Arteriovenous Fistula Stenosis Research Articles

Inhibition of Lysyl Oxidase with β-aminopropionitrile Improves Venous Adaptation after Arteriovenous Fistula Creation.

The arteriovenous fistula (AVF) is the preferred hemodialysis access for end-stage renal disease (ESRD) patients. Yet, establishment of a functional AVF presents a challenge, even for the most experienced surgeons, since postoperative stenosis frequently occludes the AVF. Stenosis results from the loss of compliance in fibrotic areas of the fistula which turns intimal hyperplasia into an occlusive feature. Fibrotic remodeling depends on deposition and crosslinking of collagen by lysyl oxidase (LOX), an enzyme that catalyzes the deamination of lysine and hydroxylysine residues, facilitating intra/intermolecular covalent bonds. We postulate that pharmacological inhibition of lysyl oxidase (LOX) increases postoperative venous compliance and prevents stenosis in a rat AVF model. LOX gene expression and vascular localization were assayed in rat AVFs and human pre-access veins, respectively. Collagen crosslinking was measured in humans AVFs that matured or failed, and in rat AVFs treated with β-aminopropionitrile (BAPN), an irreversible LOX inhibitor. BAPN was either injected systemically or delivered locally around rat AVFs using nanofiber scaffolds. The major endpoints were AVF blood flow, wall fibrosis, collagen crosslinking, and vascular distensibility. Non-maturation of human AVFs was associated with higher LOX deposition in pre-access veins (N=20, P=0.029), and increased trivalent crosslinks (N=18, P=0.027) in human AVF tissues. Systemic and local inhibition of LOX increased AVF distensibility, while reducing wall fibrosis and collagen crosslinking in rat fistulas. Our results demonstrate that BAPN-mediated inhibition of LOX significantly improves vascular remodeling in experimental fistulas.

Does Static Intra Access Pressure Monitoring of Arteriovenous Fistulas Predicts Intra Access Stenosis?

The initiation of hemodialysis in patients with chronic kidney disease (CKD) requires vascular access formation. The choice of vascular access for individual patient depends on various factors however arteriovenous fistula (AVF) is conventionally considered to be the vascular access of choice. Once hemodialysis is initiated through a mature AVF, there is an ongoing need for surveillance of the AVF to ensure adequate function and prevent vascular access issues among which flow obstruction (both inflow and outflow) remains the most important. AVF stenosis can potentially lead to inadequate dialysis delivery and thrombosis thus leading to access loss. Physical examination and AVF Doppler ultrasonography (DUS) are useful for evaluation of stenosis in the arteriovenous connection and the outflow tract. Periodic assessment of the AVF with Static Intra access Pressure (SIAPR) determination may be a reliable means of predicting vascular access stenosis.
 Material & Methods A cross sectional study carried out at Department of Nephrology, Fatima Memorial Hospital, Lahore from July 2018 to December 2018. In total 113 patients were included, and all patients underwent SIAPR assessment and Doppler Ultrasound of AVF.
 Results Mean age of the patients was 56.81±9.38 years, male to female ratio of the patients was 1.8:1. In this study the SIAPR was suggestive of stenosis in 87(76.99%) patients. The sensitivity, specificity and diagnostic accuracy of SIAPR against Doppler US of the AVF for detection of stenosis was 75.86%, 22.62% & 36.28% respectively
 Conclusion SIAPR has low specificity and diagnostic accuracy compared to Doppler US for detection of AVF stenosis.

Utility of Blood Flow/Resistance Index Ratio (Qx) as a Marker of Stenosis and Future Thrombotic Events in Native Arteriovenous Fistulas.

Objective: The resistance index (RI) and the blood flow volume (Qa) are the most used Doppler ultrasound (DUS) parameters to identify the presence of stenosis in arteriovenous fistula (AVF). However, the reliability of these indexes is now matter of concern, particularly in predicting subsequent thrombosis. In this study, we aimed at testing the diagnostic capacity of the Qa/RI ratio (Qx) for the early identification of AVF stenosis and for thrombosis risk stratification.Methods: From a multicentre source population of 336 HD patients, we identified 119 patients presenting at least one “alarm sign” for clinical suspicious of stenosis. Patients were therefore categorized by DUS as stenotic (n = 60) or not-stenotic (n = 59) and prospectively followed. Qa, RI, and QX, together with various clinical and laboratory parameters, were recorded.Results: Qa and Qx were significantly higher while RI was significantly lower in non-stenotic vs. stenotic patients (p < 0.001 for each comparison). At ROC analyses, Qx had the best discriminatory power in identifying the presence of stenosis as compared to Qa and RI (AUCs 0.976 vs. 0.953 and 0.804; p = 0.037 and p < 0.0001, respectively). During follow-up, we registered 30 thrombotic events with an incidence rate of 12.65 (95% CI 8.54–18.06) per 100 patients/year. In Cox-regression proportional hazard models, Qx showed a better capacity to predict thrombosis occurrence as compared to Qa (difference between c-indexes: 0.012; 95% CI 0.004–0.01).Conclusions: In chronic haemodialysis patients, Qx might represent a more reliable and valid indicator for the early identification of stenotic AVFs and for predicting the risk of following thrombosis.

