Fluid-structure interaction of deformable aortic prostheses with a bileaflet mechanical valve

Area of Science:

• Cardiovascular Surgery
• Biomedical Engineering
• Computational Fluid Dynamics

Background:

• The Bentall procedure is a complex aortic surgery involving aortic valve and root replacement.
• Graft geometry, specifically standard straight versus Valsalva grafts, may influence hemodynamics and stress distribution.
• Understanding stress concentration at coronary artery anastomoses is crucial for preventing complications.

Purpose of the Study:

• To investigate the impact of aortic graft geometry on blood flow dynamics during the Bentall procedure.
• To evaluate stress concentration near the coronary artery suture lines for different graft types.
• To compare the performance of standard straight grafts versus Valsalva grafts.

Main Methods:

• Development of a three-dimensional numerical model using the immersed boundary technique.
• Simulation of blood flow under physiological pulsatile conditions.
• Inclusion of interactions between fluid dynamics, mechanical heart valve leaflets, and aortic root deformation.

Main Results:

• Graft geometry exhibited minimal influence on the dynamics of bileaflet mechanical heart valve leaflets.
• The Valsalva graft resulted in approximately half the stress levels near the coronary-root anastomoses compared to the standard straight graft.
• Numerical simulations provided detailed insights into flow patterns and stress distributions.

Conclusions:

• The Valsalva graft offers a significant biomechanical advantage by reducing stress at coronary anastomoses.
• Graft geometry plays a critical role in mitigating stress concentrations in complex aortic reconstructions.
• This study supports the use of Valsalva grafts for improved outcomes in Bentall procedures.