Another good, homeopathic vet-approved raw food diet to consider. I noticed they also have a specially-formulated raw diet for cats with CRF (wish I'd known sooner, myself), as well as offering a product for teeth-cleaning that apparently works so well one need NOT have to take an animal in for regular cleanings, thereby reducing exposing them to the real and inherent risks of anesthesia.
Feline Instincts Raw Food Diets