Background: Arterial stiffness is a risk factor for cardiovascular disease. Carotid-femoral pulse wave velocity (cfPWV), the ‘gold standard’ measurement, is traditionally assessed using applanation tonometry. The Vicorder is a novel apparatus that estimates PWV, using non-invasive oscillometric assessment of the pulse waveform, at two arterial sites simultaneously. There is limited data on precision, and no data on visit-to-visit reproducibility of Vicorder-assessed PWV.

Methods: We measured precision [intravisit within-subject variability, quantified using coefficient of variation (CoV) and intraclass correlation coefficient (ICC)], and reproducibility (visit-to-visit differences assessed by Bland-Altman method). Both parameters were estimated in triplicate by a single investigator, using a standardised Vicorder protocol. Some volunteers had repeat assessment at 7±2 days.

Results: In 48 volunteers (age:62±8), single visit variability was smaller for bfPWV versus cfPWV (CoV 3.19% and 8.19%; ICC 0.99 and 0.84, respectively), and comparable with heart rate variability (CoV 2.57, ICC 0.99). In 11 volunteers with repeat measurements (age:54±10), the mean difference (limits of agreement) between visits was low for cfPWV and bfPWV [0.1 (−0.64 to 0.84), and 0.3 (−2.38 to 2.98), respectively].

Conclusions: We report slightly higher single-visit variability compared to previous studies (CoV-2.8%-Hickson-2009, 2.67%-Everett-2012), possibly a reflection of our older population. Nonetheless, Vicorder PWV estimates are precise (low CoV, high ICC), and cfPWV (range:5.15–8.60) shows good visit-to-visit reproducibility (narrow limits of agreement <1.5m/s). Despite higher precision/lower variability, bfPWV was less reproducible, having wider limits of agreement. Further studies are warranted to establish validity, reliability and clinical applicability of Vicorder-PWV measurements in different populations.