scholarly journals AV Graft Stenosis

2020 ◽  
Author(s):  
Keyword(s):  
Graft Stenosis ◽  
Av Graft

scholarly journals Treatment of hemodialysis AV graft stenosis: Stents resurgent

2005 ◽  
Vol 67 (2) ◽  
pp. 772-773 ◽  
Author(s):  
John J. White ◽  
William D. Paulson ◽  
Steve J. Schwab
Keyword(s):  
Graft Stenosis ◽  
Av Graft

Turbulent Flow Evaluation of the Venous Needle During Hemodialysis

2005 ◽  
Vol 127 (7) ◽  
pp. 1141-1146 ◽  
Author(s):  
Sunil Unnikrishnan ◽  
Thanh N. Huynh ◽  
B. C. Brott ◽  
Y. Ito ◽  
C. H. Cheng ◽  
...  
Keyword(s):  
Graft Failure ◽  
Venous Anastomosis ◽  
Graft Stenosis ◽  
Graft Flow ◽  
Endothelial Denudation ◽  
Improved Design ◽  
Wall Injury ◽  
Av Graft

Arteriovenous (AV) grafts and fistulas used for hemodialysis frequently develop intimal hyperplasia (IH) at the venous anastomosis of the graft, leading to flow-limiting stenosis, and ultimately to graft failure due to thrombosis. Although the high AV access blood flow has been implicated in the pathogenesis of graft stenosis, the potential role of needle turbulence during hemodialysis is relatively unexplored. High turbulent stresses from the needle jet that reach the venous anastomosis may contribute to endothelial denudation and vessel wall injury. This may trigger the molecular and cellular cascade involving platelet activation and IH, leading to eventual graft failure. In an in-vitro graft/needle model dye injection flow visualization was used for qualitative study of flow patterns, whereas laser Doppler velocimetry was used to compare the levels of turbulence at the venous anastomosis in the presence and absence of a venous needle jet. Considerably higher turbulence was observed downstream of the venous needle, in comparison to graft flow alone without the needle. While turbulent RMS remained around 0.1m∕s for the graft flow alone, turbulent RMS fluctuations downstream of the needle soared to 0.4–0.7m∕s at 2 cm from the tip of the needle and maintained values higher than 0.1m∕s up to 7–8 cm downstream. Turbulent intensities were 5–6 times greater in the presence of the needle, in comparison with graft flow alone. Since hemodialysis patients are exposed to needle turbulence for four hours three times a week, the role of post-venous needle turbulence may be important in the pathogenesis of AV graft complications. A better understanding of the role of needle turbulence in the mechanisms of AV graft failure may lead to improved design of AV grafts and venous needles associated with reduced turbulence, and to pharmacological interventions that attenuate IH and graft failure resulting from turbulence.

Effect of obesity on saphenous graft stenosis in patients with postoperative recurrent angina.

2007 ◽  
Vol 62 (4) ◽  
pp. 397-402 ◽  
Author(s):  
M.T. Selcuk ◽  
H. Selcuk ◽  
O. Maden ◽  
O. Ozeke ◽  
H. Ulupinar ◽  
...  
Keyword(s):  
Graft Stenosis ◽  
Recurrent Angina

Extracellular signal-regulated kinase inhibition prevents venous adaptive remodeling via regulation of Eph-B4

Vascular ◽  
2021 ◽  
pp. 170853812199985
Author(s):  
Yuanyuan Guo ◽  
Fan Zhu ◽  
Xiong Zhang ◽  
Guangmin Wu ◽  
Pinting Fu ◽  
...  
Keyword(s):  
Western Blotting ◽  
Vein Graft ◽  
Artery Bypass ◽  
Bypass Graft ◽  
Graft Loss ◽  
Elastic Fibers ◽  
Sprague Dawley ◽  
Vein Grafts ◽  
Graft Stenosis

