Does hemodiafiltration reduce vascular stiffness measured by aortic pulse wave velocity compared with high‐flux hemodialysis?

Hemodialfiltration (HDF) has been reported to reduce the frequency of intradialytic hypotension compared with hemodialysis (HD). We wished to determine whether HDF resulted in improvement of arterial stiffness compared with HD. We reviewed peripheral blood pressure and pulse wave velocity measurements in a cross‐sectional analysis of stable HDF and HD outpatients. One hundred forty‐one HDF patients were matched to 148 HD patients in terms of age, sex, prevalence of diabetes, peripheral blood pressure, and body mass. Pulse wave velocity was not different between the HD and HDF cohorts (median 9.1 [8.0–10.7] m/s vs. 9.7 [8.5–11.6] m/s). Similarly, there were no differences in central aortic pressure (149.2 ± 30.9 mmHg vs. 151.9 ± 35.2 mmHg), or aortic (39 [25.1–51.2]% vs. 38.6 [25.8–51.4]%) and brachial (3.8 [?24.3 to 26.9]% vs. 3 [?22.4 to 27.1]%) augmentation indices, respectively. Pulse wave velocity did not differ between adult patients treated by HD and HDF, and similarly, there were no differences in central aortic pressure, aortic or brachial augmentation indices, and cardiac diastolic perfusion. Our study suggests that HDF does not appear to offer any benefit over HD in terms of vascular stiffness.     

Reprocessing high‐flux polysulfone dialyzers does not negatively impact solute removal in short‐daily online hemodiafiltration

There are no studies evaluating the impact of dialyzer reprocessing on solute removal in short‐daily online hemodiafiltration (OL‐HDF). Our aim was to evaluate the impact of dialyzer reuse on solute removal in daily OL‐HDF and compare with that in high‐flux short‐daily hemodialysis (SDH). Fourteen patients undergoing a SDH program were included. Pre‐dialysis and post‐dialysis blood samples and effluent dialysate were collected in the 1st, 7th, and 13th dialyzer uses in SDH sessions and in daily OL‐HDF sessions. Directly quantified small solute (urea, phosphorus, creatinine, and uric acid) total mass removal (TM_DQ) and clearance (K_DQ) were similar when the 1st, 7th, and 13th dialyzer SDH uses were compared with the 1st, 7th, and 13th daily OL‐HDF uses. TM_DQ and K_DQ of small solutes were similar among analyzed dialyzer uses in SDH sessions and in daily OL‐HDF sessions. β₂‐Microglobulin TM_DQ and K_DQ were statistically higher in daily OL‐HDF dialyzer uses than in the respective SDH uses. There was no difference in β₂‐microglobulin TM_DQ and K_DQ among dialyzer uses in daily OL‐HDF sessions or in SDH sessions. In daily OL‐HDF, albumin loss was significantly different among dialyzer uses (P < 0.001), being lower in the 7th and 13th dialyzer uses than in the first use. Dialyzer reprocessing did not impair solute extraction in daily OL‐HDF. β₂‐Microglobulin removal was greater in daily OL‐HDF than in SDH sessions, without significant differences in other solutes extraction. There was a significant reduction in intradialytic albumin loss with dialyzer reprocessing in daily OL‐HDF sessions.     

Assessment of subjective and hemodynamic tolerance of different high‐ and low‐flux dialysis membranes in patients undergoing chronic intermittent hemodialysis: A randomized controlled trial

