saccular wide-neck (neck width ≥ 4 mm or dome-to-neck ratio < 2) or fusiform intracranial aneurysms in the internal carotid artery from the petrous segment to the terminus arising from a parent vessel with a diameter ≥ 2.5 mm and ≤ 5.0 mm.

Contraindications The Surpass Evolve Flow Diverter is contraindicated in the following patient types: • Patients in whom the parent vessel size does not fall within the indicated range.

• Patients in whom antiplatelet and / or anticoagulation therapy (e.g., aspirin and clopidogrel) is contraindicated.

• Patients who have not received dual antiplatelet agents prior to the procedure.

• Patients with an active bacterial infection.

• Patients in whom the angiography demonstrates the anatomy is not appropriate for endovascular treatment due to conditions such as: • Severe intracranial vessel tortuosity or stenosis; and/or • Intracranial vasospasm not responsive to medical therapy.

Potential adverse events Risks that may be associated with the use of the Surpass Evolve Flow Diverter System in the intracranial arteries include: • Adverse reaction to anesthesia, contrast or antiplatelet/ anticoagulation agents • Allergic reaction • Aphasia • Cardiac arrhythmia • Cranial neuropathy • Confusion, coma, change in mental status • Death

• Device migration, fracture, misplacement • Dissection of the parent artery • Embolism (air, clots, device fragments) • Groin injury (bleeding, pain, vessel/nerve damage) • Headache • Hemiplegia • Hydrocephalus • Implant or parent vessel stenosis • Implant thrombosis/occlusion • Infection • Intracerebral bleeding • Mass effect • Myocardial infarction • Neurological deficits • Perforation or rupture of aneurysm • Perforation of Parent Artery • Progressive neurologic symptoms related to intracranial aneurysm (IA) • Pseudoaneurysm formation • Reaction to radiation exposure (i.e., alopecia, burns ranging in severity from skin reddening to ulcers, cataracts, delayed neoplasia) • Renal failure • Retroperitoneal hematoma • Seizure • Stroke • Subarachnoid hemorrhage • Thromboembolism from device • Thrombosis of parent artery or branch vessel • Transient ischemic attack (TIA) • Vasospasm Risks that are eye related with the use of the Surpass Evolve Flow Diverter System may include: • Amaurosis fugax/transient blindness • Blindness

• Diplopia • Reduced visual acuity/field • Retinal artery occlusion • Retinal ischemia • Retinal infarction • Vision impairment Warnings • Contents supplied STERILE using an ethylene oxide (EO) process. Do not use if sterile barrier is damaged. If damage is found, call your Stryker Neurovascular representative.

• For single patient use only. Do not reuse, reprocess or resterilize. Reuse, reprocessing or resterilization may compromise the structural integrity of the device and/or lead to device failure which, in turn, may result in patient injury, illness or death. Reuse, reprocessing or resterilization may also create a risk of contamination of the device and/ or cause patient infection or cross-infection, including, but not limited to, the transmission of infectious disease(s) from one patient to another. Contamination of the device may lead to injury, illness or death of the patient.

• After use, dispose of product and packaging in accordance with hospital administrative and/ or local government policy.

• This device should only be used with adequate fluoroscopic guidance by physicians who have received appropriate training in interventional neuroradiology or interventional radiology, and training on the use of this device as established by Stryker Neurovascular.

• Persons allergic to nickel, cobalt chromium or platinum tungsten metal may suffer an allergic response to this system.

• Appropriate anti-platelet and anti-coagulation therapy should be employed in accordance with standard medical practice.

• [Clinical Warning] The safety and effectiveness of the device has not been evaluated or demonstrated for ruptured intracranial aneurysms.

• [Clinical Warning] A decrease in effectiveness has been observed in subjects aged > 65 years old, subjects with history of smoking and history of prior non-target intracranial aneurysm treated.

• [Clinical Warning] Placement of multiple Surpass Evolve Flow Diverters may increase the risk of ischemic complications. Implantation of more than one Surpass Evolve Flow Diverter in non-clinical in vivo studies showed an increase in the generation of platinum microparticulates in the surrounding vessel tissues. The presence of the platinum microparticulates did not produce any adverse pathological changes such as overt inflammation or altered healing in the implanted vessels in the animals; however, the risk of platinum microparticulates in human patients is unknown.

• [Clinical Warning] Delayed aneurysm rupture may occur with large and giant intracranial aneurysms.

Cautions / precautions • Carefully weigh the benefits of treatment vs. the risks associated with treatment using the device for each individual patient based on their medical health status and risks factors for intracranial aneurysm rupture during their expected life time such as age, medical comorbidities, history of smoking, intracranial aneurysm size, location, and morphology, family history, history of prior asymptomatic subarachnoid hemorrhage (aSAH), documented growth of intracranial aneurysm on serial imaging, presence of multiple intracranial aneurysms, and presence of concurrent pathology. The benefits of device use may not outweigh the risks associated with the device in certain patients; therefore, judicious patient selection is recommended.

• This device has not been evaluated for pediatric use.

• The safety and effectiveness of the device has not been established in the treatment of small and medium wide-neck intracranial aneurysms.

• Experience with endovascular implants indicates that there is a risk of stenosis. Subsequent stenosis may require dilatation of the vessel segment containing the device.

The risks and long-term outcome following dilatation of endothelialized devices is unknown at present.

• A thrombosing aneurysm may aggravate pre-existing or cause new symptoms of mass effect and may require medical therapy.

Stryker or its affiliated entities own, use, or have applied for the following trademarks or service marks: Stryker, Surpass Evolve. All other trademarks are trademarks of their respective owners or holders.

The absence of a product, feature, or service name, or logo from this list does not constitute a waiver of Stryker’s trademark or other intellectual property rights concerning that name or logo.

Copyright © 2021 Stryker AP003335 v1.0

• Operators should take all necessary precautions to limit X-radiation dose to patients and themselves by using sufficient shielding, reducing fluoroscopy times, and modifying X-ray technical factors where possible.

• Lower intracranial aneurysm occlusion rates may be associated with giant intracranial aneurysms (>25mm).

• Lower intracranial aneurysm occlusion rates may be associated with implants that are not fully apposed to the vessel wall.

MRI safety information Non-clinical testing demonstrated that the Surpass Evolve Flow Diverter is MR Conditional for single and overlapping up to 60mm in length. A patient with the Surpass Evolve Flow Diverter can be scanned safely in an MR system under the following conditions: • Static magnetic field of 1.5 Tesla and 3 Tesla, only • Maximum spatial gradient magnetic field of 3,000 Gauss/ cm (30 T/m) • Maximum MR system reported, whole body averaged specific absorption rate (SAR) of 2 W/kg in the Normal Operating Mode Under the scan conditions defined, the Surpass Evolve Flow Diverter is expected to produce a maximum temperature rise of 3.0°C after 15 minutes of continuous scanning (i.e., per pulse sequence). In non-clinical testing, the image artifact caused by the Surpass Evolve Flow Diverter extends approximately 10mm from this implant when imaged using a gradient echo pulse sequence and a 3 Tesla MR system. The lumen cannot be visualized on gradient echo or T1- weighted, spin echo pulse sequences. Caution: The Surpass Evolve Flow Diverter may create local field inhomogeneity and susceptibility artifacts during magnetic resonance angiography (MRA), which may degrade the diagnostic quality to assess effective intracranial aneurysm treatment. The health state of the patient or the presence of other implants may require reduction of the MRI limits.

Stryker Neurovascular 47900 Bayside Parkway Fremont, CA 94538 www.stryker.com Date of release: FEB/2021 EX_EN_US

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September 2021 | Issue 43

Carotid Stenosis Treatments

TCAR may be associated with favourable outcomes for treatment of restenotic carotid lesions Transcarotid artery revascularisation (TCAR; Silk Road Medical) may be associated with favourable in-hospital outcomes for the treatment of restenotic carotid lesions after carotid endarterectomy (CEA)—following a study that also evaluated in-hospital outcomes of transfemoral carotid artery stenting (TFCAS) and redo-CEA. WRITING IN THE JOURNAL Stroke, Mahmoud B Malas (chief of Vascular and Endovascular Surgery, UCSD [University of California San Diego], San Diego, USA) et al describe a non-randomised, retrospective analysis of patients undergoing treatment for postCEA restenosis. Despite this indication being linked to a greater risk of ipsilateral stroke, an optimal procedural modality for it has yet to be determined, they note.

The study’s researchers analysed a large contemporary cohort of patients in the vascular quality initiative (VQI) database—a prospectively maintained database containing patient- and procedure-specific data from more than 700 centres across the USA and Canada—who underwent TCAR, redoCEA, or TFCAS, after ipsilateral CEA between September 2016 and April 2020.

Patients with prior ipsilateral carotid artery stenting (CAS) were excluded from this analysis, however.

The primary outcome in this study was the composite endpoint of inhospital stroke or death, with secondary endpoints being in-hospital stroke, death, myocardial infarction (MI), the composite endpoint of stroke or transient ischaemic attack (TIA), and the composite endpoint of stroke, death, or MI. For the purposes of the study, strokes included any ipsilateral or contralateral cortical or vertebrobasilar

stroke, TIAs included any ipsilateral or contralateral TIA, and MI was diagnosed based on elevated troponin levels or electrocardiogram (ECG) changes.

The final patient cohort included a total of 4,425 patients—1,676 TCAR (37.9%), 1,786 TFCAS (40.4%), and 963 redo-CEA (21.8%) patients. TCAR, despite a “considerably higher burden of comorbidities”, was associated with lower odds of in-hospital stroke/death (odds ratio [OR], 0.41 [95% confidence interval [CI], 0.24–0.70], p=0.021), stroke (OR, 0.46 [95% CI, 0.23–0.93], p=0.03), MI (OR, 0.32 [95% CI, 0.14–0.73], p=0.007), stroke/TIA (OR, 0.42 [95% CI, 0.24–0.74], p=0.002), and stroke/death/MI (OR, 0.41 [95% CI, 0.24–0.70], p=0.001) when compared with redo-CEA. There was no significant difference in the odds of death between the two groups (OR, 0.99 [95% CI, 0.28–3.5], p=0.995), Malas et al also report. TCAR was associated with lower odds of stroke/TIA (OR, 0.37 [95% CI, 0.18–0.74], p=0.005) when compared with TFCAS too—although there was no significant difference in the odds of stroke, death, MI, stroke/death, or stroke/ death/MI, between TCAR and TFCAS. “To our knowledge, this is the first and largest study of its kind to demonstrate better perioperative outcomes with TCAR when compared with both TFCAS and redo-CEA in the treatment of recurrent

Higher risk of periprocedural hazards for patients undergoing carotid interventions after thrombolysis A systematic review and meta-analysis has demonstrated that patients undergoing carotid interventions after thrombolysis have a higher risk of periprocedural hazards, compared with those patients who did not have prior thrombolysis. Authors Stavros K Kakkos (University Hospital of Patras, Patras, Greece) and colleagues report their findings in an article published online in the European Journal of Vascular and Endovascular Surgery (EJVES).

“PATIENTS UNDERGOING CAROTID endarterectomy (CEA) or carotid artery stenting

carotid disease after endarterectomy,” classes (IV–V), and receive general Malas and colleagues write. “The anaesthesia. Malas et al add that, significant differences in primary and notably, TCAR was associated with a secondary endpoints between TCAR 60% reduction in the odds of stroke/TIA and redo-CEA were evident despite when compared with TFCAS and—after adjustment for patient characteristics, and stratifying by symptomatic status—was several potential confounders.” associated with a 70% reduction in In addition, they note that—although the odds of in-hospital stroke, a 90% they are unable to establish causal reduction in the odds of in-hospital determinants for the unfavourable stroke/TIA, and 50% and 60% reductions outcomes associated with redoin the odds of stroke/death and stroke/ CEA—they believe this may be due death/MI in the asymptomatic group, to longer surgery times with increased although no significant difference was manipulation of the carotid bifurcation, observed among symptomatic patients. and prolonged general These favourable outcomes anaesthetic exposure, but it may be due to the technical could also relate to lesion or advantages of TCAR, anatomic characteristics that they claim, referencing its increased case complexity and utilisation of dynamic flow therefore precluded minimally reversal, which reduces invasive intervention. When cerebral microembolisation. compared with TFCAS, they “Whereas in-hospital add, redo-CEA was associated outcomes from a prospective with higher mortality but Mahmoud B Malas registry are not sufficient similar rates of stroke and MI. to demonstrate the overall, Thus, they recommend avoidance of long-term benefit of any specific redo-CEA in high-risk patients, and assert revascularisation technique, they provide that “the findings in our study align with a real-world evaluation of periprocedural the prior literature and raise questions risks and how they differ based on patient regarding the role of redo-CEA in the demographics and comorbidities,” the treatment of recurrent carotid disease authors write, before concluding that— after endarterectomy”. while their findings support the idea that They also report that their study TCAR may be associated with favourable found patients undergoing TCAR, when outcomes in treating restenotic carotid compared with TFCAS, were more likely lesions—additional long-term studies are to be older (aged over 75 years), have warranted “before we can establish the coronary artery disease, be in higher best procedural therapy for the treatment American Society of Anesthesiologists of restenosis after CEA”.

To our knowledge, this is the first and largest study of its kind to demonstrate better perioperative outcomes with TCAR when compared with both TFCAS and redo-CEA in the treatment of recurrent carotid disease after endarterectomy.” Malas et al

(CAS) after thrombolytic therapy have a higher risk of these studies, 2,557 of whom underwent either CEA periprocedural stroke and death, compared with patients (n=2,076) or CAS (n=481) following thrombolysis. undergoing CEA or CAS without prior thrombolytic After CEA, the authors report that the pooled therapy,” the authors write. However, they note that the periprocedural stroke/death rate was 5.2% and difference was statistically significant only for CAS. In intracranial haemorrhage was 2.4%. After CAS, the regards to other hazards, Kakkos et al note that there pooled perioperative procedural stroke/death rate was was also a higher risk of periprocedural intracranial 14.9% and ICH was 5.5%. haemorrhage (ICH) and local haematoma in patients In case control studies comparing CAS outcomes undergoing carotid interventions after thrombolysis. in patients receiving thrombolytic therapy versus no One of the findings that Kakkos and colleagues state thrombolytic therapy, the authors communicate that is “of most practical importance” is that periprocedural periprocedural stroke/death was significantly higher risks of stroke and death appeared to be higher if CEA after thrombolytic therapy (5.2% vs. 1.5%; odds ratio was performed in the first few days after thrombolysis.

