Novel Straight Type Aortic Cannula with Spiral Flow Inducing Design

摘要

Aortic cannula is one of major factors leading to adverse events such as thrombosis and atherosclerosis development during open heart surgery, due to oxygenated blood outflow with high velocity jet from heart lung machine (HLM) when exiting the cannula tip into the ascending aorta. It was discovered, and validated by several researchers that blood flow out of the left ventricle into the aorta is spiral in nature. In this study, a novel design in which internal profile of the cannula was made to induce spiral flow were tested by way of numerical simulation, and compared against existing commercial cannula. Three designs were tested, which differed in number of groove employed. Among the cannula model designs, cannula design with 4 grooves yielded the lowest value of maximum wall shear stress at testing tube with 3.778 (Pa) and highest value of area weighted helicity density at 11.829 m/s, 40 mm from cannula tips. Overall, spiral cannula models showed high potential in inducing spiral flow, while the effect on blood hemolysis is acceptable.