A Multicenter Global Registry of Paclitaxel Drug-Coated Balloon in Dysfunctional Arteriovenous Fistulae and Grafts: 6-Month Results

PurposeTo assess the safety and clinical benefit of the Lutonix drug-coated balloon (DCB) catheter for the treatment of dysfunctional arteriovenous fistulae (AVF) and grafts (AVG) in a heterogenous real-world population. Materials and MethodsThis multicenter, prospective study enrolled 320 subjects from 12 countries in 25 sites across Europe and Asia. A total of 392 lesions were treated with the Lutonix 035 DCB catheter. Lesions were de novo and restenotic, located in every part of the circuit from the cannulation zone to central venous outflow. In-stent restenotic lesions also were treated. The primary safety endpoint was freedom from serious adverse events involving the access circuit through 30 days. The primary effectiveness endpoint was target lesion primary patency (TLPP) through 6 months. Secondary endpoints included access circuit primary patency (ACPP) at 6 months and the investigation of factors that would independently influence the primary endpoints. ResultsThe primary safety endpoint was 95.5%, while TLPP was 73.9% at 6 months, per Kaplan-Meier survival analysis. ACPP was 71% at 6 months. TLPP for stenosis of AVFs was 78.1%. Subgroup analysis showed significantly improved TLPP when DCB was dilated for ≥120 seconds (P = .007). TLPP was significantly better when predilation occurred compared with cases where only DCB angioplasty was performed (77% vs 48.6%, P = .0005). ConclusionsThe Lutonix AV Global Registry confirms that the Lutonix DCB is a safe and effective treatment option in real-world patients with dysfunctional AVF or AVG. Procedural details had a significant role in TLPP. No significant difference in TLPP was observed among different treatment areas.

Ultrasound appearances and histological correlation of native arteriovenous fistula stenoses - A retrospective case series.

The pathophysiology of haemodialysis arteriovenous fistulae (AVF) stenoses is not fully understood. The aim of this study was to perform histology assessment of stenoses in native AVF and compare and correlate the findings between ultrasound and histology. Intimal medial thickness (IMT) was measured on ultrasound where there was measurable neointimal hyperplasia at the site of stenosis and percentage intimal thickening calculated. Ultrasound findings were then compared with histology analysis of AVF stenoses in nine patients. In this small sample, different sonographic appearances and histology were demonstrated. Ultrasound demonstrated stenoses with neointimal hyperplasia and those with no measurable neointimal hyperplasia. Percentage intimal thickening was between 0% and 100%. The histology of the de novo stenoses (where no previous radiological or surgical procedure was performed) demonstrated stenoses with neointimal hyperplasia, no neointimal hyperplasia and neointimal hyperplasia and fibrosis. The histology findings after percutaneous angioplasty (PTA) demonstrated stenoses with neointimal hyperplasia and fibrosis and a stenosis with an acute inflammatory reaction. The findings in this small sample demonstrated that AVF stenoses are not a uniform group as demonstrated by different sonographic and corresponding appearances at histology. Ultrasound appearances of neointimal hyperplasia appear to correlate with neointimal hyperplasia on histology. These findings warrant further investigation and may have implications for treatment strategies.

Effect of galectin-3 in the pathogenesis of arteriovenous fistula stenosis formation

