Hemodialysis Grafts Research Articles

Evaluation of efficacy of open thrombectomy for recently thrombosed arteriovenous fistulae and synthetic grafts for hemodialysis

Evaluation of efficacy of open thrombectomy for recently thrombosed arteriovenous fistulae and synthetic grafts for hemodialysis

Efficacy and safety of early cannulation arteriovenous grafts for hemodialysis

A total of 309 (138 males and 171 females) end-stage renal disease patients who underwent implantation of early cannulation arteriovenous grafts (Acuseal) for hemodialysis in Nanfang Hospital, Southern Medical University between December 2016 and May 2021 were retrospectively included. The age of patients was (61.5±10.3) years. There were 244 patients (119 males and 125 females) who received regular follow-up. During the follow-up period, 24 patients died. Perioperative complications included graft infection (4.5%, 11/244), hematoma (4.5%, 11/244) and steal syndrome (4.1%, 10/244). No seroma or anastomotic rupture occurred. The rates of the first postoperative puncture time within 24 h, 48 h and 72 h after implantation were 42.2%(103/244), 32.4% (79/244) and 16.4% (40/244), respectively. The Kaplan-Meier survival analysis showed that the primary patency rates at 6 months and 12 months were 66.5% and 48.4%, respectively, and the secondary patency rates at 6 months and 12 months were 96.7% and 91.8%, respectively. The current study indicates that the Acuseal graft is safe for vascular access in patients requiring hemodialysis, with satisfactory patency and acceptable complication rates at 1-year follow-up.

Outcome of upper limb arteriovenous prosthetic graft versus lower limb arteriovenous access for hemodialysis in patients with exhausted vascular accesses

Outcome of upper limb arteriovenous prosthetic graft versus lower limb arteriovenous access for hemodialysis in patients with exhausted vascular accesses

517 Treatment of Steal Syndrome from a Brachioaxillary Haemodialysis Graft

517 Treatment of Steal Syndrome from a Brachioaxillary Haemodialysis Graft

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.

Axillary necklace graft salvage of a locally infected Haemodialysis with Reliable Outflow (HeRO®) graft.

A 48-year-old patient presented 4 months after insertion of a right sided Haemodialysis with Reliable Outflow (HeRO®, Merit Medical) graft with a discharging abscess at the site of the brachial artery anastomosis. There was localised involvement of the arterial Gore® Acuseal inflow graft that necessitated its removal. The venous outflow component was thought salvageable as infection was well localised to the region of the antecubital fossa. Alternative access options were limited so we sought to preserve the venous outflow portion of the patient's original graft - minimising tissue damage and avoiding the need for a dialysis line. The infected arterial graft was excised, leaving behind the original SuperHero® connector and venous graft. A left sided tunnelled axillary necklace technique was utilised to restore arterial inflow. After a four-day recovery, the patient went on to successfully resume their usual haemodialysis regimen without any complications. Convalescent imaging, repeat blood cultures, and monitoring of inflammatory markers showed no signs of residual infection at 6 weeks. The originality of this case was the way in which an axillary necklace inflow graft was connected to the pre-existing venous outflow portion of the HeRO® haemodialysis graft system, allowing the excision of the infected inflow graft at the brachial anastomosis. This technique could be viewed as an effective salvage procedure as it allowed the venous outflow portion of the original graft to remain in situ, minimised tissue damage and enabled the patient to swiftly resume haemodialysis without the need for a line.

Quality assurance in surgical trials of arteriovenous grafts for haemodialysis: A systematic review, a narrative exploration and expert recommendations.

