Arteriovenous Fistula Failure Research Articles

Prognostic factors for radiocephalic arteriovenous fistula maturation in patients with prior placement of a central venous catheter and relationship with inflammation

Aim: A mature and functional arteriovenous fistula (AVF) is considered the best modality for vascular access(VA) for hemodialysis (HD) treatment but the incidence of early failure is high, especially in patients start their HD with a central venous catheter. The aim of this study was to evaluate the prognostic value and association of certain patient characteristics and specific inflammatory markers with early failure of AVF in patients who started their HD therapy with a CVC and a first autogenous radiocephalic AVF (RCAVF) was created after vascular consultation. Material and Methods: A retrospective review of 168 patients with end-stage renal disease who underwent RCAVF creation by the same surgeon by using the same surgical technique and whose primary vascular access for HD treatment was obtained via CVC at the time of access consultation was performed. The patients enrolled into this study were categorized into two groups as Group 1: patients with early failure (n=46) and Group 2: patients with no failure (n=122).Demographic characteristics, medical comorbidities, preoperative doppler ultrasound mapping results, laboratory parameters, postoperative follow-up details of these patients were collected. Primary patency of all patients, early failure rate, maturation failure rate, duration of CVC was calculated. Results: Female gender was found to be a significant risk factor in early failure of RCAVF (69.5% vs 36.1%; p=0.001). The number of patients whose diameter of cephalic vein< 2 mm were significantly higher in EF group (78.3% vs 22.1 ; p=0.028). The duration of CVC access of group 1 was significantly longer than group 2 (6.8 ± 3.6 months vs 2.3 ± 1.7 months, respectively; p<0.05). Overall maturation failure rate was 12.5% and primary patency at 1 year was 72.6%. Levels of C-Reactive protein (7.2 ± 9.6 vs 3.1 ± 3.3 mg/L, respectively; p=0.001) and neutrophil lymphocyte ratio (2.91± 0.30 vs 2.17 ± 0.22, respectively; p<0.05) was significantly lower at group 2 at one year. Conclusion:In patients whose VA for HD treatment was provided by CVC, small cephalic vein diameter, female gender and systemic inflammation may play a role in early failure of RCAVF.

Role of early postoperative ultrasonography in prediction of AV fistula failure in hemodialysis patients

BackgroundDoppler ultrasonography (US) is the main imaging modality of hemodialysis AV fistula as it is safe non-invasive accurate modality. This study is to measure the arteriovenous (AV) fistula blood flow during early postoperative period (7–14 days) and assess its predictive role in AV fistula failure in hemodialysis patients. Color Doppler ultrasonography (CDU) was used to estimate the blood flow in the AV fistula of 100 patients at (7–14 days) after the fistula creation. The performance of fistula blood flow during early postoperative periods for predicting fistula failure was evaluated, and optimal cutoff value was determined.ResultsDuring the follow-up period (6 months), we classified the fistulas as 82 mature, and 18 failed. The blood flow was considerably lower in the failure group than that in the mature group at the early postoperative period (P value = 0.001). The areas under the curves (AUC) were 0.952, and the cutoff value was 200.5 ml/min. The sensitivity of CDU in prediction of fistula failure is 99% with negative predictive value 94% and accuracy 97%, and with specificity 89% and positive predictive value 98%.ConclusionMeasuring blood flow of the AV fistula at the early postoperative period probably has a predictive role in the AV fistula failure. There is risk of failure if the blood flow less than 200 ml/min at (day 7–14)

Predicting arterio-venous fistula failure by urea-method derived access blood flow in chronic hemodialysis patients.

