SILENT CEREBRAL INFARCTION IN PATIENTS ENROLLED IN THE TOAST STUDY

To determine the frequency, location, size, and risk factors for silen t cerebral infarctions (SCIs) on brain CT, we identified 629 patients without a history of previous stroke who were enrolled in a multicente r clinical trial of therapy for acute ischemic stroke. On the baseline CT, 143 patients (22.7%) had SCIs; 34.3% of the lesions were in the r ight hemisphere, 38.5% in the left hemisphere, and 27.3% were bilatera l. The lesion size was <1 cm in 65.7%, and the most common site was th e basal ganglia (48.3%). Patients with SCI were compared with controls without SCI to determine the odds ratios (ORs) for each risk factor. On univariate analysis, race (black versus white) had an OR of 1.80 (9 5% confidence interval [CI], 1.14 to 2.85), male sex an OR of 1.68 (95 % CI, 1.12 to 2.51), and congestive heart failure an OR of 1.88 (95% C I, 1.07 to 3.31). Significant risk factors on multivariate analysis in clude age (OR 1.03 per year, p = 0.0070), male sex (OR 1.78, p = 0.009 4), and race (OR 2.43, p = 0.0004). After including interaction terms with age and hypertension and age, sex, and race, hypertension was als o a significant risk factor.