Q: My 60 years old mother was put on dialysis using a mature AV fistula on her left arm for a few months. Now she has to have a mastectomy for breast cancer, which is also on her left side. The doctors say that they have to close down the working fistula and create a new one on the other arm because the surgery will cause it to fail and could bleed out/kill her. Is there no way to keep/maintain the fistula? I think that they could save it if they shunt/divert the flow, so the pressure doesn't build up (break and bleed out) or quit flowing (clotting and causing failure) into a catheter in another part of the body. Can it be done? Our doctor has never heard of vein mapping and is not ready to do that. Please advise.

A:You have to understand that for everyone, including doctors, a usual situation is easy to handle. I have never had to carry out a mastectomy in an arm with an AV fistula. Nor do the books describe such a situation. Therefore I have to use my knowledge of the basics of body physiology and surgery, and suggest an answer. An AV fistula increases the blood supply to the veins of the arm. The blood goes back to the heart through the axillary vein, which is in the armpit. Surgeons also touch the axillary vein during breast cancer surgery; therefore in theory there could be a problem from an exuberant axillary vein. Bleeding may be more than usual. But will the bleeding be so much that the surgery cannot be performed? I think not. With a bit of care it should be easy to handle the bleeding. (The bleeding from this site should not be life-threatening: the axilla is just not a site where bleeding becomes uncontrollable.) If the bleeding is actually so profuse that the surgery is difficult, the blood supply can always be blocked off temporarily by placing a tourniquet on the arm. I know that it is not as simple as I am making it sound, and there are other factors to be considered like thrombosis in the fistula, but in my opinion it is possible to operate on the arm without fear of bleeding. However, surgeons are worried not only about bleeding. There is also the concern about lymphatics: these are thin tubes, thinner than veins, and drain water from the arm. After surgery a third or half of the lymphatics get destroyed in the armpit. In some patients this becomes a big problem, therefore cancer surgeons just don't like anything to be done on the same side arm. Some surgeons are so fussy (even neurotic) that they do not allow an intravenous drip to be inserted into the same side arm. So I can understand what is making your surgeon so uncomfortable. Sitting far away, it is easy for me to say that there are no problems: the operating surgeon carries all the responsibility. The chances of lymphatic complications are fewer than 10 percent, but that ten percent is scary, since the patient suffers terribly. My final verdict is this. If I were the surgeon, I would not dismantle the fistula; and I would do a careful, even slightly-less-than-usual dissection in the armpit. Cancer surgeons may strongly disagree with this statement, but this is what I feel. (Remember, however, that I have not seen the patient nor examined the lump.) Vein mapping? I don't think this is the right setting for it. Forget it, that's my advice. Shunting or diverting the fistula? I don't agree: too many, too many issues there. I hope this helps.