Dialysis access is an essential part of hemodialysis. Determining the access blood flow (Qa) can help predict arterio-venous fistula thrombosis. Qa determination by the urea method, which was previously described in the past is simple and is available in most of the dialysis units but was not be able to predict arterio-venous fistula thrombosis. To compare the efficacy of Qa determination by the urea method and by ultrasound dilution methods in predicting arterio-venous fistula failure. Qa was measured by urea method and by ultrasound dilution simultaneously, every 3 months for a period of 1 year, in stable chronic hemodialysis patients with arterio-venous fistula. Arterio-venous fistula failure determined by clinical parameters and confirmed by Doppler ultrasound before sending the patient for interventional angioplasty. This study enrolled a total of 16 patients, with 63% being male, 75% with lower-arm arterio-venous fistula and around 43% with previously done angioplasty. 59-Qa measurements were done, and 6 patients underwent angioplasty (one patient for severe upper limb edema, one for access thrombosis, and four for access dysfunction). Qa determination by the urea method had non-significantly lower Qa, (745 mL/min (interquartile range: 509-1143) and 779 mL/min (interquartile range: 530-1160), (p = 0.58)) and high correlation (r = 0.83, p < 0.001) to Qa by ultrasound dilution. The cut-off criteria with its sensitivity and specificity in predicting the access failure were 440 mL/min, 66.67%, and 96.15% for Qa determination by the urea and 400 mL/min, 66.67% and 90.38% for Qa by ultrasound dilution, respectively, with no difference in the area under the receiver operating characteristic curve. Measurement of Qa determination by the urea method is well correlated with Qa by ultrasound dilution and can be used to predict vascular access failure.

Abstract 460: Adventitial Delivery of Nanoparticle Hydrogel-calcitriol Attenuates Restenosis in a Murine Angioplasty Model

Background: Percutaneous transluminal angioplasty (PTA) is the first-line treatment for arteriovenous fistula (AVF) failure and immaturation. High rate of restenosis occurs post PTA procedure caused by venous neointimal hyperplasia (VNH), and decrease the durability of it. Failed AVF showed increased gene expression of Ier3. Poly lactic- co -glycolic acid nanoparticles (PLGA) loaded with 1,25-dihydroxyvitamin D 3 (1,25 NP) can inhibit Ier3 gene expression. Hypothesis: Adventitial delivery of 1,25 NP in hydrogel will reduce venous stenosis in a murine PTA model. Methods: Male C57BL/6J mice underwent partial nephrectomy at day -42 and arteriovenous fistula (AVF) creation at day -14. At day 0, mice were randomized to vehicle group (PTA + PLGA hydrogel) or treatment group (PTA + 1,25 NP hydrogel). Mice were euthanized at day 3 for gene expression analysis and at day 21 for histopathological analysis. Doppler ultrasound was performed weekly to evaluate AVF patency and function. Results: At day 3, PTA + 1,25 NP treated vessels had a significant decrease in the gene expression of Ier3 compared to controls. At day 21, 1,25 NP treated outflow veins had increased lumen vessel area, apoptosis, and higher peak systolic velocity, but decrease in neointimal area/media area ratio, fibroblasts, pro-inflammatory macrophages (M1), fibrosis (picrosirius red staining) and cellular proliferation. Conclusion: Adventitial delivery of 1,25 NP plus PTA has the ability to reduce restenosis and VNH formation. This protective effect is related to inhibition of Ier3 gene expression which modulates vascular inflammation and fibrosis post PTA.

A prospective cohort study of predictors of upper extremity arteriovenous fistula maturation.

A substantial proportion of arteriovenous fistulas fail to function adequately for hemodialysis. Existing studies on arteriovenous fistula failure prediction assess patency rather than the more clinically relevant outcome of arteriovenous fistula function. We hypothesized that preoperative demographic and ultrasound characteristics, and postoperative assessment by an experienced vascular access nurse would predict which arteriovenous fistulas will not function adequately for hemodialysis. Prospective cohort study of chronic kidney disease patients at a tertiary care center in Vancouver, Canada, with arteriovenous fistula creation between 2009 and 2013. Pre and postoperative clinical assessment and ultrasound blood vessel mapping were performed by an experienced vascular access nurse. The primary outcome was failure to achieve a fistula used successfully for hemodialysis (FUSH). Outcomes were assessed in 200 patients; 123 (61.5%) arteriovenous fistulas were radiocephalic. Overall, 26.5% of arteriovenous fistulas had FUSH failure (34.1% of lower arm vs 14.3% of upper arm, p = 0.002). Univariate predictors of FUSH failure included older age (p = 0.03), female sex (p = 0.05), smaller arterial diameter (p ⩽ 0.001), lower artery volume flow (p = 0.04), and smaller vein diameter (p = 0.01). In multivariable analysis, artery diameter (odds ratio: 0.44, 95% confidence interval: 0.28-0.68) most significantly predicted FUSH failure. Vascular access nurse assessment 6 weeks postoperatively correctly predicted outcome in 83.8% of FUSH and 65.0% of FUSH failure. Smaller artery diameter most strongly predicted FUSH failure. Early postoperative nursing assessment was more useful to predict FUSH than FUSH failure, and as such was insufficient in determining which arteriovenous fistulas should be abandoned as many predicted to fail could be salvaged with further intervention.

