Clinical effectiveness of open thrombectomy for thrombosed autogenous arteriovenous fistulas and grafts

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.

Maintenance and Salvage of Hemodialysis Access

Many end-stage kidney failure patients require hemodialysis as a life-sustaining treatment. Hemodialysis access via arteriovenous fistula or graft creation is preferred over long-term dialysis catheters, but intervention to maintain patency and prevent access failure is common. Endovascular and open surgical techniques are both utilized to address the underlying etiology of failure. Endovascular options include balloon angioplasty, angioplasty with stenting, and drug-eluting stents. Open revision is commonly needed for recurrent stenosis, aneurysmal or pseudoaneurysmal change, hemodialysis access-induced distal ischemia, and infection. Treatment plans should be guided by patient's individualized goals of care and require a multidisciplinary approach to the management of this complex disease.

Outcome and Risk Factors of Restenosis Post Percutaneous Transluminal Angioplasty at Juxta-Anastomotic of Wrist Autogenous Radial-Cephalic Arteriovenous Fistulas: A Retrospective Cohort Study

BACKGROUND

This retrospective cohort study was to determine the factors related to restenosis post percutaneous transluminal angioplasty (PTA) at juxta-anastomotic of wrist radial-cephalic arteriovenous fistulas (RC-AVFs).

METHODS

We conducted a retrospective study of patients who underwent their first PTA for juxta-anastomotic stenosis at RC-AVF from January 1, 2016, to December 31, 2020. Patient and stenotic lesion characteristics and PTA procedure factors were included in the analysis. The primary and assisted primary patency post PTA of RC-AVFs were evaluated using the Kaplan-Meier analysis and log-rank test. A Cox proportional hazard model was used to identify factors associated with restenosis post PTA. The receiver operating characteristic (ROC) curve was employed to evaluate the predictive value of the risk factors for restenosis post PTA.

RESULTS

A total of 65 patients with a mean age of 59.09 ± 14.94 years were enrolled in the study. The mean RC-AVF age was 9.2 (4.9, 35.05) months, and the median time of intervention for stenosis was 10.8 (4.05, 41.35) months after AVF creation. The primary patency rates following the first PTA at 3, 6, 12, and 24 months were 93.9, 84.6, 63.1, and 55.4%, respectively. The assisted primary patency rates at 3, 6, 12, and 24 months were 95.4, 90.8, 87.7, and 84.6%, respectively. Cox proportional hazard regression analysis revealed the maximum balloon diameter >5 mm had a lower postoperative restenosis rate compared with the maximum balloon diameter ≤5 mm (hazard ratio = 0.422; 95% confidence interval [CI]: 0.201-0.884; P = 0.022). ROC curve analysis showed that the area under the curve of the maximum balloon diameter during PTA was 0.624 (95% CI, 0.486-0.762). The best critical value for the maximum balloon diameter was 6 mm, the sensitivity was 64.5%, and the specificity was 61.8%.

CONCLUSIONS

For the first PTA at juxta-anastomotic of wrist RC-AVFs without thrombosis and complete occlusion, the use of a balloon with a maximum diameter of ≤5 mm is a risk factor to the occurrence of restenosis within 12 months post PTA. The result may help in tailoring surveillance programs in patients with RC-AVF stenosis.

[Acute interventions-dialysis shunt recanalization]

BACKGROUND

An arteriovenous fistula is vital for patients who need regular hemodialysis. Continuous patency and sufficient functionality determine quality of life and associated morbidity and mortality of patients.

PROBLEM

Following successful hemodialysis shunt creation, intimal hyperplasia and consecutive thrombosis or complete occlusion may cause different types of shunt dysfunctionality or even critical failure.

OBJECTIVE

Immediate shunt recanalization and revision by using an endovascular-first approach is crucial for long-term survival of hemodialysis fistula. There are several mechanisms available for catheter-based thrombus removal to unmask the typically underlying shunt stenosis.

METHODS

Primary technical recanalization success rates are very similar for clot cleaning. Treatment of intimal hyperplasia is preferably addressed by using drug-coated balloon angioplasty to allow for increased shunt patency compared to plain old balloon angioplasty. Stents and stent grafts are only used for resistant or repeated short-term recurrence of severe stenosis. Finally, surgical revision has a classical role in case of repeated failure of endovascular measures.

