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Kingsmore D, White RD, Mestres G, Stephens M, Calder F, Papadakis G, Aitken E, Jackson A, Inston N, Jones RG, Geddes C, Stevenson K, Szabo L, Thomson P, Stove C, Kasthuri R, Edgar B, Tozzi M, Franchin M, Sivaprakasam R, Karydis N. Recruitment into randomised trials of arteriovenous grafts: A systematic review. J Vasc Access 2024; 25:1069-1080. [PMID: 36905207 DOI: 10.1177/11297298231158413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023] Open
Abstract
Although randomised controlled trials (RCT) are considered the optimal form of evidence, there are relatively few in surgery. Surgical RCT are particularly likely to be discontinued with poor recruitment cited as a leading reason. Surgical RCT present challenges over and above those seen in drug trials as the treatment under study may vary between procedures, between surgeons in one unit, and between units in multi-centred RCT. The most contentious and debated area of vascular access remains the role of arteriovenous grafts, and thus the quality of the data that is used to support opinions, guidelines and recommendations is critical. The aim of this review was to determine the extent of variation in the planning and recruitment in all RCT involving AVG. The findings of this are stark: there have been only 31 RCT performed in 31 years, the vast majority of which exhibited major limitations severe enough to undermine the results. This underlines the need for better quality RCT and data, and further inform the design of future studies. Perhaps most fundamental is the planning for a RCT that accounts for the intended population, the uptake of a RCT and the attrition for the significant co-morbidity in this population.
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Affiliation(s)
- David Kingsmore
- Vascular Surgery, Queen Elizabeth University Hospital, Glasgow, UK
- Renal and Transplant Surgery, Queen Elizabeth University Hospital, Glasgow, UK
| | - Richard D White
- Department of Interventional Radiology, University Hospital of Wales, Cardiff, UK
| | - Gaspar Mestres
- Department of Vascular Surgery, University of Barcelona, Spain
| | - Mike Stephens
- Dialysis Access Team, University Hospital of Wales, Cardiff, UK
| | - Francis Calder
- Renal & Transplant Surgery, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Georgios Papadakis
- Renal & Transplant Surgery, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Emma Aitken
- Renal and Transplant Surgery, Queen Elizabeth University Hospital, Glasgow, UK
| | - Andrew Jackson
- Renal and Transplant Surgery, Queen Elizabeth University Hospital, Glasgow, UK
| | - Nick Inston
- Renal and Transplant Surgery, University Hospital Birmingham, UK
| | - Rob G Jones
- Interventional Radiology, Queen Elizabeth Hospital Birmingham, UK
| | - Colin Geddes
- Department of Nephrology, Queen Elizabeth University Hospital, Glasgow, UK
| | - Karen Stevenson
- Renal and Transplant Surgery, Queen Elizabeth University Hospital, Glasgow, UK
| | - Laszlo Szabo
- Dialysis Access Team, University Hospital of Wales, Cardiff, UK
| | - Peter Thomson
- Department of Nephrology, Queen Elizabeth University Hospital, Glasgow, UK
| | - Callum Stove
- Department of Interventional Radiology, Queen Elizabeth University Hospital, Glasgow, UK
| | - Ram Kasthuri
- Department of Vascular Surgery, University of Insubria, Varesi, Italy
| | - Ben Edgar
- Renal and Transplant Surgery, Queen Elizabeth University Hospital, Glasgow, UK
| | - Matteo Tozzi
- Department of Vascular Surgery, University of Insubria, Varesi, Italy
| | - Marco Franchin
- Department of Vascular Surgery, University of Insubria, Varesi, Italy
| | | | - Nikolaos Karydis
- Department of Renal and Transplant Surgery, University Hospital of Patras, Greece
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Kingsmore DB, Edgar B, Aitken E, Calder F, Franchin M, Geddes C, Inston N, Jackson A, Jones RG, Karydis N, Kasthuri R, Mestres G, Papadakis G, Sivaprakasam R, Stephens M, Stevenson K, Stove C, Szabo L, Thomson PC, Tozzi M, White RD. Quality assurance in surgical trials of arteriovenous grafts for haemodialysis: A systematic review, a narrative exploration and expert recommendations. J Vasc Access 2024:11297298241236521. [PMID: 38501338 DOI: 10.1177/11297298241236521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024] Open
Abstract
BACKGROUND Introducing new procedures and challenging established paradigms requires well-designed randomised controlled trials (RCT). However, RCT in surgery present unique challenges with much of treatment tailored to the individual patient circumstances, refined by experience and limited by organisational factors. There has been considerable debate over the outcomes of arteriovenous grafts (AVG) compared to AVF, but any differences may reflect differing practice and potential variability. It is essential, therefore, when considering an RCT of a novel surgical procedure or device that quality assurance (QA) is defined for both the new approach and the comparator. The aim of this systematic review was to evaluate the QA standards performed in RCT of AVG using a multi-national, multi-disciplinary approach and propose an approach for future RCT. METHOD The methods of this have been previously registered (PROSPERO: CRD420234284280) and published. In summary, a four-stage review was performed: identification of RCT of AVG, initial review, multidisciplinary appraisal of QA methods and reconciliation. QA measures were sought in four areas - generic, credentialing, standardisation and monitoring, with data abstracted by a multi-national, multi-speciality review body. RESULTS QA in RCT involving AVG in all four domains is highly variable, often sub-optimally described and has not improved over the past three decades. Few RCT established or defined a pre-RCT level of experience, none documented a pre-trial education programme, or had minimal standards of peri-operative management, no study had a defined pre-trial monitoring programme, and none assessed technical performance. CONCLUSION QA in RCT is a relatively new area that is expanding to ensure evidence is reliable and reproducible. This review demonstrates that QA has not previously been detailed, but can be measured in surgical RCT of vascular access, and that a four-domain approach can easily be implemented into future RCT.
