Kidney Transplant: Types, Donor Matching, and Documents Required

10 October,2024

The kidneys are two bean-shaped, fist-sized organs located in the retroperitoneal site on either side of the spine. They are vital organs, and humans cannot survive without at least one healthy, functioning kidney. Kidneys perform several important functions in the body. Their primary function is to eliminate waste through urine by filtering toxins and waste products from the blood. They also regulate body fluids and blood pressure and maintain electrolyte and acid-base balance. When the kidneys fail, all these functions are affected, accumulating harmful toxic substances in the body. The treatment for kidney failure is either dialysis or a kidney transplant.

Kidneys are the most transplanted organs in the human body. In 2022, around 65% of the total organ transplants in the world were kidney transplants. Surgeons Joseph Murray, J. Hartwell Harrison, and their team conducted the first successful kidney transplant on a pair of identical twins. In the last decade, the rate of kidney transplants worldwide has grown from 11 per million population to 17.1 per million population. The United States of America, Spain, and Mexico have the highest rates of kidney transplants. Other popular countries for kidney transplant surgeries include India and South Korea.

This blog explores the kidney transplant procedure, the conditions it treats, and other in-depth information.

What is a Kidney Transplant?

A kidney transplant surgery is a procedure where a healthy, functioning kidney obtained from a donor is placed in a patient whose kidneys are not functioning adequately. It is also known as a renal transplant. When both kidneys of the patient fail, a kidney transplant or dialysis are the only treatment options. Usually, a person will need just one healthy kidney from a donor to survive. In rare cases, two kidneys might be transplanted in the same patient.

How Does a Kidney Transplant Differ from Dialysis?

When a person's kidneys cannot filter the blood to eliminate toxins and waste, an artificial machine does the filtration for them. This process is known as kidney dialysis or renal replacement therapy. Patients have to undergo dialysis for the rest of their lives. It is also expensive and tiring as patients have to visit a dialysis facility or purchase costly equipment to use at home.

A kidney transplant uses a donor kidney to replace the malfunctioning kidneys and perform their functions. It is a comparatively long-term solution for kidney failure. It also offers benefits such as a better quality of life, higher life expectancy, fewer dietary restrictions, lower risk of complications, and a lower cost of treatment.

While both procedures are accepted methods of treating kidney failure, kidney transplants are often the treatment of choice. However, not all patients with kidney failure are eligible for a transplant.

Why are the Types of Kidney Transplants?

The doctor decides the type of kidney transplant based on the patient's health, the cause of kidney failure, and organ availability. There are three main types of kidney transplants:

• Deceased-donor Kidney Transplant: In a deceased-donor kidney transplant, the donor kidney comes from someone recently deceased. They can be a pre-registered organ donor, or their family can decide to donate their organs after their death. The kidney received from a deceased donor takes a bit longer to regain normal function after transplantation. To become eligible for a deceased-donor kidney transplant, the patient has to go on a transplant waiting list. A deceased-donor kidney transplant is the most common type of kidney transplant.
• Living-donor Kidney Transplant: When a living person donates their kidney to a patient with kidney failure, it is known as a living-donor kidney transplant. As humans can survive with just one kidney, a person can donate one of their healthy kidneys and still live a normal life. Living donors are usually immediate family members, relatives, friends, or acquaintances. Sometimes, strangers can also become living donors if they are a match. The waiting time for a living-donor kidney transplant is usually shorter than for a deceased donor transplant.
• Preemptive Kidney Transplant: Sometimes, patients with kidney failure undergo a kidney transplant before needing dialysis. This method is known as a preemptive kidney transplant. It is a rarely practiced method, but it has several benefits. It lowers the risk of organ rejection, improves the patient's quality of life, reduces treatment costs, and improves their life expectancy. Patients can avoid dialysis altogether after a preemptive transplant. However, preemptive transplants are not that common due to the shortage of kidney donors, delayed referrals to transplant centers, and lack of access to care.

Why is a Kidney Transplant Required?

