Are all cardio-embolic strokes embolic? An autopsy study of 100 consecutive acute ischaemic strokes.

Estimates of the frequency of different types of ischaemic stroke vary widely, particularly those said to be of embolic aetiology. This retrospective autopsy study of 100 acute ischaemic strokes was undertaken to clarify the incidence of cardio-embolic stroke. Criteria for separating cardio-embolic from other forms of stroke were defined. Using these criteria, 26% of acute ischaemic strokes were cardio-embolic, 28% thrombotic, 12% atheromatous and the remainder due to various other causes including hypoperfusion with 11% being of undetermined aetiology. A significantly higher incidence of non-hypertensive cardiac disease was found in the group in whom no thrombus or thrombo-embolus was found at autopsy, suggesting that some of these strokes may have been due to unrecognised cerebral hypoperfusion. Haemodynamic stroke is probably an important and underrecognised form of acute ischaemic stroke.