[OR] 8.49; 95% CI, 2.12–33.95), as was ICH (5.4% vs.

This inverse relationship between timing to CEA and 0.7%; OR, 7.48; 95% CI, 4.69–11.92). periprocedural stroke/death “mandates careful patient Kakkos and colleagues also detail that metaselection and suggests that it may be safer to defer CEA regression analysis demonstrated an inverse for six to seven days after thrombolytic association between the time interval from intravenous therapy,” they posit in EJVES. thrombolytic therapy to undergoing CEA and the risk of Using the Medline, Scopus, and periprocedural stroke/death (p=0.032). “Perioperative Cochrane databases, Kakkos et stroke/death was 13% when CEA was performed al identified 25 studies involving three days after thrombolytic therapy and 10.6% when patients who underwent either CEA performed four days after thrombolytic therapy, with or CAS after thrombolytic therapy to the risk reducing to within the currently accepted 6% include in their systematic review threshold after six–seven days had elapsed,” they and meta-analysis. There were write in EJVES, communicating the results of Stavros K a total of 147,810 patients in their analysis.

Kakkos

Issue 43 | September 2021

Advertorial

5

THIS ADVERTORIAL IS SPONSORED BY PERFLOW

Cascade device provides the best of both worlds in treating cerebral aneurysms The Cascade Net (Perflow)—a non-occlusive remodelling net used in the treatment of cerebral aneurysms—is the first and only device capable of providing continuous blood flow during these repair procedures, and is designed to allow physicians to pack embolisation coils while also preventing risks of protrusion or entanglement into the mesh of the device. Paul Bhogal (Royal London Hospital, London, UK) discusses his experiences with this innovative technology, and how it compares to what was previously available in this space.

B

hogal, who has used the “classic” both elective and ruptured aneurysms Cascade, the Cascade Agile, and overall.” to a lesser extent the Cascade17— which was launched in Europe earlier this Best of both worlds year—considers these devices to be suitable Regarding further patient-related benefits, for a wide range of aneurysm locations and Bhogal highlights the fact that the device’s complexities. These consist of those found mesh—which is based around Perflow’s in what he refers to as classic locations, proprietary CEREBRAL NET braiding Paul Bhogal including the internal carotid artery (ICA), technology—is tight, yet compliant and soft, as well as in middle cerebral artery (MCA) making things “relatively atraumatic” for bifurcations and even more distal aneurysms, such as the patient undergoing a procedure with the Cascade. those in the anterior communicating artery (Acom), However, he believes an even more significant as the Cascade can safely handle tortuous anatomies. positive feature seen in the Cascade is the fact it is “For all of those locations, in the vast majority of non-occlusive. One of the potential issues that is cases, the use of the Cascade device is a good option,” associated with remodelling balloons—a commonly he adds. “The classic situation where Cascade could used alternative approach to aneurysm repair—is the be considered is wide-necked aneurysms—I have fact that they occlude the vessel they are deployed in, successfully used it for both ruptured and unruptured cutting off blood flow, and can therefore only be kept aneurysms, so in my experience it is suitable there as inflated for a limited period of time. “But, if you can well.” create a device that will still allow blood flow through There is no shortage of benefits associated with the the blood vessels, and then also completely block the device from the physician’s perspective, according neck of the aneurysm so that you can just coil happily, to Bhogal, with visual markers on the device making then you have got the best of both worlds,” he says. it very easy to see during procedures, and enabling That is where, Bhogal claims, the Cascade device it to be positioned correctly, with confidence, at the comes in. aneurysm neck. The Cascade’s handle—in addition Problems relating to occluded blood vessels can be to the two settings it offers, auto-lock mode and seen in a balloon-based procedure as short as five or continuous mode—contributes to it being “very ten minutes in duration—with Bhogal alluding to one straightforward and intuitive to use”, in Bhogal’s case performed by a colleague of his that resulted in view, while inflating and deflating the net is extremely the patient having an anterior cerebral artery (ACA)simple as well. “The learning curve is relatively short, territory stroke despite the blood vessel only being as it is not a complicated device to use,” he says. “The occluded for a matter of minutes. As Bhogal notes, main thing is just learning where to position the device “something like the Cascade would have been much relative to the neck of the aneurysm—but that can better” in this instance, before referencing a separate, be learned within one case, or even during training.” anecdotal example from another colleague who had the Bhogal adds that the option of partially resheathing Cascade net open for 45 minutes during a procedure the Cascade device while using it allows for focused and did not see any thromboembolic complications in deployment and controllable radial force, before the patient. “For me, this device represents something noting that the interaction between the microcatheter and manipulation of the compliant net structure also supports its use in Y-bifurcations.

“I think there are a variety of ways in which the device could potentially mean that you see economic benefits in the long term—dense coil packing means recurrence is less likely, and therefore so is repeat treatment, for example,” Bhogal notes. “That is also nicer for the patient, as they do not have to come in and have the stress of dealing with a second or third operation.” Regarding characteristics that could be seen to benefit physicians and patients alike, Bhogal also touches on complications—or lack thereof— associated with the device. “Personally, I have not seen any complications when using the device, certainly no disastrous or major thromboembolic complications, or vessel ruptures. In fact, I think it would be extremely difficult to cause a vessel rupture because of the nature of the device. And, no complications—or, at least, a Cascade Net in low rate of complications—means shorter hospital Y-bifurcation stays for elective cases, and improved outcomes for

Cascade Net in fully unsheathed (top) and partially unsheathed positions

that is effectively as close to a balloon as possible, but is non-occlusive, meaning it has most of the advantages of a balloon without the major disadvantage,” he states, adding that the Cascade can therefore be seen as something akin to a “controllable and fully retrievable flow diverter”.

Freedom from complications

To assess whether there was any potential risk of coil loops intertwining with the Cascade device’s mesh mid-procedure, or protruding out of the target aneurysm and entering other blood vessels, Bhogal led a series of in vitro tests investigating how the device performed in silicone aneurysm models. A total of 480 attempted coilings were performed in these tests, and the results were published in the journal Interventional Neuroradiology (INR) last year. Bhogal and his colleagues concluded that no episodes of coil protrusion through the Cascade mesh were observed, and he further states that, due to the device’s mesh being so tightly woven, “the likelihood of coils interlooping with the device without you realising is almost zero”. In these tests, he and his colleagues also saw no coil protrusion into the parent vessel when the Cascade was deployed across the aneurysmal neck— concluding that the device therefore offers “robust protection” against coil herniation.

In addition to this evidence that the odds of any procedural complications occurring while using the Cascade are very low, Bhogal notes the other major finding from these tests—a flow-diverting effect, demonstrated by a flow-velocity reduction (FVR) of 23% and reduced intra-aneurysmal flow following inflation of the Cascade, compared to without the device in situ. “This means that, once the device is inflated, you are causing some stagnation in the aneurysm during the procedure while you are coiling,” he adds. “This also made me think that it is probably going to be safer in case of a ruptured aneurysm too, because you do at least have some flow diversion away from the aneurysm.” In summary, Bhogal states that—with the Cascade—the main innovation Perflow has brought to the market is “very good braiding technology”, before asserting that the company’s ability to create fairly small, controllable devices is “impressive”.

Paul Bhogal is a consultant interventional neuroradiologist at the Royal London Hospital—part of Barts Health NHS Trust—in London, UK, and the interventional neuroradiology research lead and co-founder of the Barts Research and Advanced Interventional Neuroradiology (BRAIN) conference.

He has an interest in new devices and technologies, and has used the Cascade device in approximately 20 cases to date.

DISCLAIMER: The Cascade Net has received CE certification for use in Europe, but is currently not available for sale in the USA.

6

September 2021 | Issue 43

Advertorial

THIS ADVERTORIAL IS SPONSORED BY NICOLAB

AI holds the key to timely interventions in a field where every second counts In 2021, the Royal Infirmary of Edinburgh and networking hospitals are implementing StrokeViewer (Nicolab)—which is an artificial intelligence (AI) solution that helps physicians with the triage and diagnosis of stroke patients. Jonathan Downer (University of Edinburgh, Edinburgh, UK) shares how new technologies like StrokeViewer are set to transform care across his network.

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hen it comes to stroke, every second counts.

Efficient triage and quick decision-making are vital to save as much viable brain tissue as possible. Based on current figures and National Health Service (NHS) projections, the stroke care system in Scotland in the UK is suboptimal.1 At least in part due to an insufficient workforce of trained radiologists available 24/7 in referring hospitals, stroke patients may experience up to four-hour delays before their scans are read and appropriate treatments start.

In the first half of 2020 in Edinburgh, no mechanical thrombectomies were performed. This was due to a lack of resource provision. However, the NHS longterm plan advocates for an expansion of mechanical thrombectomy from 1% of stroke patients currently receiving the treatment in the UK to 10%, which will allow 1,600 more people to be independent after their stroke each year.2 Although funding allocated in the second half of 2021 has kickstarted the expansion of thrombectomy services in Edinburgh, there is still a long way to go to reach these targets. Bringing new and reliable AI technology into the clinical workflow helps speed up diagnosis, streamline communication, and securely centralise all patient data, which can then be accessed any time and any place. Implementing StrokeViewer across our NHS stroke network later this year is a vital step needed to optimise our stroke workflow to provide patients with adequate and timely care.

AI in the real world

As a neurointerventionist on call, it is my priority to know accurately and quickly if a patient will benefit from mechanical thrombectomy. StrokeViewer notifications will allow me to be on the front foot from the start, as I will be aware of thrombectomy candidates from across our network as soon as a scan is acquired rather than waiting for referral. This has the potential to reduce significant time delays, and to enhance teamwork and collaboration across the emergency stroke care network.

With StrokeViewer, I have access to AI-analysed stroke scans within minutes. I can also use the certified

Implementing StrokeViewer across our NHS stroke network later this year is a vital step needed to optimise our stroke workflow to provide patients with adequate and timely care.”

diagnostic viewer if I need a closer look. This system allows me to make quick and accurate treatment decisions—all from my mobile. This saves a lot of time but also makes the process more efficient by bringing the entire team onto the same platform.

Jonathan Downer And, most importantly, the patient can get the right treatment with minimal delay, which gives them a better prognosis.

In addition to diagnosis and triaging of patients, StrokeViewer also has a 3D treatment planning view. This works by segmenting brain arteries and tissues in the certified viewer so that interventional neuroradiologists can plan for thrombectomy ahead of time. You can rotate the neurovascular structures and cut away tissue in the viewer to visualise the aortic arch and identify the most suitable kit for the procedure.

I believe technology deserves a place in the future of healthcare, in particular for emergencies like thrombectomy where time is so critical. It can instil confidence in team members with less experience, overcome limited staff numbers and ultimately improve the standard of care, giving someone a better chance of returning to a normal life.

References: 1. https://www.strokeaudit.scot.nhs.uk/Publications/docs/2020-09-01-SSIPReport.pdf 2. https://www.longtermplan.nhs.uk/online-version/chapter-3-furtherprogress-on-care-quality-and-outcomes/better-care-for-major-healthconditions/stroke-care/#ref

Jonathan Downer is a consultant neurointerventionist and honorary clinical senior lecturer at the University of Edinburgh, Edinburgh, UK. His interests are in imaging and minimally invasive neurological therapy for neurovascular disease, stroke, subarachnoid haemorrhage, intracranial aneurysms, arteriovenous malformations, and dural arteriovenous fistulas of the brain and spine.

What is StrokeViewer?

StrokeViewer is a cloud-based, end-to-end clinical support solution that combines a broad portfolio of AI algorithms and a unique platform supporting fast image exchange between hospitals and stroke physicians, driving informed decision-making when time is most critical. Once implemented into a hospital system, all stroke patient computed tomography (CT) scans are automatically pushed to a secure cloud environment where the scans are analysed by powerful AI algorithms.

Every stroke patient deserves adequate access to care, regardless of their background and geographic location. When it comes to stroke, fast diagnosis and the right treatment decision are vital for the best patient outcome—no matter what time of day.

Currently, in Scotland, we often do not have the human resources to provide timely access to care.

There has been a lot of difficulty recruiting and retaining radiologists, and an even shorter supply of specialist neuroradiologists.

With the implementation of StrokeViewer, experts can be notified of patient results within minutes following acquisition of CT scans.

Physicians can then review high-quality, AIenhanced scans and use a mobile DICOM viewer that is fully certified for clinical diagnosis. This platform is available any time of day on our mobile device, allowing us to diagnose patients remotely, including from out-of-hospital locations.

StrokeViewer (Availability of algorithms is dependent on your region)

Issue 43 | September 2021

Stroke Interventions

SNIS 2021

Remote stroke interventions raise several unique ethical challenges At the Society of NeuroInterventional Surgery’s 18th annual meeting (SNIS; 26–29 July 2021, Colorado Springs, USA and virtual), Jeffrey Saver, professor of Neurology at the University of California, Los Angeles (UCLA) Medical Center and director of the UCLA Stroke Center (Los Angeles, USA), discussed the various ethical considerations that need to be taken into account regarding robotic applications in neuroendovascular interventions, and remote stroke care, stating that “we all need to work together to make sure patients have the best outcome”.

DURING A SESSION THAT also saw multiple presentations demonstrating the potential benefits and new possibilities enabled by these novel technologies, Saver claimed this is an area that brings up “several unique domains of challenging bioethics”— including the ethics of remote care, the ethics of introducing new surgical techniques and training protocols, the ethics of robot-assisted procedures, and even autonomous, artificial intelligence (AI)-powered robotic systems, which are currently physician-supervised but may be unsupervised in the future.

The first specific ethical consideration Saver outlined was “compromised informed consent” on the patient’s part.

