Association between CK-MB elevation after percutaneous or surgical revascularization and three-year mortality

Abstract

Objectives: The goal of this study was to assess the long-term impact of creatine kinase-MB isoform (CK-MB) elevation after percutaneous or surgical revascularization.

Background: The long-term impact of CK-MB elevation after coronary artery bypass grafting (CABG) is not as well characterized as that following percutaneous coronary intervention (PCI).

Methods: The three-year cumulative survival of consecutive patients who underwent their first percutaneous or surgical revascularization procedure between January 1, 1995 and August 31, 2000 and had CK-MB determination was assessed using the Social Security Death Index.

Results: The 3,812 patients undergoing CABG had a less favorable coronary risk profile than the 3,573 patients undergoing PCI. The incidence of CK-MB elevation above normal range was 90% and 38% for the CABG and PCI groups (p < 0.001). In 6% and 5%, respectively, the elevation surpassed 10x the upper limit of normal (ULN). At an average follow-up of three years, there were 712 deaths, 83 of which occurred within 30 days of procedure. The cumulative survival was 92% and 90% for CABG and PCI, respectively (p = 0.003). Chronic renal insufficiency (adjusted hazard ratio [HR] 3.8, [95% confidence interval 3.1 to 4.6]), age (HR 1.5 per decade [1.3 to 1.6]), ejection fraction <40% (HR 1.3 [1.1 to 1.5] and PCI (HR 1.6 [1.3 to 1.9]) were the main predictors of increased mortality. Creatine kinase-MB isoform elevation only above 10 x ULN was independently predictive of mortality in the CABG (HR 1.3 [1.1 to 1.5]) and PCI (HR 1.1 [1.0 to 1.2]) groups, p < 0.001.

Conclusions: Creatine kinase MB isoform elevation after revascularization is very common, particularly in CABG patients. When extensive, it is independently correlated with increased mortality over a three-year period. Identification and aggressive management of patients with high levels of CK-MB after revascularization may improve their outcome.