Rotor for a transventricular blood pump.

• Ano de defesa: 2019
• Autor(a) principal: Andrade, Gustavo Caravita de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Axial flow pump; Bomba de fluxo axial; Computational fluid dynamics; Dinâmica dos fluidos; Dispositivo de assistência ventricular; Estudo fluidodinâmico; Impeller; Método dos elementos finitos; Simulação computacional; Transventricular; Ventricular assist device; Ventrículo cardíaco
• Link de acesso: http://www.teses.usp.br/teses/disponiveis/3/3152/tde-21102019-085421/

According to the World Health Organization, cardiovascular diseases (CVDs) are the number one cause of death worldwide, except in Africa, where Acquired Immunodeficiency Syndrome is the leading cause of death. In this context, the continued development of new devices to assist blood pumping until the transplant, has great value. The Dante Pazzanese Institute of Cardiology (IDPC, São Paulo, Brazil) has recently started a research and development project aiming an axial flow blood pump to be fully implanted within the heart. This pump, called Transventricular Assist Device (TVAD), can be implanted surgically through a small left intercostal incision in a minimally invasive manner. The objective of this research is to develop and analyze the rotor of the TVAD, aiming at the best conditions to support the circulatory system and to achieve: minimum areas of recirculating/stagnating flow and minimum shear stresses. The study is conducted through Computational Fluid Dynamics (CFD) and In Vitro tests. Based on literature, a sort of rotors featuring different geometries and number of blades are defined and tested. The hydrodynamic characteristics of the rotors are compared each other so as to determine the best one. Besides, studies are performed to determine the importance of volute vanes in the TVAD pumping characteristics. Finally, studies are carried out to verify the influence of the gap reduction between the periphery of the blade and the volute on the pumping characteristics as well on the hemolysis. The study showed that the rotor that presented the best performance were the rotor with two blades of constant pitch arranged each other at 180º. Suggesting that, for this device: (I) the higher the blade pitch, the higher the pressure load, the lower flow rate, and increases shear stress; (II) a variable pitch decrease the pump efficiency and (III) a non-continuous blade decreases significantly the pump\'s hydrodynamic performance and decreases the shear stress. At this speed, the maximum manometric head was of 126 mmHg and a maximum flow rate of 4.5 L/min. It is expected to have a low normalized index of hemolysis (NIH).