Procedural success and patency after percutaneous treatment of thrombosed autogenous arteriovenous dialysis fistulas

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.

Pulmonary embolism in an ESRD patient following minimal venotomy and milking for salvage of dysfunctional autogenous arteriovenous fistula

Pulmonary embolism can be a complication following an attempted salvage of a dysfuctional arteriovenous fistula (AVF). We report a case of bilateral pulmonary embolism in a patient with underlying pericardial effusion who, following minimal venotomy and milking of the AVF, developed sudden and significant respiratory distress, and later improved.

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.

Results of Prompt Surgical Intervention in Hemodialysis Radiocephalic Fistula Secondary Dysfunction

Radiocephalic fistula (RCF) dysfunction is a common problem due to low maturation and patency rates of these fistulas. The most common procedure in such cases is to place a temporary catheter for the dialysis. Temporary catheter placement and undergoing dialysis with this catheter cause complications, reduce the chance for fistula, and deteriorate the quality of life. The aim of this study was to demonstrate that immediate intervention in RCF dysfunctions can increase fistula success for the patient and can reduce the need for a catheter. Furthermore, the hemodialysis treatment can continue without affecting the quality of life. A total of 295 patients who were admitted for RCF dysfunction and who underwent early surgical intervention without any catheter placement were evaluated for postoperative complications, patency rates, and rates and durations of temporary catheter use over a mean time of 47 months of follow-up (range: 4–79 months). Of the patients, 77.2% (n = 228) underwent new proximal anastomosis (NEO; the radial artery and cephalic vein were reached with an incision created proximal to the previous anastomosis), 14.2% (n = 42) underwent brachiocephalic arteriovenous fistula (AVF), 8.4% (n = 25) underwent side-to-side brachiobasilic AVF + superficialization of the basilic vein. In 88.8% (n = 262) of the patients, successful cannulations were performed within the first 24 to 48 hours without any catheter requirement or complications. Temporary catheter was used for 15.1 ± 10.7 days in 11.2% (n = 33) of the patients. In RCF dysfunctions, early surgical interventions performed in the forearm and elbow provide early cannulation and thus decrease the catheter requirement, also prevent the complications of temporary catheters (infection, decreasing the fistula success, vascular injuries, etc.), increase the autogenous fistula success, and allow for the continuation of dialysis without disturbing the quality of life.

Comparison of pharmacomechanical and surgical interventions for thrombosed native arteriovenous fistulas

Background

This study aims to compare success and patency rates of pharmacomechanical thrombectomy versus open surgical thrombectomy for thrombosed native arteriovenous fistulas.

Methods

A total of 96 patients (56 males, 40 females; mean age 61±11.7 years; range, 26 to 82 years) with a thrombosed native arteriovenous fistula between January 2016 and December 2018 were retrospectively analyzed. The patients were divided into two groups as pharmacomechanical thrombectomy (n=42) and open surgical thrombectomy (n=54). Primary failure rate and primary patency rate at 6 and 12 months were recorded.

Results

Of 42 patients in the pharmacomechanical thrombectomy group, 41 (98%) had additional interventions, and primary failure occurred in four patients (10%). Primary failure was seen in 15 (28%) patients in the surgical group. The primary patency rates at 6 and 12 months were significantly higher in the pharmacomechanical treatment group than the surgical group (85% vs. 67% and 78% vs. 55%, respectively; p<0.05).

Conclusion

Pharmacomechanical thrombectomy procedure yields higher primary patency rates than open surgical thrombectomy for thrombosed native arteriovenous fistula.

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.

Results of the endovascular treatment system for occluded native arteriovenous fistula

BACKGROUND

Arteriovenous fistula is the definitive vascular access for patients on long-term haemodialysis. The aim of this study is to present the techniques and results of the Endovascular Treatment System that we have developed for managing the occluded native arteriovenous fistula.

METHODS

The current study is a retrospective chart review on all patients who presented with an occluded native arteriovenous fistula and underwent attempted recanalization between 1 January 2005 and 31 December 2014.

RESULTS

A total of 130 patients were included in the study. Post-intervention primary access patency was 83.8% at 6 months, 78.7% at 12 months, 64.6% at 2 years and 59.6% at 3 years. Post-intervention assisted access patency in fistulas-in-use was 86.5% at 6 months, 81% at 12 months, 66.8% at 2 years and 61.2% at 3 years. Post-intervention secondary patency for all cases was 84.7% at 6 months, 80.2% at 12 months, 66.1% at 2 years and 62% at 3 years. Post-intervention secondary patency in fistula-in-use was 91.1% at 6 months, 90% at 12 months, 85% at 2 years and 74.6% at 3 years. Access survival nor patency differed significantly when incisional thrombectomy was compared to angioplasty with or without stenting with access survival of 91.2% and 92.5% at 12 months and access patency of 82.9% and 89.7% at 12 months (P = 0.834 and P = 0.898, respectively).

CONCLUSIONS

In autologous arteriovenous thrombosed fistulae, the use of endovascular techniques to revive the access is a viable and safe technique to employ in most cases.

Long-term results of endovascular treatment for arteriovenous dialysis access thrombosis in 143 patients: A single center experience

Objective:

This study aimed to determine the long-term patency duration and rate of thrombosis of autologous arteriovenous fistulas and synthetic grafts treated with endovascular methods in a large patient population.

