[What's new in hemodialysis]

Dialysis is a complement to or a substitute for renal transplantation. Mortality of dialysis patients remains too high - 9-22%/year - and is associated above all with old age and comorbidities but also with the quantity and quality of hemodialysis. Hemodialysis must be more personalized, with a possible increase in its frequency (daily) or in the duration of sessions (longer than 4.5 h). Chronic inflammation, present in 30% of patients, is a source of morbidity and mortality. It must be detected by ultrasensitive CRP (C-reactive protein) assays and its cause sought and treated. Metabolism of phosphate and calcium is too often inadequately controlled, despite the contribution of new very active molecules. The resultant vascular calcifications are an important cardiovascular risk factor. Progress in dialysis techniques also plays a role in improving quality of life and life span: use of highly permeable membranes, ultrapure dialysate, closed-loop biofeedback volume control, and maintenance of thermal balance.

Coupled plasma filtration adsorption

Sepsis is one of the main causes of death in critically ill patients worldwide, and in many cases it is associated with renal and/or other organ failure. However, we do not have a unique efficient therapy to reduce this extremely high mortality rate. In the last years interest around the use of extracorporeal blood purification techniques has increased. One of the emerging treatments in patients with severe sepsis and septic shock is coupled plasma filtration adsorption (CPFA), a novel extracorporeal blood purification therapy aimed at a nonselective reduction of the circulating levels and activities of both pro- and anti-inflammatory mediators. Early experimental studies and the following clinical trials have demonstrated impressive results regarding hemodynamics and respiratory parameters, even in patients without concomitant acute renal injury, paralleled by a quick tapering of vasoactive drugs. Considering the still high morbidity and mortality rates in septic shock patients, this new blood purification technique seems to have benefits when applied early in the course of sepsis, also without renal indications, suggesting that it might be performed to prevent rather than to treat acute kidney injury.

Effect of rosuvastatin on outcomes in chronic haemodialysis patients: baseline data from the AURORA study

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death in patients with end-stage renal disease (ESRD).

AIMS

AURORA (A study to evaluate the Use of Rosuvastatin in subjects On Regular haemodialysis: an Assessment of survival and cardiovascular events) is the first large-scale international trial to assess the effects of statins on cardiovascular outcomes in patients with ESRD on chronic haemodialysis. Preliminary baseline data from the randomised population are presented.

METHODS

A total of 2,775 patients from 280 centres in 25 countries were randomised into the study. Patients aged 50-80 years on regular chronic haemodialysis for at least 3 months before screening were eligible for inclusion. They were randomised 1:1 to receive either rosuvastatin 10 mg or placebo daily and assessed throughout the study.

RESULTS

The mean age at baseline was 64 years. Most patients were male (62%) and 85% were white. The median time since commencing renal replacement was 32 months. Mean total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels were 4.53 mmol/l (175 mg/dl) and 2.57 mmol/l (99 mg/dl), respectively.

CONCLUSION

Results from the AURORA trial will impact on the current guidelines and use of statins in this patient population.

Chronic kidney disease in Cuba: epidemiological studies, integral medical care, and strategies for prevention

The experience of the Republic of Cuba regarding epidemiological studies, integral medical care, and strategies for the prevention of chronic kidney disease is summarized in this report. Cuba has a National Program for Chronic Renal Disease, Dialysis, and Renal Transplantation. There is a national nephrology net, integrated by the Institute of Nephrology as the coordinator center, that has 47 nephrology services with a hemodialysis unit (24 of them with peritoneal dialysis unit), 9 transplantation centers, 33 organ procurement hospitals, and 5 histocompatibility laboratories. In 2004, the incidence rate in dialysis patients was 111 pmp, and the prevalence rate was 149 pmp, demonstrating an increasing mean of 17.0% and 10.0% per year, respectively. Renal transplantation rate was 16.6 pmp. The detection, registration, and follow-up of patients with chronic kidney disease (serum creatinine > or =1.5 mg/dL or glomerular filtration rate <60 mL/min) by family doctors was 9,761 patients, 0.87 patients per 1,000 inhabitants. In the 1980s, three population-based screening studies were performed to define the burden of chronic renal failure in different regions of Cuba. The prevalence rate was 1.1, 3.3, and 3.5 per 1,000 inhabitants, respectively. At present, another three population-based screening studies are ongoing in order to detect the chronic kidney disease in earliest stages. The continuing medical education activities have been very useful in raising the awareness of medical doctors and the basic health staff about the threats posed by and the strategies to prevent, diagnose, and treat chronic kidney disease.

