A single dialysis session of hemodiafiltration with sorbent-regenerated endogenous ultrafiltrate reinfusion (HFR) removes hepcidin more efficiently than bicarbonate hemodialysis: a new approach to containing hepcidin burden in dialysis patients?

Background: Most hemodialysis patients have high Hepcidin-25 levels, which may be involved in the pathogenesis of several uremic complications related to an altered iron biology. The hemodialysis procedure itself can influence Hepcidin-25 levels by removing Hepcidin-25 and maybe stimulating its production due to a pro-inflammatory effect.

Methods: To assess the relationship between dialysis-related inflammation and intradialysis changes in Hepcidin-25, we performed a crossover trial in 28 hemodialysis patients to compare the effects on serum levels of Hepcidin-25 and inflammatory markers activated during dialysis [Tumor Necrosis Factor-α (TNF-α), Interleukin-6, C-reactive protein (CRP), Pentraxin-3] of a single dialysis session using a technique capable of reducing inflammation, HFR (Hemo Filtrate Reinfusion: a hemodiafiltration system combining convection, diffusion and adsorption) or bicarbonate-dialysis using either the same low-flux membrane as in the diffusion stage of HFR (LFBD) or a high-flux membrane (HFBD).

Clinical access assessment.

Background: Vascular access guidelines recommend routine screening for the timely detection of stenosis using noninvasive methods, including clinical assessment (monitoring) and device-based surveillance relying on access blood flow (Qa) and static intra-access pressure (sVPR, static venous pressure ratio) measurements and duplex ultrasound (DU).

Methods: We reviewed the literature to see how monitoring compares with surveillance in terms of compliance with the World Health Organization's criteria for screening tests.

Results: The fundamental element of monitoring, physical examination (PE), has a fair-to-good performance in detecting stenosis in both fistulas and grafts, similar to the Qa criteria recommended in the guidelines.

The rise and fall of access blood flow surveillance in arteriovenous fistulas.

Vascular access blood flow (Qa) surveillance has been described as a typical false paradigm, an example of how new tests are sometimes adopted even without good-quality evidence of their benefits. This may be true for grafts, but not necessarily for arteriovenous fistulas. We reviewed the literature on Qa surveillance in fistulas to see whether it complies with the World Health Organization's criteria for screening tests.

Should current criteria for detecting and repairing arteriovenous fistula stenosis be reconsidered? Interim analysis of a randomized controlled trial.

Background: The vascular access guidelines recommend that arteriovenous fistulas (AVFs) with access dysfunction and an access blood flow (Qa) <300-500 mL/min be referred for stenosis imaging and treatment. Significant (>50%) stenosis, however, may be detected in a well-functioning AVF with a Qa > 500 mL/min, too, but whether it is worth correcting or not remains to be seen.

Methods: In October 2006, we began an open randomized controlled trial enrolling patients with an AVF with subclinical stenosis and Qa > 500 mL/min, to see how elective stenosis repair [treatment group (TX)] influenced access failure (thrombosis or impending thrombosis requiring access revision), or loss and the related cost compared with stenosis correction according to the guidelines, i.

In search of an optimal bedside screening program for arteriovenous fistula stenosis.

Background And Objectives: Guidelines recommend systematically screening for stenosis using various methods, but no studies so far have compared all of the options. A prospective blinded study was performed to compare the performance of several bedside tests performed during dialysis in diagnosing angiographically proven >50% fistula stenosis.

Design, Setting, Participants, & Measurements: In an unselected population of 119 hemodialysis patients with mature fistulas, physical examination (PE) was conducted; dynamic and derived static venous pressure (VAPR), blood pump flow/arterial pressure (Qb/AP) ratio, recirculation (R), and access blood flow (Qa) were measured; and angiography was performed.

Bedside screening for fistula stenosis should be tailored to the site of the arteriovenous anastomosis.

Background And Objectives: Given different sites of stenosis and access blood flow rates (Qa), the criteria for diagnosing fistula stenosis might vary according to anastomotic site. To test this, we analyzed the database of a prospective blinded study seeking an optimal bedside screening program for fistula stenosis.

