Doc takes no Medicare

I have a very important question and wonder if anyone older who has had this surgery has run into this problem. My doctor does not take Medicare/AARP. It is not in his circle of insurance coverages. WHAT DO I DO IF I NEED CARE WITH MY RNY? I have other doctors, but none who are versed in gastric bypass issues. Who or where do I find one who will take over for my surgeon. I feel abandoned by this issue. I'm 65 and had the RNY 4 years ago. I feel good, take all my vitamins, have regular bloodwork done, including liver tests my original surgeon required. So, who do I contact if something goes wrong, or better still a doctor who will keep an eye on me FOREVER with this surgery. Thanks. Marilyn