Arteriovenous Access Grafts Research Articles

Treatment with a self-expanding endoprosthesis in patients with stenosis or occlusion at the arteriovenous graft: 6-Month outcomes of a post-marketing surveillance study.

To assess 6-month safety and efficacy of a self-expanding stent graft placement to treat stenotic or thrombosed synthetic arteriovenous access graft at the venous anastomoses. This prospective, multicenter, post-market surveillance study assessed the GORE® VIABAHN® Endoprosthesis (stent graft) in Japanese patients with stenotic or thrombosed vascular access grafts. Key efficacy and safety outcomes were primary patency (PP) and secondary patency (SP) of the target lesion and the vascular access circuit, repeat interventions, technical and clinical success, incidence of adverse and serious adverse events, and device deficiencies through 6 months. The 103 enrolled patients (mean age 71.8 years; 57.3% female) had stent grafts placed in the venous anastomosis of arteriovenous access grafts (on-label). The majority of lesions were stenotic (77.1%) and located in the upper arm (91.4%). Mean lesion length was 42.9 ± 23.6 mm and diameter was 6.7 ± 1.9 mm; 28 patients (27.2%) had elephant trunk placements. Technical and clinical success rates were 100%. At 6 months, Kaplan-Meier estimates of target lesion and circuit PP were 75.1% (95% CI: 65.2, 82.6) and 66.8% (95% CI: 56.4, 75.3), and SP rates were 93.8% (95% CI: 86.7, 97.2) and 93.8% (95% CI: 86.7, 97.2), respectively. Mean cumulative number of reinterventions (0.36; 95% CI: 0.20, 0.51) and incidence of device- or procedure-related adverse events were low (⩽3%). No device deficiencies were reported. The 6-month outcomes of the self-expanding stent graft to treat thrombosed venous anastomoses of synthetic hemodialysis vascular access grafts with stenosis demonstrated safety and effectiveness.

Existing and Evolving Therapies for Arteriovenous Fistula and Graft Dysfunction

A functional vascular access (VA) is of paramount importance to patients on hemodialysis therapy. While arteriovenous fistula (AVF) remains the preferred VA, their long-term patency is unpredictable. A dysfunctional VA contributes to a high morbidity rate, an increased susceptibility to major adverse cardiovascular events, recurrent hospitalization, and a poor quality of life. The recent innovations in devices and technologies have significantly expanded our options to create and prolong VA patency. Endovascular devices such as WavelinQ and Ellipsys are recent additions to creating a VA. The endovascular creation of AVF helps reduce the wait time and potentially avoids or reduces the duration of catheter use. The bioengineered graft and immediate access arteriovenous graft offer reasonable alternatives in a select group of patients. There is growing evidence that covered stents and drug-coated balloons offer options to prolong the VA patency. Finally, the role of stem cell therapy in VA is currently being explored. This article presents a comprehensive review of the conventional and current developments in the management of a dysfunctional VA.

The Association of Satisfaction Level with Vascular Accesses and Adherence to Treatment among Haemodialysis Patients in Malaysia

Introduction: End-stage renal disease (ESRD) requiring hemodialysis has shown an increasing trend in Malaysia. Vascular access (VA) dysfunction is among the primary reasons behind morbidity and mortality among ESRD patients. VA dysfunction exits in all three (3) types of available access: arteriovenous graft (AVG), arteriovenous fistula (AVF), and central venous catheter (CVC). In Malaysia, among the largest causes and the issues of failure in hemodialysis (HD) treatment is the lack of good vascular access (VA). The purpose of this study is to identify the level of satisfaction and the association of HD vascular access with adherence to treatment among hemodialysis patients. Methodology: This quantitative cross-sectional and observational study included 118 ESRD patients among selected Private Hospital in Malaysia. Comparison between access satisfaction and adherence across access type. One way ANOVA was conducted to see the mean difference between the three types of vascular access. Finding: The results shows, AVF was used by 52.3%, AVG by 27.9%, and CVC by 18.6% from overall patients. A one Way ANOVA shows a significant difference in satisfaction between the three types of vascular access with lowest mean score (showing highest satisfaction) in patients with AVG, and then followed by AVF, and CVC (27.84 vs 31.66 vs 44.29; P =.001). Conclusion: The findings of the study have shown that, patients with AVG access type experienced high satisfaction and high adherence to treatment among hemodialysis patients. Compared to the AVF, AVG have greatest advantages such as AVG suitable for patent’s with small or weak vein, especially among the diabetic patients.