He emphasised the criticality of full disclosure of the fact many of these procedures are fairly new, and, as such, there is limited evidence on both their benefits and their risks. “There is a

general tendency for patients to equate newness with increased benefit—and we have to counter this tendency when we talk with them,” he added.

Saver also noted that, while trust in the authority of the interventionist performing the given procedure should be encouraged, “humility”—to reflect their often-limited experience in performing these procedures compared to more traditional surgeries—is important here too.

Saver went on to state that various conflicts of interest on the physician’s side are significant too, and should be fully disclosed to the patient, with these ranging from direct financial benefits and other incentives, and brand loyalty, to the “elevated social status” of being a surgical innovator and bias towards performing a technique in which training has been invested—referring to the phenomenon of “sunk cost” here as well.

Potential racial disparities in stroke care highlighted at SNIS 2021 The possibility of racial disparities in the way US stroke patients are treated was highlighted at the Society of NeuroInterventional Surgery’s 18th annual meeting (SNIS; 26–29 July 2021, Colorado Springs, USA and virtual)—as was the importance of ensuring that all patients receive the same level of care after having a stroke.

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ne study presented at the conference, entitled “Racial disparity in mechanical thrombectomy utilization: Multicenter registry results from 2016–2020”, analysed the records of 34,596 patients from 42 hospitals across 12 US states, over a five-year period, and found that Black stroke patients were 28% less likely than white patients to undergo a minimally invasive thrombectomy procedure to remove blood clots from arteries in the brain.

And, despite the fact that strokes caused by blockages of a large artery in the brain must be diagnosed as soon as possible—as the effectiveness of

He noted that harm to the patient, including increased morbidity and mortality, is the “most important” ethical consideration that may be associated with robotic or remote procedures. “We need stringent QI [quality improvement] and reviews of every case,” Saver added. He went on to state that research burdens should not be placed disproportionately on disadvantaged or poorer communities, despite the fact that patients from these backgrounds may only gain access to advanced care by participating in

Jeffrey Saver

innovative therapy systems—something he described as a “challenging ethical issue”—and added that these expensive technologies should not take too many resources away from proven care approaches either.

Another factor that Saver claimed is especially pertinent to remote intervention is the notion of a “diminished physicianpatient relationship”, whereby the patient has reduced access to the interventionist. “We need to be sure that the interventionist maximises their

a thrombectomy in reducing disability decreases with time—the researchers also found that Black patients were 27% less likely than white patients to arrive at the hospital within five hours of stroke onset, and 30% less likely to be diagnosed with a blockage of a large artery in the brain upon arrival.

“Black patients in the USA consistently experience worse health outcomes than white patients, leading to staggering racial health gaps,” said Adam Wallace, a neurointerventional surgeon at Ascension Columbia St Mary’s Hospital in Milwaukee, USA, and the study’s lead author. “It is imperative that we take steps to ensure that all stroke patients are treated with the utmost urgency and receive optimal care, including surgery when appropriate, so they can experience the highest quality of life after stroke.”

The authors note that further research is needed to assess whether the disparities observed in their study’s results can be reduced by community stroke education, technologies that allow thrombectomy to be performed later after stroke onset, and more aggressive patient screening for brain artery blockages.

In addition to these findings, a separate study presented at SNIS 2021 found that race, in combination with other factors, predicted how quickly individuals with stroke got to care centres to receive vital neuroendovascular surgery, including thrombectomy.

The study, entitled “Disparities in stroke: Influence of socioeconomic status and race on timely access to mechanical thrombectomy”, reviewed data from 305 patients collected between 2016 and 2020 to find out how factors including race, socioeconomic status, health insurance coverage and driving distance to a stroke centre influenced how quickly individuals were

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availability to the patient—not just during the case, but by telemedicine pre and post if they are doing a case remotely,” he stated. Saver noted that there could be a risk for decreased empathy on the part of the physician for patients and families with whom they have never had direct contact too.

On a similar note, he alluded to the “diffusion of responsibility” that may be seen to be associated with these novel surgeries, referring to a “broader network of interdependent care” than is common in medicine. This network involves the remote interventionist, local physicians and nurses, hardware manufacturers, software coders, the AI system being deployed, and more. “We need to make sure we have an active, continuous partnership,” Saver also said.

As well as giving a nod to the more distant future in this ever-evolving space within neurosurgery—that being the ethics of fully autonomous, robotic interventionists—Saver chose to end his presentation on a more positive note.

Firstly, he encouraged the attending audience to consider the future of their own patients, but also future generations of patients who, further down the line, stand to benefit from many of the innovations currently being advanced, adding that “a procedural speciality does require a little bit of risk taking”. Saver concluded his talk by addressing the need to consider the wellbeing of the physicians themselves in this debate— noting that the minimised radiation exposure and reduced lead-wearing risks that neurointerventionists may gain via robotic or remote surgical techniques are “a very important ethical goal” as well.

able to receive stroke surgery.

The authors measured the time between each patient’s stroke onset and the beginning of surgery, with a focus on the time from onset to arrival at the hospital. The researchers found that race was among the predictors for how quickly patients made it to a stroke centre—also impacting how quickly they can have surgery. Other factors included driving distance, the patient’s stroke severity level and whether a patient discovered the stroke symptoms upon waking. The authors also found that income, age and gender were not predictors for timely access to care among this group of patients.

“Your race, ZIP code or socioeconomic status should not determine whether you make it home from the hospital after a stroke,” said Ricardo Hanel, lead author for the study, and an endovascular neurosurgeon and co-medical director of the Baptist Stroke & Cerebrovascular Center in Jacksonville, USA. “This study shows that equity of access to care is critically important in achieving excellent outcomes for all.”

Your race, ZIP code or socioeconomic status should not determine whether you make it home from the hospital after a stroke.”

Ricardo Hanel

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September 2021 | Issue 43

Mechanical Thrombectomy

Repeated clot retrieval attempts linked to poorer functional outcome in acute ischaemic stroke patients Repeated clot retrieval attempts are associated with an increased rate of emboli to new territory (ENT) and greater infarct growth—resulting in poorer functional outcomes in acute ischaemic stroke patients even after successful recanalisation has been achieved. These findings are based on data from two pooled, multicentric prospective patient registries and are published in Neurology.

“AMONG SUCCESSFULLY RECANALISED patients, clot retrieval at the first clot retrieval attempt significantly reduced infarct growth and improved functional outcome,” Wagih Ben Hassen (Department of Neuroradiology, University of Paris, Paris, France) and colleagues write in their report. “Each additional retrieval attempt was correlated with a higher rate of ENT and a greater increase in infarct growth volume, reducing the odds of favourable functional outcome.

These findings highlight the need for a randomised trial to define the appropriate therapeutic strategy when a first clot retrieval attempt is unsuccessful.”

In an attempt to “elucidate the link between the number of clot retrieval attempts and the functional outcome in a successfully recanalised population”,

Ben Hassen et al extracted data from two prospective registries, including consecutive acute ischaemic strokelarge vessel occlusion (AIS-LVO) patients treated with mechanical thrombectomy between January 2016 and 2019 at two large, comprehensive stroke centres in France. Anterior circulation AIS-LVO patients with a known onset of symptoms treated with endovascular therapy (EVT), and with pretreatment and 24-hour posttreatment diffusion-weighted imaging (DWI) achieving successful recanalisation—defined as expanded Thrombolysis in Cerebral Infarction Scale (eTICI) scores of 2b, 2c, or 3—were included.

Among 902 anterior circulation stroke patients with known symptom onset treated via mechanical thrombectomy, 502 patients (56.1% women; mean age=68±15 years) were eligible. A total of 419 patients achieving successful recanalisation were included—with recanalisation being obtained after one clot retrieval attempt in 224 patients (53.5%), two attempts in 107 patients (25.5%), three attempts in 49 patients (11.7%), and four or more attempts in 39 patients (9.3%). In the subsequent analysis, associations between the number of clot retrieval attempts, and ENT, infarct growth and three-month outcomes, were assessed.

Occurrence of ENT was “highly correlated” with an increasing number of clot retrieval attempts, the authors report, stating that there were 23 cases of ENT in the whole study population (5.5%), with two cases in the one clot retrieval attempt group (1%), three in the two clot retrieval attempts group (2.8%), seven in the three clot retrieval attempts group (14.3%), and 11 in the four-or-more clot retrieval attempts group (28.2%).

The one clot retrieval attempt group also had the lowest infarct growth volume and the lowest rates of ENT. Infarct growth increased linearly with the number of clot retrieval attempts in the study, Ben Hassen et al add.

In terms of functional outcomes, symptomatic intracranial haemorrhage (sICH) rates increased with the number of clot retrieval attempts. The group of one

Increased experience associated with shorter procedure times and better reperfusion rates in mechanical thrombectomy Increasing levels of experience in performing mechanical thrombectomies have been associated with shorter procedural duration and better reperfusion rates in a multicentre study—with the study’s researchers noting that a “theoretical ceiling effect” was observed after about 100 procedures.

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riting in the journal Stroke, lead author François Zhu (Department of Diagnostic and Therapeutic Neuroradiology, Nancy Regional University Hospital Center, University of Lorraine, Nancy, France) and colleagues—under the supervision of Grégoire Boulouis (Diagnostic and Interventional Neuroradiology Department of Tours Hospital, Tours, France)—detail the intention behind their study, which was to evaluate, among trained interventional neuroradiologists, the impact individual experience has on procedural performance metrics in thrombectomies.

In an introductory statement, the authors note that recent international guidelines issued by the American Heart Association (AHA)/American Stroke Association (ASA), and the European Stroke Organisation (ESO)/ European Society of Minimally Invasive Neurological Therapy (ESMINT), have

recommended a minimum level of personal experience in neurointerventions at high-volume stroke centres before performing endovascular therapy (EVT) in autonomy—but that this minimum level is “unclearly defined”, and that it is currently unknown whether technical efficiency increases after training, along with increasing EVT experience.

As such, they pooled individual EVT procedural data from five centres in the Endovascular Treatment in Ischaemic Stroke (ETIS) registry, and two additional high-volume stroke centres, and conducted a retrospective analysis including all patients treated with mechanical thrombectomy for which operator and procedural metrics were recorded. Operator experience was defined for each operator as a continuous variable, cumulating the number of thrombectomy procedures performed since January 2015, and the study’s endpoints included duration of procedure,

François Zhu

retrieval attempt experienced the lowest rate of sICH (5.8%) compared to 8.4%, 6.1% and 10% in the two, three, and four-or-more clot retrieval attempt groups, respectively. In addition, favourable functional outcome decreased with each additional clot retrieval attempt in the successfully recanalised population, and the one clot retrieval attempt group had the highest rate of favourable outcome of any group. Infarct growth was also found to be an independent negative predictor of favourable outcome in binary logistic regression analysis.

Recent studies have linked the detrimental effect of repeated clot retrieval attempts on functional outcome to the “drastic decrease” in successful recanalisation rates after each additional attempt, Ben Hassen et al note.

However, in their study, patients with a similar baseline infarct volume who achieved successful recanalisation were included to better identify an independent effect of repeated thrombectomy attempts—and they ultimately

These findings highlight the need for a randomised trial to define the appropriate therapeutic strategy when a first clot retrieval attempt is unsuccessful.”

Wagih Ben Hassen et al

found that repeated thrombectomy manoeuvres led to an increased rate of ENT, correlated to “substantial” infarct growth. The authors conclude, therefore, that “achieving successful recanalisation with the fewest clot retrieval attempts, ideally with a single pass” is key, but also stress that “successful recanalisation—even after multiple attempts—is still better than no recanalisation”.

Grégoire Boulouis

final angiographic recanalisation, the overall rate of first-pass complete recanalisation, and the rate of severe procedural complication.

Among 4,516 patients treated with EVT between January 2015 and January 2020, a total of 4,012 procedures were included in the analysis. The mean age of these patients was 70 years, and a total of 2,225 (55.5%) received intravenous tissue-type plasminogen activator (IVtPA) prior to EVT. Factors associated with shorter EVT duration in univariable analyses, the authors report, were increased operator experience, intravenous thrombolysis before EVT, local (versus general) anaesthesia, and middle cerebral artery (MCA) occlusion location. Similar results were found when considering experience as an ordinal variable, with EVT duration decreasing as the operator experience category increased, while multivariable analysis showed that higher operator experience as a continuous variable was associated with a “significantly shorter” procedural duration.

“To assess for a potential ceiling effect in the influence of operator experience

on mechanical thrombectomy duration, we sequentially excluded previous procedures by steps of 20 units,” Zhu et al add. “Using this method, we observed that prior experience lost its significant association with mechanical thrombectomy duration between 100 procedures and 120 procedures.”

In the study, increasing operator experience was “significantly associated” with recanalisation success rates as a dichotomous variable, both in univariable and multivariable models.

The researchers also assessed for a ceiling effect in the association between experience and successful recanalisation, and found the loss of significance here happened between 80 and 100 procedures. They add that there was no effect of operator experience on the overall first-pass complete recanalisation rate after adjusting for general anaesthesia, occlusion location, age and tPA use. Regarding complications, there was no association between operator experience and perforation in either direction—nor was there an association between operator experience and the rate of reported arterial dissections.

“Our study […] highlights that, even in trained neurointerventionists operating in autonomy, increasing experience in EVT is associated with better procedural metrics,” Zhu et al write. “The optimal balance between procedural efficiency and safety, and the growing need for thrombectomy-trained interventionists, is still to be found.”

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September 2021 | Issue 43

10 Novel Devices

EShunt system offers promise for endovascular treatment of hydrocephalus “I have tried several devices in the last 10 or 20 years, but I think this is absolutely different—this is the first time that we have treated non-vascular problems [using an] endovascular solution,” Pedro Lylyk (Clinica Sagrada Familia, Buenos Aires, Argentina) told attendees at the Society of NeuroInterventional Surgery’s 18th annual meeting (SNIS; 26–29 July 2021, Colorado Springs, USA and virtual), documenting first-in-human experience with the eShunt system (CereVasc)—an investigational device for the treatment of communicating hydrocephalus (CH).

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ylyk is the principal investigator in the ETCHES I (Endovascular treatment of communicating hydrocephalus with the eShunt system) trial assessing the use of the device, which is implanted through a leg vein using X-ray guidance. EShunt is described as the first minimally invasive treatment for CH—the abnormal build-up of fluid in the brain.

