The traditional way to treat people with advanced kidney disease has been to use dialysis to remove waste from the blood while patients wait several years for kidneys from deceased organ donors. At Mayo Clinic, transplant surgeon Dr. Mikel Prieto and colleagues advocate for a different approach called preemptive transplantation: Kidneys from living donors are allowing many people with advanced kidney disease to receive transplants before their kidneys deteriorate so much that they need dialysis.
Chronic kidney disease afflicts roughly 1 in 10 people worldwide and causes millions of deaths each year, according to the International Society of Nephrology. Kidneys filter waste and excess fluids from the blood that the body then expels in urine. Kidneys also help control blood pressure. In chronic kidney disease, kidneys gradually lose their effectiveness. Dangerous levels of fluid, electrolytes and waste can build up. Dialysis has traditionally been the next step.
Dialysis removes waste and extra fluids from the blood, restores electrolyte levels (helping muscles, the heart and the brain work well) and aids blood pressure control. Depending on the type, dialysis can take place at home or at a dialysis center. If the patient is a candidate for a kidney transplant, dialysis can be a bridge to transplant. Dialysis takes hours multiple times per week and often requires significant lifestyle changes and dietary restrictions. Dialysis may occur for years if a patient is waiting for a kidney from a deceased donor.
Dialysis extends life but unfortunately it often doesn't yield great quality of life, explains Dr. Prieto, who performs pediatric and adult kidney transplants and is surgical director of the pediatric kidney transplant program at Mayo Clinic in Minnesota.
"People on dialysis may feel kind of lousy for the most part. Although some manage to stay working and engaged in their other activities, a small percentage of patients on dialysis have a full, normal life," Dr. Prieto says. "Second, your body deteriorates because even though dialysis keeps you alive, it does not do a fantastic job at cleaning out all the waste. So, if someone is on dialysis for seven years and you look at their arteries, they may be a 40-year-old, but their arteries and blood vessels look like a 70- or 80-year-old. You want to minimize the amount of dialysis if you can."
That is where living kidney donors come in. A living kidney donor is someone who donates a healthy kidney on behalf of a family member, friend or even a stranger. If the living donor's kidney isn't a direct match for an intended recipient, it can become part of a paired donor chain. The incompatible donor's kidney goes to someone who is a match, and the donor's intended recipient receives a kidney from a different and compatible donor. Donor chains can include several donor-recipient pairs.
"Typically, unless you are really hard to match, we'll find a matching kidney for you within weeks or two to three months," Dr. Prieto says. "When you come for a transplant evaluation, we will ask whether you have or could have a living donor. If you don't, we will explain how to find one."
There are other potential advantages to donor chains: The living donor and the kidney recipient, frequently spouses or close relatives, can be each other's caregivers after surgery. Participation in separate donor-transplant chains can ensure that their surgeries do not occur at the same time.
Mayo Clinic campuses in Arizona, Florida and Minnesota have extensive experience with living donor kidney transplants and living donor chains. At Mayo Clinic in Minnesota, roughly half of the patients who receive kidney transplants get them from living donors before their kidneys decline so much that they need dialysis, Dr. Prieto says.
"Most people know for years in advance that they are going to need dialysis at some point, or a transplant," he explains. "It's much better to plan for a transplant now because waiting times for a deceased donor can be years. During that waiting time, your kidney function keeps deteriorating."
Patients typically become candidates for a kidney transplant when their kidney function drops below 20%. Dialysis usually starts when function reaches around 10%. If you start thinking about transplantation at this time, it is often too late, and you will be on dialysis awhile, Dr. Prieto says.
"So that's the sweet spot: transplant between 20% and 10% of kidney function. That's what we call preemptive transplantation," Dr. Prieto says. "That's what we try to do here at Mayo. If we time things right, we can do the transplant and avoid dialysis altogether."
Dr. Prieto and Mayo Clinic are early adopters of living kidney donation, paired donation and donor chains. In the U.S., the National Kidney Registry facilitates living kidney donation and donor chains. Mayo Clinic is a member institution and Dr. Prieto serves on the registry's medical advisory board.
Many of the patients Dr. Prieto treats have autosomal dominant polycystic kidney disease, an inherited condition in which clusters of cysts grow and substantially enlarge kidneys, potentially causing kidney failure. Symptoms often appear in middle age. In the conventional approach, such patients would have their kidneys removed, go on dialysis, and then months or years later have a kidney transplant.
Dr. Prieto has perfected a technique that spares people with polycystic kidney disease multiple visits to the operating room. He removes the enlarged kidneys laparoscopically, a minimally invasive approach that prevents a large incision. Then, in the same operation, using a kidney usually from a living donor, he gives the patient a new kidney.
"In many cases of polycystic kidney disease, the kidneys are so big that it's very uncomfortable," Dr. Prieto says. "People cannot tie their shoes. They cannot bend over. They eat and feel full very quickly. Even breathing sometimes can be difficult. Also, their kidneys can bleed chronically, so patients are hospitalized with severe pain, bleeding or infection."
He and his colleagues are now embarking on another new frontier: They seek to give patients kidneys that are such a perfect match that their bodies are much less likely to reject them, diminishing the need to take a high dose of immune system-suppressing drugs.
"We want to give patients kidneys they will never reject," Dr. Prieto says.
