scholarly journals Aortic regurgitation after transcatheter aortic valve replacement

2018 ◽  
Vol 4 (1) ◽  
pp. 195-198
Keyword(s):  
Aortic Valve ◽  
Hydrodynamic Performance ◽  
In Vitro Test ◽  
Valve Prosthesis ◽  
Test Setup ◽  
Transcatheter Aortic Valve ◽  
Implantation Depth ◽  
First Results ◽  
Valve Prostheses

AbstractThe assessment of hydrodynamic performance of transcatheter aortic valve prostheses in vitro is essential for the develosepment and approval of novel devices. Therefore, this study aims to investigate the correlation of target implantation depth and paravalvular regurgitation in a controlled in vitro test situation. We designed a test setup with retrograde steady flow conditions measuring paravalvular regurgitation as a function of increasing pressure on the closed valve ranging from 0 mmHg to 200 mmHg. Our future aim is to benchmark different valve prosthesis designs and describe the correlation between target implantation depth, paravalvular regurgitation and prosthesis design aspects. The current study describes the developed test setup, validation experiments as well as first results for a selfexpanding valve prosthesis. The highest regurgitation was measured at an implantation depth of 2 mm. In fact, regurgitation increases from 26.1 ± 8.2 ml/min at 0 mmHg to 1,490.7 ± 182.7 ml/min at 160 mmHg. The slightest regurgitation, however, was measured for an implantation depth of 6 mm ranging from 2.2 ± 0.6 ml/min at 0 mmHg to 605.8 ± 18.9 ml/min at 200 mmHg.

scholarly journals Impact of aortic annulus geometry according to ISO 5840:2019 (draft) on hydrodynamic performance of transcatheter aortic valve prostheses

2020 ◽  
Vol 6 (3) ◽  
pp. 454-457
Author(s):  
Jan Oldenburg ◽  
Sebastian Kaule ◽  
Stefan Siewert ◽  
Klaus-Peter Schmitz ◽  
Michael Stiehm ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Hydrodynamic Performance ◽  
Performance Criteria ◽  
Modular System ◽  
Effective Orifice Area ◽  
In Vitro Test ◽  
Transcatheter Aortic Valve ◽  
Valve Prostheses ◽  
Hydrodynamic Testing

AbstractTo assess the hydrodynamic performance of transcatheter aortic valve prostheses (TAVP), in vitro test using pulse duplicators is required. Test conditions as well as minimum performance criteria are specified in ISO 5840- 3:2013 and ISO 5840-3:2019-draft. In the 2019 published draft, modifications regarding hydrodynamic testing are proposed. Among others, the geometrical configuration of the fixation has changed, with the intention to improve the anatomical representation as well as the comparability of results from different test laboratories. We analyzed the consequences of altered annulus fixations regarding native leaflets as well as a step in the proximal area of the protheses to prevent their migration. The analyses were conducted with regard to the degree of calcification of the annulus ring on hydrodynamic parameters. By using 3D stereolithography printing technology, molds for casting of silicone elastomer of annulus models with and without native leaflets were manufactured. A modular system enabled us to use the same annulus ring to model the degree of calcification as well as different step sizes. We performed in vitro hydrodynamic testing according to ISO 5840-3:2019-draft of a selfexpandable valve prototype with porcine pericardial leaflets by using a commercially available pulse duplicator system. As expected, regurgitation increases with increasing degree of calcification, whereby the use of a step has no influence on the backflow of fluid during diastole. The effective orifice area (EOA) of the valve showed a clear tendency with respect to radial protrusion of the step. The EOA decreased as the radial protrusion increased. We also present a suggestion to prevent migration without affecting the general test results, by using a novel step design. We also found that the novel annulus model with native leaflet drastically reduced the regurgitation.

scholarly journals Impact of aortic root geometry on hydrody-namic performance of transcatheter aortic valve prostheses

2017 ◽  
Vol 3 (2) ◽  
pp. 509-512
Author(s):  
Sebastian Kaule ◽  
Sylvia Pfensig ◽  
Robert Ott ◽  
Stefan Siewert ◽  
Niels Grabow ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Root ◽  
Water Soluble ◽  
Hydrodynamic Performance ◽  
Worst Case ◽  
Testing Environment ◽  
Transcatheter Aortic Valve ◽  
Valve Prostheses ◽  
Hydrodynamic Testing

