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Vascular Specialist | Thursday 16 June 2022
CAROTID SURVEILLANCE Study of post-CEA surveillance prompts protocol discussion THE RESULTS OF AN ANALYSIS OF NEARLY 2,000 carotid endarterectomies (CEAs) “challenge the notion” that patients benefit significantly from the current postoperative surveillance guidelines, and suggest that these may be contributing to “oversurveillance”—an issue that should be addressed in future protocols for patient management post-CEA. These were among the talking points to emerge from a presentation delivered by Colleen P. Flanagan, MD, an integrated vascular surgery resident from the University of California San Francisco, who presented the results of a retrospective study looking at the long-term results of post-CEA surveillance within an integrated regional healthcare system, delivered during Plenary Session 2 Wednesday morning. Flanagan and colleagues, along with senior author Robert Chang, MD, assistant chair of vascular surgery at San Francisco’s Kaiser Permanente Foundation Hospital, the healthcare system in question—sought to evaluate the long-term utility of surveillance after CEA in preventing stroke and identifying restenosis. Current Society for Vascular Surgery (SVS) guidelines recommend a surveillance regimen consisting of up to five duplex ultrasound assessments in the first two years after a CEA, with annual scans thereafter, Flanagan noted in her presentation. Conversely, current recommendations from the European Society for Vascular Surgery (ESVS) favour a less rigorous approach, advocating carotid artery surveillance if there are signs of cerebral malperfusion during carotid clamping. The study included patients who underwent CEA for severe (70–99%) carotid artery stenosis between 2008 and 2012, who were then followed up until 2019. Flanagan
described Kaiser Permanente as a “large, integrated regional healthcare system”, and detailed that patients who had undergone ipsilateral intervention previously, or who died within 30 days of their operation were excluded. The primary outcomes, Flanagan told delegates, were ipsilateral severe restenosis or ocColleen p clusion, and ipsilateral stroke. She Flanagan also noted that a competing risks analysis was used to quantify freedom from the primary outcomes. In terms of results, 1,923 carotid arteries in 1,816 patients were treated with CEA during the study period, Flanagan noted, of which 831 (43.2%) were for symptomatic indication. Mean follow-up time was 6.6 years (SD=3.3 years). A median of three surveillance studies were completed across the patient population during the study period, lower than the five recommended under current SVS protocols, and 13.5% of patients received no postoperative surveillance at all, Flanagan reported. The presenter noted that 1.4% of arteries underwent reintervention during the study period, and of the 71 ipsilateral postoperative strokes that occurred, only three occurred in the setting of a known severe restenosis. The five-year risk of severe restenosis, occlusion and ipsilateral stroke seen in the study were 6%, 9.9% and 2.7% respectively, Flanagan noted. “The risk of severe restenosis and occlusion were especially low, if [a] patient’s first postoperative imaging study was normal, whereas ipsilateral stroke decreased only slightly,” she stated. “Despite less frequent surveillance compared to SVS guidelines, our observed ipsilateral stroke rate was actually lower than those previously reported in clinical trials,” Flanagan went on to remark. “Risk of restenosis was also particularly low, especially if the patients received a normal postoperative imaging study. “Our data suggest a reconsideration of carotid surveil-
lance protocols are warranted after CEA. Following a normal first postoperative imaging study, additional scans are likely not necessary.” The study team is conducting further analysis in order to identify any sub-populations that may require more frequent surveillance and attempting to understand the concurrent contralateral disease rate within this population, the presenter reported. The study’s findings elicited a strong response from Ali AbuRahma, MD, speaking from the floor, who commented that he has been “preaching on the same issue” for over a decade. AbuRahma said that he had been involved in collecting randomised trial data over 10 years ago which he said suggest that: “If you do surgery right from the first time… the value of having postoperative ultrasound frequently, to me, was absolutely unacceptable.” A need for additional and unnecessary surveillance may place an increased financial burden on overstretched healthcare systems, he said. “I am trying to keep that in mind when we put the guidelines together this time for carotid management,” AbuRahma commented further. “I want the audience to be careful and perhaps we need to revisit the same issue.” Expanding, Flanagan told Vascular Specialist@VAM that “oversurveillance is a problem primarily because it constrains important resources that other patients need.” The day-to-day implications of this overuse of finite hospital resources can be delays in access imaging, which many patients require as part of screening, surveillance or diagnosis of their conditions, the research team elaborated.
“Oversurveillance is a problem primarily because it constrains important resources that other patients need” COLLEEN P. FLANAGAN
CAROTID REVASCULARIZATION
LOW RATE OF NEW WHITE LESIONS DETECTED AFTER TCAR USING DIFFUSION-WEIGHTED MRI By Will Date NEW WHITE LESIONS ARE NOT A common occurrence in patients who have undergone transcarotid artery revascularization (TCAR), a study in which patients were assessed post-procedurally using diffusion-weighted magnetic resonance imaging (DW-MRI), has found. This was the finding delivered by Raghu Motaganahalli, MD, who presented data from a multicenter, single-arm, open-label study evaluating the incidence and volume of new white lesions occurring within 30 days after TCAR. Motaganahalli told attendees of Plenary 2, Wednesday morning, that the outcomes of the analysis should serve as the benchmark for future compar-
isons evaluating carotid revascularization strategies on cerebral new white lesions. Diffusion-weighted imaging has high sensitivity and specificity for the early detection of ischemic lesions, Motaganahalli detailed in his presentation, noting that on DW-MRI, early ischemic lesions appear as new white lesions. Data from previous studies suggest that there is around a 17% chance of patients developing new white lesions following a TCAR procedure, Motaganahalli said, adding that the study presented at VAM 22 is the first in the U.S. to evaluate
the occurrence of new white lesions using DW-MRI. Fifty five patients were enrolled across five centers from the U.S., as well as centers in Madrid, Spain, and Munich, Germany. Each patient underwent three MRI scans, one within the 72 hours preceding the TCAR procedure, another before their discharge from hospital, and a third at 30day follow-up. Relating to the study’s primary endpoint, detection of new white lesions from the DW-MRI scan, Motaganahalli communicated that new white lesions were seen in 14.5% of patients prior to the TCAR procedure, with a mean volume of 0.11cc. New white lesions were then seen in 21.8% of the study population in scans taking place between 12–60 hours post-procedure, with a mean volume of 0.03cc. Predominantly these were distributed in the territory of the middle cerebral artery, Motaganahalli said. “When you
look at the 30-day follow-up, the majority of these lesions disappear,” Motaganahalli then detailed, adding that lesions persisted in only 5.8% of the patients assessed at this timepoint. The mean volume of the lesions at this point was 0.21cc, which were again predominantly located in the territory of the middle cerebral artery. No incidences of stroke or neurological death, the study’s secondary endpoints, were observed. “Patients who underwent TCAR and DW-MRI post-procedurally had a low incidence of new white lesions,” the presenter told attendees of the Plenary 2 session. Of these, he added, the majority were in the ipsilateral hemisphere, and located in the middle cerebral artery territory and distribution. “These lesions are very small, and those procedures [when] followed-up the majority of them are resolved,” Motaganahalli added. The results of the study should serve as a benchmark, and point to the detection of new white lesions as a surrogate marker for future carotid revascularization clinical trials, he concluded.