Objectives Vein graft adaptation (VGA) is a process that vein as a vascular graft conduits in arterial reconstructive surgery; VGA can lead to postoperative vein graft stenosis (VGS) and complications after coronary artery bypass graft and other peripheral artery bypass surgeries. VGA is characterized by vein graft loss the venous features without exhibiting arterial features; furthermore, the activation of ERK inhibited the maintenance of venous properties of the vein graft. We hypothesized that ERK inhibition can affect vein VGS through regulating the expression of EphB4. Methods Rat vein transplantation model was established using wild-type and EphB4+/− Sprague-Dawley rats. Hematoxylin-eosin, Masson, Verhoeff, actin staining, and immunohistochemistry were applied to observe the structure of the vein grafts. Vascular smooth muscle cells (VSMCs) were isolated from the vein and vein grafts. Western blotting was used to determine the expression of p-ERK1/2 and EphB4, and immunofluorescence was applied to detect the expression and location of EphB4. Cell wound scratch assay and CCK8 assay were used to determine the migration and proliferation of VSMCs. Real-time polymerase chain reaction was used to determine the mRNA expression of EphB4. Results Western blotting in vein sample and vein graft sample detected p-ERK1/2 and ERK1/2 expression in both EphB4+/+ and EphB4+/− rats. The expression of p-ERK was increased in vein graft compared to vein. Immunofluorescence in VSMCs form EphB4+/+ and EphB4+/− rats detected EphB4 expression in both cells, and the expression of EphB4 was increased in VSMCs form EphB4+/+ rats. SCH772984 reduces the proliferation and migration of VSMCs. Inhibition of ERK suppressed the increase of vein graft wall thickness, and the expression of collagen fibers, elastic fibers, and α-actin was decreased. Vein graft from EphB4+/− rats reduces the expression of EphB4, and SCH772984 suppressed the decrease of EphB4 in vivo. Vein graft from EphB4+/− rats increased the expression of EphB4, and SCH772984 suppressed the increase of EphB4 in vivo. Conclusions The inhibition of ERK1/2 suppressed the process of VGS by decreasing the proliferation of VSMCs. The ERK-inhibitor SCH772984 suppressed the level of VGS by extending the time of EphB4 expression during the process of VGA, thus maintaining the venousization of vein graft. The mechanism may be that the inhibitor SCH772984 suppresses the level of VGS by extending the time of EphB4 expression during the process of VGA. Therefore, our research provides a new target of VGS treatment by inhibiting the expression of ERK1/2 through the process of VGA.

Changes in duplex ultrasound parameters during maturation according to arteriovenous access types in incident hemodialysis patients

2021 ◽  
pp. 112972982110052
Author(s):  
Jae Jin Lee ◽  
Sun Ryoung Choi ◽  
Eun Ju Lee ◽  
Ha Youn Yang ◽  
Seon Ha Baek ◽  
...  
Keyword(s):  
Pulsatility Index ◽  
Significant Positive Correlation ◽  
Duplex Ultrasound ◽  
Hemodialysis Patients ◽  
Hemodynamic Parameters ◽  
Positive Correlation ◽  
Arteriovenous Access ◽  
Artery Flow ◽  
Ultrasound Parameters ◽  
Av Graft

Background: Little is known about the changes in hemodynamic parameters during arteriovenous (AV) access maturation using duplex ultrasound according to radiocephalic fistula (RCF), brachiocephalic fistula (BCF), and AV graft (AVG) in incident hemodialysis (HD) patient. The objective of this study was to evaluate changes and differences in brachial artery flow rate (BAFR) and related parameters affecting maturation by duplex ultrasound in incident HD patients according to access type. Methods: This study was an observational study conducted from March 2019 to October 2020. During the study period, 109 incident patients underwent new AV access creation, of which 100 were included in the study. The duplex ultrasound was performed on the day prior to access creation, further, day 1, 2 weeks, and 4 weeks later after access creation in incident HD patients. Results: Among all the patients, 38 (38%) received BCF, while 26 (26%) underwent RCF. Of the patients with AVG, 18 (50%) had a forearm loop AVG. The overall mean age was 62.2 ± 13.8 years (range, 32–89). The BAFR increased about 6.9 times in the RCF, 17.4 times in the BCF, and 19.5 times in the AVG at day 1. The median BAFR measured on day 1 was 580.4 mL/min for RC, 1029.0 mL/min for BC, and 1133.0 mL/min for AVG. Relative to the values measured in week 4, the BAFR on day 1 was 69.5% in RCF, 90.6% in BCF, and 93.9% in AVG. The acceleration decreased most significantly on day 1( p < 0.05). The acceleration time increased significantly on day 1 ( p < 0.05) and beyond during maturation in the RCF and BCF. The BAFR of the RCF had a significantly negative correlation with the pulsatility index. The BAFR of the BCF showed a significantly positive correlation with the systolic and diastolic blood pressure but negatively correlated with pulse rate. The BAFR of the AVG showed a significant positive correlation with the diameter of the outflow vein. Conclusions: There were differences in the clinical and duplex parameters during maturation according to access type. The most dramatic changes of duplex parameters were on the day after AV access creation regardless of AV access types. Though RCF had a lower BAFR rate compared to BCF and AVG, it already had a sufficient BAFR required for adequate HD treatment the day after creation. The BAFR of BCF was not different from that of AVG.

