Medical adjuvant treatment to increase patency of arteriovenous fistulae and grafts.
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ABSTRACT:
SUBMITTER: Mohamed I
PROVIDER: S-EPMC8406473 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:ObjectiveThe 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.MethodsArteriovenous 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.ResultsAt 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).ConclusionsLeft-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.
| S-EPMC7196525 | biostudies-literature
Project description: Not available
| S-EPMC5435465 | biostudies-literature
Project description:Arteriovenous fistulae (AVF) are the preferred mode of hemodialysis access, but 60% of conventional [vein-to-artery (V-A)] AVF fail to mature, and only 50% remain patent at 1 year. We previously showed improved maturation and patency in a pilot study of the radial artery deviation and reimplantation (RADAR) technique that uses an artery-to-vein (A-V) configuration. Here, we show that RADAR exhibits higher rates of maturation, as well as increased primary and secondary long-term patencies. RADAR is also protective in female patients, where it is associated with decreased reintervention rates and improved secondary patency. RADAR and conventional geometries were compared further in a rat bilateral carotid artery-internal jugular vein fistula model. There was decreased cell proliferation and neointimal hyperplasia in the A-V configuration in male and female animals, but no difference in hypoxia between the A-V and V-A configurations. Similar trends were seen in uremic male rats. The A-V configuration also associated with increased peak systolic velocity and expression of Kruppel-like factor 2 and phosphorylated endothelial nitric oxide synthase, consistent with improved hemodynamics. Computed tomography and ultrasound-informed computational modeling showed different hemodynamics in the A-V and V-A configurations, and improving the hemodynamics in the V-A configuration was protective against neointimal hyperplasia. These findings collectively demonstrate that RADAR is a durable surgical option for patients requiring radial-cephalic AVF for hemodialysis access.
| S-EPMC7705473 | biostudies-literature
Project description:Coronary arteriovenous fistulae are a coronary anomaly, presenting in 0.002% of the general population. Their etiology can be congenital or acquired. We present a review of recent literature related to their epidemiology, etiology, pathophysiology, clinical presentation, diagnostic approach, and therapeutic management.
| S-EPMC4051882 | biostudies-other
Project description:BackgroundAn arteriovenous fistula (AVF) exposes the outflow vein to arterial magnitudes and frequencies of blood pressure and flow, triggering molecular pathways that result in venous remodeling and AVF maturation. It is unknown, however, how venous remodeling, that is lumen dilation and wall thickening, affects venous mechanical properties. We hypothesized that a fistula is more compliant compared with a vein because of altered contributions of collagen and elastin to the mechanical properties.MethodsEphb4+/- and littermate wild-type (WT) male mice were treated with sham surgery or needle puncture to create an abdominal aortocaval fistulae. The thoracic inferior vena cava was harvested 3 wk postoperatively for mechanical testing and histological analyses of collagen and elastin.ResultsMechanical testing of the thoracic inferior vena cava from Ephb4+/- and WT mice showed increased distensibility and increased compliance of downstream veins after AVF compared with sham. Although Ephb4+/- veins were thicker than WT veins at the baseline, after AVF, both Ephb4+/- and WT veins showed similar wall thickness as well as similar collagen and elastin area fractions, but increased collagen undulation compared with sham.ConclusionsFistula-induced remodeling of the outflow vein results in circumferentially increased distensibility and compliance, likely due to post-translational modifications to collagen.
| S-EPMC7054128 | biostudies-literature
Project description:IntroductionArteriovenous fistulae (AVF) are the 'gold standard' vascular access for haemodialysis. Universal usage is limited, however, by a high early failure rate. Several small, single-centre studies have demonstrated better early patency rates for AVF created under regional anaesthesia (RA) compared with local anaesthesia (LA). The mechanistic hypothesis is that the sympathetic blockade associated with RA causes vasodilatation and increased blood flow through the new AVF. Despite this, considerable variation in practice exists in the UK. A high-quality, adequately powered, multicentre randomised controlled trial (RCT) is required to definitively inform practice.Methods and analysisThe Anaesthesia Choice for Creation of Arteriovenous Fistula (ACCess) study is a multicentre, observer-blinded RCT comparing primary radiocephalic/brachiocephalic AVF created under regional versus LA. The primary outcome is primary unassisted AVF patency at 1 year. Access-specific (eg, stenosis/thrombosis), patient-specific (including health-related quality of life) and safety secondary outcomes will be evaluated. Health economic analysis will also be undertaken.Ethics and disseminationThe ACCess study has been approved by the West of Scotland Research and ethics committee number 3 (20/WS/0178). Results will be published in open-access peer-reviewed journals within 12 months of completion of the trial. We will also present our findings at key national and international renal and anaesthetic meetings, and support dissemination of trial outcomes via renal patient groups.Trial registration numberISRCTN14153938.SponsorNHS Greater Glasgow and Clyde GN19RE456, Protocol V.1.3 (8 May 2021), REC/IRAS ID: 290482.