The efficacy of percutaneous transluminal angioplasty for the endovascular management of arteriovenous fistula dysfunction: a retrospective analysis in patients with end-stage renal disease.

To evaluate efficacy of percutaneous transluminal angioplasty (PTA) for the endovascular management of arteriovenous fistula (AVF) dysfunction in patients with end-stage renal disease (ESRD). A total of 135 consecutive patients with ESRD (mean±SD age: 58.8±9.4 years, 74.8% were males) who underwent endovascular treatment for a dysfunctional native AVF were included in this retrospective single-center study. Data on patient demographics, etiology of ESRD, characteristics of AVF, stenotic segments, PTA parameters and postoperative recurrence and patency rates within the 12 months were recorded. Technical and clinical success rates of PTA were 100.0% and 97.0%, respectively. Dysfunction recurrence rate was 30.4%. In patients with vs. without presence of recurrent AVF dysfunction, there was higher percentage of males (P=0.030), older age (P=0.018), diabetic or hypertensive rather than polycystic etiology (P<0.001), younger AVF (P<0.001), longer-segment stenosis (P=0.019) and lower median number (P=0.038) of stenotic segments. Presence of hypertension (OR 12.23, 95% CI: 4.29 to 34.85, P<0.001) and age of the AVF (OR 1.04, 95% CI: 1.00 to 1.08, P=0.029) were significant determinants of increased risk of recurrent AVF dysfunction. Our findings emphasize favorable safety and efficacy of PTA in the management of dysfunctional hemodialysis AVFs in terms of high technical and clinical success and low rates of residual stenosis, complications and post-PTA recurrence of AVF dysfunction. Male gender, older patient age, younger AVF and longer-segment stenosis were associated with higher likelihood of AVF failure, whereas hypertension and age of AVF were the two significant determinants of increased risk of post-PTA recurrence of AVF dysfunction.

Assessment of brachial artery mechanics using velocity vector imaging does not predict arteriovenous fistula failure; a feasibility study

Strain measurements by US have been suggested as a method of assessing arterial elasticity prior to arterio venous fistula creation. This pilot study sought to develop an imaging protocol to measure strain in the brachial artery via velocity vector imaging (VVI) and determine if differences in strain could be observed between a healthy group and a group with end-stage renal disease (ESRD), and if VVI measurements were associated with arterio-venous fistula malfunction. 40 healthy volunteers and 33 patients with ESRD were included in this study. All participants underwent US assessment of brachial artery strain via VVI. Peak velocity, strain, strain-rate and velocity were assessed. Patients with and without AVF failure at 3-months were assessed for differences in VVI measurement. Mean VVI measurements between the patient and volunteer groups were similar, and no significant differences were observed. Measurements were reproducible. No significant differences were observed in patients with or without AVF dysfunction. The results from this pilot study suggest VVI measurements of brachial artery mechanics are feasible and that VVI measurements may be used to assess age related changes of the brachial artery.