AbstractAssessment of hydrodynamic performance of transcatheter aortic valve prostheses (TAVP) in vitro is es-sentially in the fields of development and approval of novel implants. For the prediction of clinical performance, in vitro testing of TAVP allows for benchmarking of different devic-es, likewise. In addition to the implant itself, also the testing environment has a crucial influence on leaflet dynamics and quantitative test results like effective orifice area (EOA) or aortic regurgitation.Therefore, within the current study we developed simpli-fied physiological and pathophysiological vessel models of the aortic root as a tool for in vitro hydrodynamic testing of TAVP in idealized and worst case conditions. We used 3D printing and silicone cast molding for manufacturing of aortic root models with variable degree of stenosis. Design of aortic roots with normal, mild and severe stenosis was developed according to Reul et al. For manufacturing of tripartite cast-ing molds, a 3D printer was used. Both outer mold parts and the mold core were manufactured from polylactide filament and water soluble polyvinylalcohol filament, respectively. In vitro hydrodynamic performance testing of an exemplary commercially available TAVP implanted in different aortic root models was conducted according to DIN EN ISO 5840-3:2013, using a pulse duplicator system. Manufactured aortic root models were highly transparent, dimensionally stable and therefore suitable for hydrodynamic testing of TAVP. Both, EOA and regurgitant fraction in-creased with increasing degree of stenosis from 1.6 ± 0.1 cm2 to 1.8 ± 0.1 cm2 and 8.6 ± 6.5% to 20.2 ± 4.2% (n = 30 cy-cles), respectively.We successfully developed a testing environment ena-bling sophisticated evaluation of hydrodynamic performance of TAVR in pathophysiological worst case conditions.

scholarly journals Hemodynamic influence of design parameters of novel venous valve prostheses

2018 ◽  
Vol 4 (1) ◽  
pp. 149-151
Author(s):  
Michael Stiehm ◽  
Stefanie Kohse ◽  
Kerstin Schümann ◽  
Sebastian Kaule ◽  
Stefan Siewert ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Lower Limbs ◽  
Hydrodynamic Performance ◽  
Design Parameters ◽  
Effective Orifice Area ◽  
Valve Prosthesis ◽  
Venous Valve ◽  
Orifice Area ◽  
Valve Prostheses

AbstractVenous ulcers of the lower limbs are one clinical manifestation of chronic venous insufficiency. Currently, there is no venous valve prosthesis available. This study presents novel venous valve prostheses made of threedimensional electrospun fibrous nonwoven leaflets. The aim of this study was to prove the feasibility of the manufacturing process as well as to investigate design features of the venous valve prostheses from a hemodynamic point of view. An adapted pulse duplicator system (ViVitrolabs, Victoria, BC, CA) was used for characterization of the hydrodynamic performance. For eight different venous valve prototypes flow rate, effective orifice area and regurgitation fraction was investigated in vitro. In particular, tricusp valve designs showed an up to 40% higher effective orifice area as well as 15% higher maximum flowrate compared to bicusp valve designs. However, the regurgitation fraction of the bicusp valve designs is up to 86% lower compared to tricusp valve. Additionally, the hemodynamic performance of the tricuspid valves showed a high sensitivity regarding the leaflet length. Bicuspid valves are less sensitive to changes of design parameters, more sufficient and therefore highly reliable.

scholarly journals Fluid-structure interaction of heart valve dynamics in comparison to finite-element analysis

2018 ◽  
Vol 4 (1) ◽  
pp. 259-262 ◽  
Author(s):  
Finja Borowski ◽  
Michael Sämann ◽  
Sylvia Pfensig ◽  
Carolin Wüstenhagen ◽  
Robert Ott ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Heart Valve ◽  
Elastic Behavior ◽  
Valve Prosthesis ◽  
Arbitrary Lagrangian Eulerian ◽  
Element Analysis ◽  
Valve Dynamics ◽  
Valve Opening ◽  
Valve Prostheses

