Hemodialysis Arteriovenous Grafts Research Articles

Drug-Coated Balloon and Percutaneous Old Balloon Angioplasty for Hemodialysis Arteriovenous Graft Outlet Stenosis: A Single-Center Randomized Controlled Study

Drug-Coated Balloon and Percutaneous Old Balloon Angioplasty for Hemodialysis Arteriovenous Graft Outlet Stenosis: A Single-Center Randomized Controlled Study

Quantification of steal flow on Doppler ultrasound in patients with arteriovenous graft for hemodialysis.

Arteriovenous fistula (AVF) is the preferred treatment for long-term hemodialysis patients to allow reliable vascular access. Arteriovenous graft (AVG) is monitored using Doppler sonography to check a vessel's condition and predict complications such as steal syndrome. In this study, we developed an analysis algorithm and method to quantify steal syndrome using Doppler sonography. Doppler sonography was used to determine the pattern of anterograde and retrograde flow. The ratio of blood volumes was calculated with a vision analysis software. First, performance of the developed algorithm was validated by comparing it with commercial Doppler sonography data. Doppler sonography was performed for an artificial vessel to analyze the steal flow. A total of 58 patients with steal flow were enrolled in this study. Of these patients, 23 did not have a difference in fingertip temperature between both sides. The median difference in temperature of 35 patients was 0.8°C (range, 0.3-1.9°C). The ratio of retrograde flow volume/antegrade flow volume in patients with the presence of temperature difference was significantly higher compared to that in patients without the temperature difference (p < .001). The ROC curve for the difference in flow volume had an AUC of 0.770. The optimal cutoff of difference in the flow volume between the two groups was 0.24 (sensitivity of 91.4 % and specificity of 52.2%). The flow volume difference was significantly positively correlated to temperature difference (r = 0.487, p < .003). Our algorithm could measure steal flow volume of a bidirectional waveform by antegrade arterial flow and retrograde reversal flow.

USE of IMplanting the Biotronik PassEo-18 Lux drug coated balloon to treat failing haemodialysis arteRiovenous FIstulas and grafts (SEMPER FI Study)

Background: Plain old balloon angioplasty has been the mainstay of treatment for arteriovenous fistula (AVF) stenoses. Recent studies suggest that drug coated balloons (DCB) may significantly reduce re-intervention rates on native and recurrent lesions. The Passeo-18 Lux DCB (Biotronik AG, Buelach, Switzerland) is packaged with a 3.0 µg/mm2 dose of paclitaxel. The hypothesis is that its use provides better target lesion primary patency (TLPP), primary assisted patency (PP), secondary patency (SP) rates and reduces the number of visits for re-intervention in a cohort of patients with stenotic AVF and arteriovenous grafts (AVGs). Methods: The USE of IMplanting the Biotronik PassEo-18 Lux DCB to treat failing haemodialysis arteRiovenous FIstulas and grafts trial (SEMPER FI) was a prospective double-centre, multi-investigator, non-consecutive, non-blinded single-arm study investigating the efficacy and safety of the Passeo-18 Lux DCB in patients with stenotic AVF/AVG lesions between January 2021 and January 2022. Patient demographics, clinical characteristics, vascular access history, operative indications, details and outcomes were collected prospectively. TLPP, circuit access primary patency (CAP), PP, SP and deaths 6- and 12-months post-intervention were studied. Results: Ninety-one patients with 110 lesions were recruited across the two centres. 62.6% ( n = 57) were male with a median age of 63.5 years (SD = 10.5). 62.6% ( n = 57) were taking anti-platelets. Eighty-five AVFs and six AVGs were treated. 60% ( n = 54) of AVFs intervened were radiocephalic. 52.7% ( n = 58) of targeted lesions were juxta-anastomotic stenosis (JAS) and one-third ( n = 33) at the AVF/AVG outflow. 70.9% ( n = 78) of lesions were recurrent. Median time from last intervention was 219 days. 78% of target lesions ( n = 85) and circuits ( n = 70) were patent at 6-months, of which 96.7% ( n = 87) of those requiring assisted intervention were patent. Conclusion: This study shows that the Passeo-18 Lux DCB can be an effective and safe tool in the treatment of failing haemodialysis AVFs/AVGs.

