PRESENTATION AND NATURAL-HISTORY OF INTERNAL CAROTID-ARTERY OCCLUSION

Purpose: This retrospective study was undertaken to investigate the ef fect of presenting neurologic symptoms, vascular risk factors, and deg ree of contralateral internal carotid artery stenosis on subsequent st roke and death rates of patients with internal carotid artery occlusio n (ICO). Methods: One hundred sixty-seven patients with ICO were evalu ated over a 5-year period. Mean follow-up was 39 months. Initial sympt oms included transient ischemic attack in 29 patients (17%), stroke in 71 patients (43%), nonhemispheric symptoms in 22 patients (13%), and no symptoms in 45 patients (27%). Ninety percent of the presenting str okes occurred ipsilateral to the ICO. Results: During follow-up 54 (32 %) patients died, 10 (19%) of stroke and 22 (41%) of heart disease. Th e 5-year cumulative survival rate was 63%. Subsequent neurologic event s occurred in 26% of the patients. Thirty patients (18%) had a stroke during follow-up, of which 20 (67%) occurred ipsilateral to the ICO. T he 5-year stroke-free rate was 76%. Patients who had a stroke had a le ss favorable 4-year stroke-free rate (67%) than those who had transien t ischemic attack (92%) or those who originally had no symptoms (89%), p = 0.03 and p = 0.04, respectively. In addition, there was a trend t owards a worse 5-year contralateral stroke-free rate in patients with contralateral stenosis of 50% to 99% (77%) compared with patients with less than 50% contralateral stenosis (94%), p = 0.08. Twenty patients underwent carotid endarterectomy on the nonoccluded side. There were no perioperative strokes or deaths. Carotid endarterectomy seemed to r educe the long-term stroke morbidity rate (p = 0.10) on the operated s ide in patients with 80% to 99% contralateral stenosis but did not per ceptibly improve stroke-free rates on the occluded side or in patients with 50% to 79% stenosis. Conclusion: Patients with ICO have a variab le prognosis. There is a significant incidence of subsequent stroke, w hich seems to be related to the presenting neurologic event and the de gree of stenosis in the contralateral internal carotid artery.