Clinical experience and experimental data suggest that intradialytic hemodynamic profiles could be influenced by the characteristics of the dialysis membranes. Even within the worldwide used polysulfone family, intolerance to specific membranes was occasionally evoked. The aim of this study was to compare hemodynamically some of the commonly used polysulfone dialyzers in Switzerland. We performed an open‐label, randomized, cross‐over trial, including 25 hemodialysis patients. Four polysulfone dialyzers, A (Revaclear high‐flux, Gambro, Stockholm, Sweden), B (Helixone high‐flux, Fresenius), C (Xevonta high‐flux, BBraun, Melsungen, Germany), and D (Helixone low‐flux, Fresenius, Bad Homburg vor der Höhe, Germany), were compared. The hemodynamic profile was assessed and patients were asked to provide tolerance feedback. The mean score (±SD) subjectively assigned to dialysis quality on a 1–10 scale was A 8.4 ± 1.3, B 8.6 ± 1.3, C 8.5 ± 1.6, D 8.5 ± 1.5. Kt/V was A 1.58 ± 0.30, B 1.67 ± 0.33, C 1.62 ± 0.32, D 1.45 ± 0.31. The low‐ compared with the high‐flux membranes, correlated to higher systolic (128.1 ± 13.1 vs. 125.6 ± 12.1 mmHg, P < 0.01) and diastolic (76.8 ± 8.7 vs. 75.3 ± 9.0 mmHg; P < 0.05) pressures, higher peripheral resistance (1.44 ± 0.19 vs. 1.40 ± 0.18 s × mmHg/mL; P < 0.05) and lower cardiac output (3.76 ± 0.62 vs. 3.82 ± 0.59 L/min; P < 0.05). Hypotension events (decrease in systolic blood pressure by >20 mmHg) were 70 with A, 87 with B, 73 with C, and 75 with D (P < 0.01 B vs. A, 0.05 B vs. C and 0.07 B vs. D). The low‐flux membrane correlated to higher blood pressure levels compared with the high‐flux ones. The Helixone high‐flux membrane ensured the best efficiency. Unfortunately, the very same dialyzer correlated to a higher incidence of hypotensive episodes.     

Vascular access‐related infection in nocturnal home hemodialysis

Frequent hemodialysis is associated with increased vascular access adverse events. We hypothesized that bacteremia would be more frequent in patients with central venous catheter (CVC) than arteriovenous fistula or arteriovenous graft (AVF/AVG) in nocturnal home hemodialysis (NHHD). We reviewed blood culture reports and concurrent clinical data for a cohort of one hundred eighty‐seven NHHD patients between January 1, 2006 and June 30, 2012. The primary outcome was time to first bacteremia, technique failure, or death after commencing NHHD. Types of bacteremia and clinical consequences were analyzed. Analyses were adjusted for a priori defined confounders. One hundred eighty‐seven patients were included with a total follow up of six hundred five patient years. Initial vascular access was AVF in seventy‐eight (42%) patients, AVG in eleven (6%) patients, and CVC in ninety‐eight (52%) patients. A total of 79.3% of patients with a CVC reached the composite endpoint of bacteremia, technique failure, or death in the study period; 44.5% of patients with an AVF or AVG reached this composite endpoint. Adjusted time to first bacteremia, technique failure, or death was significantly shorter in patients with initial CVC access (hazard ratio 2.42, 95% confidence interval 1.50–3.90, p < 0.001). Risk factors for bacteremia were comorbid status quantified by the Charlson Comorbidity Index (p < 0.001) and diabetes (p < 0.001). Coagulase negative staphylococcus was the commonest organism cultured accounting for 51.4% bacteremias. The second commonest organism was staphylococcus aureus (20.3% bacteremias). Patients undergoing NHHD with a CVC have a shorter duration to first infection, technique failure, or death than those with permanent vascular access.     

Patient mood flux on‐ and off‐hemodialysis

Mood in hemodialysis patients is most often evaluated off‐dialysis, possibly underestimating mood during dialysis. We compared mood in patients on‐ and off‐dialysis using the Positive and Negative Affect Schedule for 6 consecutive days. Initially, scores are normal, but subsequently positive affect falls below, and negative affect increases above, off‐dialysis values, suggesting increasing depression and anxiety, particularly in women. Quality‐of‐life questions confirm the effects of the dialysis session on mood. Prevalence and severity of depression evaluated off‐dialysis, or once only, may be underestimated, especially in women, because hemodialysis patients undergo mood swings centering on the dialysis session. Focusing insight on the dialysis session could improve coping among patients and caretakers.     

