“Excellent” primary success of limb ischaemia thrombectomy study shared as podium first

The acute limb ischaemia programme at 2023 Charing Cross (CX) International Symposium (25–27 April, London, UK) featured a first-to-podium presentation by Sean Lyden (Cleveland Clinic, Cleveland, USA)—primary endpoint results of the STRIDE trial. Designed to report 30-day safety and performance of the Indigo aspiration system (Penumbra), the trial is an international, multicentre, prospective, single-arm, observational study of patients with lower extremity acute limb ischaemia. Lyden informed the audience that the study had successfully met its primary endpoint of target limb salvage at 30 days post-procedure.

STRIDE’s patient cohort numbered 119 patients (of 285 initially screened), across 16 sites in the USA and the European Union. The mean age of patients was 66.3±13.27, and 55/119 were women, the presenter detailed. The highest rates of other medical conditions among patients were hypertension (n=103) and hyperlipidaemia (n=100).

Lyden shared that the inclusion criteria stipulated that patients participating in the trial must have had occlusion of one or more lower limb arteries below the inguinal ligament for up to 14 days, and have a Rutherford category score of I, IIa or IIb. Of the enrolled patients, 10.9% were ‘viable’, with a Rutherford category I score, 54.6% ‘threatened marginally’ classified as IIa, and 34.5% ‘threatened immediately’ with a IIb score.

Patients with a target vessel size of less than 2mm, amputation in the ipsilateral limb, or with target thrombus in a saphenous vein bypass graft were excluded from the trial, the speaker added.

Eight patients of the 119 enrolled exited the study before the 30-day follow-up point—five died, one was lost to follow-up, and two patients withdrew, Lyden supplemented. A further two patients missed 30-day follow-up.

In terms of the primary endpoint, target limb salvage at 30 days was achieved in 109 patients, according to the presenter. Multiple secondary endpoints were also measured— efficacy endpoints comprised patency at 30 days, and modified Society for Vascular Surgery (SVS) runoff score immediately postprocedure versus baseline. Lyden elaborated that the results for these measures were 90.3% success and an improvement of SVS runoff score of 6.3±5.49, respectively. Regarding safety-related secondary endpoints, device-related serious adverse events numbered one and major periprocedural bleeding was reported in five patients.

Furthermore, the speaker said, the median time taken to carry out thrombus aspiration with the Indigo system was 22.0 minutes (interquartile range 12.0–47.0).

Lyden concluded that STRIDE study patients treated frontline with the Indigo aspiration system had “excellent” limb salvage rates, a “low” rate of periprocedural complications, and a “high” technical success rate. “Mechanical aspiration thrombectomy provided a safe and effective alternative therapeutic option for lower extremity acute limb ischaemia patients,” were the presenter’s parting words.

In the discussion following Lyden’s presentation, moderator Gunnar Tepe (RoMed Klinikum, Rosenheim, Germany) asked how often during the STRIDE study it was necessary to perform any additional procedures. The presenter responded that there were a “small proportion of patients” who received postoperative thrombolysis after incomplete mechanical aspiration, the data for which will be included in the paper that principal investigator Thomas Maldonado (New York University Langone Health, New York, USA) is currently working on.

Another question probed what is next for the STRIDE study, with Lyden noting that the first thing the study team are planning to do is “get into the dataset” and look at all the cohorts that were included in terms of type of pathology and the vessels that were treated.

Bioresorbable drug-eluting stents swing CX audience vote following peripheral trial update

Following updates from multiple studies assessing bioresorbable drug-eluting stents, the majority (69%) of CX 2023 audience members in the peripheral arterial and chronic limb-threatening ischaemia (CLTI) session voiced support for these technologies, voting in favour of the statement that ‘bioresorbable wins’.

HOWEVER, QUESTIONS WERE RAISED over the length of time it takes for these devices to be resorbed following implantation. Responding to session anchor Roger Greenhalgh’s (Imperial College London, London, UK) question regarding their strength, and their longevity, panellist Ramon Varcoe (University of New South Wales, Sydney, Australia) said one example of these stents—the Esprit below-the-knee (BTK) scaffold (Abbott)—is only slightly less strong than a metallic stent, but how long they last is “up for debate”.

“There is a school of thought out there that these stents should actually dissolve more quickly,” Varcoe stated, also touching on the fact that the Esprit device takes roughly 18–24 months to be resorbed, despite the fact drug-eluting stent treatments in BTK patients may need no longer than six months to be effective.

Delivering an update on the LIFE-BTK randomised trial—which he feels has become “the new gold standard” in BTK studies—Varcoe said the “excellent” long-term patency and freedom from target-lesion revascularisation (TLR) Esprit achieved in an earlier proof-of-concept study facilitated this larger, multicentre undertaking. He concluded by noting that LIFE-BTK enrolment has now closed, and results are set to be released later this year.

A similarly positive outlook was then delivered by Michel Bosiers (University Hospital Bern, Bern, Switzerland) in his presentation of an update from the MOTIV trial, the results of which showed a 99% rate of technical success in delivery and revascularisation, as well as 88.3% vessel patency after 12 months, in BTK cases. In this prospective, multicentre study assessing the sirolimus-eluting Motiv bioresorbable scaffold (Reva Medical), Bosier emphasised “excellent” tracking and visibility during implantation; low adverse event rates; and a single, clinically-driven TLR across the entire patient cohort.

During the same session, EFEMORAL I trial results indicating the ability of the Efemoral vascular scaffold system (EVSS; Efemoral Medical) to target a “significant” unmet need in peripheral vascular intervention for femoropopliteal disease were presented by Andrew Holden (Auckland City Hospital, Auckland, New Zealand). In his update on the trial, Holden disclosed encouraging initial results in short lesions.

Despite “no safe and effective formulation of any [bioresorbable] vascular scaffold” being realised to date in the peripheral vascular bed, according to Holden, development of the EVSS specifically for use in this area has provided high radial strength, “unencumbered” movement of the femoropopliteal axis and prolonged sirolimus elution.

With a look to the future, Varcoe acknowledged the relevance of translating these promising findings from proof-of-concept to “real-world disease”, before Holden drew the session to a close by stating that inflammation presents an additional challenge moving forward—quipping that “neointimal hyperplasia has been their Achilles’ heel” in the past.