Prospective multicenter study of a novel endovascular venous anastomotic procedure and device for implantation of an arteriovenous graft for hemodialysis.

The traditional sutured venous anastomosis used during arteriovenous graft implantation is associated with a high incidence of subsequent stenosis that is attributed to neointimal hyperplasia. Hyperplasia results from multiple factors, including hemodynamic abnormalities and vessel trauma during implantation. A novel anastomotic connector device was designed to provide an alternative, less traumatic, endovascular venous anastomosis that may ameliorate the clinical challenges associated with a sutured anastomosis. A prospective single-arm multicenter study was performed to evaluate safety and effectiveness of graft implantation using the study device. Patients requiring graft creation and who met the study criteria were enrolled between February 2018 and July 2021 and observed for 6 months. Collected data included baseline characteristics, graft patency and use for hemodialysis, graft interventions, and adverse events. The primary study endpoint was cumulative graft patency, compared to a pre-specified Performance Goal of 75%. Secondary endpoints included primary unassisted patency and serious adverse events, defined as the occurrence of death, graft infection, emergent surgery, significant bleeding, and pseudoaneurysm. A total of 158 patients were enrolled from 10 study sites, among which 144 subjects were evaluable at 6 months and 14 were censored with partial follow-up observation. Three patients died and the graft was abandoned in 12. The primary endpoint was met (p-value < 0.001). By Kaplan Meier survival analysis, cumulative patency was 92.08% with a lower 95% Confidence Bound of 86.98%. Primary unassisted patency was 60.21% with a lower 95% Confidence Bound of 50.84%. Graft infections occurred in six patients, all unrelated to the study device. There were no reports of emergent surgery, significant bleeding or pseudoaneurysm. These results demonstrate that the study device can be used for successful endovascular anastomosis of a vein to a graft for hemodialysis, with acceptable cumulative patency and safety profile at 6 months. ClinicalTrials.gov Identifier: NCT02532621.

Cost-effectiveness analysis of autogenous arteriovenous fistula, arteriovenous graft, and tunneled-cuffed catheter for hemodialysis in patients with end-stage kidney disease in Southern China.

To evaluate the cost-effectiveness of three permanent vascular accesses for maintenance hemodialysis patients from a hospital perspective throughout 5 years, which is the average life expectancy of patients with end-stage kidney disease. We conducted a EuroQol(EQ-5D) questionnaire survey between January 2021 and March 2021 with 250 patients to estimate the health utility of various states in patients under different hemodialysis vascular access. We designed a Markov model and conducted a cost-effectiveness analysis to compare the cost-effectiveness of three hemodialysis vascular access in Guangzhou throughout 5 years. The mean costs were US$44,481 with tunneled-cuffed catheter (TCC), and US$68,952 and US$59,247 with arteriovenous graft (AVG) and autogenous arteriovenous fistula (AVF), respectively. The mean quality-adjusted life-years (QALYs) was 1.41 with TCC, and 2.37 and 2.73 with AVG and AVF, respectively. AVG had an incremental cost-effectiveness ratio (ICER) of US$25,491 per QALY over TCC; AVF had an ICER of -US$26,958 per QALY over AVG. At a willingness to pay below US$10,633.8 per QALY, TCC is likely the most cost-effective vascular access. At any willingness to pay between US$10,633.8 and US$30,901.4 per QALY, AVF is likely the most cost-effective vascular access. These findings illustrate the value of AVF given its relative cost-effectiveness to other hemodialysis modalities. Although AVG costs much more than TCC for slightly higher QALYs than TCC, AVG still has a greater advantage over TCC for patients with longer life expectancy due to its lower probability of death.

