Inlet boundary conditions for blood flow simulations in truncated arterial networks

• Published in: Journal of biomechanics 2011-03, Vol.44 (5), p.897-903
• Main Authors: Willemet, Marie, Lacroix, Valérie, Marchandise, Emilie
• Format: Article
• Language: English
• Subjects: 1D models; Aged; Algorithms; Arteries - pathology; Backward waves; Biological and medical sciences; Blood flow; Blood Flow Velocity; Boundary conditions; Bypass graft; Computer Simulation; Computerized, statistical medical data processing and models in biomedicine; Femur - pathology; Finite Element Analysis; Geometry; Hemodynamics; Humans; Inlet boundary condition; Inlets; Linear Models; Lower-limb model; Male; Mathematical models; Medical management aid. Diagnosis aid; Medical sciences; Networks; Physical Medicine and Rehabilitation; Pressure; Simulation; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Three dimensional; Tibia - pathology; Ultrasonography, Doppler - methods; Vascular surgery: aorta, extremities, vena cava. Surgery of the lymphatic vessels; Veins & arteries; Velocity; Wave separation
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2010.11.036

Abstract In the context of patient-specific cardiovascular applications, hemodynamics models (going from 3D to 0D) are often limited to a part of the arterial tree. This restriction implies the set up of artificial interfaces with the remaining parts of the cardiovascular system. In particular, the inlet boundary condition is crucial: it supplies the impulsion to the system and receives the reflected backward waves created by the distal network. Some aspects of this boundary condition need to be properly defined such as the treatment of backward waves (reflected or absorbed) and the value of the imposed hemodynamic wave (total or forward component). Most authors prescribe as inlet boundary condition (BC) the total measured variable (pressure, velocity or flow rate) in a reflective way. We show that with this type of inlet boundary condition, the model does not produce physiological waveforms. We suggest instead to prescribe only the forward component of the prescribed variable in an absorbing way. In this way, the computed reflected waves superpose with the prescribed forward waves to produce the total wave at the inlet. In this work, different inlet boundary conditions are implemented and compared for a 1D blood flow model. We test our boundary conditions on a truncated arterial model presented in the literature as well as on a patient-specific lower-limb model of a femoral bypass. We show that with this new boundary condition, a much better fitting is observed on the shape and intensity of the simulated pressure and velocity waves.