Background: The significance of mild elevations in cardiac enzymes after an elective percutaneous coronary intervention (PCI) still remains controversial. We evaluated the significance of creatine phosphokinase level (CPK) elevations in a large cohort of patients who had undergone an elective PCI before the IIb/IIIa receptor antagonist era.
Methods: All patients enrolled in the Emory databank from 1981 to 1996 who had an elective PCI were evaluated. We identified 15,637 patients who met our inclusion and exclusion criteria. Patients were divided into 4 groups on the basis of the magnitude of the CPK elevation noted in the post-PCI period: group I (CPK <250 mg/dL, n = 14,512); group II (CPK 250-500 mg/dL, n = 715); group III (CPK 500-750 mg/dL, n = 164); and group IV (CPK >750 mg/dL, n = 246).
Results: CPK elevations were associated with a significant increase in the periprocedure angiographic complications. Angiographic complication rates were 14.6%, 30.5%, 40.2%, and 43.5% in groups I, II, III, and IV, respectively (P <.001). Long-term survival also correlated inversely with the magnitude of CPK elevations. The 10-year survival rates were 73%, 71%, 69%, and 55% in groups I, II, III, and IV, respectively (P <.0001). After multivariate analysis to correct for clinical factors, a CPK elevation of at least 3-times normal (group IV) was found to be an independent predictor of diminished 30-day and long-term survival (hazard ratio 1.84, 95% CI 1.41-2.41, P <.0001). Elevations in CPK <3-times normal (groups II and III) were not independently predictive of poor long-term survival.
Conclusion: A CPK level >3-times normal after an elective PCI is a strong independent predictor of poor long-term prognosis.