Dual outflow upper arm arteriovenous fistula: An effective technique to prevent cephalic arch stenosis.

Cephalic arch stenosis (CAS) is critical point to maintain functional arteriovenous fistula (AVF) in patients undergoing hemodialysis with brachio-cephalic AVFs. In this study, we aimed to determine the effectiveness of dual outflow (cephalic and basilic veins) as a surgical method to prevent CAS. Between July 2016 and December 2019, 369 patients underwent upper arm AVF creation. Among them the 251 patients were enrolled in this retrospective study. Two hundred seven underwent brachio-cephalic arteriovenous fistula (BCAVF) and 44 underwent brachio-cephalicbasilic arteriovenous fistula (BCBAVF). From the 251 patients, diabetes mellitus (66.7% vs 36.4%, P < .001) and hypertension (91.3% vs 75%, P = .002) were more common in the patient group who underwent BCAVF surgery; however, the difference in volume flow to the fistula did not differ between the 2 groups. CAS (30.4% vs 9.1%, P = .004) and fistula occlusion (15.9% vs 4.5%, P = .048) were likely to occur in the BCAVF group. The primary patency rates at 12 months were 74.3% and 86.4% for the BCAVFs and BCBAVFs, respectively (P = .075). The primary-assisted patency rates at 12 months were 87.0% for BCAVFs and 93.2% for BCBAVFs, respectively (P = .145). Secondary patency rates at 12 months were 92.2% for BCAVFs and 93.2% for BCBAVFs, respectively (P = .023). Compared to BCAVF, traditional upper arm AVF, upper arm AVF with cephalic and basilic vein dual drainage can be optimal surgical method to preventing CAS.

Tailoring of arteriovenous graft-to-vein anastomosis angle to attenuate pathological flow fields.

Arteriovenous grafts are routinely placed to facilitate hemodialysis in patients with end stage renal disease. These grafts are conduits between higher pressure arteries and lower pressure veins. The connection on the vein end of the graft, known as the graft-to-vein anastomosis, fails frequently and chronically due to high rates of stenosis and thrombosis. These failures are widely believed to be associated with pathologically high and low flow shear strain rates at the graft-to-vein anastomosis. We hypothesized that consistent with pipe flow dynamics and prior work exploring vein-to-artery anastomosis angles in arteriovenous fistulas, altering the graft-to-vein anastomosis angle can reduce the incidence of pathological shear rate fields. We tested this via computational fluid dynamic simulations of idealized arteriovenous grafts, using the Bird-Carreau constitutive law for blood. We observed that low graft-to-vein anastomosis angles ([Formula: see text]) led to increased incidence of pathologically low shear rates, and that high graft-to-vein anastomosis angles ([Formula: see text]) led to increased incidence of pathologically high shear rates. Optimizations predicted that an intermediate  ([Formula: see text]) graft-to-anastomosis angle was optimal. Our study demonstrates that graft-to-vein anastomosis angles can significantly impact pathological flow fields, and can be optimized to substantially improve arteriovenous graft patency rates.

How to Reduce the Risk of Arteriovenous Fistula Dysfunction by Observing Prepump Arterial Pressure during Hemodialysis: A Multicenter Retrospective Study.

OBJECTIVE: Prepump arterial (Pa) pressure indicates the ease or difficulty with which the blood pump can draw blood from the vascular access (VA) during hemodialysis. Some studies have suggested that the absolute value of the Pa pressure to the extracorporeal blood pump flow (Qb) ratio set on the machine (|Pa/Qb|) can reflect the dysfunction of VA. This study was conducted to explore the impact of arteriovenous fistula (AVF) dysfunction and to explore the clinical reference value of |Pa/Qb|. METHODS: We retrospectively identified adults who underwent hemodialysis at 3 hospitals. Data were acquired from electronic health records. We evaluated the pattern of the association between |Pa/Qb| and AVF dysfunction during 1 year using a Cox proportional hazards regression model with restricted cubic splines. Then, the patients were grouped based on the results, and hazard ratios were compared for different intervals of |Pa/Qb|. RESULTS: A total of 490 patients were analyzed, with an average age of 55 (44, 66) years. There were a total of 85 cases of AVF dysfunction, of which 50 cases were stenosis and 35 cases were thrombosis. There was a U-shaped association between |Pa/Qb| and the risk of AVF dysfunction (p for nonlinearity <0.001). |Pa/Qb| values <0.30 and >0.52 increased the risk of AVF dysfunction. Compared with the group with a |Pa/Qb| value between 0.30 and 0.52, the groups with |Pa/Qb| <0.30 and |Pa/Qb| >0.52 had a 4.04-fold (p = 0.002) and 3.41-fold (p < 0.001) greater risk of AVF dysfunction, respectively. CONCLUSIONS: The appropriate range of |Pa/Qb| is between 0.30 and 0.52. When |Pa/Qb| is <0.30 or >0.52, the patient's AVF function or Qb setting should be reevaluated to prevent subsequent failure.