Objective This study sought to investigate the effect of local expression of galectin-3 in the development of stenotic arteriovenous fistula (AVF). Methods We collected stenotic venous tissues, adjacent nonstenotic venous tissues, and blood samples from end-stage renal disease (ESRD) patients with AVF stenosis, while normal venous tissues and blood samples were collected from ESRD patients before AVF creation as controls. Also blood samples were collected from ESRD patients with nonstenosis functional AVF. Galectin-3, proliferating cell nuclear antigen (PCNA), matrix metalloproteinase-9 (MMP-9), and α-SMA expression in the venous tissues were examined by immunohistochemistry, and the ERK1/2 pathway activity in the intima was accessed by western blot. Serum galectin-3 level was measured by ELISA. Thereafter, human pulmonary arterial smooth muscle cells (HPASMCs) were cultured in vitro, and the interaction between Galectin-3 and ERK1/2 pathway in HPASMCs was estimated by western blot. Results ESRD patients with stenotic AVF had a significant higher serum galectin-3 level than normal controls, and patients with non-stenotic functional AVF. The expression levels of galectin-3, phosphorylated ERK1/2, PCNA, MMP-9, and α-SMA in the stenotic venous tissues were higher than that in the normal venous tissues or the adjacent nonstenotic AVF venous tissues. Correlation analysis showed that the expression of galectin-3 of the neointima was positively correlated with PCNA and α-SMA in the stenotic AVF venous tissues. In HPASMCs, galectin-3 can increase the activity of phosphorylated ERK1/2 and promote the expression of α-SMA. Conclusion In the stenotic AVF of ESRD patients, expression of the galectin-3 was significantly increased, showing a positive relation with neointima development.

Predictors associated with early and late restenosis of arteriovenous fistulas and grafts after percutaneous transluminal angiography

BackgroundThe objective of this study was to assess postintervention patency and analyze the predictive factors associated with early and late restenosis after intervention in hemodialysis arteriovenous fistulas (AVF) and arteriovenous grafts (AVG).MethodsThis study retrospectively analyzed 284 hemodialysis patients who underwent percutaneous transluminal angioplasty (PTA) due to AVF and AVG stenosis. A total of 350 PTA procedures were performed. Clinical, anatomical, biochemical, and technical variables were analyzed. Using univariate and multivariate analyses, we assessed the postintervention patency of PTA by follow-up, and identified the predictive factors taking into account competing risks.ResultsPostintervention patency rates at 3, 6, 12, and 24 months were 86.5%, 66.4%, 42.6%, and 29.8%, respectively, with a median patency duration of 11±0.71 months. Kaplan-Meier analysis showed that the patency rate of the AVF group (n=271) was dramatically higher than the AVG group (n=79) at 3, 6, and 12 months after PTA, respectively (88.9% vs. 78.5%, 69.0% vs. 57.4%, 48.8% vs. 20.0%, P<0.01). Cox survival analysis revealed that the factors associated with postintervention patency of AVF included age of fistulas, serum albumin (ALB) levels, location of stenoses, lesion length longer than 2 cm, multiple stenoses, and maximal pressure of dilatation lower than 16 atm. In addition, factors related to postintervention patency of AVG included the presence of diabetes and hypertension, and serum ALB.ConclusionsThis study demonstrated that the risk factors associated with postintervention patency of AVF included age of fistulas, lower levels of serum ALB, location of stenoses, lesion length longer than 2 cm, multiple stenoses, and maximal pressure of dilatation lower than 16 atm. In addition, risk factors related to postintervention patency of AVG included the presence of diabetes and lower levels of serum ALB, while the presence of hypertension was found to be a protective factor for reducing patency loss of AVG. Among all these factors, serum ALB and multiple stenoses tended to predict early restenosis, while pressure of dilatation tended to predict late restenosis.

Percutaneous transluminal angioplasty as a treatment of stenosis of arteriovenous fistula for hemodialysis

ObjectiveThe aim of our study is to evaluate the endovascular option for treatment of arteriovenous fistula (AVF) stenosis through assessment of success rates and primary patency rate after the angioplasty procedure.BackgroundThe quality of life of hemodialysis patients depends mainly on the patency and proper function of their vascular access. The main cause of AVF dysfunction is stenosis of the fistula. Vascular surgeons should have many surgical and endovascular plans to keep the hemodialysis access patent and functioning. Percutaneous transluminal angioplasty has become an established treatment of dysfunctional AVFs, with many advantages and benefits for the patients.Patients and methodsA prospective study was conducted on 30 patients having end-stage renal disease scheduled for or already on regular hemodialysis with failing or recently failed native AVF during February 2018 till February 2020. Balloon dilation was done alone in 27 cases, whereas it was combined with thrombectomy procedure with a Fogarty catheter in three cases.ResultsA total of 30 patients (19 males and 11 females) were included. Overall, 56.67% of AVFs were brachiocephalic AVF. Radial access was mostly used as an access in 80% of cases, whether percutaneous or surgical. Venous juxta-anastomotic stenosis was the most common site of stenosis (40.91%). Technical success rates in this study reached 86.67%, and the overall primary patency rates were 84.62 and 76.92% at 3 and 6 months, respectively.ConclusionBalloon angioplasty of failing or recently failed native AVF is a safe and effective procedure. It is associated with high success rates, low complication rates, and maintained long-term patency of the hemodialysis access.

