Abstract 14336: Long-Term Risk of Bleeding and Impact of Non-Therapeutic INRs in Patients Discharged on Triple Antithrombotic Therapy After Hospitalization For Acute Coronary Syndrome
Background: There are limited data on the use of triple antithrombotic therapy (aspirin, clopidogrel, and warfarin) after discharge for acute coronary syndromes or its association with control of INR and bleeding complications.
Methods: We studied consecutive VA patients admitted for ACS who were enrolled in the Cardiac Care Follow-up Clinical Study from October 1, 2005 to January 10, 2009. Patients were stratified into 3 groups: 1) Aspirin+Clopidogrel (A+C); 2) Aspirin+Clopidogrel+Warfarin (A+C+W), and 3) Aspirin+Warfarin (A+W). Medication use was determined by chart abstraction at hospital discharge and by pharmacy dispensing data during follow-up. INR values for patients on warfarin and occurrence of major bleeding after discharge were determined from computerized records. Cox proportional hazards models were constructed to estimate the adjusted risk of major bleeding.
Results: A total of 11,157 patients were discharged on one of the 3 regimens. During a median follow-up of 2.2 years, 528 patients (4.7%) had a major bleed. The unadjusted bleeding rates were highest in the A+W followed by A+C+W and A+C groups (9.0% vs 8.7% vs 3.6%). Using A+C as a reference, the hazard ratio (95% confidence interval) for major bleeding was 1.78 (1.40-2.25) for A+W, and 2.07 (1.66-2.57) for A+C+W (Table). Patients on warfarin who had therapeutic INRs <50% of visits had a higher risk of bleeding than those with therapeutic INR's >50% of visits (HR 3.49; 95%CI 2.19-5.54).
Conclusion: Compared with dual antiplatelet therapy, the addition of warfarin and INRs outside the therapeutic range was associated with substantially increased risks of major bleeding.
- © 2011 by American Heart Association, Inc.