Rationale and Trial Design of MesEnchymal Stem Cell Trial in Preventing Venous Stenosis of Hemodialysis Vascular Access Arteriovenous Fistula (MEST AVF Trial).

Background: Hemodialysis arteriovenous fistulas (AVFs) are the preferred vascular access for patients on hemodialysis. In the Hemodialysis Fistula Maturation Study, 44% of the patients achieved unassisted maturation of their fistula without needing an intervention. Venous neointimal hyperplasia (VNH) and subsequent venous stenosis are responsible for lack of maturation. There are no therapies that can prevent VNH/VS formation. The goal of this paper is to present the background, rationale, and trial design of an innovative phase 1/2 clinical study that is investigating the safety of autologous adipose-derived mesenchymal stem cells delivered locally to the adventitia of newly created upper extremity radiocephalic (RCF) or brachiocephalic fistula (BCF). Methods: The rationale and preclinical studies used to obtain a physician-sponsored investigational new drug trial are discussed. The trial design and end points are discussed. Results: This is an ongoing trial that will complete this year. Conclusion: This is a phase 1/2 single-center, randomized trial that will investigate the safety and efficacy of autologous AMSCs in promoting maturation in new upper-extremity AVFs.Clinical Trial registration number: NCT02808208.

Formación en una estrategia multimodal sobre el cuidado de los catéteres venosos periféricos: impacto en la preservación del árbol vascular de pacientes de una unidad de nefrología / Training in a multimodal strategy on the care of peripheral venous catheters: impact on the preservation of the patient's vascular tree in a nephrology unit

Introducción: Un desarrollo adecuado de las fístulas arteriovenosas está relacionado con el estado del árbol vascular y el uso previo de dispositivos de acceso venoso periférico (CVP). Objetivo: Evaluar el impacto de la formación en una estrategia multimodal para reducir las complicaciones relacionadas con el CVP en una unidad de hospitalización de nefrología. Material y Método: Estudio cuasi-experimental pre-post intervención, en pacientes portadores de CVP en una unidad de hospitalización de nefrología. La intervención consistió en la formación en una estrategia multimodal para el manejo de CVP basada en 5 medidas basadas en evidencia. Para determinar el impacto se analizaron los registros electrónicos de los CVP insertados en los 3 meses previos a la actividad formativa (PRE) vs 3 meses posteriores (POST). Se realizó un análisis descriptivo e inferencial de las variables a estudio. Resultados: CVP estudiados: PRE n=96, POST n=120. Número medio de CVP/paciente: PRE 2,07 vs POST 1,75 (p=0,02). Calibre: PRE 18G 1%, 20G 18%, 22G 80%, 24G 1%; POST 20G 20%, 22G 80% (p=NS). Duración media: PRE 192h, <7 días 26% vs POST 171h, <7 días 30% (p=NS). Causas de retirada: Alta / no precisa PRE 41% vs POST 38% (p=NS), Flebitis PRE 27% vs POST 13% (p=NS). Conclusiones: la formación en una estrategia multimodal ha conseguido reducir: número de CVP por paciente, número de flebitis, uso de CVP de mayor calibre y tiempo que permanecen insertados. Una estrategia multimodal sobre el manejo de los CVP puede ayudar a preservar el árbol vascular en pacientes nefrológicos

