SIMULATION STUDY ON INFLUENCE OF LEAFLET SHAPE AND OPEN ANGLE OF TRI-LEAFLET MECHANICAL HEART VALVE ON BLOOD FLOW
Keywords:
Tri-leaflet mechanical heart valves, leaflet shape, leaflet open angleAbstract
A mechanical heart valves is a device implanted in patients with the dysfunctional heart valves. It has been using to save many lives. Several types of mechanical heart valves have been developed to improve hemodynamic of blood that flows through the valves. The open angle and the curvature of leaflet of the mechanical heart valves may affect the hemodynamic of blood flow. Therefore, this paper was aimed to study on the influence of fully open angle and the curvature of the leaflet shape of the valves on velocity and shear stress of blood flow through tri-leaflet mechanical heart valves. This paper studied on three dimensional models of eight tri-leaflet mechanical heart valves: flat tri-leaflet heart valves at the fully open angles of 85, 87, and 90 degree, curved tri-leaflet heart valves with the curved inner radius of 8.672 mm at fully open angle of 85, 87, and 90 degree, curved tri-leaflet heart valves with the curved inner radius of 8 and 9.328 mm at fully open angles of 85 degree. The SST k-ω turbulent model in FLUENT was applied to analyse unsteady incompressible blood flow. As the results of computational simulation, the maximum shear stress was found at after peak systole phase in both flat and curved tri-leaflet heart valves. The flat tri-leaflet heart valve at the fully open angle of 90 degree provided the highest shear stress of blood flow compared with the flat tri-leaflet heart valves at other levels of open angle. While the curved tri-leaflet heart valve at the fully open angle of 85 degree provided the highest shear stress of blood flow compare with the curved tri-leaflet heart valves at the other levels of open angle. The highest velocity was found in the region between leaflets for all types of tri-leaflet heart valves, resulting in high shear stress in that region. Therefore, the fully open angle and the leaflet shape of tri-leaflet heart valves affect to velocity profile and shear stress of blood flow that may lead to blood clotting conditions in the mechanical heart valves.
References
Bang, J.S., Yoo, S.M., and Kim, C.N., (2006). Characteristics of pulsatile blood flow through the curved bileaflet mechanical heart valve installed in two different types of blood vessels: velocity and pressure of blood flow. ASAIO J., 52(3):234-242.
Bluestein, D., Rambod, E., and Gharib, M., (1999). Vortex shedding as a mechanism for free emboli formation in mechanical heart valves. J. Biomec. Eng., 122(2):125-134.
Cheng, R., Lai, Y.G., and Chandran, K.B. (2004). Three-dimensional fluid-structure interaction simulation of bileaflet mechanical heart valve flow dynamics. Ann. Biomed. Eng., 32:1,469–1,480.
Gallegos, R.P., Rivard, A.L., Suwan, P.T., Black, S., Bertog, S., Steinseifer, U., Armien, A., Lahti, M., and Bianco, R.W. (2006). In-vivo experience with the Triflow trileaflet mechanical heart valve. J. Heart. Valve. Dis., 15(6):791-799.
Ge, L., Dasi, LP., Sotiropoulos, F., and Yoganathan, AP., (2008). Characterization of hemodynamic forces induced by mechanical heart valves: Reynolds vs. viscous stresses. Ann. Biomed. Eng., 36(2):276-297.
Grigioni, M., Daniele, C., D'Avenio, G., and Barbaro, V. (2001). The influence of the leaflets’ curvature on the flow field in two bileaflet prosthetic heart valves. J. Biomech., 34(5):613-62.
Hong, T. and Kim, C.N., (2011). A numerical analysis of the blood flow around the Bileaflet Mechanical Heart Valves with different rotational implantation angles, Journal of Hydrodynamics, Ser. B, 23(5):607-614.
Kiang-ia, A. and Chatpun, S., (2013). Mechanical analysis of mechanical aortic heart valve: Trileaflet versus bileaflet. Proceeding of Biomedical Engineering International Conference; October 23-25, Krabi, Thailand.
Krishnan, S., Udaykumar, H.S., Marshall, J.S., and Chandran, K.B. (2006). Two-dimensional dynamic simulation of platelet activation during mechanical heart valve closure. Ann. Biomed. Eng., 34:1,519–1,534.
Lee, H., Tatsumi, E., Homma, A., Tsukiya, T., and Taenaka, Y. (2006). Mechanism for cavitation of monoleaflet and bileaflet valves in an artificial heart. J. Artif. Organs., 9:154.
Li, C.P., Chen, S.F., Lo, C.W., and Lu. P.C. (2011). Turbulence characteristics downstream of a new trileaflet mechanical heart valva. American Society for Artificial Internal Organs 57(3):188-96.
Pibarot, P. and Dumesnil, J.G. (2009). Prosthetic heart valves: selection of the optimal prosthesis and long-term management. Circulation, 119:1,034-1,048.
Shahriari, S., Maleki, H., Hassan, I., and Kadem, L., (2012). Evaluation of shear stress accumulation on blood components in normal and dysfunctional bileaflet mechanical heart valves using smoothed particle hydrodynamics. J. Biomech., 45(15):2,637-2,644.
Yoganathan, A.P., He, Z., and Jones, S.C. (2004). Fluid mechanics of heart valves. Ann. Rev. Biomed. Eng., 6(1):331-362.
Yun, B.M., Aidun, C.K., and Yoganathan, A.P., (2014). blood damage through a bileaflet mechanical heart valve: a quantitative computational study using a multiscale suspension flow solver. J Biomech Eng 136(10):17.
