title: Incremental shuttle walk test in the assessment of patients for heart transplantation.
abstract: OBJECTIVE
  To compare the incremental shuttle walk test (ISWT) with treadmill exercise testing (TT) derived measurement of peak oxygen consumption (peak VO(2)) in patients undergoing assessment for cardiac transplantation.
  
  
  METHODS
  Prospective comparison. All investigations occurred during a single period of admission for transplant assessment.
  
  
  METHODS
  Single UK cardiothoracic transplantation unit.
  
  
  METHODS
  25 patients recruited (21 men). Mean age was 53 years.
  
  
  METHODS
  Patients underwent two TT of peak VO(2) using the modified Naughton protocol and three (one practice) ISWT. Investigations were performed on consecutive days.
  
  
  METHODS
  Main outcome measures were repeatability of TT and ISWT assessments; relation between peak VO(2) and distance walked in the ISWT; and receiver operating characteristic (ROC) analysis to establish a distance walked in the ISWT that predicted which patients would have a peak VO(2) greater than 14 ml/min/kg.
  
  
  RESULTS
  Both the ISWT and the TT were highly reproducible. Following the first practice walk, mean (SD) ISWT distances were 400.0 (146) m (ISWT2) and 401.3 (129) m (ISWT3), r = 0.90, p < 0.0001. Mean peak VO(2) by TT was 15.2 (4.4) ml/kg/min (TT1) and 15.0 (4.4) ml/kg/min (TT2), r = 0.83, p < 0.0001. The results revealed a strong correlation between distance covered in the ISWT and peak VO(2) obtained during TT (r = 0.73, p = 0.0001). ROC analysis showed that a distance walked of 450 m allowed the selection of patients with a peak VO(2) of over 14 ml/min/kg.
  
  
  CONCLUSIONS
  This work confirms the utility of the ISWT in the assessment of exercise capacity in patients with severe heart failure undergoing assessment for cardiac transplantation. ISWT may provide a widely applicable surrogate measure for peak VO(2) estimation in this population. Shuttle distance walked may therefore allow the convenient, serial assessment of patients with heart failure before referral for transplantation.
authors.affiliation: Heart and Lung Transplantation Unit, Department of Cardiothoracic Surgery, Queen Elizabeth Hospital, University Hospital NHS Trust, Birmingham B15 2TH, UK.
authors.forename: M E
authors.initials: ME
authors.lastname: Lewis
authors.forename: C
authors.initials: C
authors.lastname: Newall
authors.forename: J N
authors.initials: JN
authors.lastname: Townend
authors.forename: S L
authors.initials: SL
authors.lastname: Hill
authors.forename: R S
authors.initials: RS
authors.lastname: Bonser
mesh_terms: D005080:Exercise Test / Q000379:methods*; D005260:Female; D006331:Heart Diseases / Q000503:physiopathology / Q000601:surgery; D016027:Heart Transplantation / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D018579:Patient Selection; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016138:Walking / Q000502:physiology