Introduction: An adequate development of arteriovenous fistulas is related to the state of the vasculature and the previous use of peripheral venous catheter (PVC). Objective: To evaluate the impact of training in a multimodal strategy to reduce complications related to PVC in a nephrology hospitalization unit. Material and Method: Quasi-experimental pre-post intervention study in patients with PVC in a nephrology hospitalization unit. The intervention was training in a multimodal strategy for PVC management based on 5 evidence-based measures. To determine the impact, the electronic medical records of the PVCs inserted in the 3 months prior to the training activity (PRE) versus 3 months later (POST) were analyzed. A descriptive and inferential analysis of the variables to be studied was performed. Results: PVC studied: PRE n=96, POST n=120. Average number of PVC/patient: PRE 2.07 vs. POST 1.75 (p=0.02). Caliber: PRE 18G 1%, 20G 18%, 22G 80%, 24G 1%; POST 20G 20%, 22G 80% (p=NS). Average duration: PRE 192h, <7 days 26% vs POST 171h, <7 days 30% (p = NS). Withdrawal causes: High/not accurate PRE 41% vs POST 38% (p=NS), Phlebitis PRE 27% vs POST 13% (p=NS). Conclusions: Training in a multimodal strategy has managed to reduce: number of PVC per patient, number of phlebitis, use of PVC of greater caliber and time that remain inserted. A multimodal strategy on the PVCs management can help preserve the vascular tree in nephrological patients

Vascular access in children requiring maintenance haemodialysis: a consensus document by the European Society for Paediatric Nephrology Dialysis Working Group

There are three principle forms of vascular access available for the treatment of children with end stage kidney disease (ESKD) by haemodialysis: tunnelled catheters placed in a central vein (central venous lines, CVLs), arteriovenous fistulas (AVF), and arteriovenous grafts (AVG) using prosthetic orbiological material. Compared with the adult literature, there are few studies in children to provide evidence based guidelines for optimal vascular access type or its management and outcomes in children with ESKD.

Fatores de risco para pacientes com falência recorrente de fístula arteriovenosa / Risk factors for patients showing arteriovenous fistula recurrent failure / Factores de riesgo para pacientes con falencia recorrente de fiesta arteriovenosa

Objetivo: Identificar os fatores de risco/condicionantes para a falência da fístula arteriovenosa e analisar os cuidados necessários para manutenção da fístula arteriovenosa. Métodos: Estudo piloto realizado com 10 participantes com histórico de falência de fístula arteriovenosa, com dados coletados por meio de formulário e analisados por estatística descritiva, aceito pelo Comitê de Ética em Pesquisa do Hospital Universitário Pedro Ernesto, com número do CAAE nº 64150117.2.0000.5259. Resultados: A idade média foi de 57,3 anos. A hipertensão arterial foi a doença prévia mais comum encontrada entre os participantes. A hipotensão e as punções repetidas foram os fatores de risco/condicionantes com maior ocorrência. Conclusão: a maioria dos participantes possuíam baixa escolaridade e informaram ter tido alguma complicação na FAV. A hipotensão como fator condicionante para falência das FAV, permaneceu de forma frequente entre os participantes. Observou-se que grande parte já realizava tratamento dialítico prévio

Objective: The study's purpose has been to identify the risk/conditioning factors for Arteriovenous Fistula Failure (AVF), and also to analyze the care required for handling the arteriovenous fistula. Methods: It is a pilot study that was carried out with 10 participants showing a history of AVF. The data were collected through a form and analyzed by descriptive statistics. This research was accepted by the Research Ethics Committee from the Pedro Ernesto University Hospital, under the Certificado de Apresentação para Apreciação Ética (CAAE) [Certificate of Presentation for Ethical Appreciation] No. 64150117.2.0000.5259. Results: The average age was 57.3 years old. Arterial hypertension was the most common prior disease among the participants. Hypotension and repeated punctures were the most frequent risk/conditioning factors. Conclusion: A relevant percentage of the participants had little education and reported having had some complication in the AVF. Hypotension, as a conditioning factor for AVF failure, remained frequent among the participants. It was observed that a large part of the participants have undergone dialysis treatment previously

Objetivo: Identificar los factores de riesgo / condicionantes para la quiebra de la fístula arteriovenosa y analizar los cuidados necesarios para el mantenimiento de la fístula arteriovenosa. Métodos: Estudio piloto realizado con 10 participantes con historial de fallo de fístula arteriovenosa, con datos recogidos por medio de formulario y analizados por estadística descriptiva, aceptado por el Comité de Ética en Investigación del Hospital Universitario Pedro Ernesto, con número del CAAE nº 64150117.2.0000.5259 . Resultados: La edad media fue de 57,3 años. La hipertensión arterial fue la enfermedad previa más común entre los participantes. La hipotensión y las punciones repetidas fueron los factores de riesgo / condicionantes con mayor ocurrencia. Conclusión: la mayoría de los participantes tenían baja escolaridad e informaron haber tenido alguna complicación en la FAV. La hipotensión como factor condicionante para la quiebra de las FAV, permaneció de forma frecuente entre los participantes. Se observó que gran parte ya realizaba tratamiento dialítico previo

Three years' experience of dialysis event surveillance.