AbstractAn established therapy for aortic valve stenosis and insufficiency is the transcatheter aortic valve replacement. By means of numerical simulation the valve dynamics can be investigated to improve the valve prostheses performance. This study examines the influence of the hemodynamic properties on the valve dynamics utilizing fluidstructure interaction (FSI) compared with results of finiteelement analysis (FEA). FEA and FSI were conducted using a previously published aortic valve model combined with a new developed model of the aortic root. Boundary conditions for a physiological pressurization were based on measurements of ventricular and aortic pressure from in vitro hydrodynamic studies of a commercially available heart valve prosthesis using a pulse duplicator system. A linear elastic behavior was assumed for leaflet material properties and blood was specified as a homogeneous, Newtonian incompressible fluid. The type of fluid domain discretization can be described with an arbitrary Lagrangian-Eulerian formulation. Comparison of significant points of time and the leaflet opening area were used to investigate the valve opening behavior of both analyses. Numerical results show that total valve opening modelled by FEA is faster compared to FSI by a factor of 5. In conclusion the inertia of the fluid, which surrounds the valve leaflets, has an important influence on leaflet deformation. Therefore, fluid dynamics should not be neglected in numerical analysis of heart valve prostheses.

scholarly journals Does transcatheter aortic valve alignment matter?

Open Heart ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. e001132 ◽  
Author(s):  
Jacob Andrew Salmonsmith ◽  
Andrea Ducci ◽  
Gaetano Burriesci
Keyword(s):  
Aortic Valve ◽  
Aortic Root ◽  
Performance Data ◽  
Root Anatomy ◽  
Hydrodynamic Performance ◽  
Transcatheter Aortic Valve ◽  
Flow Stagnation ◽  
Image Velocimetry ◽  
Valve Function

ObjectiveThis study investigates the effect of transcatheter aortic valve (TAV) angular alignment on the postprocedure haemodynamics. TAV implantation has emerged as an effective alternative to surgery when treating valve dysfunction. However, the benefit of avoiding surgery is paid back by the inability to remove the native diseased leaflets and accurately position the device in relation to the aortic root, and the literature has shown the root anatomy and substitute position can play an essential role on valve function.MethodsA commercial TAV was placed in a silicone mock aortic root in vitro, including mock native leaflets, and either aligned commissure-to-commissure or in maximum misalignment. Haemodynamic performance data at various stroke volumes were measured, and Particle Image Velocimetry analysis was performed at a typical stroke volume for rest conditions. The two configurations were also studied without mock native leaflets, for comparison with previous in vitro studies.ResultsHaemodynamic performance data were similar for all configurations. However, imaging analysis indicated that valve misalignment resulted in the central jet flow not extending to the root wall in the native commissures’ vicinity, replaced by a low shear flow, and a reduction of upper sinus flow of 40%, increasing flow stagnation in the sinus.ConclusionsTAV misalignment did not result in a significant change in valve hydrodynamic performance, but determined some change in the fluid flow patterns, which may promote pathological scenarios, such as increased thrombogenicity of blood flow within the sinuses of Valsalva, and plaque formation around the lumen of the sinotubular junction.

A Semi-Stented and Chorded Mitral Valve Prosthesis: Design and Method of Chordal Setting and In Vitro Testing

2018 ◽  
Author(s):  
R. Kotzé ◽  
L. Deorsola
Keyword(s):  
Mitral Valve ◽  
Mitral Annulus ◽  
Hydrodynamic Performance ◽  
Valve Prosthesis ◽  
Performance Requirements ◽  
Mitral Valve Prosthesis ◽  
Valve Prostheses ◽  
Minimum Performance ◽  
Ventricular Dynamics

Mitral subvalvular apparatus plays an important role in mitral and ventricular dynamics by preserving annuloventricular continuity, known to be fundamental for ventricular function. While some proposed mitral valve prostheses designs do attempt to account for this relationship by using papillary flaps, they are not adjustable and do not mimic the native saddle shaped mitral annulus. Unfortunately, these designs are not versatile as their papillary flap lengths cannot be altered and the prostheses are unsuitable for percutaneous implantation. We address these issues through the design of a novel semistented and chorded mitral valve that better mimics the native mitral annulus, leaflets and chordae function and can be made from off-the-shelf biomaterials with the potential to be implanted percutaneously. We also propose a novel and reliable method to set the chordal lengths individually. Finally, we demonstrate the hydrodynamic performance of the valve, showing that it meets the minimum performance requirements stipulated by the international standard ISO 5840-3:2013.

scholarly journals Implantation of three transcatheter aortic valves for embolization of two valves caused by under-expansion: a case report

