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Veterinary Forum November 2008 (Vol 25, No 11)

Your role in caring for kidney transplant patients

by Marie Rosenthal

    The referring veterinarian is involved in before and aftercare for most transplant patients because only a few hospitals perform the procedure.

    The before and aftercare for most transplant patients falls to the referring veterinarian because feline kidney transplantations are performed in only a few hospitals in the United States. Veterinary Forum talked with several transplant surgeons to find out what you need to know to discuss this procedure with clients and what type of before and aftercare you can expect to provide for these feline patients.

    With a price tag of $8,000 to $13,000, kidney transplantation is not an option for every client, but there are quite a few who consider it a viable chance to save a dying pet. Cats that receive a transplant can live 3 or more years, and many live longer than 6.

    Transplantation did not become viable until the development of the immunosuppressant cyclosporine because the animal's immune system would reject the graft without the drug. The University of California, Davis, School of Veterinary Medicine opened the first kidney transplant program in the mid-1980s, and today only a few centers across the country have programs.

    The price tag is probably the biggest obstacle for most clients. They need to understand that the costs are high because they are paying for surgery and medical care for two cats — the transplant recipient and the donor . Owners are paying for hospital stays of up to 2 weeks, two surgical procedures, ICU care for the recipient, blood products, pre- and postsurgical workup, anesthesia, plus medication and monitoring. In addition, owners will need to give the recipient cat medication for the rest of its life, which is likely to cost around $1,000 a year.

    Several pet insurance companies told Forum that they do cover some aspect of the kidney transplantation, depending on the type of policy covering the cat. Primary care veterinarians need to advise owners to check their individual policies to see if any part of the procedure will be covered and to contact their insurer before the surgery if they have any questions.

    After the transplant procedure, cats are close to normal and many owners are pleased to see their "old" cat again, say transplant experts — so the money becomes a secondary issue. "The quality of life is better for the animals," says Jonathan McAnulty, DVM, MS, PhD, professor of surgery, University of Wisconsin"Madison School of Veterinary Medicine. "They tend to gain weight and become more active."

    "I have interacted with many clients over the years," says Lillian R. Aronson, VMD, DACVS, associate professor of surgery in the department of clinical studies at the University of Pennsylvania School of Veterinary Medicine. "Whether we agree or not, the physical and emotional effects of sickness and the loss of a pet are real [issues for owners]. I can see how some people would think that anything done in veterinary medicine is excessive, but many people are very attached to their animals. These pets are family."

    Medical management with diet and fluid therapy is still the mainstay for all cats with chronic renal failure, but even with the best management, eventually the kidneys will fail. Timing for the transplant is everything; surgeons do not want to perform the surgery too soon or too late.

    "The question is when, but I don't think anyone knows [the answer] for sure," says Chad Schmiedt, DVM, DACVS, instructor at the University of Georgia College of Veterinary Medicine. "There is some magic point at which the benefits outweigh the risks. We know you should not do a transplant as soon as you diagnose early kidney disease because a lot of cats can live a couple of years with a low level of kidney disease. It doesn't make sense to do a transplant with a 613-day mean survival rate when they may live relatively asymptomatically for 2 years without a transplant," Schmiedt says, citing data from Wisconsin.

    "The best bet is to treat them medically first, and before they start to decompensate and get really sick, do the transplant. But that will be different for each cat," he said.

    Aronson agrees: "I don't think anyone knows the best time. I was taught [to do the surgery] when the animal is in early decompensated kidney failure. So, in the face of medical management, it has started to deteriorate and may be losing some weight or becoming anemic."

    Good transplant candidates are cats without other significant problems, such as FIV or FeLV, neoplasia, overt heart disease or uncontrolled diabetes. Age is less of a factor, but owners tend to have surgery on cats younger than 10. Penn is still compiling its data, but they see many cats older than 10 years of age.

    "We are looking for a patient whose main problem is kidney failure and doesn't have any other significant disease processes, such as neoplasia, heart disease or unregulated diabetes. They may have other problems, but kidney disease is the main [one]," says Aronson.

    Veterinarians traditionally were asked to make sure that the cat was very stable before transplantation, but that is not the case today. "If you have an acute crisis, certainly you can put them on fluids and get their BUN and creatinine down. But when you reach a certain level of renal failure, pumping them full of fluids is not going to make a big change," McAnulty explains. "More important than trying to get a cat with acute renal failure ready for a transplant is to get them in early enough that they don't present in crisis.

    "We like to see a creatinine value greater than 4 [mg/dl] because it reflects a significant loss of kidney function and gives us enough space to evaluate the function of the graft relatively easily as the creatinine falls after surgery," says McAnulty. "However, some cats with creatinine values less than 4 mg/dl will develop significant electrolyte abnormalities, anemia and other secondary effects of chronic renal failure, in which case I think they are better off going ahead with the transplant."