The current standard of care for CH is the ventriculoperitoneal (VP) shunt, Lylyk told SNIS attendees during the late-breaking abstract session in which he presented the results of the first-in-human case. VP shunts have been shown to have high complication and failure rates, Lylyk added, with reports describing that >40% of VP shunts fail within the first two years of implantation.

Therefore, Lylyk and colleagues believed that, using modern fluoroscopic imaging and 3D vascular visualisation, a less-invasive option may be viable.

EShunt is designed to eliminate the need for a craniotomy or surgical opening into the skull, passage of a catheter through white matter of the brain, or subcutaneous tunnelling across the chest and abdomen for placement of a long outflow catheter into a second surgical incision in the abdomen.

The shunt consists of a subarachnoid space (SAS) anchor, a shunt body of 35mm in length, and a slit

proximal valve, Lylyk described in his presentation, noting that the delivery system is comprised of two components: one distal, that stays at the cavernous sinus; and one proximal, which is a 4 French penetrating catheter with a 20G needle, protected by a retractable needle guard.

Describing the case, Lylyk told SNIS attendees that the patient, an 84-yearold female, was referred five days after subarachnoid haemorrhage (SAH) and developed neurological deterioration after a further five days. CH was detected on computed tomography (CT), prompting the implantation of the eShunt. The patient died 59 days after occurrence of the SAH after developing sepsis secondary to a respiratory infection progressing to renal failure, but Lylyk described early experience with the device as encouraging.

“We achieved the early communication between the CSF [cerebrospinal fluid] and the blood,” Lylyk told NeuroNews in an interview following his SNIS presentation, in which he discussed the procedure. “We dropped the pressure inside the brain [which returned] within the next 36 hours up to normal, so that was a big

Brain-computer interface technology opens up “whole new world” of therapies “We are starting to help patients in ways that we did not think were possible,” Thomas Oxley (Mount Sinai Hospital, New York, USA) tells NeuroNews, referring to the potential of brain-computer interface (BCI) technology. Alongside his role as a vascular and interventional neurologist, Oxley is chief executive officer of Synchron, developer of the Stentrode motor neuroprosthesis. The Stentrode is an implantable BCI device that, according to Oxley, is the first of its kind to be in the early feasibility clinical stage in the USA following US Food and Drug Administration (FDA) approval of Synchron’s investigational device exemption (IDE) application last month. Speaking to NeuroNews following a presentation on the topic at the Society of NeuroInterventional Surgery’s 18th annual meeting (SNIS; 26–29 July 2021, Colorado Springs, USA and virtual), Oxley gives an overview of the COMMAND early feasibility study, anticipates key results, and considers more generally how BCI technology could shape the future of deep brain stimulation.

“THE GOAL OF WHAT WE ARE doing is to get to a pivotal trial,” Oxley states, detailing that the Stentrode is a Class III device and so needs premarket approval (PMA) from the FDA. In order to begin a pivotal study, it is first necessary to go through a feasibility study. “I believe we are the only company with an implantable BCI in the early feasibility clinical stage in the USA,” he informs NeuroNews. “We are collecting data on safety and efficacy that will enable us to shape the pivotal trial to come in the next couple of years in order

to head towards approval and then get the technology out to the market.”

“The biggest challenge”: Quantifying a new metric

The aim of the feasibility study is twofold, Oxley communicates. “On the safety side, we are first and foremost demonstrating that it is safe to leave a stent electrode inside a venous system and inside the brain,” with thrombosis and stroke being the two key events that would indicate safety issues. “We have had neither of those events so far,” he

achievement. The patient had improved ICP [increased intracranial pressure] of the brain, so that was the first achievement.”

However, Lylyk also commented that the proof of the concept also potentially opens the door for its wider usage. “This is a fantastic new solution for [treating] non-vascular problems by endovascular means,” Lylyk said. “This is the first case in which we achieved the percutaneous endovascular transluminal access to the central nervous system and that may have nice implications for an access platform.

“We can deliver gene therapy, brain stem cells, or do endovascular surgery that way. Also, we achieved the first transdural venous to cisternal punctures safely, without any haemorrhage inside the brain,” he noted. “I think we have proved the concept that we can join the CP [cerebellopontine] angle, the cistern of the CP angle, with the IPS [inferior petrosal sinus] with rapid and sustained decreases of ICP.” Pedro Lylyk added that he is “very excited” Lylyk about the potential of the device. “I think this is a new avenue for us for the endovascular treatment of many other diseases.

It is just the first step, but I think it is a big step,” he told NeuroNews.

I think this is a new avenue for us for the endovascular treatment of many other diseases. It is just the first step, but I think it is a big step.”

Pedro Lylyk

tells NeuroNews.

“On the efficacy side, the question is how to quantify the utility of a BCI, or a motor neuroprosthesis,” Oxley relays. “That metric has not been demonstrated before, has not existed before, and so I think the biggest challenge of the feasibility study is to identify the performance metric to quantify the effectiveness of the motor neuroprosthesis in the study to come.”

In order to assess the aims of the COMMAND study, researchers will be recording shifts in frequency when patients attempt to move their arms or legs, translating these shifts into outputs that become digitised. These digitised outputs, Oxley explains, will then be used to control technology platforms like Google, Microsoft, and Amazon, to enable patients who are paralysed to region control over those systems.

Oxley specifies that the team is focusing initially on paralysis and then epilepsy, but that ultimately “all deep brain stimulation targets should be accessible”.

“We can access all regions of the brain”: Expanding neurointervention horizons

“The most exciting aspect of the emergence of neurointerventional electrophysiology is that we can access all regions of brain,” Oxley remarks, adding that once the technology is small enough and safe enough, he sees a future where the neurointerventionists are placing multiple devices inside the brain.

Thomas Oxley

In addition, Oxley predicts a change in who will deliver such a treatment, seeing in the future a neurointerventional electrophysiology room and not just a typical neurointervention suite.

Concluding, Oxley believes that the development of BCI technology and the “incredible amount of information” it will provide should help to address unanswered questions across many areas—from epilepsy and movement disorders to depression and sleep. “I think there is going to be a whole new world opened up of therapies that have only been in the domain of the craniotomy, but now we can bring that into a minimally invasive approach. We are starting to help patients in ways that we did not think were possible.”

Issue 43 | September 2021

Healthcare Settings 11

Postoperative admission of adult craniotomy patients to neuroscience ward reduces length of stay and costs Admitting adult craniotomy patients without significant comorbidities, who are expected to have a short length of stay, to the neuroscience ward has been associated with shorter stays and a reduced total cost of admission—with no significant differences in postoperative clinical outcomes. This is according to a retrospective analysis published in Neurosurgery.

IN THEIR REPORT, WON KIM (Department of Neurosurgery, Ronald Reagan UCLA Medical Center, David Geffen School of Medicine at UCLA, Los Angeles, USA) and colleagues state that the neurointensive care unit (NICU) has traditionally been the default recovery unit after elective craniotomies, but add: “Our data suggest that even a single-night stay in the NICU was associated with increased overall hospitalisation cost and length of stay, but with no difference in clinical outcome (return to ED [emergency department], return to OR [operating room], and readmission within 30 days).

“The biggest contributor to this difference was the NICU’s base cost.

Our data imply that adult patients without significant comorbidities and with an expected short length of stay who undergo elective craniotomy for supratentorial lesions may be safely

admitted to a neuroscience ward unit without significant additional risks to the patient, while shortening their length of stay and reducing hospitalisation cost.

Early recognition of this patient group and establishment of alternative pathways to ICU [intensive care unit] admission might decrease ICU utilisation, and the cost of hospitalisation.”

The researchers initiated a costeffectiveness analysis of their own institutional experience over a fiveyear period to compare patients who recovered in the NICU versus the neuroscience ward following an elective craniotomy for tumour resection—the first time an analysis of a large series of patients such as this has been reported. They included all elective supratentorial craniotomy patients aged 18 years

Innovative Tools for Neurovascular Interventions

or older, with a length of stay of seven days or less, who were admitted between March 2013 and April 2018.

A total of 209 patients were admitted to the neuroscience ward, while 340 were admitted to the NICU. Any patient characteristics that may have been potential confounders were mostly comparable between these two groups, Kim et al claim. Their analysis revealed the average length of stay in the neuroscience ward group was 3.046 days, compared to 3.586 days in the NICU group. There was no difference in the expected length of stay between the two groups, Kim and colleagues report. “In our multivariate analysis, postoperative stay in the NICU, even for one night, was independently associated with increased length of stay, but not with expected length of stay,” they state.

In addition, the average total cost of hospitalisation in the NICU group was $3,193.33 more per admission than the total cost observed in the neuroscience ward group ($32,496.41 vs. $29,303.08). The authors note that there was no statistically significant difference in surgery costs between the two groups—indicating that differences in costs were incurred postoperatively.

In a post hoc analysis, the differences in cost between the neuroscience ward Won Kim

and the NICU were greatest when the length of stay was one day, and this effect diminished with increasing length of stay.

In multivariate analyses, neuroscience ward admission was a significant independent predictor for total cost when length of stay was less than two, three, four, and five days—suggesting that, for stays shorter than six days in length, neuroscience ward admission becomes “a strong determinant of total cost irrespective of intrinsic patient factors”.

Kim et al add that an evaluation of clinical outcomes in the neuroscience ward and NICU groups found no statistically significant differences in rates of return to the OR or ED, or readmission within 30 days. However, they also acknowledge several limitations of their study, including its retrospective nature, and a lack of randomisation to either group, multicentre data to reduce institutional bias, or more detailed data assessing patient comorbidities.

They conclude that, in patients with a length of stay shorter than five days, direct postoperative neuroscience ward admission may even be an independent predictor of reduced hospitalisation costs, without significant differences in clinical outcomes. However, commenting on the generalisability of this study in discussion with NeuroNews, Kim tempered this conclusion by stating: “It is truly excellent ward-level care that allows us to use our centre as a surgical step-down unit. As such, these findings may not be translatable to other institutions where this is not the case.”

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September 2021 | Issue 43

14 Interview

Profile

Else Charlotte Sandset Else Charlotte Sandset is a consultant neurologist in the Stroke Unit of the Department of Neurology at Oslo University Hospital, and chair of the Oslo Stroke Research Group (Oslo, Norway). Her research interests include blood pressure management in stroke patients, and she has contributed to several clinical trials, such as the ongoing ParaNASPP (Paramedic—Norwegian acute stroke prehospital project) study—for which she is the co-principal investigator. Sandset is also the current secretary general of the European Stroke Organisation (ESO). She talks to NeuroNews to discuss her career to date, in addition to several key issues in the neurology field right now.

What initially attracted you to medicine, and the field of neurology specifically?

What initially drew me to medicine was the wide range of opportunities a medical degree provides, from rural general practitioner to business careers. After my internship, I was drawn to stroke because it combines the fields of neurology and internal medicine, and I embarked on my PhD project on blood pressure in acute stroke. In Norway, both internal medicine and neurology care for stroke patients, but—after attending the European Stroke Conference in Stockholm in 2009—it was clear that a future career in stroke was as a neurologist.

Who have your mentors been and how have they impacted your career?

I did my PhD with the late Eivind Berge as my main supervisor. Together, we completed a large, investigatorinitiated randomised controlled trial. Eivind was brilliant at creating collaborative networks, which is imperative in order to complete any type of international research, and I am thankful to have had a mentor with this focus.

In addition, I have greatly benefitted from working closely with Philip Bath from Nottingham, UK for most of my career. I wrote in the acknowledgement in my thesis that I was thankful for his “contagious enthusiasm for the field of stroke research”, and this still holds true.

I also spent a year working with Craig Anderson in Sydney, Australia—briefly interrupted by the birth of my son five months into my stay. Apart from the many benefits of working in a much more global environment, Craig challenged me to focus on what research findings really mean in the clinical setting. We are doing research to improve the care of our patients and this is really what matters! The support of Urs Fischer has been invaluable in my career too. He is always supportive, always finds time for a quick chat when needed and has a strong focus on giving people opportunities. Charlotte Cordonnier is another person who I highly value, and who is a fantastic role model for me when it comes to time management and how to focus your career.

What has your experience been as the secretary general of the European Stroke Organisation?

ESO has always been an organisation where I have felt “at home”. For me, ESO is inclusive, dynamic and forward-thinking. Most initiatives are welcomed as long as you are willing to do the work yourself, and there is a strong focus on the next generation. There is still a lot of inequity when it comes to stroke care in Europe, and in order to further improve care for our patients we need good clinicians and scientists on board. The best way to achieve that is to provide opportunities for growth for junior colleagues and to enable new voices within the organisation. These are two of the core values of ESO, and I think both are important for success as an organisation. This has become even more evident for me as the secretary general. In all areas of my career, I hope I am smart enough to step aside at the right time and let

others access the many great opportunities I have received.

How has COVID-19 affected your work at the ESO—and in particular the upcoming ESO conference?

COVID-19 has obviously meant a lot less face-to-face interaction, and we will now host our second virtual conference. I think we all miss discussing the latest trial results over the coffee breaks with random conference participants, so we have worked to create an arena for live networking and discussions—also virtually. I am also worried about how this affects younger colleagues especially, with less abstracts being submitted, very few live platform presentations with questions, and, obviously, less opportunity to network with senior colleagues who may enable visiting fellowships or other career opportunities.

There are without a doubt some beneficial aspects as well. The virtual environment has normalised having a family. I do not think we have had a single ESO Executive Board meeting without at least one child showing up—my personal highlight was perhaps my five-year-old Ferdinand dressed up as Kai from Ninjago. As a clinician, I have greatly appreciated the sense of international community and discussions on how to provide adequate stroke care in the pandemic. It became obvious to me during the first wave that, if we do not fight for our stroke patients, no one will!

As a role model, I think it is important to show that it is possible to be a mother, a clinician and a scientist.”

What do you feel has been the most important development in the field of neurology during your career?

The implementation of endovascular therapy worldwide is by far the most important development during my career. Stroke is now established as one of the most time-urgent medical emergencies. Apart from stroke, advances in the treatment of multiple sclerosis have been a game-changer in neurology as well.