BACKGROUND: The main study aim was to track infections, evaluate performance, and identify opportunities for improved practice since infections, especially those associated with multidrug-resistant organisms, are the second most common cause of death among end-stage renal disease patients. METHODS: This study describes the establishment of baseline dialysis event surveillance at a large dialysis center. Every month, the dialysis center staff reported the total number of maintenance hemodialysis patients to the department of infection control and hospital epidemiology. The surveillance system for dialysis events included monthly monitoring of hemodialysis patients in outpatient settings for positive blood cultures, intravenous antimicrobial initiation, and local vascular access infections. RESULTS: We calculated the pooled mean rates of positive blood cultures, intravenous antimicrobial initiation, and local vascular access infections during the period from June 1, 2014 to September 30, 2017. Results indicated more dialysis events were attributed to the CVC than any other dialysis vascular access. Regardless of vascular access type, intravenous antimicrobial initiation was the most commonly reported dialysis-associated event. CONCLUSIONS: Dialysis events surveillance can be used to produce a decrease in both morbidity and mortality rates in hemodialysis patients.

Consulta de acceso vascular: resultados antes y después de la instauración de un programa multidisciplinar con realización de ecografía doppler de rutina / Vascular access clinic results before and after implementing a multidisciplinary approach adding routine Doppler ultrasound

ANTECEDENTES Y OBJETIVO: El abordaje multidisciplinar y el uso de ecografía doppler (ED) en la creación y vigilancia del acceso vascular (AV) puede mejorar la prevalencia y permeabilidad de las fístulas arteriovenosas (FAV) para hemodiálisis. El objetivo de este estudio es analizar el impacto de una nueva consulta multidisciplinar (CMD) de AV con ED de rutina. MATERIAL Y MÉTODOS: Evaluamos los resultados de la consulta de AV en 2014 (pre-CMD) y 2015 (CMD), antes y después de la implantación de un equipo multidisciplinar (cirujano vascular/nefrólogo) con ED de rutina en mapeo prequirúrgico y FAV prevalente. RESULTADOS: Se evaluaron 345 pacientes en 2014 (pre-CMD) y 364 pacientes en 2015 (CMD). En ambos periodos se realizó un número similar de cirugías, 172 vs. 198, p = 0,289, con tendencia a aumentar las cirugías preventivas de reparación de FAV en el periodo CMD, 17 vs. 29 (p = 0,098). En FAV de nueva creación (155 vs. 169), disminuyó la tasa de fallo primario en el periodo CMD, 26,4 vs. 15,3%, p = 0,015 y aumentó de forma no significativa la realización de FAV radiocefálicas distales, 25,8 vs. 33,2% (n = 40 vs. 56), p = 0,159. También aumentó la concordancia entre la indicación quirúrgica en la consulta y la cirugía realizada (81,3 vs. 93,5%, p = 0,001). En el periodo CMD se solicitaron menos exploraciones radiológicas desde la consulta, 78 vs. 35 (p < 0,001), con una reducción del gasto sanitario (81.716€ vs. 59.445€). CONCLUSIONES: El manejo multidisciplinar y la utilización del ED de rutina permiten mejorar los resultados de AV, con disminución de la tasa de fallo primario de FAV, más opciones de FAV distal nativa, mejor manejo de la FAV prevalente disfuncionante y menor coste en exploraciones radiológicas

BACKGROUND: A multidisciplinary approach and Doppler ultrasound (DU) assessment for the creation and maintenance of arteriovenous fistulas (AVF) for haemodialysis can improve prevalence and patency. The aim of this study was to analyse the impact of a new multidisciplinary vascular access (VA) clinic with routine DU. MATERIAL AND METHODS: We analysed the VA clinic results from 2014 and 2015, before and after the implementation of a multidisciplinary team protocol (vascular surgeon/nephrologist) with routine DU in preoperative mapping and prevalent AVF. RESULTS: We analysed 345 and 364 patients from 2014 and 2015 respectively. The number of surgical interventions was similar in both periods (p = .289), with a trend towards an increase in preventive surgical repair of AVF in 2015 (17 vs. 29, p = .098). 155 vs. 169 new AVF were performed in 2014 and 2015, with a significantly lower primary failure rate in 2015 (26.4 vs. 15.3%, p = .015), and a non-significant increase in radiocephalic AVF, 25.8 vs. 33.2% (n = 40 vs. 56), p = .159. The concordance between the indication at the clinic and the surgery performed also increased (81.3 vs. 93.5%, p = .001). Throughout 2015 fewer complementary imaging test were requested from the clinic (78 vs. 35, p < .001), with a corresponding reduction in costs (€87,716 vs. €59,445). CONCLUSIONS: Multidisciplinary approach with routine DU can improve VA results, with a decrease in primary failure rate, higher likelihood of radiocephalic AVF, better management of dis-functioning AVF and lower radiological test costs

