Quality Improvement Guidelines for Percutaneous Image-Guided Management of the Thrombosed or Dysfunctional Dialysis Circuit

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

PURPOSE

To evaluate the safety and performance of Wrapsody™, a cell-impermeable endoprosthesis (CIE), for treating hemodialysis vascular access outflow stenosis.

MATERIALS AND METHODS

Investigators retrospectively analyzed 113 hemodialysis patients treated with a CIE (11/2021-12/2022) across four centers in Brazil. De novo or restenotic lesions were treated. The primary efficacy outcome measure was target lesion primary patency (TLPP) at 1, 3, 6, and 12 months; the primary safety outcome measure was the absence of serious local or systemic adverse events within the first 30 days post-procedure. Secondary outcome measures included technical and procedural success, access circuit primary patency (ACPP), and secondary patency at 1, 3, 6, and 12 months post-procedure.

RESULTS

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 12 months were 100%, 96.4%, 86.4%, and 69.7%, respectively. ACPP rates were 100% at 1 month, 89.2% at 3 months, 70.9% at 6 months, and 56.0% at 12 months. The target lesion secondary patency rates at 1, 3, 6, and 12 months 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 16 mm were associated with improved primary patency rates. No localized or systemic serious adverse event was observed through the first 30 days post-procedure.

CONCLUSION

The CIE evaluated in this study is safe and effective for treating peripheral and central outflow stenoses in hemodialysis vascular access.

LEVEL OF EVIDENCE

Level 2b, cohort study.

Association of radiocephalic arteriovenous anatomical markers with post-angioplasty blood flow volume

BACKGROUND

Doppler ultrasound (DUS) blood volume flow (VF) calculation is the most reliable method for demonstrating the success of endovascular treatment of dysfunctional radiocephalic arteriovenous fistula (AVF). Due to the difficulty of this method for the interventionalist, VF-correlated markers are required during the procedure.

PURPOSE

To investigate the relationship between intraprocedural anatomical markers (AMs) and changes in VF induced by percutaneous transluminal angioplasty (PTA).

MATERIAL AND METHODS

The study included 56 patients with dysfunctional radiocephalic AVF who underwent PTA between September 2020 and 2022. The VF of all patients was measured using DUS before and 1 h after PTA. AMs were determined from 10 images, five before and five after balloon angioplasty.

RESULTS

The mean post-PTA VF was 637 ± 277 mL/min compared to baseline (151 ± 107 mL/min). Before and after balloon angioplasty, vein diameter (VD), artery diameter (AD), stenosis minimum luminal diameter (MLD), stenosis percentage (SP), and VF values were statistically significant (P = 0.001). Spearman's correlation analysis showed a positive strong linear relationship between VF and MLD (rs = 0.850, P <0.001), and a negative strong linear relationship between VF and SP (rs = 0.815). Receiver operating characteristic curve analysis showed that the sensitivity and specificity for VF ≥400 mL/min at cutoffs of SP <50% and MLD >2.5 mm were 81% and 82%, and 81% and 90%, respectively.

CONCLUSION

Among the AMs readily available during PTA, first MLD and then SP provided satisfactory results in predicting VF.

Long-term outcomes following thrombolysis of arteriovenous grafts

BACKGROUND

Thrombolysis for arteriovenous grafts (AVG) yields high technical success rates, however, long-term outcomes are unclear. We conducted a multicenter retrospective cohort study to analyze 5-year patency rates following AVG thrombolysis.

METHODS

All patients who underwent AVG thrombolysis between 2005 and 2015 at three academic hospitals were included. Prospectively maintained institutional nephrology and radiology databases were used to record demographic, clinical, and AVG characteristics. The primary outcome was primary patency, defined as AVG access survival without re-intervention including angioplasty ± stent with/without re-thrombolysis. Secondary outcomes were assisted primary patency and cumulative patency, defined as AVG access survival until re-thrombosis requiring re-thrombolysis or abandonment, respectively. Technical success was defined as restoration of flow with <30% residual stenosis. Patients were followed until 2017. Patency rates were assessed using Kaplan-Meier survival analysis and Cox proportional hazards were calculated to determine associations between covariates and patency loss.

RESULTS

Seventy-four patients underwent AVG thrombolysis during the study period with a median follow-up period of 21.4 (IQR 8.3-42.8) months. The average age was 58.6 years with a high rate of comorbidities, including hypertension (82.4%) and diabetes (54.1%). Thrombolysis technical success was 96%. There were 147 re-interventions in 46 patients, of which 98 were re-thrombolysis (mean re-intervention rate of 1.27/patient/year). Primary patency at 1, 3, and 5 years were 43.2%, 20.2%, and 7.7%. Assisted primary patency at 1, 3, and 5 years were 47.5%, 20.2%, and 7.7%. Cumulative patency at 1, 3, and 5 years were 75.0%, 38.8%, and 22.6%. Cox proportional hazards analysis demonstrated no associations between demographic, clinical, and procedural characteristics and patency rates.

CONCLUSIONS

Despite a high technical success rate, thrombolysis for AVG dysfunction is associated with poor long-term patency. Future studies are needed to determine risk factors for re-thrombosis to identify patients who will benefit from AVG thrombolysis in the long-term.

Comparison of pharmacological thrombolysis with mechanical thrombectomy in thrombosed arteriovenous fistulas and grafts: a systemic review and meta-analysis

AIM

To compare the effectiveness and safety of pharmacological thrombolysis and mechanical thrombectomy.

MATERIAL AND METHODS

This review was conducted in accordance with the PRISMA guidelines. Pooled proportions and subgroup analysis were calculated for primary and secondary patency rates, technical success, clinical success, major and minor complications rates.

RESULTS

This systematic review identified a total of 6,492 studies of which 17 studies were included for analysis. A total of 1,089 patients comprising 451 (41.4 %) and 638 (58.6 %) patients who underwent thrombolysis and mechanical thrombectomy procedures, respectively, were analysed. No significant differences were observed between thrombolysis and mechanical thrombectomy procedures in terms of technical success, clinical success, major and minor complications rates, primary and secondary patency rates; however, subgroup analysis of overall arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) demonstrated a significantly higher rate of major complications within the AVF group (p=0.0248).

CONCLUSION

The present meta-analysis suggests that pharmacological thrombolysis and mechanical thrombectomy procedures are similarly effective and safe; however, AVFs are subject to higher major complications compared to AVGs.

Percutaneous Management of Dialysis Access Steal Syndrome: Interventions and Outcomes from a Single Institution's 20-Year Experience

PURPOSE

To determine safety and effectiveness of percutaneous interventions performed by interventional radiologists at a single institution over 2 decades in patients with dialysis access steal syndrome (DASS).

MATERIALS AND METHODS

A retrospective review of fistulograms from 2001 to 2021 (N = 11,658) was performed. In total, 286 fistulograms in 212 patients with surgically created dialysis accesses met inclusion criterion of fistulography for suspected DASS. Chart review collected data regarding patient demographics, comorbidities, access characteristics, fistulography findings, intervention(s) performed, and outcomes. Procedures with and without DASS intervention were compared. Odds ratios (ORs), adjusted for age, sex, comorbidities, access characteristics, and multiple within-patient events, were calculated using logistic regression to determine associations between steal intervention status and outcome variables: (a) major adverse events, (b) access preservation, and (c) follow-up surgery. A percutaneously treatable cause of DASS was present in 128 cases (45%). Treatment of DASS lesions was performed in 118 cases. Fifteen embolizations were also performed in patients without DASS lesions.

RESULTS

Technical success of DASS interventions, defined by the Society of Interventional Radiology (SIR) reporting standards, was 94%; 54% of interventions resulted in DASS symptom improvement at a median follow-up of 15 days. Patients with steal intervention had 60% lower odds of follow-up surgery (OR, 0.4; P = .007). There was no difference in major adverse events (P = .98) or access preservation (P = .13) between groups.

CONCLUSIONS

In this retrospective cohort study, approximately half of DASS fistulograms revealed a percutaneously treatable cause of steal. Over half of DASS interventions resulted in symptomatic relief. Percutaneous intervention was associated with lower odds of follow-up surgery without compromising access preservation.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

In this retrospective analysis, a new covered stent was shown to be safe and effective for treating peripheral outflow stenosis in vascular access.

Transjugular approach: comparison with conventional endovascular treatment of native arteriovenous fistulas

OBJECTIVES

The aim of this study was to compare the outcomes of the transjugular approach with those of the conventional approach for endovascular treatment of arteriovenous fistulas (AVFs).

METHODS

Between May 2015 and July 2019, 112 patients with endovascular treatment of dysfunctional or immature AVFs were included and divided into the transjugular (n = 46) and conventional (n = 66) groups. Electronic medical records and angiography of the patients were retrospectively reviewed to assess technical and clinical success rates, time to first fistulography, total procedure time, primary and secondary patency, and complications in both groups.