Besides your own work, what is the most interesting piece of neurology research you have seen in the past year?

It was a bit further back than the past year, but Adrian Parry-Jones’ “Bundle of Care” approach to the treatment of intracerebral haemorrhage (ICH)—published in the Annals of Neurology in 2019—really caught my attention. We are currently working on a similar protocol

to implement in my hospital, and we have a long way to go to improve care for ICH patients.

What is the most significant unmet need in the field right now?

Without a doubt, treatment of ICH is a key unmet need.

It is one of the most devastating types of stroke and, currently, we are nowhere near the treatment options we have for ischaemic stroke. Also, stroke being a very heterogenous disease. We need to identify more individualised treatments; in the acute setting, and in rehabilitation and secondary prevention.

Throughout your career, what work have you undertaken to improve the representation of women in the neurology field?

I have been involved in the Women Initiative for Stroke in Europe (WISE). As a scientist, I find it difficult

Issue 43 | September 2021

Interview 15 to make statements without having the numbers. In 2018, we published a paper showcasing the number of women in all core activities in ESO. In addition, I have organised Women in Stroke Leadership workshops. Finally, by taking on senior roles within the organisation, you automatically become a role model, and you have an obligation to promote and sponsor good women within the community. As a role model, I think it is important to show that it is possible to be a mother, a clinician and a scientist. You do not fall off the face of the earth because you have children.

How would you assess the issue of gender differences in stroke and stroke care right now—why is this an important area, and what do you think needs to be done to address this?

The majority of evidence in cerebrovascular and vascular medicine in general is generated from white, middle-aged, middle-class men. Generalisability of treatment effects and potential differences in treatment effects is an issue. To address this, we need to ensure representative inclusion of both sexes in trials, and we need a better understanding of why women are underrepresented in most clinical trials.

What advice would you give to people embarking on a career in the field of neurology?

Number one: get involved in clinical research!

Understanding and knowing the evidence provides confidence in your clinical decision-making, and also when you treat beyond evidence-based medicine.

Number two: there are lessons to be learned from everyone you meet. Always focus on the strong traits of your mentors, seniors and colleagues, and learn from them and incorporate them in your own practice.

Number three: find an early interest in neuroradiology.

You will spend a lot of your career looking at images of the brain.

alisonlang.com

What are your interests outside of the field of medicine?

Very few things beat a day with perfectly tuned sails on a sailboat, either on a family trip with my husband and five-year-old son, or more rough sailing with my husband either in a regatta or just for fun. I also find cooking extremely relaxing, and I tend to provide friends and colleagues from around the world with pictures of favourites including sourdough bread and a variety of sweet rolls. Hopefully, I will be able to serve them all the real stuff soon enough! Irrespective of activity, I (nearly) always listen to music and I pretty much enjoy every genre depending on my state of mind.

I am quite sure some of my papers should have had the soundtrack as a disclosure—especially when I revert to German and Swedish “Schlagers”, or Eurodance from the late 90s and early 00s!

Fact file Current appointments:

2008–2012: PhD, Institute of Clinical Medicine, University of Oslo, Oslo, Norway. Thesis title: “Blood Pressure Lowering Treatment in Acute Stroke” 2019: Specialist in Neurology, The Norwegian Directorate of Health, Oslo, Norway

Education:

2015–2016: Visiting fellow, The George Institute for Global Health, Sydney, Australia 2019–present: Secretary general,

2018–present: Senior consultant, Department of Neurology, Stroke Unit, Oslo University Hospital, Oslo, Norway Senior researcher, Norwegian Air Ambulance Foundation, Lørenskog, Norway 2000–2006: MB, BCh, BAO, Royal College of Surgeons in Ireland, Dublin, Ireland

Honours (selected):

European Stroke Organisation (ESO) 2020–present: Chair, Oslo Stroke Research Group, Oslo University Hospital, Oslo, Norway 2021: Chair, ESO Guidelines on Blood Pressure Management in Acute Ischaemic Stroke and Intracerebral Haemorrhage

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Issue 43 | September 2021

Stroke Care 17

Time is brain: Travelling stroke teams enable faster treatment and better patient outcomes

In a pilot programme conducted in New York, USA, a mobile interventional stroke team (MIST) travelled directly to stroke patients to perform emergency surgery instead of transferring them to a specialised stroke centre. This resulted in significantly less disability for patients three months after their stroke when compared to patients who lost valuable time in being transferred— according to findings published in Stroke.

IN THIS STUDY, STROKE SPECIALISTS AT Mount Sinai Health System in New York developed a MIST model to bring endovascular thrombectomy to the patient. The MIST team was staffed with a neurointerventionist, a fellow in training or physician’s assistant, and a radiologic technologist, and travelled to the patient’s location to perform an endovascular thrombectomy procedure.

An American Heart Association (AHA)/American Stroke Association (ASA) press release states that, since

2015, thrombectomy has been the standard of care for acute ischaemic stroke patients—but the biggest barrier these patients face is timely access to the procedure.

“Fewer than 50% of Americans have direct access to endovascular thrombectomy—the others must be transferred to a thrombectomy-capable hospital, often losing more than two hours of time to treatment,” said Johanna T Fifi, co-author of the study, and associate professor of neurosurgery, neurology and radiology in the Department of Neurosurgery at Mount Sinai’s Icahn School of Medicine in New York, USA. “Every minute is precious in treating stroke, and getting to a centre that offers thrombectomy is very important. The MIST model would address this by providing faster access to this potentially lifesaving, disability-reducing procedure.”

Fifi and colleagues examined data from the New York-based MIST trial, which focused on 226 stroke patients who received thrombectomy from January 2017 to February 2020 at four hospitals—one certified comprehensive stroke centre and three thrombectomy-capable stroke centres— within the Mount Sinai Health System. Of those, 106 patients were treated by the MIST team, and 120 were treated using the drip-and-ship model of care, which requires the patient to be transferred to a hospital with expertise in endovascular thrombectomy. All patients

Return to work and depressive symptoms in young stroke survivors Matthias Volz Simon Ladwig Katja Werheid Comment & Analysis Matthias Volz (University of Kassel, Kassel, Germany), Simon Ladwig and Katja Werheid (both Humboldt-Universität zu Berlin, Berlin, Germany) discuss the burden of post-stroke depression (PSD), and how this complication impacts the re-integration of stroke survivors back into their social and working life.

D

epression is a frequent complication of stroke, affecting about one third of stroke survivors within the first year.

PSD is known to impair a stroke patient’s recovery process, which leads to longer hospitalisation and poorer social re-integration. Moreover, stroke survivors with PSD are less likely to participate in rehabilitation measures and are also less likely to return to work after stroke. Recent systematic reviews summarising almost 50 years of research have identified five major risk factors for PSD: prior episodes of depression, impaired functioning in activities of daily living, higher stroke severity, cognitive impairment, and self-perceived social support.

The average working age is extending all the time due to higher life expectancy, and the prevalence

of ‘lighter’ stroke is increasing due to substantial improvements in acute stroke management. As a consequence, the focus of stroke rehabilitation programmes increasingly shifts from the recovery of basic functionality after mere survival and the subsequent training of daily activities towards re-integration of stroke survivors back into their social and working life. Furthermore, stroke increasingly affects younger people, leading to an even higher number of stroke survivors amidst their careers— often with high demanding social and financial responsibilities for themselves and their loved ones.

Return to work (RTW) after stroke is a central benchmark for most stroke survivors in their working age. RTW is most likely to be achieved within the first year after stroke, and, more specifically, in the second half of this first

< 50%

in the analysis were functionally independent before having a stroke. The researchers compared 90-day functional outcomes between patients treated by MIST and those transferred to a stroke centre. Using the modified Rankin Scale (mRS) and the National Institutes of Health Stroke Scale (NIHSS) to assess outcomes, they analysed results from patients who were seen within six hours of stroke-symptom onset and more than six hours after stroke symptoms.

For patients treated within six hours of stroke onset, the rate for a good outcome—an mRS score less than or equal to two—three Fewer than 50% of Americans months after the event was have direct access significantly higher in patients to endovascular from the MIST group (54%) thrombectomy compared to the transferred group (28%).

Among patients treated within six hours, functional outcomes at discharge were significantly better in the MIST patients than the transferred patients too. For patients treated after more than six hours, outcomes were similar, with 35% of patients in the MIST group having a good 90-day outcome compared to 41% in the transferred group.

While this study’s findings are limited by its nonrandomised nature and retrospective analyses, Fifi added that “the MIST approach to care continues, as more institutions and cities have implemented the model”.

year. During this phase, most patients have returned home after receiving continuous and intensive care in the safety of rehabilitation facilities. This re-integration, back into a familiar environment, and into the same or an altered working environment, is a fragile segment of stroke survivors’ recovery process. Without sound anticipation and mitigation of potential barriers during these rehabilitation programmes, stroke survivors may face severe challenges just when they do not have direct access to the interdisciplinary resources of the care chain.

Despite the significance of RTW and its growing relevance due to extended working age, RTW is often not routinely assessed in younger stroke survivors.

In fact, younger stroke survivors still pose an underrepresented group in stroke trials, which means that existing stroke rehabilitation guidelines often do not consider their specific needs.

Consequently, little is known about the association of RTW and PSD—RTW may be hampered by PSD and by the major five risk factors. Once achieved, RTW may, however, also reduce depressive symptoms.

In our study, we approached this hen-and-egg question with scientific tools. A sample of about 170 ‘light’ stroke survivors in their working age (<65 years) and with employment before stroke was recruited from two stroke rehabilitation clinics. The sample was assessed for the five established risk factors shortly after stroke: pre-stroke depression, activities of daily living, stroke severity, cognitive impairment, and social support. Employment status (RTW) and depressive symptoms were assessed by telephone interviews six and twelve months post-stroke. Multivariate regression analyses were used to

assess the effect of RTW on depressive symptoms, while statistically controlling for the five other PSD risk factors.

The results showed that, after six months, successful RTW, absence of depressive episodes prior to stroke and higher perceived social support were independently associated with lower depressive symptoms. Most importantly, this association of RTW and depressive symptoms was independent of the other factors. Additionally, stroke survivors with successful RTW after six months were less likely to report subsequent depressive symptoms 12 months after stroke, indicating a protective effect of RTW on subsequent mental health.

Our results, which should be replicated and extended in larger samples, underline the importance of re-integration into work life early after stroke with high priority. Professionally supported retraining programmes and, if necessary, opportunities on the secondary job market should be fostered. These measures may not only bear direct economic benefits, but also improve mental health of persons with stroke and reduce the burden of their relatives.

Healthcare means much more than saving lives and brain tissue—we should support working age patients in giving their everyday life a meaning.

Matthias Volz is a researcher in the Department of Psychology at the University of Kassel in Kassel, Germany.

Simon Ladwig is a researcher in the Department of Psychology at HumboldtUniversität zu Berlin in Berlin, Germany.

Katja Werheid is professor for clinical neuropsychology and researcher in the Department of Psychology at HumboldtUniversität zu Berlin in Berlin, Germany.

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Issue 43 | September 2021

Study indicates clinical benefit of nonparaesthesia-based approaches in burst SCS lead placement Continued from page 1

base for many more robust and adequately powered studies in the future. Such studies can lead to new frontiers in SCS therapy, in addition to strengthening the existing findings.”

In their report, Al-Kaisy et al note that conventional SCS—an established and effective therapy for chronic intractable pain—involves electrode placement based on intraoperative paraesthesia mapping, but that newer paradigms like burst SCS may allow for an alternative approach to lead placement based on anatomic landmarks. “The anatomic placement approach does not require iterative intraoperative feedback from the patient and may provide two important advantages in the intraoperative setting,” they state. “First, anatomic placement may aid in situations where patient reporting may be compromised by anaesthesia or medications, anxiety, acute discomfort, and/or surgical positioning.

Another potential advantage may be shorter procedural time or operating time.”

In order to investigate how this more novel approach compares to paraesthesia mapping, the prospective, multicentre, randomised, double-blind, crossover CRISP study was devised to assess the safety and efficacy of both. It was conducted at two centres in the UK between 2016 and 2019, and involved placement of a relatively recent introduction to the field of SCS—the BurstDR stimulation system (Abbott). Adult patients of both genders with a diagnosis of failed back surgery syndrome and an intractable chronic lower back pain with an intensity of at least 60 out of 100mm on a visual analogue scale (VAS) were recruited from the investigators’ clinical practices, according to Al-Kaisy and colleagues.

Eligible patients were implanted with two leads— with the first lead being placed to cross the T8/T9 disc, and active contacts for this lead being chosen through paraesthesia mapping. The second lead was placed at the T9/T10 spinal anatomic landmark. Patients initially underwent a four-week, double-blinded, crossover trial with a two-week testing period with burst SCS delivered through each lead in a random order. At the end of the trial period, they expressed their preference for one of the two leads, and subsequently received burst SCS with the preferred lead and were followed up at three, six and 12 months. Pain intensity assessed via VAS, quality of life measured with the EuroQol-5D instrument, and disability ascertained through the Oswestry Disability Index (ODI), were evaluated at baseline and follow-up.

The primary endpoint of the study was to evaluate changes in back pain, leg pain, daily overall pain, and worst daily intensity—relative to baseline—for the two lead placement groups at the end of the trial, Al-Kaisy and colleagues note, while secondary endpoints of the study included comparison of patient preference for lead implantation techniques, evaluations of changes in pain intensity, quality of life and disability, and evaluation of patient treatment satisfaction through a seven-item questionnaire. Adverse events reported over the course of the study were also recorded descriptively.

The authors report that a total of 43 patients achieved at least a 50%

19 reduction in back pain at the end of the trial’s evaluation phase and continued into the follow-up phase, with 21 (48.8%) expressing a preference for paraesthesia mapping and 21 (48.8%) preferring anatomic placement.

One patient (2.4%) had no preference and, therefore, the anatomic lead was used during the follow-up phase, Al-Kaisy et al add. They also note that there was “no obvious difference in subject group demographics based on lead preference”, while pain scores—for both back and leg—significantly improved from baseline for both groups at all follow-up time points, with no significant between-group differences.