Low‐cost solution to on‐line color filter array demosaicking

The article introduces a low‐cost algorithm for improving the demosaicking process in the texture areas such as one‐pixel patterns. The algorithm first detects difficult texture regions. After the detection process is completed, the algorithm demosaicks the texture areas using special demosaicking operations whereas non‐texture regions are restored using some of the existing demosaicking approaches. In this way, the quality of the texture areas in demosaicked images can be improved up to 70% while only little increasing the computational complexity of the original demosaicking solution. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 232–243, 2007     

Surveillance cultures of tunneled cuffed catheter exit sites in chronic hemodialysis patients are of no benefit

Catheter-related infections are a major cause of morbidity and mortality in hemodialysis (HD) patients. This study evaluated the utility of surveillance swab cultures (Ssc) of tunneled cuffed catheter (TCC) exit sites as a prediction and prevention strategy for infection. A 6-month prospective-controlled trial with 94 chronic HD patients with a TCC who received monthly Ssc and were stratified by dialysis day into topical therapy based on Ssc results (Group A) or no therapy (Group B). Outcomes were exit site infection (ESI) and catheter-associated bacteremia (CAB). The overall monthly prevalence of positive Ssc was 14.9%. There was no difference in the number of positive Ssc (17.7% vs. 11.6%, p > 0.05) or ESI (19.6% vs.16.3%, p > 0.05) between Groups A and B, respectively. Catheter-associated bacteremia was higher in Group A (17.7% vs. 4.7%, p = 0.05). There were significantly more ESI in the patients treated for a positive Ssc. In Group A, the incidence of ESI was significantly higher in those treated for a positive vs. negative Ssc (55% vs. 12%, p = 0.009) and CAB rates trended higher with positive Ssc (22.2% vs. 16.7%, p > 0.05). The strategy of treating positive surveillance cultures is not beneficial. Positive Ssc do not predict the occurrence of catheter-related infection, and treatment of these cultures may lead to increased infection rates.     

Use of the anion gap and intermittent hemodialysis following continuous hemodiafiltration in extremely high dose acute‐on‐chronic lithium poisoning: A case report

A 35‐year‐old woman intentionally took 40,000 mg of lithium carbonate, and she was transferred to our hospital with nausea, vomiting, and diarrhea. She was diagnosed as having bipolar disorder 10 years ago and was receiving oral lithium therapy. Blood test results on arrival were remarkable for a negative anion gap of ?2.1 and later, the serum lithium level turned out to be as high as 15.4 mEq/L. Intubation was required because of disrupted consciousness, and continuous hemodiafiltration (CHDF) was immediately started in the intensive care unit to obtain constant removal of lithium. After adding intermittent hemodialysis (IHD) twice during the daytime to accelerate the lithium clearance, CHDF became unnecessary on day 4, and she was extubated on day 6 with complete recovery of consciousness. Close monitoring of the patient data showed recovery of the decreased anion gap as indicator of the serum lithium level reduction. On day 36, she was discharged without any complication and sequela. The current case highlighted the effective use of CHDF between IHD sessions to prevent the rebound elevation of lithium and the role of the anion gap as a surrogate marker of serum lithium concentration during the treatment.     

FGF‐23 and cognitive performance in hemodialysis patients

Although cognitive impairment is common in hemodialysis patients, the etiology of and risk factors for its development remain unclear. Fibroblast growth factor 23 (FGF‐23) levels are elevated in hemodialysis patients and are associated with increased mortality and left ventricular hypertrophy. Despite FGF‐23 being found within the brain, there are no prior studies assessing whether FGF‐23 levels are associated with cognitive performance. We measured FGF‐23 in 263 prevalent hemodialysis patients in whom comprehensive neurocognitive testing was also performed. The cross‐sectional association between patient characteristics and FGF‐23 levels was assessed. Principal factor analysis was used to derive two factors from cognitive test scores, representing memory and executive function, which carried a mean of 0 and a standard deviation of 1. Multivariable linear regression adjusting for age, sex, education status, and other relevant covariates was used to explore the relationship between FGF‐23 and each factor. Mean age was 63 years, 46% were women and 22% were African American. The median FGF‐23 level was 3098 RU/mL. Younger age, lower prevalence of diabetes, longer dialysis vintage, and higher calcium and phosphorus were independently associated with higher FGF‐23 levels. Higher FGF‐23 was independently associated with a lower memory score (per doubling of FGF‐23, β = ?0.08 SD [95% confidence interval, CI: ?0.16, ?0.01]) and highest quartile vs. lowest quartile (β = ?0.42 SD [?0.82, ?0.02]). There was no definite association of FGF 23 with executive function when examined as a continuous variable (β = ?0.03 SD [?0.10, 0.04]); however, there was a trend in the quartile analysis (β = ?0.28 SD [?0.63, 0.07], P = 0.13, for 4th quartile vs. 1st quartile). FGF‐23 was associated with worse performance on a composite memory score, including after adjustment for measures of mineral metabolism. High FGF‐23 levels in hemodialysis patients may contribute to cognitive impairment.     

