Percutaneous recanalization of acutely thrombosed vessels by hydrodynamic thrombectomy (Hydrolyser)

Initial experience of thrombectomy using vascular snare with multiple loops for chronic organized thrombi in patients with thrombosed native hemodialysis fistulas

BACKGROUND

Thrombi in native hemodialysis access frequently exhibit chronic organized feature because they have formed over a long period. Removal of these is quite difficult owing to relatively large volume, resilient feature, limitations of the introducer sheath size, etc. In this study, we report our experience using a vascular snare for the removal of these thrombi in native arteriovenous fistula (AVF).

MATERIALS AND METHODS

The medical records of patients who underwent recanalization for thrombosed AVFs from January 2019 to August 2023 were reviewed. During the study period, a total of 29 native fistulas (19 brachiocephalic, nine radiocephalic, and one radiobasilic) in 25 patients were treated using a vascular snare with multiple loops (19 men and six women). Characteristics of the AVFs, endovascular procedures, technical and clinical results, and complications were evaluated.

RESULTS

Anatomic and clinical success rates were 96.6% and 100%, respectively. Total thrombosis was observed in 21 (72.4%) fistulas. Aneurysmal changes were found in 22 (75.9%) fistulas. The mean fistula age at the time of the procedure was 60.9 months (standard deviation, 52.2). Thrombectomy was initiated using a vascular snare in 14 fistulas. In 15 fistulas for which the procedures were initiated using a rotational percutaneous thrombectomy device (PTD), a vascular snare was subsequently used because recanalization failed or was insufficient due to chronic organizing thrombi. Additional aspiration and balloon angioplasty were performed in 27 (93.1%) and 28 (96.6%), respectively. Pharmacological thrombolysis was performed in one fistula for long segmental thrombosis combined with arterial thrombosis. The mean procedure time, excluding thrombolysis, was 91.9 min (standard deviation, 55.5). No complications related to the use of the vascular snare was observed.

CONCLUSION

The use of a vascular snare with multiple loops was safe and highly effective for the removal of chronic organized thrombi in the recanalization of thrombosed AVFs.

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.

The Hydrolyser Thrombectomy Catheter: A Single-Center Experience

Purpose:

To present a single-center experience with a mechanical hydrodynamic thrombectomy system (Hydrolyser) in native arteries, veins, and bypass grafts.

Methods:

The Hydrolyser is a 7F, double lumen, over-the-wire thrombectomy catheter. The device was used in 41 patients (22 males; mean age 68 years, range 40 to 90), with recent thromboses (aged 1 to 30 days, mean 8.7 ± 8.5), measuring from 4 to 35 cm long (mean 17.7 ± 9.5). The occlusions were located in native lower limb arteries (n = 28), bypass grafts (n = 8), superior venae cavae (n = 2), axillary vein (n = 1), and pulmonary arteries (n = 2).

Results:

Immediate technical success (residual clot < 50% of lumen diameter) was achieved in 34 patients (83%): 22/28 native arteries (78%), 7/8 bypass grafts (87%), and all pulmonary arteries, superior venae cavae, and the axillary vein. The 7 failed patients were treated surgically (bypass graft or Fogarty balloon). Adjunctive procedures were used to maximize luminal diameter: angioplasty (n = 29, with 13 immediate stent implantations), thromboaspiration (n = 17), and thrombolysis (n = 10). One case of distal embolism was the only complication (treated by thromboaspiration). At 30 days, 30 (73%) vessels remained patent.

Conclusions:

The Hydrolyser system is a promising concept for percutaneous thrombectomy. It is a quick, reliable, efficient device that may offer an alternative to thrombolysis and surgical thrombectomy.

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.

Endovascular recanalisation of an acute superior mesenteric artery occlusion. A case report and review of the literature

Introduction

Acute mesenteric ischaemia (AMI) continues to have a high mortality, ranging from 60 to 80%.

Presentation of case

A 78-year-old male presented with a 20-hour history of abdominal pain, secondary to a superior mesenteric artery (SMA) thromboembolic occlusion diagnosed on computed tomography (CT) angiography. Following confirmation of bowel viability at laparotomy, endovascular intervention using combined thrombolysis, angioplasty and thromboaspiration was performed. Despite successful recanalisation of the occlusion, his condition continued to deteriorate fatally due to progressive sepsis.

