Mechanical Thrombectomy in Acute Thrombosis of Dialysis Arteriovenous Fistulae and Grafts Using a Vacuum-Assisted Thrombectomy Catheter: A Multicenter Study

Impact of COVID-19 pandemic on hemodialysis access thrombosis

BACKGROUND

Delay in care of suspected stenosis or thrombosis can increase the chance of losing a functioning hemodialysis access. Access to care and resources were restricted during the COVID-19 pandemic. To evaluate the impact of the pandemic on arteriovenous fistula (AVF) and arteriovenous graft (AVG) procedures we have assessed the number and success of thrombectomies done before and during the COVID-19 pandemic.

METHODS

We examined all AVF and AVG angiograms with and without interventions, including thrombectomies, performed at a single center during April 2017-March 2021 (pre-COVID-19 era) and April 2020-March 2021 (COVID-19 era).

RESULTS

The proportion of procedures that were thrombectomies was higher during the COVID-19 era compared to the pre-COVID-19 era (13.3% vs 8.7%, p = 0.009). The proportion of thrombectomy procedures was higher during COVID-19 for AVF (8.2% vs 3.0%, p < 0.001) but there was no difference for AVG (26.5% vs 27%, p = 0.99). There was a trend toward a higher likelihood of unsuccessful thrombectomy during COVID-19 (33.3% vs 20.4%, p = 0.08).

CONCLUSIONS

More dialysis access thromboses and unsuccessful thrombectomies were noted during the COVID-19 pandemic. This difference could be due to a delay in patients getting procedures to maintain their dialysis accesses.

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.

Acute problems of hemodialysis access: Thrombosis, aneurysms, symptomatic high-flow fistulas, and complications related to central lines

Hemodynamic complications frequently affect vascular access and are important causes of morbidity and mortality. We present a review of acute complications affecting vascular accesses, focusing on classical and new treatments. Acute complications in hemodialysis vascular access are often underestimated and undertreated, and can present a challenge for both vascular surgeons and anesthesiologists. Accordingly, we considered different anesthesiologic approaches to both hemorrhagic and nonhemorrhagic patients. A strict collaboration among nephrologists, surgeons, and anesthesiologists can potentially improve prevention and management of acute complications and quality of life.

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.

[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.

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.

Arteriovenous fistulas for hemodialysis: Brief review and current problems

The number of people worldwide living with end-stage renal disease is increasing. Arteriovenous fistulas are the preferred method of vascular access in patients who will require hemodialysis. As the number of patients with arteriovenous fistulas grows, the role of physicians who intervene who maintain and salvage these fistulas will grow in importance. This review aims to familiarize practitioners with the rationale for arteriovenous fistula creation, the detection of fistula dysfunction, and the state of the art on fistula maintenance and preservation. Current controversies are briefly reviewed.

Continuous Aspiration Thrombectomy in High- and Intermediate-High-Risk Pulmonary Embolism in Real-World Clinical Practice

Objectives

We sought to assess the technical and clinical feasibility of continuous aspiration catheter-directed mechanical thrombectomy (CDT) in patients with high- or intermediate-high-risk pulmonary embolism (PE).

Methods and Results

Fourteen patients (eight women and six men; age range: 29–71 years) with high- or intermediate-high-risk PE and contraindications to or ineffective systemic thrombolysis were prospectively enrolled between October 2018 and February 2020. The Indigo Mechanical Thrombectomy System (Penumbra, Inc., Alameda, California) was used as CDT device. Low-dose local thrombolysis (alteplase, 3–12 mg) was additionally applied in three patients. Technical and procedural success was achieved in 14 patients (100%). Complete or nearly complete clearance of pulmonary arteries was achieved in nine patients (64.3%), whereas partial clearance was achieved in five (35.7%). A significant improvement in the pre- and postprocedural patients' clinical status was observed in the following fields (median; interquartile range): heart rate (110; 100–120/min vs. 85; 80–90/min; p < 0.0001), systolic blood pressure (106; 90–127 mmHg vs. 123; 110–133 mmHg; p = 0.049), arterial oxygen saturation (88.5; 84.2–93% vs. 95.0; 93.8–95%, p = 0.0051), pulmonary artery systolic pressure (55; 44–66 mmHg vs. 42; 34–53 mmHg; p = 0.0015), Miller index score (21.5; 20–23 vs. 9.5; 8–13; p < 0.0001) and right ventricular/left ventricular ratio (1.3; 1.3–1.5 vs. 1.0; 0.9–1.0; p < 0.0001). No major periprocedural bleeding was detected.

Conclusions

CDT is a feasible and promising technique for management of high- or intermediate-high-risk PE to decrease thrombus burden, reduce right heart strain, and improve hemodynamic and clinical status. Some patients may benefit from simultaneous local low-dose thrombolytic therapy. Nevertheless, its criteria and role in CTD-managed patients require further elucidation.