A kidney transplant is the chosen treatment for patients with end-stage kidney disease or end-stage renal disease (ESRD) and chronic kidney disease (CKD), which cause kidney failure. Conditions that cause end-stage renal disease include: 

• Diabetes (both type 1 and type 2)
• Hypertension or high blood pressure
• Polycystic kidney disease
• Glomerulonephritis (inflammation of the kidney's filtering units, glomeruli)
• Interstitial nephritis (inflammation of the kidney's tubules and surrounding structures)
• Urinary tract obstruction due to enlarged prostate gland, kidney stones, or cancer
• Pyelonephritis (recurrent kidney infection)
• Autoimmune diseases such as lupus
• Hemolytic uremic syndrome (HUS)
• Vesicoureteral reflux (a condition where urine flows back up into the ureter from the bladder)

Certain other conditions may also require a kidney transplant, such as congenital kidney defects and acute kidney injury.

Is Kidney Transplant a Suitable Option for Everyone?

While a kidney transplant is a preferred choice of treatment for the disorders mentioned above, some situations may render a patient ineligible for a transplant, such as:

• Active or recurring infections, such as tuberculosis or hepatitis
• Severe heart disease
• Active or recent history of cancer
• Habits such as smoking, excess alcohol or drug consumption
• Advanced age and shorter life expectancy
• Liver disorders
• Any other conditions that make undergoing surgery risky

What are the Success Rates for Kidney Transplants?

The success of a kidney transplant will depend on several factors, such as the patient's age, health, severity of kidney disease, and post-treatment care. However, kidney transplants have generally high success rates. On average, the one-year survival rate is around 95%, and the three-to-five-year survival rate is approximately 90%. The success rates also vary according to the type of donor. The one-year survival rate for deceased-donor kidney transplants is 94.88%, and the kidney lasts for about 8 to 12 years. For a living-donor kidney transplant, the one-year survival rate is 98.11%, and the kidney lasts for around 12 to 20 years.

How are Donors and Recipients Matched for a Kidney Transplant?

Finding the right match between donors and recipients is imperative for a successful kidney transplant. If there is an organ mismatch, the chances of the body rejecting the new kidney increase, which will ultimately lead to transplant failure. Certain tests are conducted before the transplant surgery to confirm that the donor and recipient are compatible. These tests  include:

Blood Typing

It is ideal for the donor and recipient blood groups to be compatible. 

• A person with an AB blood group is a universal recipient and can receive a kidney from all blood groups but can donate only to someone with an AB blood group. 
• On the other hand, blood group O is a universal donor and can donate a kidney to patients of all blood groups but can only receive a kidney from blood group O.
• Those with blood group A can donate to blood groups A and AB and receive a kidney from blood groups A and O.
• A person with blood group B can give their kidney to blood groups B and AB and receive a kidney from blood groups B and O.

Kidney transplants between incompatible donors and recipients are also possible through paired kidney transplants. In this method, two pairs of living donors and recipients are matched so that each recipient is compatible with the donor in the other pair. The donors then donate their kidneys to the recipients in the other pair.

For a direct transplant between incompatible blood types, the recipient has to undergo treatment for the removal of blood group antibodies to minimize the risk of rejection.

Human Leukocyte Antigen (HLA) Typing

If the recipient and donor blood groups match, another test, the human leukocyte antigen (HLA) test or tissue typing test, is conducted.

• This test compares the donor and recipient antigens to find a match. Antigens are markers on the cells that help the body differentiate between self and non-self.
• The recipient's body recognizes the new kidney as a foreign object and attacks it, which may cause the transplant to fail.
• Therefore, HLA typing is necessary to judge the probability of a successful transplant by determining the degree of mismatch.
• A good HLA match will help in reducing the chances of organ rejection.
• Identical twins are the best HLA match, followed by siblings and parents. It is rare to find an unrelated donor with an exact HLA match.

Cross-matching

Cross-matching is the final compatibility test between the donor and recipient before the transplant surgery.

• In this test, a small amount of blood from the donor and recipient is mixed in a laboratory to check how the recipient's cells react to the donor's cells.
• If the recipient cells attack donor cells, it is a positive crossmatch, which implies a higher chance of organ rejection.
• If the recipient cells do not attack donor cells, it is a negative crossmatch, which means the chance of organ rejection is lower. 
• A negative crossmatch is the ideal situation for a successful kidney transplant.

In addition to blood grouping, HLA typing, and cross-matching donors and recipients are matched based on age, geographical location, and kidney size.

What is the Procedure for a Kidney Transplant?

When a kidney donor becomes available, the hospital will contact the patient to set up surgery. For living donor transplants, the donor and recipient can plan their surgeries beforehand.

