A Noncontact Approach for the Evaluation of Large Artery Stiffness: A Preliminary Study

BACKGROUND: The time from carotid to femoral pulse wave propagation (pulse transit time (PTT)) is required to estimate the carotid-femoral pulse wave velocity (PWV), a reliable index for evaluating large artery stiffness. METHODS: In this work, we propose a novel, noncontact laser-based technique, named optical vibrocardiography (VCG), for evaluating PTT from synchronous recordings of the motion of the skin on the neck and the groin. These measurements, which have been demonstrated to be related to the radial displacement of the underlying blood vessels, were performed on 14 healthy subjects. As validation, applanation tonometry was performed to determine PTT between the carotid and the femoral artery. RESULTS: PTT evaluated by VCG was not different from applanation tonometry (74.86 +/- 8.63 ms vs. 75.85 +/- 8.61 ms, P = 0.377). CONCLUSIONS: Our preliminary results demonstrate that laser-based noncontact measurement in young healthy volunteers is feasible, and yields PTTs that are equivalent to those measured using arterial applanation tonometry. Its clinical application can overcome limitations inherent to a contact method like arterial tonometry.