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 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 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 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.

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 Hydrodynamic performance of a novel suturelessprosthetic aortic valve

2020 ◽  
Vol 22 (2) ◽  
pp. 117-124
Author(s):  
K. Yu. Klyshnikov ◽  
E. A. Ovcharenko ◽  
Yu. A. Kudryavtseva ◽  
L. S. Barbarash
Keyword(s):  
Aortic Valve ◽  
Prosthetic Heart Valve ◽  
Hydrodynamic Performance ◽  
Hydrodynamic Characteristics ◽  
Effective Orifice Area ◽  
Orifice Area ◽  
Comparative Aspect ◽  
Hydrodynamic Study ◽  
Valve In Valve

The aim of the study was an in vitro hydrodynamic study of the developed prosthetic heart valve of the second generation, designed to carry out an implantation using «valve-in-valve» method. Material and methods. Prototypes of the developed prosthesis were studied under simulated physiological conditions of the heart using a Vivitro Labs pulse duplicator (Canada) in a comparative aspect with «UniLine» clinical commercial aortic valve bioprosthesis (Russia). Samples were tested by simulating sutureless implantation procedure. Results. The developed valves showed satisfactory hydrodynamic characteristics – for all cases of «implantation» from the position of the average trans-prosthetic gradient (6.1–11.1 mm Hg) and the effective orifice area (1.60–1.81 cm2 ). The analysis of the regurgitation fraction allowed us to determine the optimal sizes for implantation using «valvein-valve» method, which subsequently will form the basis of sizing guidelines for size selection. A qualitative analysis of the leaflet’s work demonstrated the presence of slight asymmetry for a number of prostheses – in case of mismatch of sizes when simulating «valve-in-valve» procedure. Conclusion. The tests demonstrate the viability of the developed design from the standpoint of hydrodynamic efficiency and determines the basic rules of selecting a prosthesis for reimplantation relative to the primary valve.

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.

scholarly journals Effective Orifice Area of Balloon-Expandable and Self-Expandable Transcatheter Aortic Valve Prostheses: An Echo Doppler Comparative Study

2021 ◽  
Vol 10 (2) ◽  
pp. 186
Author(s):  
Mohamad Kanso ◽  
Marion Kibler ◽  
Sebastien Hess ◽  
Jérome Rischner ◽  
Philoktimon Plastaras ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Heart Valves ◽  
Severe Aortic Stenosis ◽  
Published Data ◽  
Effective Orifice Area ◽  
Orifice Area ◽  
Transcatheter Aortic Valve ◽  
Valve Prostheses ◽  
Valve Implantation ◽  
New Generation

Published data on the size-specific effective orifice area (EOA) of transcatheter heart valves (THVs) remain scarce. Here, we sought to investigate the intra-individual changes in EOA and mean transvalvular aortic gradient (MG) of the Sapien 3 (S3), CoreValve (CV), and Evolut R (EVR) prostheses both at short-term and at 1-year follow-up. The study sample consisted of 260 consecutive patients with severe aortic stenosis who underwent transcatheter aortic valve implantation (TAVI). EOAs and MGs were measured with Doppler echocardiography for the following prostheses: S3 23 mm (n = 74; 28.5%), S3 26 mm (n = 67; 25.8%), S3 29 mm (n = 20; 7.7%), CV 23 mm (n = 2; 0.8%), CV 26 mm (n = 15; 5.8%), CV 29 mm (n = 24; 9.2%), CV 31 mm (n = 9; 3.5%), EVR 26 mm (n = 22; 8.5%), and EVR 29 mm (n = 27; 10.4%). Values were obtained at discharge, 1 month, 6 months, and 1 year from implantation. At discharge, EOAs were larger and MGs lower for larger-size prostheses, regardless of being balloon-expandable or self-expandable. In patients with small aortic annulus size, the hemodynamic performances of CV and EVR prostheses were superior to those of S3. However, we did not observe significant differences in terms of all-cause mortality according to THV type or size. Both balloon-expandable and self-expandable new-generation THVs show excellent hemodynamic performances without evidence of very early valve degeneration.

scholarly journals The Usefulness of [18F]F-Fluorodeoxyglucose and [18F]F-Sodium Fluoride Positron Emission Tomography Imaging in the Assessment of Early-Stage Aortic Valve Degeneration after Transcatheter Aortic Valve Implantation (TAVI)—Protocol Description and Preliminary Results

2021 ◽  
Vol 10 (3) ◽  
pp. 431
Author(s):  
Danuta Sorysz ◽  
Rafał Januszek ◽  
Anna Sowa-Staszczak ◽  
Anna Grochowska ◽  
Marta Opalińska ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Emission Tomography ◽  
Effective Orifice Area ◽  
Orifice Area ◽  
Transcatheter Aortic Valve ◽  
Positron Emission ◽  
Pet Ct ◽  
Transvalvular Gradient ◽  
Valve Implantation

Transcatheter aortic valve implantation (TAVI) is now a well-established treatment for severe aortic stenosis. As the number of procedures and indications increase, the age of patients decreases. However, their durability and factors accelerating the process of degeneration are not well-known. The aim of the study was to verify the possibility of using [18F]F-sodium fluoride ([18F]F-NaF) and [18F]F-fluorodeoxyglucose ([18F]F-FDG) positron emission tomography/computed tomography (PET/CT) in assessing the intensity of TAVI valve degenerative processes. In 73 TAVI patients, transthoracic echocardiography (TTE) at initial (before TAVI), baseline (after TAVI), and during follow-up, as well as transesophageal echocardiography (TEE) and PET/CT, were performed using [18F]F-NaF and [18F]F-FDG at the six-month follow-up (FU) visit as a part of a two-year FU period. The morphology of TAVI valve leaflets were assessed in TEE, transvalvular gradients and effective orifice area (EOA) in TTE. Calcium scores and PET tracer activity were counted. We assessed the relationship between [18F]F-NaF and [18F]F-FDG PET/CT uptake at the 6 = month FU with selected indices e.g.,: transvalvular gradient, valve type, EOA and insufficiency grade at following time points after the TAVI procedure. We present the preliminary PET/CT ([18F]F-NaF, [18F]F-FDG) results at the six-month follow-up period as are part of an ongoing study, which will last two years FU. We enrolled 73 TAVI patients with the mean age of 82.49 ± 7.11 years. A significant decrease in transvalvular gradient and increase of effective orifice area and left ventricle ejection fraction were observed. At six months, FU valve thrombosis was diagnosed in four patients, while 7.6% of patients refused planned controls due to the COVID-19 pandemic. We noticed significant correlations between valve types, EOA and transaortic valve gradients, as well as [18F]F-NaF and [18F]F-FDG uptake in PET/CT. PET/CT imaging with the use of [18F]F-FDG and [18F]F-NaF is intended to be feasible, and it practically allows the standardized uptake value (SUV) to differentiate the area containing the TAVI leaflets from the SUV directly adjacent to the ring calcifications and the calcified native leaflets. This could become the seed for future detection and evaluation capabilities regarding the progression of even early degenerative lesions to the TAVI valve, expressed as local leaflet inflammation and microcalcifications.

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