Prognostic implication of creatine kinase elevation following elective coronary artery interventions

Objective.-To determine the prognostic significance of creatine kinase (CK) elevation following elective percutaneous transluminal coronary angioplasty (PTCA). Design.-Retrospective cohort study, Setting.-Tertiary care referral center. Subjects.-A total of 253 consecutive patients with total CK and CK-MB fraction (CK-MB) elevation (case patients) and 120 patients without CK elevation (controls). Control patients had undergone interventions during the same month and year using the same devices. Main Outcome Measures.-In-hospital and late cardiac mortality, subsequent myocardial infarction, and the combined end point of cardiac mortality or myocardial infarction. Results.-Patient groups were similar with respect to age, sex, extent of coronary artery disease, left ventricular function, number of lesions treated by PTCA, and mean duration of follow-up (>3.5 years). Cardiac mortality was significantly greater (P=.02) for patients with CK elevation after PTCA, When patients were categorized according to peak CK elevation, cardiac mortality differed significantly among patient groups (P=.007), with increased cardiac mortality observed for patients with high (>3,0 times normal) and intermediate (1,5 to 3.0 times normal) CK elevations. In multivariate analyses, higher peak CK and lower ejection fraction were the most important predictors of increased cardiac mortality (both, P<.001); the relative risk for cardiac mortality was 1.05 (95% confidence interval, 1.03-1.08) per 100-U/L increment increase in CK. Conclusions.-Creatine kinase elevation following elective PTCA is associated with increased late cardiac mortality. This increase in cardiac mortality is independent of clinical variables, severity of heart disease, coronary artery lesion characteristics, interventional devices, and procedural outcomes. Even patients with lesser degrees of CK elevation are at significantly increased risk for late cardiac death.