Access Patency Research Articles

Preoperative Vein Mapping is Not Associated With Arteriovenous Access Type Created But is Associated With Improved Patency

Autogenous arteriovenous (AV) fistulas are preferred for hemodialysis access, with AV grafts (AVGs) reserved for when a suitable vein is unavailable. Preoperative vein mapping can be used to identify usable veins for autogenous access. We evaluated whether vein mapping is associated with access type and outcomes. We queried the Vascular Quality Initiative database for patients who had undergone initial AV access creation from 2011 to 2019. We evaluated the associations of preoperative vein ultrasound/venogram mapping with patient characteristics, access type, and 30-day and 1-year patency. Of 20,461 patients receiving an initial AV access, 92% had undergone preoperative vein mapping. The patients who had undergone vein mapping were more likely to be women (43.1% vs 39.8%; P = .01), outpatients (84.1% vs 81.2%; P = .002), obese (43.3% vs 39.2%; P = .002), and diabetic (62.6% vs 59.8%; P = .03). They were also more likely to have concomitant coronary artery disease (21.8% vs 18.9%; P = .008), congestive heart failure (31.3% vs 25.9%; P < .001), and concurrent tunneled dialysis catheters (43.7% vs 35%; P < .001) and to already require dialysis (55.8% vs 52%; P = .004). We found no significant difference in AVG creation between the patients who had and had not undergone vein mapping (14.2% vs 13.6%; P = .5). Furthermore, no significant correlation was found between the proportions of preoperative vein mapping and AVG creation at the center and regional levels (P = .14 and P = .1; and P = .4 and P = .11, respectively). Preoperative vein mapping was associated with higher 30-day patency (94.7% vs 90%; P = .001) and 1-year patency (90% vs 82%; P < .001) for autogenous access. On multivariable analysis, concurrent tunneled dialysis catheter use, congestive heart failure, coronary artery disease, obesity, female sex, and outpatient status were independently associated with increased preoperative vein mapping use (P < .05 for all). Preoperative vein mapping was not independently associated with AVG creation likelihood (odds ratio, 0.98; 95% confidence interval [CI], 0.81-1.17; P = .8) but was independently associated with increased 30-day patency (odds ratio, 2.23; 95% CI, 1.44-3.45; P < .001) and 1-year patency (hazard ratio, 1.56; 95% CI, 1.19-2.04; P = .001). Preoperative vein mapping was more likely to be performed in patients presenting with cardiovascular comorbidities and potential technical concerns. Vein mapping did not appear to minimize AVG creation; however, it was associated with improved autogenous access patency. Although most patients received preoperative vein mapping, increasing its use might further improve access outcomes.

Single Arterial Retrograde Access for Arteriovenous Access Declot in the Office-Based Laboratory

We have described a time- and cost-efficient method for urgent percutaneous arteriovenous (AV) access declotting in the office-based laboratory (OBL). The need for declotting is an urgent case that disrupts the patient's dialysis and the surgeon's schedule and is traditionally treated by a single surgeon using bidirectional AV access. This technique is challenging, inefficient, and increases the risk of sterility breach. We evaluated a single arterial retrograde access (SARA) approach to declotting. The declot procedures were performed in the OBL for patients with thrombosed AV access referred by the dialysis center. Ultrasound-guided SARA of the brachial or radial artery was performed using a micropuncture needle. Fistulogram was performed through the transitional dilator to confirm the presence of thrombosis. Via a 5F × 4-cm sheath, the fistula was cannulated using an angled 0.035-in. glidewire. Next, a 0.035-in. Amplatz wire was placed, and 4 mg of tissue plasminogen activator was instilled using a Touhy Bourse via an angled support catheter. Blind percutaneous venous outflow angioplasty was performed with a 7-mm × 60-mm percutaneous transluminal angioplasty balloon. Proximal inflow thrombectomy was performed using a 5-mm × 40-mm percutaneous transluminal angioplasty balloon. Next, thrombus maceration and outflow thrombectomy were performed using both the 5-mm and 7-mm balloons until a thrill was palpated. Completion angiogram confirmed AV access patency and ruled out extravasation and distal arterial emboli. The OBL staff maintained manual pressure for 30 minutes. Nine patients had undergone 11 procedures with 100% technical success. One patient had required repeat thrombectomy within 30 days. No complications, including bleeding or ischemic events, occurred. All patients were able to return to dialysis successfully within 24 hours. At the last follow-up, all nine fistulas were patent and functional. In our OBL, the average cost for bidirectional AV access thrombectomy was $1170 and the average cost for the SARA procedure was $843.67. The physician time was 39.5 minutes for SARA and 47.4 minutes for bidirectional access. No treatment failures occurred in our series. The results from the present series have demonstrated that SARA is a safe, time-efficient, and cost-effective method to address clotted access in the OBL. This technique leverages fixed OBL costs, and allows the surgeon to help treat other patients.

