Kidney function at 18%, bad edema, very bad heart, 63...how long can i last without dialysis?

Stating dialysis: It seems as if you may be quite near the initiation of dialysis. Most diabetics start dialysis when they have less than 15% of their kidney function, non-diabetics start when their's is less <10%. You need to see a nephrologist and cardiologist to see if your renal and heart function can be improved to get rid of some of your edema. Ask your doctors for more information on your particular case.