Access Circuit Primary Patency Research Articles

Safety and Performance of a Cell-Impermeable Endoprosthesis for Hemodialysis Vascular Access Outflow Stenosis: A Brazilian Multicenter Retrospective Study.

To evaluate the safety and performance of Wrapsody™, a cell-impermeable endoprosthesis (CIE), for treating hemodialysis vascular access outflow stenosis. Investigators retrospectively analyzed 113 hemodialysis patients treated with a CIE (11/2021-12/2022) across four centers in Brazil. Denovo or restenotic lesions were treated. The primary efficacy outcome measure was target lesion primary patency (TLPP) at 1, 3, 6, and 12months; the primary safety outcome measure was the absence of serious local or systemic adverse events within the first 30days post-procedure. Secondary outcome measures included technical and procedural success, access circuit primary patency (ACPP), and secondary patency at 1, 3, 6, and 12months post-procedure. Thirty-nine patients (34.5%) had thrombosed access at the initial presentation, and 38 patients (33.6%) presented with recurrent stenosis. TLPP rates at 1, 3, 6, and 12months were 100%, 96.4%, 86.4%, and 69.7%, respectively. ACPP rates were 100% at 1month, 89.2% at 3months, 70.9% at 6months, and 56.0% at 12months. The target lesion secondary patency rates at 1, 3, 6, and 12months were 100%, 97.3%, 93.6%, and 91.7%, respectively. In the adjusted multivariate Cox regression analysis, male sex and endoprosthesis with diameters of 10, 12, 14, and 16mm were associated with improved primary patency rates. No localized or systemic serious adverse event was observed through the first 30days post-procedure. The CIE evaluated in this study is safe and effective for treating peripheral and central outflow stenoses in hemodialysis vascular access. Level 2b, cohort study.

Clinical outcomes and predictive factors of stent grafts treatment for symptomatic central venous obstruction in end stage kidney disease patients with arteriovenous access

To assess the efficacy of stent grafts (SGs) in managing central venous obstruction disease (CVOD) in hemodialysis (HD) patients with arteriovenous (AV) access, and to identify predictive factors influencing the SG treatment outcomes. HD subjects with CVOD who underwent SGs placement at our center between August 2018 and June 2022 were enrolled. Survival curve analysis using the Kaplan–Meier method and log-rank test was performed. Cox proportional hazards regression analysis was employed to identify predictive factors associated with outcomes. A total of 59 SG implantation procedures for CVOD were analyzed, comprising 30 cases of stenosis and 29 cases of occlusion. The access circuit primary patency (ACPP) at 6, 12, and 24 months post-SG placement were 80.9%, 53.8%, and 31.4%, respectively, while, the target lesion primary patency (TLPP) were 91.3%, 67.6%, and 44.5%, respectively. Subgroup analysis revealed higher TLPP in the stenosis group compared to the occlusion group, although the difference was not statistically significant (P = 0.165). The TLPP was significantly improved by SG placement in those who had antecedent balloon dilations (P < 0.001). Cox proportional hazards regression identified target lesion length ≥ 30 mm and procedure defects as independent predictors of lower TLPP after SG treatment for CVOD in HD patients. SG placement demonstrates safety and efficacy in managing CVOD among HD patients, leading to improved TLPP of endovascular therapy (EVT) for CVOD. Notably, long target lesions (≥ 30 mm) and procedure defects emerged as predictive factors influencing TLPP.

