New liver transplant rules found to cut waiting list deaths

The United Network for Organ Sharing tweaked the system for livers and revised tissue-matching policy for kidneys, which will likely increase transplants among minorities.

By Susan J. Landers, amednews staff. Dec. 2, 2002.

Washington -- A new system to prioritize liver transplant candidates more objectively has worked well during its first six months, although some refinements were called for, according to United Network for Organ Sharing, which operates the national Organ Procurement and Transplantation Network for the federal government.

The OPTN/UNOS board met in November to approve those refinements and to ease the way for more minority patients to receive kidneys.

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Since the new liver allocation system was implemented, the number of patients who either died while on the waiting list for a liver or were removed from the list because they were too sick to undergo a transplant dropped by 23%, said UNOS.

The early data also suggest that under the new system there was either no change or a slight improvement in patient survival rate after transplantation. If that trend continues it would put to rest a fear held by some that since sicker patients would be receiving the organs, their outcomes were less likely to be positive.

"While these results are preliminary, they are encouraging," said Richard Freeman, MD, chair of OPTN/UNOS Liver and Intestinal Organ Transplantation Committee. "These early results suggest that the policy is meeting the key goal of reducing wait list deaths," he said.

The group examined data available from Feb. 27, when the updated system was implemented, until Aug. 27.

5,200 liver transplants were performed in 2001, but 17,000 people were on the waiting list.

Under the new allocation system, called the Model for End-Stage Liver Disease, or MELD, and Pediatric End- Stage Liver Disease, or PELD, common, objective laboratory tests are used to rank patients on a continuous scale of severity of illness.

The new system replaced three of the four categories of transplant status that had been used previously.

Only the highest priority, status one, remains.

Patients with higher MELD or PELD scores are judged to be at greater risk of death if they don't receive a transplant and, therefore, are given higher priority for available donor livers.

An analysis of the system's first six months also revealed the need for an adjustment for people with hepatocellular carcinoma.

The majority of patients with HCC had received higher priority for a transplant because of their cancer. In the first six months of the new system, those with HCC received about 21% of the transplants, a number higher than was likely warranted.

To correct that situation, the UNOS Board of Directors voted on Nov. 14 to lower the priority status granted to HCC patients. "We have found upon early review that the priority for HCC liver candidates was not in proportion to that of candidates with other diagnoses," said Dr. Freeman.

"We may have overshot the mark," he said prior to the board's decision. "We don't know how fast HCC progresses, so it is difficult to determine how much priority to give [it]."

Additional adjustments are also possible, said Dr. Freeman. "Nothing is written in stone."

Problems resolved

The MELD system was developed to help resolve a dilemma over how to fairly distribute the organs to patients awaiting liver transplantation. A controversy had been touched off by a 1998 federal proposal that called for abolishing geographic restrictions for distributing organs.

The new system is thought to be fairer because it relies on objective measures of a patient's condition. The old system favored using organs in closest proximity to where they were donated. States that had worked hard at encouraging higher donation rates were loath to allow the scarce organs to benefit a patient in a distant state that had lower rates of donations.

In 2001, for the first time, living organ donors surpassed the number of deceased donors.

There were about 5,200 liver transplants performed last year, noted Walter Graham, UNOS executive director, but there were more than 17,000 people on the waiting list.

The old system also gave priority to patients who had been on waiting lists for the longest time. This practice led to many transplant centers immediately placing a patient on the waiting list to better ensure that an organ would be available for them when they needed it. The tactic was thought to put sicker patients with less access to health care at a disadvantage.

The length of time a person has been on a waiting list is now only used to break a tie among two equally sick patients, said Dr. Freeman.

In other developments, the UNOS board voted to eliminate some of the importance attached to human leukocyte antigen matching between organ donor and recipient to make it easier for blacks and Hispanics to receive kidneys.

Although a close HLA match lowers the chances for rejection, it also stands in the way of more organ matches for minority patients, said Winfred Williams, MD, chair of OPTN/UNOS minority affairs committee. While most donors are white, most kidney recipients are black or Hispanic, said Dr. Williams.

Acknowledging that the proposal could increase the possibility of organ rejection, Dr. Williams noted that improvements made in recent years in treating organ rejection were likely to offset that possibility. The change is expected to allow more than 200 additional kidney transplants annually for minority patients.

UNOS has also established a committee to consider issues surrounding living donors. In recent years, living donor transplants have increased at a much higher rate than transplants from deceased donors. In 2001, for the first time, the number of living organ donors, at 6,530, surpassed the number of deceased donors, at 6,082.

The new Ad Hoc Living Donor Committee is developing plans to track the postdonation progress of living donors to address such issues as how soon they were able to return to work, financial incentives or disincentives, and ethics.