Use of the helical SUPERA™ stent and Passeo-18 Lux™ drug-coated balloon to treat recurrent cephalic arch stenosis for dysfunctional brachiocephalic fistulas: 1 year results of the Arch V SUPERA-LUX study.

Aim of Arch V SUPERA-LUX was to evaluate the safety and efficacy of the combination therapy of SUPERA™ (Abbott Vascular, Santa Clara, CA, USA) helical stent implantation and Passeo-18 Lux™ (Biotronik Asia Pacific Pte Ltd, Singapore) drug coated balloon (DCB) elution to treat recurrent cephalic arch stenosis (CAS) in the setting of AV access dysfunction. Investigator-initiated, single-center, single-arm prospective pilot study of 20 end-stage renal failure Asian patients with a dysfunctional brachiocephalic fistula. All had symptomatic recurrent CAS within 6 months of prior intervention. The lesion was pre-dilated with a standard high-pressure balloon (Biotronik Passeo-35 HP balloon). The DCB (Passeo-18 Lux™) is subsequently inflated and the SUPERA™ stent deployed to sit 2 mm distal to the cephalic arch and covering the CAS but within the DCB zone. All patients were prescribed dual antiplatelet therapy for 3 months and followed up with Duplex ultrasound at 6- and 12-months. There were 9 (45%) males and mean age was 67 ± 11.0 years. Mean time from prior procedure was 113 ± 68 days and main indication for reintervention was high venous pressure (9/20, 45%). Technical success was 100% and there were no peri-procedural complications related to either stent or DCB deployment. Target lesion primary patency at 6- and 12-months was 10/18 (55%) and 5/16 (31%), respectively. Mean time to target lesion re-intervention was 170 ± 82 days. Circuit access patency was 8/18 (44%) and 2/16 (13%) at 6- and 12-months respectively and mortality was 3/20 (15%) attributed to the patients' underlying co-morbidities. Dual prong strategy of using SUPERA™ stenting and Passeo-18 Lux™ drug elution for recurrent CAS, although safe, was no more efficacious than conventional balloon angioplasty or stenting alone. Development of an intense inflammatory reaction within the stent led to reinterventions of a number of cases with suboptimal results.

Balloon-assisted Maturation With Larger Diameter Balloons Should Be First-line Intervention for Nonmaturing Autologous Hemodialysis Access

Serial balloon-assisted maturation (BAM) is a well-established method to develop functional arteriovenous fistulas (AVFs) but often require multiple reinterventions. We hypothesized that initial BAM with a larger diameter balloon will lead to earlier maturation of AVF and lower rates of reintervention. A retrospective review of 173 consecutive patients who underwent BAM between 2018 and 2020 by a single vascular surgeon at a hospital setting was performed. The cohort was divided into Group I: patients that underwent initial BAM with an 8-mm balloon (n = 121), and Group II: patients that had initial BAM with <8-mm balloon (n = 52). An 8-mm balloon was not used if contrast extravasation was observed after angioplasty with a smaller balloon. Only procedures performed to achieve initial AVF maturation were included, and procedures performed to maintain access patency were excluded. AVF was considered matured if successfully used for dialysis on 3 consecutive sessions. Demographic data, procedural details, and outcomes were compared between the two groups. A total of 222 BAMs were performed: 152 in Group I and 70 in Group II. The overall maturation rate was 99% (172/173). All demographics were similar, with the exception of more women in group II (61.5% vs 35.8%; P = .003). Based on preprocedure duplex, there was no difference in the vein size (4.4 ± 1.2 vs 3.9 ± 1.4 mm; P = .122) and volume flow (723 ± 450 vs 492 ± 370 mL/min; P = .079) between groups. However, higher rate of AVF stenosis was noted in Group II (39.5%) as compared with Group I (17.9%; P = .007). Seventy-nine percent (n = 94) of the AVFs in Group I achieved maturation after the initial BAM as compared with 54.9% (n = 28) in Group II (P = .001). Forty-four percent (n = 23) of patients in Group II required additional procedures to achieve maturation vs 22.3% (n = 27) patients in Group I (P = .001). There was a similar incidence of intraprocedural contrast extravasation and post-procedural hematoma in both groups (10.7% vs 17.3%; P = .23). None of the complications required intervention nor did it impact AVF patency. We demonstrated that utilizing large angioplasty balloons during initial BAM is safe and allows to achieve AVF maturation with fewer number of procedures.

