title: Myocardial Perfusion Reserve and Strain-Encoded CMR for Evaluation of Cardiac Allograft Microvasculopathy.
abstract: OBJECTIVE
  This study sought to evaluate myocardial perfusion reserve index (MPRI) and diastolic strain rate, both assessed by cardiac magnetic resonance (CMR) as a noninvasive tool for the detection of microvasculopathy.
  
  
  BACKGROUND
  Long-term survival of cardiac allograft recipients is limited primarily by cancer and cardiac allograft vasculopathy (CAV). Besides epicardial CAV, diagnosed by coronary angiography, stenotic microvasculopathy was found to be an additional independent risk factor for survival after heart transplantation.
  
  
  METHODS
  Sixty-three consecutive heart transplant recipients who underwent CMR, coronary angiography, and myocardial biopsy were enrolled. Stenotic vasculopathy in microvessels was considered in myocardial biopsies by immunohistochemistry and CAV was graded during coronary angiography according to International Society of Heart and Lung Transplantation criteria. In addition, by CMR microvasculopathy was assessed by myocardial perfusion reserve during pharmacologic hyperemia with adenosine and strain-encoded magnetic resonance using a modified spatial modulation of magnetization tagging pulse sequence in all patients.
  
  
  RESULTS
  Decreasing MPRI and diastolic strain rates were observed in patients with decreasing microvessel luminal radius to wall thickness ratio and decreasing capillary density (r = 0.45 and r = 0.61 for MPRI and r = 0.50 and r = 0.38 for diastolic strain rate, respectively; p < 0.005 for all). Using multivariable analysis, both MPRI and diastolic strain rate were robust predictors of stenotic microvasculopathy, independent of age, organ age, and CAV by International Society of Heart and Lung Transplantation criteria (hazard ratio: 0.07, p = 0.006 for MPRI; hazard ratio: 0.91, p = 0.002 for diastolic strain rate). Patients without stenotic microvasculopathy in the presence of no or mild CAV (n = 36) exhibited significantly higher median survival free of events, compared with patients with stenotic microvasculopathy in the presence of no or mild CAV (n = 18; p = 0.04 by log rank).
  
  
  CONCLUSIONS
  CMR represents a valuable noninvasive diagnostic tool, which may be used for the early detection of transplant microvasculopathy before the manifestation of CAV during surveillance coronary angiographic procedures.
authors.affiliation: Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Erbel
authors.affiliation: Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Nodira
authors.initials: N
authors.lastname: Mukhammadaminova
authors.affiliation: Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Christian A
authors.initials: CA
authors.lastname: Gleissner
authors.affiliation: Myocardial Solutions, Inc., Morrisville, North Carolina.
authors.forename: Nael F
authors.initials: NF
authors.lastname: Osman
authors.affiliation: Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Nina P
authors.initials: NP
authors.lastname: Hofmann
authors.affiliation: Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Steuer
authors.affiliation: Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Mohammadreza
authors.initials: M
authors.lastname: Akhavanpoor
authors.affiliation: Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Wangler
authors.affiliation: Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Sultan
authors.initials: S
authors.lastname: Celik
authors.affiliation: Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Andreas O
authors.initials: AO
authors.lastname: Doesch
authors.affiliation: Institute of Psychology, University of Heidelberg, Heidelberg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Voss
authors.affiliation: Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Sebastian J
authors.initials: SJ
authors.lastname: Buss
authors.affiliation: Institute for Pathology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Schnabel
authors.affiliation: Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Hugo A
authors.initials: HA
authors.lastname: Katus
authors.affiliation: Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany. Electronic address: gkorosoglou@hotmail.com.
authors.forename: Grigorios
authors.initials: G
authors.lastname: Korosoglou
mesh_terms: D000241:Adenosine / Q000008:administration & dosage; D000328:Adult; D000368:Aged; D064591:Allografts; D001706:Biopsy; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D016027:Heart Transplantation / Q000009:adverse effects*; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D009200:Myocardial Contraction; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D013314:Stress, Mechanical; D016896:Treatment Outcome; D014665:Vasodilator Agents / Q000008:administration & dosage
chemical_list: D014665:Vasodilator Agents; D000241:Adenosine
keywords: capillary density; cardiac magnetic resonance; heart transplantation; microvasculopathy; microvessel lumen to wall thickness; myocardial perfusion reserve index; strain-encoded CMR