P4575Utility of post-procedural anticoagulation after primary percutaneous coronary intervention for STEMI: cardiac magnetic resonance and 2D-echocardiographic findings

Abstract

Background: Controversy exists as to whether and how long anticoagulation is necessary after primary percutaneous coronary intervention (PCI) in the era of current ST-segment elevation myocardial infarction (STEMI). Purpose: Our aim was to study the impact of prolonged (>24 hours) or brief (≤24 hours) anticoagulation on infarct size and microvascular obstruction (MVO) assessed by cardiac magnetic resonance (CMR) at 30 days, and on 2D-echocardiographic findings at 1 year in patients with STEMI underwent primary PCI from the INNOVATION (Impact of Immediate Stent Implantation Ver- sus Deferred Stent Implantation on Infarct Size and Microvascular Perfusion in Patients With ST-Segment Elevation Myocardial Infarction) randomized trial (NCT02324348). Methods: Among 114 patients (age: 59.5±11.8 years, 83.3% men) enrolled in the trial, 76 (66.7%) received prolonged anticoagulation (median duration 72.6 hours) and 38 (33.3%) received a brief (median duration 5.0 hours). CMR could be evaluated in 105 (92.1%) patients, and evaluable 2D-echocardiography results were present in 89 (78.1%) patients. Left ventricular remodeling was defined as a ≥20% increase in end-diastolic volume at the 1 year follow-up. Results: Patients with prolonged anticoagulation were significantly younger; more likely to have lower level of glucose and have single-vessel coronary disease; and more likely to be treated with glycoprotein IIb/IIIa inhibitors (abciximab). However, complete revascularization and complete ST-segment resolution were significantly less achieved in patients with prolonged anticoagulation. After adjusting for differences in baseline variables, prolonged anticoagulation did not reduce larger infarct size (defined as >75 percentile of infarct size, 19.7% [prolonged anticoagulation] versus 35.6% [brief], adjusted odds ratio [OR]: 0.589, 95% confidence interval [CI]: 0.215-1.610, p=0.303), nor cut the incidence of MVO (50.7% versus 52.9%, adjusted OR: 0.869, 95% CI: 0.319-2.358, p=0.782). The rate of TIMI (Thrombolysis In Myocardial Infarction) major bleeding during in-hospital periods was not significantly different between the 2 groups. Also, patients who received prolonged or brief anticoagulation after primary PCI experienced similar rate of left ventricular ejection fraction <35% (3.2% versus 7.4%, adjusted OR: 0.347, 95% CI: 0.025-4.712, p=0.426), left atrial volume index >34 mL/m2 (30.6% versus 25.9%, adjusted OR: 1.484, 95% CI: 0.392-5.618; p=0.674), and left ventricular remodeling (24.2% versus 14.8%, adjusted OR: 1.493, 95% CI: 0.363-6.135, p=0.579) evaluated by 2D-echocardiography at 1 year. Conclusion: These data suggest that prolonged anticoagulation may not provide benefits after successful primary PCI in patients with STEMI. Therefore, routine post-procedural prophylactic anticoagulation after primary PCI should not be recommended unless a well-established indication is present.