Objective:
Heart-femoral pulse wave velocity (hf-PWV), estimated from the Cardio-Ankle Vascular Index device (VaSera-1500) by combining phonocardiogram with pulse signals detected by thigh cuffs, as opposite to carotid-femoral pulse wave velocity (cf-PWV), includes the stiffness of the ascending aortic segment. We sought to investigate the repeatability and main correlates of hf-PWV, and to compare the results with cf-PWV.
Design and method:
Hf-PWV and cf-PWV were obtained in 85 volunteers (n = 30 < 30 years, n = 30 30–60 years, n = 25 > 60 years), according to ARTERY society guidelines for validation of non-invasive devices (Artery Research 2010;4:34–40). Heart-femoral transit time was calculated as the time lag between aortic opening to pulse arrival to the thigh cuff. Distance was taken as 0.8 x direct distance between the carotid and femoral pulses. For comparison with cf-PWV, heart-femoral transit time was re-calculated after subtracting the transit times needed to travel: (1) the distance from the femoral pulse to the top of thigh cuff; (2) the distance from the aortic valve to the carotid pulse. These two transit times were derived from age- and sex-specific values published elsewhere (Sugawara J et al, J Hypertens 2014;32:881–889).
Results:
Cf-PWV and hf-PWV were closely correlated (R = 0.85, p < 0.01) and showed similar degrees of association with age (R = 0.75 and R = 0.83), height (R = 0.20 and R = 0.26) and mean arterial pressure (R = 0.53 and R = 0.54). In absolute terms, after re-calculation of transit time, hf-PWV was significantly lower than cf-PWV (mean difference −2.06 ± 1.0 m/s, p < 0.01), and showed a tendency toward increasing difference at increasing PWV values (Figure 1). Hf-PWV showed high within- (coefficient of variation (CV) 4.6%) and between-observer (CV 6.0%) reproducibility.
Conclusions:
Hf-PWV, measured through a semi-automated device which combines phonocardiogram with pulse detection with a thigh cuff, showed high reproducibility, was closely correlated with cf-PWV, and showed similar associations with variables classically associated with arterial stiffness. In absolute terms, hf-PWV was significantly lower than cf-PWV; such difference increased at increasing age, potentially reflecting the lower age-dependency of stiffness of the ascending aorta. Further studies aiming at evaluating the clinical and prognostic significance of hf-PWV are warranted.