The Impact of Seasonality on Prosthetic Arteriovenous Vascular Access Graft Thrombosis

Highlights Abstract Introduction: Arteriovenous prosthetic grafts are susceptible to recurrent thrombotic occlusions mainly due to venous outflow disease secondary to neointimal hyperplasia. Maintenance of vascular access for dialysis is a perpetual challenge for both patients and health care systems. In regions with hotter climates, there is a clinical impression that episodes of prosthetic arteriovenous vascular access graft thrombosis are more frequent during hot dry summers secondary to dehydration and increased blood viscosity. Seasonality of thrombotic events has been observed in multiple vascular beds. However, a seasonal pattern or any association of arteriovenous graft thrombosis with temperature and relative humidity levels has never been fully demonstrated. Methods: Data were collected prospectively from January 2014 until December 2020 but analyzed retrospectively. In this 7-year timeframe, 289 episodes of arteriovenous graft thrombosis were identified from 142 grafts fashioned. Results: No monthly variation (P = 0.35) or seasonal variation (P = 0.91) was identified. No statistically significant correlation between episodes of thrombosis and mean monthly temperature and mean relative humidity was noted. Conclusion: No evidence was identified to support this theory. However, multiple issues with assessments of events must be conceded. Graft thrombosis is multifactorial in nature, and venous outflow disease contributes toward a significant number of these events. Within our local cohort, a low primary patency rate was identified, which further contributes to graft interventions. Relatively small numbers were recruited, and therefore, potential correlations could have been missed.

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.

First Clinical Results of the Merit WRAPSODY\u2122 Cell-Impermeable Endoprosthesis for Treatment of Access Circuit Stenosis in Haemodialysis Patients

PurposeThis prospective, observational first in human study evaluated the safety and effectiveness of WRAPSODYTM Cell-impermeable Endoprosthesis (Merit Medical Systems, Inc.) in the treatment of arteriovenous fistula and arteriovenous graft access circuit stenosis.Materials and MethodsInvestigators conducted a prospective analysis of 46 patients with access circuit stenosis from three centres. Treatment sites included the peripheral outflow veins (e.g. cephalic arch, basilic vein swing point; 16 fistula and 10 graft patients); the graft-vein anastomosis (9 patients); and the central veins (up to, but not including the SVC; 11 patients). Primary outcome measures included 30-day freedom from access circuit-related safety events and 30-day target lesion primary patency. Secondary outcome measures included procedural success; device- and procedure-related adverse events; target lesion primary patency; access circuit primary patency; and secondary patency. In-person follow-up was scheduled at 1, 3, 6, and 12 months. An independent data monitoring/clinical event committee adjudicated all reinterventions and device/procedure-relatedness for adverse events.ResultsAll initial procedures were successful. All but one patient was free from safety events through the first 30 days (97.8% (45/46)). This event was not device-related. Over the remainder of the study, one adverse event was adjudicated as possibly device-related. Six- and 12-month target lesion primary patency rates were 97.7% (42/43) and 84.6.% (33/39), respectively. Six- and 12-month access circuit primary patency rates were 84.4% (38/45) and 65.9% (29/44), respectively.ConclusionResults suggest that the study device is safe and effective for treatment of stenoses in the peripheral and central veins of arteriovenous access circuits.Level of EvidenceLevel 2b, cohort study.

Application and implications of a standardised reporting system for arteriovenous access graft infection.

