Evaluation of endothelial response to reactive hyperaemia in peripheral arteries using a physiological model

Abstract

Non-invasive measurement of flow-mediated dilation (FMD) in the brachial artery for assessing endothelial function is costly and operator-dependent, limiting its application to research cases. In this paper, an approach based on a physiological model between normalized central blood pressure and finger photoplethysmogram is presented. Baseline model parameters are estimated using a genetic algorithm in 30 subjects consisting of ten normal blood pressure (BP), ten high-BP and ten elderly volunteers. Beat-to-beat fitness values after reactive hyperaemia are calculated using baseline (before cuff occlusion) data. Results show that stimulus-induced changes are fairly described with a first order dynamic. The time constant of this first order system is significantly larger for normal BP compared to high BP (p-value = 0.004) and elderly subjects (p-value = 0.01). Our findings hint to the potential of the proposed physiological, model-based approach for evaluating cardiovascular health using FMD.