Role of Antiplatelet Therapy in Hemodialysis Arteriovenous Graft Secondary Patency Following Successful Percutaneous Thrombectomy.

The purpose of this study was to elicit the relationship of antiplatelet therapy (AP) in maintaining arteriovenous graft (AVG) patency after successful percutaneous pharmacomechanical thrombectomy ("declot"). This was an institutional review board-approved retrospective review of AVG declot procedures between July 2019 and August 2020. AVG characteristics, bleeding complications, anticoagulation and antiplatelet medication regimens, and thrombosis free survival were evaluated. Recurrent time-to-event analysis was performed using a Prentice-Williams-Peterson Gap time model was performed to evaluate AVG thrombosis free survival. A total of 109 declots were technically successful and performed in 63 individual patients. The majority of procedures were performed in upper arm grafts (71%, n = 45). Dual antiplatelet (DAPT) was prescribed after 52 declots (48%), single antiplatelet was prescribed after 36 declots (33%), and anticoagulation was prescribed after 31 declots (28%). Median thrombosis free survival was 37days (range 1-412days) in the no antiplatelet group, 84days (range 1-427days) in the single antiplatelet group, and 93days (range 3-407days) in the DAPT group. Anti-platelet medications trended towards protective of AVG thrombosis in multivariate analysis (hazard ratio 0.84, 95% confidence interval 0.60-1.19); however, this did not reach statistical significance (P = 0.33). A total of 4 major and 5 minor bleeding events occurred. The results of this study support further evaluation of AP therapy in preventing secondary rethrombosis of dialysis AVG.

The related factors to the re-thrombosis of hemodialysis arteriovenous graft after endovascular salvage.

Only a few issues of the related factors to hemodialysis access dysfunction have been evaluated, and the effects of antiplatelets to improve the patency of hemodialysis access remained controversial. Hence, this study aimed to determine the related factors to the re-thrombosis of arteriovenous grafts (AVGs) after endovascular treatment. This retrospective study was conducted at a university-affiliated teaching hospital in Southern Thailand. All patients who underwent hemodialysis with thrombosed AVG, who had pharmacomechanical thrombolysis from January 2016 to December 2018, were enrolled. Post-intervention primary patency was analyzed by the Kaplan-Meier method, and the related factors to the re-thrombosis of AVG were evaluated using logistic regression. A total of 157 patients with thrombosed hemodialysis AVG were enrolled. The most common graft location and configuration was a forearm loop graft (65%). Post-intervention primary patency rate at 1, 3, and 6 months were 79.0%, 67.1%, and 54.0%, respectively. Diabetes mellitus (DM) was a significant related factor for re-thrombosis (hazard ratio [HR], 1.89; 95% confidence interval [CI], 1.20-2.98; p = 0.006). A single antiplatelet after the procedure was a protective factor for re-thrombosis (HR, 0.58; 95% CI, 0.38-0.89; p = 0.013). The median post-intervention primary patency was 15.7 months in the group of single antiplatelet usage, which was better than that of the non-antiplatelet group (p = 0.012). DM and antiplatelet usage were significant related factors to the re-thrombosis of hemodialysis AVG after endovascular salvage.

Prospective, Multicenter Clinical Study of the Covera Vascular Covered Stent in the Treatment of Stenosis at the Graft-Vein Anastomosis of Dysfunctional Hemodialysis Access Grafts

