High volume online hemodiafiltration: a global perspective and the Brazilian experience / Hemodiafiltração on-line de alto volume: uma perspectiva global e a experiência brasileira

ABSTRACT Online hemodiafiltration (HDF) is a rapidly growing dialysis modality worldwide. In Brazil, the number of patients with private health insurance undergoing HDF has exceeded the number of patients on peritoneal dialysis. The achievement of a high convection volume was associated with better clinical imprand patient - reported outcomes confirming the benefits of HDF. The HDFit trial provided relevant practical information on the implementation of online HDF in dialysis centers in Brazil. This article aims to disseminate technical information to improve the quality and safety of this new dialysis modality.

RESUMO A hemodiafiltração (HDF) on-line é uma modalidade dialítica em rápido crescimento no mundo. No Brasil, o número de pacientes com planos de saúde privados tratados por HDF já ultrapassa aquele de pacientes em diálise peritoneal. O alcance de um alto volume convectivo associado à redução de desfechos clínicos e do risco de morte confirmam os benefícios da HDF. Dados nacionais do estudo HDFit forneceram informações práticas relevantes sobre a implementação da HDF on-line em clínicas de diálise no Brasil. O objetivo desta publicação é a disseminação de informações técnicas que possam auxiliar na utilização, com qualidade e segurança, dessa nova modalidade dialítica.

Safety and efficacy of a new covered stent in hemodialysis vascular access outflow stenosis: A Brazilian multicenter retrospective study.

BACKGROUND: Vascular stenosis commonly leads to dysfunction in hemodialysis vascular access. Although percutaneous transluminal angioplasty is an established treatment, stent utilization has increased in the last decade as an alternative solution to extend the access function. This study evaluated the safety and initial results of a new impermeable covered stent for treating vascular access outflow stenosis. METHODS: Investigators retrospectively analyzed 114 hemodialysis patients treated with polytetrafluorethylene-covered stents from September 2018 to September 2022 across four centers. Lesions treated were de novo or restenotic and located in the venous graft anastomosis, outflow segment, cephalic arch, and basilic swing point. Patients were followed by in-person physical examination at 1, 3, and 6 months, and Duplex ultrasound was performed to evaluate the vascular access circuit and in-stent restenosis. The primary efficacy endpoint was target lesion primary patency at 1, 3, and 6 months. Secondary endpoints included access circuit primary patency and secondary patency at 1, 3, and 6 months. The primary safety endpoint was freedom from local or systemic serious adverse events through 30 days post-procedure. RESULTS: Forty-four patients had thrombosed access at the initial presentation, and 41 patients presented with recurrent stenosis. The target lesion primary patency rates at 1, 3, and 6 months were 100%, 89.4%, and 74%, respectively. The access circuit primary patency rates were 100% at 1 month, 85% at 3 months, and 62.7% at 6 months. The secondary patency rates at 1, 3, and 6 months were 100%, 96.4%, and 94.6%, respectively. In the adjusted multivariate Cox regression analysis, only recurrent lesions and female gender were associated with reduced primary patency rates. No serious adverse event was observed through the first 30 days post-procedure. CONCLUSION: In this retrospective analysis, a new covered stent was shown to be safe and effective for treating peripheral outflow stenosis in vascular access.

High volume online hemodiafiltration: a global perspective and the Brazilian experience.

Online hemodiafiltration (HDF) is a rapidly growing dialysis modality worldwide. In Brazil, the number of patients with private health insurance undergoing HDF has exceeded the number of patients on peritoneal dialysis. The achievement of a high convection volume was associated with better clinical imprand patient - reported outcomes confirming the benefits of HDF. The HDFit trial provided relevant practical information on the implementation of online HDF in dialysis centers in Brazil. This article aims to disseminate technical information to improve the quality and safety of this new dialysis modality.

Characteristics and predictors of mortality on haemodialysis in Brazil: a cohort of 5,081 incident patients.

