Ultracompact magnetically levitated BiVAD for low-body-weight pediatrics

Dear Editor,

End-stage heart failure has become a major global health challenge.1 The global scarcity of pediatric donor organs results in an insufficient number of annual heart transplantations to meet the clinical demands of children with end-stage heart failure.2 While ventricular assist devices (VADs) serve as an effective alternative to heart transplantation, only 448 pediatric VAD implantations were reported in the United States from 2012 to 2021, according to the Pediatric Interagency Registry for Mechanical Circulatory Support (PediMACS).3 Similarly, pediatric VAD utilization in Europe has remained limited over the past two decades. Currently, only first- and second-generation pumps are internationally available for children, with no third-generation, fully magnetically levitated VADs specifically designed for pediatric use. The most commonly used HeartMate III is restricted to older children.4 Notably, China currently lacks dedicated VADs specifically designed for infants and young children.

Furthermore, for children with biventricular failure, the application of biventricular assist devices (BiVADs) in pediatric populations ≤30 kg presents unique physiological challenges, including limited thoracic capacity and low-flow requirements.5 Here, we independently developed the third-generation magnetic levitation pump, the D-miniCor, a 45 g (single-pump) magnetically levitated VAD with pediatric-optimized size and dual 5 mm cables. We put it to clinical use for a 7-year-old child with end-stage biventricular failure and make a brief report. This technology has opened a gap in pediatric heart failure management where a necessary alternative to transplantation did not previously exist, even achieving a more than 3 month survival in initial patients to using the device.

The design and structure of D-miniCor

While axial magnetic levitation has been adopted in some third-generation LVADs, the D-miniCor features a proprietary implementation: a single-coil, integrated electromagnetic design that simultaneously handles both impeller rotation and axial suspension control, which is distinct from the multi-coil or hybrid suspension system in other devices (Figures 1A and 1B). Through real-time dynamic magnetic field modulation, the system maintains micron-level precision in stabilizing the impeller (Figure 1C). Its hemocompatibility is enhanced by a low-shear impeller design and optimized flow dynamics: the helical primary flow path eliminates stagnant zones, while linear secondary channels reduce recirculation. Adaptive clearance control, enabled by active magnetic suspension and real-time feedback, dynamically maintains optimal clearance between the impeller and housing. This design minimizes flow stagnation zones and promotes physiological wall shear stress distribution, thereby reducing thrombus risk (Figures 1C and 1D).