Angioplasty Induced Changes in Dialysis Vascular Access Compliance.

Dialysis vascular access remains vitally important to maintain life and functional capacity with end stage renal disease. Angioplasty is an integral part of maintaining dialysis access function and patency. To understand the effect of angioplasty balloon dilation on vascular wall mechanics, we conducted a clinical study to evaluate the elastic modulus of the anastomosis in five subjects with anastomosis stenoses, before and after six angioplasty procedures, using B-mode ultrasound DICOM data. A novel and open source vascular ultrasound high-resolution speckle tracking software tool was used. The median lumen diameter increased from 3.4 to 5.5 mm after angioplasty. Meanwhile, the median elastic modulus of the 18 measurements at the anastomosis increased by 52.2%, from 2.24×103 to 3.41×103mmHg. The results support our hypothesis that the structural changes induced in the vessel wall by balloon dilation lead to reduced vascular compliance and a higher elastic modulus of the vessel wall.

Factors Affecting the Long Term Patency of Arteriovenous Access for Hemodialysis

Objective: The objective of the study was to analyze and evaluate the possible factors in the long-term patency of arteriovenous (AV) access for hemodialysis (HD). Materials and Methods: This was a cross-sectional study recruiting patients from January 2019 to December 2019. All patients who have a working HD vascular access, either AV fistula (AVF) or AV graft which has been working for at least 2 years were included and collected demographic data along with other parameters such as timing of creation, interventions, dialysis sessions, and antiplatelet therapy among others. Results: We included 81 patients with AV access patent more than 2 years; 22.5% were aged &gt;65 years, 39.6% were diabetic, 68.5% were hypertensive, and 26.1% had vascular disease. Analysis revealed that the patient factors such as current tobacco usage and side of creation and technical factors such as maturation time, number of dialysis sessions, and single-center dialysis have a significant effect on the patency of the AV access, while the factors such as past tobacco usage, diabetes, hypertension, use of jugular catheter before access creation, and cannulation technique could not establish any statistical effect on the patency of AV access. Conclusion: There is a complex interaction of factors that may affect the patency of an individual AV access. These need to be carefully considered when selecting surgical site or technique, adjuvant treatments, and follow-up protocols for AVFs.

Comparison of Brachiobasilic Transposition Arteriovenous Fistula Outcomes among Diabetic and Non-diabetic Patients: A Case Controlled Study.

Diabetes is considered a risk factor for arteriovenous fistula failure and increased perioperative complications; but this view is not proven for patients undergoing brachiobasilic transposition arteriovenous fistula (BBT-AVF). Fifty-one (68.9%) diabetic and 23 (31.08%) non-diabetic patients undergoing single-stage BBT-AVF were compared in terms of perioperative complications, access maturation and patency rates at The Aga Khan University Hospital from between January 2016 to December 2017. Diabetics were elder and more obese. The perioperative complications 19 (37.2%) vs. 8 (34.7%), and access maturation rates were compared (93.2% vs. 95.5%) between the two groups. At 6 months, access patency in diabetics was lower compared to non-diabetics (64.7% vs. 87.0%). Similar trend was noted at 12 and 24 months in both groups. This study showed that the diabetic and non-diabetic were comparable in terms of perioperative complications and maturation rate. However, short term patency rate was lower in diabetics compared to non-diabetics. Key Words: Brachiobasilic AVF, Complications, Diabetes mellitus, Patency.

Is fetuin-A a biomarker of dialysis access dysfunction?

