Prosthetic Arteriovenous Grafts for Hemodialysis

Introduction Prosthetic arteriovenous (AV) grafts are indicated in patients with failed AV fistula (AVF), exhausted superficial veins or unsuitable vessels. Increasing the proportion of prevalent hemodialysis (HD) patients using autogenous AVF should reduce the need for AV grafts and associated morbidity. This paper reviews the current role of prosthetic AV grafts in vascular access for HD. Technical considerations Prior to the insertion of a prosthetic AV graft, a comprehensive review of previous access procedures and full physical examination in addition to vessel mapping is required. Anastomotic technique should take into account the flow diffuser concept, graft geometry and an anastomotic angle of 15° in order to reduce the incidence of intimal hyperplasia. Results Many authors report 1 and 2-yr cumulative graft patency rates of 59–90% and 50–82%, respectively. The major drawbacks with synthetic grafts include: thrombosis, a five-fold increase in infection risk and steal syndrome. The choice between surgical and percutaneous methods of dealing with blocked AV grafts remains controversial, though percutaneous techniques are assuming an increasingly important role. Percutaneous strategies are successful in declotting access in 67–95% of cases. Stenting of stenotic lesions following thrombectomy improves secondary patency rates. Strategies for dealing with AV graft infection include antibiotic prophylaxis, partial, subtotal or total graft excision and the use of biological prosthesis. Conclusions Though more prone to complications than autogenous AVFs, AV grafts offer a short maturation period and are more amenable to thrombectomy by radiological or surgical means. Complex AV grafts may be appropriate in patients with exhausted access sites.

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Evaluation of Gore-Tex Graft Patency in Hemodialysis Access

The Journal of Vascular Access ◽

10.1177/112972980300400203 ◽

2003 ◽

Vol 4 (2) ◽

pp. 45-49 ◽

Cited By ~ 1

Author(s):

A. Kawecka ◽

A. DȨbska-Ślizien ◽

G. Korejwo ◽

J. Prajs ◽

E. Król ◽

...

Keyword(s):

Retrospective Study ◽

Graft Patency ◽

Upper Extremities ◽

Study Group ◽

Secondary Patency ◽

Hemodialysis Access ◽

Survival Curves ◽

Rank Analysis ◽

Kaplan Meier ◽

Steal Syndrome

Aim The purpose of this retrospective study was to analyze the patency and complications of Gore-Tex grafts used in hemodialysis (HD) access. Methods In the last 16 years, 1649 surgical procedures were performed on 655 patients to ensure and maintain permanent HD access. The study group consisted of 64 HD patients on whom 81 vascular synthetic PTFE Goretex grafts were performed. There were 28 males and 36 females, 3 of them were children (4.7%). Mean age was 54.2 years (range 15–77). Two types of Gore-Tex prosthesis were used: Diastat and Stretch. All grafts were implanted in the upper extremities. Kaplan-Meier survival curves were calculated to determine primary and secondary patency. Log-rank analysis was used to determine differences between curves. Results Primary and secondary patency at 12 months was 52.5% and 67.5%, and at 18 months respectively 41.5% and 58.2%. The Diastat graft had a lower primary and secondary patency compared with the Stretch graft (respectively p = 0.02 and p = 0.008). Factors such as gender, coexisting diabetes and hypertension did not determine graft patency. Thrombosis was one of the most frequent complications. The remaining complications included stenosis, pseudoaneurysms, infection, steal syndrome and seroma. Conclusion On the basis of our experience Stretch grafts appear a better option for creating vascular access for HD than Diastat grafts.

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Short- to midterm results of early cannulation arteriovenous grafts (Gore® ACUSEAL) for hemodialysis: Experience with the ACUSEAL in a Japanese cohort

The Journal of Vascular Access ◽

10.1177/1129729820974250 ◽

2020 ◽

pp. 112972982097425

Author(s):

Kenichi Honma ◽

Daihiko Eguchi

Keyword(s):