Effect of dialysis dose and membrane flux on hemoglobin cycling in hemodialysis patients

Many studies found that hemoglobin (Hb) fluctuation was closely related to the prognosis of the maintenance hemodialysis patients. We investigated the association of factors relating dialysis dose and dialyzer membrane with Hb levels. We undertook a randomized clinical trial in 140 patients undergoing thrice‐weekly dialysis and assigned patients randomly to a standard or high dose of dialysis; Hb level was measured every month for 12 months. In the standard‐dose group, the mean (±SD) urea reduction ratio was 65.1% ± 7.3%, the single‐pool Kt/V was 1.26 ± 0.11, and the equilibrated Kt/V was 1.05 ± 0.09; in the high‐dose group, the values were 73.5% ± 8.7%, 1.68 ± 0.15, and 1.47 ± 0.11, respectively. The standard deviation (SD) and residual SD (liner regression of Hb) values of Hb were significantly higher in the standard‐dose group and low‐flux group. The percentage achievement of target Hb in the high‐dose dialysis group and high‐flux dialyzer group was significantly higher than the standard‐dose group and low‐flux group, respectively. Patients undergoing hemodialysis thrice weekly appear to have benefit from a higher dialysis dose than that recommended by current KDQQI (Kidney Disease Qutcome Quality Initiative) guidelines or from the use of a high‐flux membrane, which is in favor of maintaining stable Hb levels.     

Clearance of myoglobin by high cutoff continuous veno‐venous hemodialysis in a patient with rhabdomyolysis: A case report

Continuous veno‐venous hemodialysis using high cutoff filters (HCO‐CVVHD) is a promising technique, which may be effective to decrease the extremely high level of circulating myoglobin in patients with rhabdomyolysis (RM). Here, we report a patient with RM caused by heat stroke who was successfully treated by HCO‐CVVHD. A male patient received HCO‐CVVHD with 4 L/h dialysate for 5 days and then pre‐dilution continuous veno‐venous hemofiltration (CVVH) at a dose of 4 L/h until recovery of renal function. The clearance of myoglobin and albumin at 5 minutes, and at 4, 12, and 24 hours were calculated. The serum myoglobin level decreased from a peak of 25,400 ng/mL on admission to 133 ng/mL at discharge. During HCO‐CVVHD, the mean clearances of serum myoglobin at four timepoints were 61.3 (range, 61.0–61.6), 52.3 (38.9–65.8), 47.3 (46.8–47.9), and 43.7 (39.5–48.0) mL/min, respectively, and the mean clearances of albumin were 12.4 (range, 11.8–13.1), 3.1 (2.5–3.8), 1.2 (1.0–1.4), and 0.8 (0.6–1.0) mL/min, respectively. During CVVH, the clearance rates of myoglobin at 5 minutes and 24 hours were 17.0 and 3.8 mL/min, respectively, with a negligible clearance of albumin. HCO‐CVVHD can effectively decrease serum myoglobin in patients with RM because of much higher clearance of myoglobin than CVVH. However, attention should be paid to albumin loss during HCO‐CVVHD.     