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Affiliation(s)
- David B Kingsmore
- Renal and Transplant Surgery, Queen Elizabeth University Hospital, Glasgow, UK
- Vascular Surgery, Queen Elizabeth University Hospital, Glasgow, UK
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Ben Edgar
- Renal and Transplant Surgery, Queen Elizabeth University Hospital, Glasgow, UK
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Emma Aitken
- Renal and Transplant Surgery, Queen Elizabeth University Hospital, Glasgow, UK
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Francis Calder
- Renal & Transplant Surgery, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Marco Franchin
- Department of Vascular Surgery, University of Insubria, Varesi, Italy
| | - Colin Geddes
- Department of Nephrology, Queen Elizabeth University Hospital, Glasgow, UK
| | - Nick Inston
- Renal and Transplant Surgery, University Hospital Birmingham, Birmingham, UK
| | - Andrew Jackson
- Renal and Transplant Surgery, Queen Elizabeth University Hospital, Glasgow, UK
| | - Rob G Jones
- Interventional Radiology, Queen Elizabeth Hospital Birmingham, Birmingham, UK
| | - Nikolaos Karydis
- Department of Renal and Transplant Surgery, University of Athens, Athens, Greece
| | - Ram Kasthuri
- Department of Interventional Radiology, Queen Elizabeth University Hospital, Glasgow, UK
| | - Gaspar Mestres
- Department of Vascular Surgery, University of Barcelona, Barcelona, Spain
| | - Georgios Papadakis
- Renal & Transplant Surgery, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | | | - Mike Stephens
- Dialysis Access Team, University Hospital of Wales, Cardiff, UK
| | - Karen Stevenson
- Renal and Transplant Surgery, Queen Elizabeth University Hospital, Glasgow, UK
| | - Callum Stove
- Department of Interventional Radiology, Queen Elizabeth University Hospital, Glasgow, UK
| | - Lazslo Szabo
- Dialysis Access Team, University Hospital of Wales, Cardiff, UK
| | - Peter C Thomson
- Department of Nephrology, Queen Elizabeth University Hospital, Glasgow, UK
| | - Matteo Tozzi
- Department of Vascular Surgery, University of Insubria, Varesi, Italy
| | - Richard D White
- Department of Interventional Radiology, University Hospital of Wales, Cardiff, UK
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Dalio MB, Gomes KEB, Bohatch Júnior MS, Joviliano EE. Tapered reinforced graft and vein cuff in the distal anastomosis as adjunct strategies for infrapopliteal prosthetic bypass graft in chronic limb-threatening ischemia: A case report. SAGE Open Med Case Rep 2023; 11:2050313X231204575. [PMID: 37829350 PMCID: PMC10566265 DOI: 10.1177/2050313x231204575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 09/13/2023] [Indexed: 10/14/2023] Open
Abstract
The great saphenous vein is the optimal conduit for infrapopliteal bypass surgery in chronic limb-threatening ischemia. A prosthetic bypass graft is an acceptable option when the autologous vein is unavailable and the anatomy is not favorable for endovascular therapy. However, the low patency rate of prosthetic grafts calls for adjunct strategies to improve the outcomes. Tapered reinforced grafts and vein cuffs are proposed measures. We herein present a case of a 78-year-old man with chronic limb-threatening ischemia and an extensive necrotic lesion on the dorsum of the left foot. He was successfully treated with a prosthetic bypass using two adjunct strategies to help improve patency: a tapered reinforced graft and a vein cuff in the distal anastomosis. After debridement and partial skin grafting, the wound healed completely in 2 months. The bypass graft was patent for 1 year.
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Williams D, Leuthardt EC, Genin GM, Zayed M. Tailoring of arteriovenous graft-to-vein anastomosis angle to attenuate pathological flow fields. Sci Rep 2021; 11:12153. [PMID: 34108499 PMCID: PMC8190231 DOI: 10.1038/s41598-021-90813-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 05/04/2021] [Indexed: 02/05/2023] Open
Abstract
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.
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Affiliation(s)
- Dillon Williams
- Vascular Surgery Biomedical Research Laboratory, Washington University School of Medicine, Saint Louis, MO, 60613, USA
- Center for Innovation in Neuroscience and Technology, Department of Neurological Surgery, Washington University School of Medicine, Saint Louis, MO, 60613, USA
| | - Eric C Leuthardt
- Center for Innovation in Neuroscience and Technology, Department of Neurological Surgery, Washington University School of Medicine, Saint Louis, MO, 60613, USA
- Department of Biomedical Engineering, Washington University, Saint Louis, MO, 63130, USA
| | - Guy M Genin
- Center for Innovation in Neuroscience and Technology, Department of Neurological Surgery, Washington University School of Medicine, Saint Louis, MO, 60613, USA.
- Department of Biomedical Engineering, Washington University, Saint Louis, MO, 63130, USA.
- NSF Science and Technology Center for Engineering MechanoBiology, Washington University in St. Louis, Saint Louis, USA.
| | - Mohamed Zayed
- Vascular Surgery Biomedical Research Laboratory, Washington University School of Medicine, Saint Louis, MO, 60613, USA.
- Center for Innovation in Neuroscience and Technology, Department of Neurological Surgery, Washington University School of Medicine, Saint Louis, MO, 60613, USA.
- Department of Biomedical Engineering, Washington University, Saint Louis, MO, 63130, USA.
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Miao P, Tan ZL, Tian R, Yao CL, Chen X, Cao F, Chen Z, Yu ZY. Long-term patency and comparisons of venous outflow in hemodialysis forearm arteriovenous grafts. Vascular 2021; 30:238-245. [PMID: 33966507 DOI: 10.1177/17085381211012565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
INTRODUCTION This retrospective study investigated the factors and the effects of different venous outflows on forearm arteriovenous graft patency. METHODS The venous outflow sites included basilic, cephalic, median antecubital, and deep veins. Comparisons among multiple groups were analyzed. FINDINGS A total of 179 patients with forearm loop arteriovenous grafts met the inclusion criteria. Of these, 72 were basilic, 48 were cephalic, 44 were median antecubital, and 15 were deep. The median observation period was 19 months. The survival rate was 84.9% at 24 months and 78.2% at 48 months. Primary, secondary, and assisted primary patency rates for all arteriovenous grafts were 48.9%, 72.4%, and 68.4% at 12 months; 13.8%, 33.9%, and 23.6% at 24 months; and 0.6%, 4.6%, and 2.3% at 48 months, respectively. Differences in primary patency were statistically significant compared with those of secondary and assisted primary patency (P < 0.05). Primary patency rates for cephalic, median antecubital, basilic, and deep were 47.9%, 48.6%, 47.7%, and 40.0% at 12 months and 12.5%, 13.9%, 22.7%, and 0% at 24 months, respectively. Secondary patency rates for cephalic, median antecubital, basilic, and deep were 75.0%, 69.4%, 75.0%, and 73.3% at 12 months and 39.6%, 30.6%, 38.6%, and 13.3% at 24 months, respectively. There was no significant difference in primary thrombosis among basilic, cephalic, median antecubital and deep. There were no significant differences observed in primary or secondary patency rates among all the groups. Stenoses in the venous anastomosis and outflow vein were frequently observed in all types of arteriovenous grafts. Central venous stenosis was most commonly seen in deep (26.67%). On average, 1.9 interventions per patient were performed on the graft to maintain function. CONCLUSION Different venous outflow selections were not associated with long-term patency and the occurrence of thrombosis in hemodialysis forearm loop arteriovenous grafts.
