Relevance of a skilled vascular surgeon and optimized facility practices in the long-term patency of arteriovenous fistulas: a prospective study / Relevância de um cirurgião vascular qualificado e práticas hospitalares otimizadas na patência a longo prazo das fístulas arteriovenosas: um estudo prospectivo

Abstract Introduction: Arteriovenous fistulas (AVF) are the best hemodialysis vascular accesses, but their failure rate remains high. Few studies have addressed the role of the vascular surgeon's skills and the facility's practices. We aimed to study these factors, with the hypothesis that the surgeon's skills and facility practices would have an important role in primary failure and patency rates at 12 months, respectively. Methods: This was a single-center, prospective cohort study carried out from March 2005 to March 2017. Only incident patients were included. A single surgeon made all AVFs, either in the forearm (lower) or the elbow (upper). Vascular access definitions were in accordance with the North American Vascular Access Consortium. Results: We studied 113 AVFs (65% lower) from 106 patients (39% diabetics, 58% started with catheter). Time to first connection was 21.5 days (IR: 14 - 31). Only 14 AVFs (12.4%) underwent primary failure and 18 failed during the first year. Functional primary patency rate was 80.9% (SE 4.1) whereas primary unassisted patency rate, which included PF, was 70.6% (4.4). Logistic regression showed that diabetes (OR = 3.3, 95%CI 1.38 - 7.88, p = .007) and forearm location (OR = 3.03, 95CI% 1.05 - 8.76, p = 0.04) were predictors of AVF failure. Patency of lower and upper AVFs was similar in non-diabetics, while patency in diabetics with lower AVFs was under 50%. (p = 0.003). Conclusions: Results suggest that a long-lasting, suitable AVF is feasible in almost all patients. The surgeon's skills and facility practices can have an important role in the long term outcome of AVF.

Resumo Introdução: Fístulas arteriovenosas (FAV) são os melhores acessos vasculares para hemodiálise, mas sua taxa de falhas permanece alta. Poucos estudos abordaram o papel das habilidades do cirurgião vascular e das práticas hospitalares. Nosso objetivo foi avaliar esses fatores, com a hipótese de que as habilidades do cirurgião e as práticas hospitalares teriam um papel importante nas taxas de falhas primárias e perviedade em 12 meses, respectivamente. Métodos: Este foi um estudo de coorte prospectivo de um único centro, realizado de março de 2005 a março de 2017. Apenas os pacientes incidentes foram incluídos. Um único cirurgião fez todas as FAVs, seja no antebraço (inferior) ou no cotovelo (superior). As definições de acesso vascular estavam de acordo com o Consórcio Norte-Americano de Acesso Vascular. Resultados: Estudamos 113 FAVs (65% inferiores) de 106 pacientes (39% diabéticos, 58% começaram com cateter). O tempo até a primeira conexão foi de 21,5 dias (RI: 14 - 31). Apenas 14 FAV (12,4%) tiveram falha primária e 18 falharam durante o primeiro ano. A taxa de patência funcional primária foi de 80,9% (SE 4,1), enquanto a taxa de permeabilidade primária não assistida, que incluiu FP, foi de 70,6% (4,4). A regressão logística mostrou que o diabetes (OR = 3,3, 95% IC 1,38 - 7,88, p = 0,007) e localização no antebraço (OR = 3,03, 95% IC 1,05 - 8,76, p = 0,04) foram preditores de falha da FAV. A patência das FAVs inferior e superior foi semelhante em não-diabéticos, enquanto a perviedade em diabéticos com FAV inferior foi menor que 50%. (p = 0,003). Conclusões: Nossos resultados sugerem que uma FAV duradoura e adequada é viável em quase todos os pacientes. As habilidades do cirurgião e das práticas hospitalares podem ter um papel importante no resultado a longo prazo da FAV.

Relevance of a skilled vascular surgeon and optimized facility practices in the long-term patency of arteriovenous fistulas: a prospective study.