RESULTS

There were no significant differences in technical success rate (87.0% vs 97.0%; P = .062), clinical success rate (80.4% vs 90.9%; P = .109), or total procedure time (60.2 vs 57.9 min; P = .670) between the groups. Cox proportional hazards models showed that the cumulative primary patency was significantly higher in the transjugular group than in the conventional group (P = .041; 6-month patency rates, 93.8% vs 91.5%). Also, a statistically significant difference was found between the cumulative secondary patency of the groups (P = .014; 6-month patency rates, 91.4% vs 86.5%). No major complications were observed.

CONCLUSIONS

Transjugular endovascular treatment of AVFs was successful and effective. Longer patency periods were observed when treated via transjugular access.

ADVANCES IN KNOWLEDGE

This article compared the outcomes of transjugular approaches with those of conventional approaches in the endovascular treatment of native AVFs and showed higher patency periods/rates in the transjugular group than in the conventional group.

The role of vacuum-assisted mechanical thrombectomy in the management of acutely thrombosed arteriovenous fistulas and grafts

PURPOSE

The purpose of this study is to evaluate the safety and efficacy of the mechanical thrombectomy with the Indigo System in the treatment of thrombosed arteriovenous fistulas and grafts.

METHODS

A retrospective search of endovascular procedures performed from November 2018 to June 2020 was conducted. Inclusion criteria were: acute arteriovenous fistula or graft thrombosis that underwent endovascular mechanical thrombectomy with Indigo System. The following information was collected from each case: sex, age, fistula modality, fistula location, treatment modality, and outcomes. Endpoints evaluated were: technical and clinical success rates; primary, assisted primary, and secondary patency rates; complication rates.

RESULTS

Twenty-six mechanical thrombectomy procedures for declotting of arteriovenous fistula thrombosis, using the Indigo System, were performed in 22 patients. Technical and clinical success was achieved in 23/26 cases (88%). Mean follow-up was 9 months (range 11-539 days). The 6-month primary, primary assisted, and secondary patency rates were 71%, 86%, 93% and the 12-month primary, primary assisted, and secondary patency rates were 71%, 72%, 80%, respectively. No technical or device-related complications were observed during thrombectomy, however two venous ruptures occurred on the angioplasty of the underlying stenosis.

CONCLUSION

In conclusion, vacuum-assisted thrombectomy of acutely thrombosed arteriovenous fistulas and grafts with Indigo System is safe and effective, providing good short term patency rates.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

SCB may help sustain the patency of thrombosed AVG following successful thrombectomy.

Duplex ultrasound-guided angioplasty of hemodialysis vascular access

OBJECTIVE

Duplex ultrasound-guided angioplasty (DA) for hemodialysis vascular accesses remains questionable regarding its feasibility and safety. Minor complications (requiring no more treatment than nominal therapy) might be over-reported. Our hypothesis is that this procedure has no significant differences between observed rates and the recommended threshold of main outcomes of the procedure defined by the standards of arteriovenous fistulas (AVF) angioplasty.

METHODS

In a single-center retrospective study, 298 DA performed on 141 patients from 2015 to 2019 were analyzed. Occluded AVF or concomitant use of radiographic guidance were excluded. Duplex ultrasound parameters were collected up to 1 month before, at the end of angioplasty, and on day 30 after the procedure. Complications were registered, and patency rates were studied at 24 months of follow-up.

RESULTS

Anatomical success was achieved in 142 procedures (47.7%), clinical success in 284 (95.3%), and hemodynamic success in 283 (95.0%). Major complications-requiring at least a specific therapy-were reported in 8 procedures (2.7%) and minor complications-requiring no adjunctive therapy-in 157 (52.7%). At 24 months, overall postintervention primary patency was 34.0%, primary-assisted patency 87.4%, and secondary patency 92.5%. There were no significant differences of patency rates between groups with or without minor complications (P value for primary patency, 0.08; primary-assisted patency, 0.08; secondary patency, 0.23) or 30% residual stenosis (P value for primary patency, 0.82; primary-assisted patency, 0.46; secondary patency: 0.63). Duplex parameters further improved at postoperative day 30 after angioplasty.

CONCLUSIONS

DA of AVF is feasible, safe-despite over-reported minor complications having no impact on postintervention patency rates-and efficient. A minor complication can be seen as an event without bad or good consequences. Anatomical definition of success does not fit on DA for hemodialysis vascular access. Further studies are required to define the duplex parameter threshold for efficacy.

ACR Appropriateness Criteria® Dialysis Fistula Malfunction

The creation and maintenance of a dialysis access is vital for the reduction of morbidity, mortality, and cost of treatment for end stage renal disease patients. One's longevity on dialysis is directly dependent upon the quality of dialysis. This quality hinges on the integrity and reliability of the access to the patient's vascular system. All methods of dialysis access will eventually result in dialysis dysfunction and failure. Arteriovenous access dysfunction includes 3 distinct classes of events, namely thrombotic flow-related complications or dysfunction, nonthrombotic flow-related complications or dysfunction, and infectious complications. The restoration of any form of arteriovenous access dysfunction may be supported by diagnostic imaging, clinical consultation, percutaneous interventional procedures, surgical management, or a combination of these methods. This document provides a rigorous evaluation of how variants of each form of dysfunction may be appraised and approached systematically. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Longitudinal micro-incision creation prior to balloon angioplasty for treatment of arteriovenous access dysfunction in a real-world patient population: 6-month cohort analysis

INTRODUCTION

Routine hemodialysis depends on well-functioning vascular access. In the event of vascular access dysfunction, percutaneous transluminal balloon angioplasty (PTA) is conducted to restore patency. Although an angioplasty procedure can provide an excellent immediate result by opening the access to allow dialysis to continue, the long-term patency rates are less than satisfactory. The goal of this study was to assess the outcomes of patients who underwent a novel vessel preparation via longitudinal, controlled-depth micro-incisions prior to PTA.

METHODS

This multicenter, prospective, observational registry enrolled hemodialysis patients scheduled to undergo PTA of their arteriovenous fistula or graft due to clinical or hemodynamic abnormalities. A primary endpoint was anatomic success, defined as angiographic confirmation of <30% residual stenosis post-procedure without an adverse event. Additional assessments included device technical success, clinical success, freedom from target lesion revascularization, target lesion primary patency, and circuit primary patency at 6 months.

FINDINGS

A total of 148 lesions were treated with the FLEX Vessel Prep™ System (FLEX VP) prior to PTA in 114 subjects at eight clinical sites. Target lesions were 21 ± 25 mm in length with mean pre-procedure stenosis of 75.2% ± 4.7%. Five procedural complications were recorded without serious adverse events. Two subjects did not complete the follow-up evaluation. Target lesion primary patency across all subjects at 6-months was 62.2% with mean freedom from target lesion revascularization of 202.7 days. Target lesion primary patency and freedom from target lesion revascularization for AVF cases (n = 72) were 67.5% and 212.9 days, respectively. Target lesion primary patency and freedom from target lesion revascularization for AVGs (n = 42) were 52.4% and 183.3 days, respectively. In cases treating AVF cephalic arch stenosis (n = 25), 6-month target lesion primary patency was 70.6% and freedom from target lesion revascularization was 213.4 days.

DISCUSSION

This FLEX-AV registry demonstrates safety and effectiveness, notably in the cephalic arch and AVGs, when FLEX VP is used prior to PTA for treatment of vascular access dysfunction in a population of end-stage renal disease subjects.

Management of Central Venous Stenoses and Occlusions

Symptomatic central venous stenosis and occlusion remains the gordian knot of vascular access. Advances in techniques, like sharp recanalization, allowed for improved success rates in crossing these difficult lesions. There is also increasing evidence of new devices in treating central venous stenosis and, at the same time, improving the time needed between interventions. High-pressure balloons, paclitaxel-coated balloons, bare metal stents and covered stents have been tested with an aim to offer additional treatment options, although obstacles still exist. In the current review, authors describe relevant techniques and options, provide the evidence and evaluate the actual implementation of these devices in this demanding field.

Single-centre experience with endovascular rotational thrombectomy for single session salvage of thrombosed arteriovenous fistulas and grafts

OBJECTIVES

This paper documents our experience and outcomes of using a relatively new endovascular rotational thrombectomy device for salvage of thrombosed vascular access.

METHODOLOGY

A retrospective study reviewing patients with thrombosed native AVF or AVG who underwent endovascular declotting using a rotational thrombectomy device between November 2018 and May 2020 at a tertiary university hospital in Southeast Asia. We evaluated demographics, procedural data, technical and procedural success, patency rates and complications.

RESULTS

A total of 40 patients underwent single session endovascular declotting of thrombosed vascular access. The mean follow-up period was 21.6 months (range 13.4-31 months). The technical success was 92.5% and clinical success was 80%. About 50% of patients had concomitant thrombolysis for pharmacomechanical thrombectomy. One patient had a myocardial infarction during the post-operative period. There were no other major complications within 30 days. The primary patency was 45.5% at 6 months and 22.7% at 12 months. Assisted primary patency was 68.1% at 6 months and 61.6% at 12 months, which was maintained up to 2 years. The secondary patency was 84.1% at 6 and 12 months.