Introducing new procedures and challenging established paradigms requires well-designed randomised controlled trials (RCT). However, RCT in surgery present unique challenges with much of treatment tailored to the individual patient circumstances, refined by experience and limited by organisational factors. There has been considerable debate over the outcomes of arteriovenous grafts (AVG) compared to AVF, but any differences may reflect differing practice and potential variability. It is essential, therefore, when considering an RCT of a novel surgical procedure or device that quality assurance (QA) is defined for both the new approach and the comparator. The aim of this systematic review was to evaluate the QA standards performed in RCT of AVG using a multi-national, multi-disciplinary approach and propose an approach for future RCT. The methods of this have been previously registered (PROSPERO: CRD420234284280) and published. In summary, a four-stage review was performed: identification of RCT of AVG, initial review, multidisciplinary appraisal of QA methods and reconciliation. QA measures were sought in four areas - generic, credentialing, standardisation and monitoring, with data abstracted by a multi-national, multi-speciality review body. QA in RCT involving AVG in all four domains is highly variable, often sub-optimally described and has not improved over the past three decades. Few RCT established or defined a pre-RCT level of experience, none documented a pre-trial education programme, or had minimal standards of peri-operative management, no study had a defined pre-trial monitoring programme, and none assessed technical performance. QA in RCT is a relatively new area that is expanding to ensure evidence is reliable and reproducible. This review demonstrates that QA has not previously been detailed, but can be measured in surgical RCT of vascular access, and that a four-domain approach can easily be implemented into future RCT.

First-in-human feasibility study of the aXess graft (aXess-FIH): 6-Month results.

The creation of an arteriovenous fistula (AVF) is considered the most effective hemodialysis (HD) vascular access. For patients who are not suitable for AVF, arteriovenous grafts (AVGs) are the best access option for chronic HD. However, conventional AVGs are prone to intimal hyperplasia, stenosis, thrombosis, and infection. Xeltis has developed an AVG as a potential alternative to currently available AVGs based on the concept of endogenous tissue restoration. The results of the first 6-month follow-up are presented here. The aXess first-in-human (FIH) study [NCT04898153] is a prospective, single-arm, multicenter feasibility study that evaluates the early safety and performance of the aXess Hemodialysis Graft. A total of 20 patients with end-stage renal disease were enrolled across six European investigational sites. At 6-months follow-up, all grafts were patent with primary and secondary patency rates were 80% and 100%, respectively. Three patients required a re-intervention to maintain graft patency, while one re-intervention was required to restore patency. One graft thrombosis and zero infections were reported. The expected advantages of the novel aXess Hemodialysis Graft over conventional AVGs would be evaluated by the analysis on long-term safety and effectiveness during the 5-year follow-up of the currently ongoing trial.

Challenges and potential solutions to enrollment in a clinical trial of arteriovenous fistula vs arteriovenous graft vascular access strategy

This article presents the rationale, challenges, and adaptive strategies employed during the initiation and execution of the arteriovenous (AV) access trial—a multicenter randomized controlled trial (RCT) comparing AV fistulas and AV grafts for hemodialysis in older adults with major comorbidities. Motivated by shifts in epidemiologic landscapes and evolving guidelines moving away from a fistula-first approach and to more patient-centric approaches, the objective of this randomized controlled trial was to fill critical knowledge gaps in determining the optimal vascular access for this complex patient population. We outline the challenges encountered in patient recruitment along with measures employed to overcome these obstacles in recruitment. We emphasize the pivotal role of continuous research in overcoming these challenges, underscoring its necessity to achieve a thorough comprehension of optimal vascular access strategies for this complex patient population.

Multicenter Randomized Controlled Trial of APERTO-Paclitaxel Drug-Eluting Balloon Angioplasty Versus Standard Percutaneous Transluminal Angioplasty in Dysfunctional Hemodialysis Grafts and Native Fistulae.