Methods:

A total of 144 arteriovenous accesses (37 radiocephalic, 51 brachiobasilic, 41 brachiocephalic, and 15 femorofemoral) from 143 patients were included in the study. A total of 304 endovascular thrombolytic treatment procedures were performed for 94 (65%) arteriovenous fistula and 50 (35%) arteriovenous graft accesses.

Results:

The procedural technical success rate was 98.7%. The mean follow-up duration was 32.5 (range, 3–132) months. The primary patency rates for arteriovenous fistulas and arteriovenous grafts were 78% and 78% at 6 months, 66% and 63% at 1 year, and 45% and 0% at 36 months, respectively. The assisted primary patency rates for arteriovenous fistulas and arteriovenous grafts were 82% and 84% at 6 months, 71% and 69% at 1 year, 51% and 29% at 36 months, and 30% and 1% at 60 months, respectively. The secondary patency rates for arteriovenous fistulas and arteriovenous grafts were 94% and 93% at 6 months, 85% and 85% at 1 year, 58% and 59% at 36 months, and 47% and 48% at 60 months, respectively.

Conclusion:

Although the primary patency durations for arteriovenous fistulas were better after endovascular thrombolytic treatment than those for arteriovenous grafts, the long-term outcomes of assisted primary and secondary patency durations after repeated procedures were similar for both types of arteriovenous accesses.

Comparison of alteplase and urokinase for pharmacomechanical thrombolysis of clotted hemodialysis access

BACKGROUND

Percutaneous pharmacomechanical thrombolysis is increasingly used to salvage thrombosed hemodialysis access. We aim to evaluate the effectiveness of alteplase compared to urokinase in percutaneous pharmacomechanical thrombolysis clotted access.

METHODS

Records of patients who underwent pharmacomechanical thrombolysis at Interventional Nephrology Suite in a tertiary teaching hospital from 1 January 2016 to 31 December 2016 were reviewed. Technical and clinical success rates, thrombosis-free and cumulative survivals, procedure time, and radiation dose imparted to patients were compared for pharmacomechanical thrombolysis with urokinase versus alteplase.

RESULTS

A total of 122 incident patients underwent pharmacothrombolysis (n = 53 for urokinase, n = 69 for alteplase) during the study period. The mean dose of urokinase and alteplase used was 176,897 ± 73,418 units and 3.7 ± 0.8 mg, respectively. Pharmacomechnical thrombolysis using urokinase versus alteplase has similar technical success rate (98.1% vs 97.1%, p = 0.599), clinical success rate (88.7% vs 97.1%, p = 0.068), complication rate (9.4% vs 13.0%, p = 0.373), and primary patency rates at 3 months (57.1% vs 70.1%, p = 0.106). Thrombosis-free survivals of the vascular access were 113.2 (35.3, 196) days versus 122 (84, 239) days (p = 0.168). Cumulative survivals were 239 (116, 320) vs 213 (110.5, 316.5) days (p = 0.801). Procedure time, fluoroscopy time, skin dose, and dose were significantly lower for pharmacomechanical thrombolysis using alteplase compared to urokinase (p = 0.045, p < 0.0001, p = 0.006, p = 0.001, respectively). Stenting was found to be associated with successful dialysis following thrombolysis on univariate analysis (odds ratio: 9.167, 95% confidence interval: 1.391-19.846, p = 0.021), although this was no longer significant in multivariate analysis (p = 0.078).

CONCLUSION

Alteplase is an effective and safe alternative to urokinase for pharmacomechanical thrombolysis of clotted vascular access.

MicroRNA-21 and Venous Neointimal Hyperplasia of Dialysis Vascular Access

BACKGROUND AND OBJECTIVES

There is increasing evidence that microRNAs (miRNAs) play crucial roles in the regulation of neointima formation. However, the translational evidence of the role of miRNAs in dialysis vascular access is limited.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

miRNA expression in tissues was assessed by using venous tissues harvested from ten patients on dialysis who received revision or removal surgery, and ten patients who were predialysis and received creation surgery of arteriovenous fistulas served as controls. To extend these findings, 60 patients who received angioplasty of dialysis access were enrolled and the levels of circulating miRNAs were determined before and 2 days after angioplasty. Clinical follow-up was continued monthly for 6 months. The primary outcome of angioplasty cohort was target lesion restenosis within 6 months after angioplasty.

RESULTS

In the surgery cohort, the expressions of miR-21, miR-130a, and miR-221 were upregulated in stenotic tissues, whereas those of miR-133 and miR-145 were downregulated. In situ hybridization revealed similar expression patterns of these miRNAs, localized predominantly in the neointima region. Twenty eight patients in the angioplasty cohort developed restenosis within 6 months. The levels of circulating miR-21, miR-130a, miR-221, miR-133, and miR-145 significantly increased 2 days after angioplasty. Kaplan-Meier plots showed that patients with an increase of miR-21 expression level >0.35 have a higher risk of patency loss (hazard ratio, 4.45; 95% confidence interval, 1.68 to 11.7). In a multivariable analysis, postangioplasty increase of miR-21 expression was independently associated with restenosis (hazard ratio, 1.20; 95% confidence interval, 1.07 to 1.35 per one unit increase of miR-21 expression level; P=0.001).

CONCLUSIONS

Certain miRNAs are differentially expressed in the stenotic venous segments of dialysis accesses. An increase in blood miR-21 level with angioplasty is associated with a higher risk of restenosis.

