Abstract 12640: Discharge Warfarin is Underused in High Risk Atrial Fibrillation Patients With Myocardial Infarction
Background: ACC/AHA/ESC atrial fibrillation (AF) guidelines recommend the use of warfarin therapy according to patient's risk of stroke assessed by the CHADS2 score, yet the combination of warfarin with antiplatelet medications after acute myocardial infarction (AMI) is challenging. We explored the use of antithrombotic drug combinations in AF patients at discharge following AMI in contemporary practice.
Methods: We examined 69,255 STEMI and NSTEMI patients from 309 ACTION Registry-GWTG hospitals from July 1, 2008, to September 30, 2009. Only those patients who had AF in the 2 weeks prior the index MI admission were included in these analyses (N=4, 947). Discharge antithrombotic therapy use in the absence of contraindications at hospital discharge was described overall and across levels of CHADS2 stroke risk and bleeding risk.
Results: AF was present in 7.1% of the overall AMI population. Percutaneous coronary intervention (PCI) was performed in 36.3% of these AF patients. Use of antithrombotic therapy at discharge stratified by CHADS2 score is shown (Figure). At discharge, although there was a significant increase in use observed across CHADS2 score (P<0.0001), warfarin was still used in just 41.4% of the AF patients; also, 32.5% were already taking warfarin, prior to admission. At discharge, warfarin was used in 37.9%, 42.6%, and 41.6% of the patient at low, moderate, and high risk of bleeding, respectively, showing no variation across bleeding risk (P=0.31). Triple therapy, defined as the combination of aspirin, clopidogrel, and warfarin, was used in a small minority (14.6%).
Conclusions: Less than half of MI patients with recent AF receive warfarin at discharge. Although the prescribing of warfarin is higher with an increase in CHADS2 score, it does not seem to be influenced by bleeding risk. This highlights uncertainty in practice about antithrombotic strategies for patients with both AF and acute MI.
- © 2010 by American Heart Association, Inc.