Pattern and frequency of recurrent transient ischemic attacks.

Objectives. Natural history studies and stroke prevention trials in patients with transient ischemic attacks (TIAs) have focused primarily on stroke or death outcomes and not recurrent TIA, yet treatment decisions are often based on recurrences. This study was undertaken to evaluate the frequency and pattern of recurrent TIAs in patients presenting with their first TIA. Methods. We monitored TIA recurrence for an average of 16 months in 47 consecutive patients hospitalized in a tertiary care center within 3 weeks of their first TIA. Treatment in 22 patients was aspirin or ticlopidine alone, and 12 underwent endarterectomy. Remaining patients received warfarin, dipyridamole, or pentoxifylline alone or with aspirin, including two who underwent endarterectomy. Treatment was changed in only four patients during the follow-up period. Results. Thirty-four patients (72%) had more than one TIA; 23 of these (68%) had two to five recurrences and 11 (32%) had more than five TIAs. Nineteen of the 34 patients with multiple TIAs had recurrences within 1 month of the initial TIA. Only four patients (12%) had recurrent TIAs throughout the follow-up period. Stroke occurred in five patients (11%); one patient had a single prior TIA, and the rest had multiple TIAs. No risk factors or treatments predicted which patients had single or multiple TIAs. Conclusions. Most patients have few recurrent TIAs, and recurrences usually occur within the first month of the initial TIA. The patterns of TIA recurrence identified should aid in treating patient and in devising appropriate outcome measures in treatment trials in which TIA is an endpoint.