Dialysis

Cats are the most common patients needing hemodialysis therapy. Most patients have acute renal failure, where dialysis is a temporary procedure until normal kidney function returns. In very rare circumstances (due to the unwillingnes of pet owners to pay for such a costly therapy), cats with chronic renal failure follow hemodialysis therapy for the remainder of their lives. Also, cats that have consumed antifreeze (ethylene glycol) can be saved if they are placed on hemodialysis within 6 hours of the ingestion.

Because there is considerable risk and cost associated with hemodialysis, it is reserved until standard therapy (intravenous fluids, medications, etc.) have proven ineffective. Patients with immediately life-threatening complications of kidney failure, like high potassium levels or fluid in the lungs, may benefit from immediate dialysis.

According to the prices set by a facility in San Diego, the intial setup for dialysis (including catheter, first week of treatments, feeding tube, etc.) is around $2,500 to $3,000. Each treatment, of which there are 3 per week, cost $500 each. Currently, only a handful of centers perform hemodialysis. For a list of participating veterinary hospitals, click here.

Peritoneal dialysis can also be performed on a feline with renal failure. PD is a lot easier than hemodialysis to perform in cats and is not painful. Of course, the need for monitoring and professional assistance limits PD applications to cats with reversible acute renal failure while the kindeys are recovering.

Kidney Transplantation

Chronic renal failure (CRF) is a gradual loss of function of the kidneys over time which continues until the residual kidney function is insufficient to support life. A kidney transplant is one possible therapy that has the ability to drastically improve the quality of life of a feline. Although CRF is considered a geriatric disease, kittens as young as 9 months have been reported to have the disease caused by congenital or inherited renal diseases.

In a compensated state of renal failure, the cat can tolerate the ever-increasing amounts of waste in the blood and does not show any symptoms of illness. Typically, these cats are maintained on subcutaneous liquids or maintained diets. Eventually, the cat will enter a decompensated state where weight loss increases and uremia (uncontrolled toxic condition) develops. Since it can not be predicted when a cat will enter the decompensated state, these animals should have a transplant as soon as possible. Additionally, a weight loss of 20% or more can reduce the chance for success during a transplant surgery, so transplants should be performed at the beginning of the symptom emergence. Another warning of the decompensated state is the inability to maintain metabolic processes, like the development of anemia or an inability to balance calcium or phosphorus concentrations in the blood.

Most of the kidneys implanted in cats will fail about 3 years, so it may be beneficial to time the transplantation procedure to obtain maximum benefits for the kidney recipient. The kidneys that fail within 3 years typically develop graft vascular disease, which causes the blockage of the renal arteries and subsequently a slow loss of kidney function.

The School of Veterinary Medicine at the University of California , Davis began in the mid-1980s to offer a kidney transplantation program for chronic renal failure in cats. Contemporarily, this organization performs more kidney transplants than any other center in the country. Because of this establishment, the transplantation surgery has become wholly a routine rather than an experimental procedure. Currently, transplanted kidneys can add about 2-6 years to the patent's life, with a 80-90 percent success rate for good candidates. This high statistic can be attributed to better donor selection, a more rigid candidate qualification, and improved surgical techniques.

The actual transplantation requires up to four hours in the operating room. Just as with humans, the recipient's kidneys are usually not removed and the new kidney is attached directly to the bladder. The veins, arteries, and ureter attachments that are required for completion of the transplant are performed with an operating microscope. While the patient is anesthesized, a stomach tube is inserted to prevent starvation if the cat won't eat in recovery.

During recovery, a course of antibiotics is given; but the patient will have to remain on cyclosporine and prednisolone for the remainder of their life. Cyclosporine is oily, and must be placed into a gel cap by a pharmacist or by the cat owners to be consumed every twelve hours.

The cost of a kidney transplant, plus the follow-up care, is around $6,000 to $11,000, depending on the specificity of the surgical procedure and the availability of viable kidneys.