CONCLUSION

Our study shows that rotational thrombectomy device for single session thrombectomy of thrombosed arteriovenous fistulas and grafts is safe and effective. A high technical and clinical success rate was achieved, with low complication rates and specific advantages compared to other techniques, including reduced length of hospital stay. Our reported mid-term outcomes are reasonable with an assisted primary patency of 62% at 12 and 24 months. The use of newer techniques and novel dedicated thrombectomy devices show promise.

Prospective, Multicenter, Observational Study to Evaluate a Cell-Impermeable Endoprosthesis for Treatment of Stenosis or Occlusion within the Dialysis Outflow Circuit of an Arteriovenous (AV) Fistula or AV Graft (The WRAP Registry)

PURPOSE

Dysfunctional vascular access due to stenosis/occlusion within the arteriovenous fistula or graft (AVF/AVG) negatively affects the clinical management of patients undergoing hemodialysis. Results from the feasibility study of the WRAPSODY™ Cell-Impermeable Endoprosthesis demonstrated that the device can achieve high patency rates and maintain integrity of the dialysis outflow circuit. This study was designed to assess real-world evidence of safety and efficacy outcomes following device placement.

MATERIALS AND METHODS

This is a prospective, multicenter, non-investigational, post-market observational study of 500 patients at up to 50 centers worldwide with a mature AVF/AVG dialysis access (≥ 1 hemodialysis session) who experience stenosis/occlusion of the outflow circuit prior to placement of WRAPSODY. Patients will be divided into the following two cohorts: peripheral or central thoracic. Primary outcome measures include target lesion primary patency (TLPP) at 6 months and procedure and/or device-related events through 30 days post-procedure. Secondary outcome measures include TLPP, safety events, and the number of interventions needed to maintain patency through the 24 month study period. Exploratory endpoints include time to access abandonment, resumption of successful dialysis, functional patency, and pending available imaging data, any incidence of stent fractures, migration, or edge stenosis. Study enrollment began in June 2022, the last patient visit is expected in 2026.

DISCUSSION

It is expected that this study will provide real-world evidence regarding the performance of the WRAPSODY device in a diverse population of patients, which may encourage its use in the continuum of hemodialysis access management.

TRIAL REGISTRATION

NCT05062291.

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

OBJECTIVE

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.].

Oversized balloon angioplasty for endovascular maturation of arteriovenous fistulae to accelerate cannulation and to decrease the duration of catheter use

BACKGROUND

The functional autologous arteriovenous fistula is considered the best vascular access for patients on hemodialysis. Some fistulae exhibit maturation problems after creation and do not reach adequate vessel diameter and flow in dialysis. The aim of this study was to describe our technique of oversized balloon angioplasty for assisted maturation of arteriovenous fistulae to accelerate the cannulation and to decrease the time of catheter use and its outcome.

METHODS

A retrospective analysis of balloon-assisted procedures for maturation failure was performed in a single center between October 2011 and January 2019. Patients underwent imaging procedures to identify stenosis, followed by angioplasty using oversized high-pressure balloons from the anastomosis to the deep venous outflow tract. The flow volume, time interval of use of the fistula and removal of the catheter, patency rates, and complications rates were evaluated.

RESULTS

Seventy-eight patients underwent 124 balloon angioplasty procedures. Technical and clinical success was achieved in 91% of the cases. In patients in whom maturation was successful, the fistula was cannulated in a mean time of 5 days after the procedure (range, 1-20 days). On average, catheter removal was performed 14 days (range, 5-33 days) after the maturation procedure. The mean flow volume in the fistula before the procedure was 276 ml/min (range, 122-488 ml/min) and 24 h after the maturation was 1014 ml/min (range, 760-1800 ml/min).The primary patency rate at 3, 6, and 12 months was 87.3%, 66.2%, and 50.7%, respectively. Assisted primary patency was 100% at 3 months, 92.9% at 6 months, and 90.0% at 12 months. Minor complications occurred in 18% of cases, and major complications in 4.8%.

CONCLUSIONS

The oversized balloon-assisted arteriovenous fistula maturation technique is safe and effective, allowing the cannulation of the fistulae a few hours or days after the procedure and decreasing the time of catheter use.

Chameleon™ PTA balloon catheter: A single device in managing thrombosed AV access

Thrombectomy is a common procedure for maintenance of arteriovenous (AV) access and is critical to prolong access life. Techniques for performing thrombectomy are incredibly diverse, ranging from open surgical procedures to percutaneous interventions. Percutaneous interventions include a combination of thrombectomy devices to clear the thrombus and balloon angioplasty to treat the underlying lesion. In this case report we describe a novel technique using a single device, the Chameleon™ PTA balloon catheter (Medtronic, Minneapolis, MN) balloon catheter, to safely and efficiently perform a percutaneous intervention.

Direct Percutaneous Thrombolysis (DPT): A novel method of salvaging Thrombosed Native Arteriovenous Fistula

INTRODUCTION

Thrombosed arteriovenous fistulas (AVFs) are either treated by thrombectomy or pharmaco-mechanical thrombolysis with or without percutaneous balloon angioplasty. In this study, we have described an effective and economical technique of salvaging these fistulae using a 20-22-gauge spinal needle and urokinase and have named it direct percutaneous thrombolysis (DPT).

MATERIALS AND METHOD

This prospective study comprised of 148 patients out of which 120 patients presented with AVF thrombosis and were divided into two groups; those with no obvious stenosis on ultrasound (n = 38) and second with venous stenosis (n = 82). Remaining 28 patients developed thrombosis post angioplasty for venous stenosis. Percutaneous injection of urokinase into the thrombus was done under ultrasound guidance, followed by balloon angioplasty if there was associated stenosis.

RESULTS

In 38 patients who didn't have any stenosis, 32 AVFs were successfully thrombolysed by DPT, with technical success of 84.2%. Remaining six patients required angioplasty because of chronic nature of clot. In 82 patients who had venous stenosis, 80 cases were treated successfully by DPT followed by angioplasty with technical success of 97.5%. In third group (n = 28), who developed thrombosis post angioplasty, 100% success rate was noted. The mean length of thrombus was 31.4 ± 4.6 mm and mean diameter of thrombosed vein was 10.5 ± 1.2 mm. There were no major complications encountered during the procedure. Minor complications were seen in 19 patients which included prolonged oozing from puncture site and local hematoma formation.

CONCLUSION

Ultrasound guided DPT with urokinase is a safe and economical option for salvaging thrombosed AVF without vascular stenosis that does not need angioplasty.

Comparing Patency Rates of Arteriovenous Dialysis Access following Percutaneous Thrombectomy Using Various Catheter Directed Therapies

BACKGROUND

Arteriovenous fistulas often require frequent interventions to maintain patency for hemodialysis. Interventions may include open or percutaneous thrombectomy with additional targeted interventions as indicated. We evaluated the primary and cumulative functional patency rates following three unique approaches to percutaneous thrombectomy of thrombosed dialysis access.

METHODS

A retrospective review of 236 unique patients who presented with thrombosed hemodialysis access was analyzed over a period of 4 years from 2016 to 2020. We analyzed a total of 413 procedures that utilized 3 separate percutaneous thrombectomy devices to assist with restoring patency. The Indigo System CAT-D Aspiration Thrombectomy Catheter (Penumbra; Alameda, CA), the Arrow-Trerotola Rotational Thrombectomy System (Teleflex; Wayne, PA) and the Angiojet Rheolytic Thrombectomy Catheter (Boston Scientific, Marlborough, MA) devices were compared for primary and cumulative functional patency. Primary patency was defined as time from percutaneous thrombectomy to next intervention (Angioplasty, stenting, and repeat thrombectomy). Cumulative functional patency was defined as time from percutaneous thrombectomy to time of access abandonment. Medical record chart review was utilized to determine patency rates.

RESULTS

A total of 413 percutaneous thrombectomy procedures were performed. Of the procedures performed, 98 utilized Angiojet, 103 utilized Trerotola, and 212 used Penumbra. The mean primary patency rates in (days) for the devices were as follows: Angiojet (194), Trerotola (204), and Penumbra (107). The mean cumulative functional patency rates (in days) for the devices were as follows: rheolytic thrombectomy (450 days), aspiration thrombectomy (292 days), and rotational thrombectomy (475 days). Angiojet versus Penumbra and Trerotola versus Penumbra both showed diminished patency rates when using the Penumbra catheter that were statistically significant (P < 0.05).

CONCLUSIONS

All percutaneous thrombectomy approaches do not result in the same primary or cumulative functional patency rates. Approaches with Trerotola and Angiojet resulted in improved primary and cumulative functional patency rates compared to those using Penumbra.

Design of a High-Flow Catheter Connector to Enhance Fluid Transfer

PURPOSE

To compare the performance of a prototype high-flow catheter connector, the Lamprey Lock, with that of a conventional Luer connector.

MATERIALS AND METHODS

The Lamprey Lock was created to eliminate the choke point resulting from Luer connections by achieving a cross-sectional area approximately 2.5 times larger than that achieved by a conventional Luer connector. A Lamprey Lock 3-way connector was also created by expanding the inner channels of a traditional Luer 3-way connector and exchanging the male Luer connection with a Lamprey Lock connection. These were tested against unaltered Luer and Luer 3-way connectors to compare flow rates using in vitro models of serous and purulent fluid. Each experimental condition was repeated 5 times.