Comparison of Outcomes of Drug-Coated Balloons versus Plain Balloons in Secondary Interventions on Percutaneous Arteriovenous Fistulae

PurposeTo compare patency and reintervention outcomes after either plain old balloon angioplasty (POBA) or drug-coated balloon angioplasty (DCBA) for venous stenoses after percutaneous arteriovenous fistula (pAVF) creation. Materials and MethodsOne-hundred ninety-five pAVFs were successfully created during the study period, 141 using Ellipsys and 54 using Wavelinq. After pAVF creation, 95 patients (48.7%) required secondary percutaneous transluminal angioplasty (PTA) with either POBA (n = 55, 58%) or DCBA (n = 40, 42.1%). The most common site for PTA was the juxta-anastomotic segment (75.5%; 74/98). Univariate and multivariate Cox regression analyses were used to compare target lesion primary patency, access circuit primary patency, secondary patency, and reintervention rates in the POBA and DCBA cohorts. ResultsThirty-four of 55 (62%) patients in the POBA cohort and 14 of 40 (35%) patients in the DCBA cohort required reinterventions for pAVF restenosis. Mean number of follow-up days among patients treated with POBA was 1,030.4 (SD ± 342.9) and among those treated with DCBA was 744.4 (SD ± 403.5). The use of POBA compared with DCBA was not associated with target lesion and access circuit primary patency loss in multivariate analysis (hazard ratio [HR], 1.81; 95% CI, 0.93–3.51; P = .080; and HR, 1.77; 95% CI, 0.73–4.28; P = .210, respectively). However, time from fistula creation to the first PTA (days) was statistically significantly associated with both outcomes (HR, 0.997; 95% CI, 0.994–0.999; P = .009; and HR, 0.997; 95% CI, 0.992–0.999; P = .021, respectively). There were no major adverse events. ConclusionsIn this retrospective single-center analysis of pAVFs, considerably more patients who underwent PTA with POBA after pAVF creation required reinterventions compared with PTA using DCBA, although the follow-up time of POBA was longer. In multivariate analysis, no differences were noted in the hazard of patency loss between POBA and DCBA.

Safety and efficacy of a new covered stent in hemodialysis vascular access outflow stenosis: A Brazilian multicenter retrospective study.

Vascular stenosis commonly leads to dysfunction in hemodialysis vascular access. Although percutaneous transluminal angioplasty is an established treatment, stent utilization has increased in the last decade as an alternative solution to extend the access function. This study evaluated the safety and initial results of a new impermeable covered stent for treating vascular access outflow stenosis. Investigators retrospectively analyzed 114 hemodialysis patients treated with polytetrafluorethylene-covered stents from September 2018 to September 2022 across four centers. Lesions treated were de novo or restenotic and located in the venous graft anastomosis, outflow segment, cephalic arch, and basilic swing point. Patients were followed by in-person physical examination at 1, 3, and 6 months, and Duplex ultrasound was performed to evaluate the vascular access circuit and in-stent restenosis. The primary efficacy endpoint was target lesion primary patency at 1, 3, and 6 months. Secondary endpoints included access circuit primary patency and secondary patency at 1, 3, and 6 months. The primary safety endpoint was freedom from local or systemic serious adverse events through 30 days post-procedure. Forty-four patients had thrombosed access at the initial presentation, and 41 patients presented with recurrent stenosis. The target lesion primary patency rates at 1, 3, and 6 months were 100%, 89.4%, and 74%, respectively. The access circuit primary patency rates were 100% at 1 month, 85% at 3 months, and 62.7% at 6 months. The secondary patency rates at 1, 3, and 6 months were 100%, 96.4%, and 94.6%, respectively. In the adjusted multivariate Cox regression analysis, only recurrent lesions and female gender were associated with reduced primary patency rates. No serious adverse event was observed through the first 30 days post-procedure. In this retrospective analysis, a new covered stent was shown to be safe and effective for treating peripheral outflow stenosis in vascular access.

Angioplasty for dysfunctional arteriovenous fistulas: A meta-analysis of recent randomized controlled trials compared paclitaxel-coated balloon versus conventional balloon angioplasty.

