Prognostic importance of creatine kinase and creatine kinase-MB after primary percutaneous coronary intervention for ST-elevation myocardial infarction.

BACKGROUND: Although the prognostic significance of creatine kinase (CK) and creatine kinase-MB (CK-MB) after myocardial infarction has been established after thrombolysis or no reperfusion therapy, there is limited evidence of the prognostic importance after primary percutaneous coronary intervention (PCI).
METHODS: In this prospective, observational study, individual data from all patients who survived at least 2 days after primary PCI between 1991 and 2004 in our hospital were recorded. The association between enzymatic infarct size (examined by peak CK and peak CK-MB levels, each divided into tertiles) and both left ventricular ejection fraction (LVEF) and 1-year mortality was evaluated.
RESULTS: In the study group of 4670 patients, mean peak CK was 2327 U/L (SD 2008) and mean peak CK-MB was 244 U/L (SD 208). Both increased CK and CK-MB were associated with a lower LVEF. A total of 252 patients (5.4%) died between 2 days and 1 year after admission. Both peak CK and peak CK-MB were higher in those who died. Particularly, patients in the highest tertile of either peak CK or peak CK-MB had increased mortality, whereas the differences between the lower tertiles were not significant. In 2738 patients, after multivariable analysis including LVEF, the hazard ratio for 1-year mortality in patients in the highest CK tertile was 2.28 (95% CI 1.32-3.91) and for CK-MB, 1.91 (95% CI 1.11-3.26), compared to those in the other tertiles.
CONCLUSIONS: According to this large-scale study, peak CK and peak CK-MB are comparable independent predictors of LV function and 1-year mortality in patients after primary PCI.