Use of a Highly Sensitive Assay for Cardiac Troponin T as an Adjunct to Diagnose Acute Rejection after Cardiac Transplant

Objective: As a consequence to cardiomyocyte damage and inflammatory response, it may be possible that highly sensitive cardiac troponin T (hs-cTnT) and CRP- as well PCT-concentrations may correlate with the histologic degree of rejection in patients after heart transplant (htx). As former results regarding cTnT in this topic are inconsistent, we wanted to evaluate the new hs-cTnT as a potential adjunct to endomyocardial biopsy (EMB) in diagnosis of rejection after htx.

Methods: We measured hs-cTnT levels in heart transplant recipients on the first 5 postoperative days and with each biopsy. CRP, PCT and creatine kinase MB were also determined at the same times. The results of EMB were graded according the classification of the International Society of Heart and Lung Transplantation (ISHLT) of 2005. Rejection was defined as an ISHLT grade ≥ 2R.

Results: Between 10/2010 and 09/2015, a total of 55 patients underwent htx in our department. A total of 220 biopsies were performed with a mean follow-up of 1072 days (range:14–1838 days). We had 10 rejection episodes in which we could measure a moderate elevation of hs-cTnT levels (p = 0.05), whereas CRP increased significantly starting one day before EMB (p < 0.05). However, concentrations of CK-MB and PCT remained constantly low at the same times. TnT-levels decreased to baseline values immediately after successful treatment of rejection.

Conclusion: Cardiac TnT measured by the new highly sensitive assay increased in the presence of an acute rejection. In combination with CRP it may be a useful parameter to support the posttransplant management with regard to clinical and histological suspicion of rejection.