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.

Vacuum-assisted mechanical thrombectomy in extensively occlusive thrombosis of dialysis arteriovenous grafts with indigo system

PURPOSE

To present a selected series of extensively occlusive thrombosis of arteriovenous graft treated with the Penumbra's Indigo System.

MATERIALS AND METHODS

Ten patients with acute (within 72 h) extensively occlusive thrombosis of arteriovenous graft (mean extension = 30.1 (range = 15-45) cm) were treated at our institution with the Indigo System. Of the 10 cases, thrombosis was extended to venous outflow in 7 cases and to both arterial inflow and venous outflow in 3 cases.

RESULTS

Both anatomic and clinical success were achieved in 8 of the 10 procedures (80.0%). In the 2 cases of technical failure, the patients underwent surgical thrombectomy with the finding of arteriovenous graft exhaustion, which was then replaced. The 6-month primary patency, primary-assisted patency, and secondary patency rates were 37.5% (3/8), 50.0% (4/8), and 62.5% (5/8). We reported 2 complications (one minor and one major adverse event).

CONCLUSION

Percutaneous mechanical thrombectomy aspiration with Indigo System is a relatively safe and effective procedure and can be used even in extensively thrombosed arteriovenous graft.

Single-center experience with Indigo aspiration thrombectomy for acute lower limb ischemia

OBJECTIVE

Acute lower limb ischemia (ALLI) is a challenging vascular emergency with notable morbidity. Aspiration mechanical thrombectomy (AMT) devices are an alternative approach to remove thrombus in the peripheral arterial system and to restore limb perfusion, but data are limited. We evaluated the outcomes of AMT for the treatment of ALLI at our institution.

METHODS

We performed a single-center retrospective review of patients with ALLI treated with Indigo (Penumbra Inc, Alameda, Calif) AMT device from 2014 to 2017. The primary outcome was technical success (restoration of blood flow with <50% residual thrombus without need for catheter-directed thrombolysis [CDT] or open surgery) as main treatment or adjunctive treatment (after failure of another modality). Indications, anatomic segments treated, outcomes, and complications were reviewed.

RESULTS

There were 41 patients (68% male, 32% female; mean age, 67 years; range, 27-90 years) who underwent 43 procedures. The cause of ALLI was embolism (18), native vessel thrombosis (13), bypass thrombosis (7), intraluminal thrombus due to pseudoaneurysm (1), stent thrombosis (1), intraprocedural embolization (1), recurrent thrombosis of native vessel (1), and chronic thrombosis (1). AMT was the main treatment in 29 cases and adjunctive in 14. Technical success was 52% (15/29) as main treatment and 50% (7/14) as adjunctive treatment. Thrombolysis was avoided in 53% of patients (23/43). There were six thrombotic recurrences, one after successful isolated AMT. The other five required multiple modalities after AMT failure. There were no 30-day deaths. Five patients required amputations, but only one after successful AMT. Complications included intraoperative distal embolization (two), access site hematoma (one), pseudoaneurysm (one), acute kidney injury (one), and spontaneous calf hematoma (one). There were no blood transfusions required or severe bleeding complications.

CONCLUSIONS

With an overall success rate of 51% in selected patients, the Indigo AMT device avoided the need for CDT or open surgery in about half of patients with ALLI. The device has a favorable safety profile, particularly in high-risk cases. Given its moderate effectiveness, the role of Indigo AMT in the management of ALLI will further be defined by the description of optimal technique, the determination of treatment indications, and a direct comparison with CDT.

Aspiration thrombectomy for the management of acute deep venous thrombosis in the setting of venous thoracic outlet syndrome

Objectives

Venous thoracic outlet syndrome, known by the eponym Paget–Schroetter syndrome, is seen in healthy, young individuals with “effort-induced thrombosis.” Endovascular therapies, including catheter-directed thrombolysis, have been described in the acute management of the upper extremity deep venous thrombosis; however, we assessed the technical success of treating this entity using a mechanical aspiration thrombectomy system.

Methods

This was a multi-center retrospective review of patients with venous thoracic outlet syndrome with acute thrombosis treated with the Indigo continuous aspiration mechanical thrombectomy system. Charts from patients with venous thoracic outlet syndrome and acute deep venous thrombosis treated with this system at our institution along with three data sharing locations were reviewed for demographics, deep venous thrombosis risk factors, imaging modalities used for diagnosis, extent of axillosubclavian deep venous thrombosis, treatment details, adjunctive therapies, and complications. The primary outcome was technical success (resolution of >70% of thrombus).

