A comparative computational study of blood flow through prosthetic heart valves using the finite element method

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Computational Mechanics

Background:

• Prosthetic heart valves are crucial for patients with valvular heart disease.
• Understanding the hemodynamic performance of different prosthetic valve designs is essential for optimizing patient outcomes.
• Previous studies have utilized various methods to evaluate valve performance, but detailed numerical simulations offer unique insights.

Purpose of the Study:

• To numerically simulate and compare the steady blood flow characteristics through three common prosthetic heart valve types: disk, tilting-disk, and ball.
• To analyze the velocity, pressure, and stress fields within these valves under varying physiological conditions.
• To evaluate valve performance based on energy loss and maximum shear stress, comparing results with in vitro data.

Main Methods:

• The finite element method was employed for numerical simulation of steady blood flow.
• Simulations were conducted for disk-type, tilting-disk, and ball-type prosthetic heart valves in the aortic position.
• Reynolds numbers were increased up to 900, 1500, and 2000 for the respective valve types.

Main Results:

• Detailed computer graphics of velocity fields illustrated accelerated flow, recirculation, and stagnation zones around the prostheses.
• Maximum wall shear stresses downstream from the sewing ring were 55, 18, and 33 dyn cm⁻² for disk, tilting-disk, and ball valves, respectively.
• Maximum shear stresses near the occluder were 38, 30, and 47 dyn cm⁻² for the respective valve types, with significant variations in energy loss.

Conclusions:

• The study provides a detailed numerical comparison of hemodynamic performance for three prosthetic heart valve types.
• Significant differences in flow patterns, shear stress distribution, and energy loss were observed among the valve designs.
• The computed velocity and stress fields align with existing in vitro evaluations, validating the simulation approach.