The perception that arteriovenous graft infection (AVGi) is frequent and severe is not based on contemporary data from large units using modern AVG. Furthermore, older reports compounded misperceptions by using non-standardised reporting that prevents easy comparison against the alternative modalities. The aim of this article is to use a recently published reporting scheme to analyse the frequency, management and outcome of AVGi in a large series of sequential early-cannulation AVG with long-term follow-up. A single-center series analysis was performed of 277 early-cannulation AVG with minimum 1-year follow-up (total 120,082 days). Infections relating to the AVG were classified, root-cause analysed and the outcomes presented. Sixteen percent of all AVG implanted (51 episodes) developed infection related to the AVG. Primary AVGi (related to the insertion procedure or within 28 days) occurred in 9 (3%); secondary AVGi (related to AVG in use) occurred 33 times (rate 0.27/1000 haemodialysis days), at a mean of 382 days, and tertiary AVGi (in AVG no longer in use) occurred nine times. Only 1/3 of all AVGi led to bacteraemia, and ½ did not lead to loss of functional access. AVG infection is not common, caused a systemic infection in only one-third, did not lead to metastatic infection, and importantly, was treatable without loss of access in one-half of all cases. Using an objective system that discriminates between aetiology and outcome allows a more complete objective understanding of relative infection risks and outcomes for AVG that can inform discussions with patients requiring vascular access for haemodialysis.

Epidemiology of bloodstream infections in a Scottish haemodialysis population with focus on vascular access method

Infection is the second highest cause of mortality in end-stage renal disease, with a significant proportion relating to haemodialysis (HD) vascular access-related infection (VARI). To report the rate and antimicrobial resistance (AMR) of all-source bloodstream infections (BSIs) by vascular access type in a Scottish HD cohort. Retrospective analysis was undertaken of data on adult patients attending seven HD units during 2017. Total HD days for each vascular access type were calculated. BSIs were analysed with rates expressed per 1000 HD days. AMR was verified using health board microbiology databases. Excluding contaminant organisms, there was an overall BSI rate of 0.57 per 1000 HD days. The highest all-source and vascular access-related infection (VARI) BSI rates per 1000 HD days were in the non-tunnelled central venous catheter (CVC) group (3.11 and 2.07 respectively), followed by tunnelled CVC (1.10 and 0.67), arteriovenous graft (0.51 and 0.31), and finally arteriovenous fistula (0.29 and 0.02). The non-VARI BSI rates were lowest in the arteriovenous graft group. Staphylococci comprised the majority of events, with Staphylococcus aureus implicated in 29%. Gram-negative BSIs were prevalent, particularly in CVC groups, and associated with higher mortality. Multidrug-resistant (MDR) S.aureus and carbapenem resistance were relatively low. MDR Gram-negatives were high compared with the Scottish population. Arteriovenous fistula access is confirmed as having lowest all-source and VARI BSI rates, and arteriovenous graft access the lowest non-VARI BSI rates. Staphylococci remain the prevailing genus; however, the contributions of Gram-negative BSIs, the higher mortality, and proportion of MDR organisms in this group are notable.

Balloon-assisted maturation of autogenous arteriovenous fistulae: A randomized controlled prospective study.

Current guidelines recommend referral of patient with renal failure for access creation 6 months before planned dialysis. There is a growing cohort of patients that require long-term hemodialysis without adequate preparation. Temporary dialysis catheters and rapid access arteriovenous grafts (AVG) are far from being an ideal solution in this scenario. In an effort to expedite maturation of autogenous arteriovenous fistulae (AVF), balloon-assisted maturation (BAM) was advised by some authors. This technique still lacks the support of high-level evidence studies. We investigated the ability of intra-operative BAM to induce early functional maturation of AVFs. This is a prospective randomized controlled study conducted in a tertiary referral center, with a catchment area of more than 15 million population. Cases were divided into two groups; Group (A), where BAM technique was performed, while in the control group (B), the standard technique was used (NO BAM) for creation of AVFs. Between June 2017 and May 2019, 300 cases were recruited from a total of 648 primary AVF creation instances. Patients' age ranged from 19 to 89 (mean 51.17 ±SD 15.5) years. Group A (BAM) included 52.3% (n = 157) AVFs, while Group B included 47.7% (n = 143) AVFs. The average maturation time was 3.7 weeks (SD ± 1.3, 95% CI 3.55-3.95) and 5.91 weeks (SD ± 2.2, 95% CI 5.55-6.26) for both groups, respectively (p = 0.0001). 78.3% of the AVFs that underwent BAM showed early maturation within 2-4 weeks vs 32.2% only in the NO BAM group (p = 0.002). Successful functional maturation was higher among cases of the BAM group (93%), compared to the NO BAM group (77%) (p = 0.001). Complication rates were 9.6% and 4.9% in the two groups, respectively (p = 0.042). BAM can play a pivotal role in helping the dialysis society meet the goals of the Fistula First Initiative, keeping in mind that this comes with an increased risk of complications. BAM should be considered only when unplanned early access to long-term dialysis is required.

