Current status of percutaneous mechanical thrombectomy. Part III. Present and future applications

Midterm Results of Drug-Coated Balloon Alone or Combined with Rotarex Thrombectomy Device for Treatment of Subacute Femoropopliteal Artery Thrombotic Occlusion

BACKGROUND

This retrospective multicenter study aimed to compare the midterm results of the Rotarex rotational thrombectomy device combined with drug-coated balloon (DCB) and DCB-alone for the treatment of subacute femoropopliteal artery thrombotic occlusion.

METHODS

All patients (74, aged 70.1 ± 9.3 years) were nonrandomized and divided into 2 groups based on treatment strategy between 2018 and 2020. Intraoperative technical success (defined as <30% residual stenosis), dissection types and bailout-stenting rates were assessed. Ankle-brachial index (ABI), primary patency (PP, restenosis <50%) and freedom from clinically driven target lesion reintervention (CD-TLR) were documented at follow-up.

RESULTS

Among them, 35 patients were treated with the Rotarex catheter combined with DCB while 39 patients underwent DCB-alone. The-overall technical success rate was 100%. Patients in the Rotarex + DCB group showed lower rate of bailout stenting than those in the DCB alone group (22.9% vs. 59.0%; P = 0.01). ABI at discharge was significantly higher in both groups. Mean follow-up time was 18.5 ± 3.4 months; 62 patients completed Doppler ultrasound investigation while 12 patients were censored. According to Kaplan-Meier analysis, the estimated PP was 82.0 ± 6.7% in the Rotarex + DCB group, whereas a significantly lower rate in the DCB alone group (60.9 ± 8.3%, P = 0.04). In addition, the freedom from CD-TLR rate was 82.9 ± 6.4% in the Rotarex + DCB group and 61.5 ± 7.8% in the DCB-alone group (P = 0.04).

CONCLUSIONS

These initial data indicate that the Rotarex thrombectomy device combined with DCB is an effective choice for the treatment of subacute femoropopliteal artery thrombotic occlusion compared to DCB-alone. The combined procedure had superior midterm results.

Recanalization of acute and subacute venous and synthetic bypass-graft occlusions with a mechanical rotational catheter

PURPOSE

Percutaneous mechanical thrombectomy (PMT) is now established as an alternative treatment of acute arterial occlusions in addition to fibrinolysis and surgical thrombectomy. The objective of this retrospective study was the investigation of a rotational atherothrombectomy catheter in terms of safety and efficacy in the treatment of acute and subacute femoropopliteal bypass occlusions.

MATERIALS AND METHODS

Forty-two patients (average age 65.8 ± 9.1 years) with acute (<14 days [n = 31]) and subacute (14-42 days [n = 11]) femoropopliteal bypass occlusions were treated consecutively with a rotational debulking and removal catheter (Straub Rotarex). The average occlusion length was 28.4 ± 2.9 (24-34) cm. Thirty-four (81%) patients underwent venous bypass, and 8 (19%) patients underwent polytetrafluoroethylene bypass.

RESULTS

The technical success rate was 97.6% (41 of 42). In 1 patient, blood flow could not be restored despite the use of the atherothrombectomy system. The average catheter intervention time was 6.9 ± 2.1 (4-9) min. Ankle-brachial index increased from 0.39 ± 0.13 to 0.83 ± 0.11 at discharge and to 0.82 ± 0.17 after 1 month (p < 0.05). There were a total of 2 (4.8%) peri-interventional complications: One patient developed a distal embolism, which was successfully treated with local lysis, and another patient had a small perforation at the distal anastomosis, which was successfully treated with a stent.

CONCLUSION

PMT with the Rotarex atherothrombectomy catheter represents a safe and effective option in the treatment of acute and subacute femoropopliteal bypass occlusions because it can quickly restore blood flow.

Recanalisation of thrombotic arterial occlusions with rotational thrombectomy

PURPOSE

This study sought to assess the effectiveness of rotational thrombectomy (RT) with the Rotarex device in the treatment of thrombotic occlusions in native arteries, by-pass grafts, stents and stent-grafts.