The arteriovenous (AV) access function of hemodialysis (HD) patients can be impaired by afferent artery stiffness due to preexisting microcalcification and by venous stenosis secondary to neointimal hyperplasia in whose development participates an upregulated local inflammatory process. Fetuin-A is a circulating potent inhibitor of vascular calcification and plays an important anti-inflammatory role. The aims of this prospective study were to investigate the relationship between baseline serum fetuin-A levels and: blood flow (QA) values at baseline, AV access failure (thrombosis or intervention for stenosis) during follow-up and primary unassisted AV access patency. We measured baseline serum fetuin-A levels and QA values of the AV access in 64 HD patients under routine QA surveillance for stenosis. Patients were classified into tertiles according to their baseline fetuin-A levels (g/L): <0.5 (tertile-1), 0.5-1.20 (tertile-2), and >1.20 (tertile-3). Fetuin-A was positively correlated with QA (Spearman coefficient = 0.311, p = 0.012). Fourteen patients (21.9%) underwent AV access failure and they had lower fetuin-A (0.59 ± 0.32 g/L) and lower QA (739.4 ± 438.8 mL/min) values at baseline compared with the remaining patients (1.05 ± 0.65 g/L and 1273.0 ± 596.3 mL/min, respectively) (p = 0.027 and p < 0.001, respectively). The AV access failure rate was highest (34.8%) in tertile-1 (lowest fetuin-A level). Unadjusted Cox regression analysis showed a decrease in the risk of AV access patency loss by increasing fetuin-A concentration (hazard ratio 0.395 (95% confidence interval: 1.42-1.69), p = 0.044) but it was not confirmed in the adjusted model, although the hazard ratio was low (0.523). Kaplan-Meier analysis showed that patients in tertile-3 (highest fetuin-A concentration) had the highest primary unassisted AV access patency (λ2 = 4.68, p = 0.030, log-rank test). If our results are confirmed in further studies, fetuin-A could be used as a circulating biomarker to identify HD patients at greater risk for AV access dysfunction, who would benefit from much closer dialysis access surveillance.

The role of Doppler ultrasonography in vascular access surveillance-controversies continue.

Chronic hemodialysis therapy required regular entry into the patient’s blood stream with adequate flow. The use of arteriovenous fistulas and grafts is linked with lower morbidity and mortality than the use of catheters. However, these types of accesses are frequently affected by stenoses, which decrease the flow and lead to both inadequate dialysis and access thrombosis. The idea of duplex Doppler ultrasound surveillance is based on the presumption that in-time diagnosis of an asymptomatic significant stenosis and its treatment prolongs access patency. Details of performed trials are conflicting, and current guidelines do not support ultrasound surveillance. This review article summarizes the trials performed and focuses on the reasons of conflicting results. We stress the need of precise standardized criteria of significant access stenosis and the weakness of the metaanalyses performed.

Computational modeling of the cephalic arch predicts hemodynamic profiles in patients with brachiocephalic fistula access receiving hemodialysis

The most common configuration for arteriovenous fistula is brachiocephalic which often develop cephalic arch stenosis leading to the need for numerous procedures to maintain access patency. The hemodynamics that contributes to the development of cephalic arch stenosis is incompletely understood given the inability to accurately determine shear stress in the cephalic arch. In the current investigation our aim was to determine pressure, velocity and wall shear stress profiles in the cephalic arch in 3D using computational modeling as tools to understand stenosis. Five subjects with brachiocephalic fistula access had protocol labs, Doppler, venogram and intravascular ultrasound imaging performed at 3 and 12 months. 3D reconstructions of the cephalic arch were generated by combining intravascular ultrasounds and venograms. Standard finite element analysis software was used to simulate time dependent blood flow in the cephalic arch with velocity, pressure and wall shear stress profiles generated. Our models generated from imaging and flow measurements at 3 and 12 months offer snapshots of the patient's cephalic arch at a precise time point, although the remodeling of the vessel downstream of an arteriovenous fistula in patients undergoing regular dialysis is a dynamic process that persists over long periods of time (~ 5 years). The velocity and pressure increase at the cephalic bend cause abnormal hemodynamics most prominent along the inner wall of the terminal cephalic arch. The topology of the cephalic arch is highly variable between subjects and predictive of pathologic stenosis at later time points. Low flow velocity and wall pressure along the inner wall of the bend may provide possible nidus of endothelial activation that leads to stenosis and thrombosis. In addition, 3D modelling of the arch can indicate areas of stenosis that may be missed by venograms alone. Computational modeling reconstructed from 3D radiologic imaging and Doppler flow provides important insights into the hemodynamics of blood flow in arteriovenous fistula. This technique could be used in future studies to determine optimal flow to prevent endothelial damage for patients with arteriovenous fistula access.

