Percutaneous pulmonary thrombectomy

Hybrid treatment with angiographic catheter in massive pulmonary embolism: mechanical fragmentation and fibrinolysis

PURPOSE

Massive pulmonary embolism is a severe clinical condition that requires prompt therapeutic intervention. We report our experience with a hybrid treatment involving systematic fragmentation of the embolus with an angiographic catheter associated with fibrinolytic therapy over the following days.

MATERIALS AND METHODS

From 1999-2005 we treated 164 patients with massive pulmonary embolism. We used the same angiographic catheter for mechanical fragmentation and for administration of the fibrinolytic agent (24-72 h). Results were assessed on the basis of changes in mean pulmonary artery pressure.

RESULTS

After fragmentation with the angiographic catheter, we observed four types of haemodynamic behaviour: in 61 patients (41.4%), mean pulmonary artery pressure fell rapidly below 30 mmHg; in 38 patients (23.1%), two passes were required to achieve the same result; in 32 patients (19.5%) three passes were required. In the remaining 26 patients (15.8%), at no time did the mean pulmonary artery pressure fall below 35 mmHg. The only two deaths occurred in this last group.

CONCLUSIONS

Mechanical fragmentation with the angiographic catheter and administration of fibrinolytic agents effectively brought about a rapid improvement in patients' clinical status by moving the embolus towards the periphery.

Evaluation of a Newly Developed Percutaneous Thrombectomy Basket Device in Sheep With Central Pulmonary Embolisms

OBJECTIVE

The authors studied the development of a thrombectomy device that is adequately steerable and quickly placeable in case of extensive pulmonary embolism.

MATERIALS AND METHODS

The device consists of a self-expandable nitinol basket mounted at a catheter-tip, which allows suction and extraction of thrombus material. Five in vitro tests were performed followed by tests in 6 sheep. In vivo thrombus material was introduced through a jugular vein to produce pulmonary embolism. After catheter insertion over the right femoral vein, the basket was placed adjacent to the pulmonary embolus and the extraction procedure was performed.

RESULTS

In in vitro tests, the extracted thrombus amount varied between 60% and 95%. In animal experiments, the extracted amount varied between 30% and 95% as determined angiographically. Limiting factors were steerability and optimal positioning of the basket in relation to the embolus.

CONCLUSIONS

Extraction of pulmonary embolism with the self-expanding suction basket is feasible. However, successful recanalization is limited by catheter maneuverability in the pulmonary arterial system.

Inhaled nitric oxide as an adjunct to suction thrombectomy for pulmonary embolism

Pulmonary suction thrombectomy can be a successful interventional tool in the treatment of pulmonary thromboembolism. Removal of clot burden typically results in prompt recovery of hemodynamic stability and improved oxygenation. However, in rare cases, clot removal does not sufficiently improve the clinical situation. Herein, two patients with massive pulmonary thromboembolism are presented whose condition improved only after they received nitric oxide as an adjunct to pulmonary suction thrombectomy. The treatment with this inhalable vasodilator was based on the hypothesis that prolonged ischemia had induced microcirculatory vasospasm, persistent after removal of the central clot.

Recent Advances in Interventional Radiology for Acute Massive Pulmonary Thromboembolism

Acute massive pulmonary thromboembolism is life-threatening and requires vigorous treatment. Anticoagulation is the most traditional treatment for pulmonary thromboembolism, but may not be sufficient for massive thromboemboli. Systemic thrombolytic therapy and surgical thrombectomy are the traditional therapeutic options in this situation. Catheter-directed thrombolysis, percutaneous embolectomy and, more recently, percutaneous thrombus fragmentation techniques using specialized devices are now available to treat the most severe cases of massive pulmonary thromboembolism. The success of these techniques depends on a thorough understanding of the mechanism of action of each of the devices and familiarity with the relevant catheterization techniques. We present a review of currently available equipment and techniques, and describe our work with hybrid treatment using a combination of mechanical fragmentation, localized fibrinolysis and clot aspiration.

