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Tozzi M, De Letter J, Krievins D, Jushinskis J, D'Haeninck A, Rucinskas K, Miglinas M, Baltrunas T, Nauwelaers S, De Vriese AS, Moll F, Vermassen F. First-in-human feasibility study of the aXess graft (aXess-FIH): 6-Month results. J Vasc Access 2024:11297298231220967. [PMID: 38317272 DOI: 10.1177/11297298231220967] [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: 02/07/2024] Open
Abstract
OBJECTIVE The creation of an arteriovenous fistula (AVF) is considered the most effective hemodialysis (HD) vascular access. For patients who are not suitable for AVF, arteriovenous grafts (AVGs) are the best access option for chronic HD. However, conventional AVGs are prone to intimal hyperplasia, stenosis, thrombosis, and infection. Xeltis has developed an AVG as a potential alternative to currently available AVGs based on the concept of endogenous tissue restoration. The results of the first 6-month follow-up are presented here. METHODS The aXess first-in-human (FIH) study [NCT04898153] is a prospective, single-arm, multicenter feasibility study that evaluates the early safety and performance of the aXess Hemodialysis Graft. A total of 20 patients with end-stage renal disease were enrolled across six European investigational sites. RESULTS At 6-months follow-up, all grafts were patent with primary and secondary patency rates were 80% and 100%, respectively. Three patients required a re-intervention to maintain graft patency, while one re-intervention was required to restore patency. One graft thrombosis and zero infections were reported. CONCLUSION The expected advantages of the novel aXess Hemodialysis Graft over conventional AVGs would be evaluated by the analysis on long-term safety and effectiveness during the 5-year follow-up of the currently ongoing trial.
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Affiliation(s)
- Matteo Tozzi
- Vascular Unit, Department of Medicine and Surgery, Insubria University and Research Center, Varese, Italy
| | - Jan De Letter
- Department of Vascular Surgery, AZ-Sint Jan Brugge, Bruges, Belgium
| | | | | | | | - Kestutis Rucinskas
- Department of Cardiology and Angiology, Vilnius University Hospital Santaros Klinikos, Vilnius, Lithuania
| | - Marius Miglinas
- Department of Cardiology and Angiology, Vilnius University Hospital Santaros Klinikos, Vilnius, Lithuania
| | - Tomas Baltrunas
- Department of Cardiology and Angiology, Vilnius University Hospital Santaros Klinikos, Vilnius, Lithuania
| | - Sigi Nauwelaers
- Department of Thoracic and Vascular Surgery, Ziekenhuis Oost-Limburg, Genk, Belgium
| | - An S De Vriese
- Department of Nephrology and Infectious Diseases, AZ-Sint Jan, Brugge, Bruges, Belgium
| | - Frans Moll
- Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Frank Vermassen
- Department of Thoracic and Vascular Surgery, Ghent University Hospital, Ghent, Belgium
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Prather R, Pourmoghadam Y, Fadhli J, Al-Mousily F, Pourmoghadam K. Preliminary in-silico analysis of vascular graft implantation configuration and surface modification. Sci Rep 2023; 13:16539. [PMID: 37783707 PMCID: PMC10545661 DOI: 10.1038/s41598-023-42998-y] [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] [Received: 02/21/2023] [Accepted: 09/18/2023] [Indexed: 10/04/2023] Open
Abstract
Vascular grafts are used to reconstruct congenital cardiac anomalies, redirect flow, and offer vascular access. Donor tissue, synthetic, or more recently tissue-engineered vascular grafts each carry limitations spanning compatibility, availability, durability and cost. Synthetic and tissue-engineered grafts offer the advantage of design optimization using in-silico or in-vitro modeling techniques. We focus on an in-silico parametric study to evaluate implantation configuration alternatives and surface finishing impact of a novel silicon-lined vascular graft. The model consists of a synthetic 3D-generic model of a graft connecting the internal carotid artery to the jugular vein. The flow is assumed unsteady, incompressible, and blood is modeled as a non-Newtonian fluid. A comparison of detached eddy turbulence and laminar modeling to determine the required accuracy needed found mild differences mainly dictated by the roughness level. The conduit walls are modeled as non-compliant and fixed. The shunt configurations considered, are straight and curved with varied surface roughness. Following a grid convergence study, two shunt configurations are analyzed to better understand flow distribution, peak shear locations, stagnation regions and eddy formation. The curved shunt was found to have lower peak and mean wall-shear stress, while resulting in lower flow power system and decreased power loss across the graft. The curved smooth surface shunt shows lower peak and mean wall-shear stress and lower power loss when compared to the straight shunt.
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Affiliation(s)
- Ray Prather
- Department of Biomedical Sciences, University of Central Florida, Orlando, FL, USA
| | - Yashar Pourmoghadam
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA.
| | - Joseph Fadhli
- Department of Biomedical Sciences, University of Central Florida, Orlando, FL, USA
| | - Faris Al-Mousily
- Department of Medicine, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Kamal Pourmoghadam
- Department of Surgery, College of Medicine, University of Central Florida, Orlando, FL, USA
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Hao D, Lin J, Liu R, Pivetti C, Yamashiro K, Schutzman LM, Sageshima J, Kwong M, Bahatyrevich N, Farmer DL, Humphries MD, Lam KS, Panitch A, Wang A. A bio-instructive parylene-based conformal coating suppresses thrombosis and intimal hyperplasia of implantable vascular devices. Bioact Mater 2023; 28:467-479. [PMID: 37408799 PMCID: PMC10318457 DOI: 10.1016/j.bioactmat.2023.06.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/17/2023] [Accepted: 06/19/2023] [Indexed: 07/07/2023] Open
Abstract
Implantable vascular devices are widely used in clinical treatments for various vascular diseases. However, current approved clinical implantable vascular devices generally have high failure rates primarily due to their surface lacking inherent functional endothelium. Here, inspired by the pathological mechanisms of vascular device failure and physiological functions of native endothelium, we developed a new generation of bioactive parylene (poly(p-xylylene))-based conformal coating to address these challenges of the vascular devices. This coating used a polyethylene glycol (PEG) linker to introduce an endothelial progenitor cell (EPC) specific binding ligand LXW7 (cGRGDdvc) onto the vascular devices for preventing platelet adhesion and selectively capturing endogenous EPCs. Also, we confirmed the long-term stability and function of this coating in human serum. Using two vascular disease-related large animal models, a porcine carotid artery interposition model and a porcine carotid artery-jugular vein arteriovenous graft model, we demonstrated that this coating enabled rapid generation of self-renewable "living" endothelium on the blood contacting surface of the expanded polytetrafluoroethylene (ePTFE) grafts after implantation. We expect this easy-to-apply conformal coating will present a promising avenue to engineer surface properties of "off-the-shelf" implantable vascular devices for long-lasting performance in the clinical settings.
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Affiliation(s)
- Dake Hao
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA, 95817, United States
| | - Jonathan Lin
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
| | - Ruiwu Liu
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
| | - Christopher Pivetti
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA, 95817, United States
| | - Kaeli Yamashiro
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
| | - Linda M. Schutzman
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
| | - Junichiro Sageshima
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
| | - Mimmie Kwong
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
| | - Nataliya Bahatyrevich
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
| | - Diana L. Farmer
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA, 95817, United States
| | - Misty D. Humphries
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
| | - Kit S. Lam
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
| | - Alyssa Panitch
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, United States
- Department of Biomedical Engineering, University of California Davis, Davis, CA, 95616, United States
| | - Aijun Wang
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA, 95817, United States
- Department of Biomedical Engineering, University of California Davis, Davis, CA, 95616, United States
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4
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Rosado-Toro JA, Philip RC, Dunn ST, Celdran-Bonafonte D, He Y, Berceli SA, Roy-Chaudhury P, Tubaldi E. Functional analysis of arteriovenous fistulae in non-contrast magnetic resonance images. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 222:106938. [PMID: 35738094 DOI: 10.1016/j.cmpb.2022.106938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 05/09/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND OBJECTIVE Arteriovenous fistulae (AVF) are the preferred mode of hemodialysis vascular access and their successful maturation is critical to reduce patient morbidity, mortality, cost, and improve quality of life. Peri-anastomotic venous segment stenosis is the primary cause of AVF maturation failure. The objective is to develop a software protocol for the functional analysis of arteriovenous fistula. METHOD We have developed a standard protocol for the anatomical analysis of the AVF to better understand the mechanisms involved in AVF stenosis and to identify future imaging biomarkers for AVF success or failure using non-contrast magnetic resonance imaging (MRI). The 3D model of the AVF is created using a polar dynamic programming technique. Analysis has been performed on six Yorkshire cross domestic swine, but techniques can be applied into clinical settings. RESULTS Differences in AVF angles and vein curvature are associated with significant variability of venous cross-sectional area. This suggests that the pattern of stenosis is likely to be dependent upon hemodynamic profiles which are largely determined by AVF anatomical features and could play an important role in AVF maturation. CONCLUSIONS This protocol enables us to visualize and study the hemodynamic profiles indirectly allowing early stratification of patients into high and low risk groups for AVF maturation failure. High risk patients could then be targeted with an enhanced process of care or future maturation enhancing therapies resulting in a much-needed precision-medicine approach to dialysis vascular access.
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Affiliation(s)
| | - Rohit C Philip
- BIO5 Institute, University of Arizona, Tucson, AZ, USA; Department of Electrical and Computer Engineering, College of Engineering, University of Arizona, Tucson, AZ, USA
| | - Samuel Thomas Dunn
- BIO5 Institute, University of Arizona, Tucson, AZ, USA; Department of Aerospace and Mechanical Engineering, College of Engineering, University of Arizona, Tucson, AZ, USA
| | | | - Yong He
- Department of Surgery, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Scott A Berceli
- Department of Surgery, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Prabir Roy-Chaudhury
- UNC Kidney Center, College of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Eleonora Tubaldi
- Department of Mechanical Engineering, University of Maryland, College Park, MD, USA.