MATERIALS AND METHODS

Over the last 4 years, 22 patients (14 men and 8 women; mean age 62.6 years) affected by 5 acute (<14 days) thrombotic occlusions of the native arteries (4 plaque thromboses in the common iliac artery and one on a dissection intimal flap of the external iliac artery), 17 subacute and chronic thromboses affecting 4 femoro-popliteal by-pass grafts, 10 stents (7 in the common iliac artery and 3 in the superficial femoral artery) and 3 stents-grafts were studied. Acute thromboses of native arteries were follow-up with colour-Doppler ultrasound (US) examination at 1 and 3 months. Subacute and chronic thrombotic occlusions were follow-up with colour-Doppler US examination at 1, 3, 6 and 12 months and yearly thereafter.

RESULTS

Immediate technical success was achieved without any need for additional procedures in all acute occlusions of native arteries (4/22 cases). In the subacute and chronic occlusions, the procedure was completed with percutaneous transluminal angioplasty (PTA) (8/22), cutting balloon (6/22) and stenting (5/22). The complication rate was 4.8% (1 rupture of the external iliac artery repaired with a stent-graft).

CONCLUSIONS

Arterial recanalisation with RT is the treatment of choice for acute thrombosis of healthy native arteries (4-7 mm); the treatment of thrombosis complicating calcified plaques or dissection intimal flaps may cause rupture of the arterial wall. In subacute and chronic occlusions of by-pass grafts, stents and stent grafts, additional procedures are necessary to achieve complete recanalisation.

Catheter fragmentation of acute massive pulmonary thromboembolism: distal embolisation and pulmonary arterial pressure elevation

The aim of this study was to evaluate the relationship between pulmonary arterial pressure and distal embolisation during catheter fragmentation for the treatment of acute massive pulmonary thromboembolism with haemodynamic impairment. 25 patients with haemodynamic impairment (8 men and 17 women; aged 27-82 years) were treated by mechanical thrombus fragmentation with a modified rotating pigtail catheter. After thrombus fragmentation, all patients received local fibrinolytic therapy, followed by manual clot aspiration using a percutaneous transluminal coronary angioplasty (PTCA) guide catheter. Pulmonary arterial pressure was continuously recorded during the procedure. The Friedman test and Wilcoxon test were applied for statistical analysis. Distal embolisation was confirmed by digital subtraction angiography in 7 of the 25 patients. A significant rise in mean pulmonary arterial pressure occurred after thrombus fragmentation (before: 34.1 mmHg; after: 37.9 mmHg; p<0.05), and this group showed a significant decrease in mean pulmonary arterial pressure after thrombus aspiration (25.7 mmHg; p<0.05). No distal embolisation was seen in 18 of the 25 patients, and a significant decrease in mean pulmonary arterial pressure was confirmed after thrombus fragmentation (before: 34.2 mmHg; after: 28.1 mmHg: p<0.01), and after thrombus aspiration (23.3 mmHg; p<0.01). In conclusion, distal embolisation and a rise in pulmonary arterial pressure can occur during mechanical fragmentation using a rotating pigtail catheter for the treatment of life-threatening acute massive pulmonary thromboembolism; thrombolysis and thrombus aspiration can provide partial recanalization and haemodynamic stabilization. Continuous monitoring of pulmonary arterial pressure may contribute to the safety of these interventional procedures.

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.

Suction thrombectomy of thrombotic occlusion of the subclavian artery in a case of Takayasu's arteritis

Takayasu's arteritis, also known as pulseless disease, is a chronic inflammatory arteritis affecting large vessels, predominantly the aorta and its main branches. Vessel inflammation leads to wall thickening, fibrosis, stenosis, and thrombus formation. Percutaneous removal of arterial thrombus with the use of several devices has been reported, with mixed results. We present a case of Takayasu's arteritis with thrombotic occlusion of the subclavian artery in which pulsed urokinase injection and suction thrombectomy were used to revascularize a threatened limb and to establish the sole arterial supply to the brain.

