Prognosis in Patients With Transient Ischemic Attacks

The prognosis on 144 patients with transient ischemic attacks was determined over a minimum period of three years by quantitating, at intervals, the number of attacks and also the neurological disability by means of a disability score, No patients had neurological disability at the initiation of the study. Total cervicocephalic angiography was performed on 93 patients. Seven of the 144 patients were deceased at the end of the three-year period, five of them due to strokes. Seventeen patients (15.6%) developed persistent neurological disability during the three years, with the mean disability score being much higher for the patients with carotid attacks than those with basilar attacks. The cumulative number of attacks in both carotid and basilar groups rose steadily in the first 18 months, with a much larger number of attacks occurring in the basilar group. The attack rate leveled off after 18 months in the carotid group. Attacks tended to be consistent in nature over a period of time. Twenty-eight percent of those patients with basilar attacks and 12.5% of those patients with carotid attacks showed carotid stenosis on angiography. Study of carotid stenosis associated with subsequent neurological disability revealed that increased risk occurred only when carotid stenosis was more than 70%.