Importance of Finding Embolic Sources for Patients with Embolic Stroke of Undetermined Source

Abstract

Objective: The concept of embolic stroke of undetermined source refers to cryptogenic strokes caused by either major or minor risks. Although antiplatelet treatments are most often used for secondary prevention of embolic stroke of undetermined source, optimal strategies remain unclear. To determine the ideal treatment strategy for secondary prevention, we investigated embolic sources among patients with embolic stroke of undetermined source. Methods: The study included 292 consecutive patients (135 men, 157 women; mean age: 74.3 ± 11.6 years) diagnosed with cerebral infarction, 27 of whom were diagnosed with embolic stroke of undetermined source (9.2%; 14 men, 13 women; mean age: 70.7 ± 11.5 years). These 27 patients were examined using contrast-enhanced whole-body computed tomography, transesophageal echocardiography, and Holter electrocardiography. We evaluated whether antiplatelet or anticoagulant treatment was preferred based on the embolic source. Results: Embolic sources among patients with embolic stroke of undetermined source included valve calcification (11.1%), left ventricle diastolic dysfunction (18.5%), cancer-associated stroke (25.9%), covert atrial fibrillation (7.4%), aortic arch atherosclerotic plaques (11.1%), paradoxical embolism (3.7%), and sick sinus syndrome (3.7%). Embolic sources remained unidentified in 5 patients (18.5%). Our analysis revealed that 21 of the 27 patients (77.8%) with embolic stroke of undetermined source required anticoagulant therapy for secondary prevention. Conclusion: Although aspirin is the most commonly used antithrombotic drug for embolic stroke of undetermined source, our results suggest that some patients require anticoagulant therapy. Determining embolic sources is important for selecting the appropriate treatment options for this patient population.