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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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Stove C, Kingsmore DB, Stevenson KS, Thomson PC, Nath A, Kasthuri R. The impact of stent-graft sizing on venous stenosis re-intervention and arteriovenous graft patency: Free-floating stent outflow is associated with improved outcomes. J Vasc Access 2024; 25:834-842. [PMID: 36428293 DOI: 10.1177/11297298221137152] [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: 02/17/2024] Open
Abstract
BACKGROUND Early cannulation arteriovenous grafts (ecAVG) for dialysis access are limited by reintervention for venous stenosis (VS) despite their good initial patency. Whilst stent-grafts (SG) have shown promise, the optimal sizing is unclear. Therefore, this study aims to determine if outflow vein diameter, SG diameter or these relative to each other (V:Sr) alters outcomes, and if so, which is more important. METHODS Retrospective analysis was performed of Gore® Acuseal® ecAVGs with VS treated with Gore® Viabahn® SG over a 7-year period. Primary patency (PP), time to thrombosis and functional patency were analysed by SG length/diameter, vein diameter and V:Sr. RESULTS We identified 114 ecAVGs with median follow-up 492 days (IQR 189-770). SG length and diameter did not correlate with PP, however, there was a significant relationship between vein diameter and PP (RR = 0.901 (0.832-0.975), p = 0.01) and between V:Sr and PP (RR = 0.462 (0.255-0.838), x2 = 5.866, p = 0.0015). The optimal V:Sr was ⩾1.4 (i.e. vein diameter at least 40% greater than the stent-graft; or 'free-floating' stent outflow) (RR = 2.759 (1.670-4.558), p < 0.001), translating to a difference in median PP of 252 versus 496 days (IQR: 188-316; 322-670). On multivariate analysis, absolute vein diameter lost significance, whilst V:Sr remained an independently significant predictor of PP (RR = 3.247 (1.560-6.759), p = 0.02). CONCLUSIONS Placement of the SG outflow into a relatively larger segment of vein was associated with a significant increase in PP independent of the absolute vein diameter. This suggests that larger calibre SG which are apposed to the vein wall are not required for optimal primary patency, and indeed should be actively avoided. Instead, a 'free-floating' stent outflow which is undersized relative to the recipient vein (whilst maintaining a minimum anchoring calibre) is recommended where possible. This should be considered during intervention and may require selection of longer devices, where practical, to bring the stent outflow into a larger vein segment. LEVEL OF EVIDENCE Level 3a, Non-randomised controlled cohort/follow-up study.
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Affiliation(s)
- Callum Stove
- Interventional Radiology, Queen Elizabeth University Hospital, Glasgow, UK
| | - David B Kingsmore
- Vascular and Endovascular Surgery, Queen Elizabeth University Hospital, Glasgow, UK
- Renal and Transplant Surgery, Queen Elizabeth University Hospital, Glasgow, UK
| | - Karen S Stevenson
- Renal and Transplant Surgery, Queen Elizabeth University Hospital, Glasgow, UK
| | - Peter C Thomson
- Nephrology, Queen Elizabeth University Hospital, Glasgow, UK
| | - Alex Nath
- Interventional Radiology, Queen Elizabeth University Hospital, Glasgow, UK
| | - Ram Kasthuri
- Interventional Radiology, Queen Elizabeth University Hospital, Glasgow, UK
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Kingsmore D, Edgar B, Stevenson K, Greenlaw N, Aitken E, Jackson A, Thomson P. A practical review of barriers and challenges to a definitive randomised trial of grafts versus fistula. J Vasc Access 2024:11297298241234610. [PMID: 38436199 DOI: 10.1177/11297298241234610] [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: 03/05/2024] Open
Abstract
A definitive randomised controlled trial of arteriovenous fistula (AVF) versus arteriovenous grafts (AVG) has been advocated for more than a decade, but as yet, none has been completed. The aim of this article is to summarise the theoretical barriers, review the difficulties in trial design and practicalities that have thus far prevented this from occurring.
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Affiliation(s)
- David Kingsmore
- Renal Transplant and Vascular Access Surgery, Queen Elizabeth University Hospital, Glasgow, UK
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
- Department of Vascular Surgery, Queen Elizabeth University Hospital, Glasgow, UK
| | - Ben Edgar
- Renal Transplant and Vascular Access Surgery, Queen Elizabeth University Hospital, Glasgow, UK
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Karen Stevenson
- Renal Transplant and Vascular Access Surgery, Queen Elizabeth University Hospital, Glasgow, UK
| | - Nicola Greenlaw
- Glasgow Clinical Trials Unit, Robertson Centre for Biostatistics, University of Glasgow, Glasgow, UK
| | - Emma Aitken
- Renal Transplant and Vascular Access Surgery, Queen Elizabeth University Hospital, Glasgow, UK
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Andrew Jackson
- Renal Transplant and Vascular Access Surgery, Queen Elizabeth University Hospital, Glasgow, UK
| | - Peter Thomson
- Department of Renal Medicine, Queen Elizabeth University Hospital, Glasgow, UK
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Hoare D, Kingsmore D, Holsgrove M, Russell E, Kirimi MT, Czyzewski J, Mirzai N, Kennedy S, Neale SL, Mercer JR. Realtime monitoring of thrombus formation in vivo using a self-reporting vascular access graft. COMMUNICATIONS MEDICINE 2024; 4:15. [PMID: 38316912 PMCID: PMC10844314 DOI: 10.1038/s43856-024-00436-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 01/10/2024] [Indexed: 02/07/2024] Open
Abstract
BACKGROUND Chronic kidney disease (CKD) affects 10% of the global population costing over a hundred billion dollars per annum and leading to increased risk of cardiovascular disease. Many patients with CKD require regular haemodialyses. Synthetic arteriovenous grafts (AVG) are increasingly used to provide rapid vascular connection for dialysis. Initially, they have excellent patency rates but are critically limited by neointimal hyperplasia at the venous anastomosis, which drives subsequent thrombosis, graft failure and death. METHODS Here, we describe a system in which electrical impedance spectroscopy sensors are incorporated circumferentially into the wall of a synthetic arteriovenous graft. This is combined with an implantable radiotelemetry system for data transmission outside the patient. The system was tested using monolayers of endothelial and smooth muscle cells as well as swine blood and clots with explanted human carotid artery plaques. Sensor testing was then performed in vitro and the device was implanted in vivo in female swine. RESULTS The device can wirelessly report the accumulation of biological material, both cells and blood. Differences are also detected when comparing controls with pathological atheroma. In swine differences between blockage formation in a graft were remotely obtained and wireless reported. CONCLUSIONS Combining electrical impedance spectroscopy and an implantable radiotelemetry system enables graft surveillance. This has the potential to be used for early detection of venous stenosis and blood clot formation in real-time in vivo. In principle, the concept could apply to other cardiovascular diseases and vascular implantable devices.
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Affiliation(s)
- Daniel Hoare
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, UK
| | - David Kingsmore
- Queen Elizabeth University Hospital, University of Glasgow, Glasgow, UK
| | - Michael Holsgrove
- Bioelectronics Unit, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Ewan Russell
- Bioelectronics Unit, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Mahmut T Kirimi
- Queen Elizabeth University Hospital, University of Glasgow, Glasgow, UK
| | - Jakub Czyzewski
- Bioelectronics Unit, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Nosrat Mirzai
- Bioelectronics Unit, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Simon Kennedy
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, UK
| | - Steven L Neale
- Centre for Medical and Industrial Ultrasonics, James Watt School of Engineering, University of Glasgow, Glasgow, UK
| | - John R Mercer
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, UK.
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