EMBOLIC VERSUS NONEMBOLIC CAUSES OF ISCHEMIC STROKE

Determination of the stroke type may be crucial to rational treatment and prediction of outcome. Patients with infarct in the anterior or posterior circulation, and patients with lacunar infarcts may all have different evolution due in part to different stroke mechanisms. Though infarcts in the vertebrobasilar territory may have mainly a nonembolic mechanism, the relative frequency of multiple vertebrobasilar infarcts and the presence of potential cardiac and arterial sources may identify a subgroup of patients with embolism as main stroke mechanism. Brain infarcts of different size and topography may also correspond to different mechanisms. In addition, while the main mechanism of small deep infarct is small-vessel disease associated with hypertension, there is a subgroup of patients in whom the cause is not hypertensive arteriolopathy but large-artery disease or cardiac embolism. Consequently, as a rule, a complete evaluation remains necessary in order to establish the exact stroke mechanism in individual stroke patients.