NEW FEATURES OF THE INCOR AXIAL FLOW BLOOD PUMP DIRECT MEASUREMENT OF ABSOLUTE PRESSURE AND FLOW RATE. TECHNICAL AND CLINICAL ASPECTS

Abstract

The INCOR axial LVAD, with a magnetically-suspended rotor, has been in clinical use for two years. Measurement of the pressure difference across the pump and the flow rate is an inherent feature of the magnetic bearing. Nevertheless, there has been a continued demand for a system that can provide continuous dynamic left-ventricular pressure information. This allows enhanced control features such as controlled unloading of the left ventricle in order to promote the recovery of cardiac function. Redundant measurement of the flow rate is another desirable feature. We have integrated additional pressure and flow sensors into the pump without increasing the volume of the implanted components. Miniaturized piezo-resistive pressure sensors for direct measurement of absolute pressure are located in the inflow and outflow hubs. A miniaturized ultrasound-based (US) flow-rate sensor mounted on the outside of the titanium tube is an integral part of the pump and measures the flow without coming into direct contact with the blood. The function of the pump does not depend on the integrity of the sensors. The pressure sensors are able to measure the absolute pressure with high time-resolution (<3 ms). The tested long-term stability is +/− 1.5 mmHg per year. The US flow rate sensor is extremely reliable and provides redundant information on the pump functions. Sensors providing measurements with long-term accuracy have been integrated in the pump without increasing its volume. The functionality and safety of the system have been improved.