Innovative Implantable Left Ventricular Assist Device—Performance under Various Resistances and Operating Frequency Conditions

Abstract

This paper presents the operation of an innovative left ventricular assist device under various resistances and operating frequencies. The operating principle of the device is based on pulsatile blood flow, which is forced by a suction–discharge device pumping helium into a set of intra-cardiac balloons. In this way, the ejection fraction of the left ventricle is increased, and the mitral valve is additionally occluded. What is more, the suction–discharge device is part of a portable pumping system that is synchronized with the heart cycle by monitoring the ECG signal. The device is implanted in a minimally invasive manner and is suitable for patients with stage D heart failure accompanied with residual mitral regurgitation. A model of the heart was built on the basis of a realistically reconstructed heart geometry and is part of an overall test stand that allows for realistic conditions in the heart of patients with end-stage heart failure to be reproduced. In the following sections, example measurements of the pressures in the heart chambers and balloons are shown, demonstrating that the device works correctly at least on a laboratory scale. The entire device, including the pumping system, is portable and powered by a set of lithium-ion batteries. From the measurements, it was observed, for example, that the flow rate varies with the frequency of the portable external balloon pumping system, up to 2.5 kg/min for 100 cycles/min at low flow resistance. As the flow resistance of the hydraulic system increases, the pressure in the heart chamber and aorta increases while the flow rate decreases.

Effect of Vascular Lumen Reduction on the Performance and Energy Consumption of an Innovative Implantable LVAD

“…This paper extends the research presented in [35] by investigating the effect of reduced lumen on the performance of an innovative left ventricular support device. The reduction of the vascular lumen was achieved by changing the cross-sectional area of the adjustable hydraulic valve, which is located a short distance from the aorta.…”

“…The results obtained in terms of pressure measurements mean that the innovative implantable LVAD proposed here can operate over a wide frequency range, i.e., from 60 to 160 cyc/min, extending the applicability of the device at much higher operating frequencies than in [35].…”

“…A CAD model of the left ventricle with limited myocardial contractility is presented in Figure 1. A description of the procedure for reconstructing the heart geometry from selected computed tomography angiography is presented in [35]. In brief, the model considered the left ventricle, atrium, and aorta for a left ventricular ejection fraction of 30% in both systole and diastole, which corresponds to a case with chronically low ejection fraction.…”