2020 ◽  
Author(s):  
Masaki Tsuda ◽  
Ryu Shutta ◽  
Masami Nishino ◽  
Jun Tanouchi
Keyword(s):  
Aortic Valve ◽  
Balloon Dilation ◽  
In Vitro Test ◽  
Aortic Valves ◽  
Transcatheter Aortic Valve ◽  
Case Summary ◽  
Vitro Test ◽  
Valve Implantation

Abstract Background Transcatheter aortic valve embolization is one of the serious complications of transcatheter aortic valve implantation (TAVI). We present a case of TAVI that needed implantation of three transcatheter aortic valves owing to the embolization of two self-expandable valves (SEVs). Case summary An 88-year-old woman underwent TAVI using a 26-mm SEV. After valve deployment, the SEV embolized to the ascending aorta during the removal of the delivery system (DS) of the SEV (DS-SEV) from the SEV. An additional SEV was implanted, which also embolized upwards. Multi-directional fluoroscopy revealed extreme under-expansion of the second SEV, which caused valve embolization due to catching of the DS-SEVs in the SEVs. Finally, a 23-mm balloon-expandable valve was successfully implanted, which was also under expanded on fluoroscopic assessment. The patient was stable without sequelae at the 1-month follow-up. Discussion Pre-procedurally predicting SEV under-expansions was difficult because pre-procedural computed tomography revealed no massive calcification on the aortic valve, and fluoroscopy indicated adequate expansion of the SEVs at the angle where the valves were deployed. We verified the possibility of catching of a DS-SEV in an under-expanded SEV in an in vitro test, which showed that the DS-SEV was caught in the extremely under-expanded SEV. Furthermore, balloon dilation might release the catch of the DS-SEV by changing the DS-SEV position. Therefore, we recommend performing multi-directional fluoroscopy to evaluate SEV expansion before DS-SEV removal from an SEV. Furthermore, if catching of a DS-SEV occurs, balloon dilation might be useful for releasing the catch and safely removing the DS-SEV.

scholarly journals Influence of leaflet geometry on hydrodynamic performance of transcatheter aortic valve prostheses

2019 ◽  
Vol 5 (1) ◽  
pp. 473-475
Author(s):  
Kaule Sebastian ◽  
Pfensig Sylvia ◽  
Siewert Stefan ◽  
Sylvia Pfensig ◽  
Stefan Siewert ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Material Selection ◽  
Aortic Pressure ◽  
Hydrodynamic Performance ◽  
Closing Volume ◽  
Electrospinning Technique ◽  
Transcatheter Aortic Valve ◽  
A Value ◽  
Risk Patients ◽  
Valve Prostheses

AbstractThe implantation of transcatheter aortic valve prostheses (TAVP) for therapy of aortic valve stenosis shows more and more clinically non-inferiority results compared to surgical valve replacement in intermediate and low risk patients. Commonly clinically used TAVP are manufactured from chemically fixed xenograft leaflet material, e.g. bovine or porcine pericardium. While the clinical use of TAVP currently extends, challenges concerning valve durability and leaflet calcification have to be addressed. In this regard, artificial leaflet materials represent a promising option for a next generation of TAVP. As a first step for the development of TAVP from polymeric nonwoven, the aim of this study was to determine the influence of leaflet geometry on hydrodynamic performance of TAVP prototypes. Based on a parametric model of the valve leaflets, we varied the curvature of the belly line forming the leaflet coaptation area from an initial, quite concave, leaflet geometry with a value of 0.5° to an almost straight geometry for the leaflets with a value 0.15°. Manufacturing of TAVP prototypes was conducted by means of electrospinning technique with a polycarbonate based silicone elastomer. Hydrodynamic characterization according to ISO 5840-3 standards was performed using a pulse duplicator system with a heart rate of 70 BPM, systolic duration of 35%, mean aortic pressure of 100 mmHg and a stroke volume of 96 ml. Cardiac output as well as mean transaortic pressure gradient, closing volume, leakage volume and regurgitation were measured to compare the different leaflet geometries. To summarize, the curvature of the leaflets’ belly has a crucial impact on TAVP hydrodynamics under physiological test conditions. In particular, the opening and closing behavior is strongly influenced by a steeper curvature leading to larger closing volumes and higher regurgitant fractions. Further studies are planned to identify an optimum with respect to leaflet material selection, leaflet geometry and hydrodynamic properties of TAVP.

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