Impact of advanced dialysis technology on the prevalence of dialysis‐related amyloidosis in long‐term maintenance dialysis patients

Dialysis‐related amyloidosis (DRA) is a unique type of amyloidosis (beta‐2 microglobulin) predominantly in end‐stage renal disease. Its clinical manifestations add to increased morbidity and reduced quality of life. There seems to be a relative risk reduction in DRA manifestations when hemodialysis (HD) patients are treated with advanced HD technology, but changes of the course of DRA are uncertain. The aim of our investigation was to evaluate the prevalence and severity of carpal tunnel syndrome (CTS) in long‐term dialysis patients receiving either conventional or high‐flux, online‐produced ultrapure dialysis fluid. The cross‐sectional study included 147 HD patients (at least 10 years). The definitive diagnosis of CTS was made histologically or by the coexistence of CTS with other radiological DRA manifestations (bone cysts, arthropathies). The two HD patient groups did not differ significantly in age at start of HD, gender, major co‐morbid diseases, anuria, and dialysis vintage. The conventional HD group had significantly higher circulating beta‐2 microglobulin and C‐reactive protein (CRP) levels. The prevalence of DRA was 68% for the conventional HD group and 28% for the advanced HD group. Duration of dialysis treatment was the only significant risk factor for the development of clinical DRA manifestations in both study groups, but CTS, bone cysts, or arthropathies occurred significantly earlier in conventional HD patients. The prevalence and severity of DRA have decreased with advances in dialysis technology during the last two decades, although its occurrence is simply delayed.     

Post‐hemodialysis dosing of 1 vs. 2 g of ceftazidime in anuric end‐stage renal disease patients on low‐flux dialysis and its pharmacodynamic implications on clinical use

Ceftazidime is a cost‐effective antimicrobial against Gram‐negative pathogens associated with sepsis in end‐stage renal disease (ESRD) hemodialysis patients with potential for wider use with the advent of ceftazidime‐avibactam. Dosing ceftazidime post‐hemodialysis appears attractive and convenient, but limited in vivo data on pharmacodynamic efficacy (PE) attainment, defined as >70% of the interdialytic period drug concentrations exceed susceptible pathogens minimal inhibitory concentrations (MICs) (%TMIC), warrants further assessment. We therefore evaluated PE and tolerability of 1 against 2 g regime in anuric ESRD patients on low‐flux hemodialysis. Two doses of 1 or 2 g ceftazidime were administered post‐hemodialysis prior to 48‐ and 72‐hour interdialytic intervals in ESRD inpatients without active infections. Peak and trough concentrations (mg/L) were assayed using a validated liquid chromatography–tandem mass spectrometry method. Proportion of patients achieving PE for known pathogens with MICs ≤ 8 mg/L and adverse effects were assessed. Six (43%) and eight (57%) adult patients received 1 and 2 g dose, respectively. Median (25th–75th percentile), peak, 48‐ and 72‐hour trough ceftazidime concentrations were 78 (60–98) vs. 158 (128–196), 37 (23–37) vs. 49 (39–71), and 13 (12–20) vs. 26 (21–41) mg/L, respectively, resulting in 100% TMIC for both doses. One patient on the 1‐g dose experienced mild pruritus. Reliable and safe PE attainment over both 48‐ and 72‐hour interdialytic interval was achievable with 1 g of ceftazidime dosed post‐hemodialysis. The 2 g dose was equally effective and well tolerated but may not be necessary. These findings need validation in non‐anuric patients, high‐flux hemodialysis, and during avibactam co‐administration.     

Weekly high‐dose ergocalciferol to correct vitamin D deficiency/insufficiency in hemodialysis patients: A pilot trial

Controversy exists on which vitamin D (D2 or D3) and which dosage scheme is the best to obtain and maintain adequate 25 OH D levels in dialysis patients safely. We tried to determine whether high‐dose vitamin D2 supplementation could obtain optimal vitamin D status without inducing hypercalcemia. We studied 82 patients on dialysis not taking active vitamin D therapy and supplemented them with oral vitamin D2 72,000 IU/week for 12 weeks followed by 24,000 IU/week as maintenance therapy during 36 weeks. By week 12, serum 25(OH)D increased from 15.2 ± 5.4 to 42.5 ± 13.2 ng/mL (P < 0.01) at week 12 and remained optimal (34.7 ± 12.0); 84.8% of the patients reached values ≥30 ng/mL. iPTH and alkaline phosphatase did not change at 48 weeks compared with baseline, but bone alkaline phosphatase decreased significantly (54.3 ± 46.0 to 44.3 ± 25.0; P = 0.02). Uncorrected serum Ca increased significantly at the end of follow‐up (9.03 ± 0.42 to 9.14 ± 0.62; P = 0.04); hypercalcemia was presented in two patients in the first control visit (week 12), in one patient in the second control (week 30), and in one patient in the third control (week 48). In 222 serum calcium determinations during follow‐up, hypercalcemia was observed in only 1.8% of cases. This vitamin D2 oral regimen with initial high doses was safe and sufficient to obtain and maintain optimal serum 25(OH)D concentrations and prevent vitamin D insufficiency in chronic kidney disease patients on dialysis.     

