Myonecrosis following isolated coronary artery bypass grafting is common and associated with an increased risk of long-term mortality

Aims We sought to evaluate the risk of long-term mortality with respect to post-operative elevation of the isoenzyme CK-MB following first-time isolated coronary artery bypass grafting (CABG) surgery. Methods Patients undergoing first-time isolated CABG between September 1992 and December 2001, at the Mid America Heart Institute, were included in this registry analysis. A sole CK-MB measurement was obtained at an average of 15.2h following CABG. The main endpoint was long-term mortality. Results There were 3667 patients included in this registry. The mean follow up was 5.1 years. The event-free survival rate was 80%, 78% and 73%, for the normal, 1–3 and >3 times by ULN groups respectively; log-rank p=0.0058. The event-free survival for the four CK-MB groups was 80%, 78%, 75% and 72% for the normal, 1–3 times, >3–5, and >5 times ULN groups respectively, log-rank p=0.0078. The CK-MB elevation following CABG remained a significant predictor following multivariate adjustment. With a point estimate of 1.04, 95% confidence limits 1.009–1.062, p=0.007. Conclusion Elevation of the isoenzyme CK-MB is an important predictor of longterm mortality following coronary bypass grafting. These data support routine use of creatinine kinase measurement following bypass surgery to further delineate long-term risk.