Computational Analysis of Turbulent Hemodynamics in Radiocephalic Arteriovenous Fistulas to Determine the Best Anastomotic Angles

Hemodynamics has been known to play a major role in the development of intimal hyperplasia leading to arteriovenous fistula failure. The goal of our study is to investigate the influence of different angles of side-to-end radiocephalic anastomosis on the hemodynamic parameters that promote intimal dysfunction and therefore intimal hyperplasia. Realistic three-dimensional meshes were reconstructed using ultrasound measurements from distal side-to-end radiocephalic fistulas. The velocity at the proximal and distal radial inflows and at specific locations along the anastomosis and cephalic vein was measured through duplex ultrasound performed by a single examiner. A computational parametric study, virtually changing the inner angle of anastomosis, was performed. For this purpose, we used advanced computational models that include suitable tools to capture the pulsatile and turbulent nature of the blood flow found in arteriovenous fistulas. The results were analyzed in terms of velocity fields, wall shear stress distribution, and oscillatory shear index. Results show that the regions with high oscillatory shear index, which are more prone to the development of hyperplasia, are greater and progressively shift toward the anastomosis area and the proximal vein segment with the decrease of the inner angle of anastomosis. These results are specific to distal radiocephalic fistulas because they are subject to proximal and distal radial inflow. The results of this study show that inner anastomosis angles approaching 60-70° seem to yield the best hemodynamic conditions for maturation and long-term patency of distal radiocephalic fistulas. Inner angles greater than 90°, representing the smooth loop technique, did not show a clear hemodynamic advantage.

Atorvastatin Reduces In Vivo Fibrin Deposition and Macrophage Accumulation, and Improves Primary Patency Duration and Maturation of Murine Arteriovenous Fistula.

Arteriovenous fistulas placed surgically for dialysis vascular access have a high primary failure rate resulting from excessive inward remodeling, medial fibrosis, and thrombosis. No clinically established pharmacologic or perisurgical therapies currently address this unmet need. Statins' induction of multiple anti-inflammatory and antithrombotic effects suggests that these drugs might reduce arteriovenous fistula failure. Yet, the in vivo physiologic and molecular effects of statins on fistula patency and maturation remain poorly understood. We randomized 108 C57Bl/6J mice to receive daily atorvastatin 1.14 mg/kg or PBS (control) starting 7 days before end-to-side carotid artery-jugular vein fistula creation and for up to 42 days after fistula creation. We then assessed longitudinally the effects of statin therapy on primary murine fistula patency and maturation. We concomitantly analyzed the in vivo arteriovenous fistula thrombogenic and inflammatory macrophage response to statin therapy, using the fibrin-targeted, near-infrared fluorescence molecular imaging agent FTP11-CyAm7 and dextranated, macrophage-avid nanoparticles CLIO-VT680. In vivo molecular-structural imaging demonstrated that atorvastatin significantly reduced fibrin deposition at day 7 and macrophage accumulation at days 7 and 14, findings supported by histopathologic and gene-expression analyses. Structurally, atorvastatin promoted favorable venous limb outward remodeling, preserved arteriovenous fistula blood flow, and prolonged primary arteriovenous fistula patency through day 42 (P<0.05 versus control for all measures). These findings provide new in vivo evidence that statins improve experimental arteriovenous fistula patency and maturation, indicating that additional clinical evaluation of statin therapy in patients on dialysis undergoing arteriovenous fistula placement is warranted.

A new approach to vein and arteriovenous fistula dilation

Dr Sanjai Desai, Dr Nicholas Inston, and Dr Alexandros Mallios provide an update on a new method to enhance vascular access outcomes for dialysis patients. While arteriovenous fistulas (AVFs) are the ‘gold standard’ for haemodialysis access, the path to a functional AVF is steep, and far too many fail before they can be used for dialysis. Fist Assist, a lightweight, wearable medical device, provides gentle, intermittent pneumatic compression that can safely and effectively help veins to enlarge before, and after, AVF surgery. This article covers the risks of AVF failure, early research with Fist Assist on dilation, a concise cost analysis, and the potential for such a device to improve outcomes for both percutaneous and standard AVFs. Fist Assist is expected to launch in Europe in March 2020.

Co-culture of human fibroblasts, smooth muscle and endothelial cells promotes osteopontin induction in hypoxia.

