Related Experiment Videos
Axial flow fields in cuffed end-to-side anastomoses: effect of angle and disease progression
L D Wijesinghe1, T Mahmood, D J Scott
1Department of Vascular and Endovascular Surgery, St James's University Hospital, Leeds, U.K.
Objective:
to visualise the axial flow fields in standard and cuffed end-to-side anastomoses (ESA).
Design:
in vitro experiments using a flow rig, custom-built glass models and frame-by-frame video analysis of flow patterns in standard and cuffed ESA.
Subjects:
glass models of standard or cuffed (1 cm or 2 cm high) ESA of angles 15, 30, 45 and 60 degrees.
Results:
the cross-sectional area of standard ESA is much smaller than that of ESA between graft and cuff. The size of the vortex in the anastomotic zone of both standard and cuffed ESA increased with increasing ESA angle and cuff height, but did not change with flow rate. The presence of the vortex maintains a zone of flow separation and low shear at the heel of standard and graft/cuff anastomoses.
Conclusions:
the observations explain the clinical findings of intimal hyperplasia (IH) at the heel of PTFE/cuff anastomoses. The improved patency rates of cuffed ESA may be due not to decreased IH, but to an increased ability of the cuff to accommodate IH before causing a significant stenosis.