Hydrodynamic Impact of Flexible Blades in Left Ventricular Assist Devices

Left Ventricular Assist Devices (LVADs) are widely used to support patients with end-stage heart failure. To match the LVAD output with the patient's cardiac output, the operating speed is often adjusted, which can impact device efficiency and longevity. To address this, we have developed a novel LVAD prototype with flexible rotor blades. Our hypothesis is that the mechanoresponsive behavior of the flexible blades will allow them to adapt to complex inflow conditions, thereby improving the hydrodynamic performance of the device and offering a broader range of operational speeds with optimal efficiencies.

In this study, we evaluate the hydrodynamic performance of flexible rotor blades in a centrifugal LVAD under adult physiological conditions (5 L/min, 90 mmHg). The prototypes were tested on a benchtop setup using a blood-mimicking solution. The pressure-flow curve gradient and efficiency were used to assess the device's performance. High-speed 2D particle image velocimetry was employed to capture flow fields within the LVAD, using fluorescent particles to identify regions of stagnation and high shear stress. Preliminary results show that the flexible rotor blades generate a flatter pressure-flow curve, improving the LVAD’s preload sensitivity and allowing for a wider operational range with greater efficiency. This study highlights the potential of flexible rotor blades to improve the hydrodynamic performance of LVADs, contributing to more efficient and durable devices.