Prognostic implication of cardiac troponin T increase following stent implantation

Objective: To identify the incidence and clinical significance of myocardial injury following elective stent implantation. Design: Prospective clinical study with 278 consecutive patients undergoing stenting of de novo coronary or saphenous vein graft lesions. Incidence of periprocedural myocardial injury was assessed by analysis of 12 lead ECG, creatine kinase (CK; upper limit of normal (ULN) 70 IU/I for women, 80 IU/I for men), and cardiac troponin T (cTnT; point of care test; threshold 0.1 ng/ml) before and 6, 12, and 24 hours after the intervention. Major adverse cardiac events (MACE: acute myocardial infarction, bypass surgery, and cardiac death) were recorded during clinical follow up (mean (SD) 7.8 (5.3) months). Results: Following elective stenting, the rate of a positive cTnT status was 17.3%, the rate of CK increase of 1-3x ULN 14.7%, the rate of CK increase of > 3x ULN 1.4%, and the rate of Q wave myocardial infarction 0.4%. Cardiac mortality during follow up was higher in patients with postprocedurally increased CK (7.1% v 1.3%, p = 0.01, log rank) and cTnT (9.1% v 0.9%, p < 0.001, log rank). In addition, postprocedurally increased cTnT was associated with a higher overall incidence of MACE (13.1% v 4.0%, p < 0.01, log rank) and was identified as an independent factor for MACE during follow up (hazard ratio 3.27, 95% confidence interval 1.14 to 9.41, p = 0.028). Conclusions: Following elective stent implantation, a positive cTnT status identified patients at risk of a worse long term outcome. Treatment strategies have to be developed that lead to prognostic improvement by reducing periprocedural myocardial injury.