Introduction: Increasing stenosis has been questioned as a factor increasing risk of carotid endarterectomy (CEA) or carotid stenting (CAS) in patients with severe asymptomatic carotid stenosis.
Hypothesis: Greater severity of carotid stenosis is associated with higher rates of periprocedural stroke and death following revascularization for asymptomatic patients.
Methods: Asymptomatic patients with carotid stenosis ≥ 70% by ultrasound or ≥ 60% by angiogram were eligible for the Carotid Revascularization Endarterectomy vs Stenting Trial (CREST). Patients who had a catheter-angiogram were divided into tertiles based on the degree of stenosis. Outcomes were the occurrence of any stroke or death at 30 days. Proportional hazards models adjusting for age and treatment were used to assess risk of 30 day stroke or death by tertile of stenosis.
Results: Among 1181 asymptomatic patients, qualifying angiograms were done for 662 patients who had assigned procedure performed within 30 days of randomization. Median % stenosis was 62.6, 73.4, and 83.0 for the tertiles that otherwise differed only for female sex (40% female in tertile 1, 36% in tertile 2, 29% in tertile 3, p=0.01). The 30-day stroke and death rates did not differ significantly by severity of stenosis (Table), but the number of stroke and deaths was only 14 across the tertiles (Table). Similarly meaningful comparison of CEA vs CAS was not possible.
Conclusion: This is the largest contemporary study of carotid angiograms performed in patients with severe asymptomatic carotid stenosis. No relationship was detected between severity of stenosis and 30-day stroke and death. The safety of CEA and CAS in asymptomatic patients limits detection of other factors that may increase risk because so few events complicate these procedures.