Arteriovenous fistulas (AVFs) are the preferred vascular access for haemodialysis of patients suffering from end‐stage renal disease, a worldwide public health problem. However, they are prone to a high rate of failure due to neointimal hyperplasia and stenosis. This study aimed to determine if osteopontin (OPN) was induced in hypoxia and if OPN could be responsible for driving AVF failure. Identification of new factors that participate in remodelling of AVFs is a challenge. Three cell lines representing the cells of the three layers of the walls of arteries and veins, fibroblasts, smooth muscle cells and endothelial cells, were tested in mono‐ and co‐culture in vitro for OPN expression and secretion in normoxia compared to hypoxia after silencing the hypoxia‐inducible factors (HIF‐1α, HIF‐2α and HIF‐1/2α) with siRNA or after treatment with an inhibitor of NF‐kB. None of the cells in mono‐culture showed OPN induction in hypoxia, whereas cells in co‐culture secreted OPN in hypoxia. The changes in oxygenation that occur during AVF maturation up‐regulate secretion of OPN through cell‐cell interactions between the different cell layers that form AVF, and in turn, these promote endothelial cell proliferation and could participate in neointimal hyperplasia.

Predictors of Arteriovenous Fistula Early Failure in End-Stage Renal Disease Patients: Real-World Data in Surabaya

Arteriovenous fistula (AVF) is the vascular access of choice in prevalent hemodialysis end-stage renal disease (ESRD) patients. However, there was a significant proportion of early AVF failure and its predictive factor was conflicting in several studies. We conducted a retrospective cohort study in 225 AVFs created in 159 patients. The purpose of this study was to identify the predictive factors of AVF early failure. The data variables included age at AVF creation, sex, history of diabetes, hypertension, cigarette smoking, AVF location and side, history of subclavian tunneled dialysis catheter and history of preoperative ultrasound mapping. This information was collected by interviewing the patient and by AVF scar inspection. AVF that was never coming into use was classified as an early failure. AVF creation in the wrist was significantly associated with a higher early failure rate (29.9%) compared with AVF creation at the elbow (4.4%) (p < 0.001). There was no significant association in terms of AVF early failure in terms of the other variables. We concluded that wrist AVF is significantly associated with early failure. However, this finding should not preclude the National Kidney Foundation’s recommendation of using wrist AVF for the first choice of vascular access to conserve more proximal access sites for future use.

Primary Failure of Autogenous Arteriovenous Fistula: Critical Analysis.

Introduction:Permanent vascular access is an essential intervention in patients with advanced chronic kidney disease (CKD) and its success depends on various non-modifiable and modifiable factors. Considering the element of unpredictability and failure, we attempted to analyze various factors responsible for primary arteriovenous fistula (AVF) failure in presumed high-risk groups.Materials and Methods:We conducted an observational study of newly created AVFs at a tertiary referral government hospital in Eastern India between January 2014 and June 2015. All adult CKD patients undergoing AVF creation were included. Primary AVF failure was assessed at 12 weeks and total follow-up was 24 weeks in presumed high-risk groups of females, patients aged ≥65 years and those with diabetes mellitus.Results:Female gender was at a higher risk of primary AVF failure if aged ≥65 years (P = 0.0026), second AVF creation (P = 0.03), loupe magnification not used (P = 0.03), arterial plaque (P = 0.028), absent immediate thrill, and with radiocephalic AVF (P = 0.02). Absent immediate thrill (<0.0001) and AVF size ≤5 mm (P = 0.002) were important independent risk factors for primary failure. Diabetes or elderly age did not have additional risk, except with uncontrolled hypertension and female gender.Conclusion:Female gender was at a higher risk of poor unassisted AVF patency if their age was ≥65 years, had second AVF creation, loupe magnification not used or if arterial plaque was present. An absence of thrill immediately or at 24 hours or an AVF diameter ≤5 mm were independent intraoperative factors for poor outcome. On the contrary, diabetics, elderly males and intimal thickness were essentially noncontributors for AVF failure, except in few subsets.