Significant improvements in terms of quality of life and disability were observed too, and, at 12-month follow-up, 94% of the patients who used the anatomic placement lead and 85% of the patients who used the paraesthesia mapping lead were reported to be either satisfied or very satisfied. Regarding safety outcomes, a total of 58 adverse events were reported in 24 patients.

Of those events, seven were serious, 33 were nonserious—and most commonly consisted of headaches, pain at the implantable pulse generator (IPG) site, IPG unpairing, leakage at the wound site or IPG scar, and irritation around the surgery site—and the remaining 18 events were not classified. There were no deaths, or unanticipated serious adverse device effects or device deficiencies, reported during the study, the authors state.

“The present study, for the first time in an RCT [randomised controlled trial] framework, compared the long-term effects of a novel paraesthesia-free burst SCS waveform delivered using a lead permanently implanted using paraesthesia mapping guidance with those of a lead implanted with anatomic placement alone,” Al-Kaisy and colleagues write. And, regarding the fact that 21 patients expressed a preference for the former approach, and 21 expressed a preference for the latter, they add that “such an even distribution of preferences would be expected if both implantation techniques provided equivalent pain relief and reduction of associated disabilities”.

“Given the equivalent outcomes demonstrated in this study and the unique considerations with both lead implantation strategies, physicians can choose the most appropriate lead implantation strategy when

The results exhibit the feasibility of anatomic placement as a procedure that can potentially establish a more streamlined and time-efficient treatment continuum with minimal patient discomfort.”

Adnan Al-Kaisy et al

employing the burst mode of SCS, depending upon the patient characteristics and/or circumstances,” they continue, noting that the “relative simplicity and reliability of anatomic lead placement” may be useful in situations where patient reporting is compromised, or in reducing patient discomfort and stress. On the other hand, the authors note, paraesthesia mapping could still be employed, for example, to ensure full recruitment of the dorsal column afferents corresponding to the painful area—whereas combining it with burst mode can largely prevent the perception of extraneous paraesthesia coverage during intraoperative testing.

Adnan Al-Kaisy

Temporary SCS could represent “new paradigm” in preventing atrial fibrillation In a randomised pilot study, temporary spinal cord stimulation (SCS) has demonstrated efficacy in the suppression of postoperative atrial fibrillation (AF) following coronary artery bypass graft (CABG) surgery, resulting in a lower burden of AF in comparison with patients receiving standard medical therapy.

Temporary SCS also demonstrated a “good safety profile” in the study.

Atrial tachyarrhythmia occurrence rate at 30 days =

3.8%

T

with CABG plus SCS

30.2%

with CABG alone

his is according to data from a late-breaking abstract presentation at this year’s Heart Rhythm Society annual meeting (HRS 2021, 28–31 July, Boston, USA and virtual), which saw Alexander Romanov, head of the Center of Invasive Electrophysiology at the Ministry of Health’s Meshalkin National Medical Research Center in Novosibirsk, Russia, detail 30-day safety and efficacy outcomes from a first-in-man, randomised pilot study of early, perioperative SCS to prevent post-CABG AF. The prospectively defined primary safety endpoint of the study, Romanov stated, was occurrence of adverse events including death, stroke or transient ischaemic attack (TIA), myocardial infarction (MI), and kidney or spinal cord injury, while the primary efficacy endpoint was occurrence of AF or any atrial tachyarrhythmias lasting more than 30 seconds. Both were tested for over the course of the 30-day postoperative period.

A total of 52 patients, with a mean age of close to 60 years, were enrolled in the trial and randomised into two groups, with 26 receiving SCS plus standard medical therapy following CABG—that being a beta blocker medication—and 26 receiving standard medical therapy alone. Romanov noted that patients in the prior group began receiving SCS three days before CABG surgery and stopped receiving it seven days post-surgery—with the therapy also being deactivated during the surgery itself.

The study met its primary safety endpoint, as no occurrences of the above adverse events were seen in either group at 30 days. In addition, at the 30day follow-up timepoint, standard medical therapy plus temporary SCS resulted in an 89% reduction in the risk of any atrial tachyarrhythmias compared to CABG alone—with p-values suggesting a statistically significant difference between the study groups.

Romanov reported an AF or atrial tachyarrhythmia occurrence rate of 3.8% in the CABG plus SCS group, and 30.2% in the CABG group, adding that the mean AF burden on continuous external electrocardiogram (ECG) monitoring and the median total duration of AF episodes were both significantly higher in the CABG-only group.

Romanov concluded his presentation by stating that, based on these findings, SCS could represent a “new paradigm” for AF prevention—but also requires further investigation via more long-term studies, with one-, three- and five-year follow-up now planned in the current study too.

September 2021 | Issue 43

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High-frequency SCS takes the stage to relieve chronic pain from diabetic neuropathy Erika A Petersen Comment & Analysis Following the recent approval of the Senza system (Nevro) by the US Food and Drug Administration (FDA), Erika A Petersen (Little Rock, USA) discusses the impact of the only spinal cord stimulation (SCS) device indicated to treat chronic pain associated with painful diabetic neuropathy (PDN) in the USA.

F

or more than three decades, spinal cord stimulation (SCS) has been recognised as a reliable tool to manage chronic pain when simpler treatment routes fail to elicit a satisfactory response. Not surprisingly, the therapy has seen a number of evolutions since it was first introduced, including innovations designed to overcome some imperfections associated with earlier technology.

One such advancement, a highfrequency SCS system with strong clinical evidence of efficacy, recently received FDA approval for a specific indication to treat people with PDN. Nevro’s HFX for PDN—a comprehensive solution that includes a Senza SCS system and supporting services for the treatment of chronic pain—is the only SCS solution to be FDA-approved to treat the condition, which is often characterised by persistent numbness, pain, and tingling in the hands and feet.

High-frequency SCS

Most SCS systems deliver stimulation using waveforms in the 60–1000Hz frequency range, which create a tingling sensation known as paraesthesia to distract the patient from their pain. While paraesthesia can be helpful for some people, there are many who report the tingling feeling to be uncomfortable.

For example, a person with PDN who already has severe tingling in their feet certainly would not want more tingling.

To avoid this, HFX uses imperceptible pulses at a higher frequency of 10kHz. This high frequency waveform relieves pain without the sensation of tingling, or pins and needles, and its effectiveness has been shown in randomised controlled trials (RCTs) for treatment of chronic back and leg pain.

For patients who find other waveforms bothersome, 10kHz stimulation without paraesthesia has distinguished itself as a true therapy differentiator among SCS

Antibiotic impregnated envelopes appear to be a safe and effective modality for decreasing surgical site infection risks in spinal cord stimulation (SCS) implantation, according to study data published in Journal of Pain Research.

THE REPORT, WHICH IS AUTHORED BY Jonathan M Hagedorn (Department of Anesthesiology and Perioperative Medicine, Division of Pain Medicine, Mayo Clinic, Rochester, USA) and colleagues, states that surgical site infections in patients who undergo spinal cord stimulator implantation represent a “significant concern in terms of increased healthcare costs and patient morbidity”—but that the use of antibacterial envelopes to minimise this risk has not

The SENZA-PDN trial

The SENZA-PDN RCT is the largest RCT to date conducted to study SCS treatment for PDN. Study participants demonstrated significantly improved and sustained outcomes with 10kHz therapy (HFX for PDN). People who received the 10kHz therapy in the trial experienced a 76% reduction in PDN pain, versus −2% for patients with conventional medical management (CMM) alone. Physicians observed that 62% of patients treated with 10kHz therapy had improved motor, reflex, and sensory function on neurological examinations, versus 3% of the patients treated with CMM alone.

These patients also reported decreases in uncomfortable sensations, including

With 10kHz SCS, we have a chance to give people their lives back.” burning, numbness, tingling, and cold.

My co-investigators and I were intrigued and inspired by the results of our study and—more importantly—what it suggests for people who have and who will eventually endure debilitating symptoms from PDN. As the prevalence of diabetes continues to rise, so does the number of people with complications like PDN. Many people with the condition struggle to achieve pain relief from traditional treatments, such as over-the-counter and prescription medications. I have had patients confide in me that the side-

been previously described.

As such, Hagedorn et al conducted a retrospective review to evaluate this approach and its effectiveness when used adjunctively to standard infection prevention measures. The study included 52 patients (average age=62.2 years, 51.9% female), all of whom were implanted with a spinal cord stimulator between January 2015 and November 2020, and had the single-use, multifilament mesh TYRX absorbable antibacterial envelope (Medtronic) utilised at the time of surgery.

Data were collected and analysed on 52 permanent SCS implantations, which included 26 primary implantations and 26 revision surgeries. All patient data were collected at least three months postoperative from their implant surgery, while the average follow-up time period was 518.4 days. Hagedorn and colleagues report that there were no surgical site infections reported in the 52-patient cohort. Additionally, the authors state that there were no

52 26 26

➔

Antibiotic envelopes appear safe and effective in decreasing SCS surgical site infection risks

devices. I was keen for the opportunity to test the paraesthesia-independent efficacy of 10kHz SCS for PDN and to explore whether it would prove successful in treating my PDN patients.

ZERO

52 permanent SCS implant procedures 26 primary implantations and 26 revision surgeries.

Resulted in zero reported surgical site infections

effects elicited from their prescription medications are so burdensome that they would prefer to endure PDN without the medication. Others are frustrated that they are chasing relief with higher doses of medication and less relief over time.

New era in PDN therapy

The FDA approval of this SCS device marks a monumental shift for people with PDN and the physician teams committed to treating them. The feeling of defeat when we have explored all available avenues for relief, yet significant and disruptive pain remains, may be no longer. With 10kHz SCS, we have a chance to give people their lives back.

We are giving them the little moments, like working or playing with grandkids, and the big moments, like walking their daughter down the aisle on her wedding day. We are getting them more restful nights. These moments add up to a more meaningfully engaged life, and there are few things more rewarding than that.

References: 1. Petersen E A, Stauss T G, Scowcroft J A, et al. Effect of High-frequency (10-kHz) Spinal Cord Stimulation in Patients with Painful Diabetic Neuropathy: A Randomized Clinical Trial. JAMA Neurol. 2021;78(6): 687–98.

Erika A Petersen is a board-certified neurosurgeon, professor in the Department of Neurosurgery at the University of Arkansas for Medical Sciences (Little Rock, USA), programme director for the Neurosurgery Residency and director of the Section of Functional and Restorative Neurosurgery.

Her clinical practice focuses on neuromodulation, treating movement disorders, spasticity and chronic pain through surgical procedures and stereotactic radiosurgery.

Disclosures: The author served as the principal investigator on the SENZAPDN randomised controlled trial, and as such received funding from Nevro. surgical complications encountered from the use of the antibacterial envelope, including delayed or interrupted wound healing, skin irritation, allergic reactions, seroma or haematoma formation, or increased postoperative pain.

“The results presented in this retrospective review suggest that use of an absorbable antibacterial envelope may be effective in reducing the risk of surgical site infection in primary and revision SCS implant surgeries,” the authors conclude. “Additionally, careful assessment of comorbid perioperative risk factors may play a crucial role when establishing interventions for infection prevention.

“Implantation of SCS therapies is rising, and the surgical volume is projected to continue on an upward trajectory as new indications and technologies emerge.” Hagedorn et al add that understanding and mitigating surgical complications like surgical site infection to the maximal degree possible is “essential for the continued success of the field”.

Issue 43 | September 2021

21

Ultra-thin, inflatable device may overcome limitations seen in current SCS technologies A team of engineers and clinicians from the University of Cambridge in Cambridge, UK has developed an ultra-thin, inflatable spinal cord stimulation (SCS) device that can be used to treat the most severe forms of pain without the need for invasive surgery.

The device uses a combination of soft robotic fabrication techniques, ultra-thin electronics and microfluidics.

IT IS ABOUT THE WIDTH OF A HUMAN HAIR, and can therefore be rolled up into a tiny cylinder, inserted into a needle, and implanted into the epidural space of the spinal column. Once correctly positioned, the device is inflated with water or air so that it unrolls like a miniature air mattress, covering a large section of the spinal cord. And, when connected to a pulse generator, its ultra-thin electrodes begin sending small electrical currents to the spinal cord to disrupt pain signals.

Early tests of the device suggest that it could be an effective treatment for many forms of severe pain— including leg and back pain—which are not remedied by painkillers. It could also be adapted into a potential treatment for paralysis or Parkinson’s disease, according to a University of Cambridge press release, although extensive tests and clinical trials will be required before the device can be used in patients.

While other types of SCS device are currently used to treat severe pain, the most effective of these devices are bulky and require invasive surgery, while current keyhole devices are far less effective at treating pain. By combining the clinical effectiveness of the former with the ease of implantation of the latter, the

Cambridge-developed device could be an effective, long-term solution to intractable pain. The results of a recent study investigating the device are reported in the journal Science Advances.

Our goal was to make something that is the best of both worlds—a device that is clinically effective, but does not require complex and risky surgery.”

Christopher Proctor

“SCS is a treatment of last resort, for those whose pain has become so severe that it prevents them from carrying out everyday activities,” said Damiano Barone from the Department of Clinical Neurosciences at the University of Cambridge (Cambridge, UK), who

is also one of the paper’s senior authors. “However, the two main types of SCS devices both have flaws, which may be one reason their use is limited, even though millions struggle with chronic pain every day.”

“Our goal was to make something that is the best of both worlds—a device that is clinically effective, but does not require complex and risky surgery,” said Christopher Proctor from the university’s Department of Engineering, who is the paper’s other senior author.

“This could help bring this life-changing treatment option to many more people.”

The researchers used a combination of manufacturing techniques to build their device: flexible electronics used in the semiconductor industry; tiny microfluidic channels used in drug delivery; and shape-changing materials used in soft robotics. Their finished device is just 60 microns thick—thin enough that it can be rolled up and placed in a needle for implantation. However, after implantation, the device expands out to cover a wide area of the spinal cord thanks to its microfluidic channels.

