A novel trileaflet mechanical heart valve: first in vitro results

Schubert, Kathrin; Schaller, Tim; Stojenthin, Elisabeth; Stephan, Christian; Sievers, Hans‐Hinrich; Scharfschwerdt, Michael

doi:10.1093/icvts/ivy337

Cited by 10 publications

(7 citation statements)

References 12 publications

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“…The mean transvalvular pressure gradient over time was low (<6 mm Hg) in this study, comparable to the in vitro data for this valve. 3 These results are favorable, particularly because the valve size was only 21 mm and the weight of the animals increased, with the expectation of a higher gradient. Most likely the design of the leaflets, imitating flying wings, along with the confusor/diffusor shape of the ring, had positive effects on undisturbed flow, reducing flow resistance.…”

Section: Discussionmentioning

confidence: 98%

“…The novel mechanical prosthesis consists of 3 leaflets and is described in detail elsewhere. 3 , 4 In brief, the housing is made of medical-grade titanium-aluminium-vanadium alloy (TiAl6V4), a standard material for medical devices because of the good biological and hematologic properties. The leaflets are manufactured from poly-ether-ether-ketone, which has also good biological properties and allows for manufacturing of varying shapes and sizes.…”

Section: Methodsmentioning

confidence: 99%

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Aortic valve replacement in sheep with a novel trileaflet mechanical heart valve prosthesis without anticoagulation

et al. 2021

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Background: Even after decades of intensive research, an ideal heart valve prosthesis remains elusive. Shortcomings of conventional devices include reduced durability of bioprostheses and the thrombogenicity of mechanical substitutes, necessitating anticoagulation and resulting in imperfect hemodynamics. Here we present in vivo results of a novel mechanical heart valve prosthesis aiming for freedom from anticoagulation.Methods: Four female sheep had their aortic valves replaced using the novel mechanical heart valve (size 21 mm), with no postoperative anticoagulation treatment. This trileaflet heart valve was designed with the pivots in the systolic central flow. Hemodynamics, biochemistry, hematology, and macroscopy and microscopy were studied at 90 days in 2 sheep and at 1 year in the other 2 sheep.Results: Mean (<6 mm Hg) and peak (<10 mm Hg) aortic transvalvular gradients remained low during the study period. Aortic regurgitation was trivial, and central traces were only rarely observed. The rate of thrombotic events was very low, with none macroscopically and microscopically visible thrombotic material on the device. Biochemistry and hemotology were unchanged without hemolysis. In 3 sheep, the fibrous pannus and mitral leaflet were partially folded over the edge of the annular body. Apart from organic/inorganic deposits on the leaflets after 1 year, the ultrastructurally evaluated leaflets were similar to those of nonimplanted controls. Conclusions:The preliminary in vivo results of this novel anticoagulation-free aortic mechanical heart valve are promising with excellent hemodynamics and a very low risk of thrombotic events. (JTCVS Open 2021;7:76-88) Novel trileaflet mechanical heart valve explanted after 375 days in a sheep model.

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Section: Discussionmentioning

confidence: 98%

Section: Methodsmentioning

confidence: 99%

Aortic valve replacement in sheep with a novel trileaflet mechanical heart valve prosthesis without anticoagulation

et al. 2021

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“…An alternative, although more expensive, might be ex vivo modelling [31]. Such a methodology was applied in the study of a novel trilea et valve [15,32]. The authors mounted the valve in a pulse duplicator that simulated the physiological system and studied, among others, clot formation.…”

Section: Discussionmentioning

confidence: 99%

Comparative analyses of blood flow through mechanical trileaflet and bileaflet aortic valves

Pawlikowski¹,

Nieroda²

2022

Acta Bioeng Biomech

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Purpose: The primary aim of the present study was to compare the bileaflet and trileaflet aortic valves’ performance during uniform blood flow model and boundary conditions. The secondary aim of the study was to determine the effect of Newtonian/non-Newtonian fluid flow assumption on blood flow directly behind the trileaflet valve. Methods: The geometrical model of the whole system consist of the left ventricle, fragment of the aorta and mechanical valves. A representation of pulsatile flow was obtained by measuring blood flow velocity (Doppler ultrasound examination). We have assumed turbulent blood flow. We considered two blood models, Newtonian and non-Newtonian (Carreau model). The valves’ performance was assessed using the reduced stress in the valves, the shear stress in the aortic wall, flow velocity field and the effective orifice area. Results: The maximum von Mises stress for the bileaflet valve leaflets was 0.3 MPa and for the trileaflet valve – 0.06 MPa. The maximum flow velocity for the bileaflet valve was 4.52 m/s for 40° and for the trileaflet valve – 5.74 m/s. Higher shear stress was present in the bileaflet (151.5 Pa) than for the trileaflet valve (49.64 Pa). Conclusions: The results indicate that central blood jet for the trileaflet valve contributes to more physiological blood flow and decreases the risk of haemolysis. The central flow minimises the risk of leaflet dislocation. In addition, lower stresses extend the durability of the valve. However, the trileaflet valve geometry has also disadvantages, for instance, small peripheral streams or relatively low effective orifice area.

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Section: Discussionmentioning

confidence: 99%

Comparative Analyses of Blood Flow Through Mechanical Trileaflet and Bileaflet Aortic Valves

Pawlikowski¹,

Nieroda²

2021

Preprint

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The paper describes one of many issues concerning the human circulatory system. The simulation of blood flow through an artificial aortic heart valve using the finite element method (FEM) is the main subject of the paper. The studies aim to verify the performance of mechanical aortic valves of two types, i.e. bileaflet (BIL) and trileaflet (TRI) valves. The blood was modelled as Newtonian and non-Newtonian. Although the design of our TRI valve is preliminary and needs to be optimised, our results highlight some advances of such a valve geometry. This is manifested mainly by a central blood jet, contributing to more physiological blood flow and decreasing the risk of haemolysis. The central flow minimises the risk of leaflet dislocation. In addition, lower stresses extend the durability of the valve. However, the TRI valve geometry has also disadvantages, for instance, the occurrence of small peripheral streams or relatively low effective orifice area. The valves' performance was assessed by means of the reduced stress in the valves, the shear stress in the aortic wall, flow velocity field, and the effective orifice area. The maximum von Mises stress for the BIL valve leaflets is 0.3 MPa, and for the TRI valve: 0.06 MPa. The maximum flow velocity for the BIL valve is 4.52 m/s for 40° and for the TRI valve is 5.74 m/s. Higher shear stress is present in the BIL (151.5 Pa) than for the TRI valve (49.64 Pa).

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A novel trileaflet mechanical heart valve: first in vitro results

Cited by 10 publications

References 12 publications

Aortic valve replacement in sheep with a novel trileaflet mechanical heart valve prosthesis without anticoagulation

Aortic valve replacement in sheep with a novel trileaflet mechanical heart valve prosthesis without anticoagulation

Comparative analyses of blood flow through mechanical trileaflet and bileaflet aortic valves

Comparative Analyses of Blood Flow Through Mechanical Trileaflet and Bileaflet Aortic Valves

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