Pulse wave propagation and velocity in aneurysmal aorta using FSI model

Abstract

The pulse wave velocity (PWV) has been shown to be associated with the properties of blood vessels and a cardiovascular risk factor, such as an aneurysm. The global PWV estimation is applied in conventional clinical diagnosis. However, the geometry of the blood vessel changes along the wave traveling path and the global PWV estimation may not always detect regional wall changes resulting from cardiovascular diseases. In this study, a fl uid structure interaction (FSI) analysis was applied on straight-shaped aortas with and without an aneurysm with the aim of determining the effects of the aneurysm size and the ratio of the aneurysm to wall modulus on the pulse wave propagation and velocity. The characterization for each stage of the aneurysmal aorta was simulated by progressively increasing aortic stiffness and aneurysm size. The pulse wave propagations and velocities were estimated from a two-dimensional spatial-temporal plot of the normalized wall displacement based on elastic deformation. The supra- and infra-aneurysm PWVs of aneurysmal aortic walls were found to be up to 58±14% and 13±10%, respectively, which were different from the PWV of a normal aortic wall. The combined quantitative and qualitative parameters, i.e., PWV, magnitude of wall displacement on the wave, width of the standing wave and wave propagations, were used to distinguish the characterization of the normal and aneurysmal aortic walls and shown to be relevant regional markers that can be utilized in clinical diagnosis.

Keywords

• aneurysm
• heterogeneous aortic wall
• pressure wave
• stiffness