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5
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Cakir S, Guzelbey T, Mutlu IN, Kilickesmez O. Comparison of functional patency rates between paclitaxel-eluting versus plain balloon angioplasty in hemodialysis patients with central venous stenosis: An intra-individual comparison study. Ther Apher Dial 2021; 26:185-190. [PMID: 33891365 DOI: 10.1111/1744-9987.13662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 04/07/2021] [Accepted: 04/20/2021] [Indexed: 11/29/2022]
Abstract
Central venous stenosis (CVS) is usually a late-diagnosed clinical entity that is common in hemodialysis patients. It causes various problems ranging from hemodialysis difficulty to loss of the arterio-venous (A-V) fistula. In the present study, we aimed to determine the effect of drug eluting balloon while excluding the influence of other variable factors by evaluating the same individuals with plain and paclitaxel-eluting balloons. This research was a prospective study of 18 symptomatic hemodialysis patients (age 50.9 ± 14.0 years, range 32-72 years; 11 male, 7 female) with CVS who underwent treatment by plain balloon angioplasty (PBA) and paclitaxel-eluting balloon angioplasty (PEBA) in our hospital from January 2016 to June 2017. First, third and sixth month central vein patency rates were compared. The median patency rates of central veins were 109.0 (range: 10-324) days after PBA and 238.5 (range: 157-501) days after PEBA (p < 0.001). There was no statistically significant difference between PBA and PEBA angioplasty in one-month patency (p ˃ 0.05). By contrast, a statistically significant difference was found between 3- and 6-month patency rates (p = 0.031 and p ˂ 0.001, respectively). Kaplan-Meier analysis revealed that the primary cumulative patency rate of PEBA was significantly longer than that of PBA (p ˂ 0.001). In this prospective study, PEBA patency is superior to PBA patency in the treatment of CVS in dialysis patients.
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Affiliation(s)
- Semih Cakir
- Department of Radiology, Istanbul Training and Research Hospital, Istanbul, Turkey
| | - Tevfik Guzelbey
- Department of Radiology, Istanbul Basaksehir Cam and Sakura City Hospital, Istanbul, Turkey
| | - Ilhan N Mutlu
- Department of Radiology, Istanbul Basaksehir Cam and Sakura City Hospital, Istanbul, Turkey
| | - Ozgur Kilickesmez
- Department of Radiology, Istanbul Basaksehir Cam and Sakura City Hospital, Istanbul, Turkey
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6
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De Nisco G, Gallo D, Siciliano K, Tasso P, Lodi Rizzini M, Mazzi V, Calò K, Antonucci M, Morbiducci U. Hemodialysis arterio-venous graft design reducing the hemodynamic risk of vascular access dysfunction. J Biomech 2020; 100:109591. [PMID: 31902610 DOI: 10.1016/j.jbiomech.2019.109591] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/04/2019] [Accepted: 12/18/2019] [Indexed: 11/18/2022]
Abstract
Although arterio-venous grafts (AVGs) represent the second choice as permanent vascular access for hemodialysis, this solution is still affected by a relevant failure rate due to graft thrombosis, and development of neointimal hyperplasia (IH) at the distal vein. As a key role in these processes has been attributed to the abnormal hemodynamics establishing in the distal vein, the optimization of AVGs design aimed at minimizing flow disturbances would reduce AVG hemodynamic-related risks. In this study we used computational fluid dynamics to investigate the impact of alternative AVG designs on the reduction of IH and thrombosis risk at the distal venous anastomosis. The performance of the newly designed AVGs was compared to that of commercially available devices. In detail, a total of eight AVG models in closed-loop configuration were constructed: two models resemble the commercially available straight conventional and helical-shaped AVGs; six models are characterized by the insertion of a flow divider (FD), straight or helical shaped, differently positioned inside the graft. Unfavorable hemodynamic conditions were analyzed by assessing the exposure to disturbed shear at the distal vein. Bulk flow was investigated in terms of helical blood flow features, potential thrombosis risk, and pressure drop over the graft. Findings from this study clearly show that using a helically-shaped FD located at the venous side of the graft could induce beneficial helical flow patterns that, minimizing flow disturbances, reduce the IH-related risk of failure at the distal vein, with a clinically irrelevant increase in thrombosis risk and pressure drop over the graft.
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Affiliation(s)
- Giuseppe De Nisco
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Diego Gallo
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Katia Siciliano
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Paola Tasso
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Maurizio Lodi Rizzini
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Valentina Mazzi
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Karol Calò
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | | | - Umberto Morbiducci
- Polito(BIO)Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy.
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7
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Jia L, Wang L, Wei F, Li C, Wang Z, Yu H, Chen H, Wang B, Jiang A. Effects of Caveolin-1-ERK1/2 pathway on endothelial cells and smooth muscle cells under shear stress. Exp Biol Med (Maywood) 2019; 245:21-33. [PMID: 31810383 DOI: 10.1177/1535370219892574] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Hemodynamic forces have an important role in venous intimal hyperplasia, which is the main cause of arteriovenous fistula dysfunction. Endothelial cells (ECs) constantly exposed to the shear stress of blood flow, converted the mechanical stimuli into intracellular signals, and interacted with the underlying vascular smooth muscle cells (VSMCs). Caveolin-1 is one of the important mechanoreceptors on cytomembrane, which is related to vascular abnormalities. Extracellular signal-regulated kinase1/2 (ERK1/2) pathway is involved in the process of VSMCs proliferation and migration. In the present study, we explore the effects of Caveolin-1-ERK1/2 pathway and uremia toxins on the endothelial cells and VSMCs following shear stress application. Different shear stress was simulated with a ECs/VSMCs cocultured parallel-plate flow chamber system. Low shear stress and oscillating shear stress up-regulated the expression of fibroblast growth factor-4, platelet-derived growth factor-BB, vascular endothelial growth factor-A, ERK1/2 phosphorylation in endothelial cells, and proliferation and migration of VSMCs but down-regulated the Caveolin-1 expression in endothelial cells. Uremia toxin induces the proliferation and migration of VSMCs but not in a Caveolin-1-dependent manner in the static environment. Low shear stress-induced proliferation and migration of VSMCs is inhibited by Caveolin-1 overexpression and ERK1/2 suppression. Shear stress-regulated VSMC proliferation and migration is an endothelial cells-dependent process. Low shear stress and oscillating shear stress exert atherosclerotic influences on endothelial cells and VSMCs. Low shear stress modulated proliferation and migration of VSMCs through Caveolin-1-ERK1/2 pathway, which suggested that Caveolin-1 and ERK1/2 can be used as a new therapeutic target for the treatment of arteriovenous fistula dysfunction.Impact statementVenous intimal hyperplasia is the leading cause of arteriovenous fistula (AVF) dysfunction. This article reports that shear stress-regulated vascular smooth muscle cells (VSMCs) proliferation and migration is an endothelial cell (EC)-dependent process. Low shear stress (LSS) and oscillating shear stress (OSS) exert atherosclerotic influences on the ECs and VSMCs. LSS-induced proliferation and migration of VSMCs is inhibited by Caveolin-1 overexpression and extracellular signal-regulated kinase1/2 (ERK1/2) suppression, which suggested that Caveolin-1 and ERK1/2 can be used as a new therapeutic target for the treatment of AVF dysfunction.
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Affiliation(s)
- Lan Jia
- Department of Kidney Disease and Blood Purification, Institute of Urology & Key Laboratory of Tianjin, The Second Hospital of Tianjin Medical University, Tianjin 300211, China
| | - Lihua Wang
- Department of Kidney Disease and Blood Purification, Institute of Urology & Key Laboratory of Tianjin, The Second Hospital of Tianjin Medical University, Tianjin 300211, China
| | - Fang Wei
- Department of Kidney Disease and Blood Purification, Institute of Urology & Key Laboratory of Tianjin, The Second Hospital of Tianjin Medical University, Tianjin 300211, China
| | - Chen Li
- Department of Orthopedics, Tianjin Hospital, Tianjin 300211, China
| | - Zhe Wang
- Department of Kidney Disease and Blood Purification, Institute of Urology & Key Laboratory of Tianjin, The Second Hospital of Tianjin Medical University, Tianjin 300211, China
| | - Haibo Yu
- Department of Kidney Disease and Blood Purification, Institute of Urology & Key Laboratory of Tianjin, The Second Hospital of Tianjin Medical University, Tianjin 300211, China
| | - Haiyan Chen
- Department of Kidney Disease and Blood Purification, Institute of Urology & Key Laboratory of Tianjin, The Second Hospital of Tianjin Medical University, Tianjin 300211, China
| | - Bo Wang
- Department of Kidney Disease and Blood Purification, Institute of Urology & Key Laboratory of Tianjin, The Second Hospital of Tianjin Medical University, Tianjin 300211, China
| | - Aili Jiang
- Department of Kidney Disease and Blood Purification, Institute of Urology & Key Laboratory of Tianjin, The Second Hospital of Tianjin Medical University, Tianjin 300211, China
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Reduced patency in left-sided arteriovenous grafts in a porcine model. J Vasc Surg 2019; 72:305-317.e6. [PMID: 31699515 DOI: 10.1016/j.jvs.2019.06.221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 06/05/2019] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The porcine arteriovenous graft model is commonly used to study hemodialysis vascular access failure, with most studies using a bilateral, paired-site approach in either the neck or femoral vessels. In humans, left- and right-sided central veins have different anatomy and diameters, and left-sided central vein catheters have worse outcomes. We assessed the effect of laterality on arteriovenous prosthetic graft patency and hypothesized that left-sided carotid-jugular arteriovenous prosthetic grafts have reduced patency in the porcine model. METHODS Arteriovenous polytetrafluoroethylene grafts were placed ipsilaterally or bilaterally in 10 Yorkshire male pigs from the common carotid artery to the internal jugular vein. Ultrasound measurements of blood flow velocities and diameters were assessed before graft placement. Animals were sacrificed at 1 week, 2 weeks, or 3 weeks. Patency was determined clinically; grafts and perianastomotic vessels were excised and analyzed with histology and immunostaining. RESULTS At baseline, left- and right-sided veins and arteries had similar blood flow velocities. Although internal jugular veins had similar diameters at baseline, left-sided carotid arteries had 11% smaller outer diameters (P = .0354). There were 10 left-sided and 8 right-sided polytetrafluoroethylene grafts placed; only 4 of 10 (40%) grafts were patent on the left compared with 7 of 8 (88%) grafts patent on the right (P = .04). Left-sided grafts had increased macrophages at the arterial anastomosis (P = .0007). Left-sided perianastomotic arteries had thicker walls (0.74 vs 0.60 mm; P = .0211) with increased intima-media area (1.14 vs 0.77 mm2; P = .0169) as well as a trend toward 38% smaller luminal diameter (1.6 vs 2.5 mm; P = .0668) and 20% smaller outer diameter (3.0 vs 3.7 mm; P = .0861). Left- and right-sided perianastomotic veins were similar histologically, but left-sided veins had decreased expression of phosphorylated endothelial nitric oxide synthase (P = .0032) and increased numbers of α-actin-positive smooth muscle cells (P = .0022). CONCLUSIONS Left-sided arteriovenous grafts are associated with reduced short-term patency compared with right-sided grafts in the Yorkshire pig preclinical model of arteriovenous prosthetic grafts. Laterality must be considered in planning and interpreting surgical preclinical models.
