Kidney transplantation

Section editor: Keith Graetz, Consultant Transplant Surgeon, Portsmouth

What the kidneys do
The kidneys function to control the balance between the amount of water that the body holds and also many important chemicals that are vital for its efficient functioning. Sadly for some patients, they fail during their life leaving the patient needing dialysis or transplantation for their survival. There are many conditions that can result in kidney failure. Some of these are inherited, like polycystic kidney disease, whilst others occur as a consequence of other conditions, like diabetes.

Dialysis
Without a kidney transplant, a patient with kidney failure will either die or need dialysis. For haemodialysis to be performed patients will usually have had surgery to join an artery to a vein (AV fistula). The AV fistula is “needled” allowing blood to pass through a machine where it is filtered and returned to the patients’ circulation. Some patients will dialyse using a plastic tube (central venous catheter) that has been inserted into a large vein (usually in the neck). Haemodialysis usually requires three dialysis sessions a week lasting four hours at a time. Peritoneal dialysis involves a plastic dialysis tube being inserted into the abdominal cavity. Dialysis fluid is then put into the abdominal cavity and left for a period of time before being drained out. This process is repeated continually by a machine overnight whilst the patient is asleep (APD) or done up to four times a day manually by the patient (CAPD).

Donation
Kidneys are donated by patients who have either passed away (deceased donor) or have offered one of their own healthy kidneys (live donor) to a potential transplant recipient. Deceased donors will have either given permission for their organs to be donated prior to their death or permission for donation will have been given by the next of kin. This is made much simpler if a patient has registered on the organ donor register as it allows the transplant team to understand a patient’s wish once they have died. A live donor is usually a spouse (live unrelated donor) or a close family member (live related donor) who has come forward with an offer of a kidney. Occasionally, donors come forward offering a kidney for a recipient who they have never met and have no emotional relationship with (altruistic live donor). Live donation allows a date to be set for the transplant and for everyone involved to plan for this time.

Assessment
In order to be considered for transplantation a patient needs to be assessed by their medical doctor (nephrologists) and the kidney transplant surgeon. Not all patients will be deemed fit enough to be put forward for transplantation as there medical condition may mean that the risks of surgery are too great. However, it should be considered as an option in all those patients between the ages of two and 80.

Compatibility and immunosuppression
Before a kidney is deemed suitable for a specific recipient many tests need to be done. The most important ones include a blood group compatibility test and a “cross match”. The latter blood test ensures that the recipient will not “reject” the kidney as soon as the operation is finished. To further reduce the chances of this happening the patient will need to take tablets that suppress their immune system for the rest of their life e.g. ciclosporin, prednisolone, Tacrolimus etc.

Surgery
Once a suitable kidney is offered from either type of donor the transplant recipient has to undergo major surgery to have the kidney implanted. This is done under general anaesthesia and will usually take about two hours. An incision is made in the groin and the kidney is attached to the main artery and vein at this site and the tube draining urine (the ureter) is attached onto the top of the bladder. Afterwards the recipient will hopefully no longer need dialysis and will make a rapid recovery allowing them to be discharged from hospital about a week after the operation. Patients have to take many tablets, including immunosuppression tablets, and attend the out patient department for regular check ups following their discharge. Kidney transplantation should therefore not be thought of as a cure for kidney failure, merely as a form of treatment and whilst there are risks involved, the long-term benefits of transplantation far out weigh the relative security that dialysis offers!

The first kidney transplant was done in Boston, USA, in the 1950s and since this time great advances have been made. The average deceased donor kidney survives for 12 years and a live donor kidney for 15 years. Outcomes can be further improved by transplanting the patient with kidney failure before they ever need dialysis (pre-emptive transplantation). Kidney transplantation remains the best form of treatment for kidney failure improving both the quantity and quality of life of the patient affected.