Stenosis in arteriovenous fistulas (AVF) due to neointimal hyperplasia is one of the most common causes of hemodialysis vascular access dysfunction. Treating patients with dysfunctional AVF with drug-coated balloon (DCB) angioplasty may potentially improve outcomes. This systematic review aimed to compare the effectiveness and safety of DCB angioplasty versus conventional balloon angioplasty by pooling evidence from the most recent randomized controlled trials. We conducted a comprehensive literature search in the Web of Science, Embase, and Cochrane central databases. Two independent researchers screened the article, extracted interest, and evaluated included studies for risk of bias. Pooled estimation was conducted in terms of 6-month target-lesion primary patency (TLPP) and target-lesion reintervention (TLR), as well as other outcomes. Results were expressed with odds ratio (OR) and 95% confidence interval (CI). A total of five RCTs were identified and included in the meta-analyses, with 1107 participants. DCB has a trend of a higher rate of TLPP (OR 1.79, 95% CI 0.66-4.90, p = 0.181) and a significantly lower rate of TLR (0.52, 95% CI 0.29-0.92, p = 0.034), as compared to conventional balloon angioplasty. No difference in the 6-month access circuit primary patency and reinvention was observed between the two groups. DCB may be an alternative treatment of dysfunctional AVF given a trend of a higher rate of TLPP and a significantly lower rate of TLR than conventional balloon angioplasty within 6 months after the indexed procedure. Moreover, DCB was non-inferior to conventional balloon angioplasty in terms of safety. Considering variations in the DCB technique, further studies are warranted for a standardized process.

IN.PACT AV Access Randomized Trial of Drug-Coated Balloons for Dysfunctional Arteriovenous Fistulae: Clinical Outcomes through 36 Months

PurposeTo present the 36-month outcomes of the prospective randomized IN.PACT AV Access study of participants with obstructive de novo or restenotic native upper extremity arteriovenous dialysis fistula lesions treated with drug-coated balloon (DCBs) or standard percutaneous transluminal angioplasty (PTA) following successful high-pressure PTA. Materials and MethodsParticipants at 29 international sites were randomized 1:1 to receive an IN.PACT AV DCB (n = 170) or undergo PTA (n = 160). The outcomes through 36 months included target lesion primary patency (TLPP) and access circuit primary patency (ACPP) (composites of clinically driven target lesion or access circuit revascularization and/or access circuit thrombosis), number of reinterventions, and serious adverse events involving the access circuit. ResultsTLPP was 52.1% in the DCB group compared with 36.7% in the PTA group through 24 months and 43.1% in the DCB group compared with 28.6% in the PTA group through 36 months (both log-rank P < .001). ACPP was 39.4% in the DCB group compared with 25.3% in the PTA group through 24 months and 26.4% in the DCB group compared with 16.6% in the PTA group through 36 months (both log-rank P < .001). Cumulative incidence of access circuit thrombosis through 36 months was 8.2% in the DCB group compared with 18.3% in the PTA group (log-rank P = .040). Cumulative incidence of mortality through 36 months was 26.6% in the DCB group compared with 30.8% in the PTA group (log-rank P = .71). ConclusionsThis study demonstrated superior TLPP and ACPP with DCBs compared with PTA, with no difference in mortality through 3 years. Access circuit thrombosis was statistically significantly higher in the PTA group at 3 years.

A Randomised Trial Comparing Drug Coated Balloons and Conventional Balloons for the Treatment of Stent Graft Stenosis in Dialysis Vascular Access

