Abstract Number ‐ 239: Subcortical Infarcts in Patients with Nonstenotic Cervical Atherosclerotic Disease

Abstract

Introduction Prior studies have elucidated a relationship between nonstenotic plaque in patients with cryptogenic embolic (cortical) infarcts, however it is unclear if nonstenotic carotid plaque is relevant in subcortical infarct patterns. Methods A nested cohort of consecutive patients with anterior, unilateral, subcortical infarcts without an identifiable embolic source were identified from a prospective stroke registry (September 2019 ‐ June 2021). Patients with extracranial stenosis >50% were excluded. Patients with computed tomography angiography were included and comparisons made according to infarct pattern being lacunar (single lesion < 1.5cm on computed tomography [CT] or < 2.0cm on diffusion weighted imaging [DWI]) versus cryptogenic (≥ 1.5cm on CT or ≥ 2.0cm on DWI, or scattered subcortical lesions). Prevalence estimates for cervical internal carotid artery (ICA) plaque presence were estimated with 95% confidence intervals (CI), and differences in plaque thickness and features were compared between sides. Results Of the 1684 who were screened, 141 met inclusion criteria (n = 80 due to small vessel disease, n = 61 cryptogenic). The median age was 66y (interquartile range, IQR 58–73) and National Institutes of Health Stroke Scale score was 3 (IQR 1–5). There was a higher probability of finding excess plaque ipsilateral to the stroke (41.1%, 95%CI 33.3‐49.3%) than finding excess contralateral plaque (29.1%, 95%CI 22.2‐37.1%; p = 0.03), but this was driven by patients with cryptogenic infarcts (excess ipsilateral vs. contralateral plaque frequency of 49.2% vs. 14.8%, p< 0.001) and not lacunar disease (35.0% vs. 40.0%, p = 0.51). Conclusions The probability of finding ipsilateral, nonstenotic carotid plaque in patients with subcortical cryptogenic strokes exceeds the probability of contralateral plaque and is driven by larger subcortical infarcts, classically defined as being cryptogenic. Approximately 1 in 3 unilateral anterior subcortical infarcts may be due to nonstenotic ICA plaque.