Intervention with selution SLR™ Agent Balloon for Endovascular Latent Limus therapy for failing AV Fistulas (ISABELLA) Trial: Protocol for a pilot clinical study and pre-clinical results.

The aim of this pilot clinical study is to evaluate the safety and efficacy of the Selution Sustained Limus Release (SLR)™ sirolimus-coated balloon (M.A. MedAlliance SA, Nyon, Switzerland) for improving the patency of failing arterio-venous fistulas (AVF) in hemodialysis patients. We also present herein a pre-clinical pharmacokinetic and safety evaluation of Selution™ to justify its first use in hemodialysis patients for endovascular access salvage. This is an investigator-initiated prospective single-center, non-blinded single-arm trial. Forty patients with clinically significant de novo or recurrent stenoses in a mature AVF circuit will be recruited. All stenotic lesions will be prepared with high pressure non-compliant conventional balloon angioplasty (CBA) prior to deployment of the Sustained-Release Selution™ sirolimus drug-eluting balloon. The primary efficacy endpoint is 6-month target lesion primary patency and the primary safety endpoint is freedom from localized or systemic serious adverse events through 30 days. Secondary endpoints of interest include technical and clinical success rates and circuit access patency at 3 and 6 months. Follow-up will occur for 2 years for those patients whose AVFs remain patent. Pharmacokinetic and histological animal safety studies performed with the Selution™ coating formulation showed prolonged arterial tissue retention of sirolimus with therapeutic levels up to 60 days and non-toxic and rapidly declining blood levels. Histological results in animal models demonstrated safety, freedom from intraluminal thrombus, reduction in restenosis by sirolimus elution compared to CBA, and no evidence of embolic phenomena indicative of adverse particulate effects. Long release sirolimus coated balloons may serve as a promising novel alternative therapy to paclitaxel-based technology for treating conduit stenosis secondary to neointimal hyperplasia. Pre-clinical pharmacokinetic and histological animal data are encouraging and provide suggestion of safety and efficacy in this setting. This single-center trial will provide a first step toward demonstration of efficacy and safety of this device for treatment of stenotic fistulas.

Heparin Infusion for Central Line Patency and Corrected Gestational Age May Affect Coagulation Studies in the Neonatal Intensive Care Unit

Introduction: Addition of heparin (i.e., 0.5-1 U/mL) to maintenance intravenous (IV) fluids in the neonatal intensive care unit (NICU) is frequently done to reduce the risk of thrombus-related catheter dysfunction. Since heparin could affect coagulation testing, we sought to determine whether coagulation study results are significantly affected by the presence of heparin in IV fluids.Methods: Chart review was performed on all patients in the NICU that had either prothrombin time (PT) or partial thromboplastin time (aPTT) drawn during their NICU course. Only the first instance of coagulation studies drawn on each patient was considered. Patients were excluded if they had a medical condition (e.g., sepsis) which could potentially affect coagulation studies or if they received blood products. Coagulation study results and whether or not the patient was receiving heparin in IV fluids for vascular access patency were extracted in addition to other demographic information, including corrected gestational age (CGA). In our institution, all NICU patients with a central line where the flow rate in any lumen is less than 5 mL/hr receive heparin. Comparative analyses between the group receiving heparin in IV fluids and the group not receiving heparin were performed. Wilcoxon rank sum test was used to detect differences in distribution between groups and adjustment was performed by fitting one multiple linear regression model to medians and a separate multiple linear regression model to standard deviations; Z-scores were calculated based off these two models.Results: One hundred and forty four patients (mean age 17.9 days, 50% male) were included in the analysis. Initial unadjusted analysis revealed that patients who received heparin in IV fluids for vascular access patency (n=77, 53.5%) had prolongation of PT and aPTT compared to patients who did not receive heparin (n=67, 46.5%) in IV fluids for vascular access patency (means 16.2 seconds vs. 13.5 seconds [p=8 x 10-7] and 62.9 vs. 43.9 seconds [p=9 x 10-8], for PT and aPTT, respectively). No significant sex-based difference was noted.In 132 patients with accurate CGA data available, mean CGA was lower in the heparin group (n=75) at 36.5 weeks compared to the no heparin group (n=57) at 41.6 weeks (p<0.0001). When results were adjusted for CGA, the difference remained significant but much less so (z-score mean difference 0.52 [p=0.01] and 0.48 [p=0.003], for PT and aPTT, respectively).Conclusion: Coagulation study parameters appear to be prolonged in patients receiving heparin for vascular access patency compared to those who are not; however, much of this difference is accounted for by corrected gestational age. Proper specimen collection (i.e., sufficient draw-back prior to collecting the sample) for accurate interpretation of results in these patients is recommended. In addition, laboratories should consider taking corrected gestational age and continuous low-dose heparin infusion into account when establishing reference ranges for coagulation studies. DisclosuresNo relevant conflicts of interest to declare.

