Presentation and natural history of internal carotid artery occlusion

This retrospective study was undertaken to investigate the effect of presenting neurologic symptoms, vascular risk factors, and degree of contralateral internal carotid artery stenosis on subsequent stroke and death rates of patients with internal carotid artery occlusion (ICO).

One hundred sixty-seven patients with ICO were evaluated over a 5-year period. Mean follow-up was 39 months. Initial symptoms 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 strokes occurred ipsilateral to the ICO.

During follow-up 54 (32%) patients died, 10 (19%) of stroke and 22 (41%) of heart disease. The 5-year cumulative survival rate was 63%. Subsequent neurologic events occurred in 26% of the patients. Thirty patients (18%) had a stroke during follow-up, of which 20 (67%) occurred ipsilateral to the ICO. The 5-year stroke-free rate was 76%. Patients who had a stroke had a less favorable 4-year stroke-free rate (67%) than those who had transient 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 towards 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 reduce the long-term stroke morbidity rate (p = 0.10) on the operated side in patients with 80% to 99% contralateral stenosis but did not perceptibly improve stroke-free rates on the occluded side or in patients with 50% to 79% stenosis.

Patients with ICO have a variable prognosis. There is a significant incidence of subsequent stroke, which seems to be related to the presenting neurologic event and the degree of stenosis in the contralateral internal carotid artery.