Previous studies on arteriovenous fistulas have demonstrated the potential benefit of drug coated balloons (DCBs) in maintaining the patency of dialysis access. However, stenoses involving stent grafts were excluded from these studies. Therefore, the aim was to evaluate the effectiveness of DCBs in treating stent graft stenosis. This was a prospective, single blinded, randomised controlled study. From March 2017 to April 2021, 40 patients with dysfunctional vascular access owing to stent graft stenosis were randomised to treatment with a DCB or conventional balloon. Clinical follow up was scheduled at one, three, and six months, and angiographic follow up was performed six months after the intervention. The primary outcome was angiographic late luminal loss at six months, and secondary outcomes included target lesion and access circuit primary patency at six months. Thirty-six participants completed follow up angiography. The DCB group had a superior mean late luminal loss at six months compared with the control group (1.82 mm ± 1.83 mm vs. 3.63 mm ± 1.08 mm, respectively, p= .001). All 40 patients completed clinical follow up. The DCB group had a superior six month target lesion primary patency compared with the control group [hazard ratio (HR) 0.23, 95% confidence interval (CI) 0.07 - 0.71; p= .005). Additionally, the DCB group had a numerically higher six month access circuit primary patency rate than the control group, although the difference was not statistically significant (HR 0.54, 95% CI 0.26 - 1.11, p= .095). Conventional balloon angioplasty is not durable in stent graft stenosis treatment. Treatment with DCBs provides less angiographic late luminal loss and potentially superior primary patency of the target lesion than treatment with conventional balloons. [ClinicalTrials ID: NCT03360279.].

Prospective, randomized, multicenter clinical study comparing a self-expanding covered stent to percutaneous transluminal angioplasty for treatment of upper extremity hemodialysis arteriovenous fistula stenosis

Use of a covered stent after percutaneous transluminal angioplasty (PTA) was compared to PTA alone for treatment of upper extremity hemodialysis patients with arteriovenous fistula (AVF) stenoses. Patients with AVF stenosis of 50% or more and evidence of AVF dysfunction underwent treatment with PTA followed by randomization of 142 patients to include a covered stent or 138 patients with PTA alone. Primary outcomes were 30-day safety, powered for noninferiority, and six-month target lesion primary patency (TLPP), powered to test whether TLPP after covered-stent placement was superior to PTA alone. Twelve-month TLPP and six-month access circuit primary patency (ACPP) were also hypothesis tested while additional clinical outcomes were observed through two years. Safety was significantly non-inferior while six- and 12-month TLPP were each superior for the covered stent group compared to PTA alone (six months: 78.7% versus 55.8%; 12 months: 47.9% versus 21.2%, respectively). ACPP was not statistically different between groups at six-months. Observed differences at 24 months favored the covered-stent group: 28.4% better TLPP, fewer target-lesion reinterventions (1.6 ± 1.6 versus 2.8 ± 2.0), and a longer mean time between target-lesion reinterventions (380.4 ± 249.5 versus 217.6 ± 158.4 days). Thus, our multicenter, prospective, randomized study of a covered stent used to treat AVF stenosis demonstrated noninferior safety with better TLPP and fewer target-lesion reinterventions than PTA alone through 24 months.

SUPERA stent placement for salvaging early recurrent arteriovenous graft thrombosis after percutaneous transluminal angioplasty: A single-center study.

The aim of this study was to evaluate the patency of the helical interwoven SUPERA stent for salvaging prosthetic arteriovenous (AV) grafts with rapidly recurrent thrombotic occlusion developed within a short time period after successful percutaneous transluminal angioplasty. From December 2019 to September 2021, the data of 20 patients with AV graft who had the SUPERA stent inserted satisfying the following conditions were consecutively collected. (1) More than 1 year has passed since the AV access operation; (2) Thrombotic re-occlusion of AV graft occurred within 3 months after previous successful endovascular treatment; (3) Residual stenosis is greater than 30% after full effacement of balloon angioplasty in the primary lesion. Post-interventional target lesion primary patency (TLPP), access circuit primary patency (ACPP), and secondary patency (SP) were calculated. Primary lesions of early recurrent arteriovenous graft thrombosis were found in 13 patients with graft-vein anastomosis, six patients with intra-graft stenosis, and one patient with outflow vein complications. The lesions showed residual stenosis in 47.4% (interquartile range: 44.1%-55.3%) of patients despite full-effacement balloon angioplasty. Clinical success was achieved in all patients with full-expansion of the stents at the 1-month follow-up. The TLPP was 70.7% and 32% at 6 and 12 months, respectively, and ACPP was 47.5% and 6.8% at 6 and 12 months, respectively. The SP was 76.1% and 57.1% at 6 and 12 months, respectively. No cannulation complications occurred in the six patients with installation inside the graft. No hemodialysis or stent fracture occurred in any patient during the follow-up period. The SUPERA stent may have a role in salvaging AV grafts with early recurrent thrombosis due to its greater radial force and its conformability and can be useful in treating stenosis involving the elbow or axilla, with fair patency and low complication rates.

