Implications of Periprocedural Myocardial Biomarker Elevations and Commonly Used MI Definitions After Left Main PCI

The aim of this study was to: 1) assess the relationship of different thresholds of creatine kinase-myocardial band (CK-MB) and cardiac troponin with subsequent mortality; and 2) evaluate the prognostic significance of periprocedural myocardial infarction (PMI) according to various definitions of myocardial infarction in patients with left main (LM) coronary artery disease.The magnitude of postprocedural biomarker elevation representing a clinically meaningful PMI after percutaneous coronary intervention (PCI) is controversial.A total of 4,013 consecutive patients undergoing LM PCI at a single center from January 2004 to December 2016 were enrolled. CK-MB and cardiac troponin I (cTnI) were routinely collected at baseline and at frequent intervals between 8 and 48 hours after PCI. The primary and secondary outcomes were the covariate-adjusted 3-year rates of cardiovascular (CV) and all-cause mortality, respectively.The 3-year rate of CV mortality progressively increased with higher peak CK-MB values. CV mortality was first independently predicted by postprocedural CK-MB 3 to 5 times the upper reference limit (URL) (adjusted hazard ratio [aHR]: 2.93; 95% confidence interval [CI]: 1.02-8.40), whereas all-cause death was independently predicted only by CK-MB ≥ 10 × URL (aHR: 3.25; 95% CI: 1.37-7.70). In contrast, no level of peak postprocedural cTnI was associated with CV or all-cause death. PMI by the Society for Cardiovascular Angiography and Interventions (SCAI), Academic Research Consortium-2 (ARC-2), and fourth universal definition of myocardial infarction (UDMI) occurred in 1.3%, 3.1%, and 5.1% of patients, respectively. The SCAI definition was significantly associated with 3-year CV mortality (aHR: 4.93; 95% CI: 1.92-12.69) and all-cause mortality (aHR: 3.11; 95% CI: 1.33-7.27), whereas the ARC-2 and fourth UDMI definitions were not.In a large cohort of consecutive patients undergoing LM PCI, intermediate (≥3 × URL) and high (≥10 × URL) levels of peak postprocedural CK-MB independently predicted 3-year CV and all-cause mortality, respectively, whereas even large elevations of post-PCI cTnI did not. The SCAI definition (but not the ARC-2 or fourth UDMI) of PMI was independently associated with mortality after LM PCI.