Mechanical Thrombectomy of Acute Iliofemoral Deep Vein Thrombosis with Use of an Arrow-Trerotola Percutaneous Thrombectomy Device

PURPOSE

To evaluate the immediate and 1-year clinical outcomes of mechanical thrombectomy with use of the Arrow-Trerotola percutaneous thrombectomy device (PTD) with or without low-dose urokinase in the treatment of acute iliofemoral deep vein thrombosis (DVT).

MATERIALS AND METHODS

Mechanical thrombectomy with the PTD was performed in 25 patients with acute iliofemoral DVT. Thrombolytic therapy with low-dose urokinase was used in all patients without contraindications (n = 20). Other therapies used in combination included inferior vena cava filter insertion (n = 5), sheath aspiration thrombectomy (n = 25), and angioplasty and stent placement (n = 20).

RESULTS

Initial technical and clinical success was achieved in all cases. In the 20 patients who had no contraindications to the use of urokinase, the dosage of urokinase did not exceed 1 million IU (range, 360,000-1,000,000 IU; mean, 640,000 IU). The mean time of urokinase infusion was 16 hours (range, 12-20). In five patients who had a contraindication to the use of urokinase, mechanical thrombectomy with the PTD was successful without the use of urokinase. There were no major complications. Primary patency of the stent-implanted common iliac vein segment was achieved at 1 year in 17 of 20 patients (85%). The overall 1-year clinical success rate was 92% (23 of 25 patients). Valvular insufficiency occurred in two patients (8%).

CONCLUSION

The PTD is an effective mechanical thrombectomy device in the treatment of acute iliofemoral DVT with or without adjunctive urokinase thrombolysis.

The Case for Thrombolysis for Iliofemoral Venous Thrombosis

Deep venous thrombosis and its consequences remain a significant clinical challenge despite advances in the current healthcare system. The use of thrombolytic therapy has played an important role in the management of both arterial and venous thrombotic conditions. In this article, relevant clinical evidence and rationale in support of thrombolytic therapy in ileofemoral deep venous thrombosis are discussed.

Percutaneous Venous Thrombectomy Using the Arrow-Trerotola Percutaneous Thrombolytic Device (PTD) with Temporary Caval Filtration: In Vitro Investigations

PURPOSE

To evaluate the size and quantity of downstream emboli after thrombectomy using the Arrow-Trerotola Percutaneous Thrombolytic Device (PTD) with or without temporary filtration for extensive iliofemoral and iliocaval thrombi in an in vitro flow model.

METHODS

Iliocaval thrombi were simulated by clotted bovine blood in a flow model (semilucent silicone tubings, diameter 12-16 mm). Five experimental set-ups were performed 10 times each; thrombus particles and distribution were measured in the effluent. First, after retrograde insertion, mechanical thrombectomy was performed using the PTD alone. Then a modified self-expanding tulip-shaped temporary vena cava stent filter was inserted additionally at the beginning of each declotting procedure and removed immediately after the intervention without any manipulation within or at the filter itself. In a third step, the filter was filled with thrombus only. Here, two experiments were performed: Careful closure within the flow circuit without any additional fragmentation procedure and running the PTD within the filter lumen, respectively. In the final set-up, mechanical thrombectomy was performed within the thrombus-filled tubing as well as in the filter lumen. The latter was closed at the end of the procedure and both devices were removed from the flow circuit.

RESULTS

Running the PTD in the flow circuit without filter protection led to a fragmentation of 67.9% (+/-7.14%) of the clot into particles < or =500 microm; restoration of flow was established in all cases. Additional placement of the filter safely allowed maceration of 82.9% (+/-5.59%) of the thrombus. Controlled closure of the thrombus-filled filter within the flow circuit without additional mechanical treatment broke up 75.2% (+/-10.49%), while additional mechanical thrombectomy by running the PTD within the occluded filter led to dissolution of 90.4% (+/-3.99%) of the initial clot. In the final set-up, an overall fragmentation rate of 99.6% (+/-0.44%) was achieved.