    The surgery is complex and challenging and takes about 4 hours. Most of the risk for the cat is during and immediately after surgery. Complications include bleeding, hypertension, embolism, infection and rejection of the new organ. The mortality for transplants from complications at the time of surgery, including animals with end-stage renal failure, is 10% to 20%.

    "But if they get through surgery and go home, more than 90% of cats will survive beyond a year, and most will survive 3 years or more," McAnulty says.

    How long recipient cats remain in the hospital after surgery depends on each cat's progress, as well as the location of the hospital and the owner. Because only a handful of centers perform these surgeries, many owners travel across state lines to have the procedure done in their cats. They tend to stay in the hospital longer to ensure that they are doing well before they are released to the referring veterinarian. The surgeon wants to be assured that the kidney is functioning and the blood levels for cyclosporine are correct before discharging the patient. The patient may go home on fluids, antibiotics, even a feeding tube, as well as cyclosporine and steroids.

    The owner must adopt the donor cat, but it does not normally require special medical care after surgery, the experts say. The donor cat does not typically need any follow-up care except for its routine healthy cat care.

    Once the transplant recipient is released, it is important for the referring veterinarian to keep an eye on the cyclosporine levels and monitor the cats for complications. Make sure that the graft is still functioning and the glucose level is not too high, as these patients are at risk for developing diabetes because of cyclosporine and steroid treatment. The referring veterinarian also needs to deal with any infections appropriately and quickly. The referring veterinarian and the transplant surgeon normally continue to work closely in the management of these cats, the experts tell Forum.

    "We rely on the referring veterinarian for a lot of the aftercare, but we are in constant contact with them as well as owners for the rest of the cat's life," Aronson says.

    Typically, the referring veterinarian needs to see the cat once a week for the first 4 to 6 weeks, then every 4 to 6 weeks and eventually every quarter, depending on how the cat is doing.

    "The aftercare is really twofold: It is observational, making sure the cat is doing okay, and also, if there is anything questionable on presentation, doing blood work and making sure the cat is being medicated every day," McAnulty says.

    Surgeons expect recipient cats to have BUN and creatinine levels within normal ranges. Most surgeons do not recommend a renal diet after surgery, but others recommend that the cat stays on the renal diet.

    To get the best possible match for the organ, surgeons do a blood crossmatch to ensure that the donor and the recipient are compatible. It increases the odds that the organ will be accepted but doesn't prevent all rejection.

    "Acute rejection is fulminate; the cat feels really sick. The transplanted organ swells, and the animal can die from the rejection reaction," explains Schmiedt. "Another form of rejection is called chronic rejection or chronic allograft nephropathy. In one study, 76% of cats had evidence of chronic rejection. The condition is not usually fatal. The graft deteriorates over time, but that takes years. I think the cats end up dying from something else before they die from chronic rejection."

    Signs of chronic rejection are similar to signs of early renal failure. "The initial signs can be fairly vague — a little malaise and loss of energy and appetite. That is what owners notice most," says McAnulty.

    Some experts say it is probably best if cats become indoor-only pets because their immune systems are depressed, but others say that it is okay for them to act like normal cats.

    Vaccination is another issue. You might be a little reluctant to give a transplant recipient a vaccination, but again, opinions and recommendations differ. "I would consider vaccinating them with a killed vaccine," says Aronson. "We went to a lecture on this at the human hospital because we were curious. It is an issue with children. Pediatricians end up having to vaccinate the children more because they are on immunosuppressive drugs and they are suppressing the immune response's ability to fight off infection.

    "We haven't had a case like this yet," she adds. "I am still cautious."

    "I'd be reluctant to vaccinate them," says Schmiedt. "If you do, you might want to check titers first and see if the cat needs it."

    All of the surgeons see a time when renal transplants become more common.

    "The thing that would change the frequency of [renal] transplants in veterinary medicine would be to establish an effective means of preventing graft rejection in dogs," says McAnulty.

    Aronson recently performed the second canine kidney transplant, but in both cases, the donor was a relative: mother to puppy and sibling to sibling. "The surgery is not any harder," she says, "but the problem is with rejection afterward. Dogs seem to have a greater problem when they receive a kidney from an unrelated dog."

    When surgeons at UC Davis tried to perform renal transplants on unmatched dogs, the recipients suffered severe complications from receiving so many immunosuppressants. "We are working on that right now and trying to figure out how to transplant unrelated dogs successfully," Aronson says.

    Schmiedt indicates that expense vs. life expectancy will always be an issue. "I think part of the problem is the expense," he says. "If there was something we could do to knock that down≥and if we could get the survival times out longer, I think people would be more likely to do it.

    "I hope more owners do it because it is amazing to see the cats go from these chronic withering sickly cats to running around the house and playing. They get the sparkle back in their eyes."

    NEXT: ACVIM Foundation funds cancer and MRSA studies

    didyouknow

    Did you know... If a patient has not eaten for 4 days or longer, nutritional support should be considered if it is not contraindicated because of vomiting, regurgitation, or megaesophagus or because nothing can be given by mouth before sedation for diagnostic procedures or surgery.Read More

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