CorMatrix Wrapped Around the Adventitia of the Arteriovenous Fistula Outflow Vein Attenuates Venous Neointimal Hyperplasia.

Venous neointimal hyperplasia (VNH) at the outflow vein of hemodialysis AVF is a major factor contributing to failure. CorMatrix is an extracellular matrix that has been used in cardiovascular procedures primarily as scaffolding during surgery. In the present study, we sought to determine whether CorMatrix wrapped around the outflow vein of arteriovenous fistula (AVF) at the time of creation could reduce VNH. In mice, the carotid artery to the ipsilateral jugular vein was connected to create an AVF, and CorMatrix scaffold was wrapped around the outflow vein compared to control mice that received no scaffolding. Immunohistochemistry, Western blot, and qRT-PCR were performed on the outflow vein at 7 and 21 days after AVF creation. In outflow veins treated with CorMatrix, there was an increase in the mean lumen vessel area with a decrease in the ratio of neointima area/media + adventitia area (P < 0.05). Furthermore, there was a significant increase in apoptosis, with a reduction in cell density and proliferation in the outflow veins treated with CorMatrix compared to controls (P < 0.05). Immunohistochemical analysis revealed a significant reduction in fibroblasts, myofibroblasts, macrophages, and leukocytes with a reduction in Tnf-α gene expression (P < 0.05). In conclusion, outflow veins treated with CorMatrix have reduced VNH.

Guía Clínica Española del Acceso Vascular para Hemodiálisis / Spanish Clinical Guidelines on Vascular Access for Haemodialysis

El acceso vascular para hemodiálisis es esencial para el enfermo renal tanto por su morbimortalidad asociada como por su repercusión en la calidad de vida. El proceso que va desde la creación y mantenimiento del acceso vascular hasta el tratamiento de sus complicaciones constituye un reto para la toma de decisiones debido a la complejidad de la patología existente y a la diversidad de especialidades involucradas. Con el fin de conseguir un abordaje consensuado, el Grupo Español Multidisciplinar del Acceso Vascular (GEMAV), que incluye expertos de las cinco sociedades científicas implicadas (nefrología [S.E.N.], cirugía vascular [SEACV], radiología vascular e intervencionista [SERAM-SERVEI], enfermedades infecciosas [SEIMC] y enfermería nefrológica [SEDEN]), con el soporte metodológico del Centro Cochrane Iberoamericano, ha realizado una actualización de la Guía del Acceso Vascular para Hemodiálisis publicada en 2005. Esta guía mantiene una estructura similar, revisando la evidencia sin renunciar a la vertiente docente, pero se aportan como novedades, por un lado, la metodología en su elaboración, siguiendo las directrices del sistema GRADE con el objetivo de traducir esta revisión sistemática de la evidencia en recomendaciones que faciliten la toma de decisiones en la práctica clínica habitual y, por otro, el establecimiento de indicadores de calidad que permitan monitorizar la calidad asistencial (AU)

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare (AU)

Fistula First Initiative: Historical Impact on Vascular Access Practice Patterns and Influence on Future Vascular Access Care.

