title: Multiparametric cardiovascular magnetic resonance surveillance of acute cardiac allograft rejection and characterisation of transplantation-associated myocardial injury: a pilot study.
abstract: BACKGROUND
  Serial surveillance endomyocardial biopsies are performed in patients who have recently undergone heart transplantation in order to detect acute cardiac allograft rejection (ACAR) before symptoms occur, however the biopsy process is associated with a number of limitations. This study aimed to prospectively and longitudinally evaluate the performance of multiparametric cardiovascular magnetic resonance (CMR) for detecting and monitoring ACAR in the early phase post-transplant, and characterize graft recovery following transplantation.
  
  
  METHODS
  All patients receiving a heart transplant at a single UK centre over a period of 25 months were approached within one month of transplantation. Multiparametric CMR was prospectively performed on the same day as biopsy on four separate occasions (6 weeks, 10 weeks, 15 weeks and 20 weeks post-transplant). CMR included assessment of global and regional ventricular function, myocardial tissue characterization (T1 mapping, T2 mapping, extracellular volume, LGE) and pixel-wise absolute myocardial blood flow quantification. CMR parameters were compared with biopsy findings. As is standard, grade 2R or higher ACAR was considered significant.
  
  
  RESULTS
  88 CMR-matched biopsies were performed in 22 patients. Eight (9%) biopsies in 5 patients demonstrated significant ACAR. Significant ACAR was associated with a reduction in circumferential strain (-12.7±2.5% vs. -13.7±3.6%, p=0.047) but there was considerable overlap between groups. Whilst trends were observed between ACAR and proposed CMR markers of oedema, particularly after adjusting for primary graft dysfunction, differences were not significant. Significant improvements were seen in markers of graft structure and contractility, oedema and microvascular function over the period studied, although few parameters normalised.
  
  
  CONCLUSIONS
  This study provides novel insight into the myocardial injury associated with transplantation, and its recovery, however multiparametric CMR was not able to accurately detect ACAR during the early phase post-transplantation.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Miller
authors.forename: Josephine H
authors.initials: JH
authors.lastname: Naish
authors.forename: Steven M
authors.initials: SM
authors.lastname: Shaw
authors.forename: Nizar
authors.initials: N
authors.lastname: Yonan
authors.forename: Simon G
authors.initials: SG
authors.lastname: Williams
authors.forename: David
authors.initials: D
authors.lastname: Clark
authors.forename: Paul W
authors.initials: PW
authors.lastname: Bishop
authors.forename: Mark P
authors.initials: MP
authors.lastname: Ainslie
authors.forename: Alex
authors.initials: A
authors.lastname: Borg
authors.forename: Glyn
authors.initials: G
authors.lastname: Coutts
authors.forename: Geoffrey J M
authors.initials: GJ
authors.lastname: Parker
authors.forename: Simon G
authors.initials: SG
authors.lastname: Ray
authors.forename: Matthias
authors.initials: M
authors.lastname: Schmitt
mesh_terms: D000208:Acute Disease; D000328:Adult; D064591:Allografts; D001706:Biopsy; D003326:Coronary Circulation; D042241:Early Diagnosis; D004739:England; D005260:Female; D006084:Graft Rejection / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D016027:Heart Transplantation / Q000009:adverse effects*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009206:Myocardium / Q000473:pathology*; D010865:Pilot Projects; D011237:Predictive Value of Tests; D011446:Prospective Studies; D020127:Recovery of Function; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left