PurposeTo study the use of the self-expanding Covera covered stent for the treatment of stenotic lesions at the venous anastomosis of hemodialysis arteriovenous grafts (AVGs). Materials and MethodsA total of 110 patients with AVG venous anastomotic stenosis of ≥50% and access dysfunction were treated at 14 centers in the United States using percutaneous transluminal angioplasty followed by covered stent placement. The primary end points were 30-day safety and 6-month target lesion primary patency (TLPP). The secondary measures included access circuit primary patency, circuit cumulative patency, and the number of reinterventions through 24 months. ResultsFreedom from a primary safety event at 30 days was 96.4% while the 6-month TLPP rate was 70.3%. Seventy-five patients completed 24-month follow-up (68.2%). The TLPP rates were 54.2% at 365 days and 36.9% at 730 days while the access circuit primary patency rates were 16.7% at 365 days and 7.8% at 730 days (Kaplan-Meier analysis). The access circuit cumulative patency rates were 85.4% at 12 months and 73.6% at 24 months. The number of reinterventions to maintain the patency of the access circuit was 3.6 ± 3.1 at 24 months (1.6 ± 1.9 at the target lesion). ConclusionsUse of the Covera covered stent for hemodialysis graft-vein anastomotic stenosis provided a safe treatment option with a TLPP rate of 70.3% at 6 months and TLPP and cumulative access circuit patency rates of 36.9% and 73.6% at 2 years.

Comparison of Clinical Outcomes in Patients Undergoing a Salvage Procedure for Thrombosed Hemodialysis Arteriovenous Grafts.

BackgroundThe major limitation of arteriovenous graft access is the high incidence of thrombotic occlusion. This study investigated the outcomes of our salvage strategy for thrombosed hemodialysis arteriovenous grafts (including surgical thrombectomy with balloon angioplasty) and evaluated the efficacy of intragraft curettage.MethodsSalvage operations were performed for 290 thrombotic occluded arteriovenous grafts with clinical stenotic lesions from 2010 to 2018. Of these, 117 grafts received surgical thrombectomy and balloon angioplasty from 2010 to 2012 (group A), and 173 grafts received surgical thrombectomy and balloon angioplasty, with an additional salvage procedure using a curette and a graft thrombectomy catheter, from 2013 to 2018 (group B). Outcomes were described in terms of post-intervention primary patency and secondary patency rates.ResultsThe post-intervention primary patency rates in groups A and B were 44.2% and 66.1% at 6 months and 23.0% and 38.3% at 12 months, respectively (p=0.003). The post-intervention secondary patency rates were 87.6% and 92.6% at 6 months and 79.7% and 85.0% at 12 months, respectively (p=0.623). Multivariate Cox regression analysis demonstrated that intragraft curettage was a positive predictor of post-intervention primary patency (hazard ratio, 0.700; 95% confidence interval, 0.519–0.943; p=0.019).ConclusionSurgical thrombectomy and balloon angioplasty showed acceptable outcomes concerning post-intervention primary and secondary patency rates. Additionally, intragraft curettage may offer better patency to salvage thrombotic occluded arteriovenous grafts with intragraft stenosis.

Hemodynamic Analysis on the Anastomosis Angle in Arteriovenous Graft Using Multiphase Blood Model

Numerical analysis was performed for the effect of the venous anastomosis angle in a forearm arteriovenous graft for hemodialysis using a multiphase blood model. The geometry of the blood vessel was generated based on the patient-computed tomography data. The anastomosis angles were set at 15°, 30°, and 45°. The hematocrit was set at 34%, 45%, and 58%. The larger anastomosis angle, high wall shear stress area &gt;11 Pa, increases to the side of the vein wall away from the anastomosis site. Further, the relatively low wall shear stress area, &lt;3 Pa, occurs near the anastomosis site in larger anastomosis angles. Therefore, the effect of high wall shear stress has advantages in the vicinity of the anastomosis, as the anastomosis angle is larger, but disadvantages as the distance from the anastomosis increases. Moreover, patients with low hematocrit are advantageous for WSS area.

