Long-term mortality and stroke morbidity after superficial temporal artery-middle cerebral artery bypass operation.

Among 239 patients with transient ischemic attacks, mild stroke, or transient monocular visual symptoms who had superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass, no deaths occurred during the operation or within 30 days thereafter. After the first month, mortality on an actuarial basis was 3% per year. Survival at 5 years was 84% in comparison with an expected survival of 89% for persons of comparable age and sex in a general population. Among the 25 deaths that occurred during follow-up, 2 were due to stroke and 16 to cardiac causes. Of 28 strokes that occurred, 5 occurred during operation or that same day, and 3 others occurred within 30 days postoperatively. Thereafter, strokes occurred at the rate of 2.5% per year on an actuarial basis; a third of the strokes occurred contralateral to the surgical site. No difference was found in survival or in survival free of stroke among patients who had proven carotid artery occlusion (N = 157), carotid siphon stenosis (N = 53), or MCA stenosis or occlusion (N = 29). In regard to the probability of stroke, this group of patients compares favorably with population studies of patients with transient ischemic attacks of undetermined cause. When this surgical group was compared with 130 nonsurgical patients who had had ischemic symptoms related to proven internal carotid artery occlusion between 1965 and 1975, however, we could not conclude that the risk of occurrence of stroke was less in patients who had STA-MCA bypass than in the nonsurgical patients.(ABSTRACT TRUNCATED AT 250 WORDS)