Pacemakers

The feline heart functions in the same way the human heart works, except that it beats much faster (at about 200 beats/minute compared to 60-100 beats/minute in the human). Most abnormalities in cats take the form of bradyarrhthmia, or slow heart rate. Rate-modifying drugs may not provide enough assistance to those with sick sinus syndrome or severe atrioventricular block. This is where pacemakers come in.

Veterinary pacemakers can come from several sources, including:

•  Human models that have small, unimportant defects that prevent their use in people

•  Models that are recycled from human cadavers

•  Brand-new models that are past their shelf life

In 2000, a pediatric pacemaker was implanted into a cat that was suffering from frequent prolonged episodes of complete atrioventricular block with ventricular standstill. The surgery and initial recovery went well, but there were complications a few months after surgery. The cat, named Tooye, developed chylothorax or an accumulation of lymphatic fluid in the chest that is caused by irritation from pacemaker leads. The liquid was drained periodically, but it returned even with medications used to treat chlothorax in humans. The owners decided to put their pet to sleep, just five and a half months after the pacemaker was implanted.

Currently, there are only a few cases per year of pacemaker surgery in cats. Most complications from the surgery are associated with progressive myocardial disease or congestive heart failure. The average cost of both implantation and monitoring of a cat pacemaker is around $1,000, although price may vary based on regional access or type of veterinary practice.

Valve Replacement/Coronary Artery Bypass Surgery

There are only infrequent cases of valve repair in cats. Currently, there is no standard of care for the replacement of valves in felines. Rare case studies exist, such as the 4-month old kitten who underwent open heart bypass surgery to have a valve defect corrected. Besides experimental situations, there are no reported instances of biprosthetic or synthetic valves being placed in a cat.

Hip Replacement

Hip dysplasia is a chronic, progressive disease that cannot be completely cured with the use of medications. However, the hip may be given additional years of functioning through the use of excision arthoplasty, or femoral head and neck ostectomy (FHO). The femoral head and part of the femoral neck is removed and the bone smoothed down so that bone-to-bone contact does not occur. In this state, the hip is referred to as a “false joint” and scar tissue is allowed to form around the end of the bone during the recovery phase.

Before and after views of a cat treated for hip dysplasia. Note the removed hip ball joints in the x-ray to the right.

This procedure is well-tolerated in cats and the complications (besides inflammation and infection) are few. It can also be used in the event of an accidental fracture to the femur. A lot of time and effort is required of the pet owners during recovery, since the patient will not be able to walk to move until the bone grows back. Because of the effectiveness of FHO, cats do not typically undergo total hip replacement surgeries.

Knee Replacement

There is currently no knee replacement surgeries being practiced in veterinary medicine for cats. However, an arthoplasty technique similar to FHO can be done if the need arises.

Cats have A, B, and AB blood types with specific factors, but there is no universal donor type. Type A is the most common blood type, and AB occurs extremely rarely in all breeds. Since there is no universal donor,, it is crucial that donor and recipient are properly cross-matched. Cross-matching is performed each time if multiple transfusions occur, since the recipient's immune system might build up resistance to the repeat donor.

There are two types of cross-matching tests, major and minor cross-matching. Red cells from the donor are mixed with the serum of the recipient in major cross-matching. In a minor cross-match, the recipient's red cells are compared with the donor's serum. If there are incompatibilities in minor cross-matching, only portions of the donor's blood may be transfused. These can be easily separated by centrifugation.

Cat donors are tested to make sure blood levels are high enough, and they also must meet a 10 lb. weight requirement. Other qualifications include:

• 1 to 8 years of age
• Indoor only
• Pass a health screen (exam, CBC and Chemistry panel)
• Must be FIV/FeLV negative
• Have proof of current vaccinations
• May not be on any medications (antibiotics, steriods) at the time of donation
• Has not received a blood transfusion before

Felines require sedation or anesthesia for safe blood donation. The blood is harvested from the jugular vein, usually a volume of about 55 mL. Most veterinary hospitals maintain a pool of clinic/staff-owned cats to provide a blood store. There are a few blood banks available in major cities that compensate owners for their donations, such as The Emergency Clinic for Animals or The UT College of Veterinary Medicine.