End-stage renal disease and its treatment in Latin America in the twenty-first century

The Latin American Society of Nephrology and Arterial Hypertension's Dialysis and Transplant Registry was chartered in 1991. It collects information on ESRD and its treatment in 20 countries of the region. The prevalence of patients on renal replacement therapy (RRT) increased from 129 pmp in 1992 to 447 pmp in 2004; in 2004, 56% of the patients were on hemodialysis, 23% on peritoneal dialysis, and 21% had a functioning kidney graft. The highest rates of prevalence were reported in Puerto Rico (1027 pmp), Chile (686 pmp), and Uruguay (683 pmp). Hemodialysis was widely used, except in El Salvador, Mexico, Guatemala, Nicaragua, and the Dominican Republic, where peritoneal dialysis predominated. Incidence rate increased from 27.8 pmp to 147 pmp in the same period of observation; the lowest rate was reported in Guatemala (11.4 pmp) and the highest in Puerto Rico (337.4 pmp). Diabetes mellitus was the leading cause of renal failure in incident patients; the highest rates were reported in Puerto Rico (62.2%) and Mexico (60%). Forty-four percent of the incident population were older than 65 years. Access to renal replacement therapy was universal in Argentina, Brazil, Chile, Cuba, Puerto Rico, Uruguay, and Venezuela, while was restricted in other countries. Main causes of death in dialysis were cardiovascular (44%) and infectious disease (26%). The rate of renal transplantation increased from 3.7 pmp in 1987 to 14.5 in 2004; fifty-three percent of the organs came from cadavers. Overall, donation rate was 5.9 pmp. In conclusion, the prevalence and incidence rates have increased over the years, and diabetes mellitus has emerged as the leading cause of kidney disease in the region. Although the rate of kidney transplantation has increased, the number remains insufficient to match the growing demand. The implementation of renal health programs in the region is urgently needed.

The endless history of vascular access: a surgeon's perspective

Gaining access to blood circulation has been a major breakthrough of modern medical care and, despite the evolution of dialysis technology, vascular access (VA) remains the main impediment in providing quantity as well as quality of life to the end-stage renal disease (ESRD) patient. The external Scribner shunt and the internal Brescia/Cimino arteriovenous fistula (AVF) opened the way for further advancements such as graft angioaccess and other sophisticated devices. Forty years later, the radio-cephalic fistula remains the VA with the longest patency and the lowest complications. Although various technical solutions can be adopted for constructing access to the patient's vessels, the nephrologist must bear in mind that every VA in the upper limb, lower limb or body wall needs a run-in and a run-off: currently, thrombosis of the central vessels due to the excessive widespread use of central venous catheters (CVCs) emerge as a substantial cause of hemodialysis (HD) morbidity and mortality. Moreover, as there is a risk of central vein stenosis, even 2 weeks after catheter placement, and an impaired venous outflow precludes the creation of any VA and sometimes the placement of a kidney transplant in the iliac fossa for many years, we agree with McGill et al, who in 2005 said that ''expansion of catheter access may contribute to the reduced survival of hemodialysis patients in the United States''.

Reverse mid-dilution: new way to remove small and middle molecules as well as phosphate with high intrafilter convective clearance

BACKGROUND

The removal of small and middle molecules has a relevant impact on haemodialysis (HD) patient survival. Mid-dilution (MD) is a technique combining ease of use with high diffusive-convective clearances. However, MD may increase the intrafilter blood pressure due to the high filtration fraction. We devised a new filter configuration, reverse MD, with an inverted blood inlet and outlet. We compared biochemical and technical performances of reverse MD vs standard MD.