Hirudin prevents vascular endothelial cell apoptosis and permeability enhancement induced by the serum from rat with chronic renal failure through inhibiting RhoA/ROCK signaling pathway.

Endothelial cells injury and activation contribute to arteriovenous fistula (AVF) stenosis. Hirudin (Hiru) can inhibit the activity of thrombin, which was reported to enhance endothelial cell permeability and promote vascular inflammatory responses. RhoA/ROCK signaling pathway is also important in regulating vascular endothelial permeability. This study aimed to investigate the role of Hiru on the viability and permeability of human umbilical vein endothelial cells (HUVECs) following stimulation of serum from rat with chronic renal failure (CRF) and illustrated the effects of Hiru on RhoA/ROCK signaling. Wistar rats were randomly divided into control group and CRF group. Serum from each group was collected to stimulate HUVECs. Proliferation capability was estimated with Cell Count Kit-8 (CCK-8) assay. Transwell assay was performed to determine permeability. Cell apoptosis was examined using Tunel staining. Telomere length and telomerase activity were determined by qPCR. Moreover, the expression of RhoA, ROCK1 and ROCK2 was estimated via western blot. Results showed that the serum from CRF rat significantly inhibited cell viability while enhanced cell permeability and apoptosis. Different concentrations of Hiru prevented the above effects caused by CRF serum. Additionally, Hiru recovered the CRF serum-induced decreased telomere length and telomerase activity. Hiru also inhibited the protein expression of RhoA, ROCK1 and ROCK2, which were activated by CRF serum. Moreover, the ROCK inhibitor, Y27632, exhibited similar effects with Hiru. In conclusion, Hiru-restored HUVECs cell viability, telomere length and telomerase activity, suppressed permeability and apoptosis in the presence of CRF serum might depend on inactivating the RhoA/ROCK signaling.

Efficacy of ultrasound-guided percutaneous transluminal angioplasty for arteriovenous fistula stenosis or occlusion at juxta-anastomosis: A 3-year follow-up cohort study

ObjectiveArteriovenous fistula (AVF) is the preferred access for hemodialysis. Percutaneous transluminal angioplasty (PTA) has become a choice for AVF stenosis, and ultrasound has been used in PTA more frequently. MethodsThis single-center retrospective cohort study analyzed 129 patients who underwent PTA in the First Affiliated Hospital of Chongqing Medical University from January 2016 to December 2016. Angioplasty was performed using a noncompliant high-pressure balloon. The process was visualized by duplex scan. Our inclusion criteria were as follows: (1) stenoses or occlusions were located at the juxta-anastomosis site: the first 5 cm of the vein distal to the anastomosis; (2) stenosis was confirmed with the following conditions: (a) flow rates are <500 mL/min in the brachial artery and <200 mL/min in the fistula during dialysis, and (b) the stenosis diameter is <1.7 mm. We used the Kaplan-Meier curve to show the postintervention primary and secondary patency rates of patients with stenosis and occlusion. ResultsAltogether, 129 patients with 76 males were analyzed. Moreover, 104 have AVFs on the left arm, and only one patient had an ulnar-basilic AVF, whereas others had a radial-cephalic AVF. The postintervention primary patency rates are better in occlusion cases (P < .05), whereas secondary patency rates have no difference. The postintervention primary patency rates are better in patients without diabetes mellitus (P < .05), whereas the secondary patency rates had no difference. ConclusionsFor juxta-anastomosis site stenosis or occlusion, PTA can be used to obtain satisfactory results.

Soluble vascular endothelial growth factor receptor-1 as a novel marker of arteriovenous fistula stenosis in hemodialysis patients.

Arteriovenous fistula (AVF) stenosis is one of the most important clinical problems in hemodialysis patients. The histopathological findings of neointimal hyperplasia and impaired angiogenesis have been well established in stenotic AVFs. Soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) has been implicated in pathological angiogenesis. Thus, we aimed to investigate the association between sVEGFR-1 and AVF stenosis in hemodialysis patients. This prospective cohort study included 70 patients with end-stage renal disease. Forty-five patients were included in the final analysis, and the median follow-up period was 36 months. Venous stenosis was detected by physical examination and documented by fistulography. Blood samples were analyzed a day before the fistula operation, and serum levels of sVEGFR-1 were measured. The median sVEGFR-1 level was higher in the stenosis group than in the nonstenosis group (17 pg/mL [89.5%] vs. 5 pg/mL [19.2%], respectively; P < 0.001]. According to body mass index (BMI) categories, obese patients (BMI > 30 kg/m2 ) had the shortest stenosis-free survival (20 months [9.35-30.65]). Multivariate Cox analysis showed that sVEGFR-1, serum creatinine, and parathyroid hormone levels were associated with AVF stenosis risk. Kaplan-Meier survival curves showed that patients with less than the median value of sVEGFR-1 (<6093.07 pg/mL) had longer cumulative stenosis-free survival than patients with sVEGFR-1 levels above the median value (P < 0.001). Increased levels of sVEGFR-1 and obesity were found to be associated with AVF stenosis in hemodialysis patients.

