Admission International Normalized Ratio Levels, Early Treatment Strategies, and Major Bleeding Risk Among Non-ST Elevation Myocardial Infarction Patients on Home Warfarin Therapy: Insights from the NCDR®
Background—Non-ST-segment elevation myocardial infarction (NSTEMI) patients on home warfarin pose treatment concerns, due to potential increased risk of bleeding. The American College of Cardiology/American Heart Association (ACC/AHA) Guidelines suggest holding anticoagulants and initiating antiplatelet therapy among therapeutically anticoagulated NSTEMI patients. Yet little is known about contemporary treatment patterns and bleeding risks in this population.
Methods and Results—We stratified 5,787 NSTEMI patients on home warfarin therapy using data from the NCDR ACTION Registry®-GWTG™ by admission international normalized ratio (INR) levels: subtherapeutic (INR <2), therapeutic (INR 2-3), and supratherapeutic (INR >3). Multivariable logistic generalized estimating equations models were constructed to examine the associations between admission INR level, early antithrombotic treatment and invasive therapy, and risk of in-hospital major bleeding. Among these patients, 46%, 35%, and 19% had subtherapeutic, therapeutic, and supratherapeutic admission INR levels, respectively. Risk of major bleeding was higher among patients with therapeutic (15%, adjusted odds ratio [OR] 1.25, 95% confidence interval [CI] 1.03-1.50) and supratherapeutic anticoagulation (22%, OR 1.60 [1.30-1.97]) compared with the subtherapeutic group (12%). Among patients with admission INR ≥2, 45% were treated with early (within 24 hours) heparin, 35% with early clopidogrel, 14% with early glycoprotein IIb/IIIa inhibitor (GPI), and 36% with early invasive strategy. Early antithrombotic treatment was associated with increased bleeding risk (OR 1.40 [1.14-1.72] for heparin; 1.50 [1.22-1.84] for clopidogrel; 1.82 [1.43-2.32] for GPI); however, an early invasive strategy was not (OR 1.09 [0.86-1.37]). No significant interactions were observed between INR level and use of each early treatment in its association with bleeding.
Conclusions—National patterns of early antithrombotic treatment for NSTEMI patients on home warfarin diverge from expert opinion provided by current practice guidelines. Early antithrombotic treatment was associated with increased bleeding risk, regardless of admission INR level.
- acute coronary syndrome
- non-ST-segment elevation myocardial infarction
- Received July 28, 2011.
- Accepted January 30, 2012.
- Copyright © 2012, American Heart Association, Inc. All rights reserved. Unauthorized use prohibited