Abstract 12694: Use of Highly Sensitive Troponin T and N-Terminal Pro-Brain Natriuretic Peptide to Diagnose Acute Rejection in Pediatric Cardiac Transplant Recipients
Introduction: Biomarkers used in heart failure, including troponin T (cTnT) and brain natriuretic peptide (BNP), have been proposed to augment or replace endomyocardial biopsy (EMB) to diagnose acute transplant rejection, with inconsistent results. A new, precommercial assay for highly-sensitive cTnT (hs-cTnT, Elecsys analyzer, Roche Diagnostics) detects levels of cTnT 10-100 fold lower than standard assays, but has not been investigated in transplant patients. NT-proBNP, the more stable natriuretic peptide, has not been evaluated in pediatric transplant patients. The purpose of this study was to evaluate the association of levels of these biomarkers with acute rejection.
Methods: EDTA plasma was obtained at the time of EMB from pediatric transplant patients ≥ 1 year old. hs-cTnT and NT-proBNP were measured from stored samples and correlated with EMB results. Acute rejection (AR) was defined as an ISHLT biopsy score of Grade ≥ 2R.
Results: Fifty-three blood samples were obtained from 42 transplant patients. Seven episodes of AR occurred in 6 patients. Patients with vs without AR had higher hs-cTnT (median [IQR] 53 [9, 121] vs 7 [4,14] pg/mL, p<0.01) and NT-proBNP (median [IQR] 1708 [280, 16,975] vs 333 [154, 632] pg/mL, p<0.01). The AUROC for diagnosis of AR was 0.81 for hs-cTnT and 0.82 for NT-proBNP. Following successful treatment of AR in 5 patients, documented by improvement of ISHLT score to < 2R, hs-cTnTconsistently fell to the normal range (≤14pg/mL) (figure). NT-proBNP levels did not fall significantly with treatment.
Conclusion: In this pilot study, the first to evaluate hs-cTnT in pediatric heart transplant patients, we found marked elevation of hs-cTnT and NT-proBNP among children with acute rejection. Moreover, reduction in hs-cTnT levels after treatment paralleled improvement in EMB results. If these findings are confirmed in larger prospective studies, monitoring with serial measurements of hs-cTnT and NT-proBNP may obviate frequent, routine EMB.
- © 2010 by American Heart Association, Inc.