Frequency and features of embolic stroke of undetermined source in young adults

The sources of emboli in those with embolic stroke of undetermined source may differ in old and young. We assessed the frequency, features and potential embolic sources of younger vs. older embolic stroke of undetermined source patients in the embolic stroke of undetermined source Global Registry.

Cross-sectional study of consecutive patients over age 18 years, with recent ischaemic strokes at 19 centres conducted in 2013-2014. Characteristics of embolic stroke of undetermined source patients who aged ≤50 years were analysed and compared with embolic stroke of undetermined source patients who aged >50 years.

Among 2144 patients with ischaemic stroke, 323 (15.1%, 95% confidence interval: 13.6-16.7%) were ≤50 years old and, 1821 >50 years. 24% (n = 78) of young vs. 15% (n = 273) of older patients met embolic stroke of undetermined source criteria. The mean age of young embolic stroke of undetermined source patients was 40 years (standard deviation +/-9), 33% were women and the most prevalent vascular risk factor was hypertension (38%). Conventional vascular risk factors were less frequent in younger embolic stroke of undetermined source patients. Fewer young embolic stroke of undetermined source patients (63%) had potential minor risk embolic sources identified vs. older embolic stroke of undetermined source patients (77%) (p = 0.02). Stroke severity on admission was similar in younger vs. older patients (National Institute of Health Stroke Scale (NIHSS) 3 vs. 4, p = 0.06).

Young embolic stroke of undetermined source patients comprise an important subset of ischaemic stroke patients around the world. Severity of stroke on admission and 30-day mortality rates are similar among young and older patients. However, there are important differences between younger vs. older embolic stroke of undetermined source patients with respect to risk factors, and potential embolic sources that could affect response to anticoagulants vs. antiplatelet therapies.

This study provides a benchmark for the global frequency and characteristics of young embolic stroke of undetermined source patients and shows consistent high frequency of embolic stroke of undetermined source in young adults.