MO775CONTROL OF BONE DISEASE ASSOCIATED WITH CHRONIC KIDNEY DISEASE AS A PREDICTOR OF PRIMARY PERMEABILITY AFTER THE CREATION OF THE VASCULAR ACCESS

Abstract Background and Aims Clinical practice guidelines recommend an arteriovenous fistula (AVF) as the preferred vascular access for hemodialysis. Patency of the arteriovenous access is important for effective hemodialysis. However, maintaining the patency of the AVF remains a challenge. We determined those independent prognostic factors for the patency of the AVF at the time of its creation. Method Cross-sectional study; We include all AVFs performed at the HGUCR in the last 2 decades. Demographic variables (age, sex), etiology of CKD and associated comorbidity were collected. We determine the factors involved in the primary patency of AVFs. Statistical analysis with SPSS 25.0. Categorical variables are expressed as percentages and are compared using the Chi2 test. Quantitative variables are expressed as mean ± standard deviation and the Mann Whitney Student-T/U was used to compare them. Statistical significance for a value of p &amp;lt;0.05. Results 622 AVFs performed in 482 patients were reviewed. 86.8% were autologous. The mean age was 65.4±14 years; 66.6% were male. The most frequent etiologies of CKD were diabetic nephropathy (30.2%), unknown (18%), and glomerulonephritis (16.6%). 91.2% had arterial hypertension (HBP) and diabetes mellitus (DM) 47.9%. 48.7% received antiplatelet therapy and 15.6% anticoagulation prior to the creation of the AVF. 27% presented primary failure. The univariate analysis showed statistical significance for the qualitative variables HTA (p=0.002), treatment with statins (p&amp;lt;0.01) and antiplatelet (p&amp;lt;0.01), and for the quantitative variables fibrinogen (p=0.048), serum phosphorus (p=0.001), CRP (p=0.004), triglycerides (p=0.05), ferritin (p=0.006) and age (p=0.05). When performing a multivariate analysis using logistic regression, HTA (OR: 0.46 95% CI 0.22-0.95 p = 0.036), high phosphorus levels (OR: 1.22 95% CI 1.08-1, 49 p = 0.004) and statin treatment (OR: 0.58 95% CI 0.36-0.96 p = 0.004) are predictors of primary VA failure. Conclusion In our study, HTA and antiplatelet therapy prior to the creation of the VA behave as protective factors for primary failure, with high phosphorus levels being an independent factor for primary failure of AVFs.

MO766EARLY ARTERIOVENOUS FISTULA FAILURE PREDICTION WITH ARTIFICIAL INTELLIGENCE: A NEW APPROACH WITH CHALLENGING RESULTS

Abstract Background and Aims The native arteriovenous fistula is considered the vascular access of preference, since it is directly related to major survival, reduced complications, mortality, and costs. Still, its proper maintenance remains a challenge for nephrologists. A previous study from our group, which used the data of 117 arteriovenous fistulas, led to identify in the multivariable analysis age and vein diameters as predictive factors for early failure. On the other hand, Artificial Intelligence has been established as a tool to identify relationships between variables at deep levels, which might be unseen with more conservative methods like classic statistics. Therefore, through a Machine Learning technique known as Random Forest, the aim is to evaluate the same comorbidity, biological and Doppler ultrasound variables data to identify those with a major relation with the early failure of the native arteriovenous fistula. Method Retrospective cohort study, gathering the same data of the previous study (from 2011 to 2015): survival, ultrasound mapping (morphology and hemodynamics), comorbidities (blood pressure, severe arteriopathy, diabetes, Charlson’s Index), and laboratory (haemoglobin, calcium, phosphorus, PTH, ferritin, PCR). Different Artificial Intelligence algorithms were tested, but the most suited one for the study's aim turned out to be Random Forest. A model was trained, dividing the data in two sets, training and validation, with an 80/20 ratio. The algorithm used 100 decision trees, with a maximum individual depth of 3 levels. The training was made with the variables that represented the 100%, 95%, 90% and 85% of impact in the fistula's maturation from a theresold according to Gini’s Index. Results Age 65.7 (32-88) years, male 59.8%. Hypertension 86.7%, diabetes 50.7% and vascular disease 41.3%. The trained model obtained provided the following results in the evaluation: accuracy 0.82, precision 0.86, AUROC 0.85, F1 0.86 (balance between precision and predictive value). The most relevant variables by decision order were age, phosphorous, PTH, ferritin and calcium. Morphologic and hemodynamic variables such as the vessels diameter, Peak Systolic Velocity, Charlson’s Index or PCR, were also found to be relevant, but in a minor level. Conclusion In comparison with classic statistics, Machine Learning techniques might create a change of paradigm in predictive models for the patency of the vascular access for Haemodialysis. Even though the Artificial Intelligence-based model provided the same relevance for age in maturation failure as traditional models, other findings stand out, like the major participation of variables related with mineral metabolism or inflammation, rather than ultrasound based ones.