METHODS

Eight HD patients underwent one standard MD treatment and one reverse MD. Samples for instantaneous clearance and total mass removed from dialysate spilling (urea, phosphate, beta2-microglobulin, angiogenin) were obtained. Dialysate and blood pressures in the circuit were monitored every 15 min. The reinfusion rate was set at 6 l/h for both treatments.

RESULTS

Absolute removals were very high and statistically comparable in both the configurations. Pressures were significantly lower with the reverse compared with the standard MD: inlet blood pressure was 731+/-222 and 595+/-119 mmHg in the standard and in the reverse MD, respectively. The transmembrane pressures were lower in the reverse compared with the standard MD (422+/-90 and 611+/-136 mmHg for 1st stage; 188+/-54 and 307+/-56 mmHg for 2nd stage).

CONCLUSIONS

Reverse MD could be an ideal technique for high ultrafiltration routine treatments without any external fluid reinfusion. It allows a very high removal of small and middle molecules, with relatively lower intrafilter pressures.

Impact of the Kidney Disease Outcomes Quality Initiative (KDOQI) Clinical Practice Guidelines for Bone Metabolism and Disease in a large dialysis network

BACKGROUND

The impact of the Kidney Disease Outcomes Quality Initiative (KDOQI) Clinical Practice Guidelines for Bone Metabolism and Disease in Chronic Kidney Disease has not been assessed.

METHODS

We compared albumin-adjusted serum calcium, phosphate, calcium x phosphate (Ca x P) product, and parathyroid hormone (PTH) values among active hemodialysis patients who received care at Dialysis Clinic Inc facilities during 8-month periods before (n = 9,516) and after (n = 9,543) the October 2003 release of the KDOQI guidelines. We examined the impact of missed sessions, abbreviated sessions, and patient-dietitian ratio on achievement of consistent control (defined as >or= 75% values within guideline targets) for each parameter. We also evaluated whether achievement of consistent control of a given parameter precluded control of another.

RESULTS

There was a modest decrease in mean per-patient concentration for all mineral metabolic indicators after release of the guidelines. Similarly, the proportion of values within the recommended ranges for serum calcium, phosphate, and Ca x P product increased, but remained unchanged for PTH. The likelihood of achieving consistent control for each indicator increased when other parameters were concomitantly in range. Missed dialysis sessions were associated with a lower likelihood of achieving consistent control of calcium, phosphate, and Ca x P product levels, whereas abbreviated sessions were associated inversely with consistent achievement of phosphate and Ca x P product target levels. Variations in patient-dietitian ratio had no discernible association with mineral metabolic control.

CONCLUSION

The KDOQI Clinical Practice Guidelines for Bone Metabolism and Disease had a small, but noticeable, effect in the year after their release. Additional studies should evaluate whether achievement of the prescribed target levels confers an advantage with respect to relevant clinical outcomes.

Survival on dialysis post-kidney transplant failure: results from the Scientific Registry of Transplant Recipients

BACKGROUND

A substantial number of patients return to dialysis therapy after a renal transplant fails. It is not clear whether mortality increases among patients with graft failure relative to those on the waiting list who have not yet received a kidney transplant.

METHODS

Data from the Scientific Registry of Transplant Recipients were analyzed (N = 175,436). Cox regression with time-dependent covariates was used to compare mortality between post-graft failure dialysis patients and primary transplant candidates on dialysis therapy. Mortality hazard ratios (HRs) were adjusted for age, sex, race, cause of end-stage renal disease, pre-waiting list time on dialysis therapy, calendar year of wait-listing, and organ procurement organization.