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.

P1313CHANGES IN VASCULAR ACCESS AND HEALTH-RELATED QUALITY OF LIFE

Abstract Background and Aims The patient’s reported perception of their health-related quality of life (HRQOL) are important patient-centered metrics that associate with outcomes in hemodialysis (HD) populations. Patients using an arteriovenous (AV) access (fistula or graft) tend to report better HRQOL compared with those dialyzing via a catheter (Wasse et al. 2007; Moura et al. 2014). However, these differences might be due to distinct characteristics of patients who have an AV access placed, or not. For example, catheter-dependent patients are typically older and have more comorbidities than those with an AV access. We considered a different way to evaluate the impact of vascular access on HRQOL in HD patients by assessing whether a change from a catheter to an AV access, and vice versa, associates with changes in HRQOL. Method We used data from adult in-center HD patients (age ≥18 years) treated at a large dialysis organization in the United States from 2016-2017. Patients who had one vascular access conversion and used the corresponding access for at least 12 months before and after the conversion were included in the analysis. HRQOL was assessed by Kidney Disease Quality of Life (KDQOL-36) surveys (0-100 scale) performed over the 12 months preceding and following the change. We computed the mean score for each of the five KDQOL domains in each time period and compared the score differences between pre- and post-access change using Student’s t-tests for each conversion type. Results A total of 1088 HD patients (mean age 59.2 years, 52.6% male, and 59.3% white race) switched from a catheter to an AV access and 3427 patients (mean age 61.8 years, 47.8% male, and 50.7% white race) switched from an AV access to a catheter over the analysis period. After conversion from a catheter to an AV access, patients reported significantly higher physical component summary (+0.5, p<0.05), mental component summary (+0.8, p<0.001), symptoms and problems of kidney disease (+0.7, p<0.05), and effects of kidney disease (+1.2, p<0.05) scores (Figure 1). No significant difference was observed for four out of the five domains following the change from an AV access to a catheter, except for physical component summary, where the score dropped by 1.2 points (p<0.01) (Figure 2). Conclusion Our results suggest switching from a catheter to an AV access may associate with patients perceiving an improved physical and mental HRQOL. In contrast, changing from an AV access to a catheter might associate with a diminished perception of physical HRQOL. Albeit distinctions in HRQOL are statistically significant, absolute differences were below two points and the clinical meaning needs to be assessed in further adjusted analyses considering the underlying reasons for vascular access conversions. Nonetheless, these findings may be of importance to provide more patient focused care.

Cost-effectiveness analysis of immediate access arteriovenous grafts versus standard grafts for hemodialysis

ObjectiveImmediate-access arteriovenous grafts (IAAVGs), or early cannulation arteriovenous grafts (AVGs), are more expensive than standard grafts (sAVGs) but can be used immediately after placement, reducing the need for a tunneled dialysis catheter (TDC). We hypothesized that a decrease in TDC-related complications would make IAAVGs a cost-effective alternative to sAVGs. MethodsWe constructed a Markov state-transition model in which patients initially received either an IAAVG or an sAVG and a TDC until graft usability; patients were followed through multiple subsequent access procedures for a 60-month time horizon. The model simulated mortality and typical graft- and TDC-related complications, with parameter estimates including probabilities, costs, and utilities derived from previous literature. A key parameter was median time to TDC removal after graft placement, which was studied under both real-world (7 days for IAAVG and 70 days for sAVG) and ideal (no TDC placed with IAAVG and 1 month for sAVG) conditions. Costs were based on current Medicare reimbursement rates and reflect a payer perspective. Both microsimulation (10,000 trials) and probabilistic sensitivity analysis (10,000 samples) were performed. The willingness-to-pay threshold was set at $100,000 per quality-adjusted life-year (QALY). ResultsIAAVG placement is a dominant strategy under both real-world ($1201.16 less expensive and 0.03 QALY more effective) and ideal ($1457.97 less expensive and 0.03 QALY more effective) conditions. Under real-world parameters, the result was most sensitive to the time to TDC removal; IAAVGs are cost-effective if a TDC is maintained for ≥23 days after sAVG placement. The mean catheter time was lower with IAAVG (3.9 vs 8.7 months; P < .0001), as was the mean number of access-related infections (0.55 vs 0.74; P < .0001). Median survival in the model was 29 months. Overall mortality was similar between groups (76.3% vs 76.7% at 5 years; P = .33), but access-related mortality trended toward improvement with IAAVG (6.1% vs 6.8% at 5 years; P = .052). ConclusionsThe Markov decision analysis model supported our hypothesis that IAAVGs come with added initial cost but are ultimately cost-saving and more effective. This apparent benefit is due to our prediction that a decreased number of catheter days per patient would lead to a decreased number of access-related infections.