Experimental murine arteriovenous fistula model to study restenosis after transluminal angioplasty.

Percutaneous transluminal angioplasty (PTA) is a very common interventional treatment for treating stenosis in arteriovenous fistula (AVF) used for hemodialysis vascular access. Restenosis occurs after PTA, resulting in vascular lumen loss and a decrease in blood flow. Experimental animal models have been developed to study the pathogenesis of stenosis, but there is no restenosis model after PTA of stenotic AVF in mice. Here, we describe the creation of a murine model of restenosis after angioplasty of a stenosis in an AVF. The murine restenosis model has several advantages, including the rapid development of restenotic lesions in the vessel after angioplasty and the potential to evaluate endovascular and perivascular therapeutics for treating restenosis. The protocol includes a detailed description of the partial nephrectomy procedure to induce chronic kidney disease, the AVF procedure for development of de novo stenosis and the angioplasty treatment associated with progression of restenosis. We monitored the angioplasty-treated vessel for vascular patency and hemodynamic changes for a period of 28 d using ultrasound. Vessels were collected at different time points and processed for histological analysis and immunostaining. This angioplasty model, which can be performed with basic microvascular surgery skills, could be used to identify potential endovascular and perivascular therapies to reduce restenosis after angioplasty procedures.

Evaluation of Hemodialysis Arteriovenous Bruit by Deep Learning.

Physical findings of auscultation cannot be quantified at the arteriovenous fistula examination site during daily dialysis treatment. Consequently, minute changes over time cannot be recorded based only on subjective observations. In this study, we sought to supplement the daily arteriovenous fistula consultation for hemodialysis patients by recording the sounds made by the arteriovenous fistula and evaluating the sounds using deep learning methods to provide an objective index. We sampled arteriovenous fistula auscultation sounds (192 kHz, 24 bits) recorded over 1 min from 20 patients. We also extracted arteriovenous fistula sounds for each heartbeat without environmental sound by using a convolutional neural network (CNN) model, which was made by comparing these sound patterns with 5000 environmental sounds. The extracted single-heartbeat arteriovenous fistula sounds were sent to a spectrogram and scored using a CNN learning model with bidirectional long short-term memory, in which the degree of arteriovenous fistula stenosis was assigned to one of five sound types (i.e., normal, hard, high, intermittent, and whistling). After 100 training epochs, the method exhibited an accuracy rate of 70–93%. According to the receiver operating characteristic (ROC) curve, the area under the ROC curves (AUC) was 0.75–0.92. The analysis of arteriovenous fistula sound using deep learning has the potential to be used as an objective index in daily medical care.

Differences in Transforming Growth Factor-β1/BMP7 Signaling and Venous Fibrosis Contribute to Female Sex Differences in Arteriovenous Fistulas.

BackgroundWomen have decreased hemodialysis arteriovenous fistula (AVF) maturation and patency rates. We determined the mechanisms responsible for the sex‐specific differences in AVF maturation and stenosis formation by performing whole transcriptome RNA sequencing with differential gene expression and pathway analysis, histopathological changes, and in vitro cell culture experiments from male and female smooth muscle cells.Methods and ResultsMice with chronic kidney disease and AVF were used. Outflow veins were evaluated for gene expression, histomorphometric analysis, Doppler ultrasound, immunohistologic analysis, and fibrosis. Primary vascular smooth muscle cells were collected from female and male aorta vessels. In female AVFs, RNA sequencing with real‐time polymerase chain reaction analysis demonstrated a significant decrease in the average gene expression of BMP7 (bone morphogenetic protein 7) and downstream IL17Rb (interleukin 17 receptor b), with increased transforming growth factor‐β1 (Tgf‐β1) and transforming growth factor‐β receptor 1 (Tgfβ‐r1). There was decreased peak velocity, negative vascular remodeling with higher venous fibrosis and an increase in synthetic vascular smooth muscle cell phenotype, decrease in proliferation, and increase in apoptosis in female outflow veins at day 28. In vitro primary vascular smooth muscle cell experiments performed under hypoxic conditions demonstrated, in female compared with male cells, that there was increased gene expression of Tgf‐β1, Tgfβ‐r1, and Col1 with increased migration.ConclusionsIn female AVFs, there is decreased gene expression of BMP7 and IL17Rb with increased Tgf‐β1 and Tgfβ‐r1, and the cellular and vascular differences result in venous fibrosis with negative vascular remodeling.