RESULTS

In the serous model, the mean drainage rate was 4.4 mL/s (95% CI, 4.3-4.6) and 3.3 mL/s (95% CI, 3.3-3.5) for the Lamprey Lock and Luer connector, respectively (P < .001). The mean drainage rate was 4.2 mL/s (95% CI, 3.9-4.5) and 2.7 mL/s (95% CI, 2.5-2.8) for the Lamprey Lock 3-way and Luer 3-way connector, respectively (P < .001). In the purulent model, the mean drainage rate was 1.4 mL/min (95% CI, 1.3-1.6) and 0.75 mL/min (95% CI, 0.68-0.82) for the Lamprey Lock and Luer connector, respectively (P < .001). The mean drainage rate was 1.5 mL/min (95% CI, 1.3-1.7) and 0.74 mL/min (95% CI, 0.70-0.78) for the Lamprey Lock 3-way and Luer 3-way connector, respectively (P < .001).

CONCLUSIONS

The proposed high-flow catheter connector, the Lamprey Lock, demonstrated higher flow rates than those demonstrated by a conventional Luer connector in vitro.

Endovascular salvage of thrombosed haemodialysis vascular access

Background: Haemodialysis access thrombosis is associated with significant morbidity and access abandonment rates, for which endovascular salvage is a well described treatment option. This study aimed to evaluate the outcomes of endovascular salvage procedures of thrombosed vascular access circuits and identify factors influencing outcomes. Patients and methods: Retrospective review of 328 consecutive procedures performed over 10 years at our institution between January 2010 and December 2019. Patient demographics, access circuit characteristics, procedure details and outcome data were collected. Kaplan-Meier survival curves were used to estimate patency rates and Cox multivariate regression analysis to identify factors affecting outcomes. Results: Technical and clinical success rates were 87.8% and 75.9% respectively. The primary, primary assisted and secondary patency rates at 6 months were 42.2%, 46.7% and 59.1%; and at 12 months were 23.4%, 28.3% and 41.8% respectively. Median access circuit survival was 9.2 months. Major complication rate was 5.2% including 3 procedure-related deaths. Native AVF, lower time from thrombosis to intervention and pharmacomechanical thrombectomy using AngioJet^TM predicted positive outcomes. Previous thrombectomy within 3 months and residual thrombus at completion were associated with poorer outcomes. Age and hypertension predicted higher complication rates. Conclusions: This is one of the largest single center series of endovascular salvage of thrombosed haemodialysis access and demonstrates that endovascular treatment is effective and provides durable access circuit survival. Careful patient screening is essential to optimize outcomes.

Scoop thrombectomy: A declotting technique for the treatment of thrombosed autologous arteriovenous fistula. A single-center retrospective study

BACKGROUND

Thrombosis is one of the main complications leading to the failure of autologous arteriovenous fistula (AVF) for patients with renal failure. Thrombectomy is one of the major therapies to remove thrombi to salvage the AVF and prolong its patency.

MATERIALS AND METHODS

Fifty-six patients with AVF thrombosis at the anastomosis were recruited for this study and underwent thrombectomy procedures. Their clinical variables were collected. The vasculature was accessed at the site of the aneurysmal dilatation. Under ultrasound guidance, a scoop thrombectomy procedure was performed by anterograde and retrograde scooping to remove the thrombus using forceps. Then, a sheath was placed in the direct vertical direction. Angioplasty was performed with a balloon to treat the underlying primary arteriovenous stenosis. Patients were followed up for 12 months after surgery. The procedural success, primary and secondary patency rates, and incidence of procedure-related complications were analyzed.

RESULTS

There were 2 minor (3.6%) and no major complications. Clinical success was achieved in 55 of the 56 procedures (98.2%). No symptomatic pulmonary embolism or arterial embolization was noted. The primary patency rates at 3, 6, and 12 months were 92.9, 83.8, and 73.3%%, respectively, according to the Kaplan-Meier survival analysis.

CONCLUSION

Scoop thrombectomy is a safe procedure with high technical success and a low complication rate, and it is an effective method for patients to receive hemodialysis immediately.

Association of Frailty With Thrombosis of Hemodialysis Vascular Access: A Prospective Taiwanese Cohort Study

RATIONALE & OBJECTIVE

Frailty, a multidimensional construct, has been associated with poor outcomes in patients receiving maintenance dialysis. This study assessed the association of frailty with dialysis vascular access patency.

STUDY DESIGN

Multicenter prospective cohort study.

SETTING & PARTICIPANTS

761 prevalent patients receiving hemodialysis at 9 centers in Taiwan as of January 2018.

EXPOSURE

Performance-based frailty was defined as 3 of the following: unintentional weight loss, weakness, exhaustion, low physical activity, and slow gait speed. Patients were categorized as prefrail if they had 1 or 2 of these characteristics.

OUTCOME

Rate of and time to dialysis access thrombosis. Data regarding vascular access events were collected for 30 months after enrollment through December 31, 2020.

ANALYTICAL APPROACH

Logistic regression analysis was used to estimate the association of clinical characteristics with frailty. Cox proportional hazards regression analysis was used to estimate the association of frailty with vascular access thrombosis adjusted for known clinical risk factors.

RESULTS

The patients' mean age was 66 years, 46% were female, 18% had synthetic graft accesses, and 82% arteriovenous fistulas. Overall, 31% were frail, 35% were prefrail, and 34% were not frail. The frailty phenotype was associated with age, female sex, low body mass index, diabetes mellitus, and prior stroke. During a median follow-up of 731 days, 161 patients (21%) had access thrombosis events (not frail, 14%; prefrail, 20%; frail, 30%; P < 0.001). Frail patients had a higher risk of vascular access thrombosis than nonfrail patients (HR, 2.31 [95% CI, 1.55-3.39], P < 0.001). After multivariable adjustment for age and comorbidities, frailty remained significantly associated with access thrombosis for both fistulas and grafts.

LIMITATIONS

Limited generalizability and potential residual confounding.

CONCLUSIONS

Frailty is associated with an increased risk of vascular access thrombosis. These findings highlight the risks of access failure experienced by frail patients receiving hemodialysis.

Accessory Vein Obliteration and Balloon-Assisted Maturation for Immature Arteriovenous Fistulas for Haemodialysis: A Systematic Review and Meta-Analysis

PURPOSE

This study aims to examine outcomes of immature arteriovenous fistula salvage using balloon angioplasty (PTA) without and with accessory vein obliteration (PTA + VO).

MATERIALS AND METHODS

PubMed and Embase were accessed on 21 September 2020 to retrieve cohort studies on adult patients with end-stage renal failure (ESRF) requiring dialysis. Risk of bias was assessed using Newcastle-Ottawa Scale. Studies were pooled into PTA or PTA + VO arms, with outcomes (technical/clinical success, primary/secondary post-intervention patency until 12 months) reported as event rates with 95% confidence intervals. Random-effects model and maximum likelihood meta-regression were used for meta-analysis.

RESULTS

Fourteen studies (1030 participants) were included. The between-subgroup difference in outcomes was largely non-significant (p > 0.050).

CONCLUSION

The evidence does not support balloon angioplasty with concomitant accessory vein obliteration for immature fistula salvage.

Cost-Effectiveness of Drug-Coated Balloon Angioplasty Compared With Conventional Balloon Angioplasty for Arteriovenous Access Flow Dysfunction

OBJECTIVES

This study aimed to determine the cost-effectiveness of drug-coated balloon (DCB) angioplasty compared with conventional balloon angioplasty (cPTA) in patients with arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) dysfunction from a Singapore healthcare perspective.

METHODS

Existing cost-effectiveness studies comparing DCB and cPTA have not incorporated AVF/AVG abandonment costs. This Markov model-based economic evaluation incorporated AVF/AVG creation and maturation costs on top of routine intervention costs to model a hypothetical cohort of 60-year-old AVF/AVG flow dysfunction patients. Effectiveness was measured in quality-adjusted life-years. Cost-effectiveness was assessed using incremental net monetary benefit (NMB) at a Singapore willingness-to-pay threshold of Singapore dollar (S$)87 000. Deterministic and probabilistic sensitivity analyses were performed to examine parameter uncertainty. To test hypotheses regarding cost-effectiveness, intervention counts per patient, cumulative incidence functions of AVF/AVG abandonment, and survival curves of death were compared between DCB and cPTA.

RESULTS

DCB was not cost-effective at 3-year horizon (NMB = -S$1424), but was cost-effective at 1- and 6-year horizons (NMB = S$356 and S$3738, respectively). At 3 years, there was a 34.5% probability of DCB being cost-effective, but at 1- and 6-year horizons there was, respectively, 58.6% and 59.9% probability of DCB being cost-effective. DCB had graphically less AVF/AVG-abandonments, but this was not statistically significant (P = .21). Differences in other parameters were neither graphically nor statistically significant.