“Thin-film electronics are not new, but incorporating fluid chambers is what makes our device unique—this allows it to be inflated into a paddle-type shape once it is inside the patient,” said Proctor. The researchers validated their device in in vitro tests and on a human cadaver model. They are currently working with a manufacturing partner to further develop and scale up their device, and are hoping to begin tests in patients within two-to-three years.

“The way we make the device means that we can also incorporate additional components,” Barone added. “We could add more electrodes or make it bigger in order to cover larger areas of the spine with increased accuracy.

This adaptability could make our SCS device a potential treatment for paralysis following spinal cord injury or stroke, or movement disorders such as Parkinson’s disease. An effective device that does not require invasive surgery could bring relief to so many people.”

A specialised news source in the spinal arena A trusted provider of latest news, review of cutting-edge research, congress coverage and opinion from thought leaders Editorially independent

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September 2021 | Issue 43

22

DTM SCS gives patients and physicians a unique, tailored, and highly effective treatment option for back pain Michael Fishman Comment & Analysis Michael Fishman (Wilmington, USA) discusses the benefits of Differential Target Multiplexed spinal cord stimulation (DTM SCS; Medtronic)—when compared to more conventional SCS therapies— and how this novel approach is driving an evolution in treatment paradigms for chronic low back pain.

A

lthough the inflammatory neuroglial interaction involving both microglial and neuronal cells plays a central role in the development and persistence of pain, SCS has not historically studied the role of glial cells in pain modulation, and has instead focused almost entirely on mechanisms related to neurons.

Similarly, SCS research has traditionally not focused on describing the impact on underlying inflammatory processes or gene expression changes.

Preclinical research has led to advances in our understanding of gene expression patterns in glial and neuronal cells, as well as of the interactions between glial and neuronal cells that contribute to pain. This work, in turn, is creating the foundation for new interventions that, in a clinical trial, have shown significantly improved efficacy in treating chronic pain.

DTM SCS therapy

DTM SCS therapy is prescribed for patients with chronic low back and leg pain. It targets different areas of the spinal cord—hence, Differential Target— with different signals or frequencies— hence, Multiplexed. With DTM SCS, therapy and settings can be customised to address each patient’s individual needs.

In a randomised controlled trial (RCT), DTM SCS therapy was shown to provide profound back pain relief (≥80%) and significant reductions in leg pain for patients with chronic pain at 12 months.

This study also showed that DTM SCS therapy was superior to conventional SCS with respect to back pain relief.

It has been known for more than 20 years that glial cells outnumber neuronal cells in the spinal cord by a ratio of 12:1. And, while SCS has historically been designed with a neuronal target in mind despite this knowledge, more recent investigations have shown that the use of customised waveforms— hypothesised to differentially target neurons and glial cells—can provide

therapeutic benefit. DTM SCS therapy is the only neuromodulation approach that has shown, in animal models, robust modulation of both of these key cell types.

Additional preclinical studies have shown that chronic pain is associated with changes in a variety of gene expression patterns and that DTM SCS shifts expression back toward pre-pain levels more effectively than high- or low-rate SCS. With a mechanistic approach hypothesised to address the underlying biology of pain, DTM SCS therapy is a novel approach that warrants incorporation into standard clinical practice for appropriate patients.

Impact of SCS on gene expression patterns

Animal models of pain (spared-nerve injury [SNI] and chronic constriction injury [CCI]) show genomic changes that are related to injury and presumed to be related to pain. Genomic analysis of the effect of conventional SCS in uninjured and SNI animal models identified genetic changes associated with injury and with SCS in both the spinal cord and dorsal root ganglion (DRG). For example, RNA-seq analysis in nerve-injured rats with or without repetitive, conventional SCS identified a potential relationship between specific genes and the therapeutic effects observed in animals undergoing conventional SCS after CCI. Similarly, genomic analysis of the effects of 72 hours of continuous SCS in a non-pain animal model identified specific gene expression changes in both the spinal cord and DRG. Changes in gene expression patterns have also been identified in M1 and M2 glial cells following SNI, and high- and low-rate SCS had differential effects on shifting these patterns to a pain-naïve state.

DTM SCS therapy was also investigated in these animal models and demonstrated a greater ability to rebalance neuron/glial gene expression patterns compared to high- or low-rate

SCS alone. Single-cell RNA-seq in animals with and without nerve injury, and pre- and post-SCS, found that SNI creates an imbalance in inflammatory response for neurons and microglia—and that DTM SCS therapy: ■ Was more effective than high- or lowrate SCS at rebalancing neuron and microglial inflammasomes ■ Affected a population of inflammation genes in neurons and microglia that were unaffected by high- or low-rate SCS ■ Was more effective than high- and low-rate SCS in relieving mechanical hypersensitivity A preclinical study evaluating the effect of DTM SCS therapy found that it significantly improved hot and cold sensitivity in an SNI animal model and, in specific neural tissue cell populations, showed a more significant shift to a pre-injury gene expression pattern in microglia, astrocytes, oligodendrocytes and neurons compared with high- or lowrate SCS.

DTM SCS trial results on Intellis platform

DTM SCS therapy has been evaluated in an RCT in which 128 subjects were randomised to receive either DTM SCS or conventional SCS therapy. Subjects in both arms of the study were implanted using the Intellis platform (Medtronic) and followed over the course of 12 months. At 12 months, 84% of patients with chronic back pain treated with DTM SCS reported at least 50% pain relief, compared to 51% of patients treated with

With a mechanistic approach hypothesised to address the underlying biology of pain, DTM SCS therapy is a novel approach that warrants incorporation into standard clinical practice for appropriate patients.” conventional SCS, as measured by the widely used visual analogue scale (VAS) for pain intensity. Some 69% of patients were profound back pain responders (>80% improvement) at 12 months with DTM SCS therapy, compared with only 35% with conventional SCS. Additionally, patients in the DTM SCS therapy arm had an average back VAS score reduction of 75%, compared with 50% for conventional SCS. At 12 months, patients in the DTM SCS arm had a mean VAS score of less

than two (1.74), indicating sustained back pain relief, compared with 3.71 for conventional SCS. Similarly, patients in the DTM SCS arm had sustained leg pain relief with a mean VAS score of less than two (1.45) at 12 months, compared with 2.25 for conventional SCS. With these results, the study met its primary endpoint of noninferiority compared with conventional SCS, and a pre-specified secondary statistical test for superiority showed the difference between DTM SCS therapy and conventional SCS was highly significant.

This RCT also demonstrated positive responses to DTM SCS therapy on several secondary outcomes, including sustained improvements in degree of disability and quality of life at 12-month follow-up. In the DTM SCS therapy arm, the percentage of patients with minimal/moderate disability as assessed using the Oswestry Disability Index (ODI) increased from 27% at baseline to 76% at 12 months, while the percentage of subjects with excellent/ very good/good/fair outcomes as assessed by patient-reported outcomes measurement information system (PROMIS) scores increased from 39% to 88%. Additionally, the majority of subjects (83%) in the DTM SCS therapy arm were satisfied or very satisfied with the therapy. The US Food and Drug Administration (FDA) recently approved updated US labelling of the Intellis platform to reflect outcomes from this RCT, which show superior back pain relief when using DTM SCS compared to conventional SCS.

Evolving chronic back pain treatment paradigms

A robust and growing body of preclinical evidence demonstrates that DTM SCS therapy shifts gene expression patterns back toward pre-pain states, and the recently reported RCT data showed a clear, statistically significant benefit for DTM SCS therapy compared with conventional SCS in patients with back pain. The RCT data also showed that DTM SCS therapy provided profound back pain relief in the majority of patients and that patients with “long” pain duration of greater than 12 years, who have likely tried other options for pain relief, achieved pain relief with DTM SCS. Taken as a whole, the data provide a cogent rationale for incorporating DTM SCS therapy into routine clinical practice in patients who may benefit from this novel therapy.

References: References for this article are available online and can be viewed at neuronewsinternational.com/dtm-scs-therapyback-pain-michael-fishman/.

Michael Fishman is an interventional pain medicine specialist at the Center for Interventional Pain and Spine in Wilmington, USA. Disclosures: The author was a principal investigator for the Stimgenics openlabel, post-market study (SGX-SCSRCT), and is a consultant for Medtronic.

Medtronic provided technical support for and reviewed the contents of this article prior to publication.

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Issue 43 | September 2021

Market Watch 25 notification of five minutes and 45 seconds across all of the sites involved when using Viz LVO. In the study, the AI-powered software achieved 96% sensitivity and 94% specificity in identifying LVOs across 2,544 consecutive patients from 139 hospitals.

Product News Nevro announces FDA approval of 10kHz highfrequency SCS therapy for painful diabetic neuropathy

Nevro has announced receipt of US Food and Drug Administration (FDA) approval for its Senza system for the treatment of chronic pain associated with painful diabetic neuropathy (PDN). This approval is specific to the US medical device company’s 10kHz stimulation—making it the only spinal cord stimulation (SCS) system approved by the FDA with a specific indication to treat PDN, a Nevro press release states.

The company will immediately initiate commercial launch activities in the USA under its recently launched HFX branding, as HFX for PDN. In the SENZA-PDN randomised controlled trial, which assessed Nevro’s technology as a treatment option for PDN, study participants demonstrated significantly improved and sustained outcomes with 10kHz SCS including substantial, sustained pain relief and improved health-related quality of life.

The six-month results for the trial were previously published in JAMA Neurology in April 2021, and the 12-month follow-up results and sixmonth crossover patient data were recently presented at the American Diabetes Association 81st scientific sessions (ADA; 25–29 June 2021, virtual).

“The substantial pain relief and improved quality of life demonstrates that 10kHz therapy can safely and effectively treat this patient population,” said Erika A Petersen (University of Arkansas for Medical Sciences, Little Rock, USA), lead investigator of the SENZA-PDN study. “I am grateful to my co-investigators and the patients who participated in this study, as the results and this approval will have a far-reaching impact on the lives of PDN patients.”

Data from the trial will be used to support physician referral decisions as well as market access initiatives to expand payer coverage of this procedure, according to a Nevro press release. The company plans to publish these 12-month results, including the six-month crossover patient data, in a peer-reviewed journal. Study participants will also continue to be followed out to 24 months.

Omniscient Neurotechnology launches Quicktome brainmapping platform following FDA clearance Omniscient Neurotechnology has received US Food and Drug Administration (FDA) 510(k) clearance for Quicktome—a digital brain-mapping platform that allows neurosurgeons to visualise and understand a patient’s brain networks prior to performing life-changing brain surgery. In

Insightec announces approval of Exablate Neuro platform in Singapore

Quicktome

addition to FDA clearance in the USA, Quicktome has also received Health Canada approval as well as regulatory clearance by the Therapeutic Goods Administration (TGA) of Australia.

Quicktome is a neurosurgical planning software that incorporates ‘connectomics’, the field of understanding brain connectivity, into routine neurosurgical planning.

By visualising networks that are responsible for complex functions like language, movement, and cognition, it assists neurosurgeons in making more informed decisions and reduces surgical uncertainty.

By utilising cloud computing for large-volume data processing, and intuitive browser-based interfaces that can be accessed easily on a desktop computer, it is intended to streamline these processes for neurosurgeons. By analysing millions of data points derived from a patient’s magnetic resonance imaging (MRI) scan, the digital platform also enables multidisciplinary collaboration in hospitals, and greater insight before and during surgery.

Viz.ai receives CE mark to bring AI-powered stroke care software to Europe

Viz.ai has been awarded a CE mark for its artificial intelligence (AI)-powered stroke care software—affirming its conformity with regulatory standards in the European Economic Area.

This intelligent system connects multidisciplinary teams earlier, coordinates care and puts patients first with the company’s software suite, which has been clinically proven to synchronise stroke care, decrease time to treatment and greatly improve patient outcomes.

Viz.ai’s flagship solution, Viz LVO, uses AI to automatically detect suspected large vessel occlusion (LVO) strokes on computed tomography angiography (CTA) imaging, and directly alert on-call stroke specialists about potentially treatable patients in a standalone or multi-hospital network.

Faster triage with Viz LVO enables the identification and treatment of more patients who are eligible for thrombectomy, which improves patient outcomes and reduces the chances of long-term disability.

A recent, large, real-world multicentre study found a median time-to-

Insightec has announced approval of its Exablate Neuro platform by the Health Sciences Authority (HSA) in Singapore.

The platform uses focused ultrasound to ablate targets deep in the brain.

This unilateral treatment is suitable for patients with essential tremor who are age 22 or older, or tremor-dominant Parkinson’s disease patients aged 30 or older, who have not responded to medications.

There are 81 leading medical centres globally that have established focused ultrasound programmes with Exablate Neuro. Insightec is working with Transmedic Group, a leading distributor of advanced medical technology in Southeast Asia, to advance adoption of Exablate Neuro in the Singapore market.

Sensome granted FDA Breakthrough Device designation for AI-powered stroke guidewire

Sensome has announced its Clotild smart guidewire system—designed to improve the treatment of ischaemic stroke patients—has been granted Breakthrough Device designation by the US Food and Drug Administration (FDA).

The company’s sensing technology combines impedance-based microsensors with machine learning algorithms to instantly identify biological tissues. In acute ischaemic stroke, the AI-powered Clotild system is designed to provide physicians with critical information on the characteristics of blood clots, enabling them to be removed via mechanical thrombectomy in the fewest number of attempts possible.

As part of the Breakthrough Device programme, the FDA will provide Sensome with priority review and interactive communication on its path from device development to commercialisation. A first-in-human clinical trial of Clotild is also expected to start later this year outside of the USA.

SpinTech earns FDA clearance for rapid, quantitative brain-imaging technology

ReActiv8 system

Mainstay Medical launches implantable restorative neurostimulation system in USA

Mainstay Medical has announced the limited US commercial launch of ReActiv8, its implantable restorative neurostimulation system to treat intractable chronic low back pain— which is now also being made available through ReActiv8-certified physicians.

To support this launch, Mainstay has established a new corporate website centred around patient and physician education, as well as introducing updated tools, guidance, and training materials to assist in identifying prospective patients for ReActiv8 therapy, educating physicians on the ReActiv8 system and becoming ReActiv8-certified, and helping patients access ReActiv8 in the USA. Specific resources include physician training protocols and modules on ReActiv8, educational and marketing collateral, and informative videos that support and further physician education, patient identification, and appropriate product use.