Sirolimus-coated balloon angioplasty in maintaining the patency of thrombosed arteriovenous graft: 1-year results of a prospective study.

A prospective, pilot study was designed to test the feasibility of using sirolimus-coated balloon (SCB) to treat graft vein junction of thrombosed arteriovenous graft (AVG) following successful pharmacomechanical thrombectomy. The present report provides the 1-year results of this study. This is a 1-year follow-up of a single, prospective, single-arm study that was conducted from 2018 to 2019 in 20 patients who presented to a tertiary institution with thrombosed AVG. The recruited patients received SCB angioplasty at the graft-vein junction following successful endovascular thrombectomy of a thrombosed AVG. One year after recruitment, there were three deaths, one AVG revision, and one AVG explantation among the participants recruited. The outcomes of 15 subjects at 1-year following the index procedure obtained from electronic medical records were re-examined. The 1-year access circuit primary patency rate was 40%, while assisted primary and secondary patency rates were 46.7% and 73.3%, respectively. A total of 16 interventions (4 angioplasties, 12 thrombectomies) were performed in 9 patients over the 12 months. Four AVGs were abandoned. The median number of interventions per patient was 1 (0-3) per year. Using Kaplan-Meier analysis, the mean estimated post-intervention access circuit primary patency was 230 (95% CI: 162-300) days, while access circuit assisted primary patency was 253 (95% CI: 187-320) days, and access circuit secondary patency was 292 (95% CI: 230-356) days. Sub-group analysis did not show a significant difference in the mean estimated primary patency between AVG with de novo and recurrent stenosis (245 days, 95% CI: 151-339 vs 210 days, 95% CI: 113-307; p = 0.29). SCB may help sustain the patency of thrombosed AVG following successful thrombectomy.

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.

IN.PACT AV Access Trial: Economic Evaluation of Drug-Coated Balloon Treatment for Dysfunctional Arteriovenous Fistulae Based on 12-Month Clinical Outcomes

PurposeTo study, from a U.S. payer’s perspective, the economic consequences of drug-coated balloon (DCB) versus standard percutaneous transluminal angioplasty (PTA) use for the treatment of stenotic lesions in dysfunctional hemodialysis arteriovenous fistulae. Materials and MethodsCost differences between DCBs and PTA at year 1 and beyond were calculated via 2 methods. The first approach used the mean absolute number of trial-observed access circuit reinterventions through 12 months (0.65 ± 1.05 vs 1.05 ± 1.18 events per patient for DCBs and PTA, respectively) and projected treatment outcomes to 3 years. The second approach was based on the trial-observed access circuit primary patency rates at 12 months (53.8% vs 32.4%) and calculated the cost difference on the basis of previously published Medicare cost for patients who maintained or did not maintain primary patency. Assumptions regarding DCB device prices were tested in sensitivity analyses, and the numbers needed to treat were calculated. ResultsUsing the absolute number of access circuit reinterventions approach, the DCB strategy resulted in an estimated per-patient savings of $1,632 at 1 year and $4,263 at 3 years before considering the DCB device cost. The access circuit primary patency approach was associated with a per-patient cost savings of $2,152 at 1 year and $3,894 at 2.5 years of follow-up. At the theoretical DCB device reimbursement of $1,800, savings were $1,680 and $2,049 at 2.5 and 3 years, respectively. The one-year NNT of DCB compared to PTA was 2.48. ConclusionsEndovascular therapy for arteriovenous access stenosis with the IN.PACT AV DCB can be expected to be cost-saving if longer follow-up data confirm its clinical effectiveness.