Haemodialysis access thrombosis: Outcomes after surgical thrombectomy versus catheter-directed thrombolytic infusion

Introduction:

Thrombosis is one of the most common complications of dialysis vascular access and is a significant source of morbidity and healthcare-associated costs. In this retrospective study, outcomes for surgical thrombectomy and thrombolysis after access thrombosis in patients with arteriovenous fistulas or prosthetic grafts (arteriovenous grafts) were analysed.

Methods:

All patients with a primary episode of dialysis access thrombosis between 2005 and 2013 were included which yielded 131 patients with 149 episodes of access thrombosis (108 arteriovenous grafts; 41 arteriovenous fistulas). In all, 18 patients had two separate accesses during the study. Patient demographics, access anatomy, surgical and radiological procedural data were recorded. Kaplan–Meier estimates and Poisson regression were used for statistical analysis of access patency.

Results:

In total, 107 underwent surgical thrombectomy and 42 were treated with catheter-directed thrombolytic infusion. Technical success was 60% for surgical thrombectomy and 73% for thrombolysis (p = 0.18). There were no major complications and no deaths within 30 days of the procedure. More patients had adjunctive procedures in the thrombolysis group (65/107 vs 37/42; p = 0.002). There was an increasing risk of rethrombosis or a further access-related event for both arteriovenous fistulas and arteriovenous grafts after open thrombectomy compared with catheter-directed thrombolytic infusion, and arteriovenous fistulas exhibited a lower risk than arteriovenous grafts with an average increase in risk of 23.9% (95% confidence interval: 3.1–49) between each treatment group.

Conclusion:

Thrombolysis for thrombosis of native and prosthetic dialysis accesses appears to yield better assisted primary patency compared to surgical thrombectomy. Our results suggest that thrombolysis may be considered the first-choice method for treating the thrombosed dialysis access.

Safety and efficacy of the AngioJet device in the treatment of thrombosed arteriovenous fistula and grafts: A systematic review

PURPOSE

The AngioJet Hemolytic Thrombectomy Device "AngioJet" (Boston Scientific, Malborough, MA, USA) is a rheolytic thrombectomy device that can be used in the treatment of hemodialysis arteriovenous fistula and graft thrombosis. We aim to appraise the current evidence on AngioJet thrombectomy in hemodialysis vascular access thrombosis, and to determine its safety, including complications and efficacy.

MATERIALS AND METHODS

An electronic literature search was performed on the MEDLINE and Embase databases. References of retrieved articles were also reviewed. Articles using AngioJet for the treatment of arteriovenous fistula or graft were included. Patients less than 18 years old, non-English articles, single case reports, small case series (<5 cases), conference publications, and nonhuman models were excluded.

RESULTS

A total of 688 articles were initially evaluated and 10 articles fulfilled the inclusion criteria, which included 836 patients with 431 grafts and 234 fistulas. Results were heterogeneously reported. The adjusted mean primary patency rates for 1, 3, 6, and 12 months were 64.6%, 43.8%, 42.5%, and 30.5%, respectively; adjusted mean secondary patency rates for 3, 6, and 12 months were 76.5%, 75.1%, and 74.5%, and assisted primary patency rates were 61.9%, 47.3%, and 35.3%, respectively. There were 126 complications, most were minor. There were seven deaths, but were unable to be attributable to the AngioJet.

CONCLUSION

The AngioJet is an effective and safe treatment option for thrombosed fistulas and grafts. However, the quality of the current evidence is poor. Further research with prospective randomized controlled trials using standardized data reporting methods is needed to prove its safety and efficacy.

Arteriovenous Fistulae vs. Arteriovenous Grafts: A Retrospective Review of 1,700 Consecutive Vascular access Cases

Objective

Vascular access (VA) procedures are rapidly becoming the most prevalent surgery in the United States. It is estimated that there will be over 500,000 VA procedures done this year. Previously, surgeons in the US were attempting many more non-autogenous grafts than autogenous fistulae. In recent years, there has been a great push called “Fistula First” to promote arteriovenous fistulae (AVF) as the first line of treatment vs. non-autogenous grafts. The goal of this investigation is to determine if too many fistulae are now being performed without attention to specific patient profiles.

Methods

A retrospective review of 1700 consecutive cases was performed by one surgeon at one institution between 1997 and 2005. Patients were categorized by demographics, co-morbidities, previous access procedures, access location, and type of graft. Patency was calculated. Kaplan-Meier, Cox regression and the Log Rank Test were used to analyze data. Access endpoints and complications were also documented.

Results

The study reviewed 1700 procedures. The median age was 52 (60.2% male) with 58.7% fistulae and 41.3% grafts. Median patency time was 10 months, with no statistically significant difference between access types. There was no significant difference in length of patency when comparing upper arm (70.1%), lower arm (24.5%) and thigh (5.4%). Graft infection rate was 9.5% and fistula infection rate was 0.9% (p<0.001). The overall infection rate was 4.5%, and decreased patency significantly (4 vs. 11 months). Thrombosis occurred in 24.7% of grafts and 9.0% of fistulae. Thrombosed grafts had better salvage rates (8 vs. 4 months, p<0.001). The data showed diabetes, HTN and HIV have no overall impact on patency.

