Noncoaxial Transcatheter Aortic Valve Deployment Creates Cusp-Specific Thrombogenic Microenvironments Through Altered...

Area of Science:

• Cardiovascular Engineering
• Biomedical Imaging
• Hemodynamics

Background:

• Transcatheter aortic valve replacement (TAVR) is a key treatment for aortic stenosis.
• Adverse outcomes like leaflet thrombosis and hypoattenuating leaflet thickening (HALT) remain significant concerns post-TAVR.
• Valve canting can disrupt local hemodynamics, potentially promoting thrombotic conditions.

Purpose of the Study:

• To investigate how transcatheter heart valve (THV) canting affects cusp-specific sinus flow and washout.
• To determine if THV canting promotes localized thrombogenic microenvironments leading to leaflet thrombosis.
• To analyze the relationship between deployment angle and thrombus formation using advanced imaging and simulation.

Main Methods:

• Utilized a patient-derived aortic root model to simulate TAVR.
• Evaluated THV canting at -10° (anti-curvature), 0° (neutral), and +10° (along-curvature).
• Employed particle image velocimetry for flow field analysis and whole-blood loop experiments for histologic assessment of thrombus.

Main Results:

• Canting altered systolic jet orientation and sinus recirculation, with the most constrained cusp showing increased stasis and slower washout.
• Anti-curvature canting in the right coronary cusp significantly increased stagnant flow regions and prolonged washout time.
• Histology confirmed surface-adherent platelet/fibrin thrombus in poorly washed areas, particularly in the right coronary cusp with anti-curvature canting.

Conclusions:

• Modest noncoaxial THV deployment can create localized thrombogenic microenvironments not detected by global hemodynamic parameters.
• Deployment configuration is a modifiable factor influencing post-TAVR leaflet thrombosis risk.
• Findings suggest that optimizing THV alignment may mitigate the risk of leaflet thrombosis and HALT.