scholarly journals In Vitro Study of a Stentless Aortic Bioprosthesis Made of Bacterial Cellulose

2020 ◽  
Vol 11 (6) ◽  
pp. 646-654
Author(s):  
Kinga Dawidowska ◽  
Piotr Siondalski ◽  
Magdalena Kołaczkowska
Keyword(s):  
Aortic Valve ◽  
Bacterial Cellulose ◽  
Flow Resistance ◽  
Valve Prosthesis ◽  
Mean Flow ◽  
Basic Model ◽  
Aortic Valve Prosthesis ◽  
Valve Opening ◽  
The Mean

Abstract Purpose The paper present findings from an in vitro experimental study of a stentless human aortic bioprosthesis (HAB) made of bacterial cellulose (BC). Three variants of the basic model were designed and tested to identify the valve prosthesis with the best performance parameters. The modified models were made of BC, and the basic model of pericardium. Methods Each model (named V1, V2 and V3) was implanted into a 90 mm porcine aorta. Effective Orifice Area (EOA), rapid valve opening time (RVOT) and rapid valve closing time (RVCT) were determined. The flow resistance of each bioprosthesis model during the simulated heart systole, i.e. for the mean differential pressure (ΔP) at the time of full valve opening was measured. All experimental specimens were exposed to a mean blood pressure (MBP) of 90.5 ± 2.3 mmHg. Results The V3 model demonstrated the best performance. The index defining the maximum opening of the bioprosthesis during systole for models V1, V2 and V3 was 2.67 ± 0.59, 2.04 ± 0.23 and 2.85 ± 0.59 cm2, respectively. The mean flow rate through the V3 valve was 5.7 ± 1, 6.9 ± 0.7 and 8.9 ± 1.4 l/min for stroke volume (SV) of 65, 90 and 110 mL, respectively. The phase of immediate opening and closure for models V1, V2 and V3 was 8, 7 and 5% of the cycle duration, respectively. The mean flow resistance of the models was: 4.07 ± 2.1, 4.28 ± 2.51 and 5.6 ± 2.32 mmHg. Conclusions The V3 model of the aortic valve prosthesis is the most effective. In vivo tests using BC as a structural material for this model are recommended. The response time of the V3 model to changed work conditions is comparable to that of a healthy human heart. The model functions as an aortic valve prosthesis in in vitro conditions.

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 Numerical and experimental justification of transcatheter aortic valve prosthesis design

2021 ◽  
Vol 23 (2) ◽  
pp. 95-103
Author(s):  
E. A. Ovcharenko ◽  
K. U. Klyshnikov ◽  
A. A. Shilov ◽  
N. A. Scheglova ◽  
T. V. Glushkova ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Ethylene Glycol ◽  
Computer Models ◽  
Diglycidyl Ether ◽  
Effective Orifice Area ◽  
Radial Compression ◽  
Valve Prosthesis ◽  
Transcatheter Aortic Valve ◽  
Aortic Valve Prosthesis ◽  
The Mean

Objective: to justify the design of a self-expanding transcatheter aortic valve prosthesis based on a biomaterial stabilized with ethylene glycol diglycidyl ether using numerical simulation and a series of field experiments with working prototypes to determine the consistency of the proposed design solutions.Material and methods. Numerical computer models of a developed aortic valve prosthesis intended for transcatheter implantation, as well as prototypes of the most promising concepts for a series of field tests, were used in the work. Computer 3D models were subjected to numerical analysis in the Abaqus/CAE environment (Dassault Systemes, France) based on the finite element method with iterative design optimization and repeated numerical experiments. Physical prototypes of the transcatheter prosthesis were subjected to a series of mechanical tests for axial and radial compression, as well as tests on a Vivitro hydrodynamic stand (Vivitro Labs, Canada) under simulated normal flow. All studies were carried out in a comparative aspect with a similar transcatheter aortic valve prosthesis (control), the CoreValve™ bioprosthesis (Medtronic, Inc., USA).Results. Computer simulation demonstrates the stress-strain state values that do not significantly exceed the critical levels (628 and 756 MPa versus the threshold value 1080 MPa) for two basic concepts of support frames. The fatigue strength based on the calculation of the mean and alternating stresses corresponding to normo- and hypertensive states based on the Goodman diagrams, did not reveal any evidence that the threshold values (destruction area after 200 million cycles) were exceeded. The hydrodynamic characteristics of working prototypes made on the basis of computer models correspond to the testing data of CoreValve™ clinical bioprosthesis: the effective orifice area was 1.97 cm2, the mean transprosthetic gradient was 8.9 mm Hg, the regurgitant volume was 2.2–4.1 mL per cycle depending on the prototype model.Conclusion. Generally, experiments carried out showed the consistency of the concepts, including from the point of view of implementation of the leaflet apparatus based on xenogeneic tissues treated with ethylene glycol diglycidyl ether.