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9
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Rother U, Müller-Mohnssen H, Lang W, Ludolph I, Arkudas A, Horch RE, Regus S, Meyer A. Wound closure by means of free flap and arteriovenous loop: Development of flap autonomy in the long-term follow-up. Int Wound J 2019; 17:107-116. [PMID: 31668019 PMCID: PMC7949459 DOI: 10.1111/iwj.13239] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/03/2019] [Accepted: 09/15/2019] [Indexed: 01/13/2023] Open
Abstract
Free flaps in combination with arterial reconstruction by means of arteriovenous loops or bypass have, meanwhile, been established as a therapeutic option in defect reconstruction for areas without recipient vessels. Our aim was to analyse the long‐term performance, flap autonomy, and the flap perfusion. Patients receiving this combined reconstruction at a single‐centre institution were included. During follow‐up examination, the patency of arterial reconstruction was investigated by duplex ultrasound. Flap micro‐circulation was assessed by laser Doppler flowmetry and white light tissue spectrometry (O2C) as well as by indocyanine green fluorescence angiography. Twenty‐three patients could be clinically followed up. Duplex ultrasound showed, in four cases, arterial pedicle occlusion in spite of vital flap. Comparison of the O2C perfusion parameters between flaps with occluded pedicles and those with intact inflow showed no significant difference (parameters sO2: P = .82; Flow: P = .31). Similar results were obtained by fluorescence angiography; no significant difference could be detected between both groups (parameters Ingress P = .13; Ingressrate P = .54). Combined vascular reconstruction with free tissue transfer is associated with a good long‐term outcome and wound closure. Even after flap transplantation to areas with critical tissue perfusion, the flap can develop autonomy and thus survive after pedicle occlusion.
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Affiliation(s)
- Ulrich Rother
- Department of Vascular Surgery, University Hospital Erlangen, Friedrich Alexander University Erlangen-Nuernberg FAU, Erlangen, Germany
| | - Helena Müller-Mohnssen
- Department of Vascular Surgery, University Hospital Erlangen, Friedrich Alexander University Erlangen-Nuernberg FAU, Erlangen, Germany
| | - Werner Lang
- Department of Vascular Surgery, University Hospital Erlangen, Friedrich Alexander University Erlangen-Nuernberg FAU, Erlangen, Germany
| | - Ingo Ludolph
- Department of Plastic and Hand Surgery, University Hospital Erlangen, Friedrich Alexander University Erlangen-Nuernberg FAU, Erlangen, Germany
| | - Andreas Arkudas
- Department of Plastic and Hand Surgery, University Hospital Erlangen, Friedrich Alexander University Erlangen-Nuernberg FAU, Erlangen, Germany
| | - Raymund E Horch
- Department of Plastic and Hand Surgery, University Hospital Erlangen, Friedrich Alexander University Erlangen-Nuernberg FAU, Erlangen, Germany
| | - Susanne Regus
- Department of Vascular Surgery, University Hospital Erlangen, Friedrich Alexander University Erlangen-Nuernberg FAU, Erlangen, Germany
| | - Alexander Meyer
- Department of Vascular Surgery, University Hospital Erlangen, Friedrich Alexander University Erlangen-Nuernberg FAU, Erlangen, Germany
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10
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El-Kurdi M, Soletti L, McGrath J, Linhares S, Rousselle S, Greisler H, Edelman E, Schoen FJ. Functional remodeling of an electrospun polydimethylsiloxane-based polyether urethane external vein graft support device in an ovine model. J Biomed Mater Res A 2019; 107:2135-2149. [PMID: 31094084 PMCID: PMC6689261 DOI: 10.1002/jbm.a.36724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/13/2019] [Accepted: 05/07/2019] [Indexed: 11/07/2022]
Abstract
Saphenous vein graft (SVG) failure rates are unacceptably high, and external mechanical support may improve patency. We studied the histologic remodeling of a conformal, electrospun, polydimethylsiloxane-based polyether urethane external support device for SVGs and evaluated graft structural evolution in adult sheep to 2 years. All sheep (N = 19) survived to their intended timepoints, and angiography showed device-treated SVG geometric stability over time (30, 90, 180, 365, or 730 days), with an aggregated graft patency rate of 92%. There was minimal inflammation associated with the device material at all timepoints. By 180 days, treated SVG remodeling was characterized by minimal/nonprogressive intimal hyperplasia; polymer fragmentation and integration; as well as the development of a neointima, and a confluent endothelium. By 1-year, the graft developed a media-like layer by remodeling the neointima, and elastic fibers formed well-defined structures that subtended the neo-medial layer of the remodeled SVG. Immunohistochemistry showed that this neo-media was populated with smooth muscle cells, and the intima was lined with endothelial cells. These data suggest that treated SVGs were structurally remodeled by 180 days, and developed arterial-like features by 1 year, which continued to mature to 2 years. Device-treated SVGs remodeled into arterial-like conduits with stable long-term performance as arterial grafts in adult sheep.
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Affiliation(s)
| | | | | | | | | | - Howard Greisler
- Loyola University, Maywood, IL and Hines VA Hospital, Hines, IL
| | - Elazer Edelman
- Massachusetts Institute of Technology, Cambridge, MA, Harvard Medical School, Boston, MA, Brigham and Women’s Hospital, Boston, MA
| | - Frederick J. Schoen
- Brigham and Women’s Hospital, Boston, MA, and Harvard Medical School, Boston, MA
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11
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Vascular access animal models used in research. Ann Anat 2019; 225:65-75. [DOI: 10.1016/j.aanat.2019.06.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 06/13/2019] [Accepted: 06/13/2019] [Indexed: 12/22/2022]
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12
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Valencia-Rivero KT, Cruz JC, Wagner-Gutierrez N, D’Amore A, Miranda MC, López R, Guerrero A, Wagner W, Sandoval N, Briceño JC. Evaluation of Microscopic Structure−Function Relationships of PEGylated Small Intestinal Submucosa Vascular Grafts for Arteriovenous Connection. ACS APPLIED BIO MATERIALS 2019; 2:3706-3721. [DOI: 10.1021/acsabm.9b00158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Juan C. Cruz
- Biomedical Engineering Department, Universidad de los Andes, Bogotá, Colombia
| | | | - Antonio D’Amore
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- Fondazione RiMED, Palermo, Italy
| | - Maria C. Miranda
- Fundación Cardioinfantil - Cardiovascular Institution, Bogotá, Colombia
| | - Rocío López
- Fundación Santa Fe de Bogotá, Bogotá, Colombia
- School of Medicine, Universidad de los Andes, Bogotá, Colombia
| | - Albert Guerrero
- Fundación Cardioinfantil - Cardiovascular Institution, Bogotá, Colombia
| | - William Wagner
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Néstor Sandoval
- Fundación Cardioinfantil - Cardiovascular Institution, Bogotá, Colombia
| | - Juan C. Briceño
- Biomedical Engineering Department, Universidad de los Andes, Bogotá, Colombia
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13
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Shiu YT, Rotmans JI, Geelhoed WJ, Pike DB, Lee T. Arteriovenous conduits for hemodialysis: how to better modulate the pathophysiological vascular response to optimize vascular access durability. Am J Physiol Renal Physiol 2019; 316:F794-F806. [PMID: 30785348 PMCID: PMC6580244 DOI: 10.1152/ajprenal.00440.2018] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 02/04/2019] [Accepted: 02/17/2019] [Indexed: 12/11/2022] Open
Abstract
Vascular access is the lifeline for patients on hemodialysis. Arteriovenous fistulas (AVFs) are the preferred vascular access, but AVF maturation failure remains a significant clinical problem. Currently, there are no effective therapies available to prevent or treat AVF maturation failure. AVF maturation failure frequently results from venous stenosis at the AVF anastomosis, which is secondary to poor outward vascular remodeling and excessive venous intimal hyperplasia that narrows the AVF lumen. Arteriovenous grafts (AVGs) are the next preferred vascular access when an AVF creation is not possible. AVG failure is primarily the result of venous stenosis at the vein-graft anastomosis, which originates from intimal hyperplasia development. Although there has been advancement in our knowledge of the pathophysiology of AVF maturation and AVG failure, this has not translated into effective therapies for these two important clinical problems. Further work will be required to dissect out the mechanisms of AVF maturation failure and AVG failure to develop more specific therapies. This review highlights the major recent advancements in AVF and AVG biology, reviews major clinical trials, and discusses new areas for future research.