CONCLUSIONS

The combined use of the Arrow-Trerotola PTD and a temporary vena cava stent filter proved to be effective for even large clot removal in this experimental set-up.

Venous thromboembolism in the intensive care unit

Most ICU patients have a significant number of risk factors for VTE. The high incidence of DVT in the ICU population and the recognition of a high incidence of PE at autopsy confirm this. We have alluded to the difficulty of clinical diagnosis of VTE and the need for diagnostic investigations. We have reviewed currently available diagnostic investigations with regard to their sensitivity and specificity and their practicability in ICU patients, and have formulated recommended diagnostic algorithms (Figs. 4 and 5). The most important factor in the management of VTE is prevention. In the ICU, all patients are at high risk for VTE, and therefore, at a minimum should receive subcutaneous prophylactic heparin unless it is contraindicated. Alternative methods of prophylaxis are available, and should be considered for patients who have contraindications to heparin.

Applications of percutaneous mechanical thrombectomy in pulmonary embolism

Percutaneous mechanical thrombectomy (PMT) has matured into a reliable and valuable therapeutic tool in acute vascular diseases. PMT devices are designed to achieve rapid clearance of acute occlusion in large arteries and veins. This article provides a summary of cumulated experience on pulmonary embolism (PE) treatment with PMT devices. PMT devices are a heterogeneous group of devices that uses different forms of energy. Most of the devices do not totally eliminate thrombus rather fragment in small particles. The rationale of PMT is based on the rapid relief of central pulmonary obstruction. PMT in massive PE provides efficacious and safe debulking of centrally located thrombus in PE, lowering pulmonary artery pressures and improving hemodynamics and blood oxygenation. This results in lowering mortality if compared with natural history of PE, and reduced procedure time if compared with pharmacological thrombolysis. The clinical indications for percutaneous intervention in PE are discussed in the text.

Endovascular management of venous thrombotic diseases of the upper torso and extremities

Central venous thrombosis in the upper torso can be either primary, occurring as a result of longstanding extrinsic compression, or secondary, resulting from an acquired intrinsic occlusive disease or foreign body. As in lower extremity deep vein thrombosis (DVT), anticoagulation therapy is the mainstay of therapy in upper torso and upper extremity DVT. However, in the presence of severely symptomatic acute thrombosis, pharmacologic and/or mechanical thrombolytic therapy represent the main invasive form of therapy for these conditions. After clearance of the acute thrombotic component, definitive management in patients with underlying anatomic abnormalities can be undertaken. Primary subclavian axillary vein thrombosis caused by extrinsic obstruction at the thoracic outlet is treated with thrombolytic therapy and anticoagulation followed by surgical decompression, whereas secondary causes of central venous obstruction and thrombosis are usually amenable to endovascular treatment with balloon angioplasty and stent placement. Postoperative interval anticoagulation is usually recommended. In addition to clinical follow-up, imaging follow-up with duplex sonography or conventional venography is usually recommended to assess the presence of restenosis and/or residual compression.

Low-power transverse ultrasonic treatment of portal vein thrombosis in an animal model

PURPOSE

The authors have recently developed a small-diameter, thin, flexible ultrasonic catheter device that permits the removal of thrombus by low-power transverse ultrasonic cavitation energy. In this study, the authors sought to determine whether this device could be used to eliminate portal vein thrombosis in an animal model.

MATERIALS AND METHODS

In five anesthetized pigs, a total of six occlusions of the left portal vein were achieved with use of autologous clot with (n = 2) or without (n = 4) thrombin injection (250 U) introduced via a 7-F transhepatic catheter/sheath system. Angiographic examination documented complete occlusion of this vessel. The 75-cm-long, 21-gauge ultrasonic catheter (Resolution) was introduced into the clot under angiographic guidance via the transhepatic sheath. Transverse-wave ultrasonic energy was then delivered from the distal 5 cm of the probe at 3.5 W +/- 10% power for up to 6 minutes. Repeat angiographic studies were performed to document patency. After the procedure, gross and histopathologic examinations were performed.

