Preparation of the vessel ends
Cut the vessel midway between the approximator clamps.
Irrigate immediately after cutting, to prevent blood clot formation. Remove excess liquid. Rinse again until the fluid inside the vessel stumps and your whole operating field is clear. If you cannot irrigate the whole length of vessel, try to remove the blood by gently brushing over the vessel with the smooth outer edge of an instrument.
Keep the operating field wet and the adventitia well soaked in order to see its tissue better and to maintain its flexibility for easier trimming. Pull the adventitia over the cut edge of the vessel and cut it back in a circular manner, holding your scissors parallel to the cut edge. Tearing the adventitia with a forceps would leave fuzzy streaks of tissue that could be introduced into the lumen when penetrating the vessel wall with the needle. Thrombus formation could result.
Check whether you have removed the adventitia from the cut edge all the way around the vessel. For greater ease of handling, brush the remaining adventitia away from the cut edge.
The vessel is dilated to one and a half times its original diameter to paralyze its smooth muscle and to make the anastomosis easier to perform.
Now move the approximator clamps closer together and align the vessel, leaving a small gap to be able to see needle and suture inside the