The secondary patency after patch venoplasty versus balloon venoplasty in management of neointimal hyperplasia of the venous anastomosis of thrombosed arteriovenous grafts for hemodialysis

Background The pathogenesis of neointimal hyperplasia associated with hemodialysis arteriovenous (AV) grafts is complex and likely involves surgical manipulation of the tissues, material biocompatibility, and mechanical factors. Both surgical and radiological interventions for stenosed and thrombosed AV graft have been described aiming at the optimal restoration of morphology and function. Aim To compare the secondary patency after patch venoplasty and balloon venoplasty in management of neointimal hyperplasia of the venous anastomosis of AV graft for dialysis. Patients and methods This is a double-armed randomized prospective study that was carried out at Ain Shams University hospitals for 2 years. A total of 20 patients with thrombosed synthetic AV graft were enrolled in this study. The first group (10 patients) was treated with patch venoplasty, and the second group (10 patients) with balloon venoplasty adjunctive after surgical thrombectomy. Results Graft patency at 6-month and 12-month follow-up was 90 and 70% for the balloon angioplasty group versus 60 and 40% for the surgical patch venoplasty group (P=0.3 and 0.37, respectively). Conclusion In the present study, the outcome of balloon venoplasty was better than and patch venoplasty for thrombosed AV grafts. In addition to better graft patency, balloon venoplasty offers the advantage of shorter operative time and lower morbidity. Further studies with a large sample size and multicentric cooperation are required to confirm the present findings.

Single Asian Center Experience Using the Flixene™ Early Cannulation Graft for Hemodialysis Access Creation

The aim of this study was to review the efficacy of the Flixene™ (Atrium™, Hudson, NH, USA) hemodialysis arterio-venous graft (AVG) in a multiethnic Asian cohort of patients with end-stage renal failure (ESRF). Primary outcome was graft primary patency rate and secondary end points included graft usability, time to cannulation, reinterventions required for access salvage, complications, and patient mortality. Single-center, single-arm, multi-investigator nonrandomized retrospective study. Patients with ESRF who underwent Flixene™ graft implantation over a two-year period (January 2017 - December 2018) were included to allow at least one-year follow-up. Demographics, procedural and follow-up data were collected from the hospital electronic medical records. About 48 patients (49 AVG) were included. There were 24 (50%) men; mean age 63.7 (IQR 58.2-71.3) years. Technical success rate was 45/49 (91.8%); 4/49 (8.2%) AVG created did not reach cannulation. 11/49 (22.4%) and 28/49 (57.1%) achieved cannulation within 1 and 2weeks, respectively. 6- and 12- month primary patencies were 33.5% and 19.6%, respectively. Primary-assisted patency rates were 46.6% and 29.6% at the same time intervals. Secondary patency rate was 77.6% and 63.9% at 6 and 12months, respectively. There were 6 (12.2%) graft infections requiring explant and one-year mortality was 14%. Our experience with the Flixene™ early cannulation graft is comparable with other AVGs in terms of patency and infection rates. However, early cannulation rates are lower than in other case series.

The Cleaner XT™ Device as an Endovascular Adjunct for Pharmacomechanical Thrombolysis of Thrombosed Arteriovenous Fistulas and Grafts

Objective: This paper documents our experience using the Cleaner XT™ device (Argon Medical Devices, Plano, TX, USA) for pharmacomechanical thrombolysis (PMT) of thrombosed haemodialysis arteriovenous grafts (AVG) and fistulas (AVF).Materials and Methods: This was a retrospective case series (n=17) over six months at Singapore General Hospital. We evaluated demographics, procedural data, technical and procedural success, patency rates and complications.Results: There were 8 (47%) males and the patients’ mean age was 66 (± 5.7) years. The mean age of AVF/AVG was 1605 (± 1099) days. All procedures were performed under local anaesthetic. PMT was performed within a mean time of 40 (±34.3) hours from the presentation. Technical, clinical and procedural success was 15/17 (88%). The thrombolysis agents used were tissue plasminogen activator (52.9%) and urokinase (41.2%). Mean primary patency time was 114 (± 116) days, with a 65% 1-month and 47% 3-month primary patency rates. The mean secondary patency time was 155 (±132) days, with 76% one-month and 65% three-month secondary patency rates, respectively. AVF rupture occurred in 3/17 (18%) cases but did not involve loss of the access circuit.Conclusion: The Cleaner XT™ device is a safe, minimally invasive endovascular tool for PMT in thrombosed AVF/AVG, with relatively high success and low complication rates.