Conclusions

AVF and grafts are both useful in providing VA for patients requiring hemodialysis. Our data shows that grafts are equivalent in long-term patency. Therefore, it is apparent in those patients who are not candidates for an AV fistula; an AV graft for VA should be placed.

Percutaneous treatment of thrombosed arteriovenous fistulae using the Gelbfish-Endovac aspiration thrombectomy device

Purpose

To study the efficacy and safety of percutaneous treatment of thrombosed hemodialysis arteriovenous fistulae (AVF) using the Gelbfish-Endovac aspiration thrombectomy device (Gelbfish-Endovac).

Methods

From September 2003 to May 2004, twenty-nine percutaneous thrombectomy procedures were performed in 27 patients (median age of 67 years, 14 females) with thrombosed hemodialysis AVF using the Gelbfish-Endovac. Prior interventions, procedure time, anticoagulation, use of additional devices/thrombolytic agents, technical success, clinical success, complication rates, and patency at 30, 60 and 90 days were evaluated.

Results

Sixteen upper arm and 13 forearm AVF were declotted. Seventeen AVF had prior percutaneous interventions. Three AVF had not matured. Median AVF age was 9 months. Heparin was used in 14 procedures. Sixteen arterial lesions and 25 venous lesions were uncovered and treated. Two AVF required the additional use of the Arrow-Trerotola percutaneous thrombectomy device. One AVF underwent side branch ligation. No thrombolytic agents were used. Median procedure time was 70 minutes. Initial technical success was achieved in 24 AVF and clinical success was achieved in 22 AVF. Eleven complications occurred. Ten AVF remained open at 30 days, 10 at 60 days and 8 at 90 days without further interventions. With additional percutaneous interventions, 16 AVF remained open at 30 days, 16 at 60 days and 15 at 90 days.

Conclusion

The Gelbfish-Endovac aspiration thrombectomy device is safe and efficacious for percutaneous de-clotting of AVF.

Timely thrombectomy can improve patency of hemodialysis arteriovenous fistulas

OBJECTIVE

The urgency with which salvage of thrombosed vascular accesses for dialysis should be attempted remains unknown. We examined the effect of a timely thrombectomy approach on vascular access outcomes for dialysis.

METHODS

A before-and-after study was conducted with patients on hemodialysis who had undergone endovascular thrombectomy. A timely thrombectomy initiative (ie, salvage within 24 hours of thrombosis diagnosis) was started in July 2015 at our institution. Data about thrombectomy procedures, performed within 1 year before and after the initiative was introduced, were abstracted from an electronic database. Immediate outcomes and patency outcomes were compared between the preinitiative (control) and postinitiative (intervention) groups.

RESULTS

During the study period, 329 patients were enrolled, including 165 cases before and 164 cases after the initiative. The intervention group had more thrombectomy procedures performed within 24 hours (93% vs 55%; P < .01) and within 48 hours (97% vs 79%; P < .01) than the control group. No between-group differences in procedural success or clinical success rates were found. At 3 months, the intervention group had a higher postintervention primary patency rate than the control group, although this did not reach statistical significance (58% vs 48%; P = .06). After stratification into native or graft accesses, the patency benefit was observed in the native access group (68% vs 50%; P = .03) but not in the graft access group (50% vs 46%; P = .65). After adjusting for potential confounders, timely thrombectomy remained an independent predictor of postintervention primary patency (hazard ratio, 0.449; 95% confidence interval, 0.224-0.900; P = .02) for native dialysis accesses.

CONCLUSIONS

Our results suggest that a timely thrombectomy approach, in which salvage is attempted within 24 hours of thrombosis diagnosis, improves postintervention primary patency of native but not graft accesses for dialysis.

Stent tunnel technique to save thrombosed native hemodialysis fistula with extensive venous aneurysm

INTRODUCTION AND PURPOSE

The increasing number of patients undergoing hemodialysis and the limited number of access sites have resulted in an increasing number of techniques to maintain vascular access for hemodialysis. Thrombosed arteriovenous (AV) fistulas with large venous aneurysms have poor treatment results, with both endovascular and surgical techniques, leading to a high rate of definitive AV access loss. The purpose of this study was to review the feasibility and initial results of this novel endovascular treatment of thrombosed AV fistulas with large venous aneurysms.

MATERIALS AND METHODS

A novel endovascular treatment technique of inserting nitinol auto-expandable uncovered stents stretching through the whole puncture site area, thus creating a tunnel inside the thrombus, was retrospectively analyzed and described.

RESULTS

A total of 17 stents were placed in 10 hemodialysis fistulas, with a mean venous coverage length of 17.8 cm. In all the cases, 100% technical success was achieved, with complete restoration of blood flow in all patients. There were no procedure-related complications. The mean follow-up was 167 days (range 60-420 days), with a primary and assisted patency of 80% and 100%, respectively. No multiple trans-stent struts-related complications were observed. Three stent fractures were diagnosed with plain films at the site of puncture without consequence in the venous access permeability.

CONCLUSION

The "stent tunnel technique" is a feasible, safe and effective alternative to salvage native hemodialysis access, thus extending the function of the venous access with no signs of stent-related complications and a respectable midterm patency.

Percutaneous treatment of thrombosed hemodialysis arteriovenous fistulas: use of thromboaspiration and balloon angioplasty

Background

Endovascular strategies have been used to manage patients with thrombosed vascular access for hemodialysis. We analyzed primary success rate and patency rates of balloon angioplasty following mechanical thrombectomy for the treatment of thrombosed native arteriovenous fistulas.

