Improved hydrodynamics of a new aortic cannula with a novel tip design.

BACKGROUND Reduction of atheroembolic complications during cardiopulmonary bypass remains a major challenge in cardiac surgery. New cannula tip designs may help to attenuate this problem by improved hydrodynamics. METHODS Pressure gradients and back pressures of a new aortic cannula tip design were measured and compared with the Medos X-Flow, Sarns Soft-Flow and Argyle THI cannulae at various flow rates in a mock circulation followed by flow visualization. RESULTS Pressure gradients were the lowest for the new cannula. Back pressures of the new cannula were up to 84% lower than for the Argyle cannula. The back pressure profile and flow visualization of the new cannula showed broad centric flow dispersion with a transcannula increase of flow area from 38 mm2 to 139 mm2. CONCLUSIONS The new design of an aortic cannula tip provides improved hydrodynamics, with low pressure gradients, low back pressures and a uniform central dispersion of flow, reducing the sandblasting effect.