Silicon photonics-based laser Doppler vibrometer array for carotid-femoral pulse wave velocity (PWV) measurement
Yanlu Li, Louise Marais, Hakim Khettab, Zhiheng Quan, Søren Aasmul, Rob Leinders, Ralf Schüler, Padraic E. Morrissey, Stephen E. Greenwald, Patrick Segers, Michaël Vanslembrouck, Rosa María Bruno, Pierre Boutouyrie, Peter O’Brien, Mirko De Melis, Roel Baets
Abstract
Pulse wave velocity (PWV) is a reference measure for aortic stiffness, itself an important biomarker of cardiovascular risk. To enable low-cost and easy-to-use PWV measurement devices that can be used in routine clinical practice, we have designed several handheld PWV sensors using miniaturized laser Doppler vibrometer (LDV) arrays in a silicon photonics platform. The LDV-based PWV sensor design and the signal processing protocol to obtain pulse transit time (PTT) and carotid-femoral PWV in a feasibility study in humans, are described in this paper. Compared with a commercial reference PWV measurement system, measuring arterial pressure waveforms by applanation tonometry, LDV-based displacement signals resulted in more complex signals. However, we have shown that it is possible to identify reliable fiducial points for PTT calculation using the maximum of the 2 nd derivative algorithm in LDV-based signals, comparable to those obtained by the reference technique, applanation tonometry.