Comparison of two instruments measuring carotid-femoral pulse wave velocity: Vicorder versus SphygmoCor

BACKGROUND: The carotid-femoral pulse wave velocity (PWVcf) is used as an indicator of arterial stiffness. It is often measured using applanation tonometry, for instance with the SphygmoCor. In young children, this method is difficult to perform. Therefore, techniques are needed that are less dependent on patient compliance. The Vicorder device uses the oscillometric technique to measure the PWVcf and is thought to be less time consuming and less dependent on operator skills. OBJECTIVE: To compare the PWVcf measured by an extensively used device (SphygmoCor) and the Vicorder in adults initially. METHODS: Thirty-eight healthy volunteers (20 men, mean age 48 +/- 13.1 years) participated in this cross-sectional study. The PWVcf was assessed twice using the SphygmoCor and the Vicorder by a single investigator during one visit. Intra-rater reproducibility of each instrument and comparison between the two instruments were assessed by the Bland-Altman method. RESULTS: The mean difference (95% confidence interval) between repeated measurements was 0.09 (-0.20 to 0.38) m/s and 0.24 (-0.55 to 1.03) m/s, for the SphygmoCor and Vicorder, respectively. The Limits of Agreement (LoA) were -1.53 to 1.71 m/s and -4.24 to 4.72 m/s, for the SphygmoCor and Vicorder, respectively. The mean PWVcf measured by the Vicorder was 0.58 (-0.20 to 1.35) m/s higher than the PWVcf measured by the SphygmoCor. The LoA between the two instruments were -3.50 to 4.66 m/s. CONCLUSION: The LoA of both instruments exceed a value of 1.5 m/s. The LoA of the Vicorder PWVcf measurements are considered too wide for using this technique reliably in adults or in children.