title: Response of the oxygen uptake efficiency slope to orthotopic heart transplantation: lack of correlation with changes in central hemodynamic parameters and resting lung function.
abstract: BACKGROUND
  Recently, a new linear measure of ventilatory response to exercise, the oxygen uptake efficiency slope (OUES), was proposed in the evaluation of heart failure patients. No data are available on the response of the OUES after orthotopic heart transplantation (HTx).
  
  
  METHODS
  Thirty patients who underwent HTx between 1999 and 2003 were included in the study. Data from maximal cardiopulmonary exercise test, resting pulmonary function and hemodynamic assessment were collected before the transplant at time of screening and 1 year after HTx.
  
  
  RESULTS
  During the first year after HTx, OUES and normalized OUES for body weight (OUES/kg) increased significantly from 15.6 +/- 4.9 to 19.7 +/- 4.8 (p < 0.05). Changes in OUES/kg were significantly correlated with changes in peak VO2, VAT and peak VE, and inversely to changes in peak VD/VT, but not to changes in VE/VCO2 slope (all p < 0.05). Changes in OUES or OUES/kg did not correlate with any changes in measures of resting lung volumes or capacities and measures of central hemodynamic function after HTx.
  
  
  CONCLUSIONS
  OUES improved significantly after HTx, but, similar to other exercise parameters, remained considerably impaired. The changes in OUES were highly correlated with the improvements in other exercise variables, but did not correlate with marked improvements in central hemodynamics or resting lung function.
authors.affiliation: Cardiovascular Center, Onze Lieve Vrouw Ziekenhuis, Aalst, Belgium. kine.van.laethem@telenet.be
authors.forename: Christophe
authors.initials: C
authors.lastname: Van Laethem
authors.forename: Marc
authors.initials: M
authors.lastname: Goethals
authors.forename: Sofie
authors.initials: S
authors.lastname: Verstreken
authors.forename: Maarten
authors.initials: M
authors.lastname: Walravens
authors.forename: Francis
authors.initials: F
authors.lastname: Wellens
authors.forename: Margot
authors.initials: M
authors.lastname: De Proft
authors.forename: Jozef
authors.initials: J
authors.lastname: Bartunek
authors.forename: Marc
authors.initials: M
authors.lastname: Vanderheyden
mesh_terms: D000328:Adult; D002320:Cardiovascular Physiological Phenomena; D005080:Exercise Test; D005260:Female; D016027:Heart Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D012143:Respiratory Physiological Phenomena; D012146:Rest