Abstract Number ‐ 49: Risk of HT with Early DOACs after Acute Ischemic Stroke: A Pooled Analysis

Introduction The risk of hemorrhagic transformation (HT) in the early phase of acute ischemic stroke (AIS) remains unknown, leading to potential unnecessary delays in initiation of anticoagulation for secondary stroke prevention. We sought to assess the rate of HT associated withdirect oral anticoagulant (DOAC) initiation within and beyond 48 hours after AIS, using a pooled analysis of available published data. Methods A pooled analysis of 6 studies (4 prospective observational blinded outcome studies and2 randomized trials) of DOAC initiation within 14 days of AIS or transient ischemic attack (TIA) was conducted. The primary endpoint was incident radiographic HT on follow‐up imaging. Secondary endpoints included symptomatic HT, new parenchymal hemorrhage, recurrent ischemic events, extracranial hemorrhage, mortality within the study period, and follow‐up modified Rankin Scale score.The results were reported as odds ratio (OR) andhazard ratio (HR)with 95% confidence interval (CI). Results We evaluated 509 patients; median infarct volume was1.5 (0.1‐7.8) ml, andmedian National Institutes of Health Stroke Scale was2 (0‐3).Incident radiographic HT was seen on follow‐up scan in 34 (6.8%) patients.DOAC initiation within 48 hours from index event was not associated with incident HT (adjusted OR 0.67, [0.30 – 1.50]P = 0.32).No patients developed symptomatic HT.Conversely, 31 (6.1%) patients developedrecurrent ischemic events, 64% of which occurred within 14 days.Initiating a DOAC within 48 hours of onset was associated with a trend towards lower rates of recurrent ischemic events, but this was not statistically significant (HR 0.42, [0.17 – 1.008]P = 0.052). In contrast to HT,recurrent ischemic events were associated with poor functional outcomes (OR = 6.8, [2.84 – 16.24], p< 0.001). Conclusions Initiation of DOAC within 48 hours after stroke was not associated with decreased risk of recurrent ischemic events, or increasedincident risk of HT. Both recurrent ischemic events and incident HT occurred at similar rates.Unlike HT, however, recurrent ischemic events were associated with poor outcomes.