INTRODUCTION: Arteriovenous fistulas (AVF) are the best hemodialysis vascular accesses, but their failure rate remains high. Few studies have addressed the role of the vascular surgeon's skills and the facility's practices. We aimed to study these factors, with the hypothesis that the surgeon's skills and facility practices would have an important role in primary failure and patency rates at 12 months, respectively. METHODS: This was a single-center, prospective cohort study carried out from March 2005 to March 2017. Only incident patients were included. A single surgeon made all AVFs, either in the forearm (lower) or the elbow (upper). Vascular access definitions were in accordance with the North American Vascular Access Consortium. RESULTS: We studied 113 AVFs (65% lower) from 106 patients (39% diabetics, 58% started with catheter). Time to first connection was 21.5 days (IR: 14 - 31). Only 14 AVFs (12.4%) underwent primary failure and 18 failed during the first year. Functional primary patency rate was 80.9% (SE 4.1) whereas primary unassisted patency rate, which included PF, was 70.6% (4.4). Logistic regression showed that diabetes (OR = 3.3, 95%CI 1.38 - 7.88, p = .007) and forearm location (OR = 3.03, 95CI% 1.05 - 8.76, p = 0.04) were predictors of AVF failure. Patency of lower and upper AVFs was similar in non-diabetics, while patency in diabetics with lower AVFs was under 50%. (p = 0.003). CONCLUSIONS: Results suggest that a long-lasting, suitable AVF is feasible in almost all patients. The surgeon's skills and facility practices can have an important role in the long term outcome of AVF.

¿Puede establecerse hoy un valor de fosfatemia como indicador de calidad del tratamiento dialítico? / Can a phosphatemia value be established today as an indicator of the quality of the dialysis treatment?

INTRODUCCIÓN: El trastorno del metabolismo óseo y mineral constituye una grave complicación de la IRC. Respecto al fósforo, las nuevas Guías KDIGO sugieren disminuirla hiperfosfatemia, sin recomendar un valor determinado. Sin embargo, en Argentina se continúa utilizando como indicador de calidad dialítica (IndCalDial) un valor de fósforo igual o inferior a 5 mg.dl. Nuestro objetivo fue evaluar si un valor fijo de fosfatemia es válido como IndCalDial. MATERIAL Y MÉTODOS: Se realizó un estudio multicéntrico, de corte transversal. Se incluyeron pacientes mayores de 18 años, con más de 90 días en hemodiálisis crónica. Se tabularon datos demográficos y de laboratorio. Según el reactivo empleado en la determinación de fósforo, en 4 centros el límite superior de referencia fue 4.5 mg.dl (Grupo F4.5) y en tres 5.6 mg.dl (Grupo F5.6). RESULTADOS: Se incluyeron 334 pacientes. Edad, sexo, porcentaje con FAV, diabéticos, tiempo en diálisis, Kt/V, Hemoglobina y Albúmina, resultaron semejantes a los del Registro Nacional de Diálisis. La mediana de fosfatemia fue 5.2 mg.dl, (rango: 2.3 a 10.6). Los pacientes hiperfosfatémicos fueron más jóvenes y presentaron mejores niveles de Albúmina. De considerarse como IndCalDial: Fósforo menor a 5 mg.dl, 21 pacientes del Grupo F4.5 (n=154) con fosfatemia entre 4.5 y 5.0 mg.dl no recibirían tratamiento, mientras que en el Grupo F5.6 (n=180), 32 pacientes con fosfatemia entre 5.1 y 5.6 mg.dl deberían recibir tratamiento, a pesar de presentar normofosfatemia. CONCLUSIONES: Debería estandarizarse la determinación de fosfatemia, previo a utilizar un valor fijo como IndCalDial

¿podemos hablar hoy de un valor de fósforo como indicador de la calidad del tratamiento dialítico? / Can we speak today of a phosphorus value as an indicator of dialysis treatment quality?

Introducción: El trastorno del metabolismo óseo y mineral constituye una grave complicación de la insuficiencia renal crónica. Respecto al fósforo, las nuevas Guías KDIGO sugieren disminuir la hiperfosfatemia, sin recomendar un valor determinado. Sin embargo, en Argentina se utiliza como indicador de calidad dialítica (IndCalDial) un valor de fósforo igual o inferior a 5 mg/dL. Nuestro objetivo fue evaluar si dicho objetivo es actualmente válido como IndCalDial. Material y métodos: Estudio multicéntrico, de corte transversal. Se incluyeron pacientes mayores de 18 años, con más de 90 días en hemodiálisis. Se tabularon datos demográficos y de laboratorio, comparándose normofosfatémicos contra hiperfosfatémicos. Según el método, en 3 centros el límite superior de referencia fue 4.5 mg/dL y en cuatro 5.6 mg/dL, éstos últimos se analizaron como grupo separado F 5.6. Resultados: Se incluyeron 333 pacientes. Edad, sexo, porcentaje FAV, diabéticos, tiempo en diálisis, Kt/V, Hemoglobina y Albumina, fueron semejantes a los datos del registro. La mediana de fosfatemia fue 5.2 mg/dL, (rango: 2.3 a 10.6). Los pacientes hiperfosfatémicos presentaron menor edad, menos tiempo en diálisis y cifras mayores de hemoglobina y Albumina. En el grupo F 5.6 (n = 203), según KDIGO sólo el 33.7 % necesitaría tratamiento. De aplicarse el IndCalDial (fósforo menor a 5 mg/dL), el porcentaje sería de 55%, es decir, un 21.3% de pacientes normofosfatémicos deberían ser tratados. Conclusiones: Debería estandarizarse la determinación de fosfatemia, previo a utilizar un valor fijo como IndCalDial.

