Experimental Validation of a Cardiac Simulator for in vitro Evaluation of Prosthetic Heart Valves.

Ovandir Bazan,Jayme Pinto Ortiz

doi:10.5935/1678-9741.20160041

Abstract

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.

Highlights

Pulse duplicator systems or cardiac simulators have been designed to replicate the pressure and flow waves according to the human cardiovascular physiology[1,2,3,4,5,6,7,8]
left ventricular pressure (LVP) versus left ventricular volume (LVV) diagram (PxV diagram) were plotted as shown in Figure 6, with each loop averaged over five consecutive cycles
The cardiac simulator was validated to these conditions, in accordance with the human physiological parameters

Summary

Introduction

Pulse duplicator systems or cardiac simulators (i.e., left ventricular models) have been designed to replicate the pressure and flow waves according to the human cardiovascular physiology[1,2,3,4,5,6,7,8]. Once the evaluation of left ventricular assist devices is performed, for instance, based on adaptive estimation of the aortic pressure and suitable response regarding the left ventricular contractility variation[10,17,18,19,20], the operation of cardiac simulators in this case is designed to an automatic variation of cardiovascular parameters (according to the Frank-Starling mechanism), requiring a full closed-loop control. In terms of prosthetic heart valves testing, the cardiac simulators are used only to conduct cyclic operation with good repeatability, in some predicted ventricular conditions[12]. In this case, the cardiac simulator control system can be simplified, but the ventricular model is expected to mimic some anatomical

Methods

Results

Discussion

Conclusion