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Affiliation(s)
- Yan-Ting Shiu
- Division of Nephrology, University of Utah , Salt Lake City, Utah
| | - Joris I Rotmans
- Department of Internal Medicine, Leiden University Medical Center , Leiden , The Netherlands
| | - Wouter Jan Geelhoed
- Department of Internal Medicine, Leiden University Medical Center , Leiden , The Netherlands
| | - Daniel B Pike
- Division of Nephrology, University of Utah , Salt Lake City, Utah
| | - Timmy Lee
- Department of Medicine and Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama
- Veterans Affairs Medical Center , Birmingham, Alabama
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14
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Zheng J, Cui J, Meiyan Qing J, Irani Z. Safety and effectiveness of combined scoring balloon and paclitaxel-coated balloon angioplasty for stenosis in the hemodialysis access circuit. Diagn Interv Imaging 2019; 100:31-37. [DOI: 10.1016/j.diii.2018.05.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 04/25/2018] [Accepted: 05/14/2018] [Indexed: 11/28/2022]
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Bai H, Dardik A, Xing Y. Decellularized Carotid Artery Functions as an Arteriovenous Graft. J Surg Res 2018; 234:33-39. [PMID: 30527493 DOI: 10.1016/j.jss.2018.08.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/16/2018] [Accepted: 08/02/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND Prosthetic arteriovenous grafts (AVG) continue to have a high rate of failure in clinical use, yet there is continued clinical demand for them. However, there is no small animal model of AVG to test novel tissue-engineered vascular grafts. We established a new rat arteriovenous graft model to compare the healing of decellularized carotid artery (CA) to autologous CA. MATERIALS AND METHODS The infrarenal vena cava and aorta of Wistar rats were exposed and dissected free below renal artery. A longitudinal 1 mm venotomy and arteriotomy were made on the anterior walls. The conduit was either autologous CA or heterologous decellularized CA; a conduit was sewn to the inferior vena cava and aorta in end-to-side fashion. Rats were sacrificed on postoperative day 21 for examination. RESULTS All rats survived without heart failure. Conduits had 100% patency rate (day 21) in both the control and decellularized CA groups (n = 6). Both control and decellularized CA showed similar rates of reendothelialization, inflammatory cell infiltration, and cell turnover. The outflow vein beyond the autologous or decellularized conduits showed similar neointimal thickness and cell turnover. CONCLUSIONS Decellularized CA may be a viable tissue engineering graft for use as an arteriovenous graft for dialysis access. The rat aorta-vena cava graft is a useful model to test new materials including tissue-engineered grafts for use as AVG.
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Affiliation(s)
- Hualong Bai
- Department of Physiology, Basic Medical College of Zhengzhou University, Henan, China; Department of Vascular Surgery, First Affiliated Hospital of Zhengzhou University, Henan, China
| | - Alan Dardik
- The Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, Connecticut; Department of Surgery, Yale University School of Medicine, New Haven, Connecticut; Department of Surgery, VA Connecticut Healthcare System, West Haven, Connecticut.
| | - Ying Xing
- Department of Physiology, Basic Medical College of Zhengzhou University, Henan, China.
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16
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Fischer EIC, Bia D, Valtuille R, Graf S, Galli C, Armentano RL. Vascular access Localization Determines Regional Changes in Arterial Stiffness. J Vasc Access 2018; 10:192-8. [DOI: 10.1177/112972980901000310] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background Vascular access (VA) dysfunction is a common cause of hospitalization in chronically hemodialyzed patients (CHP) limiting the improvement in health and has been largely studied in order to decrease the morbidity events that involves both the artery and the vein used in the construction of the fistula. In parallel, patients in end-stage renal failure show an increase in arterial stiffness. Aim The aims of this work were: (a) to evaluate arterial stiffness through pulse wave velocity (PWV) measurements in the carotid-brachial pathway where the arteriovenous fistulae (AVF) was constructed, and (b) to determine possible differences in arterial stiffness between the carotid-brachial pathway with and without VA. Methods PWV, clinical and biochemical parameters were measured in 38 CHP. PWV was obtained in the carotid-femoral, and in the left and right carotid-brachial pathway. Results Carotid-brachial PWV determination in upper limbs with AVF (10.07 ± 2.43 m/s) showed significantly lower values than those observed in the contra-lateral arm without VA (11.55 ± 2.27 m/s). Curiously, the PWV value observed in arms with an AVF was significantly lower in diabetic than in non-diabetic hemodialyzed patients (NDHP) (8.00 ± 2.86 m/s and 10.38 ± 2.33 m/s; respectively). Measurements of PWV in the carotid-femoral pathway in CHP showed a mean value of 14.09 ± 3.12 m/s. Carotid-femoral PWV in NDHP (14.06 ± 2.44 m/s) was significantly lower than that observed in the diabetic patients (16.87 ± 3.42 m/s). Conclusions Carotid-brachial PWV values obtained in the upper limbs, in which VAs were constructed, were significantly lower than that measured in intact arteries in the contra-lateral pathway in CHP.
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Affiliation(s)
- Edmundo I. Cabrera Fischer
- Favaloro University, Buenos Aires - Argentina
- National Council of Scientific and Technical Research (CONICET) - Argentina
| | - Daniel Bia
- Physiology Department, School of Medicine, Republic University, Montevideo - Uruguay
| | - Rodolfo Valtuille
- Technological National University, Buenos Aires - Argentina
- FME Burzaco, Buenos Aires - Argentina
| | - Sebastián Graf
- Favaloro University, Buenos Aires - Argentina
- National Council of Scientific and Technical Research (CONICET) - Argentina
| | - Cintia Galli
- Technological National University, Buenos Aires - Argentina
| | - Ricardo L. Armentano
- Favaloro University, Buenos Aires - Argentina
- Physiology Department, School of Medicine, Republic University, Montevideo - Uruguay
- Technological National University, Buenos Aires - Argentina
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17
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Valencia Rivero KT, Jaramillo Escobar J, Galvis Forero SD, Miranda Saldaña MC, López Panqueva RDP, Sandoval Reyes NF, Briceño Triana JC. New Regenerative Vascular Grafts for Hemodialysis Access: Evaluation of a Preclinical Animal Model. J INVEST SURG 2017; 31:192-200. [DOI: 10.1080/08941939.2017.1303100] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | | | | | | | - Rocío del Pilar López Panqueva
- Department of Biomedical Engineering, Universidad de los Andes, Bogotá, Colombia
- Department of Pathology, Fundacion Santa Fe de Bogota, Bogotá, Colombia
| | - Néstor Fernando Sandoval Reyes
- Department of Congenital Heart Disease and Pediatric Cardiovascular Surgery, Fundacion Cardio Infantil, Bogotá, Colombia
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Heath DE, Cooper SL. The development of polymeric biomaterials inspired by the extracellular matrix. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2017; 28:1051-1069. [DOI: 10.1080/09205063.2017.1297285] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Daniel E. Heath
- Department of Chemical and Biomolecular Engineering, Particulate Fluids Processing Centre, The University of Melbourne, Parkville, Australia
| | - Stuart L. Cooper
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA
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19
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Affiliation(s)
- Daniel E. Heath
- Department of Chemical and Biomolecular Engineering; Particulate Fluids Processing Centre; The University of Melbourne; Parkville Victoria Australia
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20
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Kitrou P, Spiliopoulos S, Karnabatidis D, Katsanos K. Cutting balloons, covered stents and paclitaxel-coated balloons for the treatment of dysfunctional dialysis access. Expert Rev Med Devices 2016; 13:1119-1126. [PMID: 27791450 DOI: 10.1080/17434440.2016.1254548] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Percutaneous transcatheter balloon angioplasty has evolved to the current mainstay treatment for salvage of dysfunctional dialysis access. Nonetheless, it is frequently associated with recurrent vessel restenosis and the need for multiple repeat treatments in order to maintain hemodynamic patency. Cutting-balloons, covered stents or stent-grafts, and paclitaxel-coated balloons have been extensively tested and investigated with the aim to improve immediate anatomical and long-term clinical results. Areas covered: In the present overview, we discuss the background and appraise relevant medical literature on the aforementioned technologies and provide a more in-depth synthesis of the results of different clinical studies for each device category. We will also discuss the limitations in the mode of action of each group of devices and envision what the future holds for the challenging field of dialysis access interventions. Expert commentary: We propose a good practice algorithm for the treatment of thrombosed or dysfunctional dialysis access.
