| Summary: | Objectives: Aortic pulse wave velocity (PWV) is usually estimated by sequential (ECG referenced) carotid-femoral tonometry using the SphygmoCor system (Atcor, Australia). This can be technically challenging and operator dependant. Here we evaluate a simple, operator independent method of estimating central PWV based upon simultaneous recording from upper arm and thigh cuffs (Vicorder, Skidmore Medical, UK).
Methods: PWV was measured using the Vicorder and SphygmoCor systems (each measurement in triplicate) in 133 adults (mean age 53, range 21–70 years). SphymoCor PWV was calculated using the suprasternal notch (sn) to femoral distance. Two distances were used to calculate PWV from the Vicorder: cuff to cuff measured with arm at the side (cc) and sn to thigh cuff minus sn to arm cuff (notch to cuff difference, ncd). Reproducibility of the Vicorder was further assessed by repeat measures in 9 subjects.
Results: Mean values of PWV obtained by SphygmoCor, Vicorder (cc) and Vicorder (ncd) were 9.0±1.6, 12.0±2.8 and 8.7±1.9m/s respectively. Both Vicorder (cc) and Vicorder (ncd) were closely correlated with SphygmoCor PWV (each r=0.7). The mean difference between SphygmoCor and Vicorder (ncd) was 0.2±1.4m/s. The within subject standard deviation for repeated measures for Vicorder (ncd) was 0.54m/s.
Conclusion: There is a high correlation between values obtained using the Vicorder and SphygmoCor and good reproducibility for Vicorder measurements. Differences between the methods are likely due to errors in the estimation of path length. Vicorder PWV is quick and easy to perform with minimal training and offers a simple alternative to applanation tonometry.
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