Sinus Hemodynamics Variation with Tilted Transcatheter Aortic Valve Deployments.

Area of Science:

• Cardiovascular Engineering
• Biomedical Fluid Dynamics
• Medical Device Technology

Background:

• Leaflet thrombosis is a known complication of transcatheter aortic valve replacement (TAVR).
• Sinus hemodynamics, including shear stress and washout, are critical for preventing thrombus formation on TAV leaflets.
• The impact of TAV axis misalignment on sinus hemodynamics and thrombosis risk is not well understood.

Purpose of the Study:

• To investigate the effect of TAV angular misalignment relative to the aortic root axis on sinus flow stasis.
• To determine how TAV axis misalignment influences hemodynamics, potentially leading to leaflet thrombosis.

Main Methods:

• In vitro assessment of sinus hemodynamics using particle-image velocimetry in a 3D printed aortic root model.
• Implantation of an Edwards SAPIEN3 TAV in three angular misalignment conditions: untilted, tilted towards the sinus, and tilted away from the sinus.
• Calculation of TAV hemodynamics, sinus vortex dynamics, leaflet shear stress, and sinus blood washout time.

Main Results:

• No significant difference in pressure gradients was observed between groups.
• Both tilted TAV positions showed significantly reduced blood velocity and vorticity in the sinuses.
• Decreased shear stress probability near leaflets in tilted positions indicates increased stasis.
• TAV tilted away from the sinus presented the most unfavorable scenario with significantly poorer washout.

Conclusions:

• TAV angular misalignment significantly alters sinus hemodynamics, reducing velocity and vorticity.
• Misalignment increases the risk of sinus flow stasis and potentially leaflet thrombosis.
• TAV axis alignment is a crucial factor influencing leaflet thrombosis risk by modifying sinus hemodynamics.