The vascular access is the lifeline for the hemodialysis patient. In the United States, the Fistula First Breakthrough Initiative (FFBI) has been influential in improving use of arteriovenous fistulas (AVF) in prevalent hemodialysis patients. Currently, prevalent AVF rates are near the goal of 66% set forth by the original FFBI. However, central venous catheter (CVC) rates remain very high in the United States in patients initiating hemodialysis, nearly exceeding 80%. A new direction of the of the FFBI has focused on strategies to reduce CVC use, and subsequently the FFBI has now been renamed the "Fistula First-Catheter Last Initiative". However, an AVF may not be the best vascular access in all hemodialysis patients, and arteriovenous grafts (AVG) and CVCs may be appropriate and the best access for a subset of hemodialysis patients. Unfortunately, there still remains very little emphasis within vascular access initiatives and guidelines directed towards evaluation of the individual patient context, specifically patients with poor long-term prognoses and short life expectancies, patients with multiple comorbidities, patients who are more likely to die than reach end stage renal disease (ESRD), and patients of elderly age with impaired physical and cognitive function. Given the complexity of medical and social issues in advanced CKD and ESRD patients, planning, selection, and placement of the most appropriate vascular access are ideally managed within a multidisciplinary setting and requires consideration of several factors including national vascular access guidelines. Thus, the evolution of the FFBI should underscore the need for multidisciplinary health teams with a major emphasis placed on "the right access for the right patient" and improving the patient's overall quality of life.

Angiotensin Converting-Enzyme Inhibitors, Angiotensin Receptor Blockers, and Calcium Channel Blockers Are Associated with Prolonged Vascular Access Patency in Uremic Patients Undergoing Hemodialysis.

BACKGROUND: Vascular access failure is a huge burden for patients undergoing hemodialysis. Many efforts have been made to maintain vascular access patency, including pharmacotherapy. Angiotensin converting enzyme inhibitor (ACE-I), angiotensin receptor blocker (ARB), and calcium channel blocker (CCB) are known for their antihypertensive and cardio-protective effects, however, their effects on long-term vascular access patency are still inconclusive. DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS: We retrospectively enrolled patients commencing maintenance hemodialysis between January 1, 2000, and December 31, 2006 by using National Health Insurance Research Database in Taiwan. Primary patency was defined as the date of first arteriovenous fistula (AVF) or arteriovenous graft (AVG) creation to the time of access thrombosis or any intervention aimed to maintain or re-establish vascular access patency. Cox proportional hazards models were used to adjust the influences of patient characteristics, co-morbidities and medications. RESULTS: Total 42244 patients were enrolled in this study, 37771 (89.4%) used AVF, 4473 (10.6%) used AVG as their first long term dialysis access. ACE-I, ARB, and CCB use were all associated with prolonged primary patency of AVF [hazard ratio (HR) 0.586, 95% confidence interval (CI) 0.557-0.616 for ACE-I use; HR 0.532, CI 0.508-0.556 for ARB use; HR 0.485, CI 0.470-0.501 for CCB use] and AVG (HR 0.557, CI 0.482-0.643 for ACE-I use, HR 0.536, CI 0.467-0.614 for ARB use, HR 0.482, CI 0.442-0.526 for CCB use). CONCLUSIONS: In our analysis, ACE-I, ARB, and CCB were strongly associated with prolonged primary patency of both AVF and AVG. Further prospective randomized studies are still warranted to prove the causality.

Impacto del calibre de las agujas en la calidad de la hemodiálisis / Impact of the needle gauge in the quality of hemodialysis

Introducción: El flujo de sangre es uno de los factores íntimamente relacionado con la eficacia de la diálisis. Flujos altos de sangre se asocia a mejor calidad de diálisis y para ello, se recomienda el uso de agujas de gran calibre. Objetivo: Analizar el efecto del calibre de las agujas utilizadas en la punción de las fístulas arteriovenosas, así como, examinar su impacto en la percepción del dolor y en el tiempo de coagulación tras su retirada al finalizar la sesión. Material y método: Se ha llevado a cabo un estudio transversal. Se han recogido datos utilizando para la punción de la fístula arteriovenosa agujas de calibre 15G y 16G. Las variables recogidas han sido velocidad de bomba, flujo efectivo, Kt/V, presión venosa, duración de la sesión, tensión arterial sistólica, tensión arterial diastólica, recirculación, grado de dolor y tiempo de coagulación. Además, se han recogido las variables edad, sexo y localización del acceso vascular. Resultados: En 52 fístulas analizadas se ha encontrado diferencias estadísticamente significativas en el uso de los distintos calibres de aguja en las variables flujo de sangre efectivo, presión venosa y duración de la sesión. Discusión: Los resultados de nuestro estudio nos permiten recomendar el uso de aguja 15G ya que nos permitirán utilizar altos flujos de sangre sin generar morbilidad para el paciente, permitiendo alcanzar la dosis de diálisis recomendada en menos tiempo de tratamiento (AU)

