An On-demand Morphing Impeller Pump for Low-Speed, Hemocompatible pVADs

Percutaneous ventricular assist devices (pVADs) are vital for acute cardiogenic shock, yet their performance is limited by the small delivery profile required for femoral access. This constraint restricts impeller size and necessitates ultra-high rotational speeds for adequate blood flow, which in turn increases hemolysis risk. Here we present the on-demand Morphing Flexible Impeller Pump (MFP), which mitigates this trade-off via an integrated deployable linkage system inspired by umbrella opening mechanisms. This system converts simple pushing force into complex spatial deformation of the pump's flexible blades, allowing the MFP to transition from a 7 mm-diameter catheter-deliverable profile to a 16 mm-diameter helical pumping configuration in situ. The enlarged pumping geometry achieves a clinically relevant pressure gradient of 10 mmHg at 4000 rpm, markedly lower than reported speeds of typical micro-axial pumps. CFD analyses showed that shear stresses were largely below the hemolysis-related threshold (150 Pa), with minimal high-stress volumes. Consistently, in vitro experiments showed hemolysis indices comparable to clinically used pumps (e.g., Impella CP) under matched hemodynamic conditions. By decoupling delivery size from pumping capacity, this morphing-impeller strategy offers a promising route toward safer and more efficient minimally invasive circulatory support.