Methods

This was a retrospective study of 24 patients with thrombosed native arteriovenous fistulas who were referred for treatment in the intervention unit of the Radiology Department. All patients had been performed percutaneous thrombo-aspiration and balloon angioplasty. Technical and clinical success rates as well as the 6th and 12th months primary and secondary patency of fistulas were evaluated.

Results

Technical and clinical success was 83%. In the 6 of 20 patients, early re-thrombosis were detected. Patent AVF with primary and secondary patency rates at 6 and 12 months was 55%-40%. The secondary patency rates at 6 and 12 months were 75% and 70%.

Conclusion

Mechanical thrombectomy with balloon angioplasty is a minimally invasive and effective procedure for the treatment of thrombosed native arteriovenous fistula. Advantages of this technique are minor complication rates, cost effectiveness, high technical success rate.

Arteriovenous fistula patency in the 3 years following vonapanitase and placebo treatment

OBJECTIVE

This study explored the long-term outcomes of arteriovenous fistulas treated with vonapanitase (recombinant human elastase) at the time of surgical creation.

METHODS

This was a randomized, double-blind, placebo-controlled trial of 151 patients undergoing radiocephalic or brachiocephalic arteriovenous fistula creation who were randomized equally to placebo, vonapanitase 10 μg, or vonapanitase 30 μg. The results after 1 year of follow-up were previously reported. The current analysis occurred when the last patient treated was observed for 3 years. For the current analysis, the primary end point was primary patency; the secondary end points included secondary patency, use of the fistula for hemodialysis, and rate of procedures to restore or to maintain patency.

RESULTS

There was no significant difference in the risk of primary patency loss with vonapanitase 10 μg or 30 μg vs placebo. When seven initial patency loss events related to cephalic arch and central vein balloon angioplasty were excluded, the risk of patency loss was reduced with vonapanitase overall (hazard ratio [HR], 0.63; P = .049) and 30 μg (HR, 0.51; P = .03). In patients with radiocephalic fistulas (n = 67), the risks of primary and secondary patency loss were reduced with 30 μg (HR, 0.37 [P = .02] and 0.24 [P = .046], respectively). The rate of procedures to restore or to maintain fistula patency was reduced with 30 μg vs placebo (0.23 vs 0.72 procedure days/patient/year; P = .03) and also reduced in patients with radiocephalic fistulas with 30 μg vs placebo (0.17 vs 0.85 procedure days/patient/year; P = .048).

CONCLUSIONS

In this study, vonapanitase did not significantly improve primary patency in the primary analysis but did significantly improve primary patency in an analysis that excluded patency loss due to cephalic arch and central vein balloon angioplasty. In patients with radiocephalic fistulas, 30 μg significantly improved primary and secondary patency. Vonapanitase 30 μg decreased the rate of procedures to restore or to maintain patency in the analysis that included all patients and in the subset with radiocephalic fistulas.

Endovascular recanalization of a thrombosed native arteriovenous fistula complicated with an aneurysm: technical aspects and outcomes

OBJECTIVE

To evaluate the technical aspects and outcomes of endovascular recanalization of a thrombosed native arteriovenous fistula (AVF) complicated with an aneurysm.

MATERIALS AND METHODS

Sixteen patients who had a thrombosed AVF complicated with an aneurysm (two radiocephalic and 14 brachiocephalic) were included in this study. Recanalization procedures were performed by mechanical thrombectomy using the Arrow-Trerotola percutaneous thrombectomy device and adjunctive treatments. We evaluated dose of thrombolytic agent, underlying stenosis, procedure time, technical and clinical success, and complications. The primary and secondary patency rates were calculated using the Kaplan-Meier analysis.

RESULTS

The thrombolytic agents used were 100000 U urokinase mixed with 500 IU heparin (n = 10) or a double dose of the mixture (n = 6). The thrombi in aneurysms were removed in all but two patients with non-flow limiting residual thrombi. One recanalization failure occurred due to a device failure. Aspiration thrombectomy was performed in 87.5% of cases (n = 14). Underlying stenoses were found in the outflow draining vein (n = 16), arteriovenous anastomosis or juxtaanastomosis area (n = 5), and the central vein (n = 3). Balloon angioplasty was performed for all stenoses in 15 patients. Two patients with a symptomatic central vein stenosis underwent insertion of a stent after balloon angioplasty. Mean procedure time was 116.3 minutes. Minor extravasation (n = 1) was resolved by manual compression. Both technical and clinical success rates were 93.8% (n = 15). The primary patency rates at 3, 6, and 12 months were 70.5%, 54.8%, and 31.3%, respectively. The secondary patency rates at 3, 6, and 12 months were 70.5%, 70.5%, and 47.0%, respectively.

CONCLUSION

Thrombosed AVF complicated with an aneurysm can be successfully recanalized, and secondary patency can be prolonged with endovascular treatment.

