Outflow boundary conditions for 3D simulations of non-periodic blood flow and pressure fields in deformable arteries

TL;DR

This paper introduces a new method for outflow boundary conditions in 3D blood flow simulations that accounts for transient, non-periodic phenomena, improving physiological accuracy in modeling arteries.

Contribution

The authors develop a lumped parameter boundary condition approach that captures transient flow effects, extending previous models that assumed periodicity.

Findings

Method effectively models non-periodic flow in arteries.

Application to patient-specific models demonstrates physiological relevance.

Boundary conditions improve accuracy over periodic assumptions.

Abstract

The simulation of blood flow and pressure in arteries requires outflow boundary conditions that incorporate models of downstream domains. We previously described a coupled multidomain method to couple analytical models of the downstream domains with 3D numerical models of the upstream vasculature. This prior work either included pure resistance boundary conditions or impedance boundary conditions based on assumed periodicity of the solution. However, flow and pressure in arteries are not necessarily periodic in time due to heart rate variability, respiration, complex transitional flow or acute physiological changes. We present herein an approach for prescribing lumped parameter outflow boundary conditions that accommodate transient phenomena. We have applied this method to compute haemodynamic quantities in different physiologically relevant cardiovascular models, including patient-specific examples, to study non-periodic flow phenomena often observed in normal subjects and in patients with acquired or congenital cardiovascular disease. The relevance of using boundary conditions that accommodate transient phenomena compared with boundary conditions that assume periodicity of the solution is discussed.