Non-invasive characterization of total arterial compliance by simultaneous acquisition of pressure and flow: Advantages of the pulse pressure method

We compare three proposed indices of total arterial compliance (Ctot) in normal volunteers (n-9) and patients with coronary artery disease (n=14) using a non-invasive approach (echo-Doppler and carotid tonometry): (1) the pulse pressure method (PPM), (2) the area method (AM) and (3) the stroke volume-to-pulse pressure ratio (SV/PP). The best agreement was found between the PPM and SV/PP. Compliance estimates were lower in the patient group (PPM: 1.2±0.4 vs. 1.6±0.2; AM: 1.6±0.6 vs. 2.8±1.3; SV/PP: 1.8±0.6 vs. 2.4±0.4), being older (64±14 vs. 35±4 y) and with known atherosclerosis. The best correlation between compliance and age was found with PPM (r²=0.52). AM varied with the chosen computation interval in diastole. These preliminary data describing the very first use of the PPM on non-invasive human recordings suggest that PPM could be a more robust estimator of Ctot than the widely used AM, and that SV/PP could be a reasonable simpler surrogate.