RESULTS

Overall, the post-graft failure dialysis group experienced a significant 78% greater mortality (HR, 1.78; P < 0.0001) relative to the transplant candidate group. The post-graft failure dialysis/transplant candidate HR was relatively constant across age groups, but significantly greater (P < 0.0001) among patients with diabetes (HR, 1.93) than among those without diabetes (HR, 1.69). The HR was greatest during the first week after graft failure (HR, 13.6; P < 0.0001) and decreased steadily thereafter. However, despite leveling off, the HR remained significantly elevated well after graft failure, including the 5- to 10-year period after graft failure.

CONCLUSION

Based on national data, mortality among patients on dialysis therapy after primary graft failure increases significantly relative to mortality among patients still awaiting primary kidney transplantation. Additional studies are urgently needed to define the mechanism of the increased risk and strategies to decrease mortality.

Risks of coronary artery bypass surgery in dialysis-dependent patients--analysis of the 2001 National Inpatient Sample

BACKGROUND

Dialysis patients have a high risk of cardiovascular death but may under-use coronary artery bypass grafting (CABG) because of the risk of peri-operative death. Whether operative mortality in dialysis patients has declined with contemporary techniques is uncertain. We undertook this study in order to compare peri-operative mortality in chronic dialysis (CD) and non-dialysis patients following CABG and to determine whether high levels of comorbidity in CD patients account for identified differences in operative risk.

METHODS

This study is a retrospective analysis of the 2001 National Inpatient Sample, a stratified probability sample of over seven million admissions in 33 states. Administrative data and ICD-9CM codes were used to identify dialysis patients, comorbidities, procedures and operative outcomes. Multivariable logistic regression was used to adjust for confounding.

RESULTS

In this study, 77 323 non-dialysis patients and 635 dialysis patients underwent CABG. In-hospital death occurred in 11.1% of dialysis patients compared to 3.4% of non-dialysis patients. Rates of stroke, sepsis and pneumonia were also increased in dialysis patients. After adjustment for other surgical risk factors, the odds of in-hospital death were 3.38 (2.54-4.50, P < 0.001) times higher in dialysis than non-dialysis patients.

CONCLUSIONS

Operative mortality in dialysis patients remains high despite recent advances in CABG surgery and is not explained by the high rates of comorbidity in dialysis patients. Because there is a very high risk of cardiovascular death without intervention, CABG may nevertheless be a life-saving therapy in CD patients. Randomized trials are needed to better define the optimal role of CABG in dialysis patients.

Atherosclerotic Renovascular Disease in Older US Patients Starting Dialysis, 1996 to 2001

Background— Temporal trends regarding the epidemiology of atherosclerotic renovascular disease (ARVD) in dialysis populations are poorly defined.

Methods and Results— United States Renal Data System data were used to identify patients aged 67 years or older at dialysis inception between 1996 and 2001 (n=146 973). Medicare claims in the preceding 2 years were used to identify ARVD and revascularization procedures. Prior ARVD rose from 7.1% to 11.2% between 1996 and 2001 (adjusted odds ratio [AOR], 1.68). Other associations included hypertensive end-stage renal disease (ESRD; AOR, 2.21), ESRD network (AOR, 0.44 in network 17 versus 1.00 in network 1), peripheral vascular disease (AOR, 1.65), black race (AOR, 0.44), urologic cause of ESRD (AOR, 0.57), age >85 years (AOR, 0.58), substance dependency (AOR, 0.62), and inability to ambulate or transfer (AOR, 0.67). The proportion of ARVD patients undergoing revascularization rose from 14.6% to 16.7% between 1996 and 2001 (AOR, 1.27). Other associations included hypertension (AOR, 2.10), ESRD network (AOR, 2.07 for network 13 versus 1.00 in network 1), age >85 years (AOR, 0.53), and black race (AOR, 0.54). The rise in ARVD was not reflected in the proportion of patients with renovascular disease listed as cause of ESRD on the Medical Evidence Report at dialysis inception (5.5% in 1996, 5.0% in 2001).

Conclusions— ARVD diagnoses have become more common in older patients beginning dialysis therapy. The association of demographic factors including age, race, and geographic residence with utilization patterns suggests possible barriers to care.

