Bleeding after Initiation of Multiple Antithrombotic Drugs, Including Triple Therapy, in Atrial Fibrillation Patients Following Myocardial Infarction and Coronary Intervention: A Nationwide Cohort Study

American Heart Association: August 6, 2012

Background—Uncertainty remains over optimal antithrombotic treatment of patients with atrial fibrillation (AF) presenting with myocardial infarction (MI) and/or undergoing coronary intervention (PCI). We investigated the risk and time-frame for bleeding following MI/PCI in AF patients according to antithrombotic treatment.

Methods and Results—Patients with AF and admitted with MI or for PCI between 2000-2009 (11,480 subjects, mean age 75.6 years [SD±10.3], males 60.9%) were identified by individual level-linkage of nationwide registries in Denmark. Fatal or non-fatal (requiring hospitalization) bleeding was determined according to antithrombotic treatment regimen; Triple therapy (TT) with vitamin K antagonist (VKA) + aspirin + clopidogrel, VKA + antiplatelet (AP), and dual antiplatelet therapy (DAPT) with aspirin + clopidogrel. We calculated crude incidence rates, and adjusted hazard ratios by Cox regression models. Within 1-year, 728 bleeding events were recorded (6.3%); 79 were fatal (0.7%). Within 30 days, rates were 22.6, 20.3, and 14.3 bleeding events per 100 person-years for TT, VKA + AP, and DAPT, respectively. Both early (within 90 days) and delayed (90-360 days) bleeding risk with TT exposure in relation to VKA + AP was increased; hazard ratio 1.47 [1.04;2.08] and 1.36 [0.95;1.95], respectively. No significant difference in thromboembolic risk was observed for TT vs. VKA + AP; HR 1.15 [0.95;1.40]. Read more