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Affiliation(s)
- Panagiotis Kitrou
- a Department of Interventional Radiology , Patras University Hospital, School of Medicine , Rion , Greece
| | - Stavros Spiliopoulos
- b 2nd Department of Radiology, Interventional Radiology Unit , ATTIKO Athens University Hospital , Athens , Greece
| | - Dimitris Karnabatidis
- a Department of Interventional Radiology , Patras University Hospital, School of Medicine , Rion , Greece
| | - Konstantinos Katsanos
- a Department of Interventional Radiology , Patras University Hospital, School of Medicine , Rion , Greece
- c Department of Interventional Radiology , Guy's and St. Thomas' Hospitals, NHS Foundation Trust, King's Health Partners , London , UK
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21
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Lin PH, Bush RL, Nguyen L, Guerrero MA, Chen C, Lumsden AB. Anastomotic Strategies to Improve Hemodialysis Access Patency—A Review. Vasc Endovascular Surg 2016; 39:135-42. [PMID: 15806274 DOI: 10.1177/153857440503900202] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The number of patients with end-stage renal disease (ESRD) who require maintenance hemodialysis has risen sharply in the past 2 decades. It is estimated that more than 60% of all patients with ESRD who require chronic hemodialysis are accessed through an arteriovenous fistula (AVF) or graft (AVG), and the incidence is increasing at a rate of 2% to 4% per year. The long-term patency rate of an upper extremity AVF or AVG for hemodialysis access remains suboptimal owing in part to progressive stenosis at the venous anastomosis. This article reviews the causative factors of dialysis access-related anastomotic stenosis, or intimal hyperplasia. This article also reviews the clinical experience of various anastomotic strategies to ameliorate the hemodynamic environment in an effort to improve the clinical outcome of hemodialysis access. These strategies include the use of (1) vein cuff at the expanded polytetrafluoroethylene (ePTFE)-venous anastomosis of AVG, (2) cuffed ePTFE dialysis AVG, and (3) anastomotic devices that create an interrupted anastomosis with staples or clips.
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Affiliation(s)
- Peter H Lin
- Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston VAMC (112), 2002 Holcomb Blvd, Houston, TX 77030, USA.
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22
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Lee T, Misra S. New Insights into Dialysis Vascular Access: Molecular Targets in Arteriovenous Fistula and Arteriovenous Graft Failure and Their Potential to Improve Vascular Access Outcomes. Clin J Am Soc Nephrol 2016; 11:1504-1512. [PMID: 27401527 PMCID: PMC4974876 DOI: 10.2215/cjn.02030216] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Vascular access dysfunction remains a major cause of morbidity and mortality in hemodialysis patients. At present there are few effective therapies for this clinical problem. The poor understanding of the pathobiology that leads to arteriovenous fistula (AVF) and graft (AVG) dysfunction remains a critical barrier to development of novel and effective therapies. However, in recent years we have made substantial progress in our understanding of the mechanisms of vascular access dysfunction. This article presents recent advances and new insights into the pathobiology of AVF and AVG dysfunction and highlights potential therapeutic targets to improve vascular access outcomes.
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Affiliation(s)
- Timmy Lee
- Department of Medicine and Division of Nephrology, University of Alabama at Birmingham, Birmingham, Alabama
- Veterans Affairs Medical Center, Birmingham, Alabama; and
| | - Sanjay Misra
- Vascular and Interventional Radiology Translational Laboratory, Department of Radiology, Mayo Clinic, Rochester, Minnesota
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23
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Kwon SH, Li L, He Y, Tey CS, Li H, Zhuplatov I, Kim SJ, Terry CM, Blumenthal DK, Shiu YT, Cheung AK. Prevention of Venous Neointimal Hyperplasia by a Multitarget Receptor Tyrosine Kinase Inhibitor. J Vasc Res 2016; 52:244-256. [PMID: 26788996 DOI: 10.1159/000442977] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 12/01/2015] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND/AIMS Venous neointimal hyperplasia (NH) is the predominant cause of stenosis in hemodialysis arteriovenous grafts (AVG), but there is currently no clinically used therapy to prevent NH. METHODS A porcine AVG model was used to identify potential pharmacological targets to prevent NH. Sunitinib, a broad-spectrum tyrosine kinase inhibitor, was examined as a potential anti-NH drug utilizing in vitro and ex vivo models. RESULTS In an in vivo porcine model, PDGF, VEGF and their receptors PDGFR-α and VEGFR-2 were upregulated at the venous anastomosis within 2 weeks after AVG placement, with NH development by 4 weeks. Sunitinib inhibited PDGF-stimulated proliferation, migration, phosphorylation of MAPK and PI3K/Akt proteins and changes in the expression of cell-cycle regulatory proteins in vascular smooth-muscle cells as well as VEGF-stimulated endothelial cell proliferation in vitro. In an ex vivo model, significant NH was observed in porcine vein segments perfused for 12 days under pathological shear stress. Sunitinib (100 nM) inhibited NH formation, with the intima-to-lumen area ratio decreasing from 0.45 ± 0.25 to 0.04 ± 0.02 (p < 0.05) with treatment. CONCLUSION These findings demonstrate sunitinib to be a potential NH-preventive drug as well as the utility of an ex vivo model to investigate pharmacotherapies under pathophysiological flow conditions.
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Affiliation(s)
- Sun Hyung Kwon
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, U.S.A
| | - Li Li
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A
| | - Yuxia He
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A
| | - Chieh Sheng Tey
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A
| | - Huan Li
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A
| | - Ilya Zhuplatov
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A
| | - Seung-Jung Kim
- School of Medicine, Division of Nephrology, Ewha Womans University, Seoul, South Korea
| | - Christi M Terry
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A
| | - Donald K Blumenthal
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, U.S.A
| | - Yan-Ting Shiu
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A
| | - Alfred K Cheung
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A.,Medical Service, Veterans Affairs Salt Lake City Healthcare System, Salt Lake City, Utah, U.S.A
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24
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Lee T, Haq NU. New Developments in Our Understanding of Neointimal Hyperplasia. Adv Chronic Kidney Dis 2015; 22:431-7. [PMID: 26524947 DOI: 10.1053/j.ackd.2015.06.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 06/26/2015] [Indexed: 12/20/2022]
Abstract
The vascular access remains the lifeline for the hemodialysis patient. The most common etiology of vascular access dysfunction is venous stenosis at the vein-artery anastomosis in arteriovenous fistula and at the vein-graft anastomosis in arteriovenous grafts (AVG). This stenotic lesion is typically characterized on histology as aggressive venous neointimal hyperplasia in both arteriovenous fistula and AVG. In recent years, we have advanced our knowledge and understanding of neointimal hyperplasia in vascular access and begun testing several novel therapies. This article will (1) review recent developments in our understanding of the pathophysiology of neointimal hyperplasia development in AVG and fistula failure, (2) discuss atypical factors leading to neointimal hyperplasia development, (3) highlight key novel therapies that have been evaluated in clinical trials, and (4) discuss future opportunities and challenges to improve our understanding of vascular access dysfunction and translate this knowledge into novel and innovative therapies.
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25
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Massmann A, Fries P, Obst-Gleditsch K, Minko P, Shayesteh-Kheslat R, Buecker A. Paclitaxel-Coated Balloon Angioplasty for Symptomatic Central Vein Restenosis in Patients With Hemodialysis Fistulas. J Endovasc Ther 2015; 22:74-9. [DOI: 10.1177/1526602814566907] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Purpose: To report a retrospective observational analysis of standard balloon angioplasty (BA) vs. paclitaxel-coated balloon angioplasty (PCBA) for symptomatic central vein restenoses in patients with impaired native hemodialysis fistulas. Methods: A retrospective review was conducted of 27 consecutive patients (15 men; mean age 66±13.8 years, range 39–90) with 32 central vein stenoses (CVS; 6 axillary, 11 subclavian, 12 brachiocephalic, and/or 3 superior caval veins) treated successfully using BA. Freedom from reintervention after BA of de novo lesions was 7.4±7.9 months (range 1–24). Twenty-five (92.6%) patients developed symptomatic restenoses and were treated one or more times by BA (n=32) or PCBA (n=20) using custom-made paclitaxel-coated balloons (diameter 6–14 mm). Results: Technical (<30% residual stenosis) and clinical (functional fistula) success rates for the initial and secondary angioplasty procedures were 100%. No minor/major procedure-associated complications occurred. Mean follow-up was 18.4±17.5 months. Kaplan-Meier analysis for freedom from target lesion revascularization (TLR) found PCBA superior to BA (p=0.029). Median freedom from TLR after BA was 5 months; after PCBA, >50% of patients were event-free during the observation period (mean freedom from TLR 10 months). Restenosis intervals were prolonged by PCBA (median 9 months) vs. BA (median 4 months; p=0.023). Conclusion: Paclitaxel-coated balloon angioplasty of central vein restenosis in patients with hemodialysis shunts yields a statistically significant longer freedom from TLR compared to standard balloon angioplasty.
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Affiliation(s)
- Alexander Massmann
- Department of Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg/Saar, Germany
| | - Peter Fries
- Department of Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg/Saar, Germany
| | - Kerstin Obst-Gleditsch
- Department of Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg/Saar, Germany
| | - Peter Minko
- Department of Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg/Saar, Germany
| | - Roushanak Shayesteh-Kheslat
- Department of General, Abdominal, and Vascular Surgery, Saarland University Medical Center, Homburg/Saar, Germany
| | - Arno Buecker
- Department of Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg/Saar, Germany
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26
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Terry CM, Carlson ML, He Y, Ulu A, Morisseau C, Blumenthal DK, Hammock BD, Cheung AK. Aberrant soluble epoxide hydrolase and oxylipin levels in a porcine arteriovenous graft stenosis model. J Vasc Res 2014; 51:269-82. [PMID: 25196102 DOI: 10.1159/000365251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 04/23/2014] [Indexed: 11/19/2022] Open
Abstract
Synthetic arteriovenous grafts (AVGs) used for hemodialysis frequently fail due to the development of neointimal hyperplasia (NH) at the vein-graft anastomosis. Inflammation and smooth-muscle cell (SMC) and myofibroblast proliferation and migration likely play an important role in the pathogenesis of NH. Epoxyeicosatrienoic acids (EETs), the products of the catabolism of arachidonic acid by cytochrome P450 enzymes, possess anti-inflammatory, antiproliferative, antimigratory and vasodilatory properties that should reduce NH. The degradation of vasculoprotective EETs is catalyzed by the enzyme, soluble epoxide hydrolase (sEH). sEH upregulation may thus contribute to NH development by the enhanced removal of vasculoprotective EETs. In this study, sEH, cytochrome P450 and EETs were examined after AVG placement in a porcine model to explore their potential roles in AVG stenosis. Increased sEH protein expression, decreased P450 epoxygenase activity and dysregulation of 5 oxylipin mediators were observed in the graft-venous anastomotic tissues when compared to control veins. Pharmacological inhibitors of sEH decreased the growth factor-induced migration of SMCs and fibroblasts, although they had no significant effect on the proliferation of these cells. These results provide insights on epoxide biology in vascular disorders and a rationale for the development of novel pharmacotherapeutic strategies to prevent AVG failure due to NH and stenosis.