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Affiliation(s)
- Peng Miao
- Department of Vascular Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China.,Department of Vascular Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Zheng-Li Tan
- Department of Vascular Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Ran Tian
- Department of Vascular Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Chen-Liang Yao
- Department of Vascular Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Xin Chen
- Department of Vascular Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Fang Cao
- Department of Vascular Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Zhong Chen
- Department of Vascular Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Zheng-Ya Yu
- Department of Vascular Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
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Jasty VS, Haddad D, Mohan B, Zhou W, Siracuse JJ, Tan TW. Tapered and non-tapered prosthetic grafts in upper extremity dialysis access: A systematic review and meta-analysis. J Vasc Access 2020; 23:42-49. [PMID: 33213273 DOI: 10.1177/1129729820974177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE It is unclear whether tapered arteriovenous grafts (AVGs) are superior to non-tapered AVGs when it comes to preventing upper extremity ischemic steal syndrome. We aimed to evaluate the outcomes of tapered and non-tapered AVGs using systematic review and meta-analysis. METHODS A literature search was systemically performed to identify all English publications from 1999 to 2019 that directly compared the outcomes of upper extremity tapered and non-tapered AVGs. Outcomes evaluated were the primary patency at 1-year (number of studies (n) = 4), secondary patency at 1-year (n = 3), and risk of ischemic steal (n = 5) and infection (n = 4). Effect sizes of individual studies were pooled using random-effects model, and between-study variability was assessed using the I2 statistic. RESULTS Of 5808 studies screened, five studies involving 4397 patients have met the inclusion criteria and included in the analysis. Meta-analyses revealed no significant difference for the risk of ischemic steal syndrome (pooled odds ratio (OR) 0.92, 95% Confidence Incidence (CI) 0.29-2.91, p = 0.89, I2 = 48%) between the tapered and non-tapered upper extremity AVG. The primary patency (OR 1.33, 95% CI 0.93-1.90, p = 0.12, I2 = 10%) and secondary patency at 1-year (OR 1.49, 95% CI 0.84-2.63, p = 0.17, I2 = 13%), and rate of infection (OR 0.62, 95% CI 0.30-1.27, p = 0.19, I2 = 29%) were also similar between the tapered and non-tapered AVG. CONCLUSIONS The risk of ischemic steal syndrome and patency rate are comparable for upper extremity tapered and non-tapered AVGs. This meta-analysis does not support the routine use of tapered graft over non-tapered graft to prevent ischemic steal syndrome in upper extremity dialysis access. However, due to small number of studies and sample sizes as well as limited stratification of outcomes based on risk factors, future studies should take such limitations into account while designing more robust protocols to elucidate this issue.
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Affiliation(s)
| | - David Haddad
- College of Medicine, University of Arizona, Tucson, AZ, USA
| | - Babu Mohan
- College of Medicine, University of Arizona, Tucson, AZ, USA
| | - Wei Zhou
- College of Medicine, University of Arizona, Tucson, AZ, USA
| | - Jeffrey J Siracuse
- Department of Vascular Surgery, Boston University School of Medicine, Boston, MA, USA
| | - Tze-Woei Tan
- College of Medicine, University of Arizona, Tucson, AZ, USA
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Lok CE, Huber TS, Lee T, Shenoy S, Yevzlin AS, Abreo K, Allon M, Asif A, Astor BC, Glickman MH, Graham J, Moist LM, Rajan DK, Roberts C, Vachharajani TJ, Valentini RP. KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update. Am J Kidney Dis 2020; 75:S1-S164. [PMID: 32778223 DOI: 10.1053/j.ajkd.2019.12.001] [Citation(s) in RCA: 1001] [Impact Index Per Article: 250.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 12/09/2019] [Indexed: 02/07/2023]
Abstract
The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for hemodialysis vascular access since 1996. Since the last update in 2006, there has been a great accumulation of new evidence and sophistication in the guidelines process. The 2019 update to the KDOQI Clinical Practice Guideline for Vascular Access is a comprehensive document intended to assist multidisciplinary practitioners care for chronic kidney disease patients and their vascular access. New topics include the end-stage kidney disease "Life-Plan" and related concepts, guidance on vascular access choice, new targets for arteriovenous access (fistulas and grafts) and central venous catheters, management of specific complications, and renewed approaches to some older topics. Appraisal of the quality of the evidence was independently conducted by using a Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, and interpretation and application followed the GRADE Evidence to Decision frameworks. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.
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8
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Kingsmore DB, Stevenson KS, Jackson A, Desai SS, Thompson P, Karydis N, Franchin M, White B, Tozzi M, Isaak A. Arteriovenous Access Graft Infection: Standards of Reporting and Implications for Comparative Data Analysis. Ann Vasc Surg 2020; 63:391-398. [DOI: 10.1016/j.avsg.2019.08.081] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 08/14/2019] [Accepted: 08/14/2019] [Indexed: 11/28/2022]
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9
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Roberts L, Farber A, Jones DW, Woo K, Eslami MH, Simons J, Malas M, Tan TW, Rybin D, Siracuse JJ. Tapered arteriovenous grafts do not provide significant advantage over nontapered grafts in upper extremity dialysis access. J Vasc Surg 2019; 69:1552-1558. [DOI: 10.1016/j.jvs.2018.08.181] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 08/23/2018] [Indexed: 11/29/2022]
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10
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Fumagalli G, Trovato F, Migliori M, Panichi V, De Pietro S. The forearm arteriovenous graft between the brachial artery and the brachial vein as a reliable dialysis vascular access for patients with inadequate superficial veins. J Vasc Surg 2019; 70:199-207.e4. [PMID: 30894304 DOI: 10.1016/j.jvs.2018.10.101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 10/26/2018] [Indexed: 11/15/2022]
Abstract
OBJECTIVE The arteriovenous fistula (AVF) is recommended as the preferred hemodialysis access. However, placing an AVF in all patients may result in poor access outcomes and increased central venous catheter (CVC) use because of increased comorbid conditions, age, and suboptimal vessels. In patients with inadequate superficial veins for AVFs, the use of the brachial veins for creation of forearm arteriovenous grafts (AVGs) has received limited attention. This retrospective study aimed to evaluate outcomes of forearm brachial-brachial AVGs (BB-AVGs) placed in patients with poor superficial veins. METHODS We identified 111 BB-AVGs created in 111 consecutive patients, using standard-walled polytetrafluoroethylene grafts, between January 2010 and December 2015. After excluding 6 patients (non-dialysis initiation, missing information, and death within 1 month), we included 105 patients from 21 dialysis centers. We analyzed primary failures, time to cannulation, patency, complications, and revisions. Patency rates were calculated by the Kaplan-Meier method. The incidence of complications and revisions was expressed as number of events per person-year. RESULTS A total of 105 patients (median age, 69 years) were followed up for a median time of 21.2 months (interquartile range, 9.2-36.5 months). Of the patients, 72.4% were on chronic hemodialysis and had previously undergone one or more access procedures. At the time of BB-AVG placement, prior accesses were 39 AVFs, 20 tunneled CVCs, and 17 AVGs. BB-AVG rates of primary failure and revision before cannulation were 7.6% and 5.7%, respectively. BB-AVGs were cannulated after a median time of 3.4 weeks (interquartile range, 2.8-4.1 weeks). Primary patency rates at 12, 24, and 36 months were 49.5%, 29.5%, and 19.5%. Secondary patency rates at 12, 24, and 36 months were 76.3%, 62.7%, and 54.6%. After cannulation, the incidence of complications and revisions was 1.054 and 0.649 per person-year, respectively. Most complications and interventions were due to thrombosis (0.527 per person-year) or stenosis (0.381 per person-year) and related interventions (0.490 per person-year). A minority of patients experienced AVG infections (0.052 per person-year), with only two requiring access removal. CONCLUSIONS In patients with poor superficial veins, the forearm BB-AVG is a reliable access because of low access-related morbidity and considerable long-term access survival. BB-AVG placement has the advantage of preserving proximal vessels. In these patients, such an approach can delay both rapid exhaustion of vascular sites and early recourse to CVC permanent use.