| S-EPMC8704953 | biostudies-literature
Project description:This study characterized the coordinated molecular changes evoked in the structure and composition of the wall of a venous segment exposed to high fistula flow.
2015-07-17 | GSE39488 | GEO
Project description:This study aimed to compare stent graft with balloon tamponade for ruptured dialysis access during percutaneous transluminal angioplasty. Patients over an 8-year period (2010-2018) were identified from a database of 11,609 procedures. The primary endpoint was target lesion primary patency at 12 months. A total of 143 patients who had rupture dialysis access were enrolled, of whom 52 were salvaged by stent grafts and 91 were salvaged by balloon tamponade. The 6-month target lesion primary patency was greater in the stent graft group than in the balloon tamponade group (66.7% vs. 29.5%, P < 0.001). The benefit of stent grafts was sustained for 12 months (52.5% vs. 9.0%, P < 0.001). The stent grafts increased the median time from the index procedure to the next intervention in the ruptured area by 171 days (260 vs. 89 days) at 12 months. There was no significant difference in the access circuit patency rates at 6 months (25.5% vs. 19.8%, P = 0.203) and 12 months (12.0% vs. 5.8%, P = 0.052). The patency results of the stent grafts remained after the multivariable adjustment analysis. Compared to balloon tamponade alone, stent grafts provided superior target lesion primary patency at 6 and 12 months. The access circuit patency rates were similar.
| S-EPMC8741950 | biostudies-literature
Project description:Objective- Arteriovenous fistulae (AVF) are the most common access created for hemodialysis; however, many AVF fail to mature and require repeated intervention, suggesting a need to improve AVF maturation. Eph-B4 (ephrin type-B receptor 4) is the embryonic venous determinant that is functional in adult veins and can regulate AVF maturation. Cav-1 (caveolin-1) is the major scaffolding protein of caveolae-a distinct microdomain that serves as a mechanosensor at the endothelial cell membrane. We hypothesized that Cav-1 function is critical for Eph-B4-mediated AVF maturation. Approach and Results- In a mouse aortocaval fistula model, both Cav-1 mRNA and protein were increased in the AVF compared with control veins. Cav-1 KO (knockout) mice showed increased fistula wall thickening ( P=0.0005) and outward remodeling ( P<0.0001), with increased eNOS (endothelial NO synthase) activity compared with WT (wild type) mice. Ephrin-B2/Fc inhibited AVF outward remodeling in WT mice but not in Cav-1 KO mice and was maintained in Cav-1 RC (Cav-1 endothelial reconstituted) mice (WT, P=0.0001; Cav-1 KO, P=0.7552; Cav-1 RC, P=0.0002). Cavtratin-a Cav-1 scaffolding domain peptide-decreased AVF wall thickness in WT mice and in Eph-B4 het mice compared with vehicle alone (WT, P=0.0235; Eph-B4 het, P=0.0431); cavtratin also increased AVF patency (day 42) in WT mice ( P=0.0275). Conclusions- Endothelial Cav-1 mediates Eph-B4-mediated AVF maturation. The Eph-B4-Cav-1 axis regulates adaptive remodeling during venous adaptation to the fistula environment. Manipulation of Cav-1 function may be a translational strategy to enhance AVF patency.
| S-EPMC6436985 | biostudies-literature
Project description:Coronary artery fistulae are a rare cardiovascular anomaly. Even less common are multiple fistulae involving more than 1 coronary artery. Herein we report the case of a 47-year-old woman who had fistulae from both the right coronary and left circumflex coronary arteries draining into the coronary sinus. These lesions we attempted to close percutaneously but subsequently closed surgically. We discuss diagnostic imaging approaches, along with closure indications, closure options, and outcomes.
| S-EPMC3384048 | biostudies-literature