Novel risk factors for embolic stroke of undetermined source
Recurrent vascular events in embolic stroke of undetermined source may be directly related to history of diabetes mellitus and the Calcification in the Aortic Arch, Age, Multiple Infarction (CAM) score, a recent study finds.
Researchers looked at a cohort of 177 patients (mean age 64.1 years; 72 percent male) to examine relevant factors, including underlying embolic causes, in embolic stroke of unknown source. Recurrent vascular events such as ischaemic stroke, cardiovascular and peripheral artery diseases, and vascular death were retrospectively analysed. Factors evaluated were clinical characteristics, embolic causes on transoesophageal echocardiography, and the CAM score.
The CAM score was calculated based on the degree of aortic arch calcification on chest radiograph (0 to 3 points), age (≥70 years; 1 point), and multiple infarctions on magnetic resonance imaging (multiple infarcts in 1, 2, or ≥3 territories of large intracranial arteries; 1, 2, or 3 points) associated with recurrent vascular events.
During a median follow up of 3.5 years, recurrent vascular events occurred in 18 percent of the patients. The incidence was high in patients with large aortic arch plaques (7.5 percent per person-year).
Significant predictors of recurrent vascular events were diabetes mellitus (hazard ratio [HR], 2.56; 95 percent CI, 1.23 to 5.32; p=0.012) and CAM score grade (HR, 2.29; 1.11 to 4.72; p=0.026).
Embolic stroke of undetermined source is a relatively new clinical construct based on the rationale that embolism may be the underlying mechanism of cryptogenic (of unknown cause) stroke. It is defined as a non-lacunar brain infarct without proximal arterial stenosis or cardioembolic sources, with a clear indication for anticoagulation. Causes include emboli from a cardiac origin (either from structural diseases or for covert atrial fibrillation), emboli originating from arteries (aortic plaques and nonstenotic plaques of extra and intracranial vessels), emboli originating from veins (paradoxical embolism), and emboli originating from tumours. [Lancet Neurol 13:429-38; Ital J Med 2016;10:185-194]