Introduction: Bone and mineral metabolism disorder is a serious complication of Chronic Kidney Disease. Concerning phosphorus, the new KDIGO Guidelines suggest a reduction of hyperphosphatemia, but they do not recommend a specific value. However, in Argentina, a phosphorus value of 5 mg/dL or less is used as a dialysis quality indicator (DiaQualInd). Our objective was to evaluate whether this goal is currently valid as a DiaQualInd. Methods: A multicentric, cross-sectional study was conducted. Patients older than 18 were included, with more than 90 days undergoing hemodialysis. Demographic and laboratory data were tabulated, comparing normophosphatemic with hyperphosphatemic values. According to this method, in 3 centers the upper reference limit was 4.5 mg/dL and in 4 centers it was 5.6 mg/dL. The latter were analyzed as a separate group (F 5.6). Results: There were 333 patients included in this study. Age, sex, AVF percentage, diabetes, time on dialysis, Kt/V, hemoglobin and albumin were similar to the registry data. The median phosphatemia was 5.2 mg/dL, (range: 2.3 to 10.6). The hyperphosphatemic patients were the youngest, spent less time on dialysis and showed higher hemoglobin and albumin values. In group F 5.6 (n = 203), according to KDIGO only 33.7% would need treatment. If this DiaQualInd were to be applied (phosphorus lower than 5 mg/dL), the percentage would be 55%, that is, 21.3% of normophosphatemic patients should be treated. Conclusions: Phosphatemia determination should be standardized before using a fixed value such as DiaQualInd

Difference between true functional haemoglobin and pre-dialysis haemoglobin is associated with plasma volume variation: a multicentre study.

PURPOSE: Due to the well-known intradialytic haemoglobin (Hb) change, it has been suggested that true functional Hb differs from pre-dialysis Hb. However, mechanisms of this change are not understood properly. We aimed at studying the role of plasma volume variation. METHODS: This is a multicentre study with two consecutive phases. First, true functional Hb was predicted by Krisper's formula that estimates time-averaged haemoglobin concentration (TAC-Hb) and by the average (Avg-Hb) of Pre-Hb and Post-Hb (n = 346). Erythropoiesis-stimulating agent (ESA) doses were estimated according to the FDA instructions. Second, we investigated the correlations between Hb changes (ΔHb), body weight loss (ΔBW) and relative plasma volume changes (%ΔPV) in subjects with a weight gain higher than 1 kg (n = 208). RESULTS: First: Avg-Hb and TAC-Hb were similar to each other and higher than midweek Pre-Hb (p < 0. 002). Odds of having an Hb change >1 g/dL were 0.415. Odds were similar in both women and men [odds ratio (OR) 0.923; 95 % confidence interval (CI) 0.591-1.441]. If ESA doses were estimated by TAC-Hb or Avg-Hb instead of Pre-Hb, they should be lower in 40 % of the 346 patients. Second: Mean %ΔPV was -12.1 % (95 % CI -10.72/-13.48), and mean ΔHb was 1.1 g/dL (95 % CI 0.97/1.25). Correlation between ΔHb and %ΔPV was -0.92 (r (2) 0.84) whereas that of ΔHb/ΔBW was just -0.45 (r (2) 0.21; p < 0.000). Prevalence of ΔHb >1 g/dL was independent of ΔBW from 1.4 to 6.3 kg. By contrast, prevalence of ΔHb >1 g/dL in %ΔPV quartiles was clearly linear: 0, 52, 90 and 100 %, respectively. CONCLUSIONS: Plasma volume variations play a major role in intradialytic Hb change. True functional Hb should be estimated in all patients with a weight gain higher than 1 kg.

[Optimizing iron therapy in hemodialysis: a prospective long term clinical study]. / Optimizacion del tratamiento con hierro endovenoso en hemodialisis. Estudio clínico prospectivo a largo plazo.

