title: Carotid to femoral pulse wave velocity: a comparison of real travelled aortic path lengths determined by MRI and superficial measurements.
abstract: OBJECTIVE
  Carotid-femoral pulse wave velocity (PWV) is the gold standard method for determination of arterial stiffness. PWV is assessed by dividing travelled distance by travel time. Standardization and validation of the methodology for travelled distance measurement is of crucial importance. The aim of the current investigation was to standardize and validate the methodology for travelled distance measurement.
  
  
  METHODS
  Real travelled carotid-femoral path lengths were measured with MRI in 98 healthy men/women (50% men, age 21-76 years) and are used as reference distance. This reference distance was compared with 11 estimates of aortic path length from body surface distances commonly used in PWV measurement, nine of them based on tape measures and two based on body height. Determinants of the difference between reference distance and the best body surface distance were determined. Additionally, the influence of body contours was identified.
  
  
  RESULTS
  The tape measure distance from carotid to femoral artery (CA-FA), multiplied by 0.8, yielded the best agreement with the reference aortic path length [difference 0.26 cm (SD 3.8), not statistically significant]. Thirty percent of the variation in difference between the reference distance and tape measure distance (CA-FA × 0.8) was explained by age. Adding BMI increased this number to 34%.
  
  
  CONCLUSIONS
  The tape measure distance from CA-FA, multiplied by 0.8, corresponds best with the real travelled aortic path length. This distance is moderately (yet statistically significantly) influenced by age and minimally by BMI.
authors.affiliation: Heymans Institute of Pharmacology, Ghent University Hospital Ghent, Belgium. sofieam.huybrechts@ugent.be
authors.forename: Sofie A M
authors.initials: SA
authors.lastname: Huybrechts
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Devos
authors.forename: Sebastian J
authors.initials: SJ
authors.lastname: Vermeersch
authors.forename: Dries
authors.initials: D
authors.lastname: Mahieu
authors.forename: Eric
authors.initials: E
authors.lastname: Achten
authors.forename: Tine L M
authors.initials: TL
authors.lastname: de Backer
authors.forename: Patrick
authors.initials: P
authors.lastname: Segers
authors.forename: Luc M
authors.initials: LM
authors.lastname: van Bortel
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001011:Aorta / Q000033:anatomy & histology* / Q000502:physiology; D001783:Blood Flow Velocity / Q000502:physiology; D001827:Body Height; D015992:Body Mass Index; D001830:Body Surface Area; D002339:Carotid Arteries / Q000033:anatomy & histology / Q000502:physiology*; D005260:Female; D005263:Femoral Artery / Q000033:anatomy & histology / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011673:Pulsatile Flow / Q000502:physiology*; D015203:Reproducibility of Results; D013997:Time Factors