By Matthew E. Fink, MD
Louis and Gertrude Feil Professor and Chair, Department of Neurology, Associate Dean for Clinical Affairs, New York-Presbyterian/Weill Cornell Medical College
Dr. Fink Reports no financial relationships relevant to this field of study.
SOURCE: Veltcamp R, Pearce LA, Korompoki E, et al. Characteristics of recurrent ischemic stroke after embolic stroke of undetermined source: Secondary analysis of the randomized clinical trial. JAMA Neurol 2020;77:1233-1240.
Twenty percent to 40% of ischemic strokes are classified as cryptogenic, meaning a specific cause cannot be identified. A subset of those have been classified by some investigators as embolic stroke of undetermined source (ESUS). However, this remains a controversial category and classification. ESUS is defined by specific neuroimaging features, other diagnostic tests, and exclusion of certain causes. The annual stroke recurrence rate is about 5%, and these investigators undertook this study to try to learn more about the etiology of recurrent stroke.
The investigators performed a secondary analysis of the randomized trial that was conducted from 2014 to 2017 comparing the efficacy and safety of rivaroxiban and aspirin in patients with recent ESUS. During the period of follow up, recurrent ischemic stroke was validated in 309 of 7,213 patients. The recurrent strokes were classified into categories of ESUS or other categories, including cardioembolic, atherosclerotic, lacunar, other determined cause, or insufficient testing. As part of the overall trial, patients had been randomly assigned to receive rivaroxaban 15 mg per day or aspirin 100 mg per day. Diagnostic testing was insufficient to classify 39 patients. Of the 240 that could be classified, 58% were identified as ESUS and 42% were other causes, 32% cardioembolic, 23% atherosclerotic, 31% lacunar, and 14% of other determined cause. Atrial fibrillation was found the 9% of the patients with recurrent ischemic stroke and this was associated with worse morbidity and mortality. The risk of recurrence did not differ significantly by subtype between the two treatment groups. For all groups, infarct location was more often in the left hemisphere, 54% vs. 46%, or in the brainstem or cerebellum, 14% vs. 9%. In conclusion, most recurrent strokes are once again categorized as ESUS. No additional information was found regarding specific etiologies in this group of ischemic stroke patients of uncertain cause.