Percutaneous Rheolytic Thrombectomy of Thrombosed Autogenous Dialysis Fistulas

Purpose: To retrospectively analyze the technical and clinical outcome of percutaneous rheolytic thrombectomy with the use of the AngioJet device in thrombosed autogenous arteriovenous dialysis fistulas. Methods: A cohort of 38 consecutive patients (24 men; mean age 70.7±13.8 years) presenting with 59 thrombotic events in 39 autogenous dialysis fistulas were retrospectively analyzed. The AngioJet rheolytic thrombectomy device was used in all cases. Adjunctive therapies, as well as procedure-related complications, were noted. Primary, assisted primary, and secondary patency of the autogenous fistulas was assessed along with factors potentially influencing patency. Results: Initial technical success to recanalize the efferent vein was 100% (n=59), and a successful postprocedure dialysis session was possible in 97% (n=57) of cases. Adjunctive procedures included percutaneous thromboaspiration (n=4, 7%), balloon angioplasty (n=59, 100%), and stent placement (n=16, 27%). Complications related to thrombectomy occurred in 3 (5%) procedures (distal arterial embolus). Primary, assisted primary, and secondary patency rates at 12 months were 56.1% (95% CI 42.8% to 75.2%), 61.6% (95% CI 48.6% to 74.7%), and 86.2% (95% CI 74.9% to 97.5%), respectively. Risk factors for early fistula occlusion were greater patient age (p=0.045), the age of the fistula (p=0.045), previous stent insertion (p=0.019), and an upper arm fistula (p=0.047). Conclusion: Percutaneous rheolytic thrombectomy of autogenous dialysis fistulas is effective in restoring patency and allowing subsequent hemodialysis. The complication rate is acceptably low, and the large majority of the fistulas are still used for hemodialysis at 1-year follow-up. Older fistulas and upper arm fistulas are at higher risk for early rethrombosis.

Pharmacomechanical thrombolysis for the treatment of thrombosed native arteriovenous fistula: a single-center experience

Background

Native arteriovenous fistula is one of the important routes for hemodialysis patients because of increased long-term survival and preservation of quality of life. We reported on a single-center experience with using pharmacomechanical thrombolysis for the treatment of thrombosed native arteriovenous fistula.

Material/Methods

This was a retrospective study of 12 hemodialysis patients (8 males and 4 females) with 14 thrombosed distal forearm Brescia-Cimino radiocephalic fistulas who were referred for pharmacomechanical thrombolytic treatment in the intervention unit of the Radiology Department, from 1 January 2010 to 30 December 2011. Demographic data, technical success rates, clinical success rates and complications were evaluated. The patency was evaluated by Kaplan-Meier analysis.

Results

The technical and clinical success was found in 12 thrombosed fistulas. Only 3 procedures had minor complications including small amounts of adjacent soft tissue hematoma. There were no procedure-related major complications. The primary patency rates at 6 and 12 months were 67% and 50%. The secondary patency rates at 6 and 12 months were 75% and 67%.

Conclusions

Pharmacomechanical thrombolysis is a minimally invasive, effective, durable, and safe procedure for the treatment of thrombosed native arteriovenous fistula. This procedure can be considered as an alternative treatment for thrombosed dialysis fistulas.

Treatment of hemodialysis vascular access rupture irresponsive to prolonged balloon tamponade: retrospective evaluation of the effectiveness of N-butyl cyanoacrylate seal-off technique

OBJECTIVE

The current study retrospectively evaluated whether the percutaneous N-butyl cyanoacrylate (NBCA) seal-off technique is an effective treatment for controlling the angioplasty-related ruptures, which are irresponsive to prolonged balloon tamponade, during interventions for failed or failing hemodialysis vascular accesses.

MATERIALS AND METHODS

We reviewed 1588 interventions performed during a 2-year period for dysfunction and/or failed hemodialysis vascular access sites in 1569 patients. For the angioplasty-related ruptures, which could not be controlled with repeated prolonged balloon tamponade, the rupture sites were sealed off with an injection of a glue mixture (NBCA and lipiodol), via a needle/needle sheath to the rupture site, under a sonographic guidance. Technical success rate, complications and clinical success rate were reported. The post-seal-off primary and secondary functional patency rates were calculated by a survival analysis with the Kaplan-Meier method.

RESULTS

Twenty ruptures irresponsive to prolonged balloon tamponade occurred in 1588 interventions (1.3%). Two technical failures were noted; one was salvaged with a bailout stent-graft insertion and the other was lost after access embolization. Eighteen accesses (90.0%) were salvaged with the seal-off technique; of them, 16 ruptures were completely sealed off, and two lesions were controlled as acute pseudoaneurysms. Acute pseudoaneurysms were corrected with stentgraft insertion in one patient, and access ligation in the other. The most significant complication during the follow-up was delayed pseudoaneurysm, which occurred in 43.8% (7 of 16) of the completely sealed off accesses. Delayed pseudoaneurysms were treated with surgical revision (n = 2), access ligation (n = 2) and observation (n = 3). During the follow-up, despite the presence of pseudoaneurysms (acute = 1, delayed = 7), a high clinical success rate of 94.4% (17 of 18) was achieved, and they were utilized for hemodialysis at the mean of 411.0 days. The post-seal-off primary patency vs. secondary patency at 90, 180 and 360 days were 66.7 ± 11.1% vs. 94.4 ± 5.4%; 33.3 ± 11.1% vs. 83.3 ± 8.8%; and 13.3 ± 8.5% vs. 63.3 ± 12.1%, respectively.

CONCLUSION

Our results suggest that the NBCA seal-off technique is effective for immediate control of a venous rupture irresponsive to prolonged balloon tamponade, during interventions for hemodialysis accesses. Both high technical and clinical success rates can be achieved. However, the treatment is not durable, and about 40% of the completely sealed off accesses are associated with developed delayed pseudoaneurysms in a 2-month of follow-up. Further repair of the vascular tear site, with surgery or stent-graft insertion, is often necessary.

