Ravinder-Jeet Singh, MBBS, DM
A carotid web is a fibro-intimal membrane which projects into the lumen of the internal carotid artery immediately after the bifurcation. Histologically an intimal variant of fibromuscular dysplasia, it has characteristic angiographic appearance seen as septum on axial imaging (CTA, MRA or carotid ultrasound) and as a shelf on sagittal reformats of CTA/MRA or lateral projections of catheter angiogram. Although initially considered to be an uncommon cause of stroke, its prevalence was reported to be about 1.2% among unselected consecutive stroke/TIA patients in one CTA-based study to as high as 37% in another study, which included young Afro-Caribbean patients with stroke of cryptogenic etiology in the carotid distribution. Natural history and treatment options for the carotid web are poorly defined.
In the present review, the authors performed a systematic search of the literature on patients with carotid web and acute ischemic stroke to define clinical characteristics, natural history, treatment options and outcome of these individuals.
The search revealed 37 studies describing 158 patients published between 1968 and December 2017. Patients were predominantly healthy (57% no risk factors) young adult (median age 46 years) females (68%) with a symptomatic carotid web (76%). Among incidentally detected carotid web, there were no reported TIA/stroke, and most subjects were prescribed antiplatelet therapy. In contrast, patients with symptomatic web had high stroke recurrence, 56% at a median 12 months follow-up, while on medical therapy, which largely consisted of antiplatelet therapy. Nearly three-quarters of the patients (either after the first or recurrent event) were treated with carotid intervention, stenting or CEA, with no recurrence of stroke at a median follow-up of 10.7 months for CAS and 14 months for CEA. All patients tolerated the procedure well with no periprocedural complications. The authors concluded that ischemic stroke associated with carotid web occurs in younger patients without conventional stroke risk factors, and carotid intervention is safe and more effective compared to medical therapy to prevent stroke recurrences in these patients.
As acknowledged by the authors, there is a high likelihood of publication and reporting bias. Moreover, included studies were very heterogeneous in the patient population. This heterogeneity occurred owing to lack of defined criteria for the carotid web. Thus, some reports might have had included patients with carotid plaques, especially those studies which reported elderly patients with the web. In addition, there were very few patients on dual antiplatelet therapy or oral anticoagulation to provide any firm evidence regarding their efficacy and safety. Finally, data on carotid intervention is limited to short and intermediate-term. Given the young age of these patients, long-term data are needed to establish true efficacy and safety of these procedures.
Although the study attempts to improve understanding about the carotid web, knowledge gaps continue to exist on natural history and treatment options. Future studies using a clear and more uniform definition of the carotid web should compare different medical treatment options and also medical therapy vs. carotid interventions in a larger sample. Data on asymptomatic web is very limited, and no follow-up studies are available to inform the biological behavior of these webs long-term.