title: Cardiac allograft hypertrophy is associated with impaired exercise tolerance after heart transplantation.
abstract: BACKGROUND
  Exercise performance, an important aspect of quality of life, remains limited after heart transplantation (HTx). This study examines the effect of cardiac allograft remodeling on functional capacity after HTx.
  
  
  METHODS
  The total cohort of 117 HTx recipients, based on echocardiographic determination of left ventricle mass and relative wall thickness at 1 year after HTx, was divided into 3 groups: (1) NG, normal geometry; (2) CR, concentric remodeling; and (3) CH, concentric hypertrophy. Cardiopulmonary exercise testing was performed 5.03 ± 3.08 years after HTx in all patients. Patients with acute rejection or significant graft vasculopathy were excluded.
  
  
  RESULTS
  At 1 year post-HTx, 30% of patients had CH, 55% had CR and 15% had NG. Exercise tolerance, measured by maximum achieved metabolic equivalents (4.62 ± 1.44 vs 5.52 ± 0.96 kcal/kg/h), normalized peak Vo(2) (52 ± 14% vs 63 ± 12%) and Ve/Vco(2) (41 ± 17 vs 34 ± 6), was impaired in the CH group compared with the NG group. A peak Vo(2) ≤14 ml/kg/min was found in 6%, 22% and 48% of patients in the NG, CR and CH groups, respectively (p = 0.01). The CH pattern was associated with a 7.4-fold increase in relative risk for a peak Vo(2) ≤14 ml/kg/min compared with NG patients (95% confidence interval 1.1 to 51.9, p = 0.001). After multivariate analysis, a 1-year CH pattern was independently associated with a reduced normalized peak Vo(2) (p = 0.018) and an elevated Ve/Vco(2) (p = 0.035).
  
  
  CONCLUSIONS
  The presence of CH at 1 year after HTx is independently associated with decreased normalized peak Vo(2) and increased ventilatory response in stable heart transplant recipients. The identification of CH, a potentially reversible mechanism of impairment in exercise capacity after HTx, may have major clinical implications.
authors.affiliation: Division of Cardiology, University of Nebraska Medical Center, Omaha, Nebraska, USA.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Raichlin
authors.forename: Malik A
authors.initials: MA
authors.lastname: Al-Omari
authors.forename: Courtney L
authors.initials: CL
authors.lastname: Hayes
authors.forename: Brooks S
authors.initials: BS
authors.lastname: Edwards
authors.forename: Robert P
authors.initials: RP
authors.lastname: Frantz
authors.forename: Barry A
authors.initials: BA
authors.lastname: Boilson
authors.forename: Alfredo L
authors.initials: AL
authors.lastname: Clavell
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Rodeheffer
authors.forename: John A
authors.initials: JA
authors.lastname: Schirger
authors.forename: Sudhir S
authors.initials: SS
authors.lastname: Kushwaha
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Allison
authors.forename: Naveen L
authors.initials: NL
authors.lastname: Pereira
mesh_terms: D000328:Adult; D006332:Cardiomegaly / Q000503:physiopathology*; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D016027:Heart Transplantation / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010101:Oxygen Consumption; D011184:Postoperative Period; D011788:Quality of Life; D013318:Stroke Volume / Q000502:physiology; D014184:Transplantation, Homologous; D020257:Ventricular Remodeling / Q000502:physiology*