Skip to Main Content
 

Global Search Box

 
 
 

ETD Abstract Container

Abstract Header

Fluid Mechanics of Transcatheter Aortic Valve Replacement

Hatoum, Hoda
http://orcid.org/0000-0001-5538-8960
http://rave.ohiolink.edu/etdc/view?acc_num=osu1541781379381912

Abstract Details

2018, Doctor of Philosophy, Ohio State University, Mechanical Engineering.
Transcatheter aortic valve (TAV) replacement (TAVR) and transcatheter valve-in-valve (ViV) procedures represent less invasive solutions to some of the most important cardiac diseases such as aortic stenosis and aortic insufficiency than the conventional surgical aortic valve surgery and redo surgery for high-risk patients. However, TAVR is associated with several recurring adverse effects like residual stenosis, paravalvular leakage, coronary obstruction and reduced leaflet mobility. Much of the adverse outcomes are fundamentally related to blood flow which is pulsatile, turbulent and unsteady in nature and is further complicated by the time dependent variability of the valve orifice area. The interaction of this complex jet and its surrounding more complex geometry and anatomy leads to complicated local fluid dynamics such as shear layers, vortex formation and propagation, flow separation, flow stagnation and recirculation regions. The objective of this dissertation is to introduce new knowledge that highlights key mechanisms of how patient-specific parameters along with valve types and configurations dictate local flow behavior as well as valve function (pressure gradients, effective orifice areas etc.). The overarching hypothesis driving this research is that consideration of patient-specific parameters along with valve types and configurations significantly dictate local flow behavior as well as valve function. To test this hypothesis, state-of-the-art methods using patient-specific 3D printing, time-resolved particle image velocimetry (PIV) measurements and high-speed imaging were performed in both native, as well as TAVR configurations. Pressure gradients, effective orifice areas, shear stress, leakage or regurgitant fractions, pinwheeling indices, velocity and vorticity fields, sinus washout, Reynolds shear stresses and turbulent kinetic energy were calculated. These studies have shown that: (1) Sinus flow dynamics are highly sensitive to valve-root interaction. (2) Decreased flow and shear stress in valve-in-valve procedures indicate a higher risk of leaflet thrombosis secondary to flow stasis, perhaps more so in the non-coronary sinus. (3) Patient’s low coronary arteries can dictate the optimal transcatheter aortic valve types to mitigate coronary obstruction risk. (4) Inflow tissue ingrowth and calcification – that are inherently patient-specific - greatly influence valve-in-valve performance due to dynamic effects that result in an anomalous performance different than that seen in vivo. (5) Comparing patient-specific models with idealized rigid models, valve hemodynamics were drastically different mainly in terms of the turbulence associated with every model and to every valve type. The intellectual merit of this study is the development of new mechanistic understanding about (a) how aortic sinus flow patterns are altered after TAVR affecting therefore flow stasis regions (b) how TAV types whether balloon expandable short profile valves or self-expandable long profile valves and valve deployment positions alter sinus flow characteristics and (c) how patient-specific parameters such as sinus geometries and valve and leaflet calcification distribution patterns affect main flow, sinus flow patterns and adverse effects in TAVR and ViV. This proposed research lays groundwork for knowledge that can be translated to update the currently adopted clinical guidelines beyond bench studies.
lakshmi Prasad Dasi (Advisor)
Samir Ghadiali (Committee Member)
Rizwan Ahmad (Committee Member)
Scott Lilly (Committee Member)
Theordore Chao (Committee Member)
286 p.
Mechanical Engineering
Transcatheter aortic valve; fluid mechanics; sinus flow; pulsatile flows; TAVR; thrombosis

Recommended Citations

Citations

  • Hatoum, H. (2018). Fluid Mechanics of Transcatheter Aortic Valve Replacement [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1541781379381912

    APA Style (7th edition)

  • Hatoum, Hoda. Fluid Mechanics of Transcatheter Aortic Valve Replacement. 2018. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1541781379381912.

    MLA Style (8th edition)

  • Hatoum, Hoda. "Fluid Mechanics of Transcatheter Aortic Valve Replacement." Doctoral dissertation, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1541781379381912

    Chicago Manual of Style (17th edition)

osu1541781379381912
323
© 2018, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.