Persantine aspirin trial in cerebral ischemia--Part III: Risk factors for stroke. The American-Canadian Co-Operative Study Group.

This third paper from the Persantine Aspirin Trial examines the data to identify risk factors for stroke in persons with a history of carotid territory transient ischemic attacks (TIAs) Fifteen centers in the United States and Canada participated, and 890 subjects were admitted and randomly allocated to either aspirin plus placebo or aspirin plus dipyridamole (Persantine). Persons with the following characteristics were in greater jeopardy for stroke, retinal infarction, or death: older age, history of heart disease, history of peripheral vascular disease, and persisting neurologic deficit from a recent event. Elevated diastolic blood pressure, diabetes, use of estrogen, and smoking were not found to be risk factors. Elevated systolic blood pressure was a risk factor primarily in subjects with a history of heart disease. Estrogen use may actually have had a protective effect for women. This cannot be considered as a report of the natural history of TIA patients; it does identify risk factors in a specific cohort of subjects under treatment.