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Affiliation(s)
- Christi M Terry
- Division of Nephrology and Hypertension, University of Utah, Utah, USA
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Major TC, Handa H, Annich GM, Bartlett RH. Development and hemocompatibility testing of nitric oxide releasing polymers using a rabbit model of thrombogenicity. J Biomater Appl 2014; 29:479-501. [PMID: 24934500 DOI: 10.1177/0885328214538866] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Hemocompatibility is the goal for any biomaterial contained in extracorporeal life supporting medical devices. The hallmarks for hemocompatibility include nonthrombogenicity, platelet preservation, and maintained platelet function. Both in vitro and in vivo assays testing for compatibility of the blood/biomaterial interface have been used over the last several decades to ascertain if the biomaterial used in medical tubing and devices will require systemic anticoagulation for viability. Over the last 50 years systemic anticoagulation with heparin has been the gold standard in maintaining effective extracorporeal life supporting. However, the biomaterial that maintains effective ECLS without the use of any systemic anticoagulant has remained elusive. In this review, the in vivo 4-h rabbit thrombogenicity model genesis will be described with emphasis on biomaterials that may require no systemic anticoagulation for extracorporeal life supporting longevity. These novel biomaterials may improve extracorporeal circulation hemocompatibility by preserving near resting physiology of the major blood components, the platelets and monocytes. The rabbit extracorporeal circulation model provides a complete assessment of biomaterial interactions with the intrinsic coagulation players, the circulating platelet and monocytes. This total picture of blood/biomaterial interaction suggests that this rabbit thrombogenicity model could provide a standardization for biomaterial hemocompatibility testing.
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Affiliation(s)
- Terry C Major
- Department of Surgery, University of Michigan Health System, Ann Arbor, USA
| | - Hitesh Handa
- Department of Surgery, University of Michigan Health System, Ann Arbor, USA
| | - Gail M Annich
- Department of Pediatrics, University of Michigan Health System, Ann Arbor, USA
| | - Robert H Bartlett
- Department of Surgery, University of Michigan Health System, Ann Arbor, USA
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Abstract
Despite extensive efforts, most approaches to reduce arteriovenous (AV) access-related complications did not results in substantial improvement of AV access patency thus far. Part of this disappointing progress relates to incomplete understanding of the underlying pathophysiology of hemodialysis access failure. In order to unravel the pathophysiology of hemodialysis access failure, animal models that closely mimic human pathology are of utmost importance. Indeed, it is impossible to study the extremely complex response of the AV access at a molecular and cellular level in great detail in dialysis patients. Over the past decades, numerous animal models have been developed in an attempt to unravel the vascular pathology of AV access failure and to design new therapeutic strategies aimed to improve durability of these vascular conduits. While large animals such as pigs are suitable for intervention studies, murine models have the greatest potential to gain more insight in the molecular mechanisms underlying AV access failure due to the availability of transgenic mice. In the present review, we describe several existing models of AV access failure and discuss the advantages and limitations of these models.
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Kim H, Park S, Kim DJ, Park JS. New Coating Method for Sustained Drug Release: Surface Modification of ePTFE Grafts by inner coating PLGA. B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.5.1333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Arteriovenous fistula stenosis in hemodialysis patients is characterized by an increased adventitial fibrosis. J Nephrol 2014; 27:555-62. [DOI: 10.1007/s40620-014-0050-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 10/07/2013] [Indexed: 02/06/2023]
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Lee T. Novel paradigms for dialysis vascular access: downstream vascular biology--is there a final common pathway? Clin J Am Soc Nephrol 2013; 8:2194-201. [PMID: 23990166 DOI: 10.2215/cjn.03490413] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Vascular access dysfunction is a major cause of morbidity and mortality in hemodialysis patients. The most common cause of vascular access dysfunction is venous stenosis from neointimal hyperplasia within the perianastomotic region of an arteriovenous fistula and at the graft-vein anastomosis of an arteriovenous graft. There have been few, if any, effective treatments for vascular access dysfunction because of the limited understanding of the pathophysiology of venous neointimal hyperplasia formation. This review will (1) describe the histopathologic features of hemodialysis access stenosis; (2) discuss novel concepts in the pathogenesis of neointimal hyperplasia development, focusing on downstream vascular biology; (3) highlight future novel therapies for treating downstream biology; and (4) discuss future research areas to improve our understanding of downstream biology and neointimal hyperplasia development.
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Affiliation(s)
- Timmy Lee
- Department of Internal Medicine, Division of Nephrology and Hypertension, University of Cincinnati, Cincinatti, Ohio;, †Cincinnati Veterans Affairs Medical Center, Cincinnati, Ohio;, ‡Dialysis Vascular Access Research Group, Cincinnati, Ohio, §Department of Medicine, Division of Nephrology, University of Alabama at Birmingham, Birmingham, Alabama
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Zarjou A, Agarwal A. Superoxide in AVF dysfunction: a new target for intervention. Am J Physiol Renal Physiol 2012; 303:F1599-600. [PMID: 23034943 DOI: 10.1152/ajprenal.00549.2012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Roy-Chaudhury P, El-Khatib M, Campos-Naciff B, Wadehra D, Ramani K, Leesar M, Mistry M, Wang Y, Chan JS, Lee T, Munda R. Back to the Future: How Biology and Technology Could Change the Role of PTFE Grafts in Vascular Access Management. Semin Dial 2012; 25:495-504. [DOI: 10.1111/j.1525-139x.2012.01091.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Sanders WG, Morisseau C, Hammock BD, Cheung AK, Terry CM. Soluble epoxide hydrolase expression in a porcine model of arteriovenous graft stenosis and anti-inflammatory effects of a soluble epoxide hydrolase inhibitor. Am J Physiol Cell Physiol 2012; 303:C278-90. [PMID: 22621785 PMCID: PMC3423029 DOI: 10.1152/ajpcell.00386.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 05/21/2012] [Indexed: 01/09/2023]
Abstract
Synthetic arteriovenous (AV) grafts, placed between an artery and vein, are used for hemodialysis but often fail due to stenosis, typically at the vein-graft anastomosis. This study recorded T lymphocyte and macrophage accumulation at the vein-graft anastomosis, suggesting a role for inflammation in stenosis development. Epoxyeicosatrienoic acids (EETs), products of cytochrome P-450 epoxidation of arachidonic acid, have vasculoprotective and anti-inflammatory effects including inhibition of platelet activation, cell migration, and adhesion. EETs are hydrolyzed by soluble epoxide hydrolase (sEH) to less active diols. The effects of a specific inhibitor of sEH (sEHI) on cytokine release from human monocytes and mouse bone marrow-derived macrophages (BMMΦ) from wild-type (WT) and sEH knockout (KO) animals were investigated. Expression of sEH protein increased over time at the anastomosis as evaluated by immunohistochemistry. Pre-exposure of adherent human monocytes to sEHI (5 μM) significantly inhibited lipopolysaccharide-induced release of monocyte chemotactic protein-1 (MCP-1) and tumor necrosis factor-α and enhanced the EET-to-diol ratio. Release of MCP-1 from WT BMMΦ was significantly inhibited but release from sEH KO BMMΦ was not attenuated indicating the specificity of the sEHI. In contrast, sEHI did not inhibit the release of macrophage inflammatory protein-1 or interleukin-6. Nuclear translocation of NF-κB, as assessed by immunocytochemical staining, was not decreased with sEHI in monocytes, but the phosphorylation of JNK was completely abrogated, suggesting this pathway is the target of sEHI effects in monocytes. These results suggest that sEHI may be useful for inhibition of inflammation and subsequently stenosis in AV grafts.
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Affiliation(s)
- William G Sanders
- Department of Pharmaceutics, University of Utah, Salt Lake City, Utah 84112, USA
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Li C, Hill A, Imran M. In vitro and in vivo studies of ePTFE vascular grafts treated with P15 peptide. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 16:875-91. [PMID: 16128294 DOI: 10.1163/1568562054255754] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The purpose of this study is to evaluate the effectiveness of P15 cell-binding peptide treated ePTFE vascular grafts in vitro and in vivo. The P15 peptide was covalently immobilized onto ePTFE vascular grafts by an atmospheric plasma coating method. In vitro cell growth properties were studied using primary human umbilical vein endothelial cells (HUVECs) and primary human umbilical artery smooth muscle cells (HUASMCs). X-ray photoelectron spectroscopy and amino-acid analysis were used to analyze the surface characteristics of the peptide treated and untreated grafts. The cell growth study showed that the P15 peptide effectively promoted the adhesion and proliferation of endothelial cells. 700% more endothelial cells were proliferated on the P15-treated ePTFE grafts compared to the untreated ePTFE controls. In contrast, the P15 peptide was significantly less effective for promoting the adhesion and proliferation of smooth muscle cells than endothelial cells; only about 100% more smooth muscle cells proliferated on the P15-treated samples compared to the untreated control samples. The sheep model was used in the in vivo study. The amount of neointimal hyperplasia present at the arterial and venous sides of the anastomosis and the degree of endothelialization on the luminal surface of the grafts were assessed. Four P15-treated grafts and two control grafts were implanted as arteriovenous grafts between the femoral artery and vein or the carotid artery and jugular vein in two sheep (n = 6). The in vivo study showed that the thickness of the neointimal hyperplasia of untreated grafts was 3-times thicker than that of P15-treated grafts (P < 0.05) at the venous side of the anastomosis. P15-treated grafts also had a higher degree of endothelialization on the graft lumen.