Graft Infection ◽

Prosthetic Graft ◽

Skin Incision ◽

Primary Patency ◽

Outer Diameter ◽

Secondary Patency ◽

Complication Rates ◽

Japanese Cohort ◽

Surgical Wounds ◽

Steal Syndrome

Background: In patients without suitable vasculature for autologous arteriovenous fistula, vascular access using a prosthetic graft is an option for hemodialysis. Gore® ACUSEAL Vascular graft is an early cannulation arteriovenous graft (AVG) that allows early puncture within 24 h after surgery. We aimed to report the outcomes of using this graft in patients from a single center. Methods: This study included 113 patients who underwent surgery for a new AVG using ACUSEAL, between December 2015 and December 2017, and were followed up. The primary outcomes were primary patency, assisted-primary patency, and secondary patency. Secondary outcomes were postoperative complications such as graft infection and steal syndrome. Results: Of the 113 patients, 60 were male and 53 were female. The average age was 74.4 ± 10.7 years. We could cannulate 69.1% of patients within 24 h. The average follow-up period was 20.1 ± 10.8 months. The primary patency rates after 3 months, 6 months, and 1 year were 76.2%, 60.4%, and 33.8%, respectively. The assisted-primary patency rates after 3 months, 6 months, and 1 year were 88.8%, 73.2%, and 58.9%, respectively. The secondary patency rates after 3 months, 6 months, and 1 year were 100%, 100%, and 98.8%, respectively. Fourteen patients (12.4%) developed graft infection and two patients (1.8%) developed steal syndrome. Conclusion: In our study, ACUSEAL showed satisfactory patency and acceptable complication rates in the short to medium term, similar to previous studies. ACUSEAL is beneficial for surgeons who are familiar with using AVG and for medical staff who control bleeding after dialysis. However, due to the large outer diameter of the graft, surgical wounds might become dehiscent, and careful designing of the subcutaneous graft route is necessary. It might be possible to reduce the rate of graft infection by planning the site and skin incision.

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The Reverse J Arteriovenous Graft Configuration for Hemodialysis Access: Rationale, Technique, and Outcomes

The American Surgeon ◽

10.1177/000313480807400709 ◽

2008 ◽

Vol 74 (7) ◽

pp. 620-625

Author(s):

David L. Cull ◽

Christopher G. Carsten ◽

Corey A. Kalbaugh ◽

John W. York ◽

Ted R. Campbell ◽

...

Keyword(s):

Vascular Access ◽

Graft Patency ◽

Fundamental Principle ◽

Secondary Patency ◽

Access Site ◽

Venous Outflow ◽

Term Survival ◽

Graft Placement ◽

Av Graft

The long-term survival of patients on hemodialysis is often limited by the exhaustion of vascular access sites. A fundamental principle of vascular access surgery is that the arteriovenous (AV) access be placed as far distally in the arm as possible. This principle enhances the secondary patency of the AV grafts by preserving the proximal veins for AV graft revision and provides venous outflow for a new AV access to be placed more proximally in the extremity. The standard straight and looped AV graft configurations violate this principle by bypassing long segments of vein in the extremity that could be used for AV graft revision or new AV graft placement. We have developed a novel AV graft configuration that preserves venous outflow and enhances the longevity of each AV access site. The purpose of this review is to describe the reverse J AV graft technique and to report our outcomes with the procedure. Between February 2004 and April 2007, 26 AV grafts were placed using the reverse J configuration. Eighteen (69%) AV grafts were placed in the upper arm, 7 (27%) were placed in the forearm, and 1 (4%) was placed in the thigh. Median follow-up was 320 days. The secondary AV graft patency was 90 per cent at 6 months, 84 per cent at 12 months, and 84 per cent at 18 months. Five AV grafts were subsequently revised to a loop configuration. Overall patient survival was 85 per cent at 6 months, 68 per cent at 12 months, and 62 per cent at 18 months. Compared with the standard straight and looped AV graft configurations, the reverse J AV graft configuration preserves the length of venous outflow in the extremity for AV graft revision or new AV graft placement. Therefore, the reverse J configuration enhances the secondary patency of AV graft patency and AV access site longevity.

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Plasminogen Activation In Vivo upon Intravenous Infusion of DDAVP

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648390 ◽

1992 ◽

Vol 67 (01) ◽

pp. 111-116 ◽

Cited By ~ 64

Author(s):

Marcel Levi ◽

Jan Paul de Boer ◽

Dorina Roem ◽

Jan Wouter ten Cate ◽

C Erik Hack

Keyword(s):