to assess the safety and efficacy of APERTO-Paclitaxel-coated balloon angioplasty versus standard angioplasty for the treatment of dysfunctional hemodialysis shunts and native arteriovenous fistulae. consecutive patients with dysfunctional dialysis related to underlying efferent vein stenosis were included and randomized 1:1 to either APERTO-paclitaxel drug-coated balloon (study arm) or standard percutaneous transluminal angioplasty (control arm). Primary endpoint is time from treatment until dialysis access dysfunction according to standardized Kidney Disease Outcomes Quality Initiative (KDOQI)-guidelines and assessed by Kaplan-Meier survival curves and tested for significance with log-rank analysis. Secondary endpoints include device, technical, and clinical success of the index angioplasty procedure. The study included 103 patients (n=51 study-group) with a de novo (n=33) dysfunctional native arteriovenous fistula (n=79) in the forearm (n=60). The majority of included patients were male with a mean age of 69.8 years, presenting with a dysfunctioning autologous arteriovenous fistula in the forearm. Device-related complications did not occur in any of the included patients. Functional hemodialysis access without need for re-intervention at 1 year after index procedure was found in n=10 (19.6%) and n=5 (9.6%) of patients treated with, respectively, paclitaxel drug-coated balloon and percutaneous transluminal angioplasty (p=0.612). A nonsignificant benefit of paclitaxel drug-coated balloon (n=5; 25%) over percutaneous transluminal angioplasty (n=1; 11%) was found (p=0.953) in de novo lesions in autologous fistulas. APERTO-paclitaxel drug-coated balloon is a safe balloon catheter to manage dysfunctional hemodialysis access; however, longer period of adequate hemodialysis circuit functioning after endovascular index stenosis treatment, using APERTO-paclitaxel drug-coated balloon versus percutaneous transluminal angioplasty could not be demonstrated. APERTO-paclitaxel drug-coated balloon catheter is a safe device to manage dysfunctional hemodialysis access. Compared to conventional angioplasty balloon, the APERTO drug-coated balloon will not result in longer period of adequate hemodialysis circuit functioning. A non-significant benefit of APERTO drug-coated balloon was found in de novo lesions in autologous fistulas.

Quality assurance in surgical trials of arteriovenous grafts for haemodialysis: protocol for a systematic review

IntroductionDecisions regarding the optimal vascular access for haemodialysis patients are becoming increasingly complex, and the provision of vascular access is open to variations in systems of care as well as...

Study protocol of a prospective single-arm multicenter clinical study to assess the safety and performance of the aXess hemodialysis graft: The pivotal study.

Arteriovenous grafts (AVGs) are used for patients deemed unsuitable for the creation of an autogenous arteriovenous fistula (AVF) or unable to await maturation of the AVF before starting hemodialysis. However, AVGs are prone to infection and thrombosis resulting in low long-term patency rates. The novel aXess Hemodialysis Graft consists of porous polymeric biomaterial allowing the infiltration by cells and the growth of neotissue, while the graft itself is gradually absorbed, ultimately resulting in a fully functional natural blood vessel. The Pivotal Study will examine the long-term effectiveness and safety of the aXess Hemodialysis Graft. The Pivotal Study is a prospective, single-arm, multicenter study that will be conducted in 110 subjects with end-stage renal disease who are not deemed suitable for the creation of an autogenous vascular access. The primary efficacy endpoint will be the primary patency rate at 6 months. The primary safety endpoint will be the freedom from device-related serious adverse events at 6 months. The secondary endpoints will include the procedural success rate, time to first cannulation, patency rates, the rate of access-related interventions to maintain patency, the freedom from device-related serious adverse events and the rate of access site infections. Patients will be followed for 60 months. An exploratory Health Economic and Outcomes Research sub-study will determine potential additional benefits of the aXess graft to patients, health care institutions, and reimbursement programs. The Pivotal study will examine the long-term performance and safety of the aXess Hemodialysis Graft and compare the outcome measures with historical data obtained with other graft types and autogenous AVFs. Potential advantages may include superior long-term patency rates and lower infection rates versus currently available AVGs and a shorter time to first cannulation compared to an autologous AVF. As such, the aXess Hemodialysis Graft may fulfill an unmet clinical need in the field of hemodialysis access.

Management of infected arteriovenous grafts for haemodialysis: Outcomes and strategies using a novel objective scoring system.

