Abstract 13473: Increased Blood Residence Time on Transcatheter Aortic Valve Leaflets as a Precursor Mechanism to Leaflet Thrombosis following Valve-in-Valve Procedure: A Patient-Specific Simulation Study
Introduction: Leaflet thrombosis following valve-in-valve (ViV) procedures has been increasingly recognized. Nevertheless, the underlying mechanisms are not well-addressed and remained unclear.
Hypothesis: Unlike surgical bioprostheses, the aortic portion of the transcatheter aortic valve (TAV) frame is circumferentially surrounded by degenerated bioprostheses in ViV (Fig 1 a-b). The geometric confinement of the TAV leaflets increases the blood residence time (BRT) on the leaflets. This acts as a precursor mechanism to the thrombus formation.
Methods: A patient-specific geometry of the left ventricle, aorta, and coronary arteries was reconstructed from computed tomographic angiography (CTA) images using Simpleware software (Fig 1c). Two computational models representing a surgical bioprosthesis and a TAV in ViV setting were developed in the patient-specific geometry. 3D flow fields were obtained via a one-way fluid-solid interaction modeling approach. Thereafter, a particle tracking procedure was applied to calculate BRT on the leaflets. Finally, statistical analysis was performed to compare the BRT values between the two models.
Results: Tracking of the blood particles in close proximity of the leaflets demonstrated significantly longer BRT on the aortic side of the leaflets in the ViV setting than surgical bioprosthesis (Fig 1d). During systole and diastole, the amount by which the mean BRT was higher for ViV than surgical valve was 341% and 90%, respectively (p<0.001).
Conclusions: The results of this study show that geometric confinement of TAV in ViV disrupts flow between the leaflets and the aortic sinuses, and increases the likelihood of thrombogenesis.
Author Disclosures: K. Vahidkhah: None. S. Javani: None. M. Abbasi: None. P.N. Azadani: None. A. Tandar: None. A.N. Azadani: None.
- © 2016 by American Heart Association, Inc.