Perioperative and long-term outcomes after percutaneous thrombectomy of arteriovenous dialysis access grafts

ObjectiveMaintenance of functional arteriovenous grafts (AVGs) for dialysis is difficult secondary to low primary patency, need for reinterventions, and limited alternative dialysis access options. We assessed our experience with percutaneous thrombectomy for treatment of occluded AVGs. MethodsWe performed a retrospective analysis of all percutaneous thrombectomies for AVGs from 2015 to 2017. These were generally performed using mechanical thrombectomy and occasional chemical tissue plasminogen activator thrombolysis, over-the-wire balloon embolectomy for inflow, and adjunctive inflow and outflow interventions as necessary. Perioperative outcomes, long-term patency, reinterventions, and need for new permanent access placement were analyzed. ResultsThere were 218 percutaneous thrombectomies performed on 86 AVGs in 77 patients. Approximately half (53.2%) of the patients were male and 68.8% were black. Mean age was 61.1 ± 13.0 years. At the time of thrombectomy, 73.8% underwent venous outflow interventions and 4.5% underwent arterial inflow interventions. Within 30 days, 24.8% of declotted grafts underwent repeated percutaneous thrombectomy, 14.3% required tunneled dialysis catheter placement, 4% developed minor access site or graft infections, and one patient underwent surgical arterial thrombectomy for arm ischemia. There were no venous thromboembolic, cardiopulmonary, or cerebrovascular complications or clinically significant pulmonary embolism. At 1 year and 3 years after percutaneous thrombectomy, freedom from repeated thrombosis was 37% and 18%, respectively, and freedom from new dialysis access placement was 66% and 51%, respectively. Overall patient survival was 82% at 3 years. ConclusionsPercutaneous thrombectomy of AVGs is safe and is associated with acceptable patency rates. This minimally invasive method extends AVG use for these high-risk patients with limited dialysis access options.

