Concepção de bancada e montagem de experimento para a análise in vitro de próteses cardíacas mitrais

Bazan, Ovandir; Ortiz, Jayme Pinto

doi:10.1590/s0102-76382011000200009

Cited by 3 publications

References 22 publications

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Active Pneumatic Pulsation Damper for Peristaltic Pump Flow Loops

Liermann

2016

BATH/ASME 2016 Symposium on Fluid Power and Motion Control

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A novel concept of an active pulsation damper is described that cancels parasitic flow pulsatility of peristaltic pumps and is able to inject desired pulsatility signatures such as physiological heart beat. Peristaltic pumps avoid contact between the moving parts of a pump and the operating fluid. They are used for clean or sterile fluids as well as for highly aggressive fluids, whenever it is important to isolate the fluid from the environment. The background application for the proposed active pulsation damper is the simulation of hemodynamic flow. The paper presents a novel pulse damper concept that allows the use of roller or peristaltic pumps as primary pumps for hemodynamic flow loops. The problem with peristaltic pumps is that they exhibit a high parasitic pulsatility that needs to be canceled before a desired pulsatility can be injected. The active pulsation damper does this and is also used to superpose a desired flow pattern that resembles measured heart flow rate profiles. The nonlinear dynamic equations of a test system with active pulsation dampers are established and linearized to allow a first analysis of the achievable bandwidth. Simulation results of the closed loop system are presented based on the non-linear equations.

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Active Pneumatic Pulsation Damper for Peristaltic Pump Flow Loops

Liermann

2016

BATH/ASME 2016 Symposium on Fluid Power and Motion Control

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Laser Doppler anemometry measurements of steady flow through two bi-leaflet prosthetic heart valves

Bazan¹,

Ortiz²,

Junior³

et al. 2013

Revista Brasileira De Cirurgia Cardiovascular

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IntroductionIn vitro hydrodynamic characterization of prosthetic heart valves provides important information regarding their operation, especially if performed by noninvasive techniques of anemometry. Once velocity profiles for each valve are provided, it is possible to compare them in terms of hydrodynamic performance. In this first experimental study using laser doppler anemometry with mechanical valves, the simulations were performed at a steady flow workbench.Objective To compare unidimensional velocity profiles at the central plane of two bi-leaflet aortic prosthesis from St. Jude (AGN 21 - 751 and 21 AJ - 501 models) exposed to a steady flow regime, on four distinct sections, three downstream and one upstream. MethodsTo provide similar conditions for the flow through each prosthesis by a steady flow workbench (water, flow rate of 17L/min. ) and, for the same sections and sweeps, to obtain the velocity profiles of each heart valve by unidimensional measurements. ResultsIt was found that higher velocities correspond to the prosthesis with smaller inner diameter and instabilities of flow are larger as the section of interest is closer to the valve. Regions of recirculation, stagnation of flow, low pressure, and flow peak velocities were also found. Conclusions Considering the hydrodynamic aspect and for every section measured, it could be concluded that the prosthesis model AGN 21 - 751 (RegentTM) is superior to the 21 AJ - 501 model (Master Series). Based on the results, future studies can choose to focus on specific regions of the these valves.

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Experimental validation of a cardiac simulator for in vitro evaluation of prosthetic heart valves

Bazan¹,

Ortiz²

2016

Brazilian Journal of Cardiovascular Surgery

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ObjectiveThis work describes the experimental validation of a cardiac simulator for three heart rates (60, 80 and 100 beats per minute), under physiological conditions, as a suitable environment for prosthetic heart valves testing in the mitral or aortic position.MethodsIn the experiment, an aortic bileaflet mechanical valve and a mitral bioprosthesis were employed in the left ventricular model. A test fluid of 47.6% by volume of glycerin solution in water at 36.5ºC was used as blood analogue fluid. A supervisory control and data acquisition system implemented previously in LabVIEW was applied to induce the ventricular operation and to acquire the ventricular signals. The parameters of the left ventricular model operation were based on in vivo and in vitro data. The waves of ventricular and systemic pressures, aortic flow, stroke volume, among others, were acquired while manual adjustments in the arterial impedance model were also established.ResultsThe acquired waves showed good results concerning some in vivo data and requirements from the ISO 5840 standard.ConclusionThe experimental validation was performed, allowing, in future studies, characterizing the hydrodynamic performance of prosthetic heart valves.

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Concepção de bancada e montagem de experimento para a análise in vitro de próteses cardíacas mitrais

Cited by 3 publications

References 22 publications

Active Pneumatic Pulsation Damper for Peristaltic Pump Flow Loops

Active Pneumatic Pulsation Damper for Peristaltic Pump Flow Loops

Laser Doppler anemometry measurements of steady flow through two bi-leaflet prosthetic heart valves

Experimental validation of a cardiac simulator for in vitro evaluation of prosthetic heart valves

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