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Affiliation(s)
- Giordano Fumagalli
- Nephrology and Dialysis Unit, USL Toscana Nord Ovest-Versilia Hospital, Lido di Camaiore, Lucca, Italy.
| | - Fabio Trovato
- Nephrology and Dialysis Unit, USL Toscana Nord Ovest-Versilia Hospital, Lido di Camaiore, Lucca, Italy; Department of Mathematics and Computer Science, Freie Universität Berlin, Berlin, Germany
| | - Massimiliano Migliori
- Nephrology and Dialysis Unit, USL Toscana Nord Ovest-Versilia Hospital, Lido di Camaiore, Lucca, Italy
| | - Vincenzo Panichi
- Nephrology and Dialysis Unit, USL Toscana Nord Ovest-Versilia Hospital, Lido di Camaiore, Lucca, Italy
| | - Stefano De Pietro
- Nephrology and Dialysis Unit, USL Toscana Nord Ovest-Versilia Hospital, Lido di Camaiore, Lucca, Italy
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11
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Ene-Iordache B, Remuzzi A. Blood Flow in Idealized Vascular Access for Hemodialysis: A Review of Computational Studies. Cardiovasc Eng Technol 2017; 8:295-312. [PMID: 28664239 DOI: 10.1007/s13239-017-0318-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 06/26/2017] [Indexed: 10/19/2022]
Abstract
Although our understanding of the failure mechanism of vascular access for hemodialysis has increased substantially, this knowledge has not translated into successful therapies. Despite advances in technology, it is recognized that vascular access is difficult to maintain, due to complications such as intimal hyperplasia. Computational studies have been used to estimate hemodynamic changes induced by vascular access creation. Due to the heterogeneity of patient-specific geometries, and difficulties with obtaining reliable models of access vessels, idealized models were often employed. In this review we analyze the knowledge gained with the use of computational such simplified models. A review of the literature was conducted, considering studies employing a computational fluid dynamics approach to gain insights into the flow field phenotype that develops in idealized models of vascular access. Several important discoveries have originated from idealized model studies, including the detrimental role of disturbed flow and turbulent flow, and the beneficial role of spiral flow in intimal hyperplasia. The general flow phenotype was consistent among studies, but findings were not treated homogeneously since they paralleled achievements in cardiovascular biomechanics which spanned over the last two decades. Computational studies in idealized models are important for studying local blood flow features and evaluating new concepts that may improve the patency of vascular access for hemodialysis. For future studies we strongly recommend numerical modelling targeted at accurately characterizing turbulent flows and multidirectional wall shear disturbances.
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Affiliation(s)
- Bogdan Ene-Iordache
- Laboratory of Biomedical Technologies, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Via G.B. Camozzi 3, 24020, Ranica, BG, Italy.
| | - Andrea Remuzzi
- Laboratory of Biomedical Technologies, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Via G.B. Camozzi 3, 24020, Ranica, BG, Italy.,Department of Management, Information and Production and Engineering, University of Bergamo, Dalmine, BG, Italy
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12
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Han S, Seo PW, Ryu JW. Surgical Outcomes of Forearm Loop Arteriovenous Fistula Formation Using Tapered versus Non-Tapered Polytetrafluoroethylene Grafts. THE KOREAN JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY 2017; 50:30-35. [PMID: 28180100 PMCID: PMC5295480 DOI: 10.5090/kjtcs.2017.50.1.30] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 11/04/2016] [Accepted: 11/14/2016] [Indexed: 11/17/2022]
Abstract
Background Tapered grafts, which have a smaller diameter on the arterial side, have been increasingly used for arteriovenous fistula (AVF) formation. We compared the outcomes of 4–6-mm tapered and 6-mm straight forearm loop arteriovenous grafts. Methods A total of 103 patients receiving forearm loop arteriovenous grafts between March 2005 and March 2015 were retrospectively analyzed and separated into 2 groups (group A, 4- to 6-mm tapered grafts, n=78; group B, 6-mm straight grafts, n=25). In each group, complications and patency rates after surgery were assessed. Results Clinical characteristics and laboratory results, except for cerebrovascular disease history (group A, 7.7%; group B, 28.0%; p=0.014), were similar between the groups. No significant differences were found for individual complications. Kaplan-Meier survival analysis revealed no significant differences in 1-year, 3-year, and 5-year patency rates between groups (61.8%, 44.9%, and 38.5% vs. 62.7%, 41.1%, and 35.3%, respectively). Conclusion We found no significant differences in complication and patency rates between the tapered and straight graft groups. If there are no differences in complication and patency between the two graft types, tapered grafts may be a valuable option for AVF formation in light of their other advantages.
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Affiliation(s)
- Sun Han
- Department of Thoracic and Cardiovascular Surgery, Dankook University College of Medicine
| | - Pil Won Seo
- Department of Thoracic and Cardiovascular Surgery, Dankook University College of Medicine
| | - Jae-Wook Ryu
- Department of Thoracic and Cardiovascular Surgery, Dankook University College of Medicine
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Alamshah SM, Nazari I, Nahidi A, Sametzadeh M, Khodabakhshi S. Prosthetic Hemodialysis Access-induced Distal Hand Ischemia and its Contributors in Diabetics. Indian J Nephrol 2017; 27:199-204. [PMID: 28553040 PMCID: PMC5434686 DOI: 10.4103/0971-4065.202836] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Avoidance of hand ischemia in the construction of prosthetic access for hemodialysis in diabetics that have no suitable vein for arteriovenous fistula is appreciated. Taper type may be an appropriately matched conduit to prevent its occurrence. This is a prospective controlled trial of 38 selected diabetics requiring hemodialysis, who were referred to our clinic during a period of 6 months. The aim of the study was to evaluate the efficacy of tapered grafts in preventing distal hand hypoperfusion and determining its most likely contributors. In 18 intervening cases, taper 4 mm × 7 mm and in twenty cases (control group), standard 6 mm polytetrafluoroethylene as straight Brachial-Axillary access was used. Graft flow rates, artery and vein diameters, and mean arterial pressure were included for evaluation. Within the control group, 11 patients (55%) (7 cases Grade 1, 3 Grade 2, 1 Grade 3) and in intervening group, 2 cases (11%) (Grade 1, Grade 3) developed Steal syndrome. There was no significant difference in the mean flow rates (P = 0.82). Increased risk of distal hypoperfusion was observed in the control group when flow rates were more than 1000 ml/min. Arterial diameters (P = 0.011) and mean arterial pressure (P = 0.05) were found to be important contributing factors. Taper grafts causes reduced incidence of distal hand hypoperfusion. When artery diameter was <6 mm and mean arterial pressure lower than 100 mmHg and the index (brachial artery diameter × mean arterial pressure) was under 500, distal hand ischemia occurred in standard and tapper type. We therefore recommend selective usage of taper grafts in diabetics with diminished distal hand pulses, considering the contributing factors when fistula first is not feasible.
