Department Seminar of Ilan ben Uliel - Numerical biomechanics modeling of a passive device for treatment of heart failure with preserved ejection fraction
School of Mechanical Engineering Seminar
Wednesday 20.11.2023 at 14:00
ZOOM SEMINAR
Numerical biomechanics modeling of a passive device for treatment of heart failure with preserved ejection fraction
Ilan Benoliel
M.Sc. student of Dr Gil Marom
School of Mechanical Engineering, Tel Aviv University, Tel Aviv, Israel
Heart failure, defined as a global pandemic, describes a diseased state of the heart where its pumping ability has been reduced to the extent that it cannot meet the body's demands. The prevalence of heart failure with preserved ejection fraction (HFpEF) appears to be increasing over time with the aging of the population. HFpEF is characterized by the inability of the heart to properly relax and expand during diastole to be filled with enough blood from the left atrium. To date, the diagnosis of HFpEF remains challenging and no treatment has been shown to convincingly reduce mortality and morbidity in patients. Therefore, an effort to develop and evaluate device-based therapies is an important emerging area. This study aims to simulate and optimize the function of passive assist devices for the treatment of HFpEF in a beating pathologic heart. Thus, the current study proposes to focus on and analyze a left ventricle (LV) expander device type that is designed to improve the heart’s relaxation performance. The device, implanted inside the LV, acts like a spring that stores the elastic potential energy from its systolic deformation and helps expand the ventricle during diastole by pushing the relaxed muscle. Therefore, the device should have a direct mechanical effect on the diastolic function and the filling performance. The aims of the present study include two steps. First, to model the hypertrophy of a HFpEF heart by modifying a model of a healthy heart. Second, to optimize the shape, size, and material of the passive assist device. To achieve this aim, device implantation will be modeled inside the diseased heart model from the first aim. The heart model in this study is based on the Living Heart Human Model (Simulia, Dassault Systèmes). The devices considered in this study have a similar design to the Corolla device, but several geometries and materials have been considered and compared. The effect of the various devices on the heart’s function was quantified based on the calculated pressure-volume loops, focusing on the increased ventricular volume during relaxation while not compromising the ejection fraction. Finally, fatigue analyses were performed on the optimal design to assess the long-term impact and durability of the device. The results revealed that cobalt-chromium material seems to be more appropriate than nickel-titanium for this type of application. It was also found that the LV expander consistently demonstrated LV pressure reduction and an increase in the LV volume, while larger devices were able to improve cardiac performance more than the smaller ones. Furthermore, it was demonstrated that the modeled device is incapable of enduring 4∙108 cycles, equivalent to 10 years, but capable to endure 108 cycles. Nonetheless, it is worth considering that severe HFpEF patients typically have a life expectancy of less than 10 years, and therefore further analysis is needed to check the device in the context of clinical needs.
https://tau-ac-il.zoom.us/j/86497933118
