Abstract WP155: Relationship Between Nonstenotic Plaque, Left Atrial Enlargement, And Age In Patients With Embolic Stroke Of Undetermined Source: A Multi-center Observational Cohort Study

Abstract

Background: Nonstenotic internal carotid artery (ICA) plaque as a mechanism of embolic stroke of undetermined source (ESUS) is controversial. Studies show an inverse relationship between cardioembolic stroke risk and nonstenotic plaque in ESUS patients. We explored this relationship using left atrial enlargement (LAE) as a marker of cardioembolic stroke predisposition. Methods: A retrospective multicenter cohort of consecutive patients with unilateral, anterior circulation ESUS was queried. ESUS diagnosis was based on an embolic stroke pattern without an identifiable source on imaging and ≥24hrs of telemetry. Descriptive statistics were used to differentiate clinical, laboratory, and imaging predictors of sex adjusted LAE. Results: Of the 4155 patients screened, 273 (7%) met the inclusion criteria. Compared to patients without LAE, those with LAE were older (68y vs 62y, p<0.01), and had more frequent hypertension (83.7% vs 66.9%, p<0.01) and coronary artery disease (22.8% vs 11.3%, p=0.02). All had greater ipsilateral than contralateral ICA plaque (median 1.9cm [IQR 0-3] vs 1.5cm [IQR 0-2.6], p<0.01) without any difference in stenosis (median 0% [IQR 0-0] vs. 0% [IQR 0-0], p=0.19). Patients under 70 had greater plaque ipsilateral versus contralateral than patients 70 or older (mean difference 0.42cm [±1.24] vs 0.08cm [±1.54], p=0.047), and were less likely to have any LAE (28.6% vs 42.9%, p=0.02) or moderate-to-severe LAE (6.3% vs 15.3%, p=0.02). The probability of finding more ipsilateral than contralateral plaque in ESUS patients exceeded chance (50%) for patients under 70 (Figure). Discussion: Clinically relevant ipsilateral ICA plaque was more frequent in this ESUS cohort, regardless of LAE. When stratified by age, younger patients had greater ipsilateral ICA plaque burden and less LAE. While nonstenotic plaque and LAE frequently co-exist, younger ESUS patients were at greater risk of nonstenotic plaque than the elderly, who were at greater risk of LAE.