Trajectories of postoperative serum troponin concentrations following pediatric heart transplantation

Background Troponin is a biomarker of myocardial injury and death but has not been well studied after pediatric heart transplants. The objective of this analysis is to describe the distribution and clinical determinants of serum troponin measured in the first week after pediatric heart transplantation. Methods We included all patients who underwent heart transplantation at Seattle Children's Hospital between 2012 and 2016. Serum Troponin-I (TnI) was measured daily in the first week after transplant. We described the distribution of serum TnI, and examined the relationship between peak TnI with known pre- peri-operative risk factors for myocardial injury including etiology of heart failure, ischemia time, and donor to recipient characteristics. Logistic regression models were used to test the association between peak TnI with incidence of death or rejection and formation of donor-specific antibodies (DSA) within 1 year. Adjusted models included age, HF etiology, crossmatch status, and panel reactive antibodies. Results During the study period, 86 transplants were performed on 83 unique individuals. Serum TnI peaked at a median of 0.9 days after transplantation. In adjusted models, higher peak TnI was associated with death and/or rejection within 1-year post-transplant (odds ratio [95% confidence interval]: 1.10 [1.02, 1.19]). Peak TnI was not associated with de-novo DSA formation in adjusted models (OR [95%CI]: 1.01 [0.94, 1.09]). Post-transplant length of stay in the intensive care unit was positively correlated with peak TnI ( r = 0.36, p < 0.001). Conclusions This study describes serum TnI in the first week after pediatric heart transplant; a population for whom existing data are sparse. Our findings suggest TnI may have utility as a readily measurable biomarker of transplant-related myocardial injury. These results may inform future investigations of the prognostic significance of higher post-transplant TnI in future studies.