IN.PACT AV Access Randomized Trial: 12-Month Clinical Results Demonstrating the Sustained Treatment Effect of Drug-Coated Balloons

PurposeTo present the 12-month outcomes of the IN.PACT AV Access Study, a prospective, single-blind trial enrolling participants with obstructive de novo or restenotic native upper extremity arteriovenous dialysis fistula lesions treated with a drug-coated balloon (DCB) or percutaneous transluminal angioplasty (PTA). Materials and MethodsAfter successful high-pressure PTA, participants at 29 international sites were randomized 1:1 to treatment with an IN.PACT AV DCB (n = 170) or standard uncoated PTA (n = 160). Outcomes at 12 months include target lesion primary patency (TLPP), defined as freedom from clinically driven target lesion revascularization or access circuit thrombosis; access circuit primary patency; number of reinterventions; and adverse events involving the access circuit. ResultsAt 12 months, TLPP was 63.8% (90/141) in the DCB group compared with 43.6% (61/140) in the PTA group (P < .001). The total number of reinterventions required to maintain TLPP through 360 days was 93 in the DCB group and 144 in the PTA group, with a 35.4% reduction in reinterventions when DCB was used. Access circuit thrombosis occurred in 2.9% (4/138) of the participants in the DCB group and in 6.2% (8/129) of those in the PTA group (P = .19). Time to TLPP was assessed using a multivariable analysis to identify the factors associated with loss of patency. The treatment device was the independent predictor with the largest effect, with a hazard ratio of 0.42 (95% confidence interval, 0.29–0.60; P < .001). ConclusionsTLPP was statistically significantly higher with DCBs than with standard PTA at 12 months, demonstrating the sustained and superior effectiveness of this device for the treatment of dysfunctional arteriovenous dialysis fistulae.

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.

Long-term Results of Interwoven Nitinol Stents to Treat the Radiocephalic Anastomotic Arteriovenous Fistula Stenosis

Introduction: Juxta-anastomotic stenosis (JXAS) is a common problem afflicting the arteriovenous fistula (AVF). This study aimed to evaluate the safety and long-term efficacy of an interwoven nitinol stent (Supera, Abbott Vascular, Santa Clara, CA, USA) in the treatment of radiocephalic AVF JXAS. Methods: A single-center, retrospective, observational study was conducted of patients with failing AVF due to JXAS treated with an interwoven nitinol stent. End points included JXAS target lesion primary patency, access circuit primary patency, assisted access circuit primary patency, and endovascular intervention rate (EIR). Results: Sixty patients were treated with a Supera stent in the JXAS between February 2014 and March 2020. One patient was excluded (AVF used for illicit drug use), leaving 59 patients (67.8% male, mean age 66.9 ± 11.4 years [range: 40–84]) with typical medical comorbidities. Overall, 45.8% of patients had previous AVF intervention. The stent was inserted with a 100% technical success rate with a mean follow-up of 729.6 ± 456.0 days (range: 5–2182 days). Juxta-anastomotic stenosis target lesion primary patency was 68.2 ± 6.6%, 53.3 ± 7.5%, and 46.2 ± 8.1% at 12, 24, and 36 months, respectively. The EIR was .64 (0–3.29) procedures/patient/year, after which the assisted access circuit primary patency rate was 94.3 ± 3.2% at 12, 24, and 36 month time points. Three thrombosed circuits occurred which were all successfully salvaged with no difference in patency by indication for procedure and no AVFs lost/abandoned out to 3 years. Avoidance of stent post-dilatation and the presence of stent mal-apposition were associated with improved primary patency, and reduced EIR, which may suggest an importance in vessel preparation prior to stent implantation. Conclusion: Interwoven nitinol stent treatment of the failing AVF with JXAS results in promising 3 year JXAS patency, with a low rate of endovascular re-intervention for those circuits developing restenosis. All AVFs were maintained over 3 years, demonstrating this treatment allows for long-term radiocephalic AVF vascular access.

