Kidney Transplant: Improving Outcomes
Christopher Johnson, MDMedical College of Wisconsin Transplant Surgeon
and Director, Transplant Center
Named one of the Best Doctors in America 2006® by Best Doctors, Inc.
Twenty million Americans suffer from kidney disease, a progressive condition that eventually leads to kidney failure. When the kidneys fail, patients have two options: dialysis or kidney transplantation. While dialysis maintains life, kidney transplantation provides more complete restoration of kidney function and is associated with a higher quality of life than chronic dialysis.
Q. What critical functions do the kidneys provide?The primary function of the kidneys is to excrete waste products that build up in the body as the result of normal metabolism. The kidneys also make erythropoietin, a hormone which is critical for red blood cell production and plays a vital role in calcium and bone metabolism
Q. Why or when would a person need a kidney transplant?There are a number of chronic diseases that can affect the kidneys. The most common ones are diabetes and hypertension. There are many other kinds of more specific kidney diseases. The chronic diseases, such as diabetes and hypertension, tend to result in a slow loss of renal function. When a person gets to the point where their kidney function is only about 15 percent to 20 percent of normal, they start to have symptoms of kidney failure, which can consist of high blood pressure, fluid buildup, nausea, fatigue and just a general feeling of malaise. As that percent function gets lower and lower, patients become progressively more symptomatic. At some point, an intervention needs to occur; most patients end up going on dialysis as the next step. Their options at that point are to continue chronic dialysis indefinitely or to pursue an alternative therapy. Kidney transplantation is that alternative therapy.
It is possible for someone to get a kidney transplant without going on dialysis first. And that is increasingly being recommended. But I would say that dialysis probably ends up being the most common scenario initially, because unfortunately, kidney disease tends to be recognized late, and often patients present so ill that they have to be placed on dialysis urgently; there is no time to do a kidney transplant. In the situation where a patient is followed closely by a primary care physician and renal disease is diagnosed early, it’s usually possible to follow their kidney function along, and at the point where the kidney function is severely impaired, it is possible to refer for transplant outright and thereby avoid dialysis.
One thing that’s being recognized now in kidney transplantation is that the sooner you do it, the better the outcome. This is now recognized because there are so many thousands of patients that have accrued on waiting lists for kidney transplant that patients are now waiting longer than ever. As a result of that, one can see that the outcomes go down as a person languishes on dialysis for year after year. So someone who’s been on dialysis for five years, for example, does not get the same outcome with a transplant as somebody who gets it before they ever go on dialysis.
Dialysis is a life-saving therapy, but you’re kind of living on borrowed time, if you will. It’s not curative treatment. I describe it to patients as a very simplistic filtering process. When one goes on dialysis, they have three treatments per week and each treatment is approximately three hours. So your blood is filtered for nine hours out of the week. That’s not very long, because there are seven days in a week and 24 hours in a day. The percentage of time you’re actually getting that filtration is very, very minuscule. The rest of the week, your body remains in renal failure, and it’s continuing to accumulate toxic waste products. That leads to damage — heart, blood vessels, nerves, bone — many, many kinds of secondary complications of long-term dialysis. Some of them are irreversible once they set in. So the sooner you undergo a curative therapy such as a transplant, the better the outcome can be.
Q. Is transplantation the only option for kidney disease?You really just have two options, dialysis or transplant. Transplantation is usually, and I emphasize usually, the best option, but there are situations where it’s not the best option. If someone has very advanced medical problems – severe coronary disease, morbid obesity, multiple strokes, decreased functional status — they don’t do very well with a transplant. It’s not a realistic option. But for most relatively healthy patients, it is the best option. Age itself is not exclusionary, although we generally don’t recommend transplants for patients over age 70.
You also have to meet certain criteria to be able to get a kidney transplant. Number one, you’ve got to be compliant with medical therapy. In order for a transplant to work out successfully, there are two big elements to the process. One is the surgical procedure itself; you need to have successful implantation of the organ. But the second phase is equally important, and that’s long-term medical management of the patient through the transplant clinic: regular physician visits, laboratory tests on a regular basis to assess transplant function, monitoring medications, those sorts of things. And that’s a fairly intensive follow-up. Some patients are not capable of following through; they don’t have the system support, or are not sufficiently motivated. And for those, transplant is not the best option. Then there are other situations — patients that have cancer that is not controlled or active infections – that are medical contraindications to transplant.
