A study comparing the incidence and predictors of creatine kinase MB and troponin T release after coronary angioplasty. Does Clopidogrel preloading reduce myocardial necrosis following elective percutaneous coronary intervention?

BACKGROUND

To investigate the incidence and associated factors for enzyme release following percutaneous coronary intervention comparing assessment with creatine kinase MB (CK-MB) and troponin T (TnT).

METHOD

TnT and CK-MB were measured post procedure in a consecutive series of 933 patients undergoing elective percutaneous coronary intervention between 1/4/2003 and 1/5/2004 at a single regional cardiac centre.

RESULTS

CK-MB level significantly correlated to TnT levels (R=0.747, p<0.001) and a CK-MB level of above 3 times the upper limit of the local reference range (>3 x ULN) was predicted with 95% sensitivity (48% specificity) at a TnT level of 0.11. Multivariate predictors of >3 x ULN CK-MB release for uncomplicated percutaneous coronary intervention (n=898) were multi-vessel angioplasty (OR=2.51, 95% CI=1.57 to 4.01; p<0.001), saphenous venous graft angioplasty (OR=5.5, 95% CI=1.94 to 13.00; p=0.005) and lack of Clopidogrel preloading (OR=2.02, 95% CI=1.30 to 4.38; p=0.027).

CONCLUSIONS

TnT was found to be a sensitive although not a highly specific marker of CK-MB release. In this study a TnT level above a threshold of 0.11 would identify 95% of the prognostically important 3-fold CK-MB releases. Replacing the >3 x ULN CK-MB threshold with a TnT level of 0.1 ng/l following percutaneous coronary intervention would increase the apparent rate of myocardial infarction from 11% to 20%. Lack of Clopidogrel preloading was independently associated with a >3 x ULN CK-MB release following uncomplicated elective percutaneous coronary intervention.