RESULTS

Restoration of patency of the main left portal vein was documented in all cases at angiography, with no evidence of residual clot fragments in the major branches. However, side branches demonstrated small thrombotic plugs on pathologic examination. No complications such as perforation of the vessel adjacent to the active ultrasonic tip were encountered. Virtually all thrombolysis was documented to occur within the first minute of energy application. At gross pathologic examination, there was no evidence of damage to the portal vein, and histopathologic examination demonstrated minimal intimal disruption without damage to the media.

CONCLUSIONS

This preliminary animal study suggests the feasibility of a percutaneous transhepatic approach to the treatment of portal vein thrombosis with use of low-power ultrasonic cavitation energy. With further study, this method may have potential for the treatment of thrombotic disease, thereby offering novel therapy to patients with thrombotic vascular occlusions.

Prototype percutaneous thrombolytic device: preclinical testing in subacute inferior vena caval thrombosis in a pig model

PURPOSE

To develop an animal model of subacute inferior vena caval (IVC) thrombosis and apply this model in evaluating the safety and efficacy of a prototype percutaneous thrombolytic device for restoring patency.

MATERIALS AND METHODS

In 11 pigs, a stent with a ligature in the middle was placed in the IVC. Thrombin was injected to induce thrombosis. Hemostasis was achieved by using an occlusion balloon. The stent was ligated to prevent thrombus migration. Five to 8 days after thrombus induction, the ligature was broken and the stent fully deployed. In 10 animals, thrombectomy was performed by using the percutaneous thrombolytic device. A vena caval filter was inserted at the beginning of each declotting procedure. Thrombus removal percentage was estimated and pulmonary angiograms obtained to detect embolism before and after thrombectomy. The IVC was analyzed histologically. To determine thrombus composition, one animal was sacrificed without thrombectomy. Concerning procedural safety, failure of the stent delivery system, stent migration, and venous perforation due to balloon inflation and the stent placement or thrombectomy procedure were evaluated.

RESULTS

Thrombus creation was successful in all animals. Fragmentation led to 75%--100% thrombus removal with flow restoration in all cases. There were no episodes of stent delivery failure, stent migration, or venous perforation. No significant pulmonary embolism was observed. In one case, a vessel dissection was identified at histologic examination.

CONCLUSION

In this animal model of IVC thrombosis, the percutaneous thrombolytic device is effective and safe for clot removal.

The use of mechanical thrombectomy devices in the management of acute peripheral arterial occlusive disease

A number of percutaneous mechanical thrombectomy devices are currently being used or undergoing clinical evaluation for the treatment of acute and chronic limb-threatening ischemia. Preliminary studies on the safety, efficacy, and device limitations have spurred an interest in percutaneous techniques for thrombus debulking as stand-alone therapy or an adjunct to pharmacologic thrombolysis. The devices have various mechanisms or combinations of mechanisms to optimize thrombus removal. Efficacy of thrombus removal is balanced by the propensity for vessel wall damage and distal embolization, especially for wall-contact devices (Arrow-Trerotola device and Cragg and Castañeda brushes). Initial experience in hemodialysis graft occlusion has subsequently moved on to peripheral arterial occlusions. Although the U.S. Food and Drug Administration has approved eight mechanical thrombectomy devices (MTDs) for use in thrombosed hemodialysis grafts, only the AngioJet LF140 is currently approved for use in peripheral arterial occlusive disease. Nevertheless, numerous clinical articles and abstracts have reported the "off-label" use of MTDs in the management of limb-threatening ischemia. A description of the eight MTDs and a review of the current literature on use of MTDs for acute peripheral arterial occlusive disease are provided.

Rheolytic thrombectomy in the management of acute and subacute limb-threatening ischemia

PURPOSE

To evaluate the use of a percutaneous mechanical thrombectomy (PMT) catheter (AngioJet) as an initial treatment for acute (<2 weeks) and subacute (2 weeks to 4 months) arterial occlusion of the limbs.

