If it's Chronc Renal Failure, many of us have benefitted from the information at http://www.felinecrf.com/index.htm

Please check with your vet, but my understanding is that the kidneys can compensate up to about 70 or 75% loss. It's at that point that you first see the rise in creatinine -- and so that is considered early renal failure.


The heart condition of course does affect the condition of the kidneys.