Optimisation of the Sputnik-VAD design

Purpose: Miniaturisation of VADs can offer important benefits, including less invasive implantation techniques and more versatility in patient selection. The aim of this work was to reduce the weight, size, and energy consumption of the Sputnik VAD. Methods: The second generation of the Sputnik VAD was developed with a set of changes in construction. The head pressure-flow rate (H-Q) and power consumption-flow rate curves for the Sputnik VADs were measured at different rotational speeds. Computational fluid dynamics (CFD) were used for operating condition simulation and the LVADs were compared under the simulated physiological conditions. Results: The slope of the H-Q curves for the Sputnik 1 VAD remains almost invariable over the entire range of the measured flow rate, in contrast to the curves for the Sputnik 2 VAD, which become flat in the high flow-rate region. Despite the design modification, the operating rotor speed remained invariable. The preload sensitivity of the Sputnik VAD is higher than that of the other rotary blood pumps and amounts to 0.111 +/- 0.0092 L min(-1) mm Hg-1. The power consumption for the Sputnik 2 VAD is lower over the entire speed range, except for at 5,000 rpm. Conclusions: The pump weight was reduced from 246 to 205 g, the pump length was decreased from 82 to 66 mm, and the pump diameter was decreased from 32 to 29 mm. The total energy consumption of the pump was reduced by 15%.