Endovascular Management of Thrombosed Dialysis Vascular Circuits

A functional hemodialysis vascular access is the lifeline for patients with end-stage kidney disease and is considered a major determinant of survival and quality of life in this patient population. Hemodialysis therapy can be performed via arteriovenous fistulas, arteriovenous grafts, and central venous catheters (CVCs). Following dialysis vascular access creation, the interplay between several pathologic mechanisms can lead to vascular luminal obstruction due to neointimal hyperplasia with subsequent stenosis, stasis, and eventually access thrombosis. Restoration of the blood flow in the vascular access circuit via thrombectomy is crucial to avoid the use of CVCs and to prolong the life span of the vascular access conduits. The fundamental principles of thrombectomy center around removing the thrombus from the thrombosed access and treating the underlying culprit vascular stenosis. Several endovascular devices have been utilized to perform mechanical thrombectomy and have shown comparable outcomes. Standard angioplasty balloons remain the cornerstone for the treatment of stenotic vascular lesions. The utility of drug-coated balloons in dialysis vascular access remains unsettled due to conflicting results from randomized clinical trials. Stent grafts are used to treat resistant and recurrent stenotic lesions and to control extravasation from a ruptured vessel that is not controlled by conservative measures. Overall, endovascular thrombectomy is the preferred modality of treatment for the thrombosed dialysis vascular conduits.

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

OBJECTIVE

Maintenance of functional arteriovenous grafts (AVGs) for dialysis is difficult secondary to low primary patency, need for reinterventions, and limited alternative dialysis access options. We assessed our experience with percutaneous thrombectomy for treatment of occluded AVGs.

METHODS

We performed a retrospective analysis of all percutaneous thrombectomies for AVGs from 2015 to 2017. These were generally performed using mechanical thrombectomy and occasional chemical tissue plasminogen activator thrombolysis, over-the-wire balloon embolectomy for inflow, and adjunctive inflow and outflow interventions as necessary. Perioperative outcomes, long-term patency, reinterventions, and need for new permanent access placement were analyzed.

RESULTS

There were 218 percutaneous thrombectomies performed on 86 AVGs in 77 patients. Approximately half (53.2%) of the patients were male and 68.8% were black. Mean age was 61.1 ± 13.0 years. At the time of thrombectomy, 73.8% underwent venous outflow interventions and 4.5% underwent arterial inflow interventions. Within 30 days, 24.8% of declotted grafts underwent repeated percutaneous thrombectomy, 14.3% required tunneled dialysis catheter placement, 4% developed minor access site or graft infections, and one patient underwent surgical arterial thrombectomy for arm ischemia. There were no venous thromboembolic, cardiopulmonary, or cerebrovascular complications or clinically significant pulmonary embolism. At 1 year and 3 years after percutaneous thrombectomy, freedom from repeated thrombosis was 37% and 18%, respectively, and freedom from new dialysis access placement was 66% and 51%, respectively. Overall patient survival was 82% at 3 years.

CONCLUSIONS

Percutaneous thrombectomy of AVGs is safe and is associated with acceptable patency rates. This minimally invasive method extends AVG use for these high-risk patients with limited dialysis access options.

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.

Angiography and phlebography in a hemodialysis population: A retrospective analysis of interventional results

OBJECTIVE

To clarify the reasons and beneficial effects and duration of arteriovenous fistula patency after radiological interventions in arteriovenous fistula. The patients investigated were referred due to arteriovenous fistula access flow problems.

MATERIAL AND METHODS

In 174 patients, 522 radiological investigations and endovascular treatments such as percutaneous transluminal angioplasty were analyzed, retrospectively. All investigations were performed due to clinical suspicion of impaired arteriovenous fistula function.

RESULTS

Arterial stenosis was significantly more frequent among patients with diabetic nephropathy (p < 0.001) and interstitial nephritis (p < 0.001). According to the venous stenosis, the diagnosis did not affect the frequency (p = 0.22) or the degree (p = 0.39) of stenosis. The degree of stenosis prior to percutaneous transluminal angioplasty correlated significantly with the degree of remaining stenosis after intervention (p < 0.001). Of the 174 patients, 123 (71%) performed a total of 318 investigations including percutaneous transluminal angioplasty. Repeated percutaneous transluminal angioplasty was performed significantly more often in patients with diabetic nephropathy. The median times to the first percutaneous transluminal angioplasty and to the subsequent percutaneous transluminal angioplasties were 9.5 and 5 months, respectively. Arteriovenous fistula in patients with diabetic nephropathy performed similar to most other diagnoses, although performing more percutaneous transluminal angioplasty/patient than most other diagnoses.

CONCLUSION

Many patients could maintain long-term patency of arteriovenous fistula, including those with diabetic nephropathy, with repeated interventions; this motivates a closer follow-up for these patients. Clinically significant stenosis should be dilated as meticulously and as soon as possible. Occlusions of the arteriovenous fistula in most instances can be successfully thrombolyzed or dilated upon early diagnosis.