- Turn bovie down to 20 - Score thoracic fascia on the medial aspect of mammary - Start at the tips of the three rib interspaces below the Angle of Louis - Find vein in rib interspaces - The artery will be visualized beyond the vein. Once an idea of the quality of the conduit is formed, communicate with assistant harvesting vein so that final determination of the quantity of venous conduit needed is decided. If mammary is poor, start mentally considering using it for a diagonal, or supplementing its LAD use with an LAD vein. - Use unlit bovie to push vein then artery away from rib - Clip vein/artery branches on the mammary side - The vein/artery branches have a specific anatomic pattern depending on the region of the mammary. To begin with, they obviously do not occur at the ribs. They may originate a little over the superior and inferior margin of the rib, and then coast along it, but they will tend to be clustered just below or above the rib at the intercostal spaces. From the Angle of Louis to the junction of the xyphoid and the sternum, the branches tend to occur in pairs, one set towards you, one set away from you. A small clip may be perfectly suitable, but often, it is possible to clip a vein and artery branch at one blow with a medium clip. There is nothing wrong with this. At the Angle of Louis, there is a very large vein/artery branch that will often require a medium clip to securely traverse it. Once this branch is down, one is typically able to get back in through the pleura on the far side of the mammary, and the harvesting will proceed more quickly. Above the Angle of Louis, the branches tend to be smaller and all go away from you, and venous branches are rarer. Approaching the area of the junction between sternum and xyphoid, the ribs tend to fuse with the sternum in a much less individual way, without much interspace to deal with. Branches are large, and tend to go away from you, until you reach a tri- or bi-furcation where the IMA has a watershed with the inferior epigastric.[^a] - Bovie vein/artery branches on the chest wall side. - Penetrate thoracic fascia and parietal pleura on lateral aspect of mammary by going over the mammary - As the pedicle drops away from the chest wall, it improves exposure to the remainder of the vessel - Consider changing deployment of RULtract mammary retractor when reaching area of the large venous branch at the Angle of Louis - Elevate chair/rotate table towards you - Continue harvest from Angle of Louis until subclavian vein is visualized - Rotate table away from self - Continue harvest from fifth/sixth rib interspace until past junction of sternum and typhoid - Ask anesthesia to give heparin - It is a common variation to give the heparin well after the mammary has been cut, and this usually works out fine, and is certainly compatible with harvesting both mammaries, then giving the heparin. Others go to the extreme of leaving the IMA's hanging from the chest wall until the time that the heparin is given, just before going on pump. Infrequently, but with regularity, one will see a thin strand of clot that has formed inside the mammary when one is preparing the tip for anastomosis. This thin strand will be pulled out, and have a distressing length, and one will wonder how often this is happening, and we never know about it. For this reason, it seems a happy compromise to give the heparin before clipping the mammary. Moreover, if the heparin is given at this point, enough time will have typically passed before aortic cannulation that an ACT is available before putting a plastic tube in the largest artery as it travels in the direction of the brain.[^b] - When heparin is given, clip each terminal branch with three medium clips - Cut terminal branches of mammary with tonotomy scissors - Inspect caliber of mammary, strength of bleeding, then clip the bifurcated terminal branches with medium clips - What to do if the mammary is small - The mammary may be small because of conduit spasm, and may look better after it has had some time to soak in papaverine. But what if it isn't going to get better? You will need another length of vein for grafting, or if arterial conduit is desperately required, you may have to consider the RIMA or a radial. Is there a diagonal it can be sewn to? Is the mammary better more proximally? Can the portion that is better be stretched to reach the target by partially or completely skeletonizing it? If it is used to the mammary, it may grow with time, but you may not want to leave it as the only conduit going to the LAD. As the saying goes, "a good vein is better than a bad mammary". - Is flow through the mammary inadequate?[^c] - Lay out mammary on a ray-tech sponge opened lengthwise - Spray mammary and sponge with papaverine - Inspect carefully for any missed branches to be clipped - Fold ray-tech sponge over mammary, tuck into chest - Announce that one ray tech is going into the left chest, in a voice that can be heard by the circulator. - Turn bovie up to 80 - Bovie all bleeding points on interior chest wall - Remove laparatomy sponge packing from left pleura - Count them out, as you counted them in, in a voice that the circulator can hear. - Remove RULtract retractor [^a]:See [[Anatomic Considerations of Internal Mammary Artery Harvest]] [^b]:See [[Philosophies in the Timing of Heparin Administration]] [^c]:See [[What to Do If Mammary Flow is Inadequate]]