Q: What are the options for kidney transplantation?Patients can receive a transplant from a living donor or from a deceased donor.
Living donors are being utilized increasingly often now. In fact, in this country the number of living donors now roughly equals the number of deceased donors. However, deceased donors have two kidneys available, whereas a living donor can only donate one kidney, so there still are roughly twice as many deceased donor transplants as there are living donor transplants.
The composition of the living donor pool has changed dramatically over the past ten years. It used to be that living donors were primarily close family members — siblings, parents — but now, unrelated donations, such as spouse, best friend and extended family members, are increasingly common. They form up to a quarter of the number of living donors nowadays, whereas ten years ago, they were less than 5 percent.
That’s where a lot of the increase in living donation is coming from. The effectiveness of current anti-rejection medications means that there’s less of a need to rely on matching. In fact, we hardly rely on matching at all now. It’s nice to have and we view it as kind of an extra bonus, but it’s not required. All we need really is to have what we call blood-type compatibility. As long as there’s blood group compatibility, the anti-rejection medications that we have are so good, we can pretty much work with any match. That’s a big improvement in the last ten years, and that allows us to use pretty much any living donor.
The second thing that’s driving the increase in living donation is the need. Right now, there are 68,000 patients on the kidney transplant waiting list in the United States. Last year, only 16,000 kidney transplants were done in this country. So unfortunately, every year there are more people added to the list than transplants done that year. I think the increasing disparity between the number of patients in need and number of organs available is driving more people to donate.
The long term outcomes for living donor kidney transplants are also generally better than those for deceased donor transplants. That’s for a couple of reasons. Because a living donor, by definition, is not allowed to donate unless they have two healthy kidneys, a living donor kidney is always an excellent organ. The way the donation occurs also facilitates a good outcome. The surgery is scheduled electively. Both patients are operated on essentially at the same time in adjacent operating rooms, and the kidney is removed from the donor and walked right over into the recipient room, where it’s implanted immediately, with essentially no storage time or damage. That leads to immediate function of the kidney. It’s very rare for a recipient of a living donor kidney to need dialysis in the post-transplant period, whereas in the case of a deceased donor, up to 25 percent of patients need dialysis for a short period of time while the kidney kicks in.
So the living donor kidney typically achieves better baseline kidney function which is an important predictor of long term outcome. In contrast, the deceased donor pool consists of all the available potential deceased donors. One of the most common diagnoses now for a deceased donor is hypertension. Diabetes and other medical diseases are also common.
The decreased donor population in general has many medical problems that can affect the kidney function. So you’re not always able to get a perfect kidney from a deceased donor. So in summary, a living donor kidney tends to be of higher quality and longer lasting.
You can also schedule a living donor transplant such that the recipient can be more completely evaluated. With a deceased donor transplant, it works a little differently. A kidney becomes available, you run through the list and identify the person who is at the top. They rush into the hospital, get a quick, updated medical evaluation and then get rushed to surgery. You can see how that doesn’t lend itself to addressing things quite as thoroughly in terms of identifying potential medical problems or issues. Even so, the whole process takes an average of 15 to 20 hours so the kidney is on ice for an average of 15 to 18 hours, and there’s some potential for tissue damage. That’s why about 25 percent of recipients of deceased donor kidneys require one or more dialysis treatments while the kidney kicks in.
Now having said all that, the results for deceased donor transplants are pretty darn good. The one-year success rate for a deceased donor kidney transplant in the United States is about 90 percent. With a living donor, it’s about 95 percent. But because of this issue of quality of function, when you start looking at longer term outcomes, the average living donor kidney lasts close to 20 years, whereas the average deceased donor is closer to ten. It’s just a slight difference at one year, but it keeps building over time. Most people get only once chance for a transplant, so you want it to be their best.
Q: How long has the Kidney Transplant Program been around at Froedtert & the Medical College of Wisconsin?The first kidney transplant was performed here in 1967. It was one of the first kidney transplant programs in the United States.
Q: How important is prevention and what can I do?Just follow the basic tenets of good health — exercise, control your weight, no smoking, those basic things. Probably the biggest risk factors for renal disease are number one, high blood pressure, and number two, diabetes. Unfortunately, diabetes and hypertension have a strong genetic component, but exercise and diet still have a role. Primary care is also important. The other thing that’s important is that if you develop early signs of kidney disease, you probably should see a kidney specialist.
Source: Every Day, Interview with Christopher Johnson, MD
Date: Jan - April 2007