Intracorporeal Biventricular Assist Devices Using the Heartware Ventricular Assist Device in Children

Advancement of the Dragon Heart 7-Series for Pediatric Patients With Heart Failure

BACKGROUND

Safe and effective pediatric blood pumps continue to lag far behind those developed for adults. To address this growing unmet clinical need, we are developing a hybrid, continuous-flow, magnetically levitated, pediatric total artificial heart (TAH). Our hybrid TAH design, the Dragon Heart (DH), integrates both an axial flow and centrifugal flow blood pump within a single, compact housing. The axial pump is embedded in the central hub region of the centrifugal pump, and both pumps rotate around a common central axis, while maintaining separate fluid domains.

METHODS

In this work, we concentrated our design and development effort on the centrifugal blood pump by performing computational modeling. An iterative process was employed to improve the DH design. The pressure generation, scalar stress levels, and fluid forces exerted on the magnetically levitated impellers were computationally estimated. A shaft driven centrifugal prototype was also manufactured and tested using a hydraulic flow loop circulating a water-glycerol blood analog. Pressure and flow performance of the pump prototype was measured for a given rotational speed for comparison to computational predictions.

RESULTS

Our design achieved the target pump pressures of 60-140 mm Hg for flow rates of 1-5 L/min, and strong agreement in pressure rise was demonstrated between the experimental data and simulation results (less than 10% deviation on average). Fluid stress levels were, however, found to exceed thresholds in the outflow region of the pump, and fluid residence times were less than 600 ms.

CONCLUSION

The findings of this work demonstrate that the more compact, next-gen DH's centrifugal pump design is able to achieve pressure-capacity requirements. Next steps will require a focused strategy to reduce hemolytic potential and to integrate magnetic suspension components for full rotor levitation.

Heart Transplant Outcomes After Total Artificial Heart

BACKGROUND

We sought to compare heart transplant (HTX) outcomes from patients with a total artificial heart (TAH), biventricular assist device (BiVAD), or left ventricular assist device (LVAD) as a bridge to transplant (BTT). Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS)-Scientific Registry of Transplant Recipients (SRTR) created a dataset with TAH or durable mechanical circulatory support (MCS) who reached HTX between 2006 and 2015.

METHODS

The retrospective analysis compared TAH outcomes with those with a BiVAD or LVAD before HTX. The primary outcome was posttransplant survival at 1, 36, and 60 months. Secondary outcomes included simultaneous heart-kidney transplants, donor characteristics, and mortality risk factors. INTERMACS-SRTR cohort had, at the time of HTX, 2762 patients with LVAD; 205 BiVAD (139 durable and 66 temporary RVAD); 176 TAH (6 prior HeartMate II).

RESULTS

Sixty months after HTX, mortality rates were 16.5% in the total group: LVAD 15.2%, BiVAD 22.4%, and TAH 29%. Survival differed between the LVAD, the TAH, and BiVAD but not between the BiVAD and TAH groups. One-year survival and complication rates were similar across groups-there was no difference in survival by donor age in the overall cohort. There was a difference in TTD based on recipient age in the LVAD group but not in BiVAD or TAH groups. Occurrence of HTX-kidney and post-transplant dialysis were higher in the TAH versus LVAD and BiVAD groups.

CONCLUSIONS

The TAH is an efficacious BTT. Refinements in technology and patient selection may improve outcomes.

Safety issues with an inter-hospital transport of a patient with a Berlin Heart Excor biventircular assist device

BACKGROUND

Interhospital transfers of pediatric patients on the Berlin Heart Excor have been published on an occasional basis.

METHODS

Nowadays medicine evolves away from just feasibility towards quality and safety issues. Management tools like risk analysis have found their way into clinical practice.

RESULTS

Exemplary, we present a case of a 20 months old boy on a Berlin Heart BiVAD Excor who underwent a 224 km ground transport. After a systematic review of the published literature, we describe our safety management with the aim was to provide highest quality of care for the transport.

CONCLUSION

Besides a risk analysis, we also describe our training and simulation protocol.