The causes and prevention of stroke associated with carotid artery surgery.

Four hundred eighty-eight consecutive carotid endarterectomies were performed on 417 patients. Stroke, as a procedure-related complication, occurred in 12 patients, or 2.4 per cent of cases. Five causes of operative or postoperative stroke were identified: 1) operative embolization, 2) postoperative hypertensive episodes with cerebral hemorrhage, 3) technical error, 4) conversion of ischemic infarct to hemorrhagic infarct, and 5) clamp-time ischemia. The use of several modalities evolved as routine in an effort to reduce mortality and morbidity: 1) minimal manipulation of the artery until after cross clamping to prevent microembolization; 2) routine direct arterial blood pressure monitoring and control during and after surgery; 3) routine operative arteriography to detect and correct technical errors at the time of surgery; 4) liberal use of CAT scans preoperatively to avoid surgery on patients with small, unrecognized infarcts; and 5) stump pressure measurement and selective shunting to prevent ischemia during the endarterectomy. The anatomical-pathological combination of a high bifurcation and high plaque is identified as a high-risk situation.