CONCLUSIONS

With AVF/AVG abandonment considered, DCB may be weakly cost-effective compared with cPTA in treating AVF/AVG flow dysfunction. AV access creation and maturation costs could have important explanatory value in assessing DCB cost-effectiveness.

Long Term Results from The Pivotal Multicenter Trial of Ultrasound Guided Percutaneous Arteriovenous Fistula Creation for Hemodialysis Access

PURPOSE

To report the five-year results from the Pivotal Multicenter Trial of Ultrasound Guided Percutaneous Arteriovenous Fistula (pAVF) Creation for Hemodialysis Access.

MATERIALS AND METHODS

Retrospective review of 107 intent-to-treat (ITT) patients from the pivotal trial provided a long-term follow-up population (LTP) of 85 patients followed a median 50 months (range 12-60). Data evaluated in the LTP group were fistula maturation and use, secondary procedures, and complications. Kaplan-Meier analysis of primary, primary assisted, cumulative patency, and functional patency (time from two-needle to abandonment) were performed for the ITT population.

RESULTS

In the LTP 99% (84/85) of fistulas were mature with 99% (78/79) of patients requiring hemodialysis using their pAVF. Sustained fistula use (two-needle cannulation at prescribed rate, 2/3 sessions) was achieved in 92% (78/85) of patients, with seven patients never using their pAVF because not on dialysis (n=4), peritoneal dialysis (n=2), and refusing to use fistula (n=1). Fistula maintenance was required in 31.8% (27/85) of patients and included fistula dysfunction (21.2%), thrombosis (5.9%), cannulation injury (12.9%), and arm swelling (4.7%). The number of procedures performed per patient per year (PPPY) to maintain function and patency was 0.32 (91/288) for years 2-5. The cumulative patency was 89.5%, 88.4%, 88.4%, 85.6%, and 82.0% years 1-5, respectively. The functional patency was 91.8% at the end of the study. There were no major complications related to pAVF during long-term follow-up CONCLUSION: Percutaneous fistulae have provided clinically effective and durable access for hemodialysis with low complications. Continued use and evaluation of pAVF is warranted.

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

BACKGROUND

Only a few issues of the related factors to hemodialysis access dysfunction have been evaluated, and the effects of antiplatelets to improve the patency of hemodialysis access remained controversial. Hence, this study aimed to determine the related factors to the re-thrombosis of arteriovenous grafts (AVGs) after endovascular treatment.

METHODS

This retrospective study was conducted at a university-affiliated teaching hospital in Southern Thailand. All patients who underwent hemodialysis with thrombosed AVG, who had pharmacomechanical thrombolysis from January 2016 to December 2018, were enrolled. Post-intervention primary patency was analyzed by the Kaplan-Meier method, and the related factors to the re-thrombosis of AVG were evaluated using logistic regression.

RESULTS

A total of 157 patients with thrombosed hemodialysis AVG were enrolled. The most common graft location and configuration was a forearm loop graft (65%). Post-intervention primary patency rate at 1, 3, and 6 months were 79.0%, 67.1%, and 54.0%, respectively. Diabetes mellitus (DM) was a significant related factor for re-thrombosis (hazard ratio [HR], 1.89; 95% confidence interval [CI], 1.20-2.98; p = 0.006). A single antiplatelet after the procedure was a protective factor for re-thrombosis (HR, 0.58; 95% CI, 0.38-0.89; p = 0.013). The median post-intervention primary patency was 15.7 months in the group of single antiplatelet usage, which was better than that of the non-antiplatelet group (p = 0.012).

CONCLUSION

DM and antiplatelet usage were significant related factors to the re-thrombosis of hemodialysis AVG after endovascular salvage.

Hemodialysis Arteriovenous Fistula Dysfunction: Retrospective Comparison of Post-thrombotic Percutaneous Endovascular Interventions with Pre-emptive Angioplasty

OBJECTIVES

We aimed to compare the clinical outcomes of pre-emptive angioplasty versus post-thrombotic percutaneous endovascular restoration of dysfunctional arteriovenous fistula (AVF).

METHODS

This retrospective study reviewed data from 80 patients who underwent 114 endovascular interventions for a malfunctioning AVF from July 2016 to August 2019. Stenotic AVFs were treated with pre-emptive angioplasty. Thrombosed AVFs were treated with percutaneous pharmacomechanical fibrinolysis with urokinase used only during the operation or continuously infused. The differences in patency rates were evaluated using Kaplan-Meier method. In addition, univariate and multivariate regression Cox models were used to determine influential factors on the post-intervention primary patency.

RESULTS

Post-thrombotic interventions and pre-emptive angioplasty yielded statistically similar rates in clinical success (100% vs 100%), anatomic success (94% vs 89%; p = .52), complication (4% vs 11%; p = .29), as well as postintervention primary, assisted primary and secondary patency (p = .80; .57; .57). The use of pre-emptive angioplasty was associated with reduced total cost (¥25108 vs ¥30833, p< .001). The patients who used urokinase only during the operation prolonged both the primary and assisted primary patency (p = .02; .002), while those with continuous infusion of urokinase had worst patency rates and high costs (¥39275 vs ¥25108 vs ¥27140, p< .001). Compared with the other locations, dysfunction in the anastomotic or juxta-anastomotic segment (HR = .41, p = .001) was associated with prolonged postintervention primary patency.

CONCLUSIONS

No clinical outcome differences was found between the post-thrombotic percutaneous endovascular interventions and pre-emptive angioplasty. However, pre-emptive angioplasty decreased access expenditure.

Stent grafts improved patency of ruptured hemodialysis vascular accesses

This study aimed to compare stent graft with balloon tamponade for ruptured dialysis access during percutaneous transluminal angioplasty. Patients over an 8-year period (2010–2018) were identified from a database of 11,609 procedures. The primary endpoint was target lesion primary patency at 12 months. A total of 143 patients who had rupture dialysis access were enrolled, of whom 52 were salvaged by stent grafts and 91 were salvaged by balloon tamponade. The 6-month target lesion primary patency was greater in the stent graft group than in the balloon tamponade group (66.7% vs. 29.5%, P < 0.001). The benefit of stent grafts was sustained for 12 months (52.5% vs. 9.0%, P < 0.001). The stent grafts increased the median time from the index procedure to the next intervention in the ruptured area by 171 days (260 vs. 89 days) at 12 months. There was no significant difference in the access circuit patency rates at 6 months (25.5% vs. 19.8%, P = 0.203) and 12 months (12.0% vs. 5.8%, P = 0.052). The patency results of the stent grafts remained after the multivariable adjustment analysis. Compared to balloon tamponade alone, stent grafts provided superior target lesion primary patency at 6 and 12 months. The access circuit patency rates were similar.

Role of Endovascular Treatment in Dysfunctional Hemodialysis Fistulae: A Single Center Experience

Introduction

Arteriovenous fistulas (AVFs) are the preferred route of hemodialysis in end-stage renal disease. However, recurrent patency loss is an obstacle in long-term maintenance. Endovascular treatments may provide a durable option for prolongation of patency in AVFs.

Methods

Retrospective observational study was done on 46 patients with AVF for hemodialysis in the Department of Diagnostic and Interventional Radiology for a period of 1 year from September 2020 to August 2021. The characters of dysfunctional fistulas and results of various interventional procedures were assessed for technical and clinical success rates. Short-term follow-up records of patients were assessed for post-intervention primary patency (PIPP) and post-intervention assisted primary patency (PIAPP) of various procedures.

Results

The most successful outcomes post intervention were seen in radio-cephalic fistulas formed more than 1 year ago with juxta-anastomotic narrowing. The overall technical success rate was 89.13% with a PIPP of 78.26% and a PIAPP of 82.60% at 3 months. PTA had better technical success rates (88.23%) as compared to dysfunctional segments with thrombosis that underwent angioplasty and thromboaspiration (84.2%). Central venous stenosis undergoing PTA and stenting had a 100% success rate. At 3 months follow-up, PIPP was better among the angioplasty plus thromboaspiration group (73.7%), while PIAPP rate was better in the angioplasty subgroup at 82.35%.

Conclusion

Endovascular intervention is the first-line treatment in dysfunctional AVFs attributable to the multitude of options available, all of which have comparable outcomes, high success rates, and notable short-term patency.

VOLume flow assistance for optimizing outcomes of dysfunctional autologous arteriovenous fistula Angioplasty: the VOLA Pilot Study

OBJECTIVES

To investigate the feasibility of VF-assisted angioplasty (VFA) in dysfunctional AVF using sequential intraprocedural duplex ultrasound (DUS), to utilize intraprocedural VF as a quantifiable, functional endpoint in endovascular treatment.

METHODS

This prospective study included 20 consecutive patients (23 lesions; 16 men; mean age 67 ± 16 years) with dysfunctional AVF undergoing fluoroscopically guided balloon angioplasty between June 2019 and May 2020. Primary endpoints were quantification of outcome using sequential DUS VF analysis following each dilation, 6-month target lesion re-intervention (TLR)-free rate, standard technical success, procedural success (achievement of a postprocedural VF value equal (or 10% less) or superior to the baseline steady-state access), and correlation between procedural success and TLR-free rate. Secondary endpoints included 6-month lesion late lumen loss (LLL), correlation between balloon diameter used and intraprocedural VF values, and correlation between VF and LLL at 6 months follow-up.