SIroliMus coated angioPlasty versus plain balloon angioplasty in the tREatment of dialySis acceSs dysfunctION (IMPRESSION): study protocol for a randomized controlled trial

BackgroundPercutaneous transluminal angioplasty is the current standard treatment for arteriovenous fistula (AVF) stenosis. The mid- and long-term patency with plain balloon angioplasty (PBA) is however far from satisfactory. While paclitaxel-coated balloon angioplasty has been shown to be superior to PBA, concern over its safety profile has recently arisen after a reported possible increased mortality risk with a meta-analysis of large lower limb studies. An angioplasty balloon with a new type of drug coating, the sirolimus-coated balloon (SCB), has been proven to improve patency in the coronary arteries. However, its effect on AV access has yet to be studied.Methods/designThis is an investigator-initiated, prospective, multicenter, double-blinded, randomized controlled clinical trial to assess the effectiveness of SCB compared to PBA in improving the patency of AVF after angioplasty. A total of 170 patients with mature AVF that requires PTA due to AVF dysfunction will be randomly assigned to treatment with a SCB or PBA at a 1:1 ratio, stratified by location of AVF and followed up for up to 1 year. The inclusion criteria include [1] adult patient aged 21 to 85 years who requires balloon angioplasty for dysfunctional arteriovenous fistula [2]; matured AVF, defined as being in use for at least 1 month prior to the angioplasty; and [3] successful angioplasty of the underlying stenosis with PBA, defined as less than 30% residual stenosis on digital subtraction angiography (DSA) and restoration of thrill in the AVF on clinical examination. The exclusion criteria include thrombosed or partially thrombosed access circuit at the time of treatment, presence of symptomatic or angiographically significant central vein stenosis that requires treatment with more than 30% residual stenosis post angioplasty, and existing stent placement within the AVF circuit. The primary endpoint of the study is access circuit primary patency at 6 months. The secondary endpoints are target lesion primary patency; access circuit-assisted primary patency; access circuit secondary patency at 3, 6, and 12 months; target lesion restenosis rate at 6 months; total number of interventions; complication rate; and cost-effectiveness. The trial is supported by Concept Medical.DiscussionThis study will evaluate the clinical efficacy and safety of SCB compared to PBA in the treatment of AVF stenosis in hemodialysis patients.Trial registrationClinicalTrials.govNCT04409912. Registered on 1 June 2020

Drug-coated balloon angioplasty for failing haemodialysis access: meta-analysis of randomized clinical trials.

Arteriovenous fistulas, a major treatment for end-stage kidney disease, frequently require endovascular reinterventions to maintain haemodialysis function. Drug-coated angioplasty balloons (DCBs) were developed with the intention of reducing reintervention rates. The aim of this study was to perform a systematic review and meta-analysis of DCBs in the treatment of failing haemodialysis access. Electronic databases were searched systematically to identify all relevant RCTs and any follow-up studies from RCTs. Pooled estimates of dichotomous outcomes were calculated using the odds ratio (OR) and 95 per cent confidence interval. Effect data are presented as summary hazard ratio and 95 per cent confidence interval. Some 19 studies from 18 RCTs and comprising 1898 patients were included in the meta-analysis. Compared with plain balloon angioplasty (PBA), DCB use was associated with higher target-lesion primary patency (HR 0.60, 95 per cent c.i. 0.45 to 0.79), access-circuit primary patency (HR 0.67, 0.56 to 0.80), and less target-lesion revascularization (TLR) within 6 months (OR 0.33, 0.23 to 0.47). No difference was observed between DCB and PBA in 12-month TLR (OR 0.62, 0.28 to 1.37). Mortality after DCB use was similar to that associated with PBA use at 6 months (OR 1.20, 0.65 to 2.21) and 12 months (OR 0.99, 0.66 to 1.49), and was higher at 24 months (23.1 versus 16.6 per cent), although the difference was not statistically significant (OR 1.53, 0.92 to 2.53). Drug-coated balloon angioplasty of haemodialysis fistulas is associated with higher patency rates and lower rates of reintervention in the short to mid term. Although mortality rates appeared to be higher with drug-coated angioplasty at 24 months, this did not reach statistical significance.

