Prophylactic warfarin therapy after primary percutaneous coronary intervention for anterior ST-segment elevation myocardial infarction

Abstract

Objectives: This study sought to determine the benefits of adding oral anticoagulation therapy in patients with anterior wall ST-segment elevation myocardial infarction (STEMI) patients after primary percutaneous coronary intervention (PCI).

Background: Guidelines suggest adding oral anticoagulation to dual-antiplatelet therapy in patients with STEMI when left ventricular apical akinesis or dyskinesis is present to prevent thromboembolic complications. The benefits of this triple therapy remain unknown.

Methods: We identified patients with anterior STEMI referred (PCI) between July 2004 and June 2010 with apical akinesis or dyskinesis on transthoracic echocardiography. We compared patients who were prescribed warfarin to patients who were not. We excluded patients with left ventricular thrombus, a separate need for oral anticoagulation, and previous intracranial bleeding. The primary outcome was a composite of net adverse clinical events (NACE) consisting of all-cause mortality, stroke, reinfarction, and major bleeding at 180 days.

Results: Among 460 patients who qualified, 131 were discharged on warfarin therapy and 329 without warfarin therapy. Dual-antiplatelet therapy was prescribed for 99.2% of the patients in the warfarin group and for 97.6% of the patients in the no warfarin group (p = 0.46). Compared with patients in the no warfarin group, patients in the warfarin group had higher rates of NACE (14.7% vs. 4.6%, p = 0.001), death (5.4% vs. 1.5%, p = 0.04), stroke (3.1% vs. 0.3%, p = 0.02), and major bleeding (8.5% vs. 1.8%, p < 0.0001). By propensity score analysis, allocation to warfarin therapy was an independent predictor of NACE (odds ratio [OR]: 4.01, 95% confidence interval: 2.15 to 7.50, p < 0.0001). In a separate multivariable analysis, the OR of NACE remained significantly higher compared with patients who were not prescribed warfarin (OR: 3.13, 95% confidence interval: 1.34 to 7.22, p = 0.007).

Conclusions: Our results do not support the addition of warfarin therapy after primary PCI in patients with apical akinesis or dyskinesis.

Keywords: ST-segment elevation myocardial infarction; angioplasty; oral anticoagulation; primary percutaneous intervention.