Abstract WP114: Effect of Prestroke Aspirin on Infarct Volume

Abstract

Objective: To investigate if prestroke aspirin use affects infarct volume, generally and by subtype. Background: Prestroke aspirin use may reduce initial stroke severity and improve functional outcome at discharge, especially in the large artery atherosclerosis (LAA) stroke. We investigated whether prestroke aspirin use is associated with infarct volume and the effect of prestroke aspirin on infarct volume is different between LAA versus non-LAA strokes. Methods: A total of 4427 patients were included. The association between infarct volume on DWI and prior aspirin use was assessed by multiple linear regression analysis. To adjust a significant imbalance between aspirin users vs. non-aspirin users, the augmented inverse-probability weighting (AIPW) and propensity score matching were used. Results: Mean age was 67.7(SD 12.4) years and 58.7% were male. 19.6% (n=869) took aspirin before stroke. Prestroke aspirin had an inverse relation with log-infarct volume (P = 0.007) and the effect was significantly modified by LAA versus non-LAA strokes (P for interaction = 0.02). In LAA stroke (n=2336), prestroke aspirin use was independently associated with log-infarct volume (standardized beta = -0.047; P = 0.032). In non-LAA stroke (n=2091), prestroke aspirin was not associated with infarct volume (P = 0.27). Using AIPW and propensity score matching, the mean difference of log-infarct volume between prestroke aspirin user versus non-aspirin uses was -0.28 (95% CI -0.52 to -0.04, P = 0.009) and -0.39 (95% CI -0.67 to -0.11, P = 0.02) in LAA strokes. In non-LAA strokes, AIPW and propensity score matching showed that prestroke aspirin use was not associated with infarct volume (P = 0.27 and P = 0.85, respectively). Conclusions: Our results showed that prestroke aspirin use is negatively associated with initial infarct volume on DWI in LAA strokes but not in non-LAA strokes.