[Parallels in development of hemodialysis service and kidney transplantations in Lithuania during 1996-2005]

The aim of our study was to evaluate the changes in hemodialysis service, main demographic characteristics of hemodialysis patients in Lithuania during 1996-2005, and their correlation with the number of recipients on the kidney waiting list. During the study period, we annually visited all hemodialysis centers in Lithuania and collected data about all hemodialysis patients. There was a sharp increase in the number of hemodialysis centers (from 17 to 43), hemodialysis stations (from 25 to 100 per million population, P<0.001), hemodialysis patients (from 60 to 312 per million population, P<0.001), and new hemodialysis patients (from 54.3 to 95 per million population, P<0.01). The mean age of hemodialysis patients increased from 47.2+/-16.1 years in 1996 to 58.8+/-15.6 years in 2005 (P<0.001). Hemodialysis population became older. The percentage of patients aged more than 60 years increased from 22.8% to 53.2% (P<0.001) and aged more than 70 years from 5.4% to 24.4% (P<0.001). The frequency of chronic glomerulonephritis as underlying disease of end-stage renal disease decreased from 54.5% in 1996 to 21.1% in 2005 (P<0.001). There was an increase in the percentage of patients in whom end-stage renal disease was caused by diabetic (from 7.1% to 19.2%, P<0.01) and hypertensive nephropathies (from 3.1% to 13.9%, P<0.05) and chronic pyelonephritis (from 11.2% to 17.9%, P<0.01). The percentage of recipients on the kidney waiting list decreased from 71.4% in 1996 to 21.1% in 2005. In summary, during the last 9 years, hemodialysis service in Lithuania significantly expanded. The number of hemodialysis patients was continuously rising with predominance of diabetic, hypertensive, and elderly patients. Diabetic nephropathy, chronic glomerulonephritis, and pyelonephritis were the main underlying diseases of end-stage renal disease in hemodialysis patients in 2005. The percentage of recipients on the kidney waiting list decreased probably because of the rise in the number of elderly patients and patients with diabetes mellitus in Lithuanian hemodialysis population.

Dose requirements among hemodialysis patients treated with darbepoetin-alpha or epoetin-beta

BACKGROUND/AIMS

In a cohort of hemodialysis patients, we evaluated the hypothesis that weekly administration of intravenous (IV) darbepoetin-alpha (DA) was associated with lower total erythropoiesis-stimulating agent (ESA) requirements as compared to a regimen of multiple subcutaneous (SC) doses per week of epoetin-beta (EB).

METHODS

We studied 1,159 hemodialysis patients who were treated exclusively with either IV DA or SC EB across a network of Portuguese clinics during 2004. Linear regression was used to assess the adjusted relationship between the ESA regimen and weekly ESA requirements over the period of observation. Generalized estimating equations were applied in order to model the population average effects of the correlated mean weekly ESA dose for each individual. We also calculated propensity scores for the receipt of DA and assessed the relationship between ESA type and dose requirement within each quintile of the score.

RESULTS

The adjusted dose of IV DA, when expressed as a proportion of the dose used in EB-treated patients, did not differ from the dose administered to EB recipients (0.961, 95% CI 0.904, 1.021). A similar relationship was observed within each propensity score quintile.

CONCLUSIONS

Hemodialysis patients who received IV DA had dose requirements that were similar to their counterparts who were treated with SC EB. A once-weekly dosing regimen and avoidance of SC administration enhance the attractiveness of DA as an alternative to traditional ESAs. The potential for unmeasured confounding, restriction to a population that was treated with a single ESA preparation and application of a 200 IU:1 mug EB:DA dose conversion are important limitations of this study.

Dialysis and nanotechnology: now, 10 years, or never?

Nanotechnology, defined as the science of material features between 10(-9) and 10(-7) of a meter, has received extensive attention in the popular press as proof-of-concept experiments in the laboratory are published. The inevitable delay between feature articles and clinical endpoints has led to unwarranted skepticism about the applicability of the technology to current medical therapy. The theoretic advantages of micro- and nanometer scale engineering to renal replacement include the manufacture of high-hydraulic permeability membranes with implanted sensing and control structures. Recent data in membrane design and testing is presented, with a review of the challenges remaining in implementation of this technology.