The role of stents in hemodialysis vascular access.

Vascular access is the Achilles' heel of dialysis therapy among patient with end stage kidney disease. The development of neointimal hyperplasia and subsequent stenosis is common in vascular access and is associated with significant morbidity. Percutaneous transluminal angioplasty using balloon inflation was the standard therapy of these lesions. However, the balloon-based approaches were associated with poor vascular access patency rate necessitating new inventions. It is within this context that different types of stents were developed in order to improve the overall dialysis vascular access functionality. In this article, we review the available literature regarding the use of stents in treating dialysis vascular access stenotic lesions. Further, we review the major clinical trials of stent use in different anatomic locations and in different clinical scenarios.

A dual-plane approach for surgical treatment of pseudoaneurysm with arteriovenous fistula in hemodialysis patients.

BackgroundWe report the efficacy of a dual-plane approach using a Dufourmentel skin flap with a purse-string suture of the de-epithelized dermis to manage pseudoaneurysm at the vascular access site for hemodialysis.MethodsA retrospective analysis was conducted of 61 patients from 2013 to 2018 with pseudoaneurysms at the arteriovenous fistula or graft who were treated with rhomboid excision, vessel repair with a purse-string suture, and a full-thickness Dufourmentel skin flap. The success rate was defined as the probability of complete wound closure and intact vascular access patency without infection or other complications.ResultsThe success rate was 93.4% at 6 months postoperatively. Complications included newly occurring pseudoaneurysms (n=2), wound dehiscence (n=1) and bleeding (n=1). There were no complications such as stenosis or thrombosis from the procedure.ConclusionsA dual-plane approach using a Dufourmentel skin flap with a purse-string suture for vessel repair was shown to be a favorable option for managing stable, small (diameter <2 cm) pseudoaneurysms without infection, rapid expansion, or patency issues of the vascular access.

COVID-19 and Dialysis Patients: Unsolved Problems in Early 2021.

COVID-19 and Dialysis Patients: Unsolved Problems in Early 2021.

Initial and long-term outcomes of Percutaneous Transluminal Angioplasty for central venous stenosis or occlusion in chronic hemodialysis patients: Analysis of 363 lesions in single center

The purpose of this study was to evaluate the initial and long-term outcomes of Percutaneous Transluminal Angioplasty (PTA) for central venous stenosis or occlusion in chronic hemodialysis patients. A total of 363 central venous lesions (277 stenosis and 86 occluded lesions) of 146 patients were enrolled and analyzed retrospectively; these included 130 de novo lesions and 233 restenosis lesions. The procedural success rate in our cohort was 97.0% (352/363 lesions); success rate for stenosis was significantly higher than that for occluded lesions (99.3% vs. 89.5%, P < 0.001). Complications during PTA procedures occurred in nine lesions (2.5%); however, there were no serious complications. A total of 120 stents were implanted for 111 lesions; the rate of stent placement for occluded lesions was significantly higher than that for stenosis lesions (68.8% vs. 18.4%, P < 0.001). The primary patency of de novo lesions was significantly higher than that of restenosis lesions (P = 0.0004); the assisted patency of de novo lesions at 12 and 36 months were 94.4% and 89.0%, respectively. There was no significant difference of primary patency between balloon angioplasty and stent placement for de novo lesions, however, primary patency after stent placement for restenosis lesions was significantly higher than that after balloon angioplasty (P = 0.001). In conclusion, PTA for central venous stenosis or occlusion was safe procedure with low rate of technical failure. The patency of vascular access in long-term was maintained by the repeated intervention. Stent placement could help prolong the patency period for restenosis lesions.

