Cardiac-specific troponin I levels and risk of coronary artery disease and graft failure following heart transplantation

Context Previous studies have yielded conflicting data regarding whether a relationship exists between elevated cardiac troponin levels and acute allograft rejection in patients who have received heart transplants, Objective To determine whether cardiac troponin I levels after heart transplantation were associated with a procoagulant microvasculature and long-term allograft outcome. Design Prospective cohort study with a mean (SE) follow-up of 45.1 (2.5) months. Serum troponin I levels were measured 9.9 (0.2) times per patient during the first 12 months after heart transplantation. Setting Heart transplant center in the United States. Patients A total of 110 consecutive patients who received a heart transplant between 1989 and 1997 and survived at least 1 year after transplantation. Main Outcome Measures Histological and immunohistochemical biopsy findings, development of coronary artery disease (CAD), and graft failure in patients with vs without elevated serum cardiac troponin I levels. Results All recipients had elevated troponin I levels during the first month after transplantation. Troponin I levels remained persistently elevated during the first 12 months in 56 patients (51%) and became undetectable in 54 patients (49%). Persistently elevated troponin I levels were associated with increasing fibrin deposits in microvasculature and cardiomyocytes (P<.001). Patients with persistently elevated levels of troponin I had significantly increased risk for subsequent development of CAD (odds ratio [OR], 4.3, 95% confidence interval [CI], 1.8-10.1; P<.001) and graft failure (OR, 3.4; 95% CI, 1.2-9.7; P=.02), and also developed more severe CAD (OR, 4.2; 95% CI, 1.9-9.3; P<.001) and showed more disease progression (OR, 3.7; 95% CI, 1.3-10.4; P=.009). Conclusion In this study, elevated cardiac troponin I levels, which are considered to be a noninvasive surrogate marker of a procoagulant microvasculature, identified a subgroup of patients with high risk for developing CAD and graft failure after cardiac transplantation.