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Affiliation(s)
- Cheng Li
- InCube, Inc., 1390 Willow Road, Menlo Park, CA 94025, USA.
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Lee T, Safdar N, Mistry MJ, Wang Y, Chauhan V, Campos B, Munda R, Cornea V, Roy-Chaudhury P. Preexisting venous calcification prior to dialysis vascular access surgery. Semin Dial 2012; 25:592-5. [PMID: 22452638 DOI: 10.1111/j.1525-139x.2012.01063.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vascular calcification is present in arterial vessels used for dialysis vascular access creation prior to surgical creation. Calcification in the veins used to create a new vascular access has not previously been documented. The objective of this study was to describe the prevalence of venous calcification in samples collected at the time of vascular access creation. Sixty-seven vein samples were studied. A von Kossa stain was performed to quantify calcification. A semi-quantitative scoring system from 0 to 4+ was used to quantify the percentage positive area for calcification as a fraction of total area (0: 0; 1+: 1-10%; 2+: 11-25%; 3+: 26-50%; 4+: >50% positive). Twenty-two of 67 (33%) samples showed evidence of venous calcification. Histologic examination showed varying degrees of calcification within each cell layer. Among the subset of patients with calcification, 4/22 (18%), 19/22 (86%), 22/22 (100%), and 7/22 (32%) had calcification present within the endothelium, intima, media, and adventitia, respectively. The mean semi-quantitative scores of the 22 samples with calcification were 0.18 ± 0.08, 1.2 ± 0.14, 1.6 ± 0.13, and 0.36 ± 0.12 for the endothelium, intima, media, and adventitia, respectively. Our results demonstrate that vascular calcification is present within veins used to create new dialysis vascular access, and located predominately within the neointimal and medial layers.
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Affiliation(s)
- Timmy Lee
- Department of Internal Medicine and Division of Nephrology and Hypertension, University of Cincinnati, Ohio 45267-0585, USA.
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38
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Yuan Y, Duranceau A, Ferraro P, Martin J, Liberman M. Vascular conditioning of the stomach before esophageal reconstruction by gastric interposition. Dis Esophagus 2012; 25:740-9. [PMID: 22292613 DOI: 10.1111/j.1442-2050.2011.01311.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Gastric interposition with intrathoracic or cervical esophagogastrostomy is currently the preferred operation for reconstruction after esophagectomy. Anastomotic leaks however result from poor vascular supply to the proximal stomach. They are responsible for significant morbidity and mortality. 'Ischemic conditioning' of the interposed stomach has been proposed as a technique where the 'delay phenomenon' aims at improving the microcirculation of the gastric conduit and preventing anastomotic leakage. Experimental observations and clinical studies have been conducted to document the immediate effects and results of this approach. The aim of this work is to review the principles, pathophysiology, experimental, and clinical evidence related to vascular conditioning of the stomach prior to esophagectomy with gastric interposition and esophagogastric anastomosis. MEDLINE and PubMed were searched to identify articles related to vascular conditioning of the stomach. Cross references were added and reviewed to complete the reference list. The anatomic basis of ischemic conditioning, the prevalence of ischemic events on the gastric conduit, the methodology to assess the microcirculation before and after gastric devascularization, animal experiments, and clinical studies reported on this approach were reviewed. Ten experimental works, eleven clinical observations, four reviews, and two editorial commentaries addressing ischemic conditioning of the stomach were identified and reviewed. Experimental observations document improved microcirculation to the proximal stomach following partial gastric devascularization. Clinical reports show the feasibility and relative safety of gastric ischemic conditioning. Preliminary observations suggest potential improvements to the gastric microcirculation resulting from gastric ischemic conditioning. This approach may help prevent complications at the esophagogastric anastomosis. The actual level of evidence however cannot promote its use outside of clinical research protocols.
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Affiliation(s)
- Y Yuan
- Department of Surgery, Université de Montréal, Division of Thoracic Surgery, Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
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External Beam Radiation Therapy for PTFE Dialysis Grafts: A Pilot Study. J Vasc Access 2012; 13:329-31. [DOI: 10.5301/jva.5000052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/04/2011] [Indexed: 01/28/2023] Open
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Gessaroli M, Bombardi C, Giunti M, Bacci ML. Prevention of neointimal hyperplasia associated with modified stretch expanded polytetrafluoroethylene hemodialysis grafts (Gore) in an experimental preclinical study in swine. J Vasc Surg 2012; 55:192-202. [DOI: 10.1016/j.jvs.2011.07.076] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 07/15/2011] [Accepted: 07/15/2011] [Indexed: 11/29/2022]
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41
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Corum LE, Hlady V. The effect of upstream platelet-fibrinogen interactions on downstream adhesion and activation. Biomaterials 2011; 33:1255-60. [PMID: 22100981 DOI: 10.1016/j.biomaterials.2011.10.074] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 10/27/2011] [Indexed: 12/15/2022]
Abstract
Circulating activated platelets roll and make transient contacts before ultimately adhering to a substrate. However, despite the dynamic nature of platelet adhesion, most in vitro adhesion and activation studies have focused on establishing local cause and effect relationships. Here, we determined the effect of exposing platelets to immobilized upstream human fibrinogen on downstream adhesion and activation. Microcontact printing was used to prepare substrates that contained well defined fibrinogen priming regions. Washed platelets were perfused over the substrates and adhesion and activation in a downstream capture region were compared with samples that did not contain a fibrinogen priming region. It was found that samples containing an upstream priming region resulted in higher adhesion, platelet spreading areas and aggregation than samples that lacked the priming region. Also, when the priming region was selectively blocked with a polyclonal anti-fibrinogen antibody, the platelet response was attenuated. To characterize this phenomenon further, flow cytometry was used to assess bulk platelet activation following fibrinogen priming. The expression of two activation markers, PAC-1 and P-selectin were quantified. Expression of both activation markers was found to be higher after perfusion over fibrinogen versus albumin-coated substrates.
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Affiliation(s)
- Lindsey E Corum
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA
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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] [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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Forte A, Della Corte A, De Feo M, Cerasuolo F, Cipollaro M. Role of myofibroblasts in vascular remodelling: focus on restenosis and aneurysm. Cardiovasc Res 2010; 88:395-405. [PMID: 20621923 DOI: 10.1093/cvr/cvq224] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Myofibroblasts (MFs) are contractile cells deriving from a multiplicity of resident cells and/or circulating progenitors that are known to play a key role in wound healing. They were first discovered and analysed in the early 1970s in granulation tissue. Since their first identification, the role of MF and their mechanisms of differentiation have been highlighted in a number of diseases, including organ fibrosis and tumours, with particular attention devoted to the liver, kidney, and pulmonary fibrosis. The aim of this review is to summarize the current evidence for the role played by MFs in two frequent vascular diseases related to the remodelling of the vascular wall: the different forms of arterial restenosis and the most common forms of thoracic aortic aneurysm. The in-depth knowledge of the molecular pathways involved in MF differentiation, contraction, and survival/apoptosis could contribute to the identification of novel therapeutic strategies for anti-fibrotic and anti-remodelling therapy of vascular diseases in which these cells are involved.
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Affiliation(s)
- Amalia Forte
- Department of Experimental Medicine, Excellence Research Centre for Cardiovascular Diseases, Second University of Naples, Via L. De Crecchio, 7, 80138 Naples, Italy.
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Lee T, Roy-Chaudhury P. Advances and new frontiers in the pathophysiology of venous neointimal hyperplasia and dialysis access stenosis. Adv Chronic Kidney Dis 2009; 16:329-38. [PMID: 19695501 PMCID: PMC2764321 DOI: 10.1053/j.ackd.2009.06.009] [Citation(s) in RCA: 199] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hemodialysis vascular access dysfunction is a major cause of morbidity and mortality in hemodialysis patients. The most common cause of this vascular access dysfunction is venous stenosis as a result of venous neointimal hyperplasia within the perianastomotic region (arteriovenous fistula) or at the graft-vein anastomosis (polytetrafluoroethylene, or PTFE, grafts). There have been few effective treatments to date for venous neointimal hyperplasia, in part, because of the poor understanding of the pathogenesis of venous neointimal hyperplasia. Therefore, this article will (1) describe the pathology of hemodialysis access stenosis in arteriovenous fistulas and grafts, (2) review and describe both current and novel concepts in the pathogenesis of neointimal hyperplasia formation, (3) discuss current and future novel therapies for treating venous neointimal hyperplasia, and (4) suggest future research areas in the field of hemodialysis vascular access dysfunction.
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Affiliation(s)
- Timmy Lee
- Department of Internal Medicine and Division of Nephrology and Hypertension, University of Cincinnati, Cincinnati, OH 45267-0585, USA.