Results

There were 16 patients (50% male) with a mean age of 33 years (range 17–69 years). Six patients had underlying venous thromboembolism risk factors including use of contraceptives ( n = 2), prior deep venous thrombosis ( n = 3), and known thrombophilia ( n = 1). Fifteen patients had complete venous occlusion, and the extent of venous involvement included subclavian ( n = 14), axillary ( n = 16), and brachial ( n = 7). The majority (81.25%) of patients were treated in a single setting, and technical success was achieved in all cases with the use of adjunctive therapies. Only three patients required additional overnight thrombolytic therapy.

Conclusions

The Penumbra Indigo system, often in combination with adjunctive catheter-directed thrombolysis and venoplasty, is a safe and effective device for the treatment of acute upper extremity deep venous thrombosis in the setting of Paget–Schroetter syndrome. No patients experienced central embolization or post-operative renal insufficiency. One-third of patients avoided any additional catheter-directed thrombolysis exposure, and technical success was achieved in all cases. A single bleeding complication was observed in a patient undergoing overnight adjunctive catheter-directed thrombolysis. All patients maintained patency until time of first rib resection.

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.

Time to thrombectomy is associated with increased risk for dialysis catheter placement

BACKGROUND

Arteriovenous dialysis access, fistulae (AVF) or grafts (AVG), are associated with significant rates of thrombosis. Timely thrombectomy may have a significant impact on immediate and long-term access survival. However, switching to a catheter is associated with higher rates of morbidity and mortality compared with those who have an AVF or AVG.

OBJECTIVES

The goal of this study was to evaluate whether time to thrombectomy increases the risk for loss of dialysis access and subsequent placement of a dialysis catheter at hospital discharge, at 6 months, 12 months, and data at any time after discharge.

METHODS

Using retrospective data, 444 patients were identified as having undergone thrombectomy for dialysis access dysfunction between January 2008 and April 2015, with 122 hospital admissions primarily for thrombectomy.

RESULTS

The mean age was 60.4 years, 65% were male, and 44.3% had an arteriovenous fistula as their dialysis access. The mean time to thrombectomy was 10.8 hours, and 14 patients utilised a catheter for haemodialysis as primary access upon discharge. After adjustment for prior access intervention, access type, and time to thrombectomy, the adjusted odds ratios (AOR) of a one-day delay in thrombectomy was associated with a twofold increase in requirement for catheter at discharge and at 6 months. This association remained present at any time after discharge.

CONCLUSION

In this study of patients cared for within an academic health system, a single day delay in thrombectomy nearly doubled the risk of needing a dialysis catheter at hospital discharge, 6 months, or any time after discharge.

Aspiration thrombectomy for acute iliofemoral or central deep venous thrombosis

OBJECTIVE

The use of catheter-directed thrombolysis (CDT) may provide clinical benefit in patients with acute deep venous thrombosis (DVT), but significant doubt remains about its indications and risks. We assessed technical success in resolution of acute iliofemoral or central DVT after single-session treatment with a novel mechanical aspiration thrombectomy device as an alternative to initiation of CDT.

METHODS

This was a single-center retrospective review of patients with acute iliofemoral or central DVT treated with the Indigo continuous aspiration mechanical thrombectomy 8 system (Penumbra, Inc, Alameda, Calif) from 2016 to 2017. The primary outcome was technical success, defined as resolution of >70% of thrombus without need for postaspiration CDT, as an initial or adjunctive treatment. Secondary end points included DVT recurrence and treatment complications.

RESULTS

There were 10 patients (50% male) with a median age of 44 years (range, 19-68 years). Indication for treatment was DVT (n = 4), recurrent DVT (n = 1), stent thrombosis (n = 3), high-grade extrinsic narrowing of the inferior vena cava (IVC) due to immunoglobulin G4-related disease (n = 1), and IVC obstruction from liver tumor invasion (n = 1). Five patients had underlying May-Thurner syndrome. Five patients had iliofemoral involvement, two iliocaval, and one iliac vein alone. Two patients had central DVT, one of them involving the IVC and one involving the superior vena cava with brachiocephalic extension. Aspiration thrombectomy was technically successful in a total of six patients. Success was achieved in five of eight patients as the initial or main treatment modality and as an adjunctive treatment in one of two patients. Of the four patients in whom aspiration thrombectomy was not successful, three underwent successful further treatment with CDT. Recurrence after successful aspiration was seen in two patients. One patient developed pulmonary embolism that required no additional treatment. One patient experienced severe headaches treated with oral analgesics.

CONCLUSIONS

We observed a technical success of 60% for acute iliofemoral and central DVT with an aspiration thrombectomy system that allowed definitive treatment in one setting. As a novel therapy, this avoided the need for thrombolysis in the majority of selected cases with no bleeding complications and is a promising technique for acute DVT management.