Immediate Access Arteriovenous Grafts Decrease Catheter Days and Complications

Introduction - Immediate-access arteriovenous grafts (IAAVG) can be used as peripheral access or in combination with outflow through the Hemodialysis Reliable Outflow (HeRO) graft. This study compares IAAVG to standard arteriovenous grafts (SAVG) as well as describing IAAVG use with HeRO outflow. Methods - All patients who underwent placement of AV graft from 1/2014 - 4/2016 at two large tertiary referral centers were retrospectively identified in the electronic medical record and through the Vascular Quality initiative (VQI). Patients were divided into three groups based on the type of graft implanted (SAVG and IAAVG) and a third group of HeRO/IAAVG. Patient comorbidities, graft configuration, operative characteristics and subsequent follow-up were collected and analyzed with respect to primary patency, primary assisted patency, and secondary patency. Additional outcomes included graft-related complications, time to first canulation, time to tunneled catheter removal, catheter-related complications and overall survival. Patency was defined per Society for Vascular Surgery recommended reporting standards and was determined from the time of the index procedure. Chi-square, Kaplan-Meier and Cox regression analysis were used with the p-value set as significant at <0.05 Results - 254 grafts were identified; 148 SAVG, 62 IAAVG, 44 combined IAAVG-HeRO. Patient characteristics were similar between groups, except for more pre-operative central venous occlusions in the IAAVG vs SAVG (16.3% vs 6.8%, p<0.04) and these vs IAAVG/HeRO (100%, P<.001) . Of the IAAVG group, 50 were Acuseal (Gore) and 12 were Flixene (Atrium). IAAVG/HeR0 patients all used Acuseal. Standard AVG were all ePTFE (Gore Medical). Overall primary, primary assisted, and secondary patency at 6 months were 35.9%, 43.6%, and 51.3% respectively for IAAVG/HeRO. Primary patency at 1 year (SAVG: 39.4%, IAAVG: 56.7%, p=0.4), and secondary patency (SAVG: 50.7%, IAAVG: 52.1%, p=0.73) showed no significant differences. Similarly, there were no significant differences in primary (SAVG: 29.0%, IAAVG: 43.7%, p=0.4) or secondary patency (SAVG: 42.3%, IAAVG: 46.3%, p=0.73) at 18 months. Regression analysis did not show any association to the type of graft; however, IAAVG patients required fewer additional procedures to maintain patency (mean number of procedures 0.99 SAVG vs. 0.61 IAAVG, p=0.025). There was no difference in steal syndrome (SAVG: 6.8%, IAAVG: 8.1%, p=0.74).) or graft infection (19.0% SAVG vs. 12.0% IAAVG, p=0.276). 75% of all grafts were successfully canulated, with shorter median time to first canulation in the IAAVG group (6 days IQR 1-19) compared to the SAVG group (31 days, IQR 26-47) (p<0.01). For IAAVG/HeRO) patients, 95% of grafts were successfully canulated with mean time to canulation of 13.0±51.6 days. 53% of IAAVG/HeRO patients left the OR with this graft as their only access. This group had 100% canulation success at < 24 hours. 65.75% of all pre-existing catheters were removed, with a shorter median time until catheter removal in the IAAVG cohort at 34 days (IQR 22-50) versus 49 days (IQR 39-67) in the SAVG group (p<0.01). Catheter-related complications occurred less frequently in the IAAVG group (16.4% vs. 2.9%, p<0.045). Conclusion - IAAVGs allow earlier canulation and tunneled catheter removal, thereby significantly decreasing catheter-related complications. Patency and infection rates were similar between SAVG and IAAVG, but with fewer secondary procedures performed in IAAVG.

Early Cannulation ePTFE Arteriovenous Access Grafts are Associated with a Low Incidence of Pseudoaneurysm Formation

Pseudoaneurysm formation is common in standard thin-walled polytetrafluoroethylene (sPTFE) grafts, occurring in up to 10% of grafts, and is reported as the most common cause of graft loss for grafts more than 2years old. The Gore® Acuseal™ graft is an early cannulation graft, needled before incorporation, and thus may be especially prone to pseudoaneurysm formation. In addition, as this is a relatively new product, there are limited data on long-term outcomes such as pseudoaneurysm. We report one center's experience of the incidence and etiological factors associated with pseudoaneurysm formation over 5years and 265 grafts. A total of 265 Acuseal grafts were placed in the last 5years. All patients had prospective data entered into an electronic searchable patient record. Surveillance was performed with 3 monthly imaging (digital subtraction angiography or ultrasound), clinical examination, and hemodynamic performance. Data examined included the incidence, causative factors, and outcomes of pseudoaneurysm. Eleven grafts (4.15%) developed a pseudoaneurysm, with 2 patients developing significant hemorrhage. The median time to development of a pseudoaneurysm was 25months interquartile range (IQR, 20-28months). Several common etiological factors were identified. All but one patient had overuse of needling sites (n=10; 90.9%). Other factors associated with pseudoaneurysm formation were inadequate surveillance (n=9; 81.8%), venous outflow stenosis (n=9; 81.8%), and anticoagulation/dual antiplatelet therapy (n=7; 63.6%). Management included observation and needle rotation (n=5; 45.5%), stent grafting (n=3; 27.3%), or excision (n=1; 9.1%) of the pseudoaneurysm. Surgical or endovascular augmentation of the venous outflow was required in 9 patients (81.8%). Graft ligation and explantation were required in 5 patients (45.5%) with graft preservation achieved in 6/11 patients (54.5%). Pseudoaneurysm formation occurs less frequently in Acuseal grafts compared with historical data for standard PTFE grafts. Pseudoaneurysm formation did not occur in any graft within the first 13months after implantation, suggesting early cannulation before incorporation is not by itself a risk factor for pseudoaneurysm development. Poor needling, venous stenosis, inadequate surveillance, and anticoagulation/dual antiplatelet therapy are remediable factors, and graft preservation is possible. Acuseal is a robust graft with lower rates of pseudoaneurysm formation on long-term follow-up than standard PTFE grafts.

