title: Clinical and functional correlates of early microvascular dysfunction after heart transplantation.
abstract: BACKGROUND
  Microvascular dysfunction is emerging as a strong predictor of outcome in heart transplant recipients. At this time, the determinants and consequences of early microvascular dysfunction are not well established. The objective of the study was to determine the risk factors and functional correlates associated with early microvascular dysfunction in heart transplant recipients.
  
  
  RESULTS
  Sixty-three heart transplant recipients who had coronary physiology assessment, right heart catheterization, and echocardiography performed at the time of their first annual evaluation were included in the study. Microvascular dysfunction was assessed using the recently described index of microcirculatory resistance. The presence of microvascular dysfunction, predefined by an index of microcirculatory resistance >20, was observed in 46% of patients at 1 year. A history of acute rejection and undersized donor hearts were associated with microvascular dysfunction at 1 year, with odds ratio of 4.0 (1.3-12.8) and 3.6 (1.2-11.1), respectively. Patients with microvascular dysfunction had lower cardiac index (3.1±0.7 versus 3.5±0.7 L/min per m(2); P=0.02) and mild graft dysfunction measured by echocardiography-derived left and right myocardial performance indices ([0.54±0.09 versus 0.43±0.09; P<0.01] and [0.47±0.14 versus 0.32±0.05; P<0.01], respectively). Microvascular dysfunction was also associated with a higher likelihood of death, graft failure, or allograft vasculopathy at 5 years after transplant (hazard ratio, 2.52 [95% CI, 1.04-5.91]).
  
  
  CONCLUSIONS
  A history of acute rejection during the first year and smaller donor hearts were identified as risk factors for early microvascular dysfunction. Microvascular dysfunction assessed using index of microcirculatory resistances at 1 year was also associated with worse graft function and possibly worse clinical outcomes.
authors.affiliation: Department of Medicine, Stanford University, Stanford, CA, USA. fhaddad@stanford.edu
authors.forename: François
authors.initials: F
authors.lastname: Haddad
authors.forename: Prateeti
authors.initials: P
authors.lastname: Khazanie
authors.forename: Tobias
authors.initials: T
authors.lastname: Deuse
authors.forename: Dana
authors.initials: D
authors.lastname: Weisshaar
authors.forename: Jessica
authors.initials: J
authors.lastname: Zhou
authors.forename: Chang Wook
authors.initials: CW
authors.lastname: Nam
authors.forename: Thu A
authors.initials: TA
authors.lastname: Vu
authors.forename: Fatemeh A
authors.initials: FA
authors.lastname: Gomari
authors.forename: Mehdi
authors.initials: M
authors.lastname: Skhiri
authors.forename: Ana
authors.initials: A
authors.lastname: Simos
authors.forename: Ingela
authors.initials: I
authors.lastname: Schnittger
authors.forename: Bojan
authors.initials: B
authors.lastname: Vrotvec
authors.forename: Sharon A
authors.initials: SA
authors.lastname: Hunt
authors.forename: William F
authors.initials: WF
authors.lastname: Fearon
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004452:Echocardiography; D005260:Female; D006084:Graft Rejection / Q000453:epidemiology* / Q000503:physiopathology; D016027:Heart Transplantation / Q000502:physiology*; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D055806:Microvessels / Q000503:physiopathology*; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors