Transient ischemic attacks (TIAs) occur in approximately one of every 15 persons older than 65 years. Evaluation of these patients is rarely possible while the neurologic symptoms are present, making appropriate treatment unclear. Antiplatelet therapy, anticoagulation and, possibly, endarterectomy may be indicated. Johnston and colleagues reviewed the short-term risk of stroke and other adverse events following a TIA and attempted to determine which patients may benefit from more aggressive management.
All patients with a diagnosis of TIA in the emergency department from March 1997 through February 1998 were included in the study. TIA was defined on the basis of World Health Organization criteria as rapidly developed clinical signs of focal or global disturbance of cerebral function lasting fewer than24 hours, with no apparent nonvascular cause. Information about symptoms and treatment plans was recorded. Patients were followed for 90 days after presentation to determine the occurrence of stroke (the primary outcome measure), TIA, death and hospitalization for cardiovascular events.
A total of 1,707 patients were diagnosed with TIA The mean duration of symptoms was 207 minutes. One half of the patients had symptoms at the time of presentation. During the 90-day follow-up period, 180 patients (10.5 percent) had a stroke, 91 of which occurred during the first two days after the TIA Strokes were disabling in 115 patients (64 percent) and fatal in 38 patients (21 percent). Only 7 percent of the strokes were not disabling and did not require hospitalization. Increased risk of stroke was associated with the following factors: older than 60 years, diabetes mellitus, weakness, speech impairment, gait disturbance during the TIA and TIA duration of longer than 10 minutes. The risk of having a stroke increases with each additional risk factor. The percentage of patients who had a stroke within 90 days based on risk factors was as follows: patients with no risk factors had a zero percent chance of having a stroke in the next 90 days; patients with one risk factor, 3 percent; patients with two risk factors, 7 percent; patients with three risk factors, 11 percent; patients with four risk factors, 15 percent; and patients with five risk factors, 34 percent. TIAs recurred in 12.7 percent of patients. Overall, more than 50 percent of adverse events occurred within the first four days after the TIA.
The authors conclude that TIAs are associated with a short-term risk of recurrent TIA, stroke and death. The risk of these events is highest in the days immediately following the TIA Further studies may be needed to develop strategies for prevention and ways to stratify patients on the basis of symptoms.