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UNRESOLVED ISSUES IN DIALYSIS: Introduction

Regardless of the chosen dialysis modality, the morbidity and mortality afflicting patients with chronic kidney failure remain distressingly high. The results of two landmark randomized controlled trials, the Hemodialysis (HEMO) study (1) and the Adequacy of Peritoneal Dialysis in Mexico (ADEMEX) study (2), provide compelling evidence that the conventional approaches to hemodialysis and peritoneal dialysis dosing are limited in their ability to improve patient outcomes. The disappointing results of these costly trials, which focused primarily on changes in urea kinetic modeling-related parameters, call for a redefinition of dialysis adequacy in much broader terms than heretofore applied. This issue of Seminars in Dialysis is dedicated to “unresolved issues in dialysis” and revisits the topic of hemodialysis and peritoneal dialysis dose in light of the disappointing results of the aforementioned clinical trials. Evidence is provided in support of the pathophysiologic importance of the clinically silent cardiac and vascular deposition of amyloidogenic proteins, such as β 2 microglobulin. To improve clinical outcomes, it is argued that we need to adopt alternative extracorporeal strategies aimed at enhancing the removal of such middle molecular weight toxins. Facts and myths about the putative benefits of ultrapure dialysate are discussed. An authoritative review on dialyzer “best practices” in the 21st century is presented, a topic of ongoing controversy, debating dialyzer reuse versus single use. The merits and pitfalls of inflammatory biomarkers and cardiovascular risk stratification in the dialysis population are reviewed, as well as the controversial effect of excess adiposity on survival. A comprehensive, yet practical approach to the management of four common and vexing problems is provided, including intradialytic hypertension, hyporesponsiveness to erythropoiesis-stimulating agents, sleep disturbances, and the long-term dialysis tunneled central venous catheter. Finally, as nephrologists and intensivists await the conclusion of the Acute Renal Failure Trial Network (ATN) (3), the largest ongoing randomized controlled trial of intensive versus conventional renal support in acute renal failure, a state-of-the-art approach to the dialysis modality and dosing strategy in acute renal failure is presented. It is my hope that the presentations on controversial topics offered in this issue will provide an additional stimulus to nephrologists to continue challenging dialysis care in the new millennium. Such a challenge should place special emphasis on a new paradigm of dialysis adequacy that is tailored to novel dialysis regimens and frequency strategies. Equally important, other areas of adequacy, including health-related quality of life, sleep quality, extracellular fluid volume balance/blood pressure regulation, anemia control, and optimization of vascular access care and nutritional status, should attract our focused attention, thereby culminating in a more holistic approach to the care of dialysis patients. I wish to thank the contributors to this issue of Seminars in Dialysis for lending their time, effort, and expertise. I also wish to express my appreciation to Dr. Richard Sherman for giving me the opportunity to serve as guest editor of this issue. Finally, I would like to thank my family for their continued encouragement and support.