When extracranial carotid stenosis produces a [[transient ischemic attack]] or stroke, artery-to-artery embolism is the predominant mechanism. Asymptomatic significant (>50%) carotid stenosis poses special clinical questions in patients scheduled to undergo general surgical or major cardiovascular operations. ---- Extracranial atherosclerotic disease accounts for up to 15–20% of all [[ischemic stroke]]s