Management of dual traumatic arterial-venous fistula from a single shotgun injury: a case report and literature review

BackgroundTraumatic arteriovenous fistula (TAVF) is an uncommon vascular entity that arises in various locations, often from penetrating injuries, with a wide spectrum of signs and symptoms. This case report highlights the importance of suspecting multiple TAVFs after a single gunshot wound, especially if it involves pellets. It also sheds light on adapting treatment, whether endovascular or open repair, to the location and characteristics of each fistula.Case presentationA 35-year-old male, with history of shotgun wound 5 months earlier, presented to our clinic with right lower extremity (RLE) edema and pain. Arterial duplex scan and subsequent angiogram showed two TAVFs at the popliteal and posterior tibial (PT) arteries, both of which could not be exactly localized with a computed tomography angiography (CTA) due to artifacts. The fistula connecting the posterior tibial artery (PTA) and vein was repaired endovascularly using a covered-stent, while the fistula between the popliteal artery and vein was repaired surgically. Postoperative follow-up at 3 months showed no arteriovenous fistula (AVF), patent vessels and distal stent stenosis at the PTA.ConclusionsPatients who sustain gunshot injuries with shrapnel or pellets and develop TAVF consequentially need to be followed up with the possibility of multiple AVFs in mind. Arterial duplex scan is highly sensitive to detect those AVFs, yet angiography remains gold standard, particularly with extensive metal artefacts. Endovascular repair, when feasible, should be considered first, unless the patient is unstable or has anatomical constraints that increase the risk of complications. Lastly, surgeons should be weary of deep venous thrombosis (DVT), the Branham effect and arterial aneurysmal dilation postoperatively.

Evaluation of Percutaneous Transluminal Angioplasty on the Success of Venoplasty in the Management of Hemodialysis Fistula Stenosis

Introduction: Patients with chronic kidney failure whose life depends on routine hemodialysis, need good hemodialysis access. Arteriovenous fistula (AVF) is the best access, but this access is prone to stenosis. The best treatment for the problem of AVF stenosis is by percutaneous transluminal angioplasty (venography /venoplasty). This action has developed in Cipto Mangunkusmo National Hospital since 2013, but there is no data and evaluation of its success. This study was conducted to evaluate the success of venoplasty in the treatment of AVF stenosis. Method: This study used a retrospective cohort study to assess the outcome of percutaneous transluminal angioplasty (venography and venoplasty) actions in AVF stenosis in patients with chronic kidney failure. The study was conducted in the Ward Division of Vascular and Endovascular Surgery, Integrated Heart Center, Cipto Mangunkusumo National Hospital’s medical records installation, and Hermina Depok Hospital from December 2016 to May 2017 by evaluating the demographic characteristics, underlying diseases, venoplasty, and venography assessment results, and ultrasound results. Results: Characteristics of people with chronic kidney disease with AVF stenosis were found mostly in the age group 50-60 years (40.9%). As many as 59% of patients were male, and underlying disease was mainly caused by hypertension (93.9%) and diabetes mellitus (42.4%). We found a significant relationship between age and sex with the size of AVF stenosis from demographic analysis. There was no significant relationship between the underlying disease, the location of AVF stenosis, and the venography’s outcome with the size of AVF stenosis from venography. There was a significant relationship between the location of AVF stenosis and the success of venoplasty. There was a significant increase in the results of the ultrasound examination, which were the draining vein diameter, volume flow, and peak systolic velocity to the results of venoplasty after the procedure or three months after the procedure. Conclusion: There was a significant relationship between age and sex with the size of AVF stenosis that occurred. There was no significant relationship between the underlying disease, the location of AVF stenosis with the size of AVF stenosis from venography. A significant relationship was found between the location of AVF stenosis and the success of venoplasty. There was a significant relationship between the results of the ultrasound examination (diameter draining vein, volume flow, and peak systolic velocity) to the results of venoplasty after the procedure or three months after the procedure. Keywords: arteriovenous fistula stenosis, percutaneous transluminal angioplasty, venoplasty, ultrasound

Endovascular Management of The Failure of Maturation of Native Arterio-Venous Fistula due to Outflow Stenosis for Hemodialysis

