By Sandy Marvinney 


Breaking News

We have a late-breaking update on the story below, which covers the clinical trial of the wearable artificial kidney (WAK) at UW Medicine. Results on the trial’s findings were presented at the annual meeting of the American Society of Nephrology in early November. Now that the results are public, Jonathan Himmelfarb, M.D., was pleased to release the following statement.

“Treatment with the WAK was safe, well-tolerated and effectively cleared patients’ uremic solute while maintaining electrolyte and fluid balance,” says Himmelfarb. “These results serve as proof that, after the device is redesigned to overcome some technical problems, a wearable artificial kidney can be developed as a viable dialysis technology.”

Good news for people with kidney disease. Read more about the device and the trial below. And watch the video of Chuck Lee, one of the patients who tested the device.

Wearing your heart on your sleeve: an old poetic idiom and a physical impossibility. Wearing your kidney on your belt? A life-saving idea that is now being tested.

At left: Jonathan Himmelfarb, M.D. (left), unpacks the WAK for Victor Gura, M.D. (center), and Larry Kessler, Sc.D., UW professor of health services. At right: John Kundzins of Northwest Kidney Centers models the device.
Photos: Stephen Brashear

A wearable artificial kidney (WAK) is a decades-old concept, impractical to develop until the advent of novel technologies and new biomaterials. This spring, UW Medicine and its collaborators concluded the first U.S. trials of a WAK prototype. The goal is to develop more effective dialysis therapies for thousands of people with kidney failure.

Fighting an epidemic

Kidney disease is an irreversible condition and the eighth leading cause of death in the U.S.

“Chronic kidney disease is a huge public health problem,” says Jonathan Himmelfarb, M.D., UW professor of medicine in the Division of Nephrology, director of the Kidney Research Institute and holder of the Joseph W. Eschbach, M.D. Endowed Chair in Kidney Research. “About 20 million people in the U.S. have chronic kidney disease.”

And the problem, unfortunately, is not going away. According to Himmelfarb, new cases are increasing every year, a byproduct of the aging of the population and the rising prevalence of diabetes and hypertension, which damage the kidneys.

“Chronic kidney disease is a huge public health problem.” — Jonathan Himmelfarb, M.D.

Then there are the costs. “It’s one of the most expensive chronic diseases — it costs more than $32 billion annually to treat the half-million end-stage patients in the U.S.,” says Himmelfarb. Federal and state budgets carry most of the financial burden.

Patients’ survival depends on long-term dialysis or transplant, but neither solution is perfect. With dialysis, patients in their twenties have just a 20-year life expectancy. Even a transplant is no guarantee; they may function only 10 years or so, requiring another transplant or a return to dialysis.

“We need breakthrough treatment technologies,” says Himmelfarb. Technologies like the WAK.

A breakthrough technology

Worn on the belt, the WAK is a miniature, battery-powered dialysis machine, connected to the patient via a catheter. New technology has made the WAK possible: lighter, better batteries; more advanced plastics; the invention of a pump that manages water and blood flow differently than in other machines; the use of certain sorbents and enzymes to clean the dialysis fluid.

In a word, freedom. “The WAK allows patients to receive continuous hemodialysis, while going about their daily activities,” says Himmelfarb. And, because the machine works continuously, it should act more like a real set of kidneys: constantly cleaning the blood so that patients will start to feel a marked improvement in their health.

The WAK’s first clinical trial took place at UW Medical Center in Seattle, and the team of collaborators included Himmelfarb and Victor Gura, M.D., the device’s developer
and founder of Blood Purification Technologies, Inc. (BPT), the early-stage technology company that is producing the prototype. Larry Kessler, Ph.D., chair of the Department of Health Services at the UW School of Public Health, monitored the patient experience and the project’s regulatory aspects. In all, the trial took six months and involved seven patients.

“From the patient perspective, the wearable artificial kidney could be the most significant technology advance since the development of long-term dialysis methods in the 1960s,” says Himmelfarb.

Refining the WAK

Many clinical studies worldwide indicate that more frequent dialysis improves patient health, which makes the WAK a very promising development for patient treatment. Its developers hope that it also lowers the cost of healthcare.

Himmelfarb can’t say too much about the trial’s results; as of press time, they were being submitted for publication. But he’s decidedly positive.

“This was a pilot study,” he says. “We are very hopeful that there will be ongoing trials that will help to make this a potential reality for patients.”

The next steps will include refining the prototype and making technical improvements. The team also plans to conduct several years of clinical testing to assess potential benefits, risks and cost-effectiveness.

“The WAK could be the most significant technology advance since the development of long-term dialysis methods in the 1960s.” — Jonathan Himmelfarb, M.D.

“We will take the research one step at a time to make sure the device is performing well,” Himmelfarb emphasizes. “We don’t want to give patients false hope, but we are dedicated to providing more treatment options in the future.”

He’s also considering how ongoing research into kidney function might affect the development of the WAK and other treatments.

“It’s little paradoxical. Some people have pointed out that development of dialysis treatment preceded a good understanding of the disease,” Himmelfarb says. “We need a lot more basic research on kidney function at the molecular and cellular levels to understand the kidneys’ true complexity and to improve treatments for all types and stages of kidney disease.”


Creating Collaborations, Saving Lives

End-stage kidney disease was a death sentence — until the creation of the Scribner-Quinton shunt at UW Medicine in 1960. The invention made long-term kidney dialysis possible. Developed by two innovators, UW Medicine researcher and patient advocate Belding Scribner, M.D., and engineer and UW professor Wayne Quinton, the shunt was a U-shaped, Teflon-coated tube installed in the arm for easy hook-up to a dialysis machine. Prior to the shunt, physicians had to destroy blood vessels each time dialysis was performed, limiting the number of treatments to five or seven. And while Scribner and Quinton initially chose a Teflon™ coating because they thought it wouldn’t react to patient tissue, the material’s most important benefit became obvious later on. In an interview with the UW, Scribner reported, “It was only much later that we found out it was the nonstick properties of Teflon™ that really made the shunt work… without the nonstick surface, the shunt always clotted.” In enabling long-term dialysis, the shunt — and the refinements that followed — have extended millions of lives.

In developing the life-saving Scribner-Quinton shunt, Belding Scribner, M.D., made long-term dialysis possible. And in founding Northwest Kidney Centers, the first outpatient dialysis program in the world, he made possible another series of ground-breaking ventures.

In 2008, Northwest Kidney Centers and the University of Washington created the Kidney Research Institute (KRI), now directed by Jonathan Himmelfarb, M.D. The success of the new institute, says Himmelfarb, is made possible by Northwest Kidney Centers’ philanthropy. “We have approximately 50 active clinical studies under way at the institute, and seed monies from Northwest Kidney Centers have contributed to the majority of these studies,” he says. Himmelfarb lists a few high-potential projects: preventing acute kidney injury in children undergoing open-heart surgery. Educating patients more thoroughly to improve outcomes from the use of home dialysis machines. Performing healthy lifestyle interventions in people with moderate to severe chronic kidney disease.

Northwest Kidney Centers also has contributed to fellowship funding, allowing the UW’s Division of Nephrology and the KRI to attract junior scientists. Himmelfarb notes that the clinical trial involving children and surgery, mentioned above, is led by a fellow.

“Northwest Kidney Centers gave us the opportunity to foster a new generation of dedicated, talented early-career investigators as well as the opportunity to pursue leading-edge research for people living with kidney disease,” says Himmelfarb. “Without this collaboration,” he says, “the Kidney Research Institute simply would not exist today.”

  • Visit, and watch Himmelfarb’s presentation on another innovation: the kidney on a chip.

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