Photoplethysmographic assessment of the pressure-compliance relationship for the radial artery

Abstract

The compliance of the radial artery has been shown to be useful as an early predictor of vascular diseases. 12 subjects were studied to estimate the pressure-area (P-A) and pressure-compliance (P-C) relationships of the radial artery over a wide pressure range. The P-A relationship was modeled using an asymmetrical arctangent function and the P-C relation was derived as its derivative. Model parameters were found by nonlinear fitting using arterial pressure changes from the Millar tonometer and volume (cross-section area) changes from the photoplethysmograph (University of Tartu), both adjusted on the radial artery. In average over the experiments, the maximum compliance value was 0.15 mm2/mm Hg, the mean location of the maximum compliance point was -1.0 mm Hg; the left and right half-maximum widths of the model were 13.6 and 25.5 mm Hg, respectively. Results show a relatively large variance in bell-shaped curves of the radial P-C relationship. © 2010 International Federation for Medical and Biological Engineering.