A mouse model of stenosis distal to an arteriovenous fistula recapitulates human central venous stenosis

ObjectiveCentral venous stenosis (CVS) is a major cause of arteriovenous fistula (AVF) failure. However, central veins are relatively inaccessible to study with conventional Doppler ultrasound methods. To understand mechanisms underlying AVF failure owing to CVS, an animal model was established that creates a stenosis distal to an AVF. We hypothesized that this mouse model will show comparable morphology and physiology to human CVS. MethodsAn aortocaval fistula was created between the distal aorta and inferior vena cava (IVC); a stenosis was then created distal to the fistula by partial IVC ligation. Sham-operated animals, AVF without venous stenosis, and venous stenosis without AVF were used as controls. Physiologic properties of the IVC, both upstream and downstream of the stenosis, or the corresponding sites in models without stenosis, were assessed with ultrasound examination on days 0 to 21. The spectral broadening index was measured to assess the degree of disturbed shear stress. The IVC was harvested at day 21 and specimens were analyzed with immunofluorescence. ResultsThe IVC diameter of mice with an AVF and stenosis showed increased upstream (P = .013), but decreased downstream diameter (P = .001) compared with mice with an AVF but without a stenosis, at all postoperative times (days 3-21). IVC wall thickness increased in mice with an AVF, compared with IVC without an AVF (upstream of stenosis: 13.9 μm vs 11.0 μm vs 4.5 μm vs 3.9 μm; P = .020; downstream of stenosis: 6.0 μm vs 6.6 μm vs μm 4.5 μm vs 3.8 μm; P = .002; AVF with stenosis, AVF, stenosis, sham, respectively). AVF patency significantly decreased in mice with an AVF and stenosis by day 21 (50% vs 90%; P = .048). The IVC of mice with AVF and stenosis showed a venous waveform with pulsatility as well as enhanced velocity at and downstream of the stenosis; similar waveforms were observed in a human case of CVS. Downstream to the stenosis, the spectral broadening index was significantly higher compared with mice with AVF alone (1.06 vs 0.78; P = .011; day 21), and there was a trend towards less immunoreactivity of both Krüppel-like factor 2 and phosphorylated-endothelial nitric oxide synthase compared with mice with an AVF alone. ConclusionsPartial IVC ligation distal to a mouse aortocaval fistula alters the fistula diameter and wall thickness, decreases patency, and increases distal disturbed flow compared with fistulae without a distal stenosis. Our mouse model of stenosis distal to an AVF may be a faithful representation of human CVS that shows similar morphology and physiology, including disturbed shear stress.

The Role of Far Infrared Therapy in the Unassisted Maturation of Arterio-venous Fistula in Patients with Chronic Kidney Disease.

Introduction:The goal of arterio-venous fistula (AVF) creation is to achieve a well-functioning access that can be cannulated repetitively and can provide adequate flow for the dialysis. The objective of this study was to assess the role of far infrared (FIR) therapy in the unassisted maturation of newly created AVF in patients with chronic kidney disease (CKD).Materials and Methods:In this prospective open labeled randomised control trial, 107 patients were randomized. Participants in the control arm received oral clopidogrel 75 mg once daily for 30 days along with isometric hand exercise, whereas those in the test arm received FIR therapy twice weekly, 40 min session each, for 4 weeks. A biopsy from venous end was taken during fistula surgery. Doppler study of AVF was done at the end of the 4th and 12th week to assess AVF. Vascular access guidelines proposed by National Kidney Foundation –Kidney Disease Outcomes Quality Initiative (NKF- KDOQI) in 2006 were adapted to define the maturation of AVF.Results:Out of 107 patients, 51 were randomized to the test arm and 56 to the control arm. During follow-up, the blood flow rate through AVF (Qa) and the diameter of the cephalic vein draining (CVd) the AVF were measured. At the end of 3 months, Qa in Radio-Cephalic Fistula (RCF) was high in the test arm (p–0.003). The AVF failures were 5 (10.2%) and 14 (28%) in the test and control arms, respectively (p: 0.025). However, when adjusted for AVF failure within 6 h of surgery (may be related to surgical technique) this difference in AVF patency was statistically insignificant (p: 0.121). The mean Qa was high in patients with an arterial intimal medial thickness (AIMT) <0.5 mm. The IMT of the anastomosed artery had statistically significant correlation with the primary failure rate of AVF (P < 0.001).Conclusion:In patients with CKD, FIR therapy was effective in increasing the AVF blood flow rate at the end of 3 months, though the difference in primary failure rate was statistically insignificant.