Before the Surgery

The doctor will explain the entire kidney transplant procedure to the patient before the surgery. They will also conduct some tests to ensure the patient is fit for surgery. The tests include:

• Complete physical examination
• Psychological examination
• Blood tests
• X-rays, CT scans, ultrasounds, and MRIs
• Kidney biopsy

During the Surgery

• The surgeon will put the patient under general anesthesia for the procedure.
• The surgeon will sterilize the surgical site and make an incision in the lower abdominal area on one side.
• Then, they will place the new kidney in the area.
• A right donor kidney will be placed on the recipient's left side, and the left donor kidney will be placed on the recipient's right side to provide easy access to the ureter.
• The recipient's non-functioning kidneys are usually left in their place unless there is a particular medical reason to remove them.
• The surgeon will connect the blood vessels to the new kidney and ensure adequate blood flow. The new kidney's ureter is attached to the bladder.
• If there are no complications, the surgeon will close the incision with stitches, and the surgery will be complete.
• The surgery will usually take two to three hours to complete.

After the Surgery

• After the surgery, the patient has to remain in the hospital for about two weeks so that the doctor can monitor their vitals.
• In the case of a living donor transplant, the donor may have to stay at the hospital for about four to seven days.
• The patient will have a tube (catheter) inserted into their bladder for urine drainage. The doctor will monitor the urine output to ensure the new kidney functions.
• Usually, a kidney from a living donor starts working immediately, whereas a kidney from a deceased donor may take some time.
• The patient must take immunosuppressants lifelong to prevent the body from rejecting the new kidney.
• The patient might need to visit their doctor regularly for follow-up.
• The patient must watch for any complications, changes, or signs of rejection, such as fever, tenderness around the kidney, and redness.
• The recovery period depends on several factors, although it takes around six weeks to heal from a kidney transplant.

What are the Risks and Complications of a Kidney Transplant?

Like any other surgery, a kidney transplant comes with its risks and complications, such as:

• Rejection of the new kidney
• Failure of the transplant
• Leakage from the ureter
• Blockage of the ureter
• Infections, bleeding, and blood clots
• Heart attacks, stroke, or death

Apart from post-surgical complications, transplant patients may face side effects of immunosuppressants, such as diabetes, high blood pressure, bone thinning, excessive hair growth, high cholesterol, increased susceptibility to skin cancers and non-Hodgkin's lymphoma, infections, acne, and weight gain.

What Documents Are Needed for a Kidney Transplant?

Patients undergoing a kidney transplant and their donors must submit certain documents for approval. These documents include:

Documents for First Degree Relatives (Parents/Siblings/Children above 18 years/Grandparents)

• Donor and recipient's passport and medical visa
• National ID cards of donor and recipient
• Original birth certificates of donor and recipient
• Detailed family tree
• No Objection Certificate (NOC) from the donor's immediate dependents
• Declaration affidavits (in domestic language and translated into English) by donor and recipient
• Death certificates (if the donor or recipient's immediate dependents are dead)
• Letters from the Health Ministry
• Ten passport-sized photographs of each of the donor and recipient
• Two family group photographs with the donor, recipient, and their immediate family visible

Documents for Spousal Donation

For a kidney transplant between spouses, all documents for first-degree relatives must be submitted, along with marriage photographs, marriage certificates, and birth certificates of children, if any.

Documents for Second Degree Donations (Uncle/Aunt/Niece/Nephew/In-laws/Cousins)

• For second-degree donations, all documents submitted for first-degree donations are applicable, along with medical records and proof of why first-degree relatives are not available for donation. 
• They must also submit the donor and recipient's bank statement for the last three years and their occupational details if they work.

Medical Records Required From Donors and Recipients For a Kidney Transplant

The donor and recipient must submit essential medical records before a kidney transplant. These include:

• Donor: Blood group, urine analysis, glucose tolerance test, abdominal ultrasound, renal function tests, cross-matching, hepatitis B and C virus test (HBsAg and HCV antibody), HIV 1 and 2, height and weight
• Recipient: Blood group, renal function tests, HIV 1 and 2, echocardiography, abdominal ultrasound, hepatitis B and C virus test, ECG, cross-matching, height and weight

Takeaway

A kidney transplant is one of the treatments available for end-stage renal disease, chronic kidney disease, and kidney failure. It has several benefits over dialysis. Patients can receive kidneys from deceased or living donors. However, the procedure faces the challenge of donor shortage. New research is being conducted to overcome this challenge, and modern technology is being introduced worldwide. Thus, more patients with kidney disease can benefit from this life-saving treatment method.