Comparative computational fluid dynamic study of two distal Contegra conduit anastomoses.

A computational fluid dynamic (CFD) study compared two configurations of distal anastomosis of 12 mm Contegra conduit: conventional 'circular' vs. oblique 'elliptical' anastomosis extended on the left PA, evaluating pressure and velocity profiles, and shear stress, from PA origin to the bifurcation. 'Elliptical' anastomosis provides larger (=54% difference) cross-sectional area than 'circular' anastomosis. Velocity contours showed important stagnation at PA bifurcation in 'circular' anastomosis and minimal in 'elliptical' configuration, where fluid flow occurred preferentially in left PA. Pressure contours showed peak pressure zone at bifurcation in 'circular' anastomosis, while 'elliptical' exhibited more uniform pressure distribution. Shear stress distribution was more homogeneous in 'elliptical' than in 'circular' anastomosis. At bifurcation and in right PA artery velocity and pressure were higher for 'circular' than 'elliptical' anastomosis, while in left PA velocity was much higher for 'elliptical' anastomosis. CFD study demonstrates more homogeneous pressure, velocity and shear stress distributions for 'elliptical' compared to 'circular' anastomosis at PA bifurcation, and preferential flow in left PA. CFD results suggest that clinical application of 'elliptical' anastomosis, with cross-sectional area larger than conventional 'circular' anastomosis, may reduce incidence and degree of distal stenosis, particularly for small size conduits.