P24: Mechanical Circulatory Support Device Technologies Incorporating Mechanical Pressure Regulation

Abstract

Study: Mechanical circulatory support (MCS) devices perform in variable hemodynamic environments and must enable changes in speed, flow, and pressure based on performance requirements dictated by specific clinical states. In order to perform as intended, sensing of hemodynamic environment, and having a mechanism of pressure regulation, are necessary when experiencing differential pressures during operation inside a circulatory system. Herein, we report MCS devices with this pressure regulation feature. Methods and Results: By creating a passive rotor assembly through magnetic scheme and physical geometry of the housing’s interior, minimal pressure differentials upstream and downstream are able to influence the rotor’s position. In Figures 1 A and B, our universal ventricular assist device (UVAD) is depicted in open and closed positions, respectively. The rotor (shown in tan) spins about the (black) motor coils, but is also able to move axially (up and down in these figures), depending on the pressures acting on it. In Figure 1 C, flow shut off occurs when the rotor shoulder (located at the base of impeller blades) is near the corresponding internal shoulder of the (blue) housing, reducing the aperture between these features. Thus, limiting blood flow through the UVAD. Similarly, this passive rotor movement is designed into our family of continuous-flow total artificial hearts (CFTAH). Pressure differences generated by the left and right sides of the heart influence and affect the rotor’s axial position, regulating pressure and flow. Our pediatric CFTAH (P-CFTAH) is shown in Figure 1 D. Conclusion: Due to the environment, in which these devices operate, we can take advantage of the inherent differential pressures experienced, and simplify operation and control of our MCS devices. We have successfully implemented passive rotors in several developmental iterations of the UVAD, and three versions of our CFTAH (adult, pediatric, infant).