Changing paradigms of renal replacement therapy in chronic kidney disease patients: ultrapure dialysis fluid and high-efficiency hemodiafiltration for all?

Global prevalent use, trends and practices in haemodiafiltration

Online haemodiafiltration (HDF) represents today the most advanced and innovative form of renal replacement therapy (RRT). Recent controlled trials tend to prove its superiority over conventional haemodialysis on hard clinical end points provided that the right convective dose was delivered. In this article we report on present prevalent use and epidemiologic trends of HDF worldwide as well as on practice patterns in HDF prescription. In addition we analyze factors that may affect HDF clinical acceptance and more widely its implementation. National and international renal registries provide valuable demographic and epidemiologic information on end stage kidney disease patients on RRT. However, the updating and maintenance of such information system is particularly challenging at a country level and even more so on an international basis. Lag time, incompleteness and/or imprecision of data collection may further hamper precision and validity of data reporting. Fresenius Medical Care (FMC), as a large dialysis care provider operating worldwide, maintains an annually updated database addressing international end stage kidney disease data. Over the last decade, FMC has produced series of precise and reliable reports analyzing RRT trends and practices worldwide. The present overview and analysis is based on our consolidated data from market survey as well as national database registries and databases of recent studies. Online HDF acceptance is growing fast in the two leading regions having approved the method, i.e. Europe and Asia Pacific, with a patient average growth rate of 12 to 24%, being far above the total patient HD growth rate of 6.6%. Today online HDF represents a new paradigm shift in RRT with promising clinical results. Further initiatives (e.g., Kidney Health Initiative, NICE) might provide further push for promoting HDF as a new standard of care in end stage kidney disease patients on a global scale.

Hemodialysis and water quality

Over 383,900 individuals in the U.S. undergo maintenance hemodialysis that exposes them to water, primarily in the form of dialysate. The quality of water and associated dialysis solutions have been implicated in adverse patient outcomes and is therefore critical. The Association for the Advancement of Medical Instrumentation has published both standards and recommended practices that address both water and the dialyzing solutions. Some of these recommendations have been adopted into Federal Regulations by the Centers for Medicare and Medicaid Services as part of the Conditions for Coverage, which includes limits on specific contaminants within water used for dialysis, dialysate, and substitution fluids. Chemical, bacterial, and endotoxin contaminants are health threats to dialysis patients, as shown by the continued episodic nature of outbreaks since the 1960s causing at least 592 cases and 16 deaths in the U.S. The importance of the dialysis water distribution system, current standards and recommendations, acceptable monitoring methods, a review of chemical, bacterial, and endotoxin outbreaks, and infection control programs are discussed.

Emerging clinical evidence on online hemodiafiltration: does volume of ultrafiltration matter?

Online hemodiafiltration (OL-HDF), first described in 1985, is today a widely prescribed treatment modality for end-stage chronic kidney disease (CKD) patients. Other than in the United States, prescription of the treatment modality is widespread with a steady increase since its inception. Indeed, in Western Europe, more CKD patients receive OL-HDF than peritoneal dialysis, hitherto the second most prescribed therapy after conventional hemodialysis. The rise and success of OL-HDF can be attributed to diverse clinical advantages that have been documented over the last two decades. Numerous publications attest to the beneficial effects of OL-HDF in terms of removal of a broad spectrum of uremic toxin, anemia control, phosphate reduction, increased hemodynamic stability and blood pressure control and less dialysis-related amyloidosis, to mention just a few. Significantly, the improvement in these conditions is considered to contribute to improved patient outcomes. Despite the extended worldwide clinical experience, elaborate scientific validation of the principles of the therapy and technical innovations that facilitate its prescription, a point of contention is whether OL-HDF leads to a reduction of mortality rates. A number of observational and retrospective analyses have indicated a survival benefit, while prospective investigations involving small numbers of patients but nevertheless specifically addressing survival have further supplied evidence of improved survival with OL-HDF. The quest for large-scale, multicenter prospective randomized controlled trials examining patient survival led to the CONTRAST and the Turkish OL-HDF trials. Both trials have been concluded and published recently. In this chapter, we document and assess the key investigations that have examined the impact of OL-HDF on patient outcome and survival. Based on the findings of previous analyses and of the two recently concluded trials, it appears that the volume of convection appears to be decisive towards the survival benefit accredited to OL-HDF. We consider the implications of this new evidence.

The rise of hemodialysis machines: new technologies in minimizing cardiovascular complications

Hemodialysis (HD) is a life-saving treatment for more than 1,700,000 patients with chronic kidney disease (CKD) stage V. Every year the HD population becomes increasingly older (average age: 75 years) and more ill due to the associated comorbidities such as cardiovascular disease (heart failure, coronary heart disease and peripheral vascular disease), diabetes, hypertension and peripheral vascular disease. Most of the complications associated with HD involve the cardiovascular system. HD machines have been greatly improved over the last 30 years. We have moved from HD machines simply allowing extracorporeal circulation to high technological medical devices capable of very precisely controlling ultrafiltration, dialysis dose, the patient's core temperature, circulating plasma volume, plasma sodium and producing unlimited volumes of ultrapure dialysate. In this article, we will focus on some of the fundamental achievements in HD machine technology, with particular reference to monitoring tools and bioengineering approaches for biosignal analysis. We propose that along these lines of further development, HD machines in the future will enable a better online identification of patients at higher cardiovascular risk, thus allowing clinicians to select more appropriate treatment modalities and parameters.