In vitro flow dynamics of four prosthetic aortic valves: a comparative analysis

Area of Science:

• Biomedical Engineering
• Cardiovascular Science
• Fluid Dynamics

Background:

• Prosthetic heart valves are crucial for treating valvular heart disease.
• Understanding the hemodynamic performance of different valve designs is essential for patient outcomes.
• In vitro studies provide a controlled environment to analyze complex flow patterns.

Purpose of the Study:

• To comprehensively map and compare the velocity fields downstream of four distinct prosthetic heart valve types.
• To evaluate hemodynamic parameters including pressure drop, shear stress, and maximum velocities.
• To assess the influence of steady versus pulsatile flow on valve performance.

Main Methods:

• In vitro analysis of four prosthetic heart valves: Björk-Shiley convexo-concave, Smeloff-Cutter caged ball, St. Jude Medical bileaflet, and Ionescu-Shiley bioprosthesis.
• Utilized laser Doppler anemometry to map velocity fields across the entire cross-section of a model aortic root.
• Conducted experiments under both steady and pulsatile flow conditions.

Main Results:

• Significant variations in large-scale flow structures were observed among the four prosthetic heart valves under pulsatile flow.
• Steady flow velocity profiles only approximated pulsatile profiles during midsystole.
• Comparative data on pressure drop, shear stress, and maximum velocities were generated for each valve type.

Conclusions:

• Prosthetic heart valve design significantly influences downstream hemodynamics.
• Pulsatile flow introduces complex flow structures not fully replicated by steady flow analysis.
• The findings provide critical data for the selection and design of prosthetic heart valves.