Declotting, maintenance, and avoiding procedural complications of native arteriovenous fistulae

Native arteriovenous fistulae are the best form of hemodialysis access. Every effort should be made to preserve and maintain these valuable access sites. The typical fistula is created from the distal radial artery to an adjacent forearm vein. Thrombosis is a relatively rare occurrence but when it occurs, surgical declotting is not as successful as percutaneous approaches. Thus, the interventional radiologist needs to be prepared to evaluate and declot fistulae. As the percentage of fistulae increases in the general dialysis population, radiologists expect to see the demand for percutaneous declotting increase. This article reviews approaches to declotting and maintaining fistulae. Common procedural complications and their treatment or follow-up are also reviewed.

Hybrid surgery versus percutaneous mechanical thrombectomy for the thrombosed hemodialysis autogenous arteriovenous fistulas

Purpose

For the successful treatment of thrombosed autogenous arteriovenous fistula (AVF), we designed and performed a hybrid surgery. Its clinical outcomes were compared with those of percutaneous mechanical thrombectomy, retrospectively.

Methods

Forty cases of thrombosed autogenous AVFs underwent hybrid surgery, whereas 19 cases received percutaneous mechanical thrombectomy. Hybrid surgery consisted of surgical thrombectomy, balloon angioplasty and/or additional surgical angioplasty. Percutaneous mechanical thrombectomy included catheter-introduced thrombus aspiration, balloon angioplasty and/or stenting. Procedure related outcomes such as technical success rates and primary patency rates were analyzed, retrospectively.

Results

There were no statistically significant differences between the two groups in terms of demographic data of the patients including age, gender, diabetes status, and frequency of antiplatelet use, as well as the characteristics of thrombosed autogenous AVFs such as access age, site, type, and length of time between thrombosis and AVF creation (P > 0.05). Technical success rates (92.5% vs. 68.4%, P = 0.005, respectively) and primary patency rates (85.9% vs. 36.8% at 6 months, 81.1% vs. 26.3% at 12 months, 81.1% vs.21.1% at 18 and 24 months respectively, log-rank test, (P < 0.001) were significantly higher in the hybrid surgery group. In terms of cost analysis, supply cost was not different (P = 0.065), but total cost was statistically lower in the hybrid surgery group (P = 0.019).

Conclusion

Hybrid surgery showed better technical success rates and patency rates in the salvaging of thrombosed autogenous AVFs than in percutaneous mechanical thrombectomy.

Percutaneous treatment of thrombosed arteriovenous fistulas: clinical and economic implications

BACKGROUND AND OBJECTIVES

Maintenance of previously thrombosed arteriovenous fistulas (AVFs) as functional vascular accesses can be highly expensive, with relevant financial implications for healthcare systems. The aim of our study was to evaluate the costs and health outcomes of vascular access care in hemodialysis patients with AVF thrombosis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A retrospective, controlled cohort study was performed among local hemodialysis patients with completely thrombosed AVFs between August 1, 2007, and July 1, 2008. Detailed clinical and demographic information was collected and a comprehensive measure of total vascular access costs was obtained. Costs are reported in 2009 U.S. dollars.

RESULTS

A total of 63 consecutive hemodialysis patients with thrombosed AVFs were identified--a cohort of 37 patients treated with percutaneous thrombectomy and a historic cohort of 25 patients with abandoned thrombosed AVFs. The mean cost of all vascular access care at 6 months was $2479. Salvage of thrombosed AVFs led to a near two-fold reduction in access-related expenses, per patient-month at risk ($375 versus $706; P = 0.048). The costs for access-related hospitalizations ($393 versus $91; P = 0.050), management of access dysfunction ($106 versus $28; P = 0.005), and surgical interventions ($35 versus $6; P = 0.001) were also significantly lower in the percutaneous treatment group. At 6 months, most of these patients had a functional AVF as permanent vascular access (91% versus 33%, P = 0.0001).

CONCLUSIONS

Salvage of thrombosed AVF is a highly efficient procedure; therefore, intensive efforts should be undertaken to universalize these interventions.

The radiological management of the thrombosed arteriovenous dialysis fistula

Patent vascular access is a prerequisite for adequate haemodialysis, and is a major determinant of quality of life and long-term survival of patients with end-stage renal disease. Autogenous haemodialysis fistulas (AVFs) have demonstrated superior clinical outcome when compared to synthetic grafts, but both types of access remain susceptible to venous stenoses, and consequent thrombotic occlusion. Recent publications have reported primary patency rates of up to 100% following percutaneous de-clotting of AVFs incorporating techniques such as pharmacological thrombolysis, mechanical thrombectomy, and thrombo-aspiration. Endovascular management also provides information regarding the underlying cause of access thrombosis, with option to treat. Consequently, there has been a paradigm shift in the management of fistula thrombosis, with interventional radiology assuming a lead role in initial salvage procedures. This article will attempt to provide the reader with an insight into the multiple radiological techniques that can be employed to salvage a thrombosed AVF based on current published literature.

