Acute stent thrombosis after primary percutaneous coronary intervention: insights from the EUROMAX trial (European Ambulance Acute Coronary Syndrome Angiography).

OBJECTIVES This study sought to determine clinical, procedural, and treatment factors associated with acute stent thrombosis (AST) in the EUROMAX (European Ambulance Acute Coronary Syndrome Angiography) trial. BACKGROUND Bivalirudin started during transport for primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction significantly reduced major bleeding compared with heparin with or without glycoprotein IIb/IIIa inhibitors (GPI), but it was associated with an increase in AST. METHODS We compared patients with (n = 12) or without AST (n = 2,184) regarding baseline, clinical, and procedural characteristics and antithrombotic treatment strategies (choice of P2Y12 inhibitor, post-primary PCI bivalirudin infusion dose [0.25 mg/kg/h, or BIV-LOW] vs. [1.75 mg/kg/h, or BIV-PCI] vs. heparin ± GPI). Logistic regression was performed to identify independent correlates of AST. RESULTS The overall AST rate was 0.6% and was higher with bivalirudin than with heparin ± GPI (1.1% vs. 0.2%; p = 0.007). Median time to AST was 2.3 h (interquartile range: 1.9 to 2.8 h). Patients with AST had less hypertension (2 of 14 [14.0%] vs. 961 of 2,182 [44.0%]; p = 0.03), and more frequently received GPI (11 of 14 [78.6%] vs. 880 of 2,183 [40.3%]; p = 0.004). Multivariate analysis using Firth penalized maximum likelihood estimation found hypertension (odds ratio [OR]: 0.24, 95% confidence interval [CI]: 0.07 to 0.92; p = 0.037) and BIV-LOW (OR: 5.8, 95% CI: 1.5 to 22.2; p = 0.010) predictive of AST. Choice of P2Y12 inhibitor had no impact on AST. Compared with heparin ± GPI, AST rates were higher for BIV-LOW (11 of 670 [1.6%] vs. 2 of 947 [0.2%]; p = 0.008), but not different for BIV-PCI (1 of 244 [0.4%]; p = 0.588). CONCLUSIONS In this post-hoc analysis from EUROMAX, AST occurred very early and was not mitigated by the novel P2Y12 inhibitors. Prolonging the bivalirudin infusion at the PCI dose (but not at a lower dose) appeared to mitigate the risk of AST.