Association Between Intraprocedural Thrombotic Events and Adverse Outcomes After Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction (a Harmonizing Outcomes With RevasculariZatiON and Stents in Acute Myocardial Infarction [HORIZONS-AMI] Substudy)

The present study sought to determine the extent to which adverse angiographic events encountered during percutaneous coronary intervention for ST-segment elevation myocardial infarction (STEMI) are associated with adverse clinical outcomes. Patients with STEMI represent a cohort at particularly high risk of intraprocedural thrombotic events (IPTEs). The overall frequency and implications of IPTEs occurring in patients with STEMI have not been systematically quantified in previous studies. A total of 3,163 patients undergoing primary percutaneous coronary intervention with stent implantation for STEMI in the Harmonizing Outcomes with RevasculariZatiON and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial underwent detailed frame-by-frame core laboratory angiographic analysis to assess IPTEs. The clinical outcomes at 30 days were compared between the patients with and without IPTEs. IPTEs, defined as the development of new or increasing thrombus, abrupt vessel closure, no reflow, slow reflow, and distal embolization at any point during the procedure, occurred in 386 patients (12.2%). The independent predictors of IPTE were thrombus at baseline, lesion length, and randomization to bivalirudin; the patients with IPTEs were also more likely to receive bailout glycoprotein IIb/IIIa inhibitors and unplanned thrombectomy. Compared with patients without IPTEs, the patients with IPTEs had higher 30-day rates of composite major adverse cardiovascular events (death, myocardial infarction, ischemic target vessel revascularization, and stroke; 7.8% vs 4.2%, p = 0.002), major bleeding not related to coronary artery bypass grafting (11.8% vs 6.5%, p0.001), and all-cause death (4.2% vs 1.8%, p = 0.002). On multivariate analysis, IPTEs were independently associated with 30-day major adverse cardiovascular events, major bleeding, and death. In conclusion, the development of IPTEs in patients undergoing primary percutaneous coronary intervention for STEMI was associated with subsequent adverse outcomes, including major adverse cardiovascular events, major bleeding, and death. Additional studies of strategies to decrease the occurrence of IPTEs are warranted.