Key result
Trileaflet mechanical aortic valves reduce maximum von Mises stress by ~80% vs bileaflet valves.
Why the study?
The comparative performance of bileaflet and trileaflet mechanical aortic valves under uniform blood flow conditions and the impact of Newtonian versus non-Newtonian blood flow assumptions were not well characterized.
Does a trileaflet mechanical aortic valve improve hemodynamic performance compared to a bileaflet valve in a computational model?
Does a trileaflet mechanical aortic valve improve hemodynamic performance compared to a bileaflet valve in a computational model?
Absolute Event Rate: 0.06% vs 0.3%
Computational modeling indicates that trileaflet mechanical aortic valves may offer more physiological central blood flow and lower mechanical stresses than bileaflet valves, potentially reducing hemolysis risk.
Hypothesis-generating for trileaflet designs; leaves open whether benefits translate to clinical outcomes.
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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Pawlikowski et al. (2021) studied Aortic valve disease. Trileaflet mechanical aortic valve vs. Bileaflet mechanical aortic valve was evaluated on Maximum von Mises stress. The trileaflet mechanical aortic valve demonstrated lower maximum von Mises stress (0.06 MPa vs 0.3 MPa) and lower shear stress (49.64 Pa vs 151.5 Pa) compared to the bileaflet valve.
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