The influence of a doppler ultrasound in arteriovenous fistula for dialysis failure related to some risk factors.

ABSTRACTIntroduction:The increasing prevalence of chronic kidney disease has increased the demand for arteriovenous fistula (AVF) care. The objective of this study was to assess the relationship between some risk factors for AVF failure (advanced age, female sex, diabetes, obesity, central venous catheter, previous fistula, and hospitalization) and having a Doppler ultrasound performed preoperatively.Methods:A prospective study was performed with 228 dialysis patients from Imperatriz, Maranhão. Half of the sample was randomly selected to receive preoperative Doppler ultrasound and the other half did not, from the period of October 2016 to September 2018.Results:There were 53 total failures corresponding to 23.2% of our sample, which is almost double that of the patients in the clinical group. Considering the failures and risk factors associated with the overall sample, there was a statistically significant association between a central venous catheter on the same side of the AVF with P = 0.04 (Odds Ratio 1.24) and obesity with P = 0.05 (Odds Ratio 1.36), which was not repeated in the Doppler ultrasound group individually. There was no statistically significant difference between the Doppler group and clinical group with respect to the amount of days of previous AVF hospitalization and failure.Conclusions:We concluded that the reduction of failures with an introduction of the Doppler was statistically significant in the overall sample, but establishing a relationship between specific risk factors and failure was only possible with two of the risk factors in the study - obesity and central venous catheter on the same side of the AVF.

Outcomes of endovascular procedures in salvage of arteriovenous fistulas via the transradial route: A prospective study

Aim: To evaluate the primary patency and predictors of technical failure of arteriovenous fistulae (AVF) following transradial percutaneous transluminal angioplasty (PTA). Materials and Methods: This was a prospective study being conducted to evaluate the primary patency and predictors of technical failure of AVF following transradial PTA. This will help us identify high-risk patients and plan interventions in them at an earlier time to avoid access loss. The time period of the study was from October 2016 to October 2018 in the Department of Vascular and Endovascular Surgery at Sri Ramachandra Medical College, Chennai, Tamil Nadu. A total of 44 patients were included in this cohort and they were all followed up in the outpatient department and via telephonic contact for a period of 1 year. All the patients who underwent endovascular AVF salvage fitting the inclusion criteria were included in the study. The demographics of the patients were recorded at admission and patients were investigated for the cause of fistula dysfunction at the treating physicians discretion and an ultrasound Doppler was ordered for all patients to ascertain the cause of the stenosis. The statistical analysis was done by the ANOVA and t-test. Results: A total of 44 patients were included in this cohort and they were all followed up for a period of 1 year. The 30-day, 90-day, 6-month, and 12-month primary patencies were 84.1%, 81.8%, 63.63%, and 43.18%, respectively. Our technical success was 88.6%. In our study, we found that longer lesion lengths (>4 cm) were prone to early loss of primary patency and this was statistically significant. We found that patients above 60 years of age had lower primary patencies and the presence of diabetes mellitus also lowered the primary patency. Fistula maturation age did not show a correlation with patency in our cohort. Male patients had a higher patency rate and juxta-anastomotic stenoses postangioplasty had a higher primary patency due to the shorter lengths. Radiocephalic fistula angioplasties had a higher patency as compared to brachiocephalic angioplasty. Conclusion: Ours is the first study in India to proactively and preferably use the transradial approach over the transvenous approach, as it confers many benefits. The challenges of the transradial route are the smaller size of the radial artery in the Indian population as compared to the western population.

