Influence of angle on wall shear stress distribution for an end-to-side anastomosis

Abstract

Purpose: The purpose of this article was to study the effects of anastomotic angle on the wall shear stress distribution for end-to-side anastomosis models under pulsatile flow conditions.

Method: The photochromic tracer technique was used to visualize the flow field and to determine the instantaneous wall shear stress at multiple locations simultaneously. Models with angles of 20, 30, 45, and 60 degrees were examined.

Results: For all angles, low shear stress was present at the heel and on the bed opposite the heel of the anastomosis apparently as a result of the complete occlusion of the proximal end of the host vessel. Near the toe, increased flow separation occurred with increasing angle. On the bed across from the toe, increasing the angle led to increased shear stress. In addition, in this region the anastomotic angle significantly altered other properties of the shear stress field such as the mean and peak-to-peak magnitudes and cycle-to-cycle fluctuations.

Conclusions: This study provides quantitative data on the wall shear stress distribution within an end-to-side anastomosis and its relation to the anastomotic angle. The results are discussed in terms of possible roles of shear-induced intimal hyperplasia.