scholarly journals In vitro evaluation of aortic valve prosthesis in a novel valved conduit with pseudosinuses of Valsalva

2005 ◽  
Vol 130 (4) ◽  
pp. 1016-1021 ◽  
Author(s):  
Ruggero De Paulis ◽  
Christoph Schmitz ◽  
Raffaele Scaffa ◽  
Paolo Nardi ◽  
Luigi Chiariello ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Valve Prosthesis ◽  
In Vitro Evaluation ◽  
Aortic Valve Prosthesis ◽  
Valved Conduit

RF59 PERCEVAL SUTURELESS AORTIC VALVE PROSTHESIS

2018 ◽  
Vol 19 ◽  
pp. e44
Author(s):  
E. Mikus ◽  
M. Pagliaro ◽  
S. Calvi ◽  
M. Panzavolta ◽  
E. Ramoni ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Valve Prosthesis ◽  
Aortic Valve Prosthesis

Passing a Mechanical Aortic Valve With a Short Tip Dilator to Facilitate Aortic Arch Endovascular Branched Repair

2021 ◽  
pp. 152660282110025
Author(s):  
Nikolaos Konstantinou ◽  
Sven Peterss ◽  
Jan Stana ◽  
Barbara Rantner ◽  
Ramin Banafsche ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Arch ◽  
Stent Graft ◽  
Mechanical Valve ◽  
Valve Prosthesis ◽  
Proper Position ◽  
Mechanical Aortic Valve ◽  
Aortic Replacement ◽  
Custom Made ◽  
Aortic Valve Prosthesis

Purpose To present a novel technique to successfully cross a mechanical aortic valve prosthesis. Technique A 55-year-old female patient with genetically verified Marfan syndrome presented with a 5-cm anastomotic aneurysm of the proximal aortic arch after previous ascending aortic replacement due to a type A aortic dissection in 2007. The patient also underwent mechanical aortic valve replacement in 1991. A 3-stage hybrid repair was planned. The first 2 steps included debranching of the supra-aortic vessels. In the third procedure, a custom-made double branched endovascular stent-graft with a short 35-mm introducer tip was implanted. The mechanical valve was passed with the tip of the dilator on the lateral site of the leaflet, without destructing the valve and with only mild symptoms of aortic insufficiency, as one leaflet continued to work. This allowed the implantation of the stent-graft directly distally of the coronary arteries. Postoperative computed tomography angiography showed no endoleaks and patent coronary and supra-aortic vessels. Conclusion Passing a mechanical aortic valve prosthesis at the proper position is feasible and allows adequate endovascular treatment in complex arch anatomy. However, caution should be taken during positioning of the endovascular graft as the tip may potentially damage the valve prosthesis.

A New Generation of Aortic Valve Prosthesis: Design, Manufacture and Hydrodynamic Assessment

2012 ◽  
Author(s):  
Benyamin Rahmani ◽  
Hossein Ghanbari ◽  
Spyridon Tzamtzis ◽  
Gaetano Burriesci ◽  
Alexander M. Seifalian
Keyword(s):  
Aortic Valve ◽  
Heart Valves ◽  
Artery Bypass ◽  
Polymeric Materials ◽  
Valve Prosthesis ◽  
Nanocomposite Polymer ◽  
Cardiac Procedure ◽  
Aortic Valve Prosthesis ◽  
Suboptimal Design ◽  
New Generation

Aortic valve replacement (AVR) is the second most common cardiac procedure after coronary artery bypass grafting, accounting for more than 200,000 transplantations annually worldwide [1]. Currently available mechanical and bioprosthetic heart valve replacements are not ideal as they are associated with relevant complications. The tri-leaflet polymeric heart valves (PHVs) have been widely investigated as possible alternative to these substitutes. However, the clinical application of PHVs has been limited by their suboptimal design and poor durability of available polymeric materials. This study presents a new concept of surgical aortic valve using a novel nanocomposite polymer.

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