title: Sustained elevated concentrations of cardiac troponin T during acute allograft rejection after heart transplantation in children.
abstract: BACKGROUND
  The diagnosis of acute rejection after heart transplantation is made on the basis of endomyocardial biopsy. In children, where the method may be associated with complications, a noninvasive alternative would be desirable. We evaluated the myocardial damage marker cardiac troponin T (cTnT) as a marker of rejection in children who have undergone heart transplantation.
  
  
  METHODS
  Peripheral venous blood was collected in 124 endomyocardial biopsies in 14 children who had undergone heart transplantation (1-20 years of age). Serum levels of cTnT were compared with histologic rejection according to the International Society of Heart and Lung Transplantation (ISHLT) (grades 0-4).
  
  
  RESULTS
  Seven children experienced nine episodes of acute rejection. During rejection, cTnT increased from 0.05+/-0.07 (mean+/-SD) microg/L to 0.26+/-0.27 microg/L and remained elevated 7 and 30 days thereafter (0.10+/-0.11 and 0.36+/-0.38 microg/L, respectively) before returning to normal after 50 to 430 days. In surveillance biopsies, cTnT displayed considerable variation at all rejection grades: ISHLT grade 0, median 0.03 microg/L (range 0.01-2.04 microg/L); ISHLT grade 1, median 0.06 microg/L (range 0.01-0.67 microg/L); ISHLT grade 2, median 0.10 microg/L (range 0.01-1.42 microg/L); and ISHLT grade 3, median 0.17 microg/L (range 0.01-0.93 microg/L). A receiver operating characteristics analysis for cTnT versus rejection grade revealed an area under the curve of 0.69, indicating a moderate predictive value for cTnT. However, a cutoff of 0.015 microg/L yielded a specificity of only 36%, with a sensitivity of 89%, whereas a cutoff of 0.1 microg/L resulted in sensitivity and specificity of 53% and 77%, respectively.
  
  
  CONCLUSIONS
  Cardiac troponin T increased and remained elevated for at least 1 month during acute rejection. The diagnostic power of a single cTnT measurement was not sufficient to replace endomyocardial biopsy.
authors.affiliation: Department of Pediatrics, Division of Cardiology, The Queen Silvia Children's Hospital, SU/Ostra, SE-416 85 Göteborg, Sweden. hakan.wahlander@medfak.gu.se
authors.forename: Håkan
authors.initials: H
authors.lastname: Wåhlander
authors.forename: Christer
authors.initials: C
authors.lastname: Kjellström
authors.forename: Daniel
authors.initials: D
authors.lastname: Holmgren
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D015415:Biomarkers; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D005260:Female; D006084:Graft Rejection / Q000097:blood* / Q000473:pathology*; D016027:Heart Transplantation; D006801:Humans; D007223:Infant; D007668:Kidney / Q000502:physiology; D008297:Male; D009206:Myocardium / Q000473:pathology; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014184:Transplantation, Homologous; D020107:Troponin T / Q000097:blood*
chemical_list: D015415:Biomarkers; D020107:Troponin T