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 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 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.

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