RESULTS

Mean VF increase was 168.5% ± 102.5% (range: 24.24-493.33%). Procedural success was 80% (16/20 cases). VFA improved procedural success by 20% (4/20 cases) compared to standard assessment (< 30% residual stenosis and palpable thrill). TLR-free rate was 78.3% and 67.3% at 6 and 12 months. Significantly less TLR was noted in cases of procedural success (82.4% vs. 66.7% 6 months; p = 0.041). Unweighted linear regression showed a significant positive relationship between diameter of balloon and VF (146.9 ± 42.3 mL/min VF gain per mm of balloon diameter; p = 0.001, R2 = 0.23) and a significant negative relationship between LLL and VF decline at follow-up (102.0 ± 34.6 mL/min loss per mm of LLL; p = 0.01, R2 = 0.35). Optimal VF cutoff value and percentile increase to predict access failure were 720 mL/min (sensitivity 58.3%, specificity 71.4%) and 153% (sensitivity 66.7%, specificity 85.7%), respectively.

CONCLUSION

Intraprocedural VF assessment could be used to optimize AVF angioplasty.

KEY POINTS

• A newly proposed functional endpoint of angioplasty in dysfunctional dialysis fistula was evaluated and angioplasty outcome was quantified using volume flow (VF) assessment with sequential intraprocedural DUS. • Intraprocedural VF assessment improved immediate procedural success; increased balloon diameter was correlated with VF gain and late lumen loss with VF decline. • Intraprocedural VF values ≥ to baseline steady-state values were correlated with less re-interventions.

Modified lyse and wait technique for the treatment of dialysis fistula thrombosis: Percutaneous thrombolytic therapy with a 27-G dental needle

BACKGROUND

The lyse and wait technique is a percutaneous endovascular technique in the treatment of thrombosed dialysis fistulas. In this study, our aim was to introduce a more easily applicable modification of the lyse and wait technique and present our results.

METHODS

A total of 84 patients (56 male; 66.6%), with a mean age of 61 years, were included in the study. The treatment was performed in patients presenting with dialysis fistula thrombosis no more than 1 week before the procedure, whose thrombosed segment length was less than 10 cm. A 27-G dental needle was inserted into the thrombosed segment under ultrasonography guidance, and 5 mg of alteplase was injected in a controlled manner. After about 6 to 12 h, the patients were taken to the angiography unit, and balloon angioplasty was performed.

RESULTS

The technical and clinical success of the procedure was 98.8%. Technical and clinical failure occurred in only one patient. The median primary patency duration was 13.5 months. None of the patients had major complications. At the end of 12 months, the primary patency rate was 66.6%, and the secondary patency rate was 80%.

CONCLUSIONS

Our technique has shown to have high technical and clinical success and patency.

Ultrasound-guided nitinol stent implantation in treatment of early recurrent stenosis of arteriovenous fistula

To investigate the feasibility, methods and efficacy of ultrasound-guided nitinol stent implantation for the treatment of early recurrent stenosis of arteriovenous fistula (AVF). Thirty patients with early recurrent stenosis after percutaneous transluminal angioplasty (PTA) who received ultrasound-guided nitinol stent implantation in Sir Run Run Shaw Hospital of Zhejiang University from April 2018 to July 2020 were followed up. The imaging features of the procedure and the interventional devices were observed under ultrasonography. The technical success rate and the clinical success rate as well as the incidence of complication were assessed. The post-interventional primary patency rates of access circuit, primary patency rates of target lesion and secondary patency rates were estimated. Ultrasonography was able to demonstrate the operation process and the interventional devices clearly. The technical and clinical success rates were both 100.0%. Eight patients had in-stent restenosis, which were treated by PTA. The post-interventional primary patency rates of the access circuit after 3, 6, 9 and were 91.3%, 86.2%, 86.2% and 64.2%, respectively; the post-interventional primary patency rates of target lesion were 100.0%, 100.0%, 86.4% and 69.3%, respectively; the post-interventional secondary patency rates were 100.0%, 100.0%, 100.0% and 94.4%, respectively. Compared with previous PTA in these cases, stent implantation had a higher post-interventional primary patency rates of target lesion and a lower cost-effectiveness (both <0.05). No other complications such as vascular rupture, pseudohemangioma, stent infection, stent displacement and stent exposure were observed during the follow-up. Ultrasonography can accurately guide the nitinol stent implantation in AVF, and the technique is feasible in treatment for the early recurrent stenosis after PTA with good short- and medium-term efficacy.

A UK Expert Consensus Approach for Managing Symptomatic Arteriovenous Fistula (AVF) Stenosis in Haemodialysis Patients

PURPOSE

Stenoses in mature arteriovenous fistulas (AVFs) are common and can negatively impact on the quality of haemodialysis, the longevity of the AVF and lead to debilitating symptoms. Multiple treatment options exist; however, management can vary between different centres. We aimed to establish multidisciplinary consensus on the optimal stepwise application of interventions based on evidence and consensus.

METHODS

A modified Delphi process was conducted with 13 participants from hospitals across the UK, all of whom have high-volume dialysis access practice.

RESULTS

The usual intervention to rectify de novo stenoses of mature AVFs is fistuloplasty, although surgery for inflow segment stenoses is also clinically acceptable. Appropriate first-line interventions include plain old balloon angioplasty or high-pressure balloon angioplasty; if these fail during the fistuloplasty, consider upsizing the balloon, prolonged balloon inflation or using alternative interventions, such as cutting or scoring balloons and ultra-high-pressure balloons. Alternative or subsequent interventions vary by anatomical site and may require additional multidisciplinary team input. For a stenoses recurring between 3 and 12 months, it is appropriate to consider interventions used de novo, but with a lower threshold for using drug-coated balloons (DCBs) in all regions and for using stent grafts in all regions but inflow segment. Recurrence after 12 months should be treated as a de novo lesion, with DCBs considered if they have been used successfully during previous interventions.

CONCLUSIONS

These recommendations aim to provide a practical guide to multidisciplinary teams in order to optimise the use of multiple interventions for rectifying AVF stenoses and provide unified evidence-based practice guidelines.

Results of drug-eluting stent in significant restenosis of the hemodialysis access: An initial study

BACKGROUND

This study aimed to report the 12-month results of drug-eluting stent (DES) for the treatment of significant restenosis of the hemodialysis access.

MATERIALS AND METHODS

A total of 14 patients (seven men and seven women; median age 70 years; range of 50-83 years) with significant restenosis of hemodialysis accesses were enrolled from January 2017 to December 2018. A total of 10 arteriovenous graft (AVG) and four arteriovenous fistulae were treated with DES. Study outcomes included primary patency of the target lesion and circuit.

RESULTS

Venous anastomosis of the AVG was the most common target lesion for DES insertion (nine hemodialysis accesses). The range of follow-up time was 12-36 months. Primary patency rates of target lesion before DES (patency for last conventional balloon angioplasty [CBA]) versus target lesion after DES at 6 and 12 months were 29% versus 100% and 7% versus 86% (p < 0.001). Primary patency rates of pre-DES circuit (patency for last CBA) versus post-DES circuit at 6 and 12 months were 29% versus 64% and 7% versus 29%, respectively (p = 0.058).

CONCLUSION

DES might improve the patency rate of target lesion in patients with significant restenosis of the hemodialysis access.

Paclitaxel-Coated Balloons for the Treatment of Symptomatic Central Venous Stenosis in Vascular Access: Results From a European, Multicenter, Single-Arm Retrospective Analysis

INTRODUCTION

This was a European, multicenter, investigator-initiated and run, single-arm retrospective analysis to assess the safety and the clinical benefit of the use of paclitaxel-coated balloon (PCB) for the treatment of symptomatic central venous stenosis (CVS).

MATERIALS AND METHODS

Eleven centers from 7 countries across Europe, submitted 86 cases performed during the period between October 2015 and June 2018. Minimum follow-up was 6 months. Patient baseline demographics and procedural details were collected. Mean age was 62.6 years (SD 15.2 years). Median vascular access age was 3.0 years (IQR 1.2-4.8 years). A total of 55 were arteriovenous fistulas (64%) the rest arteriovenous grafts (31/86, 36%). Vessels treated were 43 subclavian veins, 42 brachiocephalic veins and 1 superior vena cava. Median drug-coated balloon diameter was 10 mm (IQR 8-12 mm). Primary outcome measures were clinically assessed intervention-free period (IFP) of the treated segment at 6 months and procedure-related minor and major complications. Secondary outcome measures included access circuit survival, patient survival, and the investigation of independent factors that influence the IFP.

RESULTS

IFP was 62.7% at 6 months. Median patient follow-up time was 1.0 year (IQR 0.5-2.2 years). There was 1 minor complication (1/86; 1.2%) and no major complications. Access circuit survival was 87.7% at 6 months. Patient survival was 79.7% at 2 years according to Kaplan-Meier survival analysis. Higher balloon diameters significantly favored IFP [HR 0.71 (0.55-0.92), p=0.006; 5-7 mm group vs 8-12 mm group, p=0.025].

