Ischaemic stroke of undetermined cause

Abstract

The definition of cryptogenic stroke or stroke of undetermined origin is affected by the current knowledge of the cause and pathogenesis of stroke and by the availability, comprehensiveness, quality, and timeliness of the ancillary investigations undertaken to discover the cause of the stroke. In The Lancet Neurology, Linxin Li and colleagues report findings from a populationbased study of the burden, outcome, risk factors, and long-term prognosis of cryptogenic stroke in patients with a first transient ischaemic attack (TIA) or ischaemic stroke. They found that of 2555 first ischaemic events, 812 (32%) were cryptogenic. The study shows that the prognosis of cryptogenic stroke and the risk of recurrence are similar to those of large artery disease and small vessel disease. For example, death or dependency at 6 months was similar after cryptogenic stroke compared with large artery and small vessel subtypes combined (23% vs 27%; p=0·26), as was the 10-year risk of recurrence (32% vs 27%; p=0·91). Secondary stroke prevention must be similarly aggressive and appropriate in stroke with and without identified cause. The findings from this Article question the role of paroxysmal atrial fibrillation as the major cause of cryptogenic stroke, which contrasts with the present enthusiasm for the use of technology to detect paroxysmal atrial fibrillation and for the possibility to prevent recurrent cryptogenic stroke with anticoagulants.