Current Experience and Midterm Follow-up of Immediate-Access Arteriovenous Grafts

No independent reviews, with midterm follow-up, of current experience with immediate-access arteriovenous grafts (IAAVGs) exist. The goal of this project was to assess the real-world performance of 2 different IAAVGs over a 2-year period at a large tertiary referral center. Between January 2014 and April 2016, all consecutive patients who underwent placement of Acuseal (Gore) or Flixine (Maquet) IAAVGs were identified for retrospective analysis from the electronic medical record and Vascular Quality Initiative database. Primary, primary-assisted and secondary patency rates, time to first cannulation, time to tunneled catheter removal, and overall survival were recorded. Forty-three patients were identified to have undergone placement of IAAVG, 31 Acuseal (72%), and 12 Flixine (28%). Of the Acuseal cohort, 7 were implanted with outflow through a HeRO catheter system (Merit Medical). Mean follow-up time was 8.4months. Overall survival was 57.4% at 18months. Overall primary, primary assisted, and secondary patency at 18months were 33.36%, 34.31%, and 51.03%, respectively. Eighty three percent of grafts were successfully cannulated, and 78% of preexisting catheters were removed. Mean time to successful graft cannulation and catheter removal were 14.85 and 32.26days, respectively. Real-world experience with novel arteriovenous access grafts is consistent with results from industry-sponsored studies. Early cannulation of immediate-access grafts can be successfully performed in a wide variety of patients. However, prolonged catheter dwell times persist despite increased rates of successful early-graft cannulation. Further study of methods for promoting catheter removal in this patient population is warranted.

Long-term results of thigh arteriovenous dialysis grafts.

A proportion of hemodialysis patients exhaust all options for arteriovenous access in upper extremities. Arteriovenous thigh grafts are a potential vascular access option in such patients. We performed a retrospective study of all thigh arteriovenous access grafts placed between 1995 and 2015. The clinical, demographic patient information and patency of each thigh graft was determined from the time of surgical creation placement until abandonment, transfer to other modality, or center or end of study, and the reason for access failure documented. In total, 44 patients received 49 thigh arteriovenous accesses. The average age was 60 years (13-79 years); Half (53%) of the patients (n = 24) were female and 61% of the patients (n = 30) of arteriovenous accesses were left-sided. The cumulative proportion surviving (primary patency rates) at 12, 24, and 28 months were 43% (standard error = 9%), 33% (standard error = 9%), and 13% (standard error = 9%), respectively. The cumulative proportion of surviving grafts at 12, 24, and 48 months were 61% (standard error = 8%), 58% (standard error = 9%), and 31% (standard error = 13%), respectively. In total, 37 revisions were performed in 22 patients to maintain patency or eradicate infection. Infection occurred in 20 patients (39%) of thigh grafts requiring 16 patients (80% of those affected) to be removed; 14 patients had grafts (33.3%) that served as the lone hemodialysis arteriovenous access during the patients' lifetime on dialysis. Arteriovenous thigh graft access is used infrequently, but they have an acceptable patency. Some accesses require revisions and they have a high infection rate. Despite this, an acceptable proportion of leg grafts provide durable access for the dialysis lifetime of the patient.

Management of Complications of Arteriovenous Grafts in Patients with Chronic Renal Failure

Background: With increasing number of patients sustained on chronic Haemodialysis, access related surgery forms a significant proportion of vascular surgical practice today. A cursory review of patients with Arteriovenous graft access reveals a considerable variety in short and long-term complications that could happen and in the management of those complications. Aim: The aim of this work is to assess the outcomes of different modalities of management of complications of Arteriovenous grafts in chronic renal failure patient on regular hemodialysis from arteriovenous graft. Patients and Methods: Thirty chronic renal failure patients with complicated Arterio-venous grafts performed before for regular hemodialysis were enrolled into this study. The patients were recruited from the Vascular Surgery outpatient clinic of El-Hussein University Hospital. Patients were followed up at intervals of: immediately after fistula creation, first day after creation, 1 month, 3 months, 6 months and 9 months after creation for detecting any complications. Follow up of all patients was based on clinical examination and also by duplex ultrasound and CT venography if needed. Results: Arteriovenous graft complications incidence were higher in male than females, those results were explained by male cases being associated with more co-morbidities and smoking. Venous outflow stenosis and venous hypertension were the most encountered complication, while surgical management in form of ligation and excision was the commonest management modality used. We also noticed a correlation between the duration from creation of AV synthetic graft and interval between primary and secondary intervention. The older the AV graft the longer was the interval between primary and secondary intervention. This can be correlated to years of education those group of patients had, as those patients tended to pay more attention to early manifestations and used better dialysis centers. Conclusion: Surgical management in form of graft ligation and excision or surgical revision seems to be the simplest yet most effective management modality facing the majority of the complications not neglecting the role of endovascular intervention in venous hypertension.