Abstract Background: Arteriovenous fistula (AVF) is a significant procedure for patient in need of hemodialysis. Failure of maturation due to stenosis is a challenge that needs further intervention. Endovascular treatment allows salvaging these fistulae. Aim of the work: To identify the anatomical causes of maturation failure and to assess immediate and long-term clinical effects of PTA of non-mature native (AVF) caused by outflow stenosis using currently available endovascular techniques. Materials and Methods: This study was performed on forty patient complaining of stenosis of primary AVF. The mean age is 60.5. Patient were followed-up every two weeks for the first 2 months, then every month for 6 months post-intervention clinically and radiologically. Collected data includes patient's demographics, cause of renal failure, characters of primary AVF, variables of endovascular intervention, primary patency, and recurrence of stenosis. Results: AVF type was either brachiocephalic (57.5%), brachiobasilic (32.5%) or radiocephalic (10.0%). Fistulography revealed peripheral venous stenosis in 18 patient (45.0%), central venous stenosis in 14 patient (35.0%) , and juxta-anastomotic stenosis in 8 patient (20%). Our technical success was achieved in 87.5% of cases; the patency rate was 91.0% in a month , 86.0% in 3 months , and 80.0% in 6 months. Complications were reported in 10 cases. The recurrence was reported in 7 patient (17.5% of cases). Conclusion: Endovascular salvage of failing A-V fistulas with PTA and Stenting is safe and effective. It is associated with high success rates, low complication rates, and rendering the immediate reuse of the failing shunt.

P1320ASSESSMENT OF ARTERIOVENOUS FISTULA DYSFUNCTION WITH ACCESS STENOSIS IN HEMODIALYSIS PATIENTS USING SMART-PHONE VIDEOS

Abstract Background and Aims Vascular access dysfunction is one of the leading causes of morbidity and a major contributor to healthcare costs in hemodialysis (HD) patients. Inexpensive, non-invasive tools for routine assessment of vascular access function are needed. Hemodynamically relevant stenoses in arteriovenous fistulas (AVF) lead to a reduction in access flow rate (Qa) and changes in blood flow patterns in the AVF that may be picked up by palpation and auscultation. We hypothesized that these changes in blood flow patterns can not only be felt and heard but also seen, i.e., that they may be detectable in video recordings done with commercially available smartphones after digital motion augmentation. Methods We studied HD patients with AVF dysfunction requiring balloon angioplasty and/or stenting. One-minute video recordings of the skin above the AVF and Qa measurements were conducted before and after the endovascular intervention. Videos were recorded with an iPhone 6S (Apple Inc., Cupertino, CA, USA). Qa was measured by HVT100 endovascular flowmeter (Transonic Systems Inc., Ithaca, NY, USA). Significant access stenosis was defined as a &amp;gt;50% reduction of luminal diameter. Degree of stenosis was assessed by angiography. Frame-to-frame pixel changes in video images were amplified using “Eulerian Video Magnification” (Massachusetts Institute of Technology, MA, USA; http://people.csail.mit.edu/mrub/evm/#code). The time-domain data were then transformed into the frequency-domain signals. Fifty random 10-second segments were sampled per one-minute video, and the frequency with the lowest magnitude (Fmin) was determined in each sample (example shown in Fig. 1). The average Fmin was then assessed for its association with the degree of AVF stenosis. Results Ninety subjects were studied (Table 1). AVF interventions were successful in all patients. Post-intervention Qa (1638 ± 714 ml/min) was on average 1.23-fold higher than pre-intervention Qa (1373 ± 684 ml/min; P&amp;lt;0.01, paired t-test). Subjects were grouped by degree of stenosis, and the number of subjects in each category is shown in Fig. 1B. Higher degrees of stenosis were associated with greater increases in Qa from before to after the intervention (P&amp;lt;0.01, one-way ANOVA; Fig. 1C). Interestingly, the degree of AVF stenosis was also positively related with the change in Fmin from before to after the intervention (P=0.08, one-way ANOVA; Fig. 1D). Conclusion Simple smartphone video recordings of AVF appear to contain frequency-domain information that correlates with hemodynamic changes caused by AVF stenoses. While the Fmin metric employed in our analysis is not ideal, these results should encourage the quest for other parameters that exhibit higher correlations with vascular access dysfunction. If successful, this would allow commercially-available smartphones to be used as ubiquitous tools for quick, non-invasive, ambulatory surveillance of AVF function, thereby allowing timely referrals and avoidance of emergency interventions.