Perivascular Nitric Oxide Delivery to Saphenous Vein Grafts Prevents Graft Stenosis after Coronary Artery Bypass Grafting: A Novel Sheep Model

Cardiology ◽  
2011 ◽  
Vol 118 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Kyomars Abbasi ◽  
Keivan Shalileh ◽  
Maryam Sotudeh Anvari ◽  
Shahram Rabbani ◽  
Abolfazl Mahdanian ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Coronary Artery ◽  
Coronary Artery Bypass Grafting ◽  
Saphenous Vein ◽  
Artery Bypass ◽  
Bypass Grafting ◽  
Sheep Model ◽  
Vein Grafts ◽  
Graft Stenosis ◽  
Nitric Oxide Delivery

Comparison of Experimental and Numerical Simulations of Flow Within an Arterio-Venous Graft

2000 ◽  
Author(s):  
Paul F. Fischer ◽  
Seung Lee ◽  
Francis Loth ◽  
Hisham S. Bassiouny ◽  
Nurullah Arslan
Keyword(s):  
Flow Field ◽  
Steady Flow ◽  
Laser Doppler Anemometry ◽  
Transition To Turbulence ◽  
Flow Conditions ◽  
Venous Graft ◽  
Venous Anastomosis ◽  
Av Graft ◽  
Good Agreement

Abstract This was a study to compare computational and experimental results of flow field inside the venous anastomosis of an arteriovenous (AV) graft. Laser Doppler anemometry (LDA) measurements were conducted inside an upscaled end-to-side graft model under steady flow conditions at Reynolds number 1820 which is representative of the in vivo flow conditions inside a human AV graft. The distribution of the velocity and turbulence intensity was measured at several locations in the plane of the bifurcation. This flow field was simulated using computation fluid dynamics (CFD) and shown to be in good agreement. Under steady flow conditions, the flow field demonstrated an unsteady character (transition to turbulence).

Employing the Sirolimus-Eluting Poly (Propylene Carbonate) Mesh for the Prevention of Arteriovenous Graft Stenosis in Rats

2018 ◽  
Vol 24 (3) ◽  
pp. 269-277 ◽  
Author(s):  
Hourong Sun ◽  
Chuan-Zhen Liu ◽  
Chunxiao Liu ◽  
Mengmeng Tang ◽  
Guangqing Cao ◽  
...  
Keyword(s):  
Propylene Carbonate ◽  
Western Blotting ◽  
Matrix Metalloproteinase 2 ◽  
Nuclear Antigen ◽  
Boyden Chamber ◽  
Blank Group ◽  
Area Index ◽  
Graft Stenosis ◽  
Poly Propylene

Poly (propylene carbonate, PPC) is a new member of the aliphatic polyester family. An outstanding feature of PPC is that it produces mainly water and carbon dioxide when degraded in vivo, causing minimal side effects. This unique property together with excellent biocompatibility and biodegradability makes PPC a promising material for drug delivery. In this study, we explored the effect of the sirolimus (an inhibitor of cell growth)-eluting PPC mesh on graft stenosis and its possible mechanisms in a rat arteriovenous grafting model. The PPC mesh was prepared by electrospinning. A jugular vein to abdominal aortic autograft transplantation model was established in rats. The graft was then treated by wrapping with the drug mesh or the drug-free mesh or left untreated. Four weeks posttransplantation, neointima was measured with hematoxylin and eosin staining, matrix metalloproteinase-2 (MMP-2), and MMP-9, and proliferating cell nuclear antigen (PCNA) in the grafts were assayed by Western blotting and immunohistochemistry, respectively. In vitro rat aortic adventitial fibroblast cell (RAAFC) migration was assessed using the Boyden chamber assay, and phospho-mammalian target of rapamycin (mTOR) levels in RAAFCs were determined by Western blotting. Animals with the drug mesh had an intimal area index of 4.87% ± 0.98%, significantly lower than that of the blank group (14.21% ± 2.56%) or the PPC group (15.03% ± 2.35%, both P < .05). The sirolimus mesh markedly suppressed MMP-2 and MMP-9 expression, decreased PCNA-positive cell numbers, inhibited RAAFC migration, and reduced phospho-mTOR levels. Our data suggest that the sirolimus-eluting PPC mesh might be potentially applied for the management of grafting stenosis.

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