Complications of permanent vascular access in hemodialysis patients

Background Vascular access (VA) complications are still considered a significant cause of morbidity and mortality in hemodialysis (HD) patients. The research aimed to study the complications of permanent VA in HD patients: single-center experience. Patients and methods This was a 1-year prospective, observational study conducted in a HD Unit, Department of Nephrology in 2018. 230 HD patients were recruited for the study, and they were subjected to clinical examination in each HD session. Culture and sensitivity of a swab sample of the VA was performed to confirm the diagnosis of infection. Also, Doppler ultrasound was used to evaluate the VA when there had been a suspicion of complications. Data were analyzed using the software Statistical Package for The Social Sciences. Results Arteriovenous fistula (AVF) was the predominant VA, and radiocephalic AVF was the most common type, followed by the brachiocephalic type. The most frequent complication was aneurysm (39.6%), followed by thrombosis (7%), stenosis (5.2%), infection (4.3%), and arterial steal syndrome (2.2%). Thrombosis was the leading cause of AVF failure, and antiplatelet therapy was a protective factor from thrombosis. Infection was the second cause of VA failure and Staphylococcus aureus infection was the most common type. Elbow AVF was considered as a predisposing risk factor of arterial steal syndrome. Conclusion VA complications are not rare, and they could cause VA failure. So, it is necessary to make more efforts and work as a multidisciplinary team.

Survival and Prognostic Predictors of Primary Arteriovenous Fistula for Hemodialysis.

Objectives: This study aims to evaluate the survival and prognostic predictors of arteriovenous fistulas (AVFs) among patients undergoing AVF creation. The significant predictors were incorporated into a prognostic model to determine its prognostic performance for five-year AVF survival.Materials and Methods: Data on 290 patients who underwent first-time AVF creation and who had been followed up for at least 5 years or until AVF failure were reviewed. The Kaplan–Meier survival curves and Cox proportional hazards model were generated to determine the AVF survival and associated prognostic predictors. Significant predictors were used to derive a prognostic model.Results: The mean age of the patients was 59.7±14.6 years, and the 5-year AVF survival rate was 34.5%. Three features were found to be independent prognostic factors for the five-year AVF survival: old age, diabetes mellitus, and prior central venous catheter placement. These three significant factors were integrated into a prognostic scoring model that ranged from zero to five points. According to this model, the patients whose scores were 0, 1, 2, 3 and 4 or more had five-year AVF survival rates of 60.0%, 45.3%, 36.6%, 15.0%, and 2.9%, respectively.Conclusion: The five-year survival rate of AVFs was modest, and a prognostic model could excellently estimate the five-year AVF survival.

Diagnostic validity of CAVeA2T2 score in predicting failure of radiocephalic arteriovenal fistula in terminal stage renal failure patients at Sanglah Hospital, Bali, Indonesia

Introduction: Chronic kidney disease (CKD) is a global public health problem with increasing prevalence and incidence and poor prognosis. As a result, more patients will be in terminal stage kidney failure and require placement of vascular access for hemodialysis. Mature and functional arteriovenous fistula (AVF) is considered the best modality for access to hemodialysis. This study aims to examine the CAVeA2T2 scores in predicting failure of arteriovenous fistula radiocephalic, significant factors related to failure of arteriovenous fistula so that it can be used to predict failure using a scoring system to predict primary failure and secondary failure fistula.Methods: A cross-sectional study was carried out at Sanglah Hospital, Bali, Indonesia, during the study period. This study using diagnostic test evaluation method using ROC curve analysis on months 1 and 3, a total of 50 populations obtained using Purposive sampling quota period April 2018 - December 2018 and failure of Hemodialysis as gold standard. Data were analyzed using Stata version 12 for Windows.Results: Results of the CAVeA2T2 score where the maximum score of 7 was analyzed using the ROC curve, the cutoff point was obtained at month 1 ≥5 with AUC 0.8987 and at 3 months ≥ 4 with AUC 0.3966 sensitivity and specificity CAVeA2T2 score of 91.3% and 75% in month 1, in the 3rd month 85.7% and 87.5% were obtained.Conclusion: Sensitivity and specificity values that provide a good value so that the CAVeA2T2 score can be used to predict failure of arteriovenous radiocephalic fistulas.