MATERIALS AND METHODS

A total of 86 (acute, n = 65; subacute, n = 21) patients were available for retrospective analysis, averaging 65 +/- 14 years of age. Outcomes assessed include initial angiographic success (failure = less than 50% luminal restoration [LR]; partial success = 50%-95% LR; success = more than 95% LR), pre- and postprocedural ankle-brachial index (ABI), device-related and systemic complications, 1-month amputation, mortality, and short-term patency.

RESULTS

Angiographic success was evaluated in 83 of 86 patients (guide wire unable to traverse lesion in three patients). The procedure failed in 13 of 83 (15.6%) patients, partial success was seen in 19 of 83 patients (22.9%), and successful recanalization was noted in 51 of 83 patients (61.4%). Adjunctive thrombolysis was used in 50 of 86 patients (58%). However, thrombolysis resulted in angiographic improvement at the site of PMT in only seven of 50 of these patients (14%). Adjunctive thrombolysis was uniformly unsuccessful in patients in whom initial PMT failed. The median increase in ABI was 0.64 (95% CI: 0.43-0.81). Success was more likely in the setting of in situ thrombosis, with 61 of 68 (90%) procedures successful, compared to embolic occlusions, with nine of 15 (60%) procedures successful (P =.011). Angiographic outcome was not dependent on the duration of occlusion (acute, 51 of 62; subacute, 19 of 21; P =.35) or the conduit type (graft, 28 of 31; native vessel, 42 of 52; P =.35). An underlying stenosis was identified in 53 of the 70 patients (75.7%) with a successful PMT, and 51 of these 53 unmasked lesions were successfully treated. Follow-up data were available in 56 patients for patency assessment at a median of 3.9 months (range, 0.1-28.5 months). Patency at 6 months was 79% (95% CI: 65-92). Systemic complications occurred in 16.3% of patients, local complications were noted in 18.6%, and 1-month amputation and mortality rates were 11.6% and 9.3%, respectively.

CONCLUSION

PMT offers the potential to rapidly reestablish flow to an ischemic extremity and may be the only available treatment option in patients at high risk for open surgery or with contraindications to pharmacologic thrombolysis.

Creation of radiopaque thrombi for in vivo experiments

PURPOSE

A number of percutaneous thrombectomy devices are undergoing investigation for treatment of patients with venous thromboembolism. Use of radiopaque thrombus to monitor thrombus delivery and assess thrombectomy has been previously reported. The purpose of this project was to quantitatively test the effect of mixing different ratios of blood and contrast material to facilitate maximum thrombus formation and radiopacity.

MATERIALS AND METHODS

The following ratios of blood and contrast material were mixed: 2 mL blood to 8 mL contrast material (ratio = 0.25), 4 mL blood to 6 mL contrast material (ratio = 0.67), 6 mL blood to 4 mL contrast material (ratio = 1.5), and 8 mL blood to 2 mL contrast material (ratio = 4). Contrast material was added at day 0, 3, or 6. Each sample received one of two ionic contrast agents to opacify the clots. At day 14, thrombus mass and opacity were determined.

RESULTS

Three combinations of blood and contrast material produced maximum thrombus and radiopacity. These were sodium iothalamate 30% with a ratio of 4 with contrast material added on day 0 and sodium iothalamate 60% with a ratio of 1.5 with contrast material added on day 3 or 6.

CONCLUSIONS

When forming radiopaque thrombi, significant differences can result from the ratio of blood to contrast material used. Contrast material type can also affect radiopacity and mass formed. The use of optimal ratios of blood to contrast material should maximize device evaluation with minimal wasting of valuable resources such as test subjects, physician time, and equipment.

Percutaneous venous thrombectomy with the use of a balloon sheath: first in vitro investigations of a new low-tech concept

RATIONALE AND OBJECTIVES

To test mechanical thrombectomy of extensive iliofemoral and iliocaval thrombi in an in vitro flow model with the use of 12F and 18F balloon sheaths.

