In the 30 min round-table discussion video on ESUS, stroke experts (Valeria Caso, Perugia, Danilo Toni, Rome, and Martin Grond, Siegen) discuss the definition of ESUS, diagnostic workup of ischemic stroke and potential implications of the ongoing trials in ESUS.

Embolic stroke of undetermined source (ESUS) is a type of ischemic stroke with unknown origin, i.e. for which no probable cause can be identified after standard diagnostic evaluation. In contrast, the term ‘cryptogenic stroke’ is less well-defined and includes strokes with unknown sources which have not been fully evaluated or have more than one potential cause. About 1 in 6 ischemic strokes is an ESUS. Patient who suffer from ESUS tend to be slightly younger than stroke patients in general and strokes are less severe on average. However, the risk of stroke recurrence after ESUS is high: Within 5 years, nearly 1 in 3 patients may again suffer another stroke.

Diagnostic workup of stroke to identify ESUS needs to exclude lacunar strokes (i.e. occlusion of small vessels penetrating the brain), large atherosclerosis and major cardioembolic risk factors such as atrial fibrillation. Minimum diagnostic assessment of patients with ischemic stroke therefore comprises brain imaging (CT or MRI), imaging of the large arteries supplying the brain with blood, and a cardiac examinations, including echocardiography and ECG monitoring for a minimum of 24 h to exclude atrial fibrillation. For secondary stroke prevention after ESUS, antiplatelets such as aspirin are recommended.

However, ESUS is believed to originate in many cases from cardiac sources such as undetected atrial fibrillation or minor-risk cardioembolic sources such as valve abnormalities. Anticoagulation might therefore be a more effective treatment to reduce recurrence risk after ESUS. This strategy is currently being tested against aspirin in large randomized trials for which results are expected in 2018. They may lead to new secondary prevention strategies for ESUS.

Valeria Caso, President, European Stroke Organization, Stroke Unit, Santa Maria della Misericordia Hospital, University of Perugia, Perugia, Italy

Danilo Toni, Director, Emergency Department Stroke Unit, University of Rome, Sapienza, Italy
Martin Grond, Director, Neurology Clinic, St. Josef-Hospital, Siegen, Germany
Please click here to view video.