Do silent infarcts modify the effect of thrombolysis for stroke?

OBJECTIVES: Silent brain infarcts (SBI) are a common finding both in stroke-free patients and in patients after a cerebrovascular incident. They are considered a risk factor for subsequent symptomatic strokes. However, their influence on outcome in stroke patients treated with thrombolysis is not established. Our aim was to identify the prevalence of SBI in acute ischaemic stroke patients undergoing routine intravenous thrombolysis and evaluate the association between their presence on pretreatment computed tomography (CT) and outcome. MATERIAL AND METHODS: We systematically reviewed CT images and clinical records of consecutive patients treated with thrombolysis because of a first-ever stroke between 1 November 2003 and 31 July 2009 in a single stroke centre. We have analysed the frequency of SBI and their influence on outcome. RESULTS: Silent brain infarcts were present on 82/175 (47%) baseline CT scans. Patients with SBI were significantly older (74 vs 67 years), and more frequently had diabetes (19.5% vs 11.8%) and hyperlipidaemia (37.8% vs 21.5%). There were no significant differences in the ratio of ICH (18.3% vs 14.0%), 3-month mortality (24.7% vs 15.1%) and death or disability (50.6% vs 40.9%), which was also confirmed in a multivariate analysis adjusted for other clinical variables. CONCLUSIONS: In this study, SBI were not associated with increased risk of ICH nor worse outcome after treatment with rt-PA for stroke. SBI should not be considered an argument against initiating thrombolysis, but further studies are needed to fully understand their association with thrombolysis for stroke.