Management Strategies for Asymptomatic Carotid Stenosis: A Systematic Review and Meta-Analysis
What is the benefit of revascularization when compared with medical therapy for asymptomatic patients with carotid stenosis?
This was a systematic review of the published and unpublished literature. The review included MEDLINE, Cochrane Central Register of Controlled Trials, US Food and Drug Administration documents, and a review of references through December 31, 2012, from these documents. Both randomized controlled trials (RCTs) and nonrandomized studies were included.
Forty-seven studies in 56 publications were eligible. The RCTs comparing the two approaches for revascularization—carotid endarterectomy and carotid artery stenting—were clinically heterogeneous. None of the trials showed definitive support for either approach over the other, nor did any of the trials demonstrate clear superiority over medical therapy. Of note: no trial has compared carotid artery stenting with medical therapy. The summary incidence of ipsilateral stroke across 26 cohorts receiving medical therapy alone was 1.68% per year, although this seems to be lower in more contemporary studies.
The authors concluded: “Future RCTs of asymptomatic carotid artery stenosis should explore whether revascularization interventions provide benefit to patients treated by best-available medical therapy.” They also emphasize “the uncertainty that remains in this area,” and that “event rates in patients treated with medical therapy have decreased over time.”
This review by Raman et al., focuses on a specific question: What is the benefit of revascularization when compared with medical therapy for asymptomatic patients with carotid stenosis? This is an important question given the high prevalence of patients with carotid stenosis who are asymptomatic. The following are five key points to remember from this article:
1. Current RCT evidence supporting carotid endarterectomy and carotid artery stenting for asymptomatic patients is severely limited when compared with medical therapy, reflecting some discordance across guidelines for recommendations in these patients.
2. Part of the challenge for justifying revascularization is the overall low rates of ipsilateral stroke noted in medical therapy arms of studies: 1.68% per year for all studies and 1.18% for more contemporary studies.
3. Some additional methods (e.g., plaque ulceration) may define a higher-risk group of patients who may benefit from revascularization, but robust studies on the incorporation of these findings into clinical practice are lacking.
4. Operators performing revascularization in asymptomatic patients must demonstrate low rates of periprocedural complications to justify the long-term benefit with either carotid endarterectomy or carotid stenting.
5. Somewhat surprisingly, it has only been recently that medical therapy in these studies has included antihypertensive and lipid-lowering therapy (in addition to antiplatelet therapy). Ongoing trials are being performed in asymptomatic patients, but many continue to be focused on comparisons between the two approaches for revascularization, rather than with medical therapy.
Keywords: Stroke, United States Food and Drug Administration, Endarterectomy, Carotid, Carotid Arteries, Carotid Stenosis, Stents, MEDLINE
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