Short- to midterm results of early cannulation arteriovenous grafts (Gore® ACUSEAL) for hemodialysis: Experience with the ACUSEAL in a Japanese cohort.

In patients without suitable vasculature for autologous arteriovenous fistula, vascular access using a prosthetic graft is an option for hemodialysis. Gore® ACUSEAL Vascular graft is an early cannulation arteriovenous graft (AVG) that allows early puncture within 24 h after surgery. We aimed to report the outcomes of using this graft in patients from a single center. This study included 113 patients who underwent surgery for a new AVG using ACUSEAL, between December 2015 and December 2017, and were followed up. The primary outcomes were primary patency, assisted-primary patency, and secondary patency. Secondary outcomes were postoperative complications such as graft infection and steal syndrome. Of the 113 patients, 60 were male and 53 were female. The average age was 74.4 ± 10.7 years. We could cannulate 69.1% of patients within 24 h. The average follow-up period was 20.1 ± 10.8 months. The primary patency rates after 3 months, 6 months, and 1 year were 76.2%, 60.4%, and 33.8%, respectively. The assisted-primary patency rates after 3 months, 6 months, and 1 year were 88.8%, 73.2%, and 58.9%, respectively. The secondary patency rates after 3 months, 6 months, and 1 year were 100%, 100%, and 98.8%, respectively. Fourteen patients (12.4%) developed graft infection and two patients (1.8%) developed steal syndrome. In our study, ACUSEAL showed satisfactory patency and acceptable complication rates in the short to medium term, similar to previous studies. ACUSEAL is beneficial for surgeons who are familiar with using AVG and for medical staff who control bleeding after dialysis. However, due to the large outer diameter of the graft, surgical wounds might become dehiscent, and careful designing of the subcutaneous graft route is necessary. It might be possible to reduce the rate of graft infection by planning the site and skin incision.

Total Resection of Infected Peripheral Hemodialysis Grafts Has a Favorable Impact on Outcomes

Surgical resection could be an eradication treatment for patients with infected hemodialysis arteriovenous grafts (AVGs). This study aimed to investigate the outcomes of 3 surgical methods, including total resection, subtotal resection, and revision. The patients who underwent surgical excision of infected AVGs performed at a single center from August 2012 to March 2019 were retrospectively analyzed. The following 3 surgical methods were used in our study: revision, subtotal resection, and total resection. Patients' demographics, medical history, perioperative details, reconstruction time, and follow-up data were collected. The outcomes including perioperative complications (within 30days), mortality, reinfection rate of AVGs, with new access reconstruction or not, and the outcomes between reconstruction and nonreconstruction in the follow-up period were evaluated. Forty-one patients had infected AVGs in our study. Patients' mean age was 62years, and 65.9% of the patients were female. The mean duration from the time of diagnosis to the operation was 14.4days. Signs and symptoms at presentation included fever (51.2 %), swelling (43.9%), pain (58.5%), erythematous change (92.7%), and more severe features, such as altered consciousness (14.6%) and hypotension (12.2%). The pathological changes in the infected grafts included bleeding (29.3%), pus formation (73.2%), pseudoaneurysm (26.8%), and graft exposure (17.1%). Wound and graft cultures revealed an infectious etiology with fungi (7.3%), Pseudomonas aeruginosa (12.2%), Enterococcus spp. (2.4%), and Staphylococcus spp. (58.5%), with methicillin-resistant Staphylococcus aureus accounting for only 7.3%. Total resection, subtotal resection, and revision surgery were performed in 17.1%, 63.4%, and 19.5% of patients, respectively. Seven patients with complications required reoperation (17.1%), and adhesion ileus and hospital-acquired pneumonia occurred in only 2.4% and 7.3% of patients, respectively. During follow-up, most patients (82.9%) had reconstruction of the peripheral hemodialysis access with mean time of 64.3 (range: 21-92) days; mean time of use of new access was 90.5days; and mean time of removal of catheter was about 106.3days. Mortality rates in patients without and with reconstructed AV access during follow-up were 50% and 18%, respectively (P<0.004). Eight cases (19.5%) had recurrence of AV access infections during follow-up; of these, 2 had revision surgery and 6 had subtotal resection. However, no patient with total resection had recurrent infections. The total resection group had no recurrent infection compared to the subtotal and revision groups. In addition, patients with reconstruction of peripheral hemodialysis access had a low mortality rate during the follow-up period.