Introduction: Blood flow is a factor closely related to the dialysis efficacy. High blood flows are associated with better quality of dialysis and therefore the use of large needle gauge is recommended. Objective: Analyze the effect of gauge needles in the puncture of arteriovenous fistulas and examine its impact on the perception of pain and bleeding time after his retirement at the end of the session. Methods: A cross-sectional study was conducted. Data were collected using 15G and 16G needles to puncture the arteriovenous fistula. The variables are pump speed, effective flow, Kt/V, venous pressure, session length, systolic blood pressure, diastolic blood pressure, recirculation, degree of pain and clotting time. In addition, we have collected the variables age, sex and location of the vascular access. Results: In 52 analyzed fistulas found statistically significant differences in the use of different needle gauges in the variables effective blood flow, venous pressure and duration of the session. Discussion: The results of our study allow us to recommend the use of 15G needles because they will allow us to use high blood flows without generating morbidity for the patient, allowing reaching the recommended dose of dialysis treatment in less time (AU)

An overview of permanent vascular access in hemodialyzed patients.

In the last decade, because of significant number of end-stage renal disease individuals in need of renal therapy replacement and permanent quest of nephrologist to optimize kidney disease patients' quality of life, there is an increased interest in achieving a suitable permanent vascular access, essential for an efficient dialysis. Furthermore, it is of high importance to preserve arteriovenous fistula in optimal condition and therefore, it is vital to correctly understand the histopathology and pathophysiological mechanisms implicated in maturation and well function of dialysis vascular access.

Improving arteriovenous fistula patency: Transdermal delivery of diclofenac reduces cannulation-dependent neointimal hyperplasia via AMPK activation.

Creation of an autologous arteriovenous fistula (AVF) for vascular access in haemodialysis is the modality of choice. However neointimal hyperplasia and loss of the luminal compartment result in AVF patency rates of ~60% at 12months. The exact cause of neointimal hyperplasia in the AVF is poorly understood. Vascular trauma has long been associated with hyperplasia. With this in mind in our rabbit model of AVF we simulated cannulation autologous to that undertaken in vascular access procedures and observed significant neointimal hyperplasia as a direct consequence of cannulation. The neointimal hyperplasia was completely inhibited by topical transdermal delivery of the non-steroidal anti-inflammatory (NSAID) diclofenac. In addition to the well documented anti-inflammatory properties we have identified novel anti-proliferative mechanisms demonstrating diclofenac increases AMPK-dependent signalling and reduced expression of the cell cycle protein cyclin D1. In summary prophylactic transdermal delivery of diclofenac to the sight of AVF cannulation prevents adverse neointimal hyperplasic remodelling and potentially offers a novel treatment option that may help prolong AVF patency and flow rates.

Pacientes em hemodiálise com fístula arteriovenosa: conhecimento, atitude e prática / Hemodialysis patients with arteriovenous fistula: knowledge, attitude and practice

Objetivo: Identificar o conhecimento, atitude e prática dos pacientes em hemodiálise sobre autocuidado com fístula arteriovenosa. Métodos: Estudo descritivo, corte transversal e abordagem quantitativa. Envolveu 30 pacientes que realizavam hemodiálise por meio de fístula arteriovenosa no Hospital Barão de Lucena. Resultados: 97,7% dos pacientes apresentaram conhecimento inadequado. A atitude foi adequada em 70% dos pesquisados. A prática de autocuidado com a fístula foi inadequada em 97,7% dos pacientes. Conclusão: Apesar da maioria dos pacientes apresentarem uma atitude adequada em relação aos cuidados com a fístula, seu conhecimento e prática foram inadequados. O conhecimento inadequado, provavelmente, influenciou em uma prática inapropriada. O uso do material escrito pode ser recomendado como um instrumento facilitador para estratégias educativas posteriores, já que também permite uma leitura posterior pelo usuário, possibilitando-lhe a superação de eventuais dúvidas. .

Fístula arteriovenosa vertebral. Diagnóstico por auscultación / A vertebral arteriovenous fistula diagnosed by auscultation

Las fístulas arteriovenosas (FAV) vertebrales son lesiones raras. La etiología de las FAV vertebrales puede ser traumática o espontánea. Suelen cursar de forma asintomática o refiriendo «ruidos», o palpándose una vibración en la región cervical. El diagnóstico definitivo serealiza mediante arteriografía, siendo la embolización de la fístula el tratamiento de elección. Comentamos el caso de un varón de 2 años en el que la madre aprecia«como una lavadora en la cabeza». Al explorarle se palpa una vibración y se ausculta un soplo continuo en la región cervical izquierda, siendo el resto normal. Con la sospecha clínica de malformación vascular en la región vertebral se solicita una angio-RNM y una posterior arteriografía que confirma el diagnóstico. Las FAV son raras en la infancia. Es necesario sospecharlas ante la presencia de ruidos, palpación o vibración continua en la región cervical. El diagnóstico precoz puede evitar complicaciones

