title: Outcome associations of carotid-femoral pulse wave velocity vary with different measurement methods.
abstract: BACKGROUND
  The impact of various methods of travel distance estimation on the prognostic value of pulse wave velocity (PWV) and on the adequacy of cut-offs has never been addressed within a single population of hypertensive patients.
  
  
  METHODS
  Four carotid-femoral PWVs were calculated from four different travel distances (Direct, Real, Subtracted, and Estimated) divided by the same travel time in 426 hypertensives (mean age 51.2 ± 13.8 years, mean systolic blood pressure 155.6 ± 21.1 mm Hg). The incidence of death from any cause and major cardiovascular events was studied. PWV predictive accuracies were determined using C-index analysis. Hazard ratios (HRs) associated with specific values of PWV were determined with Cox model analyses using cubic splines.
  
  
  RESULTS
  Mean PWV ranged from 8.3 ± 2.3 m/s for the Subtracted one to 11.6 ± 3.0 m/s for the Direct one (P < 0.001). When included as continuous variables in a Cox model, the four PWVs were significantly associated with outcome (all P < 0.001), and had similar C-index (0.608-0.617). In multivariable analysis, the HR calculated for a Direct PWV of 12 m/s was neutral (HR = 1.02). In contrast, the same analysis provided HR ranging from 1.79 to 2.90 with the other PWVs.
  
  
  CONCLUSIONS
  Different travel distances markedly impact PWV values and prognostic cut-offs. PWV cut-offs should consequently be ascertained jointly with the method of measurement used. There is an urgent need for standardization of PWV assessment before implementing this parameter in the routine management of hypertensives.
authors.affiliation: Department of Cardiology, ESH Hypertension Excellence Center, Croix-Rousse Hospital, Hospices Civils de Lyon, France. nicolas_girerd@yahoo.com
authors.forename: Nicolas
authors.initials: N
authors.lastname: Girerd
authors.forename: Liliana
authors.initials: L
authors.lastname: Legedz
authors.forename: Vinciane
authors.initials: V
authors.lastname: Paget
authors.forename: Muriel
authors.initials: M
authors.lastname: Rabilloud
authors.forename: Hugues
authors.initials: H
authors.lastname: Milon
authors.forename: Giampiero
authors.initials: G
authors.lastname: Bricca
authors.forename: Pierre
authors.initials: P
authors.lastname: Lantelme
mesh_terms: D000328:Adult; D000368:Aged; D062186:Arterial Pressure; D002339:Carotid Arteries / Q000503:physiopathology*; D002423:Cause of Death; D005260:Female; D005263:Femoral Artery / Q000503:physiopathology*; D006801:Humans; D006973:Hypertension / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011674:Pulse; D063177:Pulse Wave Analysis / Q000379:methods* / Q000592:standards; D012307:Risk Factors