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Understanding Organ Matching: Ensuring the Right Match for Transplants

Organ transplants — like liver, kidney, pancreas and heart transplants — take an organ from a living or deceased donor and transplant it into someone with a dangerous or life-threatening health issue, giving them a chance to live a longer, better life.

Finding the right match is one of the most important things about organ transplantation. That means finding an organ from a donor that’s most likely to work well for the recipient. Health care professionals have to review lots of different factors to make the best match. 

We connected with Robert Harland, MD, a transplant surgeon, and Aneesha Shetty, MD, a transplant nephrologist, both with Banner – University Medicine, to understand more about how the process works and what makes a good organ match.

The organ transplant waiting list

There are nationwide lists of people who need organ transplants, called the rank list. “It’s not a list for a particular institute or transplant program. It’s individual patients,” Dr. Harland said. 

In general, as people wait longer for a transplant, they move up the list. However, some factors can influence a person’s position on the list. For example, an organ may go to someone nearby rather than someone across the country, since the organ might work better if it’s transplanted more quickly.

Here are some of the key points experts consider when matching organs with patients.

Tissue type matching and genetic compatibility

Tissue type matching checks specific antigens in tissues, including the human leukocyte antigen (HLA) system. Closer matches have less risk of rejection and mean the transplant is more likely to succeed, although modern immunosuppressive drugs can prevent or treat rejection episodes in most patients.

HLA system compatibility

The main factor that experts need to consider in organ matching for kidney and pancreas transplants is the HLA system. That system is a set of proteins on the surface of the donor organ’s cells that can cause the recipient’s immune system to reject the donated organ.

You can become sensitized to HLAs if you’ve already had an organ transplant, you’ve had a blood transfusion or you’ve been pregnant. If you received an organ with HLAs that you were sensitized to, your immune system would likely reject it. So, you wouldn’t be matched with those organs.  

Experts can estimate the wait time based on how often a tissue type they could react to is found in the general population. “We have some people who are 99.9% sensitized. They are pretty hard to match, and they might wait a long time,” Dr. Shetty said.

Looking for swaps may help shorten the wait time. For example, Dr. Harland recently removed a kidney from a donor and sent it to New York, and a transplant team in New York removed a kidney and sent it to Arizona. “Swaps have really been a boon to get more highly sensitized patients transplanted,” he said.

Blood type compatibility

Patients and donors need blood types that can work together so the patient doesn’t have a negative reaction or reject the transplanted organ. Your blood type can affect your wait time for an organ.

For example, about 15% of people have blood type B, but it’s more common in African Americans. “When I was a transplant surgeon in Chicago, about 70% of our waitlist was African American. But the donor population we were pulling from was only 15% blood type B,” Dr. Harland said.

You may have also heard that blood type O is universal, meaning it works for everyone. That’s true but in general, people with blood type O are matched with others with blood type O. That helps keep people with blood type O from waiting longer than others for a donor organ.

Size and weight considerations

When patients and donors are closer in size and weight, complications are less likely and organs are more likely to function well. It can be hard to stay healthy when you’re waiting for an organ, but it’s important to try not to gain too much weight. That’s because sometimes it’s not possible or safe to transplant an organ into someone with a BMI of 40 or more.

The quality of the organ

“We look for about 25 different potential infections that could be transmitted to the recipient with the transplant,” Dr. Harland said.

In some cases, recipients can decide what risk they’re willing to face with a donated organ. For example, hepatitis C can be transmitted through an organ transplant. 

“We have pretty good medications that can eradicate the hepatitis C, so patients often choose to accept a hepatitis C positive donor organ, knowing that they will possibly get the transplant sooner and hepatitis C can be treated,” he said.

The appearance of the organ

“A big part of the assessment is what the organ looks like in the operating room,” Dr. Harland said. A pathologist can take a small sample of an organ, especially a liver or kidney, to review it before it’s offered to transplant centers. 

Organ function

Experts can put kidneys, livers and hearts on pumps to see how fluid flows through them. “You can put the heart on a machine and actually measure how strong the heartbeat is,” Dr. Harland said. “You can measure the metabolism of the liver.”

Options for hard-to-place organs

Sometimes, people don’t want to accept organs from older donors. Transplant centers can find alternatives. For example, a younger recipient might decline a kidney from an older donor. But in some cases, a transplant surgeon can put both kidneys from that donor into one recipient, giving that patient enough function and longevity. 

“The data shows that these older kidneys have a survival equivalent to a 40-year-old donor single kidney because you put more functional kidney tissue in,” Dr. Shetty said.

The transplant team

A team of health care specialists works together on the transplant team to help every patient get the care they need and make sure they get an organ that’s the right match. The team may include transplant surgeons, nephrologists (kidney specialists), immunologists, transplant coordinators, nurses, pharmacists and other experts.

People waiting for an organ should ask questions and share their concerns with the transplant team members. The team should provide clear information and include the patient in making decisions. 

Navigating the waiting period

People may spend a lot of time waiting for organs. The type of organ someone needs and how likely it is to be a match can factor into the wait time. 

“Kidney is one of the longest. In the United States, 100,000 people are waiting for a kidney, and there were 35,000 kidney transplants performed last year,” Dr. Harland said. 

You can find detailed information on transplant wait times at the Scientific Registry of Transplant Recipients.

People may feel hopeful, excited, anxious or impatient while waiting for the call that an organ might match. “It’s hard. We generally see people on the wait list at least every six months, and part of that is to reassure them,” Dr. Harland said.

To cope during this time, it can help to:

  • Build a support system: Surround yourself with friends and family who understand you and can encourage you.
  • Stay informed: Knowledge is empowering. Know how the organ transplant process works and what the timelines are like.
  • Try stress-reducing techniques: Deep breathing, meditation or mindfulness may help you feel calmer.
  • Have realistic expectations: Recognize that the waiting period isn’t the same for everyone.
  • Distract yourself: Activities and hobbies like reading, listening to music or trying creative activities may improve your emotional well-being.

If you’re having trouble coping as you wait, you may want to connect with professional counselors, support groups and patient advocacy organizations that offer resources, guidance and a place to connect with others going through experiences like yours.

Finding a donor

For people waiting for a liver or kidney transplant, finding a living donor can speed up the process and increase the odds of success. “An organ from a living donor is almost always better than any deceased donor because it comes from a healthy person,” Dr. Harland said.

You never know who might be willing to donate an organ. “Have a short, persuasive summary ready about your need,” he said. A lot of people also have a friend or family member act as an ambassador and speak on their behalf. 

The bottom line

Experts consider many factors when they are finding the right organ to match with the right patient. The better the match, the more likely the transplant will succeed. 

If you would like more information about organ transplants, reach out to an expert at Banner Health.

If you want to learn more about possibly donating an organ, check out the information at Organ Donor

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