Abstract WP411: Asymptomatic Hemorrhage Predicts Delayed Symptomatic Hemorrhage After Alteplase in Acute Ischemic Stroke

Background: Predictors of alteplase associated symptomatic intracranial hemorrhage (sICH) have been identified but there are very limited data on predictors of delayed sICH (> 24 hours from infusion). We hypothesize that asymptomatic hemorrhage on 24 hour brain imaging predicts delayed sICH and that delaying antithrombotic treatment in these patients reduces this risk. Methods: This is a retrospective analysis of a prospective quality improvement database of a comprehensive stroke center. We included all patients with a discharge diagnosis of ischemic stroke who received alteplase. Patients with sICH occurring within 24 hours from alteplase and those whose code status was changed to comfort measures only were excluded. Delayed sICH was defined as any hemorrhage causing neurological deterioration. We compared baseline characteristics, asymptomatic hemorrhage on 24 hour brain imaging, and median time to initiating antithrombotic therapy between patients with and without delayed sICH. Results: Among 606 patients who met our inclusion criteria; mean age was 70 years and 52% were men; 23.8% had asymptomatic hemorrhage on 24 hour brain imaging (CT or MRI) and 12 patients (2%) had delayed sICH. Aspirin was the most common initial antithrombotic (91.2%) followed by plavix (2.6%), and others (3.8%). After adjusting for confounders, asymptomatic hemorrhage on 24 hour brain imaging was associated with increased odds of delayed sICH (OR 5.5, 95% CI 1.52 - 19.87, p = 0.009) but the median time (days) to starting antithrombotic therapy did not differ between those with asymptomatic hemorrhage who developed delayed sICH vs. those who did not [2 (3) vs. 3 (5), p = 0.447). Conclusion: Delayed sICH in patients receiving alteplase is uncommon and asymptomatic hemorrhage is a strong predictor. Delaying initiation of antithrombotic treatment in patients with asymptomatic hemorrhage on 24 hour imaging was not associated with reduced delayed sICH risk. It is possible that other factors such as reperfusion and blood brain barrier disruption are more important determinants of delayed sICH risk as opposed to timing of antithrombotic therapy initiation.