The usefulness of intravenous iron therapy in hemodialysis is evidence-based. However, controversy still arises about the most suitable iron marker to optimize this treatment in the long term. We aimed to determine the most suitable marker with a prospective, cohort study, designed to comprise a basal period (BP) and two consecutive experimental periods (PI, PII). Low molecular weight iron dextran was infused at 100, 150 and 200 mg/month respectively, on a biweekly basis, during 6 months. At the end of each period, the following were determined: transferrin saturation (TSAT), ferritin (FERR), percentage of hypochromic eritrocytes (HYPO) and haemoglobin content in reticulocytes (HCr). During the study, albumin increased significantly, whereas no significant changes in hemoglobin, EPO doses and C-reactive protein were observed. Changes in HYPO and FERR were unspecific. Only TSAT (from 21.4 ± 6 in PB to 34 ± 7.1% in PII, p < 0.01) and HCr (from 27.5 ± 1.3 in PB to 29.3 ± 1.7 pg in PII, P < 0.05 ) responded specifically to changes in Fe doses, but change of TSAT was 65% (CI 95% 22), whereas change of HCr was just 6% (CI 95% 2.3; p = 0.0002). The difference was observed in all patients. Results suggest that 200 mg/FeIV/month is effective and that, of the markers tested in this study, TSAT would be the most suitable one to the practicing nephrologist to optimize intravenous iron in the long term.

Optimización del tratamiento con hierro endovenoso en hemodiálisis: Estudio clínico prospectivo a largo plazo / Optimizing iron therapy in hemodialysis: a prospective long term clinical study

A pesar del amplio uso del hierro endovenoso en hemodiálisis, resta aún identificar un índice adecuado para optimizar esta terapéutica en el largo plazo. Con ese objetivo, se diseñó un estudio prospectivo de cohorte, de larga duración, que consistió en un período basal (PB) y dos períodos experimentales: PI y PII. Se infundió hierro dextran de bajo peso molecular a 100, 150 y 200 mg/mes, respectivamente, durante 6 meses y al final de cada periodo se determinaron: saturación de transferrina (TSAT), ferritina (FERR), porcentaje de eritrocitos hipocrómicos (HYPO) y contenido de hemoglobina en reticulocitos (HCr). Durante el estudio la albúmina aumentó significativamente, pero la Hgb, la dosis de EPO y la proteína C-reactiva se mantuvieron sin cambios. Los cambios en HYPO y FERR fueron inespecíficos. Sólo TSAT (desde 21.4 ± 6 en PB a 34 ± 7.1% en PII, p = 0.01) y HCr (desde 27.5 ± 1.3 en PB a 29.3 ± 1.7 pg en PII, P = 0.045) respondieron específicamente, pero el porcentaje de aumento de TSAT fue de 65% (IC95% 22), y el de HCr sólo 6% (IC95% 2.3; p = 0.0002). Esta diferencia a favor de TSAT se observó en todos los pacientes. Los resultados sugieren la utilización de 200 mg/FeIV/mes y que, de los índices estudiados, TSAT sería el más adecuado para optimizar el uso a largo plazo del hierro endovenoso en hemodiálisis.

The usefulness of intravenous iron therapy in hemodialysis is evidence-based. However, controversy still arises about the most suitable iron marker to optimize this treatment in the long term. We aimed to determine the most suitable marker with a prospective, cohort study, designed to comprise a basal period (BP) and two consecutive experimental periods (PI, PII). Low molecular weight iron dextran was infused at 100, 150 and 200 mg/month respectively, on a biweekly basis, during 6 months. At the end of each period, the following were determined: transferrin saturation (TSAT), ferritin (FERR), percentage of hypochromic eritrocytes (HYPO) and haemoglobin content in reticulocytes (HCr). During the study, albumin increased significantly, whereas no significant changes in hemoglobin, EPO doses and C-reactive protein were observed. Changes in HYPO and FERR were unspecific. Only TSAT (from 21.4 ± 6 in PB to 34 ± 7.1% in PII, p < 0.01) and HCr (from 27.5 ± 1.3 in PB to 29.3 ± 1.7 pg in PII, P < 0.05 ) responded specifically to changes in Fe doses, but change of TSAT was 65% (CI 95% 22), whereas change of HCr was just 6% (CI 95% 2.3; p = 0.0002). The difference was observed in all patients. Results suggest that 200 mg/FeIV/month is effective and that, of the markers tested in this study, TSAT would be the most suitable one to the practicing nephrologist to optimize intravenous iron in the long term.