P2.24 Estimation of Arterial Mechanical Properties Based on a Patient Specific Wave Propagation Model

Abstract

Background

Arterial stiffness can be assessed using pulse wave velocity (PWV). However, distance measurement introduces an error and an average PWV is considered although arterial stiffness increases distally. A patient specific one-dimensional wave propagation model may reveal details of pressure wave propagation phenomena and mechanical properties of arteries.

Methods

For 6 healthy volunteers, ultrasound wall distension (WD), blood pressure (BP) waveform and blood velocity were assessed at 5 positions along the leg. Blood volume flow (BVF) for each position was estimated assuming Womersley profile. The Young’s moduli and diameters of the arteries were derived from the BP and WD. The BVF at the iliac artery (IA) is used as input for the simulations. The in-vivo results were compared with simulated BVF and BP curves to adapt the model parameters iteratively.

Results

The group average diameter equals 7.4±0.6 for the IA, 1.9±0.8 for the posterior tibial (PTA) and 1.7±0.5mm for the pedal (PDA) artery. The ratio IMT/diameter increases along the arterial tree, from 7.5% to 21.1% and 27.5% in the IA, PDA and PTA, respectively. The distensibility equals 0.39±0.07 and 0.36±0.09MPa^-1 at the IA and PDA; the PWV over IA to PDA segment is 7.4±1.0m/s. The distensibility resulting from the iterative method is 20% smaller than the first estimate based on the measurements while the PWV was the same.

Conclusion

The results show that the shape of simulated BVF is comparable with in-vivo estimations and that the wave propagation model can be used to estimate more accurately arterial mechanical properties.