CHICAGO — Here’s the scenario. Your kidneys are toast. You are going to die, probably within a few weeks. The diagnosis is end stage renal disease.
You could do nothing, and maybe you’re OK with that, or you could undergo dialysis. But what if you could get a kidney transplant?
Kidneys are the water treatment plant of the body. Stuffed full of thousands of nephrons, kidneys filter excess water, waste and electrolytes out of the body as urine. When kidneys can no longer perform their job, waste must be cleaned out of the body through dialysis.
In the United States, nearly 100,000 people are on the waiting list for a kidney transplant, said Sanjay Mehrotra with Northwestern University. Another 400,000 are being kept alive through treatment with dialysis. For individuals with kidney failure, a transplant is the best form of therapy, but most people have no choice but to move forward with dialysis.
At the 2014 AAAS Conference, experts came together to discuss the national shortage of transplant organs and the need for new policies that would address, in particular, kidney allocation and distribution.
“We are so good at doing transplants that everyone who has end stage renal disease wants one, but we don’t have enough kidneys,” said John Friedewald, associate professor in Medicine-Nephrology and Surgery-Organ Transplant at Northwestern University in Illinois. “Demand is far beyond the supply for organs.”
This is due in part to the inefficiency of current policies surrounding kidney transplants.
Additionally, to ensure a match between kidneys and patients, a number of tests must be run and location plays a critical role. Transplant waiting times can be as short as nine months or as long as five years, but these times often vary by as much as a year across state lines, Mehrotra said.
In this way, a lot of organs are wasted, Friedewald said. “We procure a lot of organs that are never transplanted.” They never make it to the right person.
One of the first processes a patient undergoes when being added to the transplant list is an assessment to determine their panel reactive antibodies percentage, or PRA percent. The process involves taking a patients serum (a light yellow liquid collected from a blood sample after it is spun in a centrifuge) and testing it for sensitization against 100 donor blood samples. A 20% PRA means that the antibodies in the patient’s blood reject 20 of the 100 donors. The lower the PRA, the better. When assessing who is first on the list for a kidney, patients with high PRAs receive additional consideration, because they are the least likely to find a suitable match.
Crossmatching is one of the final steps of testing before moving to a transplant. It involves mixing donor blood and patient serum to see if there is any clumping, or agglutination. If the blood clumps together instead of mixing, this means the kidney would be rejected and isn’t suitable for a transplant in this patient.
Another component of matching individuals is to make sure that the kidney came from someone of similar age. By matching the age of the kidney and the age of the patient, surgeons can ensure that the longevity of the kidney matches with the candidate. This means, instead of placing a kidney from a 24-year-old into someone who is 79, they should aim to transplant a 65-year-old kidney with a 73-year-old candidate. By doing so, surgeons could reduce the need for repeat transplants.
In response to the increasing need, the all-time high mortality rate for patients on wait lists and the disparity of wait list times across regions of the United States, a new kidney allocation policy is being implemented in 2014 is in the process of being implemented by the Organ Procurement and Transplantation Network, or OPTN. The new policy would acknowledge medical urgency.
Under old policies, patients with kidney failure would spend decades living on dialysis and still wind up on the bottom of the transplant list. Waiting time began at registration, regardless of the number of years on dialysis.
With good implementation of the new protocols involving organ transplants, OPTN estimates that they would add a total of 8,000 years of life across all patients receiving kidneys annually.