Wearable Dialysis Unit Effective in Tryout

Peggy Peck
LONDON, Dec. 13 -- An investigational wearable hemodialysis device demonstrated promising safety and efficacy in a pilot study of eight patients with end-stage renal disease, researchers here reported.But three of the eight patients who tried out dialysis on the hoof for four to eight hours had serious adverse effects involving coagulation and vascular access, said Andrew Davenport, M.D., of University College Hospital Medical School, and colleagues.
Action Points
Explain to interested patients that the device described in this report is investigational and it is not available for clinical use.
Patients using the device achieved a mean flood flow of 58.6 mL/min, with a dialysate flow of 47.1 mL/min, the investigators reported in the Dec. 15 issue of The Lancet.
The mean plasma clearance rate was 22.7 mL/min and mean plasma creatinine clearance rate was 20.7 mL/min.
The device used in the trial was developed by Xcorporeal Inc., of Los Angeles.
Patients were connected to the artificial kidney by their usual vascular access for dialysis. Heparin dose was adjusted to maintain an activated partial thromboplastin ratio of 1.5 to 2.0.
Patients were encouraged to eat and drink normally during the trial and five patients who attempted to sleep during the study were able to do so.
"All patients were pleased with treatment, and had no complaints," the investigators wrote. "They stated unanimously that they would recommend this device to other patients."
Because the device is designed to be used on a daily basis for extended periods "blood flow rates were much lower than those achieved in conventional hemodialysis, as were the clearance rates for urea and creatinine."
Two patients developed clotting problems at vascular access sites, but in both cases heparin dosing had been reduced. "Thus for the wearable artificial kidney to be successful, patients require anticoagulation," they wrote.
A third patient had a temporary disconnection caused by a dislodged fistula needle, said Dr. Davenport.
All patients in the trial had been receiving hemodialysis for an average of 17.9 years and all were receiving regular hemodialysis three times a week at the time they volunteered for the study. Five of the patients were men and the average age of patients was 52.
Four of the patients had kidney failure as the result of glomerulonephritis, three had polycystic kidney disease as the cause, and one had obstructive uropathy.
The first three patients wore the device for three hours, the fourth patient wore it for seven hours and the remaining four were treated for eight hours with the wearable dialysis unit.
Compared with baseline, mean bodyweight was significantly lower after treatment (P0.01) and the ratio of extracellular to total body fluid was also significantly lower (P=0.0019).
In a commentary, Garabed Eknoyan, M.D., of Baylor College of Medicine in Houston, wrote that the wearable artificial kidney was "a small first step in the long road to wearable blood-cleansing devices. Lessons learned from further study should pave the way for realizing the future promise of dialysis with artificial kidneys."
Dr. Davenport agreed that more studies are needed and he concluded that in order to be truly a breakthrough the wearable dialysis unit will need to be "worn continuously, or for extended periods every day to increase flows and therefore clearance rates."
Dr. Davenport said he had no conflicts to declare but three of his co-authors are employees of Xcorporeal, which developed the device and funded the study. Dr. Eknoyan had no financial conflicts.
Primary source: The LancetSource reference:Davenport A, et al "A wearable hemodialysis device for patients with end-stage renal failure: a pilot study" Lancet 2007; 370: 2005-10.Additional source: The LancetSource reference:Eknoyan G, "Artificial kidneys: progress and promise" Lancet 2007; 370: 1977-78.