Monoclonal Antibodies ◽

Plasminogen Activator ◽

Plasma Levels ◽

Fold Increase ◽

Fibrinolytic System ◽

Plasminogen Activation ◽

Plasminogen Activator Activity ◽

Insight Into

SummaryInfusion of desamino-d-arginine vasopressin (DDAVP) results in an increase in plasma plasminogen activator activity. Whether this increase results in the generation of plasmin in vivo has never been established.A novel sensitive radioimmunoassay (RIA) for the measurement of the complex between plasmin and its main inhibitor α2 antiplasmin (PAP complex) was developed using monoclonal antibodies preferentially reacting with complexed and inactivated α2-antiplasmin and monoclonal antibodies against plasmin. The assay was validated in healthy volunteers and in patients with an activated fibrinolytic system.Infusion of DDAVP in a randomized placebo controlled crossover study resulted in all volunteers in a 6.6-fold increase in PAP complex, which was maximal between 15 and 30 min after the start of the infusion. Hereafter, plasma levels of PAP complex decreased with an apparent half-life of disappearance of about 120 min. Infusion of DDAVP did not induce generation of thrombin, as measured by plasma levels of prothrombin fragment F1+2 and thrombin-antithrombin III (TAT) complex.We conclude that the increase in plasminogen activator activity upon the infusion of DDAVP results in the in vivo generation of plasmin, in the absence of coagulation activation. Studying the DDAVP induced increase in PAP complex of patients with thromboembolic disease and a defective plasminogen activator response upon DDAVP may provide more insight into the role of the fibrinolytic system in the pathogenesis of thrombosis.

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Faculty Opinions recommendation of Prosthetic vascular graft infection: the role of 18F-FDG PET/CT.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1089552.544806 ◽

2007 ◽

Author(s):

Barry Shulkin

Keyword(s):

Fdg Pet ◽

Vascular Graft ◽

Graft Infection ◽

Vascular Graft Infection ◽

Pet Ct ◽

18F Fdg ◽

Fdg Pet Ct ◽

Prosthetic Vascular Graft Infection

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The SOS Error-Prone DNA Polymerase V Mutasome and β-Sliding Clamp Acting in Concert on Undamaged DNA and during Translesion Synthesis

Cells ◽

10.3390/cells10051083 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1083

Author(s):

Adhirath Sikand ◽

Malgorzata Jaszczur ◽

Linda B. Bloom ◽

Roger Woodgate ◽

Michael M. Cox ◽

...

Keyword(s):

Dna Synthesis ◽

Dna Polymerase ◽

Pathogenic Bacteria ◽

Fold Increase ◽

Translesion Dna Synthesis ◽

Sliding Clamp ◽

Pol V ◽

Dna Polymerase V ◽

Acting In Concert

In the mid 1970s, Miroslav Radman and Evelyn Witkin proposed that Escherichia coli must encode a specialized error-prone DNA polymerase (pol) to account for the 100-fold increase in mutations accompanying induction of the SOS regulon. By the late 1980s, genetic studies showed that SOS mutagenesis required the presence of two “UV mutagenesis” genes, umuC and umuD, along with recA. Guided by the genetics, decades of biochemical studies have defined the predicted error-prone DNA polymerase as an activated complex of these three gene products, assembled as a mutasome, pol V Mut = UmuD’2C-RecA-ATP. Here, we explore the role of the β-sliding processivity clamp on the efficiency of pol V Mut-catalyzed DNA synthesis on undamaged DNA and during translesion DNA synthesis (TLS). Primer elongation efficiencies and TLS were strongly enhanced in the presence of β. The results suggest that β may have two stabilizing roles: its canonical role in tethering the pol at a primer-3’-terminus, and a possible second role in inhibiting pol V Mut’s ATPase to reduce the rate of mutasome-DNA dissociation. The identification of umuC, umuD, and recA homologs in numerous strains of pathogenic bacteria and plasmids will ensure the long and productive continuation of the genetic and biochemical journey initiated by Radman and Witkin.

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Health research capacity in Nepal: Analysis of the trend and the role of local researchers

Tropical Doctor ◽

10.1177/0049475520982770 ◽

2021 ◽

pp. 004947552098277

Author(s):

Madhu Kharel ◽

Alpha Pokharel ◽

Krishna P Sapkota ◽

Prasant V Shahi ◽

Pratisha Shakya ◽

...

Keyword(s):

Health Research ◽

Fold Increase ◽

Research Capacity ◽

Rapid Review ◽

Evidence Based ◽

Middle Income ◽

Middle Income Countries ◽

Health Related ◽

Evidence Based Decision Making

Evidence-based decision-making is less common in low- and middle-income countries where the research capacity remains low. Nepal, a lower-middle-income country in Asia, is not an exception. We conducted a rapid review to identify the trend of health research in Nepal and found more than seven-fold increase in the number of published health-related articles between 2000 and 2018. The proportion of articles with Nepalese researchers as the first authors has also risen over the years, though they are still only in two-thirds of the articles in 2018.