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Affiliation(s)
- S M Alamshah
- Department of Vascular Surgery and Trauma and Transplantation, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - I Nazari
- Department of Vascular Surgery and Trauma and Transplantation, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - A Nahidi
- Department of Surgery, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - M Sametzadeh
- Department of Radiology, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - S Khodabakhshi
- Department of Vascular Surgery and Trauma and Transplantation, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
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14
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Bioinspired helical graft with taper to enhance helical flow. J Biomech 2016; 49:3643-3650. [DOI: 10.1016/j.jbiomech.2016.09.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 09/09/2016] [Accepted: 09/19/2016] [Indexed: 11/23/2022]
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15
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Suemitsu K, Iida O, Shiraki T, Suemitsu S, Murakami M, Miyamoto M, Izumi M, Nakanishi T. Predicting loss of patency after forearm loop arteriovenous graft. J Vasc Surg 2016; 64:395-401. [DOI: 10.1016/j.jvs.2016.02.049] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 02/19/2016] [Indexed: 11/27/2022]
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16
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Graft Modification Strategies to Improve Patency of Prosthetic Arteriovenous Grafts for Hemodialysis. J Vasc Access 2016; 17 Suppl 1:S85-90. [DOI: 10.5301/jva.5000526] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/30/2015] [Indexed: 11/20/2022] Open
Abstract
Prosthetic arteriovenous grafts (AVGs) are indicated for vascular access for long-term hemodialysis in patients in whom creation or maintenance of an arteriovenous fistula (AVF) has failed or is contraindicated. AVGs have an inferior long-term patency as compared to AVFs. To ameliorate patency rates of prosthetic AVGs, different strategies have emerged to improve graft materials. This review aims to describe current strategies and future perspectives on graft modification, by graft geometry, drug coatings and graft surface technology, to improve AVG patency.
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17
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Farber A, Tan TW, Hu B, Dember LM, Beck GJ, Dixon BS, Kusek JW, Feldman HI. The effect of location and configuration on forearm and upper arm hemodialysis arteriovenous grafts. J Vasc Surg 2015; 62:1258-64. [PMID: 26254823 DOI: 10.1016/j.jvs.2015.06.132] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 06/02/2015] [Indexed: 11/27/2022]
Abstract
OBJECTIVE The arteriovenous graft (AVG) is most often used in hemodialysis patients when an autogenous fistula is not feasible. The optimal location (forearm or upper arm) and configuration (loop or straight) of AVGs are not known. To evaluate relationships of AVG location and configuration with patency, we conducted a secondary analysis using data from a randomized, placebo-controlled trial of dipyridamole plus aspirin for newly placed AVG. METHODS Participants of the Dialysis Access Consortium (DAC) Graft Study with newly placed upper extremity prosthetic grafts involving the brachial artery were studied. Multivariable analyses adjusting for trial treatment group, center, gender, race, body mass index, diabetes, current treatment with chronic dialysis, and prior arteriovenous vascular access or central venous catheter were performed to compare outcomes of forearm (fAVG) and upper arm (uAVG) grafts, including loss of primary unassisted patency (LPUP) and cumulative primary graft failure (CGF). Subgroup analyses of graft configuration and outflow vein used were also conducted. RESULTS A total of 508 of the 649 participants (78%) enrolled in the trial had an upper extremity brachial artery graft placed, 255 with fAVG and 253 with uAVG. Participants with fAVG were less often male (33% vs 43%; P = .03), African American (62% vs 78%; P < .001), and receiving dialysis at the time of surgery (62% vs 80%; P < .001). Participants with fAVG had a higher mean body mass index (33 vs 29; P < .001). The LPUP (fAVG 70% vs uAVG 78%; P = .07) and CGF (33% vs 36%; P = .91) were similar between fAVG and uAVG at 1-year follow-up. In multivariable analysis, AVG location (uAVG vs fAVG) was not associated with LPUP (hazard ratio, 1.21; 95% confidence interval, 0.90-1.63; P = .20) or CGF (hazard ratio, 1.36; 95% confidence interval, 0.94-1.97; P = .10). LPUP did not differ significantly between fAVG and uAVG among subgroups based on AVG configuration (P = 1.00) or outflow vein used (P = .16). CONCLUSIONS Patency was comparable between fAVG and uAVG despite the larger caliber veins often encountered in the upper arm in carefully selected patients. Our findings support the traditional view that, in order to preserve a maximal number of access sites, the forearm location should be considered first before resorting to an upper arm graft.
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Affiliation(s)
- Alik Farber
- Division of Vascular and Endovascular Surgery, Boston University Medical Center, Boston, Mass.
| | - Tze-Woei Tan
- Division of Vascular Surgery, Louisiana State University Shreveport Health Sciences Center, Shreveport, La
| | - Bo Hu
- Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, Ohio
| | - Laura M Dember
- Renal, Electrolyte and Hypertension Division, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pa
| | - Gerald J Beck
- Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, Ohio
| | | | - John W Kusek
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Md
| | - Harold I Feldman
- Renal, Electrolyte and Hypertension Division, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pa; Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pa
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18
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Abstract
Arteriovenous (AV) grafts are required for hemodialysis access when options for native fistulas have been fully exhausted, where they continue to play an important role in hemodialysis patients, offering a better alternative to central vein catheters. When planning autogenous accesses using Doppler ultrasound, adequate arterial inflow and venous outflow must be consciously preserved for future access creation with grafts. Efforts to improve graft patency include changing graft configuration, graft biology and hemodynamics. Industry offers early cannulation grafts to reduce central catheter use and a bioengineered graft is undergoing clinical studies. Although the outcome of AV grafts is inferior to fistulas, grafts can provide long-term hemodialysis access that is a better alternative to central venous catheters. AV grafts have significant drawbacks, mainly poor patency, infection and cost but also have some advantages: early maturation, ease of creation and needling and widespread availability. The outcome of AV graft surgery is variable from center to center. The primary patency rate for AV grafts is 58% at 6 months and the secondary patency rate is 76% at 6 months and 55% at 18 months. There are centers of excellence that report a 1 year secondary patency rate of up to 91%. In this review of the use of AV grafts for hemodialysis access in the upper extremities, technical issues involved in planning the access and performing the surgery in its different configurations are discussed and the role of surveillance and maintenance with their attendant surgical and radiological interventions is described.
