Matching kidney quality, life span

Matching kidney quality, life span

Proposals on how to rank organs, assign them to patients

- Sabin Russell, San Francisco Chronicle Medical Writer
Monday, January 1, 2007

If you were offered a lower-quality kidney to shorten your stay on the organ transplant waiting list, would you take it?

Virginia Grimm was faced with that choice one year ago.

The source was a 51-year-old man who had died of a stroke -- a situation that automatically disqualified his kidneys as "standard" organs for donation. But under a special program to expand the pool of donors, they could be offered to qualified patients willing to take them.

Substandard kidneys can perform perfectly for many years, but on average they fail at much higher rates. Within five years, half of them no longer function and 30 percent of patients who receive them are dead.

Grimm, who was 59 at the time and had been living on dialysis for two years, opted for the lesser kidney. It was transplanted at California Pacific Medical Center in San Francisco on Dec. 29, 2005. She and her new kidney (transplant patients typically get just one organ) are doing fine.

"I doubt that I would be alive today, if I didn't get that kidney,'' the grandmother of 10 said from her home in Reno.

Grimm had known that her health was deteriorating. Technicians at her dialysis center were having trouble finding her veins when they hooked her up to the blood-cleansing machine. Dialysis was exhausting, and she was prone to infections. Another set of statistics also weighed on her mind: In the prior year, more than 4,000 patients with end-stage kidney disease died while waiting for transplants.

Substandard kidneys were once labeled "marginal," and, before that, "crumbs.'' The names themselves discouraged their use. Since 2002, when a new program set up national standards for such organs, they have been called "Expanded Criteria Donor" or ECD kidneys.

The program has been a modest success. About 15 percent of kidneys transplanted from deceased donors today are ECDs, according to the United Network for Organ Sharing, which sets national policy on transplantation.

But America's kidney transplant program needs something more than a modest success. Each year, the number of patients on the waiting list grows. There were 77,000 registered for kidney transplants during 2004, the most recent figures available, compared with nearly 42,000 in 1995 -- an 83 percent increase.

Faced with relentlessly expanding demand for transplants, and a perpetual shortage of kidneys to offer, policymakers are mulling over alternate ways of rationing this precious resource. One proposal, advanced by Stanford Business School Professor Stefanos Zenios, would establish at least three grades of kidneys. Patients would be required to declare in advance whether they would accept organs of one or both of the lower grades.

Computer models of the proposed system show it would boost the availability of kidneys for transplant by 10 to 15 percent, and decrease by 30 percent the number of patients who die on the waiting list.

Kidneys could be graded on estimates of "half-life," or the time it would take before 50 percent of the kidneys in the grade could be expected to fail. Age of the donor would weigh heavily in the half-life estimate, but other complex factors, such as time between donor death and transplant, would be factored into the formula. The top grade, labeled AAA, would have an estimated half-life of 13.5 years, and would come mostly from donors under 45 years of age. Grade AA kidneys, with a half-life of eight years, would tend to come from donors ages 45 to 55. Donors older than 55 would supply the grade A kidneys, with an estimated half-life of 5 years -- not much different from an ECD kidney today.

Patients at the lowest risk of dying while on the waiting list would likely choose grade AAA. The price of their choice would be a longer wait for a better kidney. Patients who had a high risk of dying would sign up for Grade A. Patients at a low risk of dying, but who did not want to extend their wait for a transplant, might opt for AA.

Allowing patients to declare in advance what grade of kidney they would accept, Zenios said, would speed the placement of lower-grade organs, which sometimes go to waste when patient after patient rejects the offered substandard kidney. According to United Network for Organ Sharing statistics, about 1 in 6 donated kidneys are ECDs, and 39 percent of these are discarded by surgeons as unsuitable for transplant. "By better matching patient to donor, it would make organ allocation more efficient,'' Zenios said.

But in an article describing his system in the journal Management Science, Zenios raises a potential problem. "The cost of transplanting kidneys of lower quality is substantially higher than the cost of high-quality kidneys,'' he wrote, citing a study showing the five-year medical costs for ECD recipients was $166,000, compared with $134,000 among recipients of standard kidneys.

Dr. Scott Nyberg, a transplant surgeon at the Mayo Clinic in Rochester, Minn., has proposed a system that would match a patient's anticipated future lifespan to one of four grades of kidneys, labeled A, B, C or D. In a study published in the journal Transplantation, he and colleagues found the reallocation increased the overall supply of kidneys by up to 22 percent.

The system for grading kidneys is complex, assigning points for donor age, cause of death, time since death, prior health of the donor and the levels of certain chemicals that are markers for the organ's efficiency. "It's not like going to the butcher shop and seeing a good cut of meat and saying, 'I want that,' '' said Nyberg. "You need lab tests, and a little bit of medical history."

Such a system could reduce a common tragic outcome: that younger recipients often outlive their kidneys and need a second or third transplant, while many older recipients die with a younger kidney still functioning inside them.

"The biggest waste of kidneys occurs when you give a young kidney to an older person,'' Nyberg said. "Everyone understands the potential benefit. If you can stop the growth of the waiting list, and turn it around, that would be tremendous."

But Nyberg's plan comes close to explicit rationing by age -- a step that raises troubling ethical questions. "People will jump up and say that a healthy 82-year-old can do better than an unhealthy 40-year-old,'' said University of Pennsylvania ethicist Arthur Caplan.

