Impact of silent infarction on the outcome of stroke patients

Silent infarcts (SIs) are commonly found on brain computed tomography (CT) or magnetic resonance imaging (MRI) among elderly subjects, but their risk factors and impact on outcome in stroke patients are unknown. We evaluated the prevalence, risk factors and impact of SIs on the outcome of patients admitted with first-ever ischemic stroke or transient ischemic attack (TIA).

A prospective study of 446 patients admitted consecutively to the neurology service with a diagnosis of TIA or stroke between July 2003 and June 2005, including 226 without any history of prior TIA or stroke. All patients underwent brain CT on the day of admission to the hospital. Risk factors analyzed included age, history of hypertension, diabetes mellitus, cardiovascular disease or stroke, smoking habit and alcohol use. Cholesterol and triglyceride levels were measured on the second day of admission. We monitored these patients for 24 months after stroke onset.

The frequency of SIs among the 226 patients with first-ever stroke or TIA was 20%. Most of the SIs were small and deep. Small-artery disease was more frequently observed in patients with SIs. Age, hypertension, diabetes mellitus, hypercholesterolemia, hypertriglyceridemia, alcohol use, smoking habits and atrial fibrillation did not significantly differ between patients with SIs and those without SIs. During the 24-month follow-up period, the frequency of recurrent stroke was higher in patients with SIs than those without SIs. The mortality rate was higher in patients without SIs than those with SIs. The interval from stroke onset to rehospitalization was shorter in patients without SIs than in those with SIs.

The study showed a higher frequency of small artery disease in patients with SIs. First-ever stroke patients with SIs should be considered at high risk for recurrent stroke.