Design, Setting, Participants, & Measurements: Several methods used during dialysis (physical examination [PE], dynamic and derived static venous pressure [VAPR], dialysis blood pump flow/arterial pressure ratio, and Qa measurement) to diagnose angiographically-proven >50% stenosis were assessed in an unselected population of hemodialysis patients with mature fistulae (43 at the wrist [distal fistulae], 76 at mid-forearm or the elbow [proximal fistulae]).

Hepcidin is not useful as a biomarker for iron needs in haemodialysis patients on maintenance erythropoiesis-stimulating agents.

Background: It has been suggested that hepcidin may be useful as a tool for managing iron therapy in haemodialysis (HD) patients on erythropoiesis-stimulating agents (ESA).

Methods: We used SELDI-TOF mass spectrometry assay to measure serum hepcidin-25 (Hep-25) and hepcidin-20 (Hep-20) in 56 adult HD patients on maintenance ESA to assess their ability to predict haemoglobin (Hb) response after 1 g intravenous iron (62.5 mg ferric gluconate at 16 consecutive dialysis sessions) and their relationship with markers of iron status, inflammation and erythropoietic activity.

Evaluation of hepcidin isoforms in hemodialysis patients by a proteomic approach based on SELDI-TOF MS.

The hepatic iron regulator hormone hepcidin consists, in its mature form, of 25 amino acids, but two other isoforms, hepcidin-20 and hepcidin-22, have been reported, whose biological meaning remains poorly understood. We evaluated hepcidin isoforms in sera from 57 control and 54 chronic haemodialysis patients using a quantitative proteomic approach based on SELDI-TOF-MS. Patients had elevated serum levels of both hepcidin-25 and hepcidin-20 as compared to controls (geometric means: 7.

Adding access blood flow surveillance to clinical monitoring reduces thrombosis rates and costs, and improves fistula patency in the short term: a controlled cohort study.

Background: Access blood flow (Qa) measurement is the recommended method for fistula (AVF) surveillance for stenosis, but whether it may be beneficial and cost-effective is controversial.

Methods: We conducted a 5-year controlled cohort study to evaluate whether adding Qa surveillance to unsystematic clinical monitoring (combined with elective stenosis repair) reduces thrombosis and access loss rates, and costs in mature AVFs. We prospectively collected data in 159 haemodialysis patients with mature AVFs, 97 followed by unsystematic clinical monitoring (Control) and 62 by adding Qa surveillance to monitoring (Flow).

Influence of haemodialysis on high-sensitivity C-reactive protein, lipoprotein(a), apolipoproteins A and B.

Objectives: There is debate on the influence of haemodialysis (HD) on lipoprotein(a).

Design And Methods: Lp(a), apo A, apo B and high-sensitivity C-reactive protein (hs-CRP) were measured in 46 patients pre- and post-HD.

Results: The median Lp(a) concentration significantly decreased post-HD (106 vs.

Endovascular versus surgical preemptive repair of forearm arteriovenous fistula juxta-anastomotic stenosis: analysis of data collected prospectively from 1999 to 2004.

Surgery is the traditional treatment for juxta-anastomotic stenoses in forearm arteriovenous fistulas (AVF), but percutaneous transluminal angioplasty (PTA) is a suitable alternative. No prospective comparative trials between the two have been reported to date, however. A retrospective analysis of prospectively, concurrently collected data was performed to compare the outcome and cost of surgery and PTA in the preemptive repair of juxta-anastomotic stenosis in lower forearm AVF.

Outcomes of surgical revision of stenosed and thrombosed forearm arteriovenous fistulae for haemodialysis.

Background: Surgery is an established treatment for stenosed and thrombosed forearm arteriovenous fistulae (AVFs), but the literature on its outcome is limited. We report our experience of the surgical repair of stenosis in patent and thrombosed forearm AVFs and evaluate the outcome of two procedures, proximal neo-anastomosis (NEO) vs replacement of the stenosed segment with a polytetrafluoroethylene graft interposition (GI).