BACKGROUND: Although Brazil has one of the largest populations on haemodialysis (HD) in the world, data regarding patients' characteristics and the variables associated with risk of death are scanty. METHODS: This is a retrospective analysis of all adult patients who initiated on maintenance HD at 23 dialysis centres in Brazil between 2012 and 2017. Patients were censored after 60 months of follow-up or at the end of 2019. RESULTS: A total of 5,081 patients were included in the analysis. The median age was 59 years, 59.4% were men, 37.5% had diabetes as the cause of kidney failure. Almost 70% had a central venous catheter (CVC) as the initial vascular access, about 60% started dialysis in the hospital, and fluid overload (FO) by bioimpedance assessment was seen in 45% of patients. The 60-month survival rate was 51.4%. In the Cox regression analysis, being older (P<0.0001), starting dialysis in the hospital (P=0.016), having diabetes as the cause of kidney failure (P=0.001), high alkaline phosphatase (P=0.005), CVC as first vascular access (P=0.023), and FO (P<0.0001) were associated with higher death risk, whereas higher body mass index (P=0.015), haemoglobin (P=0.004), transferrin saturation (P=0.002), and serum albumin (P<0.0001) were associated with better survival. The same variables, except initial CVC use (P=0.14), were associated with death risk in an analysis of subdistribution proportional hazards ratio including the competing outcomes. CONCLUSIONS: The present study gives an overview of a large HD population in a developing country and identifies the main predictors of mortality, including some potentially modifiable ones, such as unplanned initiation of dialysis in the hospital and fluid overload.

Achieving high convective volume in hemodiafiltration: Lessons learned after successful implementation in the HDFit trial.

BACKGROUND AND OBJECTIVES: High-volume online hemodiafiltration (OL-HDF) associates with improved outcomes compared to hemodialysis (HD), provided adequate dosing is achieved as estimated from convective volume (CV). Achievement of high CV and its impact on biochemical indicators following a standardized protocol converting HD patients to OL-HDF has not been systematically reported. We assessed the success of implementation of OL-HDF in clinics naïve to the modality. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: We analyzed the results of the implementation of postdilution OL-HDF in patients randomized to the HDF arm of a clinical trial (impact of hemoDiaFIlTration on physical activity and self-reported outcomes: a randomized controlled trial (HDFit) trial [ClinicalTrials.gov:NCT02787161]). The day before randomization of the first patient to OL-HDF at each clinic staff started a 3-day in-person training module on operation of Fresenius 5008 CorDiax machine in HDF mode. Patients were converted from high-flux HD to OL-HDF under oversight of trainers. OL-HDF was performed over a 6-months follow-up with a CV target of 22 L/treatment. We characterized median achieved CV >22 L/treatment record and analyzed the impact of HDF on biochemical variables. RESULTS: Ninety-seven patients (mean age 53 ± 16 years, 29% with diabetes, and 11% had a catheter) from 13 clinics randomized to the OL-HDF arm of the trial were converted from HD to HDF. Median CV > 22 L/treatment was achieved in 99% (94/95) of OL-HDF patients throughout follow-up. Monthly mean CV ranged from 27.1 L to 27.5 L. OL-HDF provided an increased single pool Kt/V at 3-months (0.2 [95% CI: 0.1-0.3]) and 6-months (0.2 [95% CI: 0.1-0.4]) compared to baseline, and reduced phosphate at 3-months (-0.4 mg/dL [95% CI: -0.8 to -0.12]) of follow-up. CONCLUSIONS: High-volume online hemodiafiltration was successfully implemented with 99% of patients achieving protocol defined CV target. Monthly mean CV was consistently >22 L/treatment during follow-up. Kt/V increased, and phosphate decreased with OL-HDF. Findings resulting from a short training period in several dialysis facilities appear to suggest HDF is an easily implementable technique.

Association between extracellular volume control and survival in patients on short daily haemodialysis.