Endovascular revascularization of chronically thrombosed arteriovenous fistulas and grafts for hemodialysis: a retrospective study in 15 patients with 18 access sites

The current study retrospectively evaluated whether endovascular revascularization of chronically thrombosed and long-discarded vascular access sites for hemodialysis was feasible. Technical and clinical success rates, postintervention primary and secondary patency rates, and complications were reported. During a 1-year period, we reviewed a total of 924 interventions performed for dysfunction and/or failed hemodialysis vascular access sites and permanent catheters in 881 patients. In patients whose vascular access-site problems were considered untreatable or were considered treatable with a high risk of failure and access-site abandonment, we attempted to revascularize (resurrect) the chronically occluded and long-discarded (mummy) vascular access sites. We attempted to resurrect a total of 18 mummy access sites (mean age 46.6 ± 38.7 months; range 5-144) in 15 patients (8 women and 7 men; mean age 66.2 ± 11.5 years; age range 50-85) and had an overall technical success rate of 77.8%. Resurrection failure occurred in 3 fistulas and in 1 straight graft. The clinical success rate was 100% at 2 months after resurrection. In the 14 resurrected vascular access sites, 6 balloon-assisted maturation procedures were required in 5 fistulas; after access-site maturation, a total of 22 interventions were performed to maintain access-site patency. The mean go-through time for successful resurrection procedures was 146.6 ± 34.3 min (range 74-193). Postmaturation primary patency rates were 71.4 ± 12.1% at 30 days, 57.1 ± 13.2% at 60 days, 28.6 ± 13.4% at 90 days, and 19 ± 11.8% at 180 days. Postmaturation secondary patency rates were 100% at 30, 60, and 90 days and 81.8 ± 11.6% at 180 days. There were 2 major complications consisting of massive venous ruptures in 2 mummy access sites during balloon dilation; in both cases, prolonged balloon inflation failed to achieve hemostasis, but percutaneous N-butyl cyanoacrylate glue seal-off was performed successfully. Percutaneous resurrection of mummy vascular access sites for hemodialysis is technically feasible with high clinical success rates. In selected patients, resurrection of mummy access sites provides long-discarded access sites one more chance to be used for hemodialysis in an effort to preserve potential extremity sites for future access-site placement and to prevent long-term catheter indwelling.

Radial arterial approach with adjunctive urokinase for treating occluded autogenous radial-cephalic fistulas

There are no data regarding the feasibility and safety of a radial arterial approach with adjunctive urokinase for treating occluded autogenous radial-cephalic fistulas. We retrospectively examined 54 transradial interventions performed to treat occluded autogenous radial-cephalic fistulas within 72 h of occurrence. Urokinase was used in patients with a large thrombus burden. A total of 92 lesions in 54 consecutive patients (27 males, 27 females; mean age, 61.8+/-12.3 years) were treated via radial access. All radial punctures were successful except in one patient. Most thrombotic lesions were located within 1 cm of the radiocephalic anastomosis (79.6%). The mean length of treated thrombotic lesions was 10.3+/-5.4 cm (range, 4-32 cm). Twenty-five patients (46.3%) received urokinase (mean dose, 96,000+/-30,000 U). After transradial intervention, systolic, diastolic, and mean pressures in the radial artery decreased from 179+/-41, 77+/-17, and 111+/-22 mm Hg to 71+/-29, 36+/-15, and 48+/-19 mm Hg (all p's\0.001), respectively. Four radial interventions were unsuccessful. The anatomic and clinical success rates of the radial approach were both 92.6%; postinterventional primary patency rates were 65% at 6 months and 40% at 12 months. Two minor vascular complications were noted, one caused by guidewire-induced contrast extravasation and the other by balloon-induced contrast extravasation. No patient developed clinical signs of pulmonary embolism. In conclusion, the radial approach with adjunctive urokinase is an effective and safe approach to treat occluded autogenous radial-cephalic fistulas.

[Doppler sonography of arteriovenous fistulas for haemodialysis]

BACKGROUND

Permanent and reliable vascular access is of utmost importance for patients (with chronic renal failure) in need of haemodialysis. Autogenous arteriovenous fistula (AVF) on the forearm are robust and have the benefits of providing long-term access with relatively few complications. The main problem is insufficient blood flow due to stenoses requiring early intervention. The AVF therefore needs surveillance with regular clinical examination supplemented with imaging. In recent years Doppler sonography has gained an increasingly important role in the assessment of AVFs. This paper discusses AVFs and frequent complications and stresses the benefit of Doppler sonography in the planning and surveillance of AVFs.

MATERIAL AND METHODS

The survey is based on literature retrieved from a PubMed search, and our experience from sonographic examinations of AVFs in the Central Hospital of Lillehammer, Norway.

RESULTS

Doppler sonography is a non-invasive imaging modality without discomfort for the patient, and well suited for examination of AVFs. The method has a high sensitivity for detection of stenoses and other AVF-related problems, and can provide a detailed image of the course and diameter of blood vessels, with quantitative measurement of blood flow. Indications for Doppler sonography are preoperative mapping, assessment of fistula problems and maturity; it is also a useful method for continuous surveillance of fistulas.

INTERPRETATION

Doppler sonography can be used for immediate treatment of patients with sudden AVF problems; and if necessary endovascular intervention or surgery can follow. Recent European guidelines recommend the method as a standard procedure before and after creation of an AVF. Doppler sonography should have a central position in a multidisciplinary teamwork on surveillance of patients with AVFs in need of haemodialysis.