"Another concern is that when you offer choice to people, not everybody is equally empowered. People who don't read well, or don't have math skills, may not have the outcome of someone who can hire a game theorist to sit with them and consider choices," Caplan said.

Amid increasing concern over the growth of the kidney transplant waiting list, however, less patient choice may be in the offing.

American organ transplant policymakers are considering adoption of a new allocation system matching kidney grades to life expectancy. To preserve the healthiest kidneys for those who are likely to need them for the longest time, older patients may have no choice but to accept a lesser grade of kidney. The topic is likely to be high on the agenda of the American Transplant Congress in San Francisco in May.

To those who see their options slipping, any risks posed by an age-matched kidney must be measured against their quality of life on the waiting list.

Earl Olsen, 60, a former airline service employee from San Jose, had been on the kidney waiting list since October 2004. On Dec. 13, he agreed to receive a transplant from a 60-year-old man who had died of a stroke. "It did not take much convincing,'' he said.

Like many kidney patients, Olsen found life on dialysis hard. He had allergic reactions to chemicals used in the process. His appetite plummeted. "Take what a 6-year-old might eat at the table. Cut it in half. That was a normal meal for me," he said from his California Pacific Medical Center bed.

His new kidney was trucked to San Francisco on ice. Just as the anesthesia was taking him under in the operating room, Olsen overheard some good news. "I heard my doctor say, 'This is going to be an easy one,' '' he said.

Transplant surgeon Dr. Harish Mahanty later told him that the new kidney changed color and started producing urine as soon as he released the clamp that let Olsen's blood flow into it -- both good signs.

"I'm told it would have been a top-of-the-line kidney for anyone, except that the donor was 60 years old and died of a stroke,'' Olsen said. "My nephrologist said that, if there is no rejection, the kidney is going to outlive me.''

Dr. Stephan Busque, a transplant surgeon at Stanford University Medical Center, said that if the current allocation system remains the same, the waiting list among older patients in particular will continue to grow. No matter how kidneys are allocated in the future, there is likely to be a rising number of older patients who cannot wait for the best kidney possible.

A system that matches kidney grade to anticipated survival time of the patient -- a measure of "net survival benefit" -- makes sense to him. "It is a consideration that could be modified by other factors, such as how long they have been on the waiting list,'' he said.

On Nov. 15, Busque transplanted an ECD kidney into Karen Kopriva, a 52-year-old Lafayette woman who nearly died of septic shock while on the waiting list in 2003. Kopriva had already had a heart and lung transplant in 1998, and the anti-rejection drugs she took at the time probably damaged her kidneys.

For her, it made perfect sense to go for an ECD transplant. "I'm just not likely to have average longevity," she said. "But to have a good kidney, instead of a great kidney -- that's the way to go."

Kopriva relied on Busque to determine whether the substandard kidney was good enough for her. In fact, she had been scrubbed and rolled to the operating room for an ECD transplant earlier this year when Busque called off the surgery. He rejected the kidney she was about to receive. "I didn't argue with him,'' she said.

Any system of grading and allocating kidneys will rely enormously on trust between physician and patient.

Harvard transplant surgeon Dr. Francis Delmonico, who is the immediate past president of the United Network of Organ Sharing, said he cannot expect many of his patients to understand the complex calculus involved in weighing the risks and benefits of lower-grade kidneys. That will always remain a primary role for the team of physicians. He said it boils down to this: "The patient always asks, 'Is this a good kidney for me, or not? What do you think, Doctor?' "
A lesser kidney

Expanded Criteria Donor kidneys come from deceased donors who are over the age of 60 or who have other health factors that make the organ less desirable for transplant than a standard kidney.

Kidneys from donors ages 50 to 59 who have a history of high blood pressure or die of stroke are also labeled ECD, because hypertension or other conditions that lead to stroke may impair the longevity of kidneys. Doctors also measure the level of creatinine -- a waste product normally filtered from blood by kidneys -- in a potential donor.

Kidneys from donors ages 50 to 59 with levels of creatinine that are higher than acceptable (1.5 mg/dl) are also considered ECD. Currently, 15 percent of all donated kidneys are ECD.

E-mail Sabin Russell at srussell@sfchronicle.com.

A hazardous wait

The waiting list for kidney transplants
in the United States has nearly doubled since 1994, and over the same period,
the number of patients who die awaiting a kidney transplant has risen from
1,625 to 4,030.

Patients* waiting for donor organs
'95 41,719
'04 77,148

Death of patients* waiting for donor organs
'95 1,625
'04 4,030

*Patients alive on the waiting list anytime during the year are counted.

A gamble to survive

Some may be able to shorten their wait on the list by accepting kidneys
from donors who are older than 60 or who may have other health problems. These
ECD kidneys may save patients who would otherwise die on the waiting list, but
recipients are more likely to die after the transplant than those who receive
standard kidneys.

Patient survival rates
Standard kidney ECD kidney
transplant transplant**
3 months (2002-2003) 98.2% 96.1%
1 year (2002-2003) 96.0% 91.1%
3 years (2002-2003) 90.5% 81.3%
5 years (1998-2003) 84.5% 69.6%

** Expanded Criteria Donor (ECD) program began in 2002. This analysis
compared
ECD-equivalent kidneys transplanted prior to that program

Source: United Network for Organ Sharing
The Chronicle

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