BACKGROUND: Fluid overload (FO) assessed by bioimpedance spectroscopy (BIS) is associated with higher mortality risk in maintenance haemodialysis (HD). The aim was to assess if a better management of FO through short daily haemodialysis (SDHD) could improve survival. METHODS: Retrospective analysis of patients who were on HD 3 sessions/week for at least 3 months and shifted to in-centre SDHD (5 or 6 sessions/week, 2 to 3 h/session) between July 2012 and June 2016 at 23 dialysis units in Brazil. The 12-month risk of death was analysed according to the predialysis hydration status measured before and 6 months after initiation of SDHD. Predialysis hydration status was considered adequate when FO ≤15% of extracellular volume. RESULTS: A total of 297 patients on SDHD were included in the analysis. Their median age was 57 (IQR 45-67) years, 62% were males, 44% diabetics, 57% on 6 dialysis sessions/week, with a median session duration of 130 (IQR 120-150) minutes. BIS assessment at initiation of the SDHD regimen was performed in 220 patients and FO > 15% was found in 46.4%. Twelve-month survival rates for those with FO ≤15 and > 15% before initiating SDHD were 87.4 and 88.0%, respectively (P = 0.92). BIS analysis when completing 6 months on SDHD were available for 229 patients, 26.6% with FO > 15%. The survival rates for the next 12 months (from the 6th to the 18th month of follow-up) for those with FO ≤15 and > 15% were 91.0 and 72.0%, respectively (P = 0.0006). In a Cox regression model, after adjustment for demographic, clinical and laboratory variables, FO ≤ 15% persisted associated with a lower mortality risk (hazard ratio 0.34, 95%CI 0.13-0.87). CONCLUSIONS: Moving from conventional HD to SDHD was associated with better control of excessive extracellular volume. Patients who reached or maintained predialysis fluid overload ≤15% after initiating SDHD presented a lower risk of death.

Metabolic acidosis in hemodialysis: a neglected problem in Brazil.

INTRODUCTION: Metabolic acidosis is associated with the high mortality seen in hemodialysis patients. The panorama of metabolic acidosis in hemodialysis in Brazil is unclear since 1996 when the analysis of bicarbonate levels was no longer a compulsory exam. We aimed to establish the prevalence of metabolic acidosis in a hemodialysis population and analyze the factors associated with low bicarbonate levels. METHODS: A cross-sectional study was carried out to assess the prevalence of metabolic acidosis in adults undergoing regular hemodialysis from January to April 2017, in four dialysis centers from Niteroi, Rio de Janeiro, Brazil, and surroundings. For blood gas analysis, samples of 2 mL were collected in heparinized syringes before a midweek dialysis session. RESULTS: 384 patients with a mean age of 58.1 ± 15.8 years (54.5% men and 63.0%, non-white) were included. Approximately 30% had diabetes and 48%, hypertension. Nearly 88% used primary arteriovenous fistula as vascular access. The pre-dialysis mean serum tCO2 in the midweek session was 22.7 ± 3.0 mEq/L. The prevalence rate of serum bicarbonate below DOQI recommendation (22 mEq/L or higher) was 40.3%, and 6.5% had serum bicarbonate < 18 mEq/L. The dialyzer use count and the use of low-flux dialyzers were negatively associated whereas age and the standard Kt/V values were positively associated with the serum bicarbonate levels. CONCLUSION: The findings were in agreement with global data reported in previous studies. However, because the sample was relatively small and non-representative of the Brazilian population, a more comprehensive study, addressing national data is necessary to substantiate our findings.

Early changes in serum albumin: impact on 2-year mortality in incident hemodialysis patients.

INTRODUCTION/OBJECTIVE: We evaluated the predictability of early changes in serum albumin (sAlb) on the two-year mortality of incident hemodialysis patients. METHODS: Observational, longitudinal retrospective study using the database of Fresenius Medical Care of Latin America. Adult patients starting dialysis from January/2000 to June/2004, from 25 centers were included. Changes in sAlb during the first 3 months on hemodialysis were used as the main predictor. The outcome was death from any cause. RESULTS: 1,679 incident patients were included. They were 52 ± 15 years old, 58.7% male and 21.5% diabetic, with a median sAlb of 38 g/L (bromocresol green). 923 patients had sAlb < 38 g/L (Low sAlb Group) and 756 ones had sAlb > 38.0 g/L (Adequate sAlb Group). The mortality was significantly higher in Low sAlb Group (17% vs. 11%, p < 0.001). Early changes in sAlb significantly affected two-year mortality. Factoring the Kaplan Meier curve of Low sAlb Group by the presence of an increase in sAlb uncovered of a statistically significant difference in mortality favoring the ones whose sAlb went up (19% vs. 15%, p = 0.043). Differently, patients from Adequate sAlb Group with a decrease in their sAlb had a statistically higher mortality rate (13% vs. 8%, p = 0.029). CONCLUSIONS: Early sAlb changes showed a significant predictive power on mortality at 2 years in incident hemodialysis patients. Those with low initial sAlb may have a better prognosis if their sAlb rises. In contrast, patients with satisfactory initial levels can have a worsening of their prognosis in the case of an early reduction in sAlb.

