Abstract
The rat femoral vein has become a standard model for laboratory training in microvascular anastomotic technique as well as for research investigations into factors affecting venous patency. This study examined the short‐term patency (1 and 7 days) of rat vein anastomoses. The influences upon patency of epigastric flap creation and distal femoral vessel ligation (epigastric flow only) were explored. In a separate experiment, blood flow from the femoral vein was determined through catheter collection of venous efflux; the influences of island epigastric flap creation and distal femoral ligation on flow rates were explored. It was found that 82% of basic femoral vein anastomoses were patent at one day, while 100% of anastomoses associated with an epigastric flap and ligated/transected distal femoral vessel circulation (creating a low‐tension anastomosis) were patent (P<0.01). With distal femoral vessel ligation and no transection (normal tension at the repair), anastomoses were patent in 90% of the veins when an epigastric flap was also raised, and in 60% when a flap was not created. When a flap was raised without disturbing the distal femoral circulation, vein patency was 75% at one day. When the vein anastomosis was performed with distal femoral vein ligation, the patency rate was 50%. All veins patent at 1 day were also patent at 7 days post‐op; 96% of veins clotted at 1 day were found to be patent at 7 days. The venous efflux was not found to vary significantly when an epigastric flap was raised. These results indicate an increase in patency through reduction of longitudinal tension and suggest that island/free flaps have a beneficial influence upon the prevention of venous occlusion. The high rate of recanalization in thrombosed veins indicates a potential source of error in previous studies in which vein patency was evaluated only at longer postoperative times. © 1992 Wiley‐Liss, Inc.