CONCLUSION

In this analysis, use of PCBs for the treatment of symptomatic CVS was safe. Efficacy was comparable to previous trials. Increased balloon size had a significant effect on patency rates.

Adherence to the RIGHT statement in Society of Interventional Radiology guidelines

Context

The Reporting Items for Practice Guidelines in Health Care (RIGHT) Statement was developed by a multidisciplinary team of experts to improve reporting quality and transparency in clinical practice guideline development.

Objective

To assess the quality of reporting in clinical practice guidelines put forth by the Society of Interventional Radiology (SIR) and their adherence to the RIGHT statement checklist.

Methods

In March 2018, using the 22 criteria listed in the RIGHT statement, two researchers independently documented adherence to each item for all eligible guidelines listed by the SIR by reading through each guideline and using the RIGHT statement elaboration and explanation document as a guide to determine if each item was appropriately addressed as listed in the checklist. To qualify for inclusion in this study, each guideline must have met the strict definition for a clinical practice guideline as set forth by the National Institute of Health and the Institute of Medicine, meaning they were informed by a systematic review of evidence and intended to direct patient care and physician decisions. Guidelines were excluded if they were identified as consensus statements, position statements, reporting standards, and training standards or guidelines. After exclusion criteria were applied, the two researchers scored each of the remaining clinical practice guidelines (CPGs) using a prespecified abstraction Google form that reflected the RIGHT statement checklist (22 criteria; 35 items inclusive of subset questions). Each item on the abstraction form consisted of a “yes/no” option; each item on the RIGHT checklist was recorded as “yes” if it was included in the guideline and “no” if it was not. Each checklist item was weighed equally. Partial adherence to checklist items was recorded as “no.” Data were extracted into Microsoft Excel (Microsoft Corporation) for statistical analysis.

Results

The initial search results yielded 129 CPGs in the following areas: 13 of the guidelines were in the field of interventional oncology; 16 in neurovascular disorders; five in nonvascular interventions; four in pediatrics; 25 in peripheral, arterial, and aortic disease; one in cardiac; one in portal and mesenteric vascular disease; 37 in practice development and safety; three in spine and musculoskeletal disorders; 14 in venous disease; five in renal failure/hemodialysis; and five in women’s health. Of the 46 guidelines deemed eligible for evaluation by the RIGHT checklist, 12 of the checklist items showed less than 25% adherence and 13 showed more than 75% adherence. Of 35 individual RIGHT statement checklist items, adherence was found for a mean (SD) of 22.9 items (16.3). The median number of items with adherence was 21 (interquartile range, 7.5–38).

Conclusion

The quality of reporting in interventional radiology guidelines is lacking in several key areas, including whether patient preferences were considered, whether costs and resources were considered, the strength of the recommendations, and the certainty of the body of evidence. Poor adherence to the RIGHT statement checklist in these guidelines reveals many areas for improvement in guideline reporting.

Single-Center Prospective Pilot Study of Sirolimus Drug-Coated Balloon Angioplasty in Maintaining the Patency of Thrombosed Arteriovenous Graft

PURPOSE

To investigate the use of a sirolimus drug-coated balloon (DCB) in the management of a thrombosed arteriovenous graft (AVG).

MATERIALS AND METHODS

A single-center prospective pilot study was conducted between October 2018 and October 2019. Twenty patients (age = 67.0 years ± 10; male = 35%; mean time on dialysis = 31 months) with thrombosed upper limb AVG were enrolled. After successful pharmacomechanical thrombectomy and adequate treatment of the graft vein junction, sirolimus DCB angioplasty was performed at the graft vein junction. The patients were followed-up for 6 months, and all adverse events occurring during the study period were recorded.

RESULTS

The primary circuit patency rates at 3 and 6 months were 76% and 65%, respectively, while the assisted-primary circuit patency rates at 3 and 6 months were 82% and 65%, respectively. The 3- and 6-month secondary circuit patency rates were 88% and 76%, respectively. Using Kaplan-Meier analyses, the estimated mean primary, assisted-primary, and secondary patencies were 285 days (95% confidence interval (CI) = 194-376 days), 319 days (95% CI = 221-416 days), and 409 days (95% CI = 333-485 days). No adverse event directly related to sirolimus DCB use was observed.

CONCLUSIONS

The results of this pilot study suggest that the application of sirolimus DCB at the graft vein junction after the successful thrombectomy of AVG may be a feasible option to improve patency outcomes.

Use of the Viabahn covered stent for the treatment of venous rupture during interventions of dysfunctional or thrombosed hemodialysis vascular access

BACKGROUND

Angioplasty-related vessel rupture is a common complication of interventions. The effect of covered stents to treat venous rupture has been evaluated in smaller series, but should be further evaluated.

OBJECTIVE

To report the immediate outcomes and patency rates of a covered stent to rescue angioplasty-related venous rupture of hemodialysis vascular access.

METHODS

From January 2013 to December 2018, 113 procedures complicated with vessel ruptures were retrospectively analyzed from a prospectively collected database of 8146 hemodialysis access interventions. The strategies to salvage vessel ruptures were based on the discretion of the treating physicians. Follow-up outcomes were obtained via review of the angiographic images, procedural notes, and medical and dialysis records within 12 months after the index procedures.

RESULTS

A total of 52 vessel ruptures (21 fistulas, 31 grafts) salvaged by using Viabahn covered stents were enrolled. Vessel ruptures developed in 28 (53.8%) thrombectomy procedures. Device success was achieved in all procedures (100%) and clinical success was achieved in 50 (96.2%). The primary patency of the stent area was 66.0% at 6 months and 50.0% at 12 months. The primary patency of the entire access circuit was 27.4% at 6 months and 16.0% at 12 months. The most common cause of access circuit primary patency loss was thrombotic occlusion for graft accesses and restenosis at stent area for native accesses. Eleven vascular accesses were abandoned within 12 months after vessel ruptures, and the secondary patency rate of the entire access circuit was 78.0% at 12 months.

CONCLUSIONS

Treatment of angioplasty-induced vessel rupture of hemodialysis vascular accesses by using Viabahn covered stents has good immediate outcomes and patency results at the stent area. Nonetheless, the patency rate of entire access circuit was still below the threshold recommended by guidelines.

Outcome of Percutaneous Intervention in Dysfunctional Loop versus Straight Arteriovenous Grafts in Hemodialysis Patients

Objective:

To compare the patency control of dysfunctioning forearm arteriovenous graft (AVG) using percutaneous transluminal angioplasty (PTA) in patients with loop versus straight grafts.

Materials and Methods:

Between January 2012 and March 2017, hemodialysis patients with forearm AVG were treated with PTA at two hospitals. We reviewed technical and clinical success rates of each procedure. Procedure time and patency of the graft were compared for all patients as well as for subgroups of stenosis only and thrombosis using paired-sample t-test and Kaplan-Meier analysis.

Results:

Sixty-six patients (mean age, 62.11 ± 11.85 years) underwent PTA. Thirty-eight patients (58%) had loop grafts and 28 (42%) had straight grafts. Among 66 patients, 54 (82%) had thrombosis. Technical success rate was 95.5% (only stenosis: 100%; thrombosis: 94%) and the mean procedure time was 48.00 ± 16.75 minutes in all patients. Although there was a tendency towards shorter procedure time in patients with loop grafts (45.24 ± 20.24 minutes) than those with straight grafts (51.85 ± 22.76 minutes), the difference was not statistically significant (p = 0.217), with or without thrombi. There was no statistical significance in primary and assisted primary patency (log rank 0.78, p = 0.38 in primary patency; log rank 0.88, p = 0.35 in assisted primary patency).

Conclusion:

Our study suggests there is no different patency outcome between straight and loop arteriovenous grafts after PTA.

Study protocol of a pilot study on sirolimus-coated balloon angioplasty in salvaging clotted arteriovenous graft

Background

In arteriovenous graft (AVG) for haemodialysis, the primary cause of failure is venous stenosis of the graft-vein junction from neointimal hyperplasia (NIH), resulting in thrombosis. While interventions to salvage clotted AVG are known to have high clinical success rates, long-term patency rates have been suboptimal. Drug-coated balloon (DCB) has been used to treat stenosed arteriovenous access in recent years with encouraging results but data on its effect in clotted AVG is unavailable.

Methods

This is an investigator-initiated, single-center, single-arm prospective pilot study to determine the safety and outcome of the sirolimus-coated balloon (SCB) in the salvage of thrombosed AVG. Twenty patients who undergo successful percutaneous thrombectomy will receive treatment with SCB at the graft vein junction. The patients will be followed-up for 6-months. The primary endpoint is the patency rates at 3-month while the secondary endpoints are the patency rates and the number of interventions needed to maintain patency at 6-month.

Discussion

Unremitting efforts have been made to prolong the patency of AV accesses over the years. DCB angioplasty combines mechanical and biological treatment for vascular stenosis. Sirolimus, being a cystostatic anti-proliferative agent, has been successfully used in coronary artery interventions. As the primary pathology of vascular stenosis in the dialysis circuit is neointimal hyperplasia, the use of sirolimus in balloon angioplasty may be effective. With this prospective study, we evaluate the efficacy and safety of SCB in patients with clotted AVG.

