What's new in kidney transplants?

Kidney failure is a life-threatening condition faced each year by a growing number of Filipinos. When kidney failure reaches end-stage kidney disease, the only treatment options are dialysis or a kidney transplant.

Demand for a kidney transplant is considerably higher than for any other organ. Many people continue to be on the waiting list to have a kidney transplant. Fortunately, advances in kidney transplant procedures have expanded options for suitable donor kidneys in recent years. As a result, specialized transplant centers are now capable of performing successful kidney transplants that only a decade ago would have been thought impossible.

Faltering filters

Normally, every time your heart beats, about a fifth of your blood is diverted from the body’s largest artery (aorta) into your kidneys. There, wastes are removed and precise concentrations of water, salts, and other substances in your blood are regulated before that blood is returned to the heart for recirculation. Of the 50 gallons of blood pumped through your kidneys each day, about half a gallon of waste products and excess water are passed out of your body as urine.

Healthy kidneys manage all of this with ease. However, if an underlying disorder, such as diabetes or high blood pressure (hypertension), is destroying your kidney’s filtering units (nephrons), your kidneys begin to fail and become less efficient at doing their job.

For some, kidney failure can be managed with dietary changes, medication, and treatment of the underlying disorder. But if the kidneys still can’t perform their vital role of removing enough waste and fluid from the body, the next treatment option for end-stage kidney disease is typically dialysis or a kidney transplant.

Transplant options

In the past, age could be a roadblock when it came to donating a kidney or receiving a kidney transplant. Today, there are no absolute age restrictions for receiving a kidney transplant. However, to receive a kidney if you’re over age 65, your health must be relatively good, aside from the kidney disease for which the transplant is being sought.

A single donated kidney can accomplish most of what a previously healthy pair of failed kidneys used to do. A living-donor kidney transplant can be the best option if a matching donor can be identified — generally, a donor who is a blood relative can provide a closer match. However, very good results can also be obtained with kidneys from living donors who are unrelated — such as spouses, in-laws or friends. Short of a living donor, the next option may be to get on a waiting list for a kidney from a deceased donor. However, the wait can be several years or longer.

Fortunately, advances in kidney transplant procedures are making transplants possible for people who previously wouldn’t have been considered good transplant recipients due to the likelihood of organ rejection. A vital piece in these advances has been discovering ways to overcome antibody barriers that would otherwise lead to rejection of a transplanted donor kidney.

Normally, antibodies help your immune system identify and fight off foreign bodies, such as bacteria and viruses. In the case of a transplanted kidney, the kidney recipient’s antibodies can be directed against other proteins such as those that determine blood type or special proteins — particularly human leukocyte antigens (HLA) — that may be part of the transplanted kidney tissue. Two techniques that have improved transplant results by removing antibodies are:     

• ABO incompatible living-donor kidney transplant. ABO incompatibility refers to the immune reaction that occurs when different blood types — types A, B or O — are mixed together. Ideally, the kidney donor’s blood type is compatible with the transplant recipient’s. If there’s not a match, this living-donor transplant technique involves preconditioning the transplant recipient’s blood by cleansing it of antibodies. Preconditioning may include removing antibodies that cause rejection by filtering the blood (plasmapheresis), or by taking drugs that impair or decrease antibody activity. The transplant recipient’s antibodies are carefully monitored the first two weeks after transplant. If antibody levels get too high, additional plasmapheresis may be done.

• Positive crossmatch kidney transplant. When it’s determined that an intended transplant recipient carries antibodies that would attack the donated kidney, it’s called a positive crossmatch, and it makes organ rejection likely. However, performing blood preconditioning techniques, similar to those used with ABO incompatible transplants, makes it possible for some positive crossmatch transplant to be successful.

By receiving either an ABO incompatible or positive crossmatch living-donor transplant with proper blood preconditioning techniques, recipients can have a lower risk of rejection than would have previously been expected and thereby avoid being on the kidney transplant waiting list for several years. Success rates of ABO incompatible transplants are nearly equal to those done with blood-type-compatible recipients, and positive crossmatch kidney transplants have similar success rates to transplants of deceased-donor kidneys.

LIVING-DONOR KIDNEY DONATION

Living kidney donors typically range in age from 18 to 70, are in good health, and — based on a pre-evaluation process — have normal kidney function and anatomy. Certain health conditions can rule out a live kidney donation, including diabetes, some cancers, intravenous drug use, and certain infectious diseases, such as hepatitis and AIDs.

For someone who meets the donor criteria, donating one kidney will continue to do its job normally and will compensate for the loss of the other kidney. In fact, a recent study shows that people who give kidneys to others not only have a normal life span but also have fewer kidney problems than does the general population — perhaps because they were healthier to start with.

After surgical removal of the kidney (nephrectomy), there’s no routine need for drugs or intense restriction on diet for the donor.

The nephrectomy may be done in one of two ways:

• Laparoscopic donor nephrectomy (see illustration on Page D-1). With the help of a scope, the surgeon locates, secures, and removes the kidney through a small incision in the abdomen. This procedure allows for a faster recovery, and has become the preferred approach at many leading medical centers abroad. Typically, two days are spent in the hospital and normal activities can be resumed within about three weeks.

• Traditional donor nephrectomy. This involves making a larger incision on one side of the back through which the kidney can be removed. After this operation, kidney donors remain in the hospital for four to six days and can usually resume normal activities in five to six weeks.

Most living-donor kidneys begin functioning immediately after transplantation with fewer complications than those from deceased donors. Living-donor kidneys also tend to last longer than do deceased-donor kidneys. Generally, half of the living-donor kidneys are still functioning 25 years after transplant, whereas half of deceased-donor kidneys fail in the first 10 years after transplant.

After your surgery

After a kidney transplant, you can expect an additional three to four weeks of very close monitoring from your doctors. Even with the best possible match between you and the donor, your immune system will try to reject the new kidney.

Organ rejection may occur at any time after a transplant, but most occur within the first few weeks or months. Immuno-suppressive drugs are used immediately after the transplant and for the rest of your life to prevent rejection. Other drugs may also be prescribed to help your body fight off infections. In addition, you’ll need to follow a post-transplant diet that’s low in fat, sugar, and salt.

A kidney transplant offers no guarantees. Frequent blood tests during the first year after transplant are necessary to monitor how your body is accepting the new kidney.