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Early Experience with a Newly Developed Electrospun Polycarbonate-urethane Vascular Graft for Hemodialysis Access. J Vasc Access 2013; 14:252-6. [DOI: 10.5301/jva.5000128] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2012] [Indexed: 11/20/2022] Open
Abstract
Purpose In this pilot study, we tested a newly developed electrospun multilayered, self-sealing graft, AVflo™, specifically designed for early hemodialysis access. Methods Ten eligible consenting patients had a polycarbonate-urethane graft (AVflo™) implanted and were followed up prospectively for at least six months. Performance measures included graft patency, complications and time to first cannulation. Mean age of the patients was 66.7 ± 10 years. Chronic glomerulonephritis was the most common cause of renal failure. A total of 70% of the patients had a history of previous vascular access and 40% history of minimally invasive radiologic procedures for patency maintenance. In 40% of the cases the need for AV graft implantation was because of recurrent infections from permanent catheter for dialysis. Seven grafts were placed in the upper arm and three in the thigh. Mean follow up was 230 ± 75 days. Results There were no systemic or local reactions to the graft and we did not report any graft infections. Two grafts thrombosed because of severe bleeding post-cannulation due to an incorrect needle puncture. Both grafts were successfully thrombectomized. Primary and secondary patency rates at six months were 60% and 78%, respectively. These patency rates were comparable to those reported for other polyether-urethane and ePTFE grafts. Median time to first cannulation was seven days (3-21) and all puncture sites sealed in less than five minutes. Conclusions This newly developed electrospun polycarbonate-urethane graft is safe in humans, permits early access obviating the need for venous catheters, and has equivalent patency as other prosthetic grafts.
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20
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[Vascular grafts as access for hemodialysis]. Chirurg 2012; 83:785-92. [PMID: 22930063 DOI: 10.1007/s00104-012-2304-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Prosthetic arteriovenous grafts have an inferior patency rate and greater morbidity than those with autogenous vessels and are therefore considered as secondary or tertiary vascular access for hemodialysis in patients with fatigued or unsuitable superficial arm veins. Prior access planning in accordance of patient characteristics, careful operative procedure and appropriate revision of complications can ensure long-term functioning of a vascular access using a large variety of possible prosthetic conduits. Arteriovenous grafts remain essential in vascular access surgery and their role may be increasing with higher comorbidities of patients and should be preferred to tunnelled cuffed catheters. This article reviews the indications, alternative configurations and characteristics of arteriovenous grafts.
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21
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Stone PA, Mousa AY, Campbell JE, AbuRahma AF. Dialysis access. Ann Vasc Surg 2012; 26:747-53. [PMID: 22296951 DOI: 10.1016/j.avsg.2011.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 11/07/2011] [Indexed: 10/14/2022]
Abstract
Although hemodialysis access procedures are considered the most common vascular procedures performed by either general or vascular surgeons, there is a paucity of level-one evidence in the literature. Randomized controlled trials are limited, and most of these studies have small sample sizes compared with other areas of vascular surgery, that is, carotid or aneurysm studies. We summarize the results of the world's literature for arteriovenous access in table format as a tool for those specialists managing patients with arteriovenous access procedures.
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22
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Prichard HL, Manson RJ, DiBernardo L, Niklason LE, Lawson JH, Dahl SLM. An early study on the mechanisms that allow tissue-engineered vascular grafts to resist intimal hyperplasia. J Cardiovasc Transl Res 2011; 4:674-82. [PMID: 21748530 PMCID: PMC3175038 DOI: 10.1007/s12265-011-9306-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 06/26/2011] [Indexed: 11/29/2022]
Abstract
Intimal hyperplasia is one of the prominent failure mechanisms for arteriovenous fistulas and arteriovenous access grafts. Human tissue-engineered vascular grafts (TEVGs) were implanted as arteriovenous grafts in a novel baboon model. Ultrasound was used to monitor flow rates and vascular diameters throughout the study. Intimal hyperplasia in the outflow vein of TEVGs was assessed at the anastomosis and at juxta-anastomotic regions via histological analysis, and was compared to intimal hyperplasia with polytetrafluoroethylene (PTFE) grafts in the baboon model and in literature reports from other animal models. Less venous intimal hyperplasia was observed in histological sections with arteriovenous TEVGs than with arteriovenous PTFE grafts. TEVGs were associated with a mild, noninflammatory intimal hyperplasia. The extent of intimal tissue that formed with TEVG placement correlated with the rate of blood flow through tissue engineered vascular grafts at 2 weeks postimplant. Outflow vein dilatation was observed with increased flow rate. Both mid-graft flow rates and outflow vein diameters reached a plateau by week 4, which suggested that venous remodeling and intimal hyperplasia largely occurred within the first 4 weeks of implant in the baboon model. Given their compliant and noninflammatory nature, TEVGs appear resistant to triggers for venous intimal hyperplasia that are common for PTFE arteriovenous grafts, including (1) abundant proinflammatory macrophage populations that are associated with PTFE grafts and (2) compliance mismatch between PTFE grafts and the outflow vein. Our findings suggest that arteriovenous TEVGs develop only a mild form of venous intimal hyperplasia, which results from the typical hemodynamic changes that are associated with arteriovenous settings.
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Affiliation(s)
| | - Roberto J. Manson
- Department of Surgery, Duke University Medical Center, Durham, NC USA
| | - Louis DiBernardo
- Department of Pathology, Duke University Medical Center, Durham, NC USA
| | - Laura E. Niklason
- Departments of Anesthesiology and Biomedical Engineering, Yale University, New Haven, CT USA
| | - Jeffrey H. Lawson
- Departments of Surgery and Pathology, Duke University Medical Center, Durham, NC USA
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23
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Manos TA, Sokolis DP, Giagini AT, Davos CH, Kakisis JD, Kritharis EP, Stergiopulos N, Karayannacos PE, Tsangaris S. Local Hemodynamics and Intimal Hyperplasia at the Venous Side of a Porcine Arteriovenous Shunt. ACTA ACUST UNITED AC 2010; 14:681-90. [DOI: 10.1109/titb.2010.2040288] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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24
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Modifying peripheral IV catheters with side holes and side slits results in favorable changes in fluid dynamic properties during the injection of iodinated contrast material. AJR Am J Roentgenol 2009; 193:970-7. [PMID: 19770318 DOI: 10.2214/ajr.09.2521] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was to compare a standard peripheral end-hole angiocatheter with those modified with side holes or side slits using experimental optical techniques to qualitatively compare the contrast material exit jets and using numeric techniques to provide flow visualization and quantitative comparisons. MATERIALS AND METHODS A Schlieren imaging system was used to visualize the angiocatheter exit jet fluid dynamics at two different flow rates. Catheters were modified by drilling through-and-through side holes or by cutting slits into the catheters. A commercial computational fluid dynamics package was used to calculate numeric results for various vessel diameters and catheter orientations. RESULTS Experimental images showed that modifying standard peripheral IV angiocatheters with side holes or side slits qualitatively changed the overall flow field and caused the exiting jet to become less well defined. Numeric calculations showed that the addition of side holes or slits resulted in a 9-30% reduction of the velocity of contrast material exiting the end hole of the angiocatheter. With the catheter tip directed obliquely to the wall, the maximum wall shear stress was always highest for the unmodified catheter and was always lowest for the four-side-slit catheter. CONCLUSION Modified angiocatheters may have the potential to reduce extravasation events in patients by reducing vessel wall shear stress.