Reduced patency in left-sided arteriovenous grafts

For decades, arteriovenous access grafts for hemodialysis have been saddled with poor long-term utility and few clinical predictors of success. Traditionally, sidedness of access creation has been based on extremity dominance, ignoring any possible contribution of laterality to patency. The novel hypothesis that laterality might play a role in the patency of arteriovenous grafts was tested in this thoughtful preclinical study.

Drug-coated balloon versus conventional balloon angioplasty of hemodialysis arteriovenous fistula or graft: A systematic review and meta-analysis of randomized controlled trials.

BackgroundRestenosis remains a significant problem in endovascular therapy for hemodialysis vascular access. Drug-coated balloon (DCB) angioplasty decreases restenosis in peripheral and coronary artery diseases. The aim of this systematic review and meta-analysis is to assess the patency outcomes following DCB angioplasty, as compared to conventional balloon (CB) angioplasty for the stenosis of hemodialysis vascular access.MethodsA comprehensive search in the MEDLINE, EMBASE, and CENTRAL databases was conducted in order to identify eligible randomized controlled trials evaluating DCB angioplasty for hemodialysis vascular access dysfunction. The primary endpoint was the 6-month target lesion primary patency and the secondary endpoints were 12-month target lesion primary patency and procedure-related complications. Risk ratios (RR) were pooled and relevant subgroups were analyzed separately.ResultsEleven randomized controlled trials comprised of 487 patients treated with DCB angioplasty and 489 patients treated with CB angioplasty were included. There were no significant differences in the target lesion primary patency at 6 months [RR, 0.75; 95% confidence interval (CI), 0.56, 1.01; p = 0.06] and at 12 months (RR 0.89; 95% CI, 0.79, 1.00; p = 0.06). The absence of benefit for the DCB group remained, even in the arteriovenous fistula subgroup or the subgroup of studies excluding central vein stenosis. The risk of procedure-related complication did not differ between the two groups (RR 1.00; 95% CI 0.98, 1.02; p = 0.95).ConclusionDCB angioplasty did not demonstrate significant patency benefit for the treatment of hemodialysis vascular access dysfunction. Wide variations in patency outcomes across studies were noted. Further studies focusing on specific types of access or lesions are warranted to clarify the value of DCB for hemodialysis vascular access. (PROSPERO Number CRD42019119938)

Hemodialysis arterio-venous graft design reducing the hemodynamic risk of vascular access dysfunction

