Impact of large periprocedural myocardial infarction on mortality after percutaneous coronary intervention and coronary artery bypass grafting for left main disease: an analysis from the EXCEL trial

The prognostic implications of periprocedural myocardial infarction (PMI) after percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) remain controversial. We examined the 3-year rates of mortality among patients with and without PMI undergoing left main coronary artery intervention randomized to PCI with everolimus-eluting stents vs. CABG in the large-scale, multicentre, prospective, randomized EXCEL trial. By protocol, PMI was defined using an identical threshold for PCI and CABG [creatinine kinase-MB (CK-MB) elevation >10× the upper reference limit (URL) within 72 h post-procedure, or >5× URL with new Q-waves, angiographic vessel occlusion, or loss of myocardium on imaging]. Cox proportional hazards modelling was performed controlling for age, sex, hypertension, diabetes mellitus, left ventricular ejection fraction, SYNTAX score, and chronic obstructive pulmonary disease (COPD). A total of 1858 patients were treated as assigned by randomization. Periprocedural MI occurred in 34/935 (3.6%) of patients in the PCI group and 56/923 (6.1%) of patients in the CABG group [odds ratio 0.61, 95% confidence interval (CI) 0.40-0.93; P = 0.02]. Periprocedural MI was associated with SYNTAX score, COPD, cross-clamp duration and total procedure duration, and not using antegrade cardioplegia. By multivariable analysis, PMI was associated with cardiovascular death and all-cause death at 3 years [adjusted hazard ratio (HR) 2.63, 95% CI 1.19-5.81; P = 0.02 and adjusted HR 2.28, 95% CI 1.22-4.29; P = 0.01, respectively]. The effect of PMI was consistent for PCI and CABG for cardiovascular death (Pinteraction = 0.56) and all-cause death (Pinteraction = 0.59). Peak post-procedure CK-MB ≥10× URL strongly predicted mortality, whereas lesser degrees of myonecrosis were not associated with prognosis. In the EXCEL trial, PMI was more common after CABG than PCI, and was strongly associated with increased 3-year mortality after controlling for potential confounders. Only extensive myonecrosis (CK-MB ≥10× URL) was prognostically important.