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25
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Katzman HE, McLafferty RB, Ross JR, Glickman MH, Peden EK, Lawson JH. Initial experience and outcome of a new hemodialysis access device for catheter-dependent patients. J Vasc Surg 2009; 50:600-7, 607.e1. [PMID: 19628360 DOI: 10.1016/j.jvs.2009.04.014] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2008] [Revised: 03/16/2009] [Accepted: 04/06/2009] [Indexed: 10/20/2022]
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26
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Hollenbeck M, Mickley V, Brunkwall J, Daum H, Haage P, Ranft J, Schindler R, Thon P, Vorwerk D. Gefäßzugang zur Hämodialyse. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/s11560-009-0281-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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27
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A randomized multicenter study of the outcome of brachial-basilic arteriovenous fistula and prosthetic brachial-antecubital forearm loop as vascular access for hemodialysis. J Vasc Surg 2008; 47:395-401. [DOI: 10.1016/j.jvs.2007.09.063] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 09/26/2007] [Accepted: 09/29/2007] [Indexed: 11/23/2022]
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Abstract
Vascular access thrombosis in the hemodialysis patient leads to significant cost and morbidity. Fistula patency supersedes graft patency, therefore obtaining a mature functioning fistula in patients approaching end-stage renal disease (ESRD) by early patient education and referral needs to be practiced. Current methods to maintain vascular access patency rely on early detection and radiologic or surgical prevention of thrombosis. Study of thrombosis biology has elucidated other potential targets for the prophylaxis of vascular access thrombosis. The goal of this review is to examine the current available methods for vascular access thrombosis prophylaxis.
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Affiliation(s)
- Devasmita Choudhury
- Department of Medicine, University of Texas Southwestern Medical School, VA North Texas Health Care System, Dallas, Texas 75216, USA.
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29
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Van Tricht I, De Wachter D, Tordoir J, Verdonck P. Comparison of the hemodynamics in 6mm and 4-7 mm hemodialysis grafts by means of CFD. J Biomech 2006; 39:226-36. [PMID: 16321624 DOI: 10.1016/j.jbiomech.2004.12.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2004] [Accepted: 12/07/2004] [Indexed: 11/24/2022]
Abstract
The aim of our study is to investigate with computational fluid dynamics (CFD) whether different arterial anastomotic geometries result in a different hemodynamics at the arterial (AA) and venous anastomosis (VA) of hemodialysis vascular access grafts. We have studied a 6mm graft (CD) and a 4-7 mm graft (TG). A validated three-dimensional CFD model is developed to simulate flow in the two graft types. Only the arterial anastomosis (AA) geometry differs. The boundary conditions applied are a periodic velocity signal at the arterial inlet and a periodic pressure wave at the venous outlet. Flow rate is set to 1,000 ml/min. The time dependent Navier-Stokes equations are solved. Wall shear stress (WSS), wall shear stress gradient (WSSG) and pressure gradient (PG) are calculated. Anastomotic flow is asymmetric although the anastomosis geometry is symmetric. The hemodynamic parameters, WSS, WSSG and PG, values at the suture line of the arterial anastomosis of the TG are at least twice as much as in the CD. Comparing the parameters at the two AA indicate that little flow rate increase introduces the risk of hemolysis in the TG whereas the CD is completely free of hemolysis. The hemodynamic parameter values at the venous anastomosis of the CD are 24 till 35% higher compared to the values of the TG. WSS values (> 3 Pa) in the VA are in the critical range for stenosis development in both graft geometries. The zones where the parameters reach extreme values correspond to the locations where intimal hyperplasia formation is reported in literature. In all anastomoses, the hemodynamic parameter levels are in the range where leucocytes and platelets get activated. Our simulations confirm clinical results where TG did not show a better outcome when compared to the CD.
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Affiliation(s)
- Ilse Van Tricht
- Hydraulics Laboratory, Institute Biomedical Technology, Ghent University, Sint-Pietersnieuwstraat 41, Oost-Vlaanderen, Belgium.
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30
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Regarding “Transposition of the brachial vein: A new source for autologous arteriovenous fistulas”. J Vasc Surg 2005. [DOI: 10.1016/j.jvs.2005.01.057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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31
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Kannan RY, Salacinski HJ, Butler PE, Hamilton G, Seifalian AM. Current status of prosthetic bypass grafts: A review. J Biomed Mater Res B Appl Biomater 2005; 74:570-81. [PMID: 15889440 DOI: 10.1002/jbm.b.30247] [Citation(s) in RCA: 335] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Polymers such as Dacron and polytetrafluoroethylene (PTFE) have been used in high flow states with relative success but with limited application at lower flow states. Newer polymers with greater compliance, biomimicry, and ability to evolve into hybrid prostheses, suitable as smaller vessels, are now being introduced. In view of the advances in tissue engineering, this makes possible the creation of an ideal off-the-shelf bypass graft. We present a broad overview of the current state of prosthetic bypass grafts.
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Affiliation(s)
- Ruben Y Kannan
- Biomaterials & Tissue Engineering Centre, University Department of Surgery, Royal Free and University College Medical School, University College London, UK
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32
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Polo JR, Ligero JM, Diaz-Cartelle J, Garcia-Pajares R, Cervera T, Reparaz L. Randomized comparison of 6-mm straight grafts versus 6- to 8-mm tapered grafts for brachial-axillary dialysis access. J Vasc Surg 2004; 40:319-24. [PMID: 15297828 DOI: 10.1016/j.jvs.2004.05.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE This report presents the results of a prospective randomized study that compared 2 grafts of different diameter: 6 mm, and 8 mm tapered to 6 mm at the arterial site, placed in the upper arm for hemodialysis in a selected population of patients younger than 71 years without diabetes. METHODS Seventy consecutive patients younger than 71 years without diabetes who required an upper arm graft between January 1997 and January 2002 and without previous access in the same limb were randomly allocated to receive either a 6-mm graft or 6- to 8-mm graft. Graft flow was measured every 3 months with the Doppler dilution technique. When access flow was less than 600 mL/min, fistulography was performed, and any stenosis was surgically treated with venous outflow replacement. Thrombectomy and associated stenosis treatment in the same stage was performed in all cases immediately after detection of thrombosis. Complication rate, and primary, assisted primary, and secondary patency rates were compared between the two groups with the Student t test and life table analysis. RESULTS Mean access flow was 975 mL/min for 6-mm grafts (range, 600-1500 mL/min; 95% confidence interval [CI], 889-1070), and for 6- to 8-mm grafts was 1397 mL/min (range, 1122-2700 mL/min; 95% CI, 1122-1672). This difference was significant (P <.01). Complication rate was 0.45 episodes per graft-year in 6-mm grafts, and 0.19 episodes per graft-year in 6- to 8-mm grafts (P <.01). At 1, 2, and 3 years, primary patency rates were 62%, 58%, and 44%, respectively, for 6-mm grafts, and 85%, 78%, and 73% for 6- to 8-mm grafts; log-rank comparison between curves was P =.0259. At 1, 2, and 3 years, secondary patency rates were 85%, 85%, and 85%, respectively, for 6-mm grafts, and 90%, 90%, and 90% for 6- to 8-mm grafts; log-rank comparison between curves was not significant, at P =.0603. At 1, 2, and 3 years, assisted primary patency rates were 84%, 79%, and 76%, respectively, for 6-mm grafts, and 90% for 6- to 8-mm grafts; log-rank comparison was P =.0414. CONCLUSIONS The results of this study show an advantage in terms of primary and assisted primary patency rates, and complication rate for upper arm grafts with diameter 6 mm to 8 mm over grafts with 6-mm diameter in a patient population younger than 70 years without diabetes. The finding of a similar secondary patency rate in both groups is probably due to the surveillance program with sequential measurement of access flow and prompt surgical treatment of stenosis. However, we needed twice the number of rescue procedures in 6-mm grafts to achieve a similar patency rate as with large-bore grafts. These study results must be carefully evaluated, taking into consideration the small number of patients and the selected patient population.