METHODS

Newly developed 12F and 18F sheaths were evaluated in four vessel models (simulation of femoral, iliofemoral, iliocaval, and caval thrombi by clotted bovine blood in a flow model). After retrograde insertion of the sheath and blocking of the vessel proximal to the thrombus by inflating the balloon, mechanical fragmentation was performed coaxially through the sheath lumen by using a 7F pigtail rotation device. With an occlusion balloon catheter, residual thrombi were withdrawn to the orifice of the sheath and aspirated. Twelve silicone tubes occluded by thrombi were recanalized in each setting. In the latex model, seven recanalizations were performed.

RESULTS

All clots were removed completely within a treatment duration of 2 to 14 minutes. Fluid loss during the procedure was 29.6 to 129.3 mL for the femoral flow model, 61.9 to 137.2 mL for the iliofemoral model, 74.5 to 163.4 mL for the iliocaval model, and 102.7 to 236.7 mL for the caval model. No fragments were washed downstream. In four settings, small residual thrombi were attached to the balloon after deflation of the sheath.

CONCLUSIONS

Clot amounts up to 171 g were removed quickly and completely by using these large-caliber balloon sheaths. Fluid loss from aspiration was negligible. Balloon occlusion prevented embolization of thrombus fragments proximal to the sheath. Further studies are needed to prove the efficacy of this technique in vivo.

A new rotational thrombectomy catheter: system design and first clinical experiences

PURPOSE

To describe a new catheter for the percutaneous mechanical removal of fresh and organized thrombi, and to assess its efficacy and safety in vitro and in vivo.

METHODS

The catheter consists of a coated stainless steel spiral that rotates at 40,000 rpm over a guidewire inside the whole length of an 8 Fr, single-lumen, polyurethane catheter, driving a dual-blade cutting crown. Abraded occlusion material is sucked into the catheter head through distal side holes and transported by the spiral into a reservoir at the proximal end. The efficacy of the device was tested in arterial models and fresh bovine carotid arteries (n = 72). In a clinical pilot study 10 patients (8 women, 2 men; mean age 70.6 +/- 10.1 years) with occlusions of the superficial femoral artery (2-12 cm, mean 5.8 cm), not older than 4 weeks, underwent thrombectomy with the new catheter.

RESULTS

In arterial models and bovine cadaver arteries the catheter completely removed fresh thrombi. Occlusion material of higher consistency was cut into particles of 100-500 micron and transported outside. Thrombectomy was successful and vessel patency restored in all 10 patients. The ankle/brachial pressure index significantly (p < 0.0005) increased from 0.41 +/- 0. 18 before intervention to 0.88 +/- 0.15 after 48 hr and to 0.84 +/- 0.20 after 3 months. Two reocclusions occurred within 14 days after the intervention.

CONCLUSION

Thrombectomy with the new device appears to be feasible and safe in patients with acute and subacute occlusions of the femoropopliteal artery.

Comparison of the angiojet rheolytic catheter to surgical thrombectomy for the treatment of thrombosed hemodialysis grafts. Peripheral AngioJet Clinical Trial

PURPOSE

To compare the clinical effectiveness of the AngioJet F105 rheolytic catheter to that of surgical thrombectomy for the treatment of thrombosed hemodialysis grafts.

MATERIALS AND METHODS

This was a multicenter, prospective, randomized trial comparing technical success, primary patency, and complication rates. A total of 153 patients were enrolled: 82 patients in the AngioJet group and 71 patients in the surgical thrombectomy group. Patient follow-up was performed 24-48 hours, 1 month, and 6 months after the procedures.