In haemodialysis patients with exhausted autogenous options, prosthetic arteriovenous grafts (AVGs) are frequently utilised as tertiary vascular access. However, the prosthetic nature of AVGs precipitates an increased risk of infection which may translate to excess morbidity and life-threatening complications. The current evidence remains divided on the optimal treatment strategy for arteriovenous graft infections (AVGi) with arguments for conservative management by antibiotics, salvaging with graft revision or total/subtotal excision. To address this gap, we assessed the outcomes of AVGi patients treated in our institution, developing an AVGi severity classification model and a proposed treatment algorithm to guide AVGi management. We conducted a single centre retrospective review of outcomes of patients with AVGi managed either by sole antibiotics therapy, graft revision or surgical excision between June 2016 and May 2021. Outcomes of AVGi patients across differing treatment groups were compared, including 1-year mortality, 6-month and 1-year functional vascular access. We also analysed the outcomes of tunnelled haemodialysis lines (THL), which were used as a temporary vascular access in several AVGi patients in our study. A total of 34 AVGi patients were managed within that time frame and included in the study (5 conservatively management by antibiotics, 5 graft revisions and 24 surgical excision) with a mean age of 60.4 ± 14.4 years (67.6% males). Overall 1-year mortality was 14.7%. A 6-month functional vascular access status across the three groups stood at 60%, 60% and 10% while 1-year functional vascular access status was 60%, 75% and 42% respectively. When clinically appropriate, conservative management by antibiotics or salvage/graft revision can present as prudent AVGi treatment options. The adoption of our proposed severity classification system and treatment algorithm provides a more thorough objective assessment of the infection and helps guide the clinical decision-making process.

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.

Comparitve study between synthetic Brachio - axillary and brachio – vena comitans grafts for hemodialysis

Comparitve study between synthetic Brachio - axillary and brachio – vena comitans grafts for hemodialysis

Prevalence of JC and BK Polyomavirus Infection in Patients with Chronic Kidney Disease in the State of Pará, Brazil.

The polyomaviruses that infect humans, JC virus (JCV) and BK virus (BKV), can establish persistent infections in the cells that make up the renal system, causing nephritis and BKV-associated nephropathy in up to 10% of renal transplant patients, and of these, 90% lose the graft and return for hemodialysis. This study aimed to determine the prevalence of polyomaviruses (PyV) in the population with chronic kidney disease (CKD), classified into three groups (conservative, dialysis, and transplanted) and a control group. Urine samples were collected from 290 individuals, including 202 patients with CKD and 88 from the control group. PyV screening was performed by PCR amplification of a fragment of the VP1 region, and the JCV and BKV species were distinguished through enzymatic digestion with the restriction endonuclease BamHI from the amplification of a TAg region. All amplification products were visualized on a 3% agarose gel. The prevalence of PyV infection was correlated with clinical-epidemiological variables using the chi-squared and Fisher's exact tests. In the group with CKD, the prevalence of PyV was 30.2%, a higher rate being observed in conservative patients (36.66%; 22/60), followed by dialysis patients (30.48%; 25/82), and transplanted patients (20%; 12/60). In the control group, the prevalence was 46.59% (41/88). The differentiation between species revealed that JCV was present in 77.8% and BKV in 22.2% of the group with CKD. The prevalence of infection was higher in male patients (59.32%), whose most common pathology was systemic arterial hypertension (35.59%). In the group of transplanted patients, there was a statistically significant association between infection and the use of the immunosuppressant azathioprine (p = 0.015). The prevalence of PyV infection was higher in the control group than in the group with CKD, being predominant in males and in patients with systemic arterial hypertension.

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.

A Single-Center Experience with Forearm Arteriovenous Loop Grafts for Hemodialysis