Discussion

We discuss the role of biphasic CT in diagnosis of AMI, and review the evidence for endovascular interventions now increasingly used in the emergent management of thromboembolic AMI.

Conclusion

Early diagnosis using CT angiography is essential, as it is highly sensitive in detecting a visceral arterial occlusion. However, laparotomy is often required to accurately determine bowel viability and the need for resection. Endovascular interventions appear to be effective alternatives to open surgery with appropriate patient selection.

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Early diagnosis by CT angiography is essential in acute mesenteric ischaemia.

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CT is limited in detecting non-specific secondary signs of bowel ischaemia.

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Endovascular interventions are safe alternatives to surgical revascularisation.

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Laparotomy is often required to determine bowel viability and need for resection.

Recanalization of thrombosed arteriovenous fistulas for hemodialysis by minimal venotomy

The present work describes the preliminary results of a new method of minimally invasive thrombectomy in the treatment of thrombosed arteriovenous fistula (AVF) with dilated aneurysm. Data from 25 patients who were treated with this minimal venotomy technique were retrospectively reviewed. The minimal venotomy was made on the dilated fistula, and thrombectomy was performed with forceps and Fogarty catheters through the venotomy site. Technical and clinical success was achieved in all 25 patients. There were two major and two minor complications (8% each). The two major complications consisted of bleeding at the venotomy site after early suture removal.

Percutaneous mechanical thrombectomy of superior mesenteric artery embolism

Background

The present series present three consecutive cases of successful percutaneous mechanical embolectomy in acute superior mesenteric artery ischemia. Superior mesenteric artery embolism is a rare abdominal emergency that commonly leads to bowel infarction and has a very high mortality rate. Prompt recognition and treatment are crucial for successful outcome. Endovascular therapeutic approach in patients with acute SMA embolism in median portion of its stem is proposed.

Case reports.

Three male patients had experienced a sudden abdominal pain and acute superior mesenteric artery embolism in median portion of its stem was revealed on computed tomography angiography. No signs of intestinal infarction were present. The decision for endovascular treatment was made in concordance with the surgeons. In one patient 6 French gauge Rotarex^® device was used while in others 6 French gauge Aspirex^® device were used. All patients experienced sudden relief of pain after the procedure with no signs of intestinal infarction. Minor procedural complication – rupture of a smaller branch of SMA during Aspirex^® treatment was successfully managed by coiling while transient paralytic ileus presented in one patient resolved spontaneously. All three patients remained symptom-free with patent superior mesenteric artery during the follow-up period.

Conclusions

Percutaneous mechanical thrombectomy seems to be a rapid and effective treatment of acute superior mesenteric artery embolism in median portion of its stem in absence of bowel necrosis. Follow-up of our patients showed excellent short- and long-term results.

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.

Percutaneous Laser-Facilitated Thrombectomy: An Innovative, Easily Applied, and Effective Therapeutic Option for Recanalization of Acute and Subacute Thrombotic Hemodialysis Shunt Occlusions

PURPOSE

To report our experience with excimer laser-facilitated recanalization of acute and subacute thrombotic occlusions of hemodialysis shunts.

METHODS

Twenty-one patients (16 women; mean age 54+/-19 years, range 31-76) presented with acute and subacute thrombotic occlusions of their hemodialysis shunts (4 Cimino, 17 prosthetic; 18 forearm, 3 upper arm); mean occlusion time was 4.1+/-3 days (range 1-14), and the thrombotic occlusion measured a mean 17.4+/-9 cm (range 5-27). Fresh thrombus was observed in addition to the total shunt occlusion in all cases. All patients were treated initially with a pulsed ultraviolet (308-nm) excimer laser. Eighteen (85.7%) patients received adjunctive local thrombolysis for treatment of residual thrombus. Nineteen (90.5%) patients underwent angioplasty of the underlying anastomotic stenosis.

