Kidney transplantation offers a new beginning for people whose kidneys have stopped working properly, providing an opportunity to regain energy, freedom, and a better quality of life than dialysis can offer.

Understanding Kidney Transplantation

A kidney transplant is a surgical procedure where a healthy kidney from a donor is placed into the body of someone whose kidneys no longer function properly. The kidneys are two bean-shaped organs, each about the size of a fist, located on either side of the spine just below the rib cage. Their main job is to filter and remove waste, minerals, and fluid from the blood by producing urine. When kidneys lose this filtering ability, harmful levels of fluid and waste collect in the body, which can raise blood pressure and lead to kidney failure, also known as end-stage renal disease.^[1]

End-stage renal disease happens when the kidneys have lost about 90% of their ability to work properly. Common causes include diabetes, ongoing uncontrolled high blood pressure, chronic inflammation and scarring of the tiny filters within the kidneys (called glomerulonephritis), lupus nephritis, and polycystic kidney disease. People with end-stage renal disease need to have a kidney transplant or dialysis (a treatment that removes waste from the bloodstream using a machine) to stay alive.^[1]

During the transplant surgery, the donated kidney is placed in the lower abdomen, either on the right or left side. The blood vessels of the new kidney are connected to blood vessels in the lower part of the abdomen, just above one of the legs. The new kidney’s urine tube, called the ureter, is connected to the bladder. Unless they are causing complications, the person’s own kidneys are usually left in place.^[1]

Epidemiology

The number of kidney transplants performed each year in the United States has been steadily rising. In 2022, surgeons performed more than 25,000 kidney transplants, which represented a 3.4% increase compared to 2021. This was the first time the total number of kidney transplants in the United States exceeded 25,000 in a single year.^[5]

According to the United Network for Organ Sharing, the survival rates for kidney transplants have improved significantly over time. The one-year survival rate for kidney transplants is approximately 95%, while the five-year and ten-year survival rates are about 85% and 65%, respectively. Patients with end-stage renal disease who are placed on the waiting list and eventually undergo kidney transplantation have better long-term survival compared to those who stay on dialysis. Furthermore, those who undergo transplantation often experience a better quality of life and a projected survival benefit of 10 years over those who remain on dialysis.^[3]

Causes

Kidney transplants are performed to treat people with chronic kidney disease or end-stage kidney failure. When the kidneys can no longer filter waste properly, either dialysis or a kidney transplant becomes necessary.^[5]

The underlying conditions that damage the kidneys and lead to the need for transplantation vary widely. Diabetes is one of the most common causes, as high blood sugar levels over time can damage the small blood vessels in the kidneys. Ongoing, uncontrolled high blood pressure is another major cause, as it puts stress on the blood vessels in the kidneys and throughout the body. Chronic inflammation of the kidney’s filtering units, known as glomerulonephritis, can lead to scarring and loss of function. Other causes include lupus nephritis (kidney damage caused by the autoimmune disease lupus) and polycystic kidney disease (a genetic disorder where cysts grow in the kidneys).^[1]

Risk Factors

Not everyone with end-stage renal disease is eligible for a kidney transplant. Each hospital has its own criteria for accepting people as kidney transplant recipients. In general, candidates for kidney transplant should have end-stage renal failure and be on dialysis, or have chronic kidney disease with a glomerular filtration rate (a measure of kidney function) less than or equal to 20 mL/min. Candidates need to have a full understanding of postoperative instructions and care, and should be in good overall physical and mental health with strong social support.^[5]

There are factors that could make a person ineligible for a kidney transplant. These include having a serious health condition, certain infections, cancer or a history of cancer, certain mental health conditions, poor social support, a short life expectancy, or a history of not following medical advice. While there is no strict age limit, most facilities accept people who are 17 years old and older. The evaluation focuses more on meeting the medical and psychosocial criteria than on age alone.^[5]