Abstract No. 545 Effect of multiple patient specific and procedure related factors on patency of dialysis access after declotting procedure

To determine effect of multiple patient specific and procedure related factors on re-thrombosis of arteriovenous dialysis access that underwent declotting procedure by interventional radiology. Consecutive patients that underwent declotting of thrombosed arteriovenous dialysis access were enrolled. Multiple variables including patient’s demographics, comorbidities, and procedure related technical factors were recorded. The effects of these variables on re-thrombosis of the dialysis access during the 12months follow-up period was determined. A total of 111 consecutive patients (age: 61.5 ± 16.9 years, female 47%, male 53%; race: 80% African American, 18% white American, other 2%) were enrolled. Main underlying factors leading to renal failure were determined as DM 13%, HTN 25%, both 41% and other 21%. The access point included AV graft in 78% and AV fistula in 22%. Angiographic/technical declotting was not achieved in 30 (27%) patients at the time of initial declotting procedure. Patients demographic, underlying comorbidities, site or age of the dialysis access was not associated with initially successful angiographic/technical declotting (P > 0.05). In patients with successful declotting (n = 81, 71%), a combination of pharmacologic and mechanical thrombolysis with balloon angioplasty was utilized. 26 (32%) patients had existing vascular stent and in 5 (6%) patients a new stent was deployed. In 9 (11%) patients mechanical thrombectomy device (AngioJet, Argon Cleaner, or Arrow-Trerotola) was used. During the follow-up period (data available in 75 of 81 patients), 27 (36%) patients had re-thrombosis of the access point. The rate of re-thrombosis was significantly higher in AV graft compared to AV fistula (41% vs. 13%, respectively; P < 0.5). Presence of stent or application of thrombectomy device was not associated with a statistically significant difference in re-thrombosis rate or patency period of the access after declotting procedure (rethrombosis rate: stent: 39% vs. no stent: 52%, thrombectomy device: 50% vs. no device: 34%, P > 0.05 for both; rethrombosis time: stent: 77.8 ± 105.5 days vs. no stent: 40.8 ± 43.4 days, thrombectomy device: 46.2 ± 21.6 days vs. no device: 54.3 ± 76.2 days, P > 0.05 for both). Although the presence or placement of vascular stent or application of thrombectomy device could help during initial declotting procedure, they may not be associated with patency rate and interval during the first 12-month follow-up interval.

Effectiveness and safety of repeated percutaneous intervention in an office-based endovascular center in maintaining hemodialysis access.

Percutaneous dialysis access interventions are routinely used to maintain the patency of dialysis access despite the lack of data regarding their long-term effectiveness. This retrospective study was undertaken to study the effectiveness and safety of percutaneous dialysis access interventions in arm fistulas and bridge grafts in an office-based endovascular center. Patients who had a percutaneous dialysis access intervention in their upper extremity access site, performed at a single office-based endovascular center over a nine-year period (2007-2016) were included in this study. The patients' demographic factors, patency, and complications were analyzed. Patients were entered in the study after first percutaneous dialysis access intervention. A total of 298 limbs in 259 patients had 913 procedures carried out over a nine-year period. There were 190 access arteriovenous fistulas and 108 arteriovenous grafts. The two most common arteriovenous fistulas were the brachiocephalic fistula (n = 74, 39%) and radio cephalic fistula (n = 69, 36%). Arteriovenous grafts were most commonly placed in the upper arm (n = 66, 61%) followed by the forearm (n = 42, 39%). The mean overall patency for all limbs was 50.86 months. Arteriovenous fistulas had a significantly longer patency than arteriovenous grafts (51.65 vs. 42.09 months; P = 0.01). In addition, patients with two or more percutaneous dialysis access intervention in their arteriovenous fistula had significantly greater patency than those with only one percutaneous dialysis access intervention (58.5 vs. 7.6 months; hazard ratio 0.41; P = 0.0008). This was not true for the arteriovenous graft group. Women represented 49% of the patient group. Their accesses had shorter patency than men (39.8 vs. 60 months; P = 0.0007). This data support the use of repeated percutaneous dialysis access intervention to maintain long-term patency of dialysis access sites in an office-based endovascular center. Overall, fistulas have longer patency than grafts and women have poorer outcomes as compared to men.