Article

Annals of Biomedical Engineering

, Volume 38, Issue 3, pp 841-853

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Simulation of the Three-Dimensional Hinge Flow Fields of a Bileaflet Mechanical Heart Valve Under Aortic Conditions

  • Hélène A. SimonAffiliated withSchool of Chemical and Biomolecular Engineering, Georgia Institute of Technology
  • , Liang GeAffiliated withUniversity of California San Francisco
  • , Fotis SotiropoulosAffiliated withSt. Anthony Falls Laboratory, Department of Civil Engineering, University of Minnesota
  • , Ajit P. YoganathanAffiliated withSchool of Chemical and Biomolecular Engineering, Georgia Institute of TechnologyThe Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology Email author 

Abstract

Thromboembolic complications of bileaflet mechanical heart valves (BMHV) are believed to be due to detrimental stresses imposed on blood elements by the hinge flows. Characterization of these flows is thus crucial to identify the underlying causes for complications. In this study, we conduct three-dimensional pulsatile flow simulations through the hinge of a BMHV under aortic conditions. Hinge and leaflet geometries are reconstructed from the Micro-Computed Tomography scans of a BMHV. Simulations are conducted using a Cartesian sharp-interface immersed-boundary methodology combined with a second-order accurate fractional-step method. Physiologic flow boundary conditions and leaflet motion are extracted from the Fluid–Structure Interaction simulations of the bulk of the flow through a BMHV. Calculations reveal the presence, throughout the cardiac cycle, of flow patterns known to be detrimental to blood elements. Flow fields are characterized by: (1) complex systolic flows, with rotating structures and slow reverse flow pattern, and (2) two strong diastolic leakage jets accompanied by fast reverse flow at the hinge bottom. Elevated shear stresses, up to 1920 dyn/cm2 during systole and 6115 dyn/cm2 during diastole, are reported. This study underscores the need to conduct three-dimensional simulations throughout the cardiac cycle to fully characterize the complexity and thromboembolic potential of the hinge flows.

Keywords

Pulsatile numerical simulations Fluid mechanics Pivot Computational fluid dynamics CFD Physiologic conditions