Cardiac troponin T and I and creatine kinase-MB as markers of myocardial injury and predictors of outcome following percutaneous coronary intervention

This study was performed to determine the most sensitive biochemical marker for the detection of cardiac myocyte damage potentially sustained during percutaneous coronary intervention (PCI) and to assess whether such a marker can be used to identify patients at increased risk of poor subsequent clinical outcome.We studied 109 consecutive patients presenting with clinical stable and unstable angina and undergoing PCI at our institution. Blood was sampled for creatine kinase-MB (CK-MB), cardiac Troponin T (cTnT) and I (cTnI) immediately before and at 6, 14 and 24 h post-PCI. Five patients with raised cardiac markers pre-PCI were excluded from further analysis. The occurrence of major adverse cardiac events (MACE) was documented in-hospital, at 30 days and at long-term clinical follow up of up to 20 months. MACE occurred in 26/109 (24%) patients: death=1, QWMI=4, NQWMI=5, repeat PCI=16 (nine target vessel revascularisations and seven de-novo lesions), CABG=5. cTnI had the highest detection rate for myocardial damage, with 58 cTnI-positive patients, 38 cTnT-positive patients and 28 CK-MB-positive patients in the 24 h following PCI (Pearson's Chi square test, P<0.01). The type of interventional strategy per se was not significantly associated with post-procedural cardiac marker concentrations (Kruskal-Wallis ANOVA, P>0.05). There was a significant association between post-procedural cardiac marker concentrations of CK-MB, cTnT and cTnI and the occurrence of procedural angiographic complications (P=0.0003, 0.0002, 0.001, respectively). All three markers, at each sampling time point between 6 and 24 h post-PCI, showed a significant predictive relationship with MACE in-hospital and at long-term follow up (ROC curve AUC analysis, P<0.05). All three markers provided equally predictive information at each of the three post-procedural sampling time points between 6 and 24 h following PCI. All levels of cardiac marker elevation above the clinically discriminant cut-off values were significantly predictive of outcome at long-term follow up.cTnI proved to be the most sensitive marker in detecting myocardial necrosis following PCI. CK-MB, cTnT and cTnI all provided similarly reliable prognostic information, with cTnT and cTnI being marginally superior in predicting MACE at follow up.