Management of Complications of Arteriovenous Grafts in Patients with Chronic Renal Failure

Background: With increasing number of patients sustained on chronic Haemodialysis, access related surgery forms a significant proportion of vascular surgical practice today. A cursory review of patients with Arteriovenous graft access reveals a considerable variety in short and long-term complications that could happen and in the management of those complications. Aim: The aim of this work is to assess the outcomes of different modalities of management of complications of Arteriovenous grafts in chronic renal failure patient on regular hemodialysis from arteriovenous graft. Patients and Methods: Thirty chronic renal failure patients with complicated Arterio-venous grafts performed before for regular hemodialysis were enrolled into this study. The patients were recruited from the Vascular Surgery outpatient clinic of El-Hussein University Hospital. Patients were followed up at intervals of: immediately after fistula creation, first day after creation, 1 month, 3 months, 6 months and 9 months after creation for detecting any complications. Follow up of all patients was based on clinical examination and also by duplex ultrasound and CT venography if needed. Results: Arteriovenous graft complications incidence were higher in male than females, those results were explained by male cases being associated with more co-morbidities and smoking. Venous outflow stenosis and venous hypertension were the most encountered complication, while surgical management in form of ligation and excision was the commonest management modality used. We also noticed a correlation between the duration from creation of AV synthetic graft and interval between primary and secondary intervention. The older the AV graft the longer was the interval between primary and secondary intervention. This can be correlated to years of education those group of patients had, as those patients tended to pay more attention to early manifestations and used better dialysis centers. Conclusion: Surgical management in form of graft ligation and excision or surgical revision seems to be the simplest yet most effective management modality facing the majority of the complications not neglecting the role of endovascular intervention in venous hypertension.

Engineered Blood Vessels

The field of tissue engineering has has made significant progress in the past 20 years. Of the many tissues and organs in development, the area of vascular tissue engineering is now one of the most mature. In that regard, we have developed a novel tissue engineered vascular graft (human acellular vessel [HAV]) that addresses many of the limitations of native vein harvest and the performance of both synthetic ePTFE and autologous vein grafts. The HAV is manufactured in a laboratory by culturing human vascular cells within a biodegradable scaffold that forms a mechanically robust tissue engineered blood vessel. The cells are then completely removed (decellularization), leaving behind a non-immunogenic human collagen-based vascular tissue that can be stored on the shelf for months at a time and ready for immediate implantation into any patient. The HAV is currently being evaluated in Phase II and Phase III clinical trials in the U.S., E.U. and Israel as an arteriovenous vascular access graft for hemodialysis in patients with end-stage renal failure and as an arterial substitute for patients in need of vascular bypass for peripheral arterial disease or vascular trauma. Following clinical implantation, we have observed repopulation and remodeling of the manufactured vessel with the hosts' own cells. We hypothesize that the biological composition of the HAV, compared to synthetic vascular grafts, promotes its physiological integration into host tissue including support of normal host cell infiltration and function. Host cells that identify histologically similar to vascular smooth muscle cells appear to repopulate the middle of the vessel and recipient cells characterized as endothelial cells appear to cover the luminal surface of the implanted vessel. Clinical observations of the Phase II trials have demonstrated excellent vessel durability and a freedom from both early and delayed infection. Based on the success of the Phase II studies, a Global Phase III study is underway for patients in need of dialysis access shunts and vascular programs for vascular (arterial) bypass and trauma are expanding. DisclosuresLawson:InnaVasc: Patents & Royalties; Humacyte, Inc.: Employment.