Symptoms

The symptoms that lead someone to need a kidney transplant are actually the symptoms of kidney failure itself, not of the transplant. When the kidneys fail, harmful levels of fluid and waste collect in the body. This can cause a range of problems including high blood pressure, swelling in the legs and ankles, difficulty breathing, fatigue, nausea, loss of appetite, confusion, and changes in urine output. These symptoms gradually worsen as kidney function declines, significantly affecting a person’s ability to carry out daily activities and maintain their quality of life.^[1]

After receiving a kidney transplant, most patients experience a dramatic improvement in how they feel. Many notice increased energy levels and a reduction in the symptoms that had been affecting them while on dialysis. However, recovery takes time, and it’s normal to feel tired during the healing process. It may take three to six weeks for energy to fully return. The abdomen and side will be sore for the first one to two weeks after surgery, and there may be some numbness around the surgical cut.^[21]

Prevention

While there is no way to prevent the need for a kidney transplant once end-stage renal disease has developed, there are steps that can be taken to protect kidney health and delay the progression of kidney disease. Managing underlying conditions is crucial. For people with diabetes, keeping blood sugar levels under control through diet, exercise, and medication can help prevent kidney damage. Similarly, maintaining healthy blood pressure through lifestyle changes and medication when necessary can protect the kidneys from damage caused by high blood pressure.^[1]

After receiving a kidney transplant, preventing rejection (when the body’s immune system attacks the new kidney) becomes the primary focus. This requires taking anti-rejection medications, also called immunosuppressants, every day for as long as the transplanted kidney is functioning. These medications work by suppressing the immune system so it doesn’t attack the new kidney. Missing doses or stopping these medications can lead to rejection and potential loss of the transplant. Patients must also take steps to avoid infections, since the immunosuppressant medications make the body less able to fight off germs.^[11]

Maintaining a healthy lifestyle after transplant is essential for long-term success. This includes following a balanced diet that is low in salt to help control blood pressure, staying physically active with regular exercise, maintaining a healthy weight, and avoiding smoking and excessive alcohol consumption. Regular checkups with the healthcare team and prompt attention to any warning signs are also critical components of prevention after transplant.^[18]

Pathophysiology

In a healthy person, the kidneys work continuously to filter blood, removing waste products and excess fluid while keeping important substances like proteins and blood cells in the bloodstream. Each kidney contains about one million tiny filtering units called nephrons. When kidney disease progresses to end-stage renal disease, the vast majority of these nephrons have been damaged and can no longer function. This means the body can no longer effectively remove waste products, maintain proper fluid balance, or regulate important minerals and electrolytes.^[1]

During a kidney transplant, a healthy kidney from a donor takes over these vital functions. The new kidney may start working very soon after surgery, or it may take a few weeks. In some cases, the newly transplanted kidney goes through a phase called “delayed graft function,” which could last from a few days to many weeks. During this time, if the kidney has a good blood supply, doctors generally remain optimistic. However, there might be treatable reasons for the delay, so sometimes a kidney biopsy (a procedure where a small piece of the kidney is removed and examined under a microscope) is performed to check for rejection, viral illnesses, or other issues.^[23]

The immune system naturally recognizes the transplanted kidney as foreign tissue and tries to attack it. This is why immunosuppressant medications are essential. These drugs work through various mechanisms to reduce the activity of the immune system, preventing it from mounting a full attack on the new kidney. The balance is delicate because while the immune system needs to be suppressed enough to prevent rejection, it also needs to maintain some function to protect against infections and cancer. Different immunosuppressant medications target different parts of the immune response, which is why patients typically take a combination of two or three different drugs.^[11]

After transplant, patients may notice swelling around the legs and groin area. This typically settles as the kidney starts passing good amounts of urine. The transplanted kidney is usually placed in the lower abdomen rather than in the natural position of the original kidneys because this location makes it easier to connect the blood vessels and ureter, and also makes it more accessible if any problems arise that need to be addressed surgically.^[1]