Atherosclerotic lesions and mechanisms of cerebral ischaemia.

Main causes of cerebral infarction and focal transient cerebral attacks (TIAs) were evaluated. We distinguish between primary thrombosis, secondary thrombosis, and atherosclerotic embolism (platelet emboli-mixed emboli-atheromatous emboli). As to the haemodynamic significance of atherosclerotic lesions, the stenoses must be very tight, i.e., suppress 80--90% of the arterial lumen, for blood flow to be reduced. In clinical trials such a situation is not common and we rarely have found out that a stenosis has caused an infarct or focal TIA by reducing blood flow.