Prognostic significance of creatine kinase-MB elevation after percutaneous coronary intervention in patients with chronic renal dysfunction

Background: Multiple studies have demonstrated a relationship between creatine kinase-MB (CK-MB) elevation after percutaneous coronary intervention (PCI) and increased late mortality within the general population. Because CK-MB is frequently elevated in renal disease even in the absence of myocardial injury, the clinical significance of CK-MB elevation after PCI in patients with renal insufficiency has been questioned. Methods: We sought to examine the association between elevated CK-MB after PCI and late mortality in 190 consecutive patients with chronic renal insufficiency (serum creatinine ≥2.0 mg/dL) undergoing PCI at the Cleveland Clinic between January 1997 and March 2000. Of the total group, 20 patients undergoing PCI for acute myocardial infarction, cardiogenic shock, or both were excluded. Follow-up was 99.4% complete at a mean duration of 24.8 ± 11.2 months (range 5-43 months). Results: CK-MB elevation above the upper limit of normal after intervention was detected in 33 patients (19.4%). Baseline characteristics were not significantly different between the CK-MB elevation group and the normal CK-MB group. Late mortality, however, was significantly higher among patients with postprocedural CK-MB elevation (36.4% vs 17.5%, P = .017). Cox proportional hazard model revealed CK-MB elevation as an independent predictor of late mortality (hazard ratio 2.44, 95% CI 1.14-5.24, P = .02), in addition to New York Heart Association class (hazard ratio 1.35, 95% CI 1.05-1.73, P = .02). Conclusions: This analysis of patients with chronic renal insufficiency undergoing PCI suggests that postprocedural CK-MB elevation is an independent predictor of late mortality even in the presence of renal dysfunction.