A novel design of ventricular assist device: an in vitro feasibility study

Left ventricular assist devices (LVADs) work as a bypass between the left ventricular apex and the ascending aorta. The surgical procedure for their insertion requires the opening of the cardiac cavities and the dissection of the great vessels, the blood is constrained to flow through the device components and the risk can be run of thrombogenesis, haemolysis and infections. A possible strategy to overcome this limitation consists in utilizing external systems that assist the heart in its contraction from the outside without directly transporting the blood. In this study we conduct the feasibility analysis of a novel external LVAD design that does not require the opening of the cardiac cavities and the dissection of the great vessels and that allows the removal procedure to be easily achieved. The device, including a stepper motor, three metallic wires and three elastic elements, works alternatively between a contraction condition where it induces an elastic compulsion on the heart and a release condition where it elastically releases the organ. The values of force acting on the wires and the values of current supplied to the motor were measured and utilized for a preliminary study design. The experimental measurements demonstrated the feasibility of the system.