Association Between Ipsilateral Stroke and Nonstenotic (<50%) Carotid Disease: Secondary Analysis From the AcT Trial

Abstract

BACKGROUND: Symptomatic nonstenotic (<50% stenosis) carotid disease in the presence of high-risk plaque features is a potential cause of ischemic stroke. We assessed stroke risk associated with symptomatic nonstenotic carotid disease. METHODS: This cross-sectional secondary analysis of the AcT (Alteplase Compared to Tenecteplase) randomized controlled trial evaluated baseline computed tomography angiograms for degree of internal carotid artery stenosis, plaque features and the presence of intraluminal thrombi, webs, dissection, and rim sign. Stroke location was evaluated on 24-hour follow-up imaging. At a carotid level, mixed-effects logistic regression models adjusted for age and sex, with patient identity as a random effect, examined associations between “concordant stroke” (ipsilateral acute stroke in the internal carotid artery territory) and symptomatic nonstenotic carotid disease. RESULTS: Of 1577 patients enrolled, 1407 (89.2%) with interpretable imaging were included: 329 (23.4%) had no carotid disease, 869 (61.8%) had nonstenotic carotid disease, and 209 (14.9%) had stenotic (≥50%) carotid disease in either the left or right internal carotid artery. Median age was 73 years (interquartile range, 63–83), with 48% female patients. Among 2519 (89.5%) internal carotid arteries with nonstenotic disease, 689 (27.4%) concordant strokes were identified. Intraluminal thrombi, carotid webs, carotid dissections, and carotid rim sign were significantly associated with concordant stroke (adjusted odds ratio, 8.11 [95% CI, 1.60–41.08]; adjusted odds ratio, 3.58 [95% CI, 1.53–8.35]; adjusted odds ratio, 6.77 [95% CI, 1.72–26.75]; and adjusted odds ratio, 3.17 [95% CI, 1.39–7.23], respectively). Results remained unchanged after excluding patients with atrial fibrillation and lacunar infarctions. CONCLUSIONS: Features other than the degree of stenosis should be considered when evaluating patients with carotid disease.