Creatine kinase-MB elevation after coronary artery bypass grafting surgery in patients with non-ST-segment elevation acute coronary syndromes predict worse outcomes: results from four large clinical trials

Abstract

To assess the significance of creatine kinase (CK)-MB elevations in outcomes of patients with non-ST-segment elevation acute coronary syndromes (NSTE ACS) who have undergone coronary artery bypass grafting (CABG) surgery. This analysis includes data from 26 465 patients with NSTE ACS enrolled in four major trials. In total, 4626 (17.5%) of patients had CABG within 30 days. Patients were excluded if CK-MB was elevated within 24 h before surgery and there was no CK-MB measured after surgery. Overall, 4401 patients were included in these analyses. The incidence of mortality increased with peak CK-MB ratios of 0-1, >1-3, >3-5, >5-10, and>10x the upper limit of normal measured at the local lab (P<0.001 across categories): 1.1, 2.8, 2.4, 3.1, and 10.8% in hospital; 1.1, 3.0, 2.9, 3.5, and 10.2% at 30 days; and 1.6, 4.4, 4.7, 6.0, and 10.9% at 180 days. Multivariable predictors of 6-month mortality included age, heart rate and randomization, peak CK-MB ratio, time to CABG, prior angina, signs of congestive heart failure and randomization, three- and two-vessel coronary disease, enrolment infarction, ST-segment depression at enrolment, female sex, experimental treatment, and systolic blood pressure. CK-MB elevations after CABG are independently associated with increased risk of mortality in patients with NSTE ACS.