Ex vivo assessment of bicuspidization repair in treating severe functional tricuspid regurgitation: a stereo-scopic PIV study

Abstract

There has been a resurgence of interest in the treatment of severe functional tricuspid regurgitation (FTR) due to the awareness of its poor outcomes and potential percutaneous therapies. Kay bicuspidization has been adapted in percutaneous therapies but its clinical outcome remains uncertain. The present study evaluates the efficacy of Kay repair in a novel ex vivo pulsatile system. Porcine tricuspid valve (TV) (n = 3) was extracted and incorporated into a patient-specific silicon right ventricle (RV) emulating severe FTR, on which Kay repair was subsequently performed. TV area metrics and RV hemodynamic assessment by means of stereo-scopic particle image velocimetry were quantified in both FTR and post-repair conditions. Bicuspidization led to significant increase in cardiac output although the overall increment due to this approach alone was generally small, possibly due to existence of residual TR and the large reduction in TV opening area. Kinetic energy and viscous loss levels were increased post-repair, especially during diastolic filling. Main vortex structures generally maintained post-procedural. However, there was enhanced swirling motion in larger RV domain. Although this might reduce mural-thrombus risk, the relatively more complex vortex phenomenon likely resulted in elevated viscous loss observed and may potentially impact long-term adaptation. The RV hemodynamic alteration after tricuspid repair could be used to predict the success of these future transcatheter solutions.

Particle Image Velocimetry Measurements of the Flow-Diverting Effects of a New Generation of the eCLIPs Implant for the Treatment of Intracranial Bifurcation Aneurysms

“…While it was expected to observe a complex flow in the XZ plane, the out-of-plane behavior of the flow remains ambiguous for future studies. If the out-of-plane velocity and transverse secondary flow development are deemed necessary, stereo-PIV, tomographic PIV [38,39], or three-dimensional phase-contrast MRI can be utilized [40]. These may be employed in future studies to help verify the results presented herein.…”

Mock circulatory loop applications for testing cardiovascular assist devices and in vitro studies

“…During in vitro experiments, flow parameters of pressure and flowrate will be monitored, since these are the physical quantities that directly reflect the working state of CADs. In addition to some specific transducers and probes for the basic measurement, there are various other advanced methods combined with MCL to test CADs, such as cine cameras ( McMillan et al, 1952 ; Dávila et al, 1956 ; Heiliger et al, 1987 ) used in the 1950s to observe valve motion, high-speed cameras ( Lin et al, 2000 ; Linde et al, 2012 ; Suzuki et al, 2012 ; Schlöglhofer et al, 2013 ; Tsuboko et al, 2016 ; Feng et al, 2017 ) used since 2000s, PIV ( Tanné et al, 2010 ; Pelletier et al, 2015 ; Nguyen et al, 2017 ; Nguyen et al, 2019 ; Bonfanti et al, 2020 ; Madukauwa-David et al, 2020 ) and the MRI ( Hattori et al, 2021 ) used in the last decades to study the flow fields inside the organ phantoms of MCL. These advanced measurement methods make it possible to investigate the internal flow field deeply and comprehensively.…”

“…With the patient-specific silicon ventricle model based on computed tomography scanning, MCL can simulate the blood flow that is more similar to the native ventricle. Then, PIV technique can be applied to visualize the flow field inside the ventricle, and the flow information under the influence of PHV motion can be analyzed to guide the PHV design ( Nguyen et al, 2017 ; Nguyen et al, 2019 ). Moreover, medical imaging equipment can also be used with MCL to study hemodynamics.…”

“…Replacing the flexible silicone sacs with patient-specific anatomical ventricle phantoms can provide a more realistic simulation of the human body, which is a common strategy for testing PHV and VAD with MCL. By using those transparent phantoms, MCL can work under methods of flow visualization ( Cassot et al, 1985 ), PIV ( Tanné et al, 2010 ; Nguyen et al, 2017 ; Nguyen et al, 2019 ) and other measurement techniques to perform internal hemodynamic investigations.…”

“…The physical information inside the anatomical phantoms, such as velocity and shear stress, provides inspirations for the CAD design and optimization. Nguyen et al (2017) built the MCL incorporating a patient-specific right ventricle phantom to investigate the hemodynamics under the influence of the valves ( Nguyen et al, 2019 ). Their findings gave clues to the heart valve improvement.…”