Prognostic Implications of Evolving Universal Definitions of Periprocedural Myocardial Infarction in Patients With Acute Coronary Syndrome.

Background The universal definition of percutaneous coronary intervention (PCI)-related myocardial infarction (MI) has been substantially updated over the years, including an increase in the biomarker threshold (from 3 to 5 times the upper reference limit) and the introduction of ancillary criteria such as ischemic symptoms and electrocardiographic or angiographic complication. The impact of these changes in patients with acute coronary syndrome (ACS) remains incompletely understood. The objective of this study was to compare prognostic implications of evolving universal definitions of PCI-MI in a large cohort of patients with ACS from the MATRIX trial (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of AngioX).Methods Among 6724 patients undergoing PCI in the MATRIX trial, PCI-MI was prospectively adjudicated by the second, third and fourth universal definition of MI (UDMI). The 2 co-primary end points were all-cause and cardiovascular death (from 24 hours to 1 year after PCI) in patients with non-ST-segment-elevation ACS. Hazard ratios and 95% CIs were generated for primary and secondary end points with the use of Cox proportional hazards time-to-event analyses for each MI definition.Results PCI-MI occurred in 590 patients (9%) with the second UDMI, 193 (3%) with the third UDMI, and 182 (3%) with the fourth UDMI applied in the overall ACS population. Among patients with non-ST-segment-elevation ACS, the corresponding figures were 15%, 5%, and 5%. Only PCI-MI defined by the fourth UDMI in patients with non-ST-segment-elevation ACS was associated with increased risks of all-cause (hazard ratio, 2.08 [95% CI, 1.00-4.30]; P=0.048) and cardiovascular (hazard ratio, 2.62 [95% CI, 1.03-6.65]; P=0.043) death. In patients with ST-segment-elevation myocardial infarction, PCI-MI was uncommon (1% to 4% depending on the working definition) and was not associated with increased mortality. In the absence of objective ancillary criteria (electrocardiographic and angiographic complications), isolated troponin elevations up to 20 times the upper reference limit were not associated with increased mortality risk.Conclusions PCI-MI defined according to the fourth UDMI was associated with increased risks of 1-year mortality only in patients with non-ST-segment-elevation ACS. These data support the evolution of the universal definition of PCI-MI.Registration URL: http://www.clinicaltrials.gov; Unique identifier: NCT01433627.