Filament support spindle for an intravascular cavopulmonary assist device.

We are developing an intravascular axial flow blood pump to support adolescent and adult Fontan patients. To protect the blood vessel, this pump has an outer cage with radially arranged filaments and a newly designed spindle at the pump outlet. The outlet spindle is included to limit the axial movement of the rotor and to house bearings that support the rotor. This study evaluates the impact of the outlet spindle on pump performance using computational fluid dynamics (CFD) and experimental testing of a prototype configuration. We measured the pressure-flow performance of the prototype with a protective cage using a blood analog fluid. The pump with the cage filaments and spindle generated 1 to 16mmHg of pressure rise for flow rates of 1 to 4L/min at 4000 to 7000rpm. The difference between the CFD predictions and experimental results was found to be approximately 9.8%. Scalar stress levels remained below 570Pa with exposure times on the order of 1.5s. These results are acceptable and support the continued development of this cavopulmonary assist device with an outlet spindle to reinforce the protective cage filament design.