Elliptic st. jude bileaflet mechanical heart valves

Abstract

St. Jude Medical (SJM) bileaflet mechanical valves were approved by the Food and Drug Administration in 1977. The SJM valve design consists of two semicircular leaflets which pivot on hinges. Compared to other mechanical heart valve prostheses such as ball and cage and tilting disk prosthetic valves, it provides good central flow, the leaflets open completely, and the pressure drop across the valve is trivial. However, non-physiological hemodynamics around these valves may lead to red blood cells lysis and therombigenic complications. Also, the regurgitation-flow inSJM valves is almost twice that of the native valves in the aortic position. In this study, we suggest a new design for the stent (housing) of SJM valves in which 15% ovality is applied to the stent whereas its perimeter remains constant. In a pilot study, the hemodynamic performance of the proposed design is analyzed in the closing phaseand compared to that of conventional SJM models. Results show that while the elliptic SJM model offers a shorter closing phase (9.7% shorter), the regurgitation flow remains almost unchanged. In other words, even though the dynamic response of the valve is improved, the regurgitation flow is not decreased. Thus, a more efficient effective orifice area (EOA) is shown to be provided by the proposed model. The preliminary calculations presented in this study justify an improved hemodynamics of elliptic SJM valves compared to conventional models; the proposed design shows promise and merits further development.

Effect of heart rate on the hemodynamics of bileaflet mechanical heart valves’ prostheses (St. Jude Medical) in the aortic position and in the opening phase: A computational study

“…The findings of this study are of particular importance for the design improvement of the conventional MHVs and the design of the next generation of prosthetic heart valves. 42,43…”

“…The findings of this study are of particular importance for the design improvement of the conventional MHVs and the design of the next generation of prosthetic heart valves. 42,43 We consider the hemodynamic analysis of SJM valve at and near the peak flow, when the leaflets are fully open and it is safe to assume fixed leaflets at the maximum opening angles. According to the numerical and experimental studies, for example, Yoganathan et al, 8 Choi and Kim 17 and Mohammadi et al, 2 the opening and closing phases of the MHVs take about 20-30 ms, while the fully open phase is around 200-300 ms.…”

Hemodynamic study of the elliptic St. Jude Medical valve: A computational study

“…The proposed ESJM model has an elliptical stent with a major diameter of 27 mm and a minor diameter of 23 mm (Figure 1(c)), corresponding to ∼10% ovality of the housing. 7 Since the valve diameter was reduced from 25 mm in the SJM model to 23 mm to the ESJM model (minor axis), the leaflet length and valve profile were consequently reduced from 12.8 and 11 mm in the SJM model 15 to 11.2 and 9.5 mm in the proposed model, respectively, as shown in Figure 1(d) and (e).…”

“…Using a customized computational model developed at the Heart Valve Performance Laboratory (HVPL) at the University of British Columbia (UBC), the overall hemodynamic performance of the proposed elliptic St. Jude Medical (ESJM) valve was studied. 7 We also developed a computational platform where the hemodynamic performance of the bileaflet MHVs in the opening phase can be evaluated. 8 In this study, we assessed the hemodynamics of the proposed design in more detail using the computational fluid dynamics (CFD) and compare it with the SJM valve in the opening phase.…”

Prosthetic Aortic Heart Valves

“…It should be noted that they have similar mechanical properties to fibroblasts or smooth muscle cells. As well, they are significantly effective in the regular function of the aortic valve and undertakedimensionalchanges during the closing and opening phases [64][65][66][67][68][69].…”