Approach to prophylactic measures for central venous catheter‐related infections in hemodialysis: A critical review

Vascular access is the major risk factor for bacteremia, hospitalization, and mortality among hemodialysis (HD) patients. The type of vascular access most associated with bloodstream infection is central venous catheter (CVC). The incidence of catheter‐related bacteremia ranges between 0.6 and 6.5 episodes per 1000 catheter days and increases linearly with the duration of catheter use. Given the high prevalence of CVC use and its direct association with catheter‐related bacteremia, which adversely impacts morbidity and mortality rates and costs among HD patients, several prevention measures aimed at reducing the rates of CVC‐related infections have been proposed and implemented. As a result, a large number of clinical trials, systematic reviews, and meta‐analyses have been conducted in order to assess the effectiveness, clinical applicability, and long‐term adverse effects of such measures. In the following article, prophylactic measures against CVC‐related infections in HD patients and their possible advantages and limitations will be discussed, and the more recent literature on clinical experience with prophylactic antimicrobial lock therapy in HD CVCs will be reviewed.     

Advances in Hydrogels in Organoids and Organs‐on‐a‐Chip

Significant advances in materials, microscale technology, and stem cell biology have enabled the construction of 3D tissues and organs, which will ultimately lead to more effective diagnostics and therapy. Organoids and organs‐on‐a‐chip (OOC), evolved from developmental biology and bioengineering principles, have emerged as major technological breakthrough and distinct model systems to revolutionize biomedical research and drug discovery by recapitulating the key structural and functional complexity of human organs in vitro. There is growing interest in the development of functional biomaterials, especially hydrogels, for utilization in these promising systems to build more physiologically relevant 3D tissues with defined properties. The remarkable properties of defined hydrogels as proper extracellular matrix that can instruct cellular behaviors are presented. The recent trend where functional hydrogels are integrated into organoids and OOC systems for the construction of 3D tissue models is highlighted. Future opportunities and perspectives in the development of advanced hydrogels toward accelerating organoids and OOC research in biomedical applications are also discussed.     

Obstructive sleep apnea in incremental hemodialysis: Determinants,consequences, and impact on survival

Sleep disorders are common in hemodialysis patients, although causes and consequences remain unclear. We sought to establish prevalence, determinants, and outcomes of sleep disturbances in patients receiving incremental dialysis. One hundred two unselected patients undergoing incremental high‐flux hemodialysis or hemodiafiltration underwent limited overnight sleep study. Large subsets underwent echocardiography, interdialytic ambulatory blood pressure monitoring, and brain natriuretic peptide measurements. Patients were followed up to 44 months. Full sleep data were obtained in 91 patients. All had sleep disturbance as evidenced by an apnea–hypopnea index >5/min. We defined major obstructive sleep apnea (MOSA) as an apnea–hypopnea index ≥15, together with either significant oxygen desaturation or symptoms of daytime sleepiness. Forty patients met these criteria. Significant independent predictors of MOSA were age <65 years, male gender, has diabetes, and has a brain natriuretic peptide >2500 pg/mL. Mean ambulatory blood pressure and left ventricular mass index were significantly higher in these patients. In a model controlling for body mass index, high C‐reactive protein, and the presence of cancer, MOSA was associated with a twofold increased risk of mortality, although this did not reach statistical significance. MOSA was common, and was associated with hypertension and high left ventricular mass index. Whether obstructive sleep apnea contributes to the high mortality remains to be firmly established.