title: The Vicorder device compared with SphygmoCor in the assessment of carotid-femoral pulse wave velocity in patients with peripheral arterial disease.
abstract: To assess the reliability and reproducibility of the Vicorder's carotid-femoral pulse wave velocity (cfPWV) measurements in patients with peripheral arterial disease (PAD) and to compare between cfPWV measurements obtained using the Vicorder with those obtained using the SphygmoCor device as a reference. Some 30 patients with PAD (23 men, mean age 64.9±7.5) underwent cfPWV measurement twice by a single investigator during one visit using the Vicorder and the SphygmoCor according to the manufacturer's instructions. Intra-rater reproducibility for each device was assessed using intraclass correlation coefficients (ICC) and Bland-Altman method. The latter was also used to compare between the two devices. The mean difference (s.d.) between repeated measurements was 0.03±0.92 m s(-1), P=0.85 and 0.01±0.54 m s(-1), P=0.91 for the SphygmoCor and Vicorder, respectively. Measurements of cfPWV were highly reproducible using both devices (ICC=0.94 and 0.92, for the Vicorder and SphygmoCor, respectively). Limits of Agreement using the Bland-Altman method were -1.07 to 1.09 m s(-1) and -1.79 to 1.85 m s(-1) for the Vicorder and the SphygmoCor, respectively. Bland-Altman plots indicated that 90% of the cfPWV measurements using the Vicorder and 93% of the measurements using the SphygmoCor fell within two s.d.s of the mean difference. Transit time (TT) differed significantly between the two devices (mean difference 30±9.2 m s, P<0.001), with the Vicorder recording higher values. Nevertheless, the two devices recorded nearly similar cfPWV measurements (mean difference -0.69±1.6 m s(-1), P=0.02) with 97% of cfPWV values falling within two s.d. values of the mean difference on Bland-Altman plot. Both devices generated highly reproducible cfPWV measurements in patients with PAD and were in good agreement when compared with each other. However, the discrepancy in TT between the two devices lead to the Vicorder producing lower values of cfPWV at high values produced by the SphygmoCor.
authors.affiliation: Academic Vascular Surgical Unit, Hull York Medical School and University of Hull, Hull, UK. yousef.shahin@yahoo.co.uk
authors.forename: Yousef
authors.initials: Y
authors.lastname: Shahin
authors.forename: Hashem
authors.initials: H
authors.lastname: Barakat
authors.forename: Rachel
authors.initials: R
authors.lastname: Barnes
authors.forename: Ian
authors.initials: I
authors.lastname: Chetter
mesh_terms: D000368:Aged; D002339:Carotid Arteries / Q000503:physiopathology*; D004864:Equipment and Supplies / Q000592:standards; D005260:Female; D005263:Femoral Artery / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008365:Manometry / Q000295:instrumentation / Q000379:methods*; D008875:Middle Aged; D015588:Observer Variation; D009991:Oscillometry / Q000295:instrumentation / Q000379:methods*; D058729:Peripheral Arterial Disease / Q000503:physiopathology*; D063177:Pulse Wave Analysis; D015203:Reproducibility of Results; D013997:Time Factors