Autogenous arteriovenous fistula (AVF) remains the standard of hemodialysis (HD) access; however, it cannot be reasonably obtained in all patients. For patients with contraindications to AVFs, prosthetic arteriovenous graft (AVG) remains an alternative. AVGs are plagued by high failure rates; however, there is a paucity of literature examining this. This study aims to examine a single-center review of outcomes of forearm loop AVGs in patients requiring HD access. A single institution, retrospective chart review was completed from 2012 to 2019, including demographics, end-stage renal disease etiology, brachial vessel diameters, and comorbidities. Logistic regression and Cox proportional hazard models were evaluated. Outcomes were defined as primary patency (time elapsed from graft creation until it was utilized as the patient's primary access), primary-assisted patency (time from primary access to intervention to maintain patency), and functional patency (time from graft placement until graft failure). Additionally, multinomial regression models were used to evaluate associations with categorical number of required interventions. Ninety-eight patients [mean age 61.8 (13.9) years, 42.9% female] were identified as having brachial artery to brachial vein AVG creation during the study period, of which 75% achieved primary patency. Primary-assisted patency was 0.36 [standard error (SE) 0.07] at 6months and 0.12 (SE 0.05) at 1year. Functional patency was 0.75 (SE 0.07) at 6months and 0.43 (SE 0.09) at 1year. No association between preoperative vessel diameters and primary-assisted or functional patency was observed. Interestingly, there was a significant negative association between previous ipsilateral access and achievement of primary patency with a 60% decrease in odds of achieving primary patency in patients with previous ipsilateral access [odds ratio 0.4, 95% confidence interval (CI) 0.1-0.9, P=0.03]. There was also noted to be a significant association between the presence of an ipsilateral catheter and increased risk of subsequent abandonment of the AVG (hazard ratio 2.6, 95% CI 1.1-5.8, P=0.02). Prosthetic forearm loop AVGs remain hindered in their utility as they show high rates of graft failure within a year of creation. A significant patient-specific factor leading to this was not clearly demonstrated. As guidelines change regarding the nature of dialysis access for patients on HD, these results draw into question the utility of prosthetic forearm loop grafts in patients requiring long-term HD access.

Functioning tailor-made 3D-printed vascular graft for hemodialysis.

The two ends of arteriovenous graft (AVG) are anastomosed to the upper limb vessels by surgery for hemodialysis therapy. However, the size of upper limb vessels varies to a large extent among different individuals. According to the shape and size of neck vessels quantified from the preoperative computed tomography angiographic scan, the ethylene-vinyl acetate (EVA)-based AVG was produced in H-shape by the three-dimensional (3D) printer and then sterilized. This study investigated the function of this novel 3D-printed AVG in vitro and in vivo. This 3D-printed AVG can be implanted in the rabbit's common carotid artery and common jugular vein with ease and functions in vivo. The surgical procedure was quick, and no suture was required. The blood loss was minimal, and no hematoma was noted at least 1 week after the surgery. The blood flow velocity within the implanted AVG was 14.9 ± 3.7 cm/s. Additionally, the in vitro characterization experiments demonstrated that this EVA-based biomaterial is biocompatible and possesses a superior recovery property than ePTFE after hemodialysis needle cannulation. Through the 3D printing technology, the EVA-based AVG can be tailor-made to fit the specific vessel size. This kind of 3D-printed AVG is functioning in vivo, and our results realize personalized vascular implants. Further large-animal studies are warranted to examine the long-term patency.

Treatment of intragraft stenosis in hemodialysis grafts with Supera stents: A retrospective study.

To report the patency rates after implantation of an interwoven nitinol stent to salvage failing arteriovenous grafts (AVGs) caused by intragraft stenoses. Between May 2018 and May 2020, 21 Supera stents were placed in 20 patients (18 women; mean age: 79.9 years) who had a failing AVG due to repeat intragraft stenoses. Recurrent AVG dysfunction with same intragraft stenosis within 3 months after first time angioplasty was a criterion for stenting. Those with concurrent treatment for other lesions were excluded. The technical success rate was 100%. Intragraft stenoses were treated at a median of 19.7 (interquartile range: 6-36) months after graft creation. Access circuit primary patency rates after stent placement were 84% and 35% at 6 and 12 months, respectively. Access circuit secondary patency rates were 100% at 6 and 12 months and 89% at 18 months. Only one patient presented with graft failure due to proximal drainage vein occlusion. The target lesion patency rates were 100% at 6 months and 75% at 12 months. The rate of reintervention for intragraft lesion was 0.15 procedures per year. Stent distortion did not occur under regular cannulation. The interwoven nitinol stent is a promising treatment for failing AVGs with recurrent intragraft stenoses. The 1-year access circuit primary, secondary, and target lesion patency rates were acceptable, with a low reintervention rate. Stent fracture does not occur in areas of needle puncture.