Trial registration

ClinicalTrials.gov Identifier: NCT03666208 on 11 September 2018.

Diagnosis and Treatment of Nonmaturing Fistulae for Hemodialysis Access via Transradial Approach: A Case-Control Study

PURPOSE

To compare outcomes of transradial access for endovascular treatment of nonmaturing hemodialysis fistulae compared to brachial arteriography followed by unidirectional or bidirectional fistula access for intervention.

MATERIALS AND METHODS

In this institutional review board-approved, retrospective, case-control study, 56 consecutive patients with nonmaturing arteriovenous fistulae underwent percutaneous intervention between 2015 and 2018. The transradial group (n = 28) underwent radial artery access for diagnostic fistulography and intervention. The control group (n = 28) underwent retrograde brachial artery access for fistulography followed by unidirectional/bidirectional fistula access for intervention. Both groups had similar demographics, fistula characteristics, and stenosis locations.

RESULTS

Fewer punctures were required in the transradial group compared to controls (1.2 vs 2.4, P < .0001), and procedure time was shorter (64.9 vs 91.3 minutes, P = .0016). Anatomic, technical, and clinical success rates trended higher in the transradial group compared to controls (93% vs 86%, 96% vs 89%, and 82% vs 64%, respectively). Nonmaturation resulting in fistula abandonment was lower in the transradial group (3.7% vs 25%, P = .025). Primary unassisted patency at 3, 6, and 12 months was 77.1% ± 8.2%, 73.1% ± 8.7%, and 53.3% ± 10.6% in the transradial group, respectively, and 63.0% ± 9.3%, 55.6% ± 9.6%, and 48.1% ± 9.6% in the control group, respectively (P = .76). Primary assisted patency at 12 months was 92.3% ± 5.3% in the transradial group compared to 61.8% ± 9.6% at 12 months in the control group (P = .021). No major complications occurred. Minor complications were lower in the transradial group than in the control group (14% vs 39%, P = .068).

CONCLUSIONS

Treatment of nonmaturing fistulae via a transradial approach was safe, improved midterm patency, and was associated with lower rates of fistula abandonment.

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

Background

Restenosis remains a significant problem in endovascular therapy for hemodialysis vascular access. Drug-coated balloon (DCB) angioplasty decreases restenosis in peripheral and coronary artery diseases. The aim of this systematic review and meta-analysis is to assess the patency outcomes following DCB angioplasty, as compared to conventional balloon (CB) angioplasty for the stenosis of hemodialysis vascular access.

Methods

A comprehensive search in the MEDLINE, EMBASE, and CENTRAL databases was conducted in order to identify eligible randomized controlled trials evaluating DCB angioplasty for hemodialysis vascular access dysfunction. The primary endpoint was the 6-month target lesion primary patency and the secondary endpoints were 12-month target lesion primary patency and procedure-related complications. Risk ratios (RR) were pooled and relevant subgroups were analyzed separately.

Results

Eleven randomized controlled trials comprised of 487 patients treated with DCB angioplasty and 489 patients treated with CB angioplasty were included. There were no significant differences in the target lesion primary patency at 6 months [RR, 0.75; 95% confidence interval (CI), 0.56, 1.01; p = 0.06] and at 12 months (RR 0.89; 95% CI, 0.79, 1.00; p = 0.06). The absence of benefit for the DCB group remained, even in the arteriovenous fistula subgroup or the subgroup of studies excluding central vein stenosis. The risk of procedure-related complication did not differ between the two groups (RR 1.00; 95% CI 0.98, 1.02; p = 0.95).

Conclusion

DCB angioplasty did not demonstrate significant patency benefit for the treatment of hemodialysis vascular access dysfunction. Wide variations in patency outcomes across studies were noted. Further studies focusing on specific types of access or lesions are warranted to clarify the value of DCB for hemodialysis vascular access. (PROSPERO Number CRD42019119938)

Use of the Covera Stent Graft for the Treatment of Dysfunctional or Thrombosed Arteriovenous Grafts: A Retrospective Analysis of 64 Patients

PURPOSE

To retrospectively evaluate the safety and effectiveness of the Covera stent graft (SG) for the treatment of dysfunctional or thrombosed arteriovenous grafts (AVGs).

MATERIALS AND METHODS

Within 29 months (February 2016-August 2018), 79 patients underwent Covera SG placement in the authors' department for the treatment of dysfunctional AVGs. Data were available for 64 patients who underwent 64 procedures, using 64 devices. Minimum follow-up was 6 months, unless reintervention occurred. Mean follow-up was 277 days (6-923 days). Treatment characteristics were 51 cases with venous-graft anastomosis (VGA) stenosis (79.7%), 13 cases of puncture zone stenosis (20.3%), 14 cases of in SG stenosis (21.9%), 8 cases of pseudoaneurysm treatment (12.5%) (1 treatment area might have had more than 1 characteristic). Thirty-six patients presented with thrombosis (56.2%), and 31 of 64 case were de novo treatment areas (48.4%). Primary outcome measurements were technical success and post-intervention primary patency (PIPP) at 6 months, whereas secondary outcome measurements included factors influencing primary outcome.

RESULTS

Technical success was 100%. Median PIPP was 336 days, and 73.6% of treatment areas were patent at 6 months. There were no significant differences in terms of PIPP when de novo treatment areas were compared with restenotic areas (519 vs. 320 days, respectively; P = .1); patients who presented with versus those who presented without thrombosis (320 vs. 583 days, respectively; P = .07); puncture zone stenosis or elsewhere (329 vs. 686 days, respectively; P = .52); and VGA stenosis or elsewhere (336 vs. 335 days, respectively; P = .9).

CONCLUSIONS

Use of the Covera SG for AVG treatment was safe and effective in every type of treatment area presented in this retrospective analysis.

Factors influencing outcomes of rheolytic thrombectomy on thrombosed dialysis access grafts: Door to angiographic bed time and what else?

BACKGROUND

The aim of this study was to investigate the effect of the time interval from clinical presentation of arteriovenous graft thrombosis and the thrombectomy procedure by the AngioJet system in terms of technical and clinical success and to identify factors influencing success.

METHODS

A total of 60 consecutive patients (35 men and 25 women; mean age = 52 ± 7.89 years) who had undergone percutaneous thrombectomy by the AngioJet device from 2016 to 2019 were retrospectively enrolled. Demographics and fistula data, previous treatments, time from clinical onset of thrombosis to intervention, procedural details and complications were recorded. Technical and clinical success and primary and secondary patency rates were calculated. One-way analysis of variance was performed to test any correlation between patient-related and fistula/procedure-related variables and technical/clinical success. Odds ratio and relative risk were also calculated when necessary.

RESULTS

Technical success and clinical success were 95% and 91.7%, respectively. Post-interventional primary and secondary patency rates at 1 year were 72.5% and 84.3%, respectively. Complication rate was 6.7%. One-way analysis of variance showed that clinical success was higher in patients with no previous treatment (p = 0.015). Furthermore, clinical success was significantly associated with door to angiographic bed time (p = 0.002): p-value for the 24-h and the 72-h cut-off was 0.012 and 0.006, respectively.

CONCLUSION

Percutaneous rheolytic thrombectomy is safe and effective for thrombosed arteriovenous grafts, with acceptable primary and secondary patency rates. Higher clinical success was found in patients never treated before and when the procedure was carried out within 24 h from the clinical onset of thrombosis.

Stent graft deployment in haemodialysis fistula: patency rates in partially thrombosed aneurysm and residual thrombi

Background

Current evidence is insufficient to determine the contribution of stent grafts as treatment in partially thrombosed aneurysms or residual wall-adherent thrombi in arteriovenous fistulae (AVFs) for haemodialysis. The overall purpose of this study was to analyse patency rates of post-interventional covered stent deployment in those cases. We also assessed if patency rates differed when fistulas were punctured through the stent during dialysis sessions.

Methods

We conducted a retrospective study between 2006 and 2014 analysing post-intervention primary patency rates using the Kaplan-Meier log-rank test. Multivariate Cox proportional regression models were performed to determine if cannulation within the stent graft area was a potential risk factor for occlusion, by adjusted hazard ratio (HR).

Results

A total of 27 procedures were included in the study. Primary patency rates (%) after stent deployment at 3, 6, 12, 24, 36 and 72 months were, respectively: total 59, 32, 32, 21, 11 and 5; stent puncture 53, 21, 21, 16, 5 and 0; and no stent puncture 80, 80, 80, 40, 40 and 40. Cannulation through the stent graft was not significantly associated with increased risk of obstruction in multivariate analysis (HR = 3.01; P = 0.286).

Conclusion

Stent graft treatment may be a feasible procedure in partially thrombosed aneurysms and residual thrombi in AVF. Although fistulas punctured through the stent presented lower patency rates, this practice was not associated with a higher risk of obstruction. Giving the impossibility of comparing with similar approaches, further studies are needed to confirm or refute the advantages of this procedure.