RESULTS

The angiographic occlusion was reduced from 100% to 63%+/-28% after laser treatment and to 36%+/-18% after 1 hour of thrombolytic therapy (20 mg tissue plasminogen activator). TIMI flow increased significantly from grade 0 to 2.7+/-0.5 following laser ablation (p<0.001) and to 3.0+/-0.2 upon completion of the angioplasty procedure (p>0.001 versus baseline). The immediate procedural success was 95.2% (20/21). Detectable thrombotic embolization and laser-related complications were not observed in any case. Primary patency was 85%; 3 patients had abnormal Doppler flow within 6 weeks and underwent reintervention (secondary patency 100%). All successfully treated shunts were usable for further dialysis at the 6-week follow-up.

CONCLUSION

Percutaneous excimer laser-facilitated thrombus vaporization is safe and effective for recanalization of acute and subacute thrombotic occlusions of hemodialysis shunts.

Recanalization of acute and subacute femoropopliteal artery occlusions with the rotarex catheter: one year follow-up, single center experience

PURPOSE

To assess the efficacy and safety of a new rotational catheter for percutaneous removal of fresh and organized thrombi in the femoropopliteal artery.

METHODS

Forty-one limbs in 38 patients (age 56--90 years, mean 75.6 years) with acute, subacute or chronic femoropopliteal occlusions of 1--180 days' duration (mean 31.6 days) were treated with the Rotarex device. The Fontaine stage was mainly IIB (Rutherford 2--3, 22 patients) or III (Rutherford 4, 14 patients). The length of occlusion varied from 2 to 35 cm (mean 13.1 cm). After recanalization percutaneous transluminal angioplasty (PTA) was performed if there was a residual stenosis of >25%. Patients were followed up with color Doppler ultrasound at 48 hr and clinically with Doppler pressures and oscillometry at 3, 6, and 12 months.

RESULTS

After an average of two passages with the Rotarex catheter all but two limbs required PTA for residual stenosis >25%. Five patients needed additional stenting. Major complications were one groin hematoma requiring blood transfusion and one arteriovenous fistula spontaneously thrombosing after unsuccessful primary prolonged balloon dilation. Distal embolizations occurred in 10 patients; 6 clinically relevant emboli were aspirated. All occlusions were technically successfully recanalised there were 2 early reocclusions after 1 day and two at 2 weeks. Brachial-ankle indices improved from an average of 0.41 before to 0.93 after recanalization. Primary and secondary patency rates were 62% / 84% after 6 months and 39% / 68% after 1 year. The amputation-free survival at 12 months was 100%.

CONCLUSION

The Rotarex mechanical thrombectomy device is an efficient, quick, easy to handle, and safe tool for the treatment of acute, subacute or even chronic peripheral arterial thromboembolic occlusions. It can be used for short or long occlusions with equal success, provided the obstruction is not heavily calcified and has been safely passed with a guidewire first.

Mechanical thrombectomy of occluded hemodialysis native fistulas and grafts using a hydrodynamic thrombectomy catheter: preliminary experience

The purpose of this study was to evaluate the efficacy and safety of a new hydrodynamic percutaneous thrombectomy catheter in the treatment of thrombosed hemodialysis fistulas and grafts. Twenty-two patients (median age: 47 years; range: 31-79 years) underwent mechanical thrombectomy for thrombosed hemodialysis fistulas or polytetrafluoroethylene (PTFE) grafts. In all cases, an Oasis hydrodynamic catheter was used. Five patients had native fistulas and 17 had PTFE grafts. Six patients required repeat procedures. All patients with native fistulas and 15 of the 17 with PTFE grafts also underwent angioplasty of the venous limb following the thrombectomy. Major outcome measures included technical success, clinical success, primary and secondary patency, and complication rates. Twenty-eight procedures were performed in total. The technical success rate was 100% and 90% and clinical success was 86% and 76% for native fistulas and grafts, respectively. The primary patency at 6 months was 50% and 59% for fistulas and grafts, respectively, and the secondary patency at 6 months was 75% and 70% for fistulas and grafts, respectively. Two patients died of unrelated causes during the follow-up period. The Oasis catheter is an effective mechanical device for the percutaneous treatment of thrombosed hemodialysis access. Our initial success rate showed that the technique is safe in the treatment of both native fistulas and grafts.

