The ASCOD Phenotyping of Embolic Strokes of Undetermined Source

Various pathogenesis are presumed to be involved in the etiology of embolic stroke of undetermined source (ESUS), which has a high recurrence rate, and much remains unknown about the clinical subtype of recurrent stroke. The purpose of this study was to clarify the pathogenesis of ESUS using the ASCOD classification for ESUS patients and to examine the factors involved in the recurrence of ischemic stroke.

The subjects of this study were 236 of these patients who fulfilled the criteria for ESUS. The rate of stroke recurrent, subtype of recurrent ischemic stroke, and new-onset atrial fibrillation (AF) in these patients were surveyed retrospectively, and each patient was graded for the A, S, and C categories of the ASCOD classification.

Ischemic stroke recurred in 32 patients during the follow-up period (7 days to 12.9 years [median 54.3 months]), and new-onset AF was seen in 44 (18.6%) patients. The most subtype of recurrent ischemic stroke was ESUS again (19 patients). Multivariate analysis with a Cox proportional hazards model, the S score (hazard ratio 5.21; 95% confidence interval (CI) 2.38-11.42; P < .001) and the number of A, S, C categories (hazard ratio 1.90; 95% CI 1.14-3.10; P = .013) were factors significantly related to recurrent ischemic stroke.

Assessment of comorbid conditions in ESUS patients based on the ASCOD classification may be useful in predicting the likelihood of recurrence of ischemic stroke.