SILENT INFARCTION IN ACUTE STROKE PATIENTS - PREVALENCE, LOCALIZATION, RISK-FACTORS, AND CLINICAL-SIGNIFICANCE - THE COPENHAGEN STROKE STUDY

Background and Purpose Our objective was to study age-specific prevale nce, computed tomographic (CT) characteristics, risk factors, and the prognostic influence on stroke outcome of silent infarction in acute s troke patients. Methods The study was prospective and community-based and included 801 acute stroke patients, of whom 587 had first-ever str oke. A CT scan was performed in 500 (85%) of the 587 patients with fir st-ever stroke. CT was reviewed blindly, and infarcts were classified according to patient history as silent or symptomatic. Patients were e valuated initially with the Mini-Mental State Examination (MMSE) and w eekly with both the Scandinavian Stroke Scale (SSS) and the Barthel In dex (BI) from the onset of stroke to completion of rehabilitation. CT characteristics, risk factors, and stroke outcome were compared in str oke patients with and without silent infarction. Results The prevalenc e of silent infarction in patients with first-ever stroke and recurren t strokes was similar, at 29% (group aged 0 to 54 years, 16%; 55 to 64 years, 22%; 65 to 74 years, 30%; 75 years or older, 33%). Silent infa rcts were small and subcortical. Independent risk factors were increas ing age (odds ratio [OR], 1.95 per 25 years; confidence interval [CI], 1.19 to 3.15), hypertension (OR, 1.75; CI, 1.13 to 2.70), claudicatio n (OR, 1.74; CI, 1.01 to 3.00), and male sex (OR, 1.72; Cl, 1.12 to 2. 64); other stroke risk factors such as atrial fibrillation and former transient ischemic attack were not independent risk factors. Patients with and without silent infarction did not differ in frequency of pres troke home care (P=.2), MMSE (P=.56), initial BI (P=.62) and SSS score (P=.08), BI (P=.85) and SSS score (P=.75) after completion of rehabil itation, or in the speed of recovery (P=.85). Length of hospital stay, mortality rate, and discharge rate to nursing home also did not diffe r between the two groups. Conclusions This community-based study shows that silent infarction in stroke patients is more related to certain stroke risk factors than others and that silent infarction does not se em to influence the prognosis of stroke.