P1337ENDOVASCULAR REVISION OF ARTERIOVENOUS ANASTOMOSIS BY DOUBLE GUIDE TECHNIQUE

Abstract Background and Aims Juxta-anastomotic stenosis is the most frequent complication of arteriovenous fistula (AVF) for haemodialysis (HD). Treatment options are surgical bypass by creating a more proximal anastomosis or endovascular treatment by angioplasty. The available literature data show equal outcomes in term of secondary patency, but a significantly higher rate of recurrent stenosis for endovascular treatment (0.5 procedure/AVF/year). We describe the results of endovascular treatment by “double guide technique” (DGT) as to Turmel Rodrigues original description, in a series of patients referred to our centre. Method We describe all consecutive patients treated by DGT in the first semester of 2018 because of a de novo occurring juxta-anastomotic stenosis of the arteriovenous fistula for haemodialysis. The procedure was carried out as described by Turmell Rodrigues. In short: by means of a single retrograde access through the outflow vein by a 6 french valved introducer, two guide wire are navigated into both proximal and distal artery. Two consecutive dilatation of the anastomosis area are then performed including first the juxta-anastomotic vein at 6 to 7 mm (mean 6.7mm, ds 0.55), followed by the juxta-anastomotic artery at 4mm (mean 4.1mm, ds 0.33), as show in figures. Follow up was carried out at 1, 3, 6 12 month by clinical examination and ultrasound examination. Prospectively collected data was analyzed retrospectively. Results 25 patients were treated during the first 6 month of 2018 by a single operator. Patients data (mean): age 71years, HD vintage 31month, AVF vintage 31month. AVF distribution were: distal radio-cephalic 32%, proximal radio-cephalic 52%, distal ulnar-basilic 8%, humero-basilic 8%. Mean preoperative AVF blood flow - as measured by duplex ultrasound (US) - was 540ml/min. 32% of AVF have preoperative blood flow &amp;gt;600ml/min but a critical stenosis (&amp;lt;1.9mm of diameter). Mean juxta-anastomotic vein and juxta-anastomotic artery ballon diameter were 6.7mm (ds 0.55) and 4.1mm (ds 0.33) respectively. Overall mean blood flow at 12 month was 830ml/min. During follow up 3 patients required endovascular treatment of some new occurring stenosis, 3 patients were lost to follow up at 12 month, 1 patient died from unrelated reasons. In 52% of patients any other revision was required, while 32% required 1 further angioplasty, 4% 2 further angioplasty and 4% 4 further angioplasty of the target lesion during the following 12 month (recurrence rate: 0.28 procedure/patients/year). Assisted functional patency at 12month was 95%. Conclusion Endovascular treatment of juxta-anastomotic AVF stenosis by the DGT performed quite satisfactorily in our series and showed a low recurrence on the target lesion compared to data from literature. At 12 month the average AVF blood flow was below 1000ml/min. The technical advantage of the DGT consist in the single, small caliber percutaneous access, needed to complete the procedure. A larger series would confirm how this refinement of the technique compares with the improved results we preliminary observed.

P1356PACLITAXEL-COATED BALLOON ANGIOPLASTY FOR STENOSIS OF ARTERIOVENOUS FISTULA IN PATIENTS UNDER HEMODIALYSIS: 18TH MONTH FOLLOW-UP

Abstract Background and Aims The recording of the experience of the use of paclitaxel-coated balloons in patients with End Stage Renal Disease under hemodialysis (HD) exhibiting narrowing in arteriovenous fistulas (AVF). Method 20 patients with ultrasonographically confirmed AVF dysfunction were subjected after angiographic screening to prosthesis with a simple angioplasty balloon, and then a balloon drug gradually released the drug paclitaxel. After the damage was restored (one-day clinic), arteriovenous communication was used immediately. The degree of vascular stenosis, blood flow to it and kt / V before and after recovery were assessed by ultrasound. At the same time, the clinical course of the patient and the vestibule of the vessel were monitored for 18 months. Results In the 20 patients of the study, since the damage was recovered, AVF was immediately treated without any problems. After angioplasty the degree of stenosis of the responsible vessel was statistically significantly reduced from 69.85% to 27.38% (p &amp;lt;0.05). Flow volume increased statistically significantly from 690.47 mils / min to 942.67 mils / min (p &amp;lt;0.05). The kt / v of patients improved from 1.25 to 1.6. During the 18th -month follow-up, the clinical course of the patients was stable, no problems related to vascular access appeared. Restenosis occurred to two patients, one of each received another successful angioplasty. Conclusion Drug-releasing balloons can be a useful therapeutic option for patients with AVF stenosis due to accelerated endothelial hyperplasia. The use of paclitaxel-coated balloons helps reduce the risk of restenosis of arteriovenous anastomoses and is a safe, time consuming, minimal invasive and immediate solution to AVF management.