Author + information
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). Our aim was to study the impact of prolonged (>24 hours) or brief (≤24 hours) anticoagulation on infarct size (IS) 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 who underwent primary PCI in the INNOVATION randomized trial (NCT02324348).
Among 114 patients 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 (LV) remodeling was defined as a ≥20% increase in end-diastolic volume at the 1 year follow-up.
Patients with prolonged anticoagulation were significantly younger, had lower level of glucose, and were more likely to have single-vessel coronary disease. However, complete revascularization was less often achieved in patients with prolonged anticoagulation; a prolonged anticoagulation was associated with lower rate of complete ST resolution. After adjusting for differences in baseline variables, prolonged anticoagulation did not reduce larger IS (defined as >75th percentile of IS, 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). Also, patients who received prolonged or brief anticoagulation after primary PCI experienced similar rate of LV 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 >32 mL/m2 (38.7% versus 29.3%, adjusted OR: 1.484, 95% CI: 0.392-5.618; p=0.674), and LV 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.
These data suggest that prolonged anticoagulation for routine prophylaxis may not provide benefit after successful primary PCI in patients with STEMI. Therefore, routine post-procedural anticoagulation after primary PCI should not be recommended unless a well-established indication is present.