title: Exercise capacity is the strongest predictor of mortality in patients with peripheral arterial disease.
abstract: OBJECTIVE
  The objective of this study was to assess the predictive value of clinical and exercise test variables in patients with peripheral arterial disease (PAD).
  
  
  METHODS
  A customized symptom-limited ramp treadmill protocol was used to assess 725 PAD patients referred for exercise testing at the Palo Alto Veterans Hospital between 1997 and 2011. Detailed clinical and exercise test data were collected at baseline, and patients were followed up for a mean of 11.3 ± 6.3 years.
  
  
  RESULTS
  During follow-up, there were 364 deaths. Baseline exercise capacity was 7.0 ± 2.6 metabolic equivalents (METs) among survivors and 5.5 ± 2.4 METs in those who died (P < .001). Although several physiologic parameters differed between survivors and nonsurvivors, age-adjusted Cox regression revealed that exercise capacity was the strongest independent predictor of death. Each additional MET achieved was associated with age-adjusted 18% and 20% reductions in all-cause and cardiovascular mortality, respectively (P < .001 for both). This variable surpassed all classical risk factors (including smoking and history of congestive heart failure) and all measured exercise test responses (including symptoms and electrocardiograph abnormalities).
  
  
  CONCLUSIONS
  Among PAD patients, reduced exercise capacity is the most powerful harbinger of long-term mortality. This factor has predictive power beyond traditional risk factors and confirms the critical importance of fitness in this cohort.
authors.affiliation: Division of Vascular Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA. nleeper@stanford.edu
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Leeper
authors.forename: Jonathan
authors.initials: J
authors.lastname: Myers
authors.forename: Margaret
authors.initials: M
authors.lastname: Zhou
authors.forename: Kevin T
authors.initials: KT
authors.lastname: Nead
authors.forename: Arshiya
authors.initials: A
authors.lastname: Syed
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kojima
authors.forename: Roxanne Diaz
authors.initials: RD
authors.lastname: Caceres
authors.forename: John P
authors.initials: JP
authors.lastname: Cooke
mesh_terms: D000368:Aged; D002140:California; D016009:Chi-Square Distribution; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D005500:Follow-Up Studies; D006787:Hospitals, Veterans; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D058729:Peripheral Arterial Disease / Q000175:diagnosis* / Q000401:mortality* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors