P1.36 A Preliminary Study for the Evaluation of Large Artery Stiffness: A Non Contact Approach

Abstract

The evaluation of carotid-to-femoral pulse transit time (PTT) is required to estimate the carotid-femoral pulse wave velocity, a parameter considered as the gold standard for the quantification of large artery stiffness. In this study we propose a novel, non contact laser-based technique (laser class II ~ laser pen), named optical Vibrocardiography (VCG), for evaluating PTT from synchronous recorded vibrations of the skin at the carotid and femoral artery site. It has been demonstrated that these skin vibrations are directly related to the radial displacement of the underlying arteries, and are hence related to the passage of the pressure pulse. In this feasibility study, measurements were performed on 14 young male healthy subjects (25.3 ± 0.8) using 2 commercially available vibrometers (Polytec Gmbh, Waldbronn , Germany). The obtained PTT values (74.86 ± 8.63 ms) were compared with PTT evaluated on the same subjects by means of applanation tonometry applied simultaneously on the same locations (75.85 ± 8.61 ms). The two techniques were very well correlated (r = 0.89, P<0.001 , Spearman rho 0.88) and values were not statistically different (p = 0.377). Our preliminary results demonstrate that laser-based non-contact measurement of pulse transit time is feasible in young healthy volunteers, and yields values that are equivalent to those measured using arterial applanation tonometry. Clinical application of this appealing non-invasive method can overcome practical and technical limitations inherent to currently used methods such as arterial applanation tonometry, ultrasound, plethysmography, requiring physical contact of the probe with the patient.