Vascular injury caused by mechanical thrombectomy in porcine arteries: AKónya eliminator device versus Arrow-Trerotola percutaneous thrombolytic device

PURPOSE

To compare vascular injuries induced by a nonrotational thrombectomy device equipped with an adjustable basket (the AKónya Eliminator [AKE] device) and the Arrow-Trerotola percutaneous thrombolytic device (PTD) in porcine external iliac arteries (EIAs).

MATERIALS AND METHODS

The EIAs of nine domestic pigs underwent simulated thrombectomy with the AKE after the diameter of the basket had been adjusted to the vessel's diameter and with the PTD after motor activation. Three animals were euthanized immediately after treatment (group 1, acute), three after 1 week (group 2, subchronic), and three after 6 weeks (group 3, chronic). Vessel diameters were measured angiographically at four anatomic locations at the three time points. A histologic grading system was established to quantify the degree of vascular injury and lumen compromise. Four other EIAs were treated with an "oversized" AKE basket and followed for 6 weeks.

RESULTS

Histologically, the acute lesions in the AKE-treated vessels were more superficial than those in the PTD-treated vessels. In group 2, two of three PTD-treated arteries occluded, and their subchronic injuries were more serious than those in the AKE-treated arteries. In group 3, all AKE-treated arteries remained patent, but one of the PTD-treated vessels occluded, and the lumen sizes of the PTD- and AKE-treated arteries differed significantly. After 6 weeks, there was no significant difference between arteries treated with the PTD and those treated with the oversized AKE in terms of diameter or histologic grading.

CONCLUSIONS

The adjustable basket and hand-controlled operation of the AKE were significantly less injurious to the arterial wall than the constant-size PTD basket operated at 3,000 rpm. Damage produced by the oversized AKE basket was similar to that produced by the PTD.

Transradial intervention for native fistula failure

The native radiocephalic (Brescia-Cimino) fistula is usually constructed with an anastomosis of the cephalic vein and radial artery. Catheter interventions for native fistula failure have until now been performed via the transcephalic or transbrachial approach. Transradial intervention for native fistula failure was prospectively evaluated for a selected consecutive 11 patients. Six patients had a single lesion and 5 patients had double lesions. Twelve lesions were stenotic and 4 were occlusive with thrombus. Balloon angioplasty alone was successful in 10 lesions. In thrombosed fistulas, 2 lesions underwent manual catheter-directed thrombo-aspiration and 2 further lesions underwent a combination of catheter-directed thrombo-aspiration and mechanical thrombectomy. Cutting Balloon angioplasty was performed for 3 resistant venous stenoses and for 1 radial artery stenosis. Technical and clinical success were achieved in all patients. No vessel rupture or perforation was observed in this study, nor was distal embolization in the radial artery or symptomatic pulmonary embolism. No radial artery occlusion or fistula infection was seen during the follow-up. The primary patency rates were 82% at 3 months and 64% at 6 months. Transradial intervention for native fistula failure is considered safe and feasible in a selected population; yet requires further validation.

Interventions in Infrainguinal Bypass Grafts

The interventional radiologist plays an important role in the detection and prevention of infrainguinal bypass failure. Early detection and evaluation of flow-limiting lesions effectively preserve graft (venous bypass and polyester or expanded polytetrafluoroethylene bypass) patency by identifying stenoses before occlusion occurs. Delay in treatment of the at-risk graft may result in graft failure and a reduced chance of successful revascularization. For this reason, surveillance protocols form an important part of follow-up after infrainguinal bypass surgery. As well as having an understanding of the application of imaging techniques including ultrasound, MR angiography, CT angiography and digital subtraction angiography, the interventional radiologist should have detailed knowledge of the minimally invasive therapeutic options. Percutaneous transluminal angioplasty (PTA), or alternatively cutting balloon angioplasty, is the interventional treatment of choice in prevention of graft failure and occlusion. Further alternatives include metallic stent placement, fibrinolysis, and mechanical thrombectomy. Primary assisted patency rates following PTA can be up to 65% at 5 years. When the endovascular approach is unsuccessful, these therapeutic options are complemented by surgical procedures including vein patch revision, jump grafting, or placement of a new graft.

