Background:
The SAMMPRIS trial showed that aggressive medical therapy was more effective than stenting for preventing stroke in high-risk patients with symptomatic intracranial stenosis. However, 15% of patients in the medical group still had a primary endpoint (any stroke or death within 30 days of enrollment or stroke in the territory beyond 30 days) during a median follow-up of 32.7 months. We sought to determine baseline risk factors that were associated with a primary endpoint in the medical arm of SAMMPRIS.
Methods:
Data on 227 patients randomized to the medical group in SAMMPRIS were analyzed. Baseline demographic features, vascular risk factors, qualifying event, brain imaging and angiographic features were analyzed. The hazard ratio and p-value from a Cox proportional hazard regression model relating time until a primary endpoint to each factor were calculated.
Results:
Female gender, diabetes, stroke as the qualifying event (especially non-penetrator stroke), old infarct in the territory of the stenotic artery, and > 80% stenosis were associated (p < 0.10) with a higher risk of the primary endpoint on univariate analysis (see accompanying table) (multivariate analysis will be available by the time of ISC). Variables not associated with a higher risk of a primary endpoint in the medical arm included: age, race, antithrombotic therapy at the time of a qualifying event, time from qualifying event to enrollment (< 7 days vs. > 7 days), and location of stenosis.
Conclusions:
Several features were associated with an increased risk of the primary endpoint in the medical group in SAMMPRIS. On univariate analysis, the most important risk factors were an old infarct in the territory of the stenotic artery and stroke (especially non-penetrator stroke) as the qualifying event. These features will be useful for identifying particularly high-risk patients who should be targeted for future clinical trials testing alternative therapies to aggressive medical management.
Carotid Intervention for High Grade Asymptomatic Carotid Stenosis does not Confer Stroke Prevention over Best Medical Therapy