Background: Prehospital administration of P2Y12 receptor antagonists to patients with ST-elevation myocardial infarction (STEMI) is supported by guidelines and is a common practice despite the lack of definite evidence for its benefit.
Methods: Using data from the Swedish Coronary Angiography and Angioplasty Registry on procedures between 2005 and 2016 we stratified all patients who underwent primary PCI due to STEMI in Sweden by whether or not they were pretreated with P2Y12 receptor antagonists. We investigated associations between P2Y12 pretreatment and the risk of adverse outcomes with propensity-scores adjusted mixed-effects logistic regression, which accounted for clustering of patients within hospitals. The primary endpoint was all-cause death within 30 days. Secondary endpoints were IRA (infarct-related artery) occlusion, 30-day stent thrombosis, in-hospital bleeding, neurological complications and cardiogenic shock.
Results: In total, 44,804 patients were included. They were treated with clopidogrel (N=26,136, 58.3%), ticagrelor (N=15,792, 35.3%), or prasugrel (N=2,352, 5.3%); 37,840 (84.5%) were pretreated, and 30,387 (67.8%) had IRA occlusion. At 30 days, there were 2,488 (5.6%) deaths and 267 (0.6%) stent thromboses. Pretreatment was not associated with better survival (OR 0.1.07; 95% CI 0.94-1.22; P=0.313) at 30 days, reduced IRA occlusion (OR 1.01; 95% CI 0.95-1.08; P=0.635), or decreased stent thrombosis (OR 0.99; 95% CI 0.69-1.41; P=0.941), or higher risk of in-hospital bleeding (OR 1.04; 95% CI 0.89-1.23; P=0.604), or neurological complications (OR 0.66; 95% CI 0.38-1.30; P=0.129). We found no difference in risk of cardiogenic shock between the groups (OR 0.91; 95% CI 0.78 - 1.07; P=0.264)
Conclusion: Pretreatment of STEMI patients with P2Y12 receptor antagonists was not associated with improved clinical outcomes.