Renal transplantation in cats
Policy type: Guideline
Date ratified: March 2017
Chronic kidney disease (CKD) is very common in older cats. There are various causes of the disease including infections, toxins, tumours and polycystic kidney disease (particularly in Persians).
Cats can tolerate transplantation from unrelated animals of the same species, but must continue to be supported with immunosuppressive drugs, to reduce rejection risks for the rest of their lives.
Cats who donate kidneys must be assessed for suitability (they are usually young, healthy cats), they are then anaesthetised and have a single kidney removed ( a nephrectomy). The transplant is implanted in the recipient cat through vascular surgery under anaesthesia, with the original kidneys usually left in place.
Kidney transplant is a controversial treatment option and views on its acceptability differ among clinicians and countries (Yeates, 2014).
The first kidney transplantation in a cat was performed in 1984 at the University of California, Davis (UCD). There are currently ten centres in the world that offer kidney transplants for cats. Nine of these are in the US and one is in Australia. The UC Davis centre that pioneered this surgery in 1984 have since abandoned their programme.
The United Kingdom (UK) permitted this procedure in 2003, but in 2013 it was suspended pending a review. The UK Royal Society for the Prevention of Cruelty to Animals (RSPCA) have threatened to prosecute veterinarians carrying out the procedure under the 1911 Protection of Animals Act, on the grounds that it causes unnecessary suffering to donor animals (Chapman, 2013).
Currently, kidney transplantation is relatively rarely performed in cats worldwide.
The New Zealand Veterinary Association does not support feline kidney transplant programmes in New Zealand for the following reasons:
Lack of evidence that it provides clear benefits
Kidney transplantation is not a cure for CKD.
While kidney transplantation can result in long survival times in some patients, complications following kidney transplant surgery are common (Schmiedt, Holzman, Schwarz, & McAnulty, 2008).
Complications include transplant rejection, infections, diabetes (Bernsteen, Gregory, Kyles, Wooldridge, & Valverde, 2000), retroperitoneal fibrosis in a substantial percentage of patients (Wormser, Phillips, & Aronson, Retroperitoneal fibrosis in feline renal transplant recipients: 29 cases (1998–2011)), and hypertension (Kyles, et al., 1999). Malignant neoplasia is also encountered in greater-than-normal numbers following kidney transplantation, thought to be related to the immunosuppression therapy (Wooldridge, Gregory, Mathews, Aronson, & Kyles, 2002).
In consideration of the above, and in line with the International Cat Care (ICC) position on kidney transplant (International Cat Care, 2015), it is not clear that cats undergoing kidney transplantation would necessarily survive any longer than cats managed with good medical supportive care (Elliot & Barber, 1998).
Ethical concerns around donors
A number of ethical considerations are raised with transplant programmes on where and how a donor kidney is sourced.
There are differing views on whether it is preferable to recover and rehome the donor cat or source the kidney from a non-recovery procedure in an animal that was otherwise going to be euthanased.
Several shelters in the United States offer schemes to owners of cats with CKD in which they can adopt a shelter cat to donate a kidney to their cat. The cat trading a kidney for a home may be viewed as beneficial to the donor. The ethical consideration of this situation must include the consideration that the nephrectomy has the potential to reduce the donor cat’s well-being and life expectancy. A recent study on the outcome for donor cats found 7% of feline kidney donors developed renal insufficiency or died of urinary tract disease (Wormser & Aronson, 2016).
It cannot always also be assumed that the donor cat will enjoy his new life – it could experience inter-cat aggression in the new home, or the new owners may even be neglectful.
Another view is that removal of a kidney during non-recovery surgery from a cat that would otherwise be euthanased is a more acceptable source of a kidney for transplantation. The ethical considerations in this case include wider indirect adverse effects such as misuse, unfairness and demotivation to rehome a cat (Yeates, 2014).
Concerns around the ability to provide the level of care required of a transplant patient
For kidney transplantation to be successful there must be a dedicated team of veterinary professionals, this includes medicine, surgery, and emergency & critical care specialists. It is not a procedure that can be performed adequately by individuals working in isolation from this level of support.
A kidney transplant recipient cat requires lifelong immune-suppressive medication to manage transplant rejection. Medicating cats orally is challenging for many owners and failure to consistently do so is a significant cause of transplant failure (Gregory, 2010).
Cats on long-term immunosuppressive medication are at risk of acutely developing debilitating complications such as fatal toxoplasmosis (Bernstein, Gregory, Aronson, Lirtzman, & Brummer, 1999). To maintain the recipient cat’s well-being, the owners must be able to urgently access specialist care for the rest of the cat’s life. While all veterinary centres offer 24-hour emergency care, access to a team of specialist who can provide the level of support needed is not routinely accessible at all times. Without this level of support, there are unacceptable risks to the kidney recipient’s long-term welfare.
Bernsteen, L., Gregory, C., Kyles, A., Wooldridge, J., & Valverde, C. (2000). Renal transplantation in cats. Topics in Companion Animal Medicine, 15(1), 40-45. doi:http://dx.doi.org/10.1053/svms.2000.7303
Bernstein, L., Gregory, C., Aronson, L., Lirtzman, R., & Brummer, D. (1999). Acute toxoplasmosis following renal transplantation in three cats and a dog. Journal of the American Veterinary Medical Association, 215(8), 1123-1126.
Chapman, J. (2013). Just how much do you love your cat? Retrieved 2016, from Daily Mail Australia: http://www.dailymail.co.uk/news/article-169382/Just-love-cat.html
Elliot, J., & Barber, P. (1998). Feline chronic renal failure: clinical findings in 80 cases diagnosed between 1992 and 1995. Journal of Small Animal Practice, 39, 78-85.
Gregory, C. (2010). Clinical renal transplantation in the cat. Feline Medical Symposium. Texas: College of Veterinary Medicine & Biomedical Sciences. Retrieved from URL: http://www.vin.com/doc/?id=4367197
International Cat Care. (2015). Chronic kidney disease in cats – management. Retrieved from International Cat Care: http://icatcare.org/advice/cat-health/chronic-kidney-disease-cats-%E2%80%93-management
Kyles, A., Gregory, C., Wooldridge, J., Mathews, K., Aronson, L., Bernsteen, L., & Ilkiw, E. (1999). Management of hypertension controls postoperative neurologic disorders after renal transplantation in cats. Veterinary Surgery, 28, 436-441. doi:10.1111/j.1532-950X.1999.00436.x
Schmiedt, C., Holzman, G., Schwarz, T., & McAnulty, J. (2008). Survival, complications, and analysis of risk factors after renal transplantation in cats. Veterinary Surgery, 37(7), 683-695. doi:10.1111/j.1532-950X.2008.00435.x.
Wooldridge, J., Gregory, C., Mathews, K., Aronson, L., & Kyles, A. (2002). The Prevalence of Malignant Neoplasia in Feline Renal-Transplant Recipients. Veterinary Surgery, 31(1), 94-97. doi:10.1053/jvet.2002.30540
Wormser, C., & Aronson, L. (2016). Perioperative morbidity and long-term outcome of unilateral nephrectomy in feline kidney donors: 141 cases (1998–2013). Journal of the American Veterinary Medical Association, 248(3), 275-281. doi:10.2460/javma.248.3.275
Wormser, C., Phillips, H., & Aronson, L. (n.d.). Retroperitoneal fibrosis in feline renal transplant recipients: 29 cases (1998–2011). Journal of the American Veterinary Medical Association, 243(11), 1580-1585. doi:10.2460/javma.243.11.1580
Yeates, J. (2014). Ethical considerations in feline renal transplantation. The Veterinary Journal, 202, 405-407.