Acute superior mesenteric artery embolism: rapid reperfusion with hydrodynamic thrombectomy and pharmacological thrombolysis

PURPOSE

To report a case of acute superior mesenteric artery (SMA) embolism successfully treated with hydrodynamic thrombectomy and pharmacological thrombolysis.

CASE REPORT

A 67-year-old man was admitted to the hospital with acute severe abdominal pain. Selective angiography via a femoral puncture revealed a complete embolic occlusion distal to the first jejunal branch of the SMA. Hydrodynamic thrombectomy resolved the severe abdominal pain of the patient in approximately 10 minutes after the start of thrombectomy. Local continuous thrombolysis with urokinase resulted in near complete restoration of the mesenteric flow after 24 hours. The patient made an uneventful recovery and continues to do well on warfarin therapy 8 months after treatment; he has shown no evidence of malabsorption.

CONCLUSIONS

Although insertion of the device into the SMA via a femoral puncture is a difficult approach, we propose that hydrodynamic thrombectomy followed by local thrombolysis is a useful treatment for acute superior mesenteric artery embolism.

Dilatation and declotting of arteriovenous accesses

The autogenous arteriovenous fistula has long been proven to be the most durable access for hemodialysis and therefore for any therapy based on plasma exchange. Forearm autogenous fistulas are, however, frequently challenging to create, leading less experienced surgeons to create elbow fistulas or even worse, to place prosthetic grafts. Once the arteriovenous access is constructed, stenoses largely located on the venous side frequently occur, leading to thrombosis if they are not detected and preventively treated. Interventional radiology is now the first line and preferred treatment in the majority of cases of vascular access dysfunction. The overall advantages compared with conventional surgery are its minimal invasiveness, better preservation of the patient's venous reserve, and better outcomes for selected indications such as thrombosed autogenous fistulas. Prophylactic dilation of stenoses greater than 50% associated with clinical abnormalities such as flow-rate reduction is warranted to prolong access patency. Stents are placed only in selected cases with clearly insufficient results of dilation but they must never overlap major side veins and obviate future access creation. Thrombosed fistulas and grafts can be declotted by purely mechanical methods or in combination with a lytic drug. The success rates are over 90% for dilation, in central veins radiologists frequently resort to the use of stents. Long-term results after dilation in the largest series are better in forearm native fistulas compared with grafts. The initial success rates for declotting are better in grafts compared with forearm fistulas but early rethrombosis is frequent in grafts so that primary patency rates can be better for native fistulas from the first month's follow-up.

Early experience with a rotational thrombectomy device for treatment of acute and subacute infra-aortic arterial occlusions

PURPOSE

To evaluate a rotational thrombectomy device in the treatment of acute and subacute/chronic thrombotic infra-aortic occlusions of native vessels and bypass grafts.

METHODS

From July 2000 to February 2002, 98 patients (65 men; mean age 66+/-9 years, range 47-90) with 100 thrombotic occlusions (mean age of occlusion 31+/-33 days, range 0-140) measuring an average of 21+/-11 cm long (range 2-40) were treated with rotational thrombectomy (Rotarex). There were 33 acute (</=14 days) thrombotic/embolic native artery occlusions (group I), 58 subacute/chronic (>14 days) native artery occlusions (group II), and 9 acute bypass graft occlusions (group III).

RESULTS

The device activation time was 4.9+/-1.4 minutes, during which 4.0+/-1.4 passes of the device were performed. The amount of aspirated fluid was 240+/-119 mL. Slightly less than half the arteries (48%) were stented. Primary success (residual stenosis <30%) was achieved in 92% (94% for group I, 93% for group II, and 78% for group III; 100% for the ipsilateral approach, 56% for the crossover approach). Among the 18 complications, 3 were serious (2 amputations after unsuccessful intervention and 1 death); there were 8 vessel perforations and 7 cases of peripheral embolization. Thirty-day survival and limb salvage was 88% for group I, 100% for group II, and 66% for group III.

