Stroke Patients with Carotid Webs Are at High Risk for Recurrent Stroke
By Mark Moran
July 22, 2021
Article In Brief
Patients with carotid webs (CWs) have an increased risk of recurrent stroke compared to those without carotid web. Clinicians should be on the lookout for CWs in young stroke patients, treat them with an awareness of the high risk for recurrence, and actively follow them, experts say.
Carotid webs (CW) are an underrecognized condition in stroke patients that appear to be a significant risk factor for recurrent stroke, according to a report published May 10 online in JAMA Neurology.
The CWs appear as a thin ridge of tissue comprised of intimal fibrous proliferation arising from the posterior wall of the internal carotid artery; they are presumed to cause stroke by disrupting flow and allowing blood to pool behind the web and then clot, with subsequent downstream embolization.
The JAMA Neurology study found that one in six stroke patients (17 percent) with CW had a recurrent stroke within two years, suggesting that medical management alone—typically antiplatelet therapy—is ineffective or insufficient.
Co-author Jonathan Coutinho, MD, a neurologist at Amsterdam University Medical Centers, said clinicians should be on the lookout for CW in patients with cryptogenic stroke. “It's uncommon but not rare, and clinicians often don't look for carotid webs,” he told Neurology Today. “If you know what to look for, it's not a difficult diagnosis. And clinicians need to follow-up actively. We tend to discharge patients after stroke but based on our data, the recurrent risk is so high it calls for active monitoring.”
A 2018 systematic review in the journal Stroke reported an ischemic stroke recurrence rate of 56 percent in patients with CW receiving medical management. But that data was drawn from case reports and uncontrolled, retrospective, single-center studies.
The new report draws on a more unbiased sample from a large Dutch national registry.
Dr. Coutinho said antiplatelet therapy is the standard regimen for patients with stroke of an unknown origin but appears to be ineffective in these patients who had CWs; anticoagulant therapy or stenting may be necessary.
“I can't recommend what is the best treatment but based on our data, antiplatelet therapy is not the way to go,” he said.
Study Methods, Findings
Dr. Coutinho and colleagues compared cohorts using data from the MR CLEAN trial (December 2010-March 2014) and the MR CLEAN Registry (March 2014-November 2017). The MR CLEAN trial was a randomized clinical trial conducted at 16 centers in the Netherlands in which adult patients with ischemic stroke due to an anterior circulation large vessel occlusion (LVO) were randomized to endovascular treatment (EVT) or no EVT. The MR CLEAN Registry was a nationwide observational cohort study in which data were collected from consecutive patients with LVO stroke treated with EVT in the Netherlands.
All CTA images from the MR CLEAN trial and registry were reassessed by an experienced neuroradiologist to determine whether patients had a CW ipsilateral to the index stroke. They defined CW on CTA as a thin linear filling defect arising from the posterior wall of the proximal internal carotid bulb, with a typically smooth border and without atherosclerosis.
Thirty of 3,439 patients (0.9 percent) who had CTAs were determined to have a CW. None of the patients with a CW had a stenosis greater than 50 percent according to North American Symptomatic Carotid Endarterectomy Trial criteria due to their CW. (Fifty percent stenosis is generally the cutoff requiring intervention in atherosclerotic carotid disease).
Twenty-eight of 30 patients (93 percent) received medical management to prevent recurrent stroke after the index stroke. Of those, 23 were prescribed antiplatelet agents (15 single and eight double) and five anticoagulants. None of the patients with CW underwent carotid stenting.
During the two years after the index stroke, five of 30 patients (17 percent) with an ipsilateral CW had a recurrent stroke, compared with five of 168 patients (3 percent) without a CW.
Experts who reviewed the study for Neurology Today agreed that despite the small numbers—which render a precise determination of risk difficult—the study makes clear that the risk is in any case unacceptably high.
Karen Furie, MD, MPH, chair of neurology at Rhode Island Hospital, The Miriam Hospital and Bradley Hospital, and chair of the department of neurology at The Warren Alpert Medical School of Brown University, called the study “a really innovative use of their data set that supports previous literature on carotid web and suggests that webs significantly raise the risk of stroke recurrence.”
Christopher Streib, MD, MS, cerebrovascular director at the University of Minnesota Health-Fairview and a co-author of the 2018 report in Stroke, said the JAMA Neurology paper breaks new ground. “The major strength of this study, in comparison to prior publications such as ours, is that the recurrent stroke risk was determined in a cohort of patients with symptomatic carotid web that were identified and followed prospectively,” he told Neurology Today. “Nearly all the patients in this cohort completed their follow-up, which helped avoid potential selection biases present in prior studies.”
“The primary weakness of this study is the small sample size which makes it hard to draw definitive conclusions. Two of the five patients with symptomatic CW who suffered recurrent stroke were in their 90s and potentially had alternative causes of stroke. However, the conclusion of the study, that medical treatment alone may not be adequate to prevent recurrent stroke in patients with symptomatic CW reinforces the findings of prior research on this topic.”
Dr. Streib added: “A compelling finding from this study is that in all patients with symptomatic CW and recurrent stroke, the recurrent stroke occurred in the same vascular territory as the CW. This means that the stroke was ‘downstream’ from the carotid web and that the carotid web is likely to have played a role in the process.”
Carolyn Cronin, MD, PhD, director of the vascular neurology fellowship program at the University of Maryland School of Medicine, agreed and emphasized that CWs are likely underdiagnosed. “Carotid webs are best seen on high-resolution CT angiogram studies, which have only become widely available in the past decade, so the knowledge base is relatively limited,” she said. “It is not known how they form or how prevalent they are. They appear to cause stroke by disrupting flow and allowing blood to pool behind the web and then clot, with subsequent downstream embolization.”
The experts interviewed by Neurology Today emphasized the need for research going forward to determine the best way to treat webs with an eye toward the prevention of stroke recurrence. In the meantime, they said clinicians should be on the lookout for CWs in young stroke patients, treat them with an awareness of the high risk for recurrence, and actively follow them.
“The take-home message for the stroke and broader neurology community is to be keenly aware of the carotid web as an important underlying stroke etiology,” said Dr. Streib. “Carotid web rarely causes hemodynamically significant stenosis and is easily missed on routine imaging without dedicated attention to this disease. While it is not established that all symptomatic carotid webs require carotid stenting instead of medical management, both medical and surgical treatment options should be considered by treating providers and patients.”
Dr. Cronin agreed. “Evaluation for carotid webs should be part of the stroke work-up for patients in whom an etiology is not found in cryptogenic stroke or unilateral embolic strokes of undetermined source (ESUS). Intervention with CEA or stenting appears to be effective and should be strongly considered.”
“It's not uncommon that vascular neurologists will conclude that a stroke is cryptogenic, and we typically think of the heart as the source of those,” Dr. Furie concluded. “This study is a reminder that vascular lesions which are not necessarily flow-limiting may contribute to some of the cases, and the finding of a carotid web should not be dismissed as purely incidental.”
Dr. Coutinho reported grants from Boehringer Ingelheim (All fees paid to institute and used to fund research), grants from Bayer (All fees were paid to the institute and used to fund research), and grants from Medtronic (all fees were paid to the institute and used to fund research) outside the submitted work. Drs. Furie, Streib, and Cronin had no disclosures.