Abstract TP199: Incidence, Characteristics and Outcomes in Patients With Embolic Stroke of Undetermined Source: A Population-based Study

Abstract

Introduction: Embolic stroke of undetermined source (ESUS) represents a subgroup of cryptogenic ischemic stroke (CS) distinguished by high probability of an underlying embolic mechanism. There are scarce population-based data regarding the incidence, characteristics and outcomes of ESUS. Methods: Consecutive patients included with first-ever ischemic stroke of undetermined cause in the previously published population-based Evros Stroke Registry were further subdivided into ESUS and non-ESUS CS. Crude and adjusted [according to the European Standard Population (ESP), WHO and Segi population] incidence rates (IR) for ESUS and non-ESUS CS were calculated. Baseline characteristics, admission stroke severity (assessed using NIHSS-score), stroke recurrence and functional outcomes [determined by modified Rankin Scale (mRS) scores], were recorded during the 1-year follow-up period. Results: We identified 21 and 242 cases with ESUS (8% of CS) and non-ESUS CS. The crude and ESP-adjusted IR for ESUS were 17.5 (95%CI: 10-25) and 16.6 (95%CI: 10-24) per 100,000 person-years. Patients with ESUS were younger [median age 68 years (IQR:61-75) vs. 79 years (IQR:73-83); p<0.001] and had lower median admission NIHSS-scores [4 points (IQR:2-8) vs. 8 points (IQR:5-16); p<0.001]. Functional outcomes were more favorable in ESUS at 28 [median mRS-score: 2 (IQR:1-3) vs. 4 (IQR:3-6)], 90 [median mRS-score: 1 (IQR:0-2) vs. 4 (IQR:2-6)] and 365 days [median mRS-score: 1 (IQR:0-2) vs. 5 (IQR:2-6)]. ESUS was independently (p=0.033) associated with lower admission NIHSS-scores (unstandardized linear regression coefficient: -13.34;95%CI: -23.34, -3.35) on multiple linear regression models. ESUS was not related to 1-year stroke recurrence (HR: 0.22, 95%CI: 0.01-4.06), mortality (HR: 0.25, 95%CI: 0.02-4.36) and functional improvement (1-point shift in mRS-scores; cOR: 1.47, 95%CI: 0.59-3.70) on multivariable analyses. Conclusions: ESUS cases represented 8% of CS patients in this population-based study. Despite the fact that ESUS was independently related to lower admission stroke severity, there was no association of ESUS with long-term outcomes.