Abstract 12067: Remaining High Risk of Adverse Outcome and Undertreatment with Anticoagulants at Atrial Fibrillation in Acute Myocardial Infarction
Background Increased use of percutaneous coronary intervention (PCI) and dual antiplatelet treatment have improved overall outcome in acute myocardial infarction (MI). However, eventual changes in outcomes in patients with atrial fibrillation (AF) in MI are unclear because of the added need for oral anticoagulation with an inherent risk of bleeding.
Objective To evaluate the occurrence of AF in MI, use of antithrombotic treatment at discharge and their effect on 1-year outcome and to assess changes in treatments and outcomes through 1998-2007 in the Swedish acute MI registry.
Method A total of 117655 consecutive hospital survivors of MI in Sweden between 1998-2007 was the basis for this study. Baseline characteristics and in-hospital treatments were recorded. Long-term outcome was obtained from public health care registries. Primary 1-year outcome (stroke, reinfarction or death) was related to antithrombotic treatments at discharge by Cox multivariable regression analysis. Results in the AF group AF was documented in 18709 (15.9%) with a slight decrease over time (16.7% 1998-99; 14.8% 2006-07). New AF was associated with older age, congestive heart failure and STEMI/LBBB. Warfarin at discharge was prescribed in 21.2% without any relation to risk of stroke (CHADS2 score: 0, 23.1%; 1, 18.8%; ≥ 2, 22.1%) and with a minor increase in prescription over time (20.5% 1998-99; 22.8% 2006-07). Clopidogrel was prescribed in 26.0% with an increase from 3.0% to 51.6% and aspirin in 76.2% with an increase from 74.2% to 80.2% during the same period. The relative risk of primary outcome was high if AF compared to sinus rhythm (RR 1.77; 95% CI 1.73-1.81; p < 0.001) with only a marginal absolute decrease in occurrence from 39.5% to 37.4% over time. Antithrombotic treatments were associated with a lower risk of primary outcome, for warfarin adjusted hazard ratio, HR 0.76; 95% CI 0.70-0.82; p < 0.001, clopidogrel HR 0.87; 95% CI 0.81-0.93; p < 0.001 and aspirin HR 0.87; 95% CI 0.82-0.93; p < 0.001.
Conclusion AF remains common and associated with poor long-term outcome in patients with MI despite major changes in treatments over the last 10 years. However, Warfarin use is still low despite its association with a reduction in stroke, MI and death.
- © 2011 by American Heart Association, Inc.