Problems after kidney transplantation

Kidney transplant, my body still in the old kidneys work? There is no relationship between vascular cut off?
If you do not cut off the relationship and blood vessels, the old injury of renal glomerular filtration rate decreased, there is protein, right? So why not change the renal protein after it?

Questions added:

Why stop the blood by the original kidneys are not up there?

After renal transplantation, the original kidney filtration rate will gradually cease, will direct the new kidneys filter blood, so naturally proteinuria disappeared, but sometimes also have some original kidney protein, only very small amounts Less and less able to detect almost, like, like water pipes, two pipes, one blocked, and only a small amount of water through the other one is adopted by most of the water ah, of course, will gradually stop, do not you think After the original kidney in renal transplant will slowly recover? the original internal structure of the kidney has been destroyed, of course, will slowly decline until the total loss of function