RESULTS

Technical success, as defined by the patient's ability to undergo hemodialysis treatment, was 73.2% for the AngioJet group and 78.8% for the surgical thrombectomy group (P = .41). The primary patency rates of the AngioJet group were 32%, 21%, and 15% at 1, 2, and 3 months, respectively. The primary patency rates for the surgical group were 41%, 32%, and 26% at 1, 2, and 3 months, respectively. This difference approached statistical significance (P = .053). The groups had similar complication rates-14.6% in the AngioJet group and 14.1% in the surgery group-although the surgery group had more major complications (11.3%). In the AngioJet group, there was a transient increase in plasma-free hemoglobin, which normalized within 24-48 hours.

CONCLUSIONS

The AngioJet F105 catheter provides similar clinical results when compared to surgical thrombectomy for the treatment of thrombosed hemodialysis grafts. The difference in patency rates between these two techniques approached statistical significance. In addition, results of both thrombectomy methods were inferior to those suggested by the Dialysis Outcomes Quality Initiative guidelines.

Mechanical thrombectomy in hemodialysis access shunts using a 5F pigtail rotation catheter. In vitro and in vivo investigations

RATIONALE AND OBJECTIVES

To evaluate the feasibility of mechanical thrombectomy in occluded hemodialysis access shunts by using a newly developed 5F pigtail rotation catheter.

METHODS

Thrombosed hemodialysis access shunts were simulated by clotted bovine blood in silicone tubing (diameter 6 mm). After retrograde and antegrade sheath placement (6F), mechanical fragmentation was performed using a 5F rotatable pigtail device. Average tube length was 27 to 47 cm; average thrombus weight was 5 to 11.9 g (8.2 +/- 1.59). Clinical application involved six patients with fresh shunt occlusions (three Brescia-Cimino shunts, three Gore-Tex shunts).

RESULTS

Using the in vitro setup, the device was able to restore a continuous lumen within 10 minutes with no remaining wall-adherent thrombi. The average amount of particles in the effluent was 3.0 g (2.0 to 3.9) for particles < or = 1.0 mm and 0.67 g (0.44 to 0.96) for particles > or = 0.2 mm wet weight; (compared with initial thrombus weight, 30.7% and 1.1%, respectively). Clinically, all six hemodialysis access shunts were successfully recanalized. Technical problems did not occur. There were no clinical symptoms indicating pulmonary embolism in any of the treated patients.

CONCLUSIONS

In our experimental setup as well as under clinical conditions, effective treatment of occluded hemodialysis access sites was achieved. The pigtail rotation device is an easy-to-handle, inexpensive alternative to mechanical thrombus fragmentation in occluded hemodialysis access shunts. The rate of emboli in the effluent vein of approximately one third of the initial thrombus weight must be taken into consideration in frequent intraindividual use of this technique.

Evaluation of a modified arrow-trerotola percutaneous thrombolytic device for treatment of acute pulmonary embolus in a canine model

PURPOSE

Massive pulmonary embolus (PE) is often rapidly fatal. Surgical thrombectomy has a mortality rate as high as 74%. Multiple percutaneous methods have been tested with limited success. The purpose of this study was to evaluate the Arrow-Trerotola percutaneous thrombolytic device (PTD) for (i) the ability to clear pulmonary embolus and (ii) the effect on normal pulmonary vasculature. These were tested in a canine model.

MATERIALS AND METHODS

Iatrogenic unilateral massive PEs were created in nine canines. These PEs were then treated with the PTD. The device was also activated in the normal pulmonary artery. Immediately after treatment, six animals were killed. Three animals were allowed to recover and underwent pulmonary arteriography 1 month later to evaluate pulmonary hypertension, stenosis, or occlusion; they were then killed. Autopsy specimens were evaluated for histologic evidence of acute or chronic vascular injury.

RESULTS

Acutely, the PTD effectively thrombolysed the PE in all animals. Histologically, there was moderate intimal injury, but no evidence of pulmonary artery disruption. There was one device failure. One month after treatment, there was no radiographic evidence of pulmonary stenosis at device activation sites, no pulmonary hypertension, and only mild histologic evidence of scar formation.

CONCLUSION

In preliminary animal testing, the PTD is safe and effective for treating large central pulmonary emboli. Human clinical trials are warranted.