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

Objectives: 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.

Background: The magnitude of postprocedural biomarker elevation representing a clinically meaningful PMI after percutaneous coronary intervention (PCI) is controversial.

Methods: 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.

Results: 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.

Conclusions: 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.