CONCLUSIONS

The device is an easy-to-handle, useful tool for ipsilateral treatment of acute and subacute thrombotic arterial and bypass graft occlusions. The use of this device is limited by the 8-F diameter of the catheter and the limited capacity for crossover interventions.

Peripheral arterial applications of percutaneous mechanical thrombectomy

Various devices have been introduced for the purpose of percutaneous mechanical thrombectomy (PMT). These devices show promise as a valuable treatment option in acute arterial thrombotic occlusions, in addition to the gold-standard surgical method, the Fogarty balloon embolectomy, and local fibrinolysis therapy. Local fibrinolytic therapy cannot be used in the presence of contraindications, and can be time-consuming in limb threatening situations. Surgical intervention can also result in intimal vessel wall injury and is of limited value in infrageniculate occlusions. In this review, currently available PMT devices for peripheral arterial applications will be introduced, and their advantages, drawbacks and finally the reported clinical experience with these devices will be presented.

Application of percutaneous mechanical thrombectomy in autogenous fistulae

Articles proving that the majority of thrombosed autogenous fistulae can be recovered by interventional radiology are relatively recent, and the largest series to date have favored mechanical methods including manual catheter-directed aspiration, the Hydrolyzer, Amplatz Thrombectomy device, Arrow-Trerotola device, and the rotating pigtail. Rare contraindications to declotting include infection, fistula immaturity, and large aneurysms. The success rates range from 76% to 100% and compare well with the surgical approach whose effectiveness is not supported by comparable publications. The technical challenges of this outpatient procedure can include difficulties in initial catheterization of the vein or in crossing tight stenosis and actual removal of large thrombi. Although more challenging to declot than grafts, forearm autogenous fistulae are more rewarding. Better long-term patency has been achieved in the largest series to date as long as the underlying stenoses are sufficiently dilated (50% 1-year primary and 80% secondary patency rates). The results reported in the upper arm are less good. The unmasking of stenoses in close to 100% of cases warrants stenosis detection programs similar to those for grafts.

Manual catheter-directed aspiration and other thrombectomy techniques for declotting native fistulas for hemodialysis

Recent articles reported excellent results in the percutaneous declotting of native fistulas for hemodialysis with use of thromboaspiration, mechanical devices, or thrombolytic drugs, with success rates ranging from 76% to 100%. These results challenge the surgical approach, the effectiveness of which is not supported by comparable publications. Although it is more difficult to declot forearm native fistulas than grafts, declotting of fistulas is more rewarding because it achieves better long-term patency (1-year primary rates as high as 50% and secondary rates of 80%). The results reported from declotting of fistulas in the upper arm are not as good. The unmasking of stenoses in close to 100% of cases warrants stenosis detection programs similar to those used for grafts.

Hydrodynamic thrombectomy system versus pulse-spray thrombolysis for thrombosed hemodialysis grafts: a multicenter prospective randomized comparison

PURPOSE

To evaluate the safety and efficacy of a hydrodynamic thrombectomy system in a prospective, multicenter randomized comparison with pulse-spray thrombolysis in hemodialysis grafts.

MATERIALS AND METHODS

Nine centers enrolled 120 adult patients with recently (</=14 days) thrombosed hemodialysis grafts. Graft venography was used to confirm occlusion in 62 patients randomly assigned to thrombectomy and 58 to thrombolysis. For thrombolysis, a mixture of 5,000 U of heparin and 250,000 U of urokinase was distributed throughout the thrombus, first to the venous then to the arterial graft end. For thrombectomy, the catheter was passed in the same sequence. Technical success was removal of 80% or more of thrombus. Clinical success was technical success plus the ability to dialyze. Also assessed were total procedure time, thrombus treatment time, procedure-related blood loss, other complications, and 30- and 90-day outcomes.

RESULTS

Patient demographics were comparable. Technical success rates were 95% (59 of 62) for thrombectomy and 90% (52 of 58) for thrombolysis (P: =.31). Clinical success rates were 89% (55 of 62) and 81% (47 of 58), respectively (P: =.24). At 30 days, 69% (43 of 62) and 66% (38 of 58), respectively, could be dialyzed through the graft (P: =.70); at 90 days, the rates were 40% (25 of 62) and 41% (24 of 58), respectively (P: =.91). None of these differences or those for procedure-related blood loss and early and late complications were statistically significant. Thrombus treatment times of 16.8 minutes for thrombectomy and 23.4 minutes for thrombolysis were significantly different (P: <.01).

