title: Prospective evaluation of the oxygen uptake efficiency slope as a submaximal predictor of peak oxygen uptake in aged patients with ischemic heart disease.
abstract: BACKGROUND
  The purpose of this study was to evaluate the oxygen uptake efficiency slope (OUES) as a predictor of peak oxygen consumption (VO2) in aged patients with coronary artery disease (CAD) and to compare its predictive value to that of ventilatory anaerobic threshold (VAT).
  
  
  METHODS
  A total of 160 aged (>60 years) patients with stable CAD performed a maximal cardiopulmonary exercise test. The equations were computed by using data of 85 randomly selected patients and were validated in the remaining 75 patients. Bland-Altman (BA) analysis was used to assess the agreement between measured and predicted peak VO2.
  
  
  RESULTS
  In the first 85 patients, peak VO2 correlated best with VAT and OUES per kilogram (P < .001). The linear regression to predict peak VO2 for OUES per kilogram was peak VO2 = 4.591 + 0.64 x OUES/kg (SEE = 2.61 mL kg(-1) min(-1)). The BA 95% limits of agreement were -29% and +30% of the predicted value. For VAT, the linear regression to predict peak VO2 was peak VO2 = 2.995 + 1.251 x VAT (SEE = 2.26 mL kg(-1) min(-1)). The BA 95% limits of agreement were -23% and +33% of the predicted value. Cross-tabulation analysis in 3 subgroups with different exercise capacities showed significant relationship between predicted and measured peak VO2 (all P < .001). OUES per kilogram showed the best measure of agreement with measured peak VO2, resulting in high sensitivity and specificity scores.
  
  
  CONCLUSIONS
  OUES is not able to acceptably predict peak VO2 in aged patients with CAD but is at least as performant as VAT in categorizing patients into subgroups with different exercise capacities. Therefore, the objectively measurable OUES is the preferred submaximal predictor of functional capacity in the assessment of aged patients with CAD.
authors.affiliation: Department of Cardiology, University Hospital Gent, Belgium.
authors.forename: Christophe
authors.initials: C
authors.lastname: Van Laethem
authors.forename: Nico
authors.initials: N
authors.lastname: Van de Veire
authors.forename: Johan
authors.initials: J
authors.lastname: De Sutter
authors.forename: Jozef
authors.initials: J
authors.lastname: Bartunek
authors.forename: Guy
authors.initials: G
authors.lastname: De Backer
authors.forename: Marc
authors.initials: M
authors.lastname: Goethals
authors.forename: Marc
authors.initials: M
authors.lastname: Vanderheyden
mesh_terms: D000166:Acridines; D000368:Aged; D002245:Carbon Dioxide / Q000378:metabolism; D005260:Female; D006801:Humans; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000503:physiopathology*; D010101:Oxygen Consumption; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015363:Quinolones; D012119:Respiration
chemical_list: D000166:Acridines; D015363:Quinolones; C069431:linear quinacridone; D002245:Carbon Dioxide