Cervical artery fistulas are rare arteriovenous malformations. The etiology of the vertebral arteriovenous fistulas (AVF) can be traumatic or spontaneous. They tend to be asymptomatic or palpation or continuous vibration in the cervical region. An arteriography is necessary for a definitive diagnosis. The treatment is complete embolization of the fistula. We present the case of a two year-old male, where the mother described it «like a washing machine in his head». On palpation during the physical examination, there was a continuous vibration, and a continuous murmur in left cervical region. A vascular malformation in vertebral region was clinically suspected, and confirmed with angio-MRI and arteriography AVF are rare in childhood. They should be suspected in the presence of noises, palpation or continuous vibration in the cervical region. Early diagnosis can prevent severe complications in asymptomatic children

Fístula arteriovenosa vertebral. Diagnóstico por auscultación / A vertebral arteriovenous fistula diagnosed by auscultation

Las fístulas arteriovenosas (FAV) vertebrales son lesiones raras. La etiología de las FAV vertebrales puede ser traumática o espontánea. Suelen cursar de forma asintomática o refiriendo «ruidos», o palpándose una vibración en la región cervical. El diagnóstico definitivo se realiza mediante arteriografía, siendo la embolización de la fístula el tratamiento de elección. Comentamos el caso de un varón de 2 años en el que la madre aprecia «como una lavadora en la cabeza». Al explorarle se palpa una vibración y se ausculta un soplo continuo en la región cervical izquierda, siendo el resto normal. Con la sospecha clínica de malformación vascular en la región vertebral se solicita una angio-RNM y una posterior arteriografía que confirma el diagnóstico. Las FAV son raras en la infancia. Es necesario sospecharlas ante la presencia de ruidos, palpación o vibración continua en la región cervical. El diagnóstico precoz puede evitar complicaciones

Cervical artery fistulas are rare arteriovenous malformations. The etiology of the vertebral arteriovenous fistulas (AVF) can be traumatic or spontaneous. They tend to be asymptomatic or palpation or continuous vibration in the cervical region. An arteriography is necessary for a definitive diagnosis. The treatment is complete embolization of the fistula. We present the case of a two year-old male, where the mother described it «like a washing machine in his head». On palpation during the physical examination, there was a continuous vibration, and a continuous murmur in left cervical region. A vascular malformation in vertebral region was clinically suspected, and confirmed with angio-MRI and arteriography. AVF are rare in childhood. They should be suspected in the presence of noises, palpation or continuous vibration in the cervical region. Early diagnosis can prevent severe complications in asymptomatic children

The effect of statin therapy on the formation of arteriovenous fistula stenoses and the rate of reoccurrence of previously treated stenoses.

Statins reduce inflammation in end-stage renal disease patients and improve endothelial function beyond cholesterol lowering. Despite this, statins do not improve the maturation rate, primary patency rate, and the cumulative survival of arteriovenous fistulas (AVFs). It is unknown if statins decrease the number of stenoses developing in AVFs or prolong the intervals between angioplasties needed to treat recurring stenoses. We conducted a retrospective chart review of our 265 active dialysis patients. The statin group was significantly more likely to be diabetic (64% vs. 43.6%) and treated with aspirin (64% vs. 40%) when compared to those not treated with statins (P=0.04 and 0.01). The mean time to first intervention (primary patency) was 16.5 months in statin users and 15.8 months in the nonstatin group (P=0.49) with standard deviations of ± 18.5 and 16.6 months, respectively. Statin use was not associated with a significant decrease in the number of stenoses diagnosed (P=0.28). The mean time between recurrent stenoses' angioplasties was 8.9 months in statin users and 7.3 months in the nonstatin patients (P=0.25). Aspirin users were more likely to have a decreased primary patency (rate ratio=1.65, P=0.03) compared with nonaspirin users. Patients who were prescribed aspirin developed 1.6 (P 0.01) times more stenoses than those not treated with aspirin. We report for the first time that statin therapy does not decrease the number of stenotic lesions developing in the AVF or prolong the interval between procedures required to treat recurrent stenoses.