Following this limited US launch, Mainstay plans to expand availability of ReActiv8 over the coming months.

The US Food and Drug Administration (FDA) has granted 510(k) approval for STAGE (Strategically acquired gradient echo), the latest magnetic resonance imaging (MRI) technology developed

by SpinTech.

STAGE is a post-processing software platform that enables comprehensive, quantitative brain imaging with enhanced visualisation in significantly less time than conventional approaches.

It allows MRI technicians to acquire 16 brain-imaging contrasts, including 10 enhanced contrast qualitative outputs and six quantitative outputs, in just five minutes on 3T systems. STAGE is cleared for use on both 1.5T and 3T MRI systems across manufacturers, and runs on existing equipment.

Aside from its enhanced-contrast qualitative outputs, STAGE generates quantitative outputs like T1 and proton density (PD) maps, and is the first 510(k)-cleared product to provide quantitative susceptibility mapping (QSM). When interpreted by a trained physician, STAGE-processed images may provide information that is useful in determining diagnosis for stroke, dementia, Parkinson’s disease, multiple sclerosis, tumours and more.

Though STAGE is considered a comprehensive brain-imaging, postprocessing solution, its approval does not extend outside of brain uses and should always be used in combination with at least one other conventional MRI acquisition technique.

The software is currently being utilised in more than 50 hospitals, imaging centres and research facilities around the globe.

September 2021 | Issue 43

26 Market Watch

ASA highlights value of comprehensive, patientcentred primary care after stroke

Clinical News Synchron to launch US COMMAND trial assessing novel brain-computer interface for paralysis

of the company’s pRESET 4×20 and pRESET 5×40 stentrievers were examined against one another.

The results add to existing evidence that longer stentrievers lead to better patient outcomes.

With the use of the longer stentriever, a significant improvement in recanalisation rates was observed, along with improved mortality rates and fewer passes required to full recanalisation.

First pass success was seen in 68.4% of cases with the pRESET 5×40 while the pRESET 4×20 resulted in first pass success in 48.7% of cases.

This led Serna-Candel et al to conclude that “the size of the stent retriever matters in acute M1 occlusions treated with aspiration-assisted thrombectomy”.

The Stentrode motor neuroprosthesis, developed by Synchron, has taken another step towards becoming the world’s first commercially available, endovascular brain-computer interface (BCI) technology after the company’s investigational device exemption (IDE) application received US Food and Drug Administration (FDA) approval.

The COMMAND trial, an early feasibility study of Stentrode, is set to begin later this year at Mount Sinai Hospital in New York, USA. The study—which plans to enrol a total of six patients—will assess the safety and efficacy of the device in patients with severe paralysis. Outcomes will include the use of brain data to control digital BlueWind Medical enrols devices and achieve improvements in 100th patient in OASIS study functional independence. of Renova iStim system The Stentrode device is delivered BlueWind Medical has announced that into the brain via the jugular vein the 100th patient has been enrolled in in a minimally invasive, two-hour its OASIS study, a clinical pivotal trial procedure. No robotic assistance is designed to test the safety and efficacy required for the procedure, which of the CE-marked Renova iStim system can be performed in widely available in providing tibial neuromodulation angiography suites. The implant is (TNM) to treat overactive bladder. also ‘fully internalised’, with no wires The 100th patient was enrolled at St coming out of the head or body. Patients Mary’s Hospital in London, UK by Alex can begin using the device at home soon Digesu. “I had the privilege of taking after implantation and may wirelessly part in both the pilot and pivotal trials control external devices simply by of the Renova iStim System,” he said. thinking about moving their limbs.

“I find the Renova iStim device easy The system is designed to facilitate to implant for a surgeon and easy to better communication and functional operate for a patient.” independence for patients by enabling OASIS is a prospective, single-arm, daily tasks like texting, emailing, online international multicentre study enrolling commerce and accessing female patients suffering from telemedicine. urinary incontinence.

Synchron is also The study is designed evaluating the to test the safety of device in the the device, as well ongoing SWITCH as the ability of clinical trial, TNM therapy which began to reduce and enrolling patients even eliminate in 2019 at the incontinence Royal Melbourne episodes. At the Hospital in conclusion of the Melbourne, study, BlueWind Australia. Four intends to submit the patients have received device for US Food and the Stentrode implant in the Drug Administration trial, with data from the first pRESET stentriever (FDA) clearance. two patients being published According to Digesu, in the Journal of NeuroInterventional several advantages—including the fact Surgery (JNIS) in October 2020. it is batteryless, leadless, miniature, and utilises closed-loop stimulation—make Phenox highlights benefits the Renova iStim system an “interesting of longer stentriever device option” for patients with overactive with new study results bladder symptoms who do not respond Following its acceptance into Frontiers to, or cannot tolerate, conventional in Neurology, phenox has announced the medical therapy. Results from a previous results of a paper exploring the benefit pilot clinical study show that more than of choosing a longer stentriever for 70% of patients receiving the treatment mechanical thrombectomy procedures. were responders, as measured by In a paper authored by Carmen Serna- composite overactive bladder symptoms, Candel (Klinikum Stuttgart, Stuttgart, with 28% of patients becoming Germany) and colleagues, the outcomes ‘fully dry’.

In a new scientific statement entitled “Primary care of adult patients after stroke”, the American Stroke Association (ASA)—a division of the American Heart Association (AHA)— has provided a roadmap for holistic, goal-directed and patient-centred primary care in the system for adult patients with stroke. The statement is published in the journal Stroke.

“In this statement, we affirm in a new way the role of the primary care professional in caring for people with stroke,” said Walter N Kernan (Yale University School of Medicine, New Haven, USA), chair of the Statement Writing Group. “The core functions of primary care as a speciality include diagnosis and management of acute symptoms, chronic disease management, and disease prevention. Primary care professionals can ensure consistent and comprehensive care for the full needs of patients, including coordinating any additional care or services patients may need from community services providers, or from subspeciality healthcare providers.”

The recent ASA statement summarises the available literature on primary stroke care, and outlines the need for comprehensive post-stroke management that includes engaging caregivers and family members to support the patient. It also alludes to the fact that screening at the first appointment—and all subsequent appointments—should include assessing new or chronic risks for recurrent stroke, such as high blood pressure, high cholesterol, diabetes, atrial fibrillation, and blockage in the carotid or other arteries.

The statement adds that additional screening is important for complications including anxiety or depression, cognitive impairment, bone fracture and fall risk, osteoporosis, pressure

ulcers and post-stroke seizures as well, and that specialist referrals should be recommended for any of these complications as appropriate.

Allegheny Health Network initiates clinical trial exploring use of DBS to treat obesity

A team of physicians at Allegheny Health Network (AHN) has received US Food and Drug Administration (FDA) approval to begin the second phase of a clinical trial exploring the efficacy of deep brain stimulation (DBS) in the management of morbid obesity.

The study will enrol six male and female patients aged 22 to 65 years, who have a body mass index (BMI) of higher than 50, and are at significant risk of morbidity and mortality due to obesity.

These patients will also have undergone gastrointestinal bypass surgery without achieving sustainable results. The broad goals of the study will be to measure the safety and efficacy of DBS in increasing an individual’s metabolic rate.

Leading the study is Donald Whiting (Allegheny General Hospital, Pittsburgh, USA), who also directed a 2013 feasibility trial assessing DBS for obesity in which three patients participated. Each experienced a decreased urge to eat, while none experienced negative side-effects from the treatment.

While the goals of the current trial will be an extension of the first, a new generation of DBS technology featuring major advancements over its predecessor will be used this time around, and lessons learned from the preliminary work will inform the DBS setting being programmed differently to achieve the optimal metabolic rate necessary to boost energy expenditure as well.

Whiting claimed this study may also serve as a framework for future research on other health issues that involve similar neural pathways, such as drug and alcohol addiction.

Industry News Neuro42 closes US$6.5 million Series A financing round

Neuro42 has announced the closing of a US$6.5 million Series A financing round. Zepp Health led the round, and was joined by ShangBay Capital and prominent angel investors Krishna R Bhupal and Philip Dolan.

This financing will enable Neuro42 to advance development of its first-ofits-kind magnetic resonance imaging (MRI) and robotics offerings, allowing physicians to diagnose brain injury in acute settings and treat neurological diseases intraoperatively under live imaging. Neuro42’s technology brings to the market a novel scanner that allows for robotic procedures outside

of the traditional MRI suite, expanding the possibilities of intraoperative image guidance and disease treatment.

To date, the company has raised US$7.8 million—of which US$1.3 million came from an oversubscribed seed round that closed earlier this year.

Cerenovus unveils new data and showcases stroke care innovations at SNIS Cerenovus, part of The Johnson & Johnson Medical Devices Companies, showcased its latest innovations in stroke care at the Society of NeuroInterventional Surgery’s 18th annual meeting (SNIS; July 26–29 2021, Colorado Springs, USA and virtual). The company also announced

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Market Watch 27

several pieces of new clinical data across four scientific poster sessions during the event.

These included findings from a study investigating the multimodal endovascular treatment of widenecked aneurysms, and insights on the impact of COVID-19-related restrictions on clinical trials—both from the STERLING registry—as well as details of a randomised controlled study evaluating the Trufill n-BCA liquid embolic system (Cerenovus) for subdural haematoma, and discussions on the use of the company’s EmboTrap stent retriever for the treatment of acute ischaemic stroke.

In addition, Cerenovus hosted a variety of interactive experiences at its booth, with hands-on demonstrations and education featuring technologies from its ischaemic and haemorrhagic portfolios.

Flow Neuroscience receives Series A funding to advance tDCS depression treatment

Flow Neuroscience has closed a US$9.3 million, oversubscribed Series A funding round led by Khosla Ventures, CSS group through Swiss Health Ventures, and Zühlke Ventures. The round was also joined by Kirin Holdings through the Kirin health innovation fund—led

by Global Brain—SOSV via the HAX programme, and Schox Patent Group.

This investment will be used to advance Flow’s existing depression treatment—a unique transcranial direct current stimulation (tDCS) headset device and behavioural therapy app for depression—making it more patient-specific, and will accelerate the development of non-pharmaceutical, self-managed solutions for other mental health disorders, such as anxiety.

In addition, it will aid the company in its US expansion through clinical trials, Food and Drug Administration (FDA) approval, and US market entry, and enable Flow to strengthen its offering to the European market by servicing patients in their native language.

Michael Chen becomes 26th president of SNIS

Michael Chen, professor of neurology, neurosurgery and radiology at Rush University Medical Center in Chicago, USA, has been named the president of the Society of NeuroInterventional Surgery (SNIS) and will now lead the society’s initiatives to advance excellence in minimally invasive neuroendovascular care.

“We know that tremendous disparities exist in our profession and in how our patients access treatment—addressing

that is going to be a key focus of our work this year,” said Chen.

“Our society, by its nature, is multidisciplinary and also Michael Chen multispeciality, which allows us to not only challenge what we know, but really explore what we do not yet know.

Ultimately, being a part of this society makes us all better physicians and better people.”

Chen has been in practice for more than 14 years at Rush, and focuses on minimally invasive treatments of brain and spinal cord vascular disease. He has authored more than 100 peer-reviewed scientific publications and also serves as a senior editor for the Journal of NeuroInterventional Surgery (JNIS).

William Mack, professor of neurosurgery and vice-chair of academic affairs in the Department of Neurological Surgery at the University of Southern California (USC) Keck Medical Center in Los Angeles, USA, will remain on the SNIS board, and serve as immediate past president. J Mocco (Mount Sinai Hospital, New York, USA) is now president-elect of SNIS, Mahesh Jayaraman (Rhode Island

Hospital, Providence, USA) has been elected vice-president, and Jenny Tsai (Spectrum Health, Grand Rapids, USA) is the society’s inaugural Diversity, Equity and Inclusion chair.

Additional 2021 board members are listed below: Treasurer: Guilherme Dabus, Baptist Cardiac & Vascular Institute, Miami, USA Secretary: Michael T Froehler, Vanderbilt University Medical Center, Nashville, USA Education chair: Peter Kan, University of Texas Medical Branch (UTMB) Health, Galveston, USA Member-at-large—Neuroradiology: Reade A De Leacy, Mount Sinai Hospital Member-at-large—Neurosurgery: Stavropoula I Tjoumakaris, Thomas Jefferson University, Philadelphia, USA Member-at-large—Neurology: Sandra Narayanan, University of Pittsburgh, Pittsburgh, USA Second past president: Richard P Klucznik, The Methodist Hospital, Houston, USA Audit Committee chair: Justin F Fraser, University of Kentucky, Louisville, USA Governance Committee chair: Johanna T Fifi, Mount Sinai Hospital.

Calendar of events 1–3 September 2021 ESOC (European Stroke Organisation Conference) Virtual Event details correct at time of publication.

Please check www. neuronewsinternational. com/events for updates in the wake of COVID-19.

www.eso-conference.org

14–16 September 2021 LINNC (Live Interventional Neuroradiology, Neurology & Neurosurgery Course) Paris Paris, France and virtual

8–10 September 2021 ESMINT (European Society of Minimally Invasive Neurological Therapy) Congress Nice, France

15–16 September 2021 European Neuro Convention Birmingham, UK

www.esmint.eu/esmint-congress

www.linnc.com/Course-information/ LINNC-Paris-2021

www.neuroconvention.com

26–28 September 2021 World AVM (ArterioVenous Malformations) Congress New York City, USA

28–29 October 2021 WSC (World Stroke Congress) Virtual https://worldstrokecongress.org

17–20 November 2021 SVIN (Society of Vascular and Interventional Neurology) Annual Meeting Phoenix, USA www.svin.org

13–16 December 2021 BRAIN (Barts Research and Advanced Interventional Neuroradiology) Conference London, UK https://www.brainconference.co.uk

13–16 January 2022 NANS (North American Neuromodulation Society) Annual Meeting Orlando, USA https://neuromodulation.org/ Meetings/2022AnnualMeeting

www.avm2021.org

international.com

www.neuronews

April 2021

| Issue 41

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