Methods: Sixty-four stenosed forearm AVFs underwent surgery, 32 pre-emptively and 32 post-thrombosis.

Practice patterns in the management of arteriovenous fistula stenosis: a northern Italian survey.

Background: Clinical practice for stenosis detection and treatment in arteriovenous fistulas (AVFs) varies widely and is largely dictated by local customs and expertise.

Methods: In May 2003, a questionnaire was sent to 32 hemodialysis (HD) facilities in north-eastern Italy, to assess the prevalence of patients with an AVF; the screening criteria for stenosis; the preferred imaging technique; the timing of the intervention and the treatment modality for stenosed and thrombosed AVFs.

Results: The response rate was 87%; 2895 prevalent patients were evaluated, 86% with an AVF.

Effect of protein leaking BK-F PMMA-based hemodialysis on plasma pentosidine levels.

Background: Advanced glycation end-products (AGEs) are now considered to contribute to the middle molecule toxicity of uremia and, because they are not cleared by conventional low-flux hemodialysis, alternative strategies are needed to improve their removal.

Methods: In a prospective cross-over trial involving 18 adult chronic hemodialysis subjects, we evaluated the intradialytic removal and the long-term effect on predialysis levels of Protein-bound (PBPe) and Free (FPe) pentosidine by high-pore, protein-leaking BK-F Polymethylmethacrylate-based hemodialysis (BK-F-HD), by comparing it to hemodialysis using low-flux dialyzers (LF-HD).

Results: A single BK-F-HD session removed more PBPe, but not FPe, than LF-HD.

Central role of vasopressin in sodium/water retention in hypo- and hypervolemic nephrotic patients: a unifying hypothesis.

The underfill and overflow hypotheses are usually held as mutually exclusive mechanisms for explaining sodium/water retention in nephrotic syndrome, but neither of them is entirely convincing. In this paper, we will briefly summarize the experimental and clinical evidence in favor of and against each hypothesis. Based on our personal observations, we propose a unifying hypothesis in which underfill and overflow are subsequent stages of the disease.

Can blood flow surveillance and pre-emptive repair of subclinical stenosis prolong the useful life of arteriovenous fistulae? A randomized controlled study.

Background: Stenosis is the main cause of arteriovenous fistula (AVF) failure. It is unclear, however, if surveillance for stenosis enhances AVF function and longevity and if there is an ideal time for intervention.

Methods: In a 5-year randomized, controlled, open trial we compared blood flow surveillance and pre-emptive repair of subclinical stenoses (one or both of angioplasty and open surgery) with standard monitoring and intervention based upon clinical criteria alone to determine if the former prolonged the longevity of mature forearm AVFs.

Diagnostic accuracy of ultrasound dilution access blood flow measurement in detecting stenosis and predicting thrombosis in native forearm arteriovenous fistulae for hemodialysis.

Background: Vascular access surveillance by ultrasound dilution blood flow rate (Qa) measurement is widely recommended; however, optimal criteria for detecting stenosis and predicting thrombosis in arteriovenous fistulae (AVFs) are still not clearly defined.

Methods: In a blinded trial, we evaluated the accuracy of single Qa measurement, Qa adjusted for mean arterial pressure (Qa/MAP), and decrease in Qa over time (dQa) in detecting stenosis and predicting thrombosis in an unselected population of 120 hemodialysis subjects with native forearm AVFs (91 AVFs, located at the wrist; 29 AVFs, located at the midforearm). All AVFs underwent fistulography, which identified greater than 50% stenosis in 54 cases.

A prospective controlled trial on effect of percutaneous transluminal angioplasty on functioning arteriovenous fistulae survival.

Balloon angioplasty (PTA) is an established treatment modality for stenosis in dysfunctional arteriovenous fistulae (AVF), although most studies showing efficacy have been retrospective, uncontrolled, and nonrandomized. In addition, it is unknown whether correction of stenosis not associated with significant hemodynamic, functional, and clinical abnormality may improve survival in AVF. This study was a prospective controlled open trial to evaluate whether prophylactic PTA of stenosis not associated with access dysfunction improves survival in native, virgin, radiocephalic forearm AVF.