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.

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.

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.

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.

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. .

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.

Strategies for decreasing vascular complications in diagnostic cardiac catheterization patients.

Vascular complications are the most common type of complication after a cardiac catheterization. These include hematoma, pseudoaneurysm, arteriovenous fistula, peripheral artery occlusion and dissection, and retroperitoneal bleeding. The Pennsylvania Patient Safety Authority reports that nearly half the medical errors that occurred between June 2004 and December 2006 were cardiac catheterization complications, many of which were vascular related. The American College of Cardiology's National Cardiovascular Data Registry benchmark for vascular complications incidence is less than 1% for diagnostic catheterizations and less than 3% for percutaneous coronary intervention. The need to search for strategies to decrease vascular complication in diagnostic cardiac catheterization patients was a priority.

As intervenções de enfermagem mais prevalentes em um serviço de hemodiálise frente às intercorrências com a fístula arteriovenosa durante a sessão de hemodiálise / Assistance of nursing service one more prevalent in front of the complications of hemodialysis with arteriovenous fistula session during hemodialysis

Objetivo - O tratamento predominante para insuficiência renal crônica é a hemodiálise, no qual o acesso vascular mais utilizado é a fístula arteriovenosa (FAV). Este estudo objetivou descrever as intercorrências com a FAV durante a sessão de hemodiálise, identificar as intervenções de enfermagem mais prevalentes, e registrar o resultado esperado após as intervenções. Métodos - Trata-se de um estudo qualitativo, não experimental, transversal, descritivo, realizado em uma clinica de hemodiálise no município de Ribeirão Preto. Participaram do estudo 11 auxiliares de enfermagem, nove técnicos e quatro enfermeiros que responderam um questionário semiestruturado entre dezembro de 2010 e janeiro de 2011. Resultados - Os resultados indicaram as intercorrências hematoma ou extravasamento (44,1%) e FAV colabando (18,2%) como as mais predominantes, as intervenções mais prevalentes foram aplicar gelo no local (24%), drenar o local (16,9%), avaliar e repuncionar se possível (14,1%), e administrar ácido mucopolissacárido-polissulfúrico no local do hematoma ou extravasamento (8,5%), e na FAV colabando descreveram manipular a agulha arterial (8,5%) e reposicionar a agulha que poderia estar aderida na parede do vaso (4,2%), quanto ao resultado esperado obtiveram-se informações possíveis de se inferir a existência de uma assistência de enfermagem humanizada, preocupada com bem-estar do paciente, e não apenas com a FAV. Conclusões - Concluiu-se que uma das intervenções mais prevalentes nesse estudo não é a mais referenciada na literatura. Porém a coerência nas intervenções descritas pelos sujeitos, inferindo assim a existência de protocolos para assistência de enfermagem na instituição, ou ações individuais que poderiam estar influenciando outros profissionais. Estudos posteriores poderão compreender as vertentes que se destacaram na realização deste estudo.

Objective - The predominant treatment for chronic renal failure is hemodialysis, in which the most widely used vascular access is the arteriovenous fistula (AVF). This study describes the events with the AVF during the dialysis session, identify nursing interventions are most prevalent, and record the result expected after the interventions. Methods - This is a qualitative study, non-experimental, cross-sectional descriptive study in a hemodialysis clinic in Ribeirão Preto. Study participants were 11 auxiliary nurses, nine technicians and four nurses who answered a semistructured questionnaire between December 2010 and January 2011. Results - The results showed the hematoma or extravasation complications (44.1%) and AVF collapsing (18.2%) were the most prevalent, the interventions were more prevalent at local apply of ice (24%), local drain (16,9%), assess and repuncture if possible (14,1%) and administer mucopolysaccharide polysulfuric acid at local hematoma or extravasation (8.5%), and AVF described collapsing handle the pressure needle (8,5%) and reposition the needle that could be adhered to the vessel wall (4,2%), and the expected result we obtained information possible to infer the existence of a humanized nursing care, concerned with the welfare of the patient, not just with the AVF. Conclusions - It was concluded that one of the most prevalent interventions in this study is not the most referenced in the literature. But consistency in operations described by the subjects, thus inferring the existence of protocols for nursing care in the institution, or individual actions that could be influencing other professionals. Further studies may include those aspects that stood out in this study.

Closure device or manual compression in patients undergoing percutaneous coronary intervention: a randomized comparison.

AIMS: Although closure devices may be comfortable for patients, the clinical benefits in patients with moderate-to-high risk of bleeding are not yet clear. We compared a closure device with manual compression in moderate- to high-risk bleeding patients undergoing percutaneous coronary intervention (PCI). METHODS AND RESULTS: A randomized study was performed to compare a closure device (Angio-Seal, St. Jude Medical, Inc.) with manual compression in 627 patients treated with aspirin, clopidogrel, a glycoprotein IIb/IIIa inhibitor and heparin during PCI. The primary endpoint was the inhospital combined incidence of: 1) severe hematoma > 5 cm at the puncture site or groin bleeding resulting in prolonged hospital stay, transfusion and/or surgical intervention at the puncture site; 2) arteriovenous fistula formation and/or surgical intervention at the puncture site. A total of 313 patients (49.9%) were randomized to the closure device and 314 patients (50.1%) to manual compression. The combined primary endpoint was 2.6% in the closure device group compared to 4.5% in the manual compression group (p = 0.195). In the predefined subgroup of patients with a history of hypertension, however, the combined primary endpoint (0.8% vs. 7.2%; p = 0.008) was significantly reduced after use of the closure device. CONCLUSION: This trial did not show the superiority of using a closure device over manual compression in patients treated with triple antiplatelet therapy who underwent PCI. The fact that patients with a history of hypertension had a benefit from a closure device merits further investigation.