Although arterio-venous grafts (AVGs) represent the second choice as permanent vascular access for hemodialysis, this solution is still affected by a relevant failure rate due to graft thrombosis, and development of neointimal hyperplasia (IH) at the distal vein. As a key role in these processes has been attributed to the abnormal hemodynamics establishing in the distal vein, the optimization of AVGs design aimed at minimizing flow disturbances would reduce AVG hemodynamic-related risks. In this study we used computational fluid dynamics to investigate the impact of alternative AVG designs on the reduction of IH and thrombosis risk at the distal venous anastomosis. The performance of the newly designed AVGs was compared to that of commercially available devices. In detail, a total of eight AVG models in closed-loop configuration were constructed: two models resemble the commercially available straight conventional and helical-shaped AVGs; six models are characterized by the insertion of a flow divider (FD), straight or helical shaped, differently positioned inside the graft. Unfavorable hemodynamic conditions were analyzed by assessing the exposure to disturbed shear at the distal vein. Bulk flow was investigated in terms of helical blood flow features, potential thrombosis risk, and pressure drop over the graft.Findings from this study clearly show that using a helically-shaped FD located at the venous side of the graft could induce beneficial helical flow patterns that, minimizing flow disturbances, reduce the IH-related risk of failure at the distal vein, with a clinically irrelevant increase in thrombosis risk and pressure drop over the graft.

Balloon Angioplasty Versus Stenting for the Treatment of Failing Arteriovenous Grafts: A Meta-Analysis

Introduction - to assess the outcomes of plain balloon angioplasty versus stenting for the treatment of failed or malfunctioning haemodialysis arteriovenous grafts (AVGs) for chronic haemodialysis. Methods - A systematic search of the literature was undertaken using PUBMED, EMBASE and Cochrane databases from January 2000 to September 2016 for articles comparing balloon angioplasty versus stenting in the management of failed or malfunctioning haemodialysis AVGs. Results are reported as the odds ratio (OR) and 95% confidence interval (CI). Results - The search identified eight studies (1051 patients). Balloon angioplasty alone was used in 521 patients (49.6%) and stenting in 530 patients (50.4%). At the time of the endovascular re-intervention, the mean life of AVGs was 807.7±115.4 days for the balloon angioplasty and 714.2±96.3 days for the stenting group (p=0.92). All AVGs were located in the arm. Most procedures (98.1%) were performed across the venous anastomosis, while 88% of the patients in the stenting group received a stent-graft. The technical success rate was significantly higher in the stenting group (OR 0.16, 95% CI 0.08 to 0.31, p<0.001). At 12 months, loss of primary and secondary patency was significantly higher in patients undergoing plain balloon angioplasty compared to stenting, (OR 3.54, 95% CI 2.18 to 5.74, p<0.001) and (OR 1.82, 95% 1.17 to 2.82, p=0.008), respectively. Conclusion - Stenting is associated with better technical success and patency rates compared to plain angioplasty in treating failed or malfunctioning haemodialysis AVGs and thus it should be considered as the therapeutic strategy of choice.

Endovascular thrombectomy versus open surgical thrombectomy for thrombosed arteriovenous hemodialysis graft

Objective: The aim of this study was to investigate the procedure success rate, one-year primary patency rate, one-year secondary patency rate, and complications compared between endovascular therapy and open surgical thrombectomy for treatment of thrombosed arteriovenous hemodialysis graft.Methods: This retrospective chart review included patients with thrombosed arteriovenous hemodialysis graft who were treated at the Division of Vascular Surgery, Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand during January 2012 to December 2016. Demographic, graft type, time before treatment, thrombus removal technique, additional technique, procedure success rate, operative, primary and secondary patency, follow-up time, and complication data were collected.Results: Seventy-four thrombosed dialysis grafts were included. Twenty-five and 49 grafts underwent endovascular therapy and open surgical thrombectomy, respectively. There was no significant difference in demographic data, graft type, or adjunct procedure between groups. The procedure success rate was 92% and 98% in the endovascular group and thrombectomy group, respectively (p=0.262). The one-year primary patency rate was 26% in the endovascular group, and 33% in the thrombectomy group (p=0.054). One-year secondary patency rate was 82.6% in the endovascular group, and 56.3% in the thrombectomy group (p=0.122).Conclusion: No significant differences were observed between groups for procedure success rate or 1-year primary patency rate; however, the one-year secondary patency rate in the endovascular group was significantly better than in the thrombectomy group. No difference in complications was observed between groups.