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Terry CM, Kim SE, Li L, Goodrich KC, Hadley JR, Blumenthal DK, Parker DL, Cheung AK. Longitudinal assessment of hyperplasia using magnetic resonance imaging without contrast in a porcine arteriovenous graft model. Acad Radiol 2009; 16:96-107. [PMID: 19064217 DOI: 10.1016/j.acra.2008.05.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Revised: 05/19/2008] [Accepted: 05/19/2008] [Indexed: 12/25/2022]
Abstract
RATIONALE AND OBJECTIVES Chronic hemodialysis requires a vascular access that provides high blood-flow rates for the extracorporeal recirculation of blood. Synthetic arteriovenous (AV) grafts often fail because of clotting caused by underlying hyperplasia formation. The authors report the use of magnetic resonance (MR) imaging (MRI) without contrast agent to monitor tissue hyperplasia formation as well as luminal area in a porcine model of AV graft stenosis. MATERIALS AND METHODS Expanded reinforced polytetrafluoroethylene grafts were surgically placed between the common carotid artery and the external jugular vein, bilaterally, in pigs. Animals underwent MRI in a 3-T scanner at 3, 4, or 6 weeks after graft placement, followed by euthanasia and the collection of grafts and adjacent tissues for histologic analysis. Two animals underwent sequential scanning at 1, 2, 3, 5, and 7 weeks after graft placement, followed by histologic analysis. RESULTS Measurements of hyperplasia obtained from the MR images were compared with, and correlated well with, measurements obtained from the histologic cross-sections (r = 0.932, P = .02). The MR images provided a more complete view of the venous hyperplasia throughout the graft compared with histology. The MR images could be examined from multiple angles and were unaffected by histologic preparation artifacts. CONCLUSION Unlike histology, MRI provided longitudinal 3-dimensional views of hyperplasia within the AV grafts. This ability of MRI to more completely identify the geometry of hyperplasia and to quantify the tissue volume in vivo could provide benefits over histologic analysis in assessing the pathology of AV graft failure and the efficacy of antihyperplasia interventions.
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Affiliation(s)
- Christi M Terry
- Department of Medicine, Division of Nephrology and Hypertension, University of Utah, Salt Lake City, UT 84112, USA.
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Wu CC, Wen SC, Yang CW, Pu SY, Tsai KC, Chen JW. Plasma ADMA predicts restenosis of arteriovenous fistula. J Am Soc Nephrol 2008; 20:213-22. [PMID: 19118151 DOI: 10.1681/asn.2008050476] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Plasma levels of asymmetrical dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide production, correlate with endothelial dysfunction and the development of cardiovascular events in patients with uremia. It is not known whether endothelial dysfunction contributes to the dysfunction of arteriovenous fistulas (AVFs) in hemodialysis patients. Here, we studied the predictive value of baseline plasma ADMA for symptomatic restenosis of an AVF after percutaneous transluminal angioplasty in dialysis patients. We obtained baseline plasma ADMA levels before percutaneous transluminal angioplasty in 100 consecutive patients with dysfunctional AVFs. Patients were followed up clinically for up to 6 mo after angioplasty for recurrent dysfunction. During the 6 mo after angioplasty, 46 patients experienced recurrent dysfunction of their AVF; of these, follow-up fistulography showed restenosis at the same location in 41, new stenosis at different locations in two, and no significant stenosis in three patients. Up to 60% of the patients with high levels of ADMA (>0.910 microM) had target lesion restenosis compared with 25% of those with low levels (<0.910 microM; P < 0.001). In multivariate analysis, plasma ADMA independently nearly tripled the risk for recurrent symptomatic stenosis of an AVF after percutaneous transluminal angioplasty (hazard ratio 2.65; 95% confidence interval 1.33 to 5.28). These results suggest a role for ADMA in the progression of symptomatic restenoses of AVFs after percutaneous transluminal angioplasty and call for preventive strategies that target ADMA and/or endothelial dysfunction to decrease the risk for AVF restenosis.
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Affiliation(s)
- Chih-Cheng Wu
- Department of Medicine, Taipei Veterans General Hospital, No. 201, Sec.2, Shih-Pai Road, Taipei, Taiwan, Republic of China
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Fetuin-A expression in early venous stenosis formation in a porcine model of hemodialysis graft failure. J Vasc Interv Radiol 2008; 19:1477-82. [PMID: 18693047 DOI: 10.1016/j.jvir.2008.06.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Revised: 06/01/2008] [Accepted: 06/03/2008] [Indexed: 01/16/2023] Open
Abstract
PURPOSE Because fetuin-A is a cytokine with multifunctional effects on vascular smooth muscle cells and fibroblasts, the authors examined the course of its expression in early venous stenosis formation in a porcine model of chronic renal insufficiency with polytetrafluoroethylene (PTFE) arteriovenous (AV) hemodialysis grafts. MATERIALS AND METHODS Pigs had chronic renal insufficiency created by complete embolization of the left kidney and partial embolization of the right kidney. Twenty-eight days later, PTFE AV grafts were placed from the carotid artery to the ipsilateral jugular vein, and the animals were euthanized 3 days (n = 4), 7 days (n = 4), or 14 days (n = 4) later. Expression of fetuin-A was determined by Western blot analysis of the venous stenosis, control veins, and plasma. Immunohistochemical analysis of the venous stenosis and control vein was performed. Blood urea nitrogen (BUN) and creatinine were measured before embolization and at the time of graft placement. RESULTS The mean BUN and creatinine levels at graft placement were significantly higher than before embolization (P < .05). Severe venous neointimal hyperplasia occurred by day 14 and was characterized by primarily alpha-smooth muscle actin-positive cells. By day 14, fetuin-A levels had increased significantly (P < .05) at the venous stenosis compared with control veins and in the serum compared with measurements before embolization. CONCLUSIONS Significantly increased expression of fetuin-A was observed in early venous stenosis by day 14 and in serum compared with baseline measurements. Understanding the role of fetuin-A in venous neointimal hyperplasia could help in improving outcomes in patients undergoing hemodialysis.
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Li L, Terry CM, Shiu YTE, Cheung AK. Neointimal hyperplasia associated with synthetic hemodialysis grafts. Kidney Int 2008; 74:1247-61. [PMID: 18668026 DOI: 10.1038/ki.2008.318] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Stenosis is a major cause of failure of hemodialysis vascular grafts and is primarily caused by neointimal hyperplasia (NH) at the anastomoses. The objective of this article is to provide a scientific review of the biology underlying this disorder and a critical review of the state-of-the-art investigational preventive strategies in order to stimulate further research in this exciting area. The histology of the NH shows myofibroblasts (that are probably derived from adventitial fibroblasts), extracellular matrices, pro-inflammatory cells including foreign-body giant cells, a variety of growth factors and cytokines, and neovasculature. The contributing factors of the pathogenesis of NH include surgical trauma, bioincompatibility of the synthetic graft, and the various mechanical stresses that result from luminal hypertension and compliance mismatch between the vessel wall and graft. These mechanical stimuli are focal in nature and may have a significant influence on the preferential localization of the NH. Novel mechanical graft designs and local drug delivery strategies show promise in animal models in preventing graft NH development. Successful prevention of graft stenosis would provide a superior alternative to the native fistula as hemodialysis vascular access.
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Affiliation(s)
- Li Li
- Department of Medicine, University of Utah, Salt Lake City, Utah, USA
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Misra S, Fu AA, Puggioni A, Karimi KM, Mandrekar JN, Glockner JF, Juncos LA, Anwer B, McGuire AM, Mukhopadhyay D. Increased shear stress with upregulation of VEGF-A and its receptors and MMP-2, MMP-9, and TIMP-1 in venous stenosis of hemodialysis grafts. Am J Physiol Heart Circ Physiol 2008; 294:H2219-30. [PMID: 18326810 DOI: 10.1152/ajpheart.00650.2007] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Venous injury and subsequent venous stenosis formation are responsible for hemodialysis graft failure. Our hypothesis is that these pathological changes are in part related to changes in wall shear stress (WSS) that results in the activation of matrix regulatory proteins causing subsequent venous stenosis formation. In the present study, we examined the serial changes in WSS, blood flow, and luminal vessel area that occur subsequent to the placement of a hemodialysis graft in a porcine model of chronic renal insufficiency. We then determined the corresponding histological, morphometric, and kinetic changes of several matrix regulatory proteins including VEGF-A, its receptors, matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of matrix metalloproteinase (TIMP)-1, and TIMP-2. WSS was estimated by obtaining blood flow and luminal vessel area by performing phase-contrast MRI with magnetic resonance angiography in 21 animals at 1 day after graft placement and prior to death on day 3 (n = 7), day 7 (n = 7), and day 14 (n = 7). At all time points, the mean WSS at the vein-to-graft anastomosis was significantly higher than that at the control vein (P < 0.05). WSS had a bimodal distribution with peaks on days 1 and 7 followed by a significant reduction in WSS by day 14 (P < 0.05 compared with day 7) and a decrease in luminal vessel area compared with control vessels. By day 3, there was a significant increase in VEGF-A and pro-MMP-9 followed by, on day 7, increased pro-MMP-2, active MMP-2, and VEGF receptor (VEGFR)-2 (P < 0.05) and, by day 14, increased VEGFR-1 and TIMP-1 (P < 0.05) at the vein-to-graft anastomosis compared with control vessels. Over time, the neointima thickened and was composed primarily of alpha-smooth muscle actin-positive cells with increased cellular proliferation. Our data suggest that hemodialysis graft placement leads to early increases in WSS, VEGF-A, and pro-MMP-9 followed by subsequent increases in pro-MMP-2, active MMP-2, VEGFR-1, VEGFR-2, and TIMP-1, which may contribute to the development of venous stenosis.
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Affiliation(s)
- Sanjay Misra
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA.
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