Managing Complexity at Dialysis Service Centers across Europe

INTRODUCTION

Dialysis is probably one of the areas of medicine with more guidelines than any other. Issues such as dialysis dose are dealt with in those guidelines, and minimum values to be reached are defined. A target has to be set and reached by using a data-driven continuous quality improvement (CQI) approach. Data collection must be programmed and structured from the beginning.

METHODS

Fresenius started its activities as a dialysis provider in 1996, following the merger of its dialysis business with the leading service provider in the US, National Medical Care. Currently Fresenius Medical Care's European activities involve more than 320 dialysis centers located in 15 countries and treating more than 24,000 patients. Management is based on a bi-dimensional organization where line managers can rely on international functional departments. Under this framework, the CQI techniques are applied in conjunction with benchmarking in a system driven by quality targets. In order to combine clinical governance with management targets, the Balanced ScoreCard system was selected. The Balanced ScoreCard monitors the efficiency of each dialysis center compared to an ideal model, targeting maximum possible efficiency whilst having a unique target for patient outcomes.

CONCLUSION

A clear definition of targets is fundamental and activities need to be monitored and continuously improved; scientific collection of clinical data is the key.

Development of new therapies, including regeneration of the kidney, for chronic kidney diseases

The increasing number of patients on chronic hemodialysis is a great problem in the field of nephrology in Japan and Western countries. Current therapies for chronic kidney diseases (CKDs) can retard the progression of renal failure, but cannot completely stop their progression to endstage renal failure (ESRD). Many researchers are now studying new therapeutic targets for CKDs, by various methods. Furthermore, because organ donation for kidney transplantation is very limited in Japan, research on kidney regeneration is an important issue for the therapy of ESRD. To regenerate the kidney, stem cells and growth factors for the kidney are being extensively studied, although the clinical application of the results of these studies has not yet taken place.

The future of hemodialysis membranes

Hemodialytic treatment of patients with either acute or chronic renal failure has had a dramatic impact on the mortality rates of these patients. Unfortunately, this membrane-based therapy is still incomplete renal replacement, as the mortality and morbidity of these patients remain unacceptably high. Much progress must be made to improve the biocompatibility of hemodialysis membranes as well as their hydraulic and permselective properties to remove small solutes and 'middle molecules' in compact cartridges. The next directions of development will leverage materials and mechanical engineering technology, including microfluidics and nanofabrication, to further improve the clearance functions of the kidney to replicate glomerular permselectivity while retaining high rates of hydraulic permeability. The extension of membrane technology to biohybrid devices utilizing progenitor/stem cells will be another substantive advance for renal replacement therapy. The ability to not only replace solute and water clearance but also active reabsorptive transport and metabolic activity will add additional benefit to the therapy of patients suffering from renal failure. This area of translational research is rich in creative opportunities to improve the unmet medical needs of patients with either chronic or acute renal failure.

Resolving the paradigm crisis in intravenous iron and erythropoietin management

Despite the proven benefits of intravenous (i.v.) iron therapy in anemia management, it remains underutilized in the hemodialysis population. Although overall i.v. iron usage continues to increase slowly, monthly usage statistics compiled by the US Renal Data System suggest that clinicians are not implementing continued dosing regimens following repletion of iron stores. Continued therapy with i.v. iron represents a key opportunity to improve patient outcomes and increase the efficiency of anemia treatment. Regular administration of low doses of i.v. iron prevents the recurrence of iron deficiency, enhances response to recombinant human erythropoietin therapy, minimizes fluctuation of hemoglobin levels, hematocrit levels, and iron stores, and may reduce overall costs of care. This article reviews the importance of i.v. iron dosing on a regular basis in the hemodialysis patient with iron-deficiency anemia and explores reasons why some clinicians may still be reluctant to employ these protocols in the hemodialysis setting.