Impact of patient-specific morphologies on sinus flow stasis in transcatheter aortic valve replacement: An in vitro study

Hatoum, Hoda; Dollery, Jennifer; Lilly, Scott; Crestanello, Juan A.; Dasi, Lakshmi Prasad

doi:10.1016/j.jtcvs.2018.05.086

Cited by 53 publications

(53 citation statements)

References 40 publications

(57 reference statements)

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“…The development of thrombus post-TAVR is an intriguing adverse effect given the diversity of reasons that may contribute to it. It is clear that flow stasis is what aids the formation of thrombus and that it is dependent on a variety of factors such as coronary flow 16, 22, 40 , valve type 13, 16 , valve positioning 22 etc. Interestingly however, given that most leaflet thrombosis occurs on one or two leaflets only, it is intriguing to investigate the asymmetry in flow stasis due to potential tilt in the axis of the TAV.…”

Section: Discussionmentioning

confidence: 99%

“…Viscous shear stress field was evaluated consistently with Hatoum et al 12, 13, 18, 19, 22, 23 and Moore et al 21 .…”

Section: Methodsmentioning

confidence: 99%

“…Velocity vectors were calculated using adaptive cross-correlation algorithms. Further details of PIV measurements can be found in Hatoum et al 12, 13, 16–20 .…”

Section: Methodsmentioning

confidence: 99%

“…Ideally good washout is associated with a high percentage of particles exiting over a minimum number of cardiac cycles. To quantify sinus washout curves, first particle tracking was performed similar to other studies 13, 22, 24–26 . Briefly, particles were seeded as a uniform grid of 1mm x 1mm cell size over the sinus region at the beginning of the cardiac cycle.…”

Section: Methodsmentioning

confidence: 99%

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Sinus Hemodynamics Variation with Tilted Transcatheter Aortic Valve Deployments

et al. 2018

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Leaflet thrombosis is a complication associated with transcatheter aortic valve (TAV) replacement (TAVR) correlated with sinus flow stasis. Sinus hemodynamics are important because they dictate shear stress and washout necessary to avoid stasis on TAV leaflets. Sinus flow is controlled by TAV axial deployment position but little is known regarding TAV axis misalignment effect. This study aims to elucidate TAV angular misalignment with respect to aortic root axis effect on sinus flow stasis potentially leading to leaflet thrombosis. Sinus hemodynamics were assessed in vitro using particle-image velocimetry in three different angular misalignments with respect to aorta axis: untilted, tilted away from the sinus and tilted towards sinus. A 26 mm Edwards SAPIEN3 was implanted in a 3D printed model of an anatomically realistic aortic root. TAV hemodynamics, sinus vortex tracking, leaflet shear stress probability density functions, and sinus blood time to washout were calculated. While pressure gradients differed insignificantly, blood velocity and vorticity decreased significantly in both tilted cases sinuses. Shear stress probability near the leaflet decreases with tilt indicating stasis. TAV tilted away from the sinus is the most unfavorable scenario with poor washout. TAV axial misalignment adds to factors list that could influence leaflet thrombosis risk through modifying sinus hemodynamics and washout.

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Section: Discussionmentioning

confidence: 99%

“…Viscous shear stress field was evaluated consistently with Hatoum et al 12, 13, 18, 19, 22, 23 and Moore et al 21 .…”

Section: Methodsmentioning

confidence: 99%

“…Velocity vectors were calculated using adaptive cross-correlation algorithms. Further details of PIV measurements can be found in Hatoum et al 12, 13, 16–20 .…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Sinus Hemodynamics Variation with Tilted Transcatheter Aortic Valve Deployments

et al. 2018

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“…13,14 We therefore complemented the hydrodynamic assessment by testing the valves under more realistic deployed TAVR conditions in a patient-specific anatomical model of an AS patient with an advanced stage CAVD, using the Replicator pulse duplicator system (Vascular Simulations LLC, Stony Brook, NY, USA). 30 Importantly, the setup and testing conditions performed in this section were also compliant with ISO guidelines.…”

Section: Methodsmentioning

confidence: 99%

Novel Polymeric Valve for Transcatheter Aortic Valve Replacement Applications: In Vitro Hemodynamic Study

et al. 2018

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Transcatheter aortic valve replacement (TAVR) is a minimally-invasive approach for treating severe aortic stenosis. All clinically-used TAVR valves to date utilize chemically-fixed xenograft as the leaflet material. Inherent limitation of the tissue (e.g., calcific degeneration) motivates the search for alternative leaflet material. Here we introduce a novel polymeric TAVR valve that was designed to address the limitations of tissue-valves. In this study, we experimentally evaluated the hemodynamic performance of the valve and compared its performance to clinically-used valves: a gold standard surgical tissue valve, and a TAVR valve. Our comparative testing protocols included: (i) baseline hydrodynamics (ISO:5840-3), (ii) complementary patient-specific hydrodynamics in a dedicated system, and (iii) thrombogenicity. The patient-specific testing system facilitated comparing TAVR valves performance under more realistic conditions. Baseline hydrodynamics results at CO 4-7 L/min showed superior effective orifice area (EOA) for the polymer valve, most-notably as compared to the reference TAVR valve. Regurgitation fraction was higher in the polymeric valve, but within the ISO minimum requirements. Thrombogenicity trends followed the EOA results with the polymeric valve being the least thrombogenic, and clinical TAVR being the most. Hemodynamic-wise, the results strongly indicate that our polymeric TAVR valve can outperform tissue valves.

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