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Affiliation(s)
- Jose R Polo
- Vascular Access Unit, Hospital General Universitario Gregorio Maraņón, Madrid, Spain.
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Abstract
The National Kidney Foundation Dialysis Outcomes Quality Initiative Clinical Practice Guidelines for Vascular Access (DOQI) have defined the access-related care for patients with end-stage renal disease (ESRD). However, the standard of care across the country has fallen short of the DOQI targets. One potential explanation for these shortcomings is the lack of compelling evidence in the literature to support the recommendations. This study was designed to compare the DOQI with the best available evidence in the literature for four clinical questions relevant to the hemodialysis access surgeon: the choice of access type (autogenous versus prosthetic), the type of prosthetic graft, management of the "failing" (nonthrombosed) access, and management of the thrombosed access. The electronic literature databases MEDLINE and Evidence-Based Medicine Reviews were searched and relevant randomized controlled trials or meta-analyses were identified for review. No randomized controlled trials comparing autogenous to prosthetic accesses were identified. However, a recent systematic review reported that the patency rates for upper extremity autogenous accesses were superior to their polytetrafluoroethylene (PTFE) counterparts. The identified randomized trials suggested that the patency rates for the different types of commercially available prosthetic grafts used for access appear comparable. They suggested that standard wall PTFE thickness and prosthetic anastomotic cuffs may be associated with better graft patency, while venous cuffs may be associated with worse patency. Furthermore, the trials suggested percutaneous angioplasty of "failing" prosthetic accesses with greater than 50% stenoses did not appear to improve patency and that routine use of intraluminal stents, as an adjunct to angioplasty, was not beneficial. They did suggest that patency after open surgical revision of "failing" prosthetic accesses was superior to that after percutaneous angioplasty. Lastly, the identified trials suggested that the patency rates after open surgical revision of thrombosed prosthetic accesses was better than after endovascular treatment. Despite the magnitude of hemodialysis-related access problems, the quality of the evidence supporting the clinical decisions relevant to the access surgeon is limited and further clinical trials are justified.
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Affiliation(s)
- Thomas S Huber
- Department of Surgery, University of Flordia College of Medicine, Gainesville, Florida, USA.
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Affiliation(s)
- John J Ricotta
- Department of Surgery, State University of New York at Stony Brook, Room 020, University Hospital, Stony Brook, NY 11794, USA
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Abstract
Since the initial description of the arteriovenous (AV) fistula, autogenous access has been the procedure of choice for chronic hemodialysis. Recently established National Kidney Foundation Dialysis Outcome and Quality Initiative guidelines have validated the superiority of arteriovenous fistulas over AV grafts but have also addressed the fact that a significant percentage of the growing dialysis population does not have veins suitable for primary AV fistulas. Recent advances in forearm, upper arm, and femoral venous transpositions have facilitated the performance of increased numbers of autogenous access procedures. Nevertheless, substantial numbers of patients on chronic hemodialysis require prosthetic AV grafts. Since early reports describing hemodialysis access using expanded polytetrafluoroethylene, surgical results with prosthetic graft materials have remained suboptimal. Modifications in polytetrafluoroethylene grafts and the recent development of alternative graft materials for hemodialysis access have yielded encouraging early results in efforts to improve patency of AV grafts. We will review currently available graft materials and recent developments in an ongoing effort to improve the results with prosthetic and biologic hemodialysis access conduits.
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Affiliation(s)
- Larry A Scher
- Division of Vascular Surgery, North Shore University Hospital, 300 Community Drive, Manhasset, NY 11030, USA
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Van Tricht I, De Wachter D, Tordoir J, Verdonck P. Hemodynamics in a compliant hydraulic in vitro model of straight versus tapered PTFE arteriovenous graft. J Surg Res 2004; 116:297-304. [PMID: 15013369 DOI: 10.1016/s0022-4804(03)00303-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2003] [Indexed: 10/26/2022]
Abstract
BACKGROUND Hemodialysis patients require a vascular access to deliver sufficient blood flow to the artificial kidney. Of these vascular accesses, 30% are prosthetic (mainly polytetrafluorethylene [PTFE]) graft implants. These grafts are prone to the development of stenosis in the vein due to intimal hyperplasia, subsequently leading to thrombosis and graft failure. AIM We investigated the hemodynamics in a straight and a tapered PTFE-graft and compare the hydrodynamical behavior of both grafts. MATERIALS AND METHODS Two different vascular access geometry models were examined: a 6-mm diameter straight graft and a 4- to 7-mm tapered graft. The grafts were sutured to a compliant silicon model of an artery and vein in a loop configuration. Flow rate varied between 500 and 1500 mL/min. Two conditions were tested: 1). control: mean pressure is 100 mm Hg at the arterial inlet; and 2). low resistance condition: pressure is 20 mm Hg at the venous outlet. Pulse pressure is 60 mm Hg at the arterial inlet for both conditions. Pressure and flow velocity are measured continuously, while flow rate is measured volumetrically. RESULTS The pressure drop at the arterial anastomosis of the tapered graft is three times higher compared to the straight graft model. Intragraft pressure drops are similar in both graft types. Mean pressure and pulse pressure in the graft and vein are decreased in the low resistance condition. Also, the difference between maximum and minimum velocity is smaller in this. CONCLUSIONS No significant differences are noted between the graft geometries: pressure drop over the graft is almost equal. The major difference is the higher pressure drop at the arterial anastomosis of the tapered graft.
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Affiliation(s)
- Ilse Van Tricht
- Hydraulics Laboratory, Institute Biomedical Technology, Ghent University, Ghent, Belgium.
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Barone GW, Lightfoot MM, Kumar GV, Eidt JF. Loop-configured upper-arm hemodialysis graft for the “hostile” arm. J Am Coll Surg 2003; 197:1053-5. [PMID: 14644297 DOI: 10.1016/j.jamcollsurg.2003.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Gary W Barone
- Department of Surgery, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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