Assessment of peripheral vascular function with photoplethysmographic pulse amplitude

Abstract Background Vasodilation of the peripheral arteries after reactive hyperaemia depends in part on the release of nitric oxide from endothelial cells. Previous studies mainly employed a fingertip tonometric device to derive pulse wave amplitude (PWA) and, therefore, measure PWA hyperaemic changes. Another approach to derive information about PWA is based on photoplethysmography (PPG). We sought to evaluate the correlates of digital PPG PWA hyperaemic responses as a measure of peripheral vascular function. Methods Using a fingertip PPG device, we measured digital PWA in 63 subjects enrolled in a population study (55.5% women; mean age, 55 years; 58.7% hypertensive) at baseline and at 30-s intervals for 4 min during reactive hyperaemia induced by a 5-min forearm cuff occlusion. We performed stepwise regression to identify correlates of the hyperaemic response ratio for each 30-s interval after cuff deflation. Results With age forced into the models, the explained variance for the PPG PWA ratio totalled from 17.1% at the 210–240-s time interval to 31.3% at 30–60-s time interval. The hyperaemic response at each 30-s interval was significantly higher in women compared to men ( P