Wearable Artificial Kidney - History & Motivation

History & Motivation

Chronic kidney disease (CKD) affects 26 million people in the United States, and around 550,000 of these patients have end-stage renal disease requiring dialysis or transplantation. The mortality rate for patients with end-stage renal disease is around 22% per year, and at the moment, dialysis is the only therapeutic option for these people. Dialysis therapy is usually given three times a week for four hours at a time, and it involves many risks such as bleeding, clotting, and infection. For patients and society in general, the emotional and financial costs of dialysis therapy are very high. The quality of life for patients on dialysis is often very low, and the yearly cost of treating end-stage renal disease exceeds $30 billion in the US alone.

The ideal wearable kidney would mimic the function of the kidneys by providing:

1. continued dialysis (to avoid the sudden electrolyte disturbances associated with timed dialysis), and
2. be effectively autonomous so that little to no patient intervention is necessary.

Methods of implementation range the same spectrum as traditional dialysis. Experiments have been carried out since the seventies, and included miniature hemofilters utilizing REDY cartridges or by drinking dialysate. The development of continuous ambulatory peritoneal dialysis was successful and significant achievement, but it requires significant patient intervention.

However this technique has failed to gain acceptance with the vast majority of the patients. In many undeveloped countries it is the preferred or at times the only dialysis modality available due to its lower cost. Some of the disadvantages of this technique are that it loads patients with large amounts of carbohydrates which may not necessarily be beneficial, it may be less effective in achieving appropriate fluid removal unless large amounts of sugar are infused into the patient and the filtration capabilities of this techniques are lost over time.

The main reason however, to pursue a wearable artificial kidney is that it would work continuously, 24 hours a day, 7 days a week, filtering the blood in a continuous mode very much like our natural kidneys do. Furthermore, hundreds of scientific papers, including randomized controlled trials, extol the advantages of more frequent dialysis for much longer periods of times, preferably daily.

On the other hand there are numerous logistic and economic barriers that render daily dialysis impractical and unaffordable. Also, dialysis patients do not particularly enjoy the perspective of spending many hours of their life tied to a machine that impedes their ability to work or perform other activities.

In contrast, a wearable artificial kidney small and light that does not impede walking, working of performing any activity of daily life will greatly contribute to improve patient’s quality of life. In addition, the continuous removal of excess water, salt and toxins would allow patients to be free to enjoy any diet and fluid intake of their choice, without fear of poisoning themselves to death or landing in the hospital. Also it would greatly reduce the burden of having to swallow large amounts of pills. Also, significant cost reductions would be expected from implementing such technical advances. Thus, the hopes are high, that the Wearable Artificial Kidney (WAK) will greatly improve the quality of life dialysis patients, reduce their mortality and save a great deal of money.