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Factors associated with infrainguinal bypass graft patency at 1-year; a retrospective analysis of a single centre experience

Perfusion ◽

10.1177/0267659121995760 ◽

2021 ◽

pp. 026765912199576

Author(s):

Pasha Normahani ◽

Ismail Yusuf Anwar ◽

Alona Courtney ◽

Amish Acharya ◽

Viknesh Sounderajah ◽

...

Keyword(s):

Retrospective Analysis ◽

Patency Rate ◽

Bypass Graft ◽

Graft Patency ◽

Primary Patency ◽

Rank Test ◽

Secondary Patency ◽

Factors Associated ◽

Independent Variables ◽

Secondary Patency Rate

Introduction: The aim of this study was to identify factors associated with primary graft patency 1 year following open lower limb revascularisation (LLR) at a tertiary referral vascular service. Methods: A retrospective analysis of patients undergoing infra-inguinal bypass surgery between January 2016 and May 2017 at a tertiary vascular centre (St Mary’s Hospital, London) was performed. Data regarding patient demographics, comorbidities, type of operation and post-operative anti-thrombotic strategy were collected. Quality of run-off score was assessed from pre-operative imaging. Results: Seventy-seven cases were included in the analysis. Overall, the primary patency rate at 1-year was 63.6% ( n = 49/77) and the secondary patency rate was 67.5% ( n = 52/77). Independent variables with statistically significant inferior patency rates at 1-year were (1) bypasses with below knee targets (p = 0.0096), (2) chronic limb threatening ischaemia indication (p = 0.038), (3) previous ipsilateral revascularisation (p < 0.001) and (4) absence of hypertension history (p = 0.041). There was also a trend towards significance for American Society of Anesthesiologists (ASA) grade (p = 0.06). Independent variables with log-rank test p values of <0.1 were included in a Cox proportional hazards model. The only variable with a statistically significant impact on primary patency rates was previous open or endovascular ipsilateral revascularisation (HR 2.44 (1.04–5.7), p = 0.04). Conclusion: At 1-year follow-up, previous ipsilateral revascularisation was the most significant factor in affecting patency rates. Patients in this subgroup should therefore be deemed high-risk, which should be reflected in the informed consent and peri-operative management.

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Arsenic Removal by Advanced Electrocoagulation Processes: The Role of Oxidants Generated and Kinetic Modeling

Catalysts ◽

10.3390/catal10080928 ◽

2020 ◽

Vol 10 (8) ◽

pp. 928

Author(s):

Micah Flor V. Montefalcon ◽

Meliton R. Chiong ◽

Augustus C. Resurreccion ◽

Sergi Garcia-Segura ◽

Joey D. Ocon

Keyword(s):

Kinetic Modeling ◽

Arsenic Removal ◽

Fold Increase ◽

Electrochemical Treatment ◽

Promising Alternative ◽

Iron Electrodes ◽

Removal Capacity ◽

Naturally Occurring ◽

Treatment Technologies

Arsenic (As) is a naturally occurring element in the environment that poses significant risks to human health. Several treatment technologies have been successfully used in the treatment of As-contaminated waters. However, limited literature has explored advanced electrocoagulation (EC) processes for As removal. The present study evaluates the As removal performance of electrocoagulation, electrochemical peroxidation (ECP), and photo-assisted electrochemical peroxidation (PECP) technologies at circumneutral pH using electroactive iron electrodes. The influence of As speciation and the role of oxidants in As removal were investigated. We have identified the ECP process to be a promising alternative for the conventional EC with around 4-fold increase in arsenic removal capacity at a competitive cost of 0.0060 $/m3. Results also indicated that the rate of As(III) oxidation at the outset of electrochemical treatment dictates the extent of As removal. Both ECP and PECP processes reached greater than 96% As(III) conversion at 1 C/L and achieved 86% and 96% As removal at 5 C/L, respectively. Finally, the mechanism of As(III) oxidation was evaluated, and results showed that Fe(IV) is the intermediate oxidant generated in advanced EC processes, and the contribution of •OH brought by UV irradiation is insignificant.

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