Embolic Stroke of Undetermined Source in Latin America A Review

Background: Stroke is a major health concern throughout Latin America. As elsewhere, no precise cause can be determined for a substantial portion of strokes. In 6 studies since 2010 in the region, 16% to 43% of ischemic strokes were identified as cryptogenic. The term embolic stroke of undetermined source (ESUS) has been proposed as more clinically useful and positively defined than the vague term cryptogenic. The epidemiology of ESUS in Latin America is largely unknown. Review Summary: This article aims to provide a description of the epidemiology of ESUS in Latin America and practical information regarding available diagnostic procedures and current guidelines. Atrial fibrillation (AF) is a significant risk factor for stroke, observed in approximately 10% of Mexican and Brazilian stroke patients. Previously unknown AF has been detected through extended monitoring in numerous studies of stroke patients, including 8% of patients in an Argentinian study, and is a possible contributing cause of ESUS. External or implantable outpatient cardiac monitoring has shown increased diagnostic yield for the detection of intermittent AF versus standard cardiac monitoring, but is infrequently used in Latin America. Conclusions: Undiagnosed AF is likely to contribute significantly to cryptogenic stroke and ESUS. Research is needed to continue evaluation of the optimum means of identifying clinically relevant occult AF. In view of the thromboembolic mechanism of ESUS, anticoagulant therapy may prove useful in prevention of recurrence. Ongoing trials are evaluating use of dabigatran, rivaroxaban, or apixaban versus aspirin for reducing the risk of recurrent stroke in patients with previous ESUS.