Flow disturbance at the distal end-to-side anastomosis. Effect of patency of the proximal outflow segment and angle of anastomosis
H. M. Crawshaw, W. C. Quist, E. Serallach, C. R. Valeri and F. W. LoGerfo
We investigated the flow disturbance that occurs at the distal end-to-side
anastomosis. Clear plastic model end-to-side anastomoses were constructed
with inlet angles of 15 degrees and 45 degrees. Flow patterns were
visualized with steady and pulsatile flow using a dye-injection technique.
Multiple lateral pressure measurements were made in the region of the
anastomosis. A laser Doppler anemometer was used to measure near-wall
velocity. Flow disturbance was minimal when the inlet angle was low and the
proximal outflow segment occluded. Patency of the proximal outflow segment
or a high inlet angle may result in areas of boundary-layer separation,
with corresponding adverse pressure gradients at the anastomosis. These
separation regions are characterized by low near-wall velocity, which may
contribute to anastomotic hyperplasia.