CONCLUSION

The hydrodynamic thrombectomy system is at least as efficacious and safe as pulse-spray thrombolysis but shortens thrombus treatment time.

Mechanical thrombolysis of thrombosed hemodialysis native fistulas with use of the Arrow-Trerotola percutaneous thrombolytic device: our preliminary experience

PURPOSE

To evaluate the feasibility of use of the Arrow-Trerotola percutaneous thrombolytic device (PTD) in the treatment of thrombosed hemodialysis native fistula occlusions.

MATERIALS AND METHODS

Ten patients with native fistula occlusion underwent mechanical thrombolysis with use of the PTD. The standard PTD was used in seven patients and the over-the-wire device was used in three patients. Major outcomes of our study included procedure time, clinical success, complication rate, and 3- and 6-month patency rates.

RESULTS

The technical success rate was 100% and the clinical success rate was 90% (9 of 10). In all 10 cases, the procedure was associated with angioplasty. There were no major complications. The mean time of successful procedures was 126.1 minutes. The 3- and 6-month primary patency rates were 70% and 60%, respectively; the assisted primary patency rate at 6 months was 80%.

CONCLUSION

The PTD is an effective mechanical device for percutaneous treatment of thrombosed hemodialysis access. Our clinically successful initial experience with the PTD shows that the technique is rapid and safe for treatment of native fistula occlusions.

Treatment of failed native arteriovenous fistulae for hemodialysis by interventional radiology

BACKGROUND

We studied the feasibility, technical problems, safety, and effectiveness of percutaneous declotting of thrombosed native arteriovenous fistulae for hemodialysis.

METHODS

Between 1992 and 1998, 93 declotting procedures were performed in 73 consecutive upper limb native fistulae (forearm 56 and upper arm 17), and 162 procedures were performed in 78 prosthetic grafts using manual catheter-directed thrombo-aspiration, with or without previous urokinase infusion. Detection of restenosis by clinical surveillance led to redilation or stent placement. Rethrombosis in four forearm and six upper arm fistulae were treated by 20 further declottings by aspiration.

RESULTS

The initial success was 93% in the forearm and 76% in the upper arm (99% in grafts). The complications included one pulmonary embolism, one acute pseudoaneurysm, and one blood depletion requiring transfusion. Primary patency rates at one year were 49% in the forearm and 9% in the upper arm (14% in grafts). Secondary patency rates were 81 and 50% at one year, respectively (83% in grafts). Reinterventions were necessary every 19.6 months in the forearm and every 5.7 months in the upper arm (every 6.4 months in grafts, P < 0.05). Stents were placed in 11% of forearm fistulae and in 41% of upper arm fistulae (45% of grafts) for treatment of acute rupture (5 out of 19), stenosis recoil (6 out of 19), and early (< 6 months) recurring stenosis (8 out of 19).

CONCLUSIONS

The percutaneous declotting of forearm fistulae by manual catheter-directed thrombo-aspiration was effective in more than 90% of cases and yielded 50% primary and 80% secondary patency rates at one year. The results were poorer in upper arm fistulae. The need for maintenance reinterventions was three times smaller in forearm fistulae than in upper arm fistulae and grafts.

Rheolytic hydrodynamic thrombectomy for percutaneous treatment of acutely occluded infra-aortic native arteries and bypass grafts: midterm follow-up results

RATIONALE AND OBJECTIVES

To evaluate the efficacy of a rheolytic thrombectomy catheter (RTC) for treatment of acutely occluded infra-aortic native arteries and bypass grafts and to determine midterm primary patency, death, and amputation-free survival rates.

METHODS

From March 1995 to September 1997, 112 patients with occluded arteries or bypass grafts were primarily treated with RTC at two centers. Thrombus removal was evaluated by two angiographers.

