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.

Management of Thrombosed Dialysis Access Circuits

Thrombotic occlusion of autologous arteriovenous fistulas or synthetic arteriovenous grafts is a serious adverse event in hemodialysis patients and declotting should be performed before next hemodialysis session, in order to avoid a central venous catheter. Various techniques exist to declot a thrombosed vascular access, including open surgical thrombectomy, catheter-directed thrombolysis and use of different types of percutaneous thrombo-aspiration catheters and mechanical thrombectomy devices. These devices can be categorized as devices with direct wall contact and hydrodynamic devices without direct wall contact. Technical and early clinical outcome results of percutaneous hemodialysis declotting are high and ranging between 70 and 100%; late clinical patency results are much lower related to restenosis or re-thrombosis; these patency results are higher for autologous arteriovenous fistulas compared to synthetic arteriovenous grafts and mainly depend on the combined efficacy of successful thrombectomy and durable treatment of the underlying stenoses, associated with the acute thrombosis.

Catheter-directed thrombolytic infusion for thrombosed arteriovenous fistulas with a large clot burden: A case series

Arteriovenous fistula (AVF) thrombosis occurs less often when compared to arteriovenous grafts. Since the number of AVFs has increased in the United States, AVF thrombosis is seen more frequently today. AVF thrombectomy can be tedious, requires physician ingenuity, and many times results in failure. Substantial clot burden in megafistulas and aneurysms is considered a relative contraindication to endovascular thrombectomy. Usually, it results in surgical referral for open thrombectomy or, at times, abandonment of the fistula altogether. Herein, we describe the technique, results, and cautions of combining a continuous infusion of recombinant tissue plasminogen (rTPA) followed by angioplasty of the culprit stenotic lesion that was successful in opening five of six AVFs with a substantial clot burden.

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.

Ultrasound-guided removal of organized thrombi using biopsy forceps in dialysis patients with arterio-venous access occlusion

INTRODUCTION

As a countermeasure against the organized thrombi frequently observed in vascular access occlusion, we devised a percutaneous excision method for organized thrombi under superficial ultrasound guidance using biopsy forceps. The Radial JawTM 3 (2 mm) biopsy forceps of Boston Scientific Corporation was used. The usefulness of this method was investigated.

METHOD

The following protocol, which is suitable for endovascular treatment, was prepared and used: (1) all procedures were performed under ultrasound guidance and (2) use of the forceps was assisted via a long sheath in cases involving a complicated bloodstream.

SUBJECTS

Among 564 cases of arterio-venous access occlusion that received treatment at this hospital between May 2014 and April 2017, the subjects of this study were 468 cases who could be followed up. Thrombectomy of an organized thrombus using the biopsy forceps was performed 194 times in 138 cases. Biopsy forceps were used in the initial treatment in a total of 115 cases, including 71 cases of acute occlusion of an autologous vein, 3 cases of chronic occlusion of an autologous vein, and 41 cases of acute occlusion of a prosthetic vessel.

RESULTS

The initial success rate for all cases of occlusion was 97.2%. The initial success rate for cases in which biopsy forceps were used was 98.2%. For cases using biopsy forceps, the primary patency rates were 47.1% at 3 months, and the secondary patency rates (until occlusion) were 89.1% at 3 months.

CONCLUSION

This method was considered to be a valuable choice as a countermeasure against organized thrombi.

Thrombosed native hemodialysis fistulas: Technical and clinical outcomes of endovascular recanalization and factors influencing patency

Purpose:

To evaluate the technical and clinical results of endovascular recanalization of thrombosed native hemodialysis fistula and the factors influencing patency.

Methods:

A retrospective study was conducted with 73 patients who had thrombosed arteriovenous fistulas and were treated with endovascular methods. Patient characteristics, arteriovenous fistula-related characteristics, and endovascular procedures were analyzed. Technical and clinical results and patency rates were evaluated. The factors influencing patency were analyzed using a univariate and multivariate Cox proportional hazards model.

Results:

Technical and clinical success rates were 93% (68/73) and 85% (62/73), respectively. At 3, 6, and 12 months, the primary patency rates were 87.9%, 73.3%, and 64.8%; assisted primary patency rates were 89.2%, 78.6%, and 70.7%; and secondary patency rates were 90.8%, 87.2%, and 83.1%, respectively. Previous intervention and cephalic arch stenosis were risk factors for lower primary and assisted primary patency ( p < 0.05 for all). Cephalic arch stenosis was the only risk factor for lower secondary patency ( p < 0.05). No major complications associated with the procedures were noticed.

Conclusion:

Endovascular treatment was effective for the immediate recanalization of thrombosed arteriovenous fistula. In addition, previous intervention and cephalic arch stenosis were significantly related to lower arteriovenous fistula patency.

Comparative efficacy and safety of local and peripheral venous thrombolytic therapy with urokinase for thrombosed hemodialysis arteriovenous fistulas

Arteriovenous fistula (AVF) thrombosis is a common complication in patients undergoing hemodialysis, and early intervention is required. Urokinase has been used as a thrombolytic agent for declotting the thrombosed access. However, the optimal route for infusing urokinase remains to be determined. In the present retrospective observational study, 49 patients who underwent local venous infusion and 57 patients with peripheral venous infusion of urokinase were included. A urokinase dosage of 300,000 U was administered until successful thrombolysis, which was a maximum of three times. Age, sex, period of dialysis, time of AVF placement, systolic and diastolic blood pressure and thrombus age were similar between the two groups. The efficacy of urokinase infusion via the two routes in resolving thrombosed AVFs, defined as successful fibrinolysis, and the safety, defined as the number of bleeding events, was compared. The cumulative thrombolysis success rate following three sessions of thrombolytic therapy in the local venous thrombolysis group was higher compared with that in the peripheral venous thrombolysis group (85.7 vs. 68.4%; P=0.04). The local thrombolysis group exhibited less ecchymosis (4.1 vs. 14.0%; P=0.07), epistaxis (2.0 vs. 10.5%; P=0.08) and gingival bleeding (4.1 vs. 19.3%; P=0.02) events compared with the peripheral thrombolysis group. Further analyses demonstrated that systolic [odds ratio (OR)=1.10; 95% confidence interval (CI), 1.03-1.17; P<0.01] and diastolic (OR=1.08; 95% CI, 1.02-1.14; P<0.05) blood pressure were protective factors, whereas thrombus age (OR=0.91; 95% CI, 0.84-0.99; P<0.05) was a risk factor for thrombolysis success among patients who underwent local thrombolytic therapy. Overall, the results suggest that local venous infusion of urokinase is superior to peripheral venous infusion for the treatment of patients with thrombosed fistulas.