IN-VIVO MEASUREMENTS OF BLOOD-FLOW VELOCITY PROFILES IN CANINE ILIOFEMORAL ANASTOMOTIC BYPASS GRAFTS

In-vitro velocity profiles were recorded with a 20 MHz, 80-channel pul sed Doppler ultrasound velocimeter in canine end-to-side ilio-femoral anastomotic grafts. The geometries were obtained from casts of the ana stomotic region, and flow rates were measured with electromagnetic flo w probes. Three cases reported here include a ''standard'' geometry wh ich was similar to previously studied in vitro models, a stenosed geom etry, and a case with below average flow rate. Observed flow features include separation at the hood and toe, movement of the floor stagnati on point, and skewed profiles in the proximal outflow segment. Out-of- plane curvature and lateral displacement of the anastomosis inlet appe ar to have a strong effect on the flow fields. In addition, compliance affects the instantaneous flow rates within the proximal and distal b ranches.