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.

Paclitaxel-assisted balloon angioplasty of venous stenosis in haemodialysis access: PAVE RCT

Background Reliable vascular access is essential for patients receiving haemodialysis. An arteriovenous fistula is the preferred option; however, these are prone to developing stenotic segments. These lesions are treated with angioplasty, but there is a high rate of recurrence. When the PAVE (Paclitaxel-assisted balloon Angioplasty of Venous stenosis in haEmodialysis access) trial was conceived, a number of small studies suggested that restenosis may be reduced by paclitaxel-coated balloons. Objective To test the efficacy of paclitaxel-coated balloons in arteriovenous fistulas. Design A randomised controlled trial. Setting Twenty UK centres. Participants Patients (aged ≥ 18 years) referred with a clinical indication for angioplasty of an arteriovenous fistula (212 patients in total, 106 per group). Interventions High-pressure plain balloon fistuloplasty was performed in all patients. In the intervention arm, the second component was insertion of a paclitaxel-coated balloon. In the control arm, an identical procedure was followed, but using a standard balloon. Main outcome measures The primary end point was time (days) to loss of target lesion primary patency. Secondary patency end points were time to loss of access circuit primary patency and time to loss of access circuit cumulative patency. Other secondary end points included angiographically determined late lumen loss, rate of binary angiographic restenosis, procedural success, number of thrombosis events, fistula interventions, adverse events during follow-up and patient quality of life. Results Primary analysis showed no evidence for a difference in time to end of target lesion primary patency between groups (hazard ratio 1.18, 95% confidence interval 0.78 to 1.79; p = 0.440). An adjusted secondary analysis with prespecified clinical covariates gave similar results (hazard ratio 1.11, 95% confidence interval 0.69 to 1.78; p = 0.664). Prespecified secondary outcomes included the time to intervention anywhere in the access circuit or the time until the fistula was abandoned. There were no differences in these patency-related secondary outcomes or in any other secondary outcomes, such as adverse events. Limitations The PAVE trial was not a fully blinded trial. It was impossible to ensure that treating radiologists were blinded to treatment allocation because of the appearance of the paclitaxel-coated balloon. The extent to which our findings can be generalised to patients with multiple lesions could be questioned, given the proportion randomised. However, if paclitaxel-coated balloons had been effective at a single lesion segment, then there is no plausible reason why they could not be effective in patients with multiple lesions. Conclusions There were no differences in primary or secondary outcomes. Following a plain balloon angioplasty, additional treatment with a paclitaxel-coated balloon does not provide benefit. Future work The reasons for differences between the results of the PAVE trial and of other studies deserve further analysis and consideration. Other interventions to prevent restenosis following a fistuloplasty are needed. Trial registration Current Controlled Trials ISRCTN14284759. Funding This project was funded by the Efficacy and Mechanism Evaluation programme, a Medical Research Council and National Institute for Health Research (NIHR) partnership. This will be published in full in Efficacy and Mechanism Evaluation; Vol. 8, No. 13. See the NIHR Journals Library website for further project information.

Covered stents versus balloon angioplasty for failure of arteriovenous access: a systematic review and meta-analysis

IntroductionPatients with end-stage renal disease may require arteriovenous (AV) access in the form of arteriovenous fistulae (AVFs) or arteriovenous grafts (AVGs) for haemodialysis. AV access dysfunction requires intervention such as...