RESULTS

More than 75% of the thromboembolic material could be removed with RTC alone. Mean activation time of RTC was 280 +/- 163 seconds. Residual mural or organized thrombi (29%) required adjunctive fibrinolytic therapy or aspiration thrombectomy. Remaining stenoses were treated with percutaneous transluminal angioplasty and additional stent implantation. For acute reocclusions, surgical intervention was required. Technical success after the entire procedure was 88.4%. RTC-associated complications included distal embolization, dissection, vessel perforation, and technical failure of RTC. Mean follow-up time was 14.8 months +/- 11.5, rates of primary patency, secondary patency, death, and amputation-free survival were 60%, 84%, 16%, and 75% after 2 years, respectively.

CONCLUSIONS

RTC is a rapid and efficient technique for mechanical thrombectomy of acutely thrombosed native leg arteries and bypass grafts. Midterm results are comparable to the results of alternative treatment modalities such as Fogarty balloon thromboembolectomy or local fibrinolysis.

In vitro effectiveness study for hydrodynamic thrombectomy devices of the second generation

RATIONALE AND OBJECTIVES

To determine the efficacy of clot removal and the amount of applied saline and aspirated fluid and to compare procedure-related particle embolization for the hydrodynamic thrombectomy devices the LF 140 Angiojet (LF 140), the double-lumen Hydrolyser (double HL), and the triple-lumen Hydrolyser (triple HL) in an in vitro flow model.

METHODS

Thrombectomy of clots (n = 42) from 7-day-old porcine blood (9.8 g) was performed with the LF 140, the double HL, and the triple HL in a flow model (flow 1 L/min) made of silicone tubes (7 mm inner tube diameter). All catheters were used according to the manufacturer's recommendations.

RESULTS

Mean time of thrombectomy ranged from 20 seconds (triple HL) to 58 seconds (LF 140, P < 0.05). Only for the triple HL was remaining thrombus found within the tubes (41 mg). None of the tested devices worked isovolumetrically: the mean ratio of applied saline and aspirated fluid for the devices ranged from 0.79 (triple HL) to 0.89 (double HL, P < 0.05). Mean embolus weight and percentage of embolism from original thrombus were 675 mg/6.7% (LF 140, P < 0.05), 38 mg/0.4% (double HL), and 26 mg/0.3% (triple HL).

CONCLUSIONS

Thrombectomy time and embolus weight depend on the device chosen. The ratio of applied to aspirated fluid, indicating the capability to work nearly isovolumetrically, is acceptable for all tested devices. In vitro, the triple HL seems to be the most appropriate device for rapid mechanical, hydrodynamic thrombectomy. Because of the high in vitro particle embolization rate, the LF 140 seems to be strictly limited to small-caliber vessels.

The Hydrolyser thrombectomy catheter: a single-center experience

PURPOSE

To present a single-center experience with a mechanical hydrodynamic thrombectomy system (Hydrolyser) in native arteries, veins, and bypass grafts.

METHODS

The Hydrolyser is a 7F, double lumen, over-the-wire thrombectomy catheter. The device was used in 41 patients (22 males; mean age 68 years, range 40 to 90), with recent thromboses (aged 1 to 30 days, mean 8.7+/-8.5), measuring from 4 to 35 cm long (mean 17.7+/-9.5). The occlusions were located in native lower limb arteries (n = 28), bypass grafts (n = 8), superior venae cavae (n = 2), axillary vein (n = 1), and pulmonary arteries (n = 2).

RESULTS

Immediate technical success (residual clot < 50% of lumen diameter) was achieved in 34 patients (83%): 22/28 native arteries (78%), 7/8 bypass grafts (87%), and all pulmonary arteries, superior venae cavae, and the axillary vein. The 7 failed patients were treated surgically (bypass graft or Fogarty balloon). Adjunctive procedureswere used to maximize luminal diameter: angioplasty (n = 29, with 13 immediate stent implantations), thromboaspiration (n = 17), and thrombolysis (n = 10). One case of distal embolism was the only complication (treated by thromboaspiration). At 30 days, 30 (73%) vessels remained patent.

CONCLUSIONS

The Hydrolyser system is a promising concept for percutaneous thrombectomy. It is a quick, reliable, efficient device that may offer an alternative to thrombolysis and surgical thrombectomy.