Early changes in serum albumin: impact on 2-year mortality in incident hemodialysis patients / Alterações precoces da albumina sérica: impacto sobre a mortalidade aos 2 anos em pacientes incidentes em hemodiálise

Abstract Introduction/objective: We evaluated the predictability of early changes in serum albumin (sAlb) on the two-year mortality of incident hemodialysis patients. Methods: Observational, longitudinal retrospective study using the database of Fresenius Medical Care of Latin America. Adult patients starting dialysis from January/2000 to June/2004, from 25 centers were included. Changes in sAlb during the first 3 months on hemodialysis were used as the main predictor. The outcome was death from any cause. Results: 1,679 incident patients were included. They were 52 ± 15 years old, 58.7% male and 21.5% diabetic, with a median sAlb of 38 g/L (bromocresol green). 923 patients had sAlb < 38 g/L (Low sAlb Group) and 756 ones had sAlb > 38.0 g/L (Adequate sAlb Group). The mortality was significantly higher in Low sAlb Group (17% vs. 11%, p < 0.001). Early changes in sAlb significantly affected two-year mortality. Factoring the Kaplan Meier curve of Low sAlb Group by the presence of an increase in sAlb uncovered of a statistically significant difference in mortality favoring the ones whose sAlb went up (19% vs. 15%, p = 0.043). Differently, patients from Adequate sAlb Group with a decrease in their sAlb had a statistically higher mortality rate (13% vs. 8%, p = 0.029). Conclusions: Early sAlb changes showed a significant predictive power on mortality at 2 years in incident hemodialysis patients. Those with low initial sAlb may have a better prognosis if their sAlb rises. In contrast, patients with satisfactory initial levels can have a worsening of their prognosis in the case of an early reduction in sAlb. .

Resumo Introdução/objetivo: Avaliou-se o impacto das alterações precoces na albumina sérica (sAlb) na mortalidade em 2 anos de hemodialisados incidentes. Métodos: Estudo longitudinal retrospectivo usando o banco de dados da Fresenius Medical Care da América Latina. Adultos iniciando diálise de janeiro de 2000 a junho de 2004, originados de 25 centros de diálise foram incluídos. Mudanças na sAlb durante os primeiros 3 meses em hemodiálise foram usadas como a variável de principal interesse. O desfecho foi morte por qualquer causa. Resultados: Um total de 1.679 pacientes incidentes foi incluído. Eles tinham 52 ± 15 anos, 58,7% eram do sexo masculino e 21,5%, diabéticos, com sAlb mediana de 38,0 g/L (bromocresol verde). Novecentos e vinte e três pacientes tiveram sAlb ≤ 38,0 g/L (Grupo sAlb baixa) e 756, sAlb > 38,0 g/L (Grupo sAlb adequada). A mortalidade foi significativamente maior no Grupo sAlb baixa (17% vs. 11%, p < 0,001). Alterações precoces na sAlb afetaram significativamente a mortalidade em dois anos. Fatoração da curva de Kaplan-Meier do Grupo sAlb baixa pela presença de um aumento na sAlb revelou uma diferença na mortalidade favorecendo aqueles cuja sAlb subiu (19% vs. 15%, p = 0,043). Em contraste, pacientes do Grupo sAlb adequada que mostraram diminuição na sAlb tiveram maior taxa de mortalidade (13% vs. 8%, p = 0,029). Conclusão: Alterações precoces na sAlb mostraram um poder previsor significativo sobre a mortalidade em 2 anos em hemodialisados incidentes. Casos com sAlb inicial baixa melhoraram seu prognóstico quando houve elevação na sAlb, enquanto que aqueles com níveis iniciais satisfatórios tiveram um agravamento de seu prognóstico quando houve redução na sAlb. .