Hybrid treatment of acute massive pulmonary thromboembolism: mechanical fragmentation with a modified rotating pigtail catheter, local fibrinolytic therapy, and clot aspiration followed by systemic fibrinolytic therapy

OBJECTIVE

We sought to evaluate the efficacy and safety of a hybrid treatment for acute massive pulmonary thromboembolism in patients with hemodynamic impairment by combining mechanical fragmentation, local thrombolysis, and clot aspiration.

SUBJECTS AND METHODS

Within a period of 35 months, 25 patients with hemodynamic impairment (eight men and 17 women; age range, 35-77 years) were treated with mechanical thrombus fragmentation using a modified rotating pigtail catheter. After embolus fragmentation, all patients received an intrapulmonary injection of recombinant human-tissue plasminogen activator and then underwent manual clot aspiration with a large-lumen percutaneous transluminal coronary angioplasty guide catheter.

RESULTS

All the patients survived, and their clinical status improved. Posttreatment angiography showed an improvement in pulmonary perfusion in all patients (mean Miller score before treatment, 22.2; after treatment, 13.6; p < 0.01). Mean pulmonary artery pressure decreased from 32.6 to 23.4 mm Hg (p < 0.01). Mean treatment time was 124.6 min.

CONCLUSION

Hybrid treatment with mechanical fragmentation using a rotating pigtail catheter combined with local fibrinolysis and manual clot aspiration resulted in a rapid and safe improvement in the hemodynamic condition of patients with acute massive pulmonary thromboembolism. This hybrid treatment appears to be especially useful in patients at high risk for right ventricular failure and is a minimally invasive alternative to surgical embolectomy.

Tumor Thromboembolism Masquerading as Bland Pulmonary Embolism

Catheter-based interventions provide an important alternative to medical surgical management of massive central pulmonary thromboembolism. Because this option is increasingly being used, it is important to recognize that not all pulmonary thromboemboli are bland. The authors describe two cases in which tumor masqueraded as bland thromboembolism. Identification of tumor thromboembolism may help to alter future work-ups, provide useful prognostic information for a patient, and affect future treatment options.

Adjunctive techniques in percutaneous mechanical thrombectomy

Percutaneous mechanical thrombectomy is an established method in interventional radiology and refers to the removal of acute embolic or thrombotic occlusive material in arteries, veins, or vascular grafts using percutaneous transluminal methods. However, initial complete removal of occlusive material can be achieved only in a minority of patients. The amount of removed material varies with the age and composition of the occlusive material. To achieve sufficient revascularization, adjunctive use of a variety of percutaneous endovascular recanalization techniques is necessitated. Additional treatment with local intra-arterial fibrinolysis, balloon angioplasty, stent implantation, endoluminal atherectomy, and other measures results in primary technical success rates of 70% to 100% for revascularization of acutely occluded vessels. The above-mentioned different techniques should not be viewed as competitive treatment modalities, rather a synergistic approach should be offered. The aim of this report is to review different adjunctive techniques in percutaneous mechanical thrombectomy with emphasis on techniques, mechanisms of action, experimental and clinical results, potential complications, and their potential role in view of clinical pathways to treat acute limb ischemia.

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.

Revascularization of a thrombosed aortopulmonary shunt with the use of the AngioJet thrombectomy system

We report the use of the AngioJet F140 rheolytic catheter to recannalize an acutely thrombosed aortopulmonary shunt in a 21-year-old female with palliated, complex congenital heart disease. After extracting the thrombus that filled the entire length of the shunt, three stents were placed at sites where the lumen was compromised by distortion or thrombus. Unobstructed flow was restored to the left pulmonary artery that persisted at 1-year follow-up.

Evaluation of a spiral nitinol temporary inferior vena caval filter

RATIONALE AND OBJECTIVES

The authors performed this study to evaluate the (a) ability of a prototype temporary inferior vena caval (IVC) filter to trap and retain emboli in an ex vivo flow circuit, (b) feasibility of filter placement and removal via a superficial vein in sheep, and (c) intermediate-term effects of the filter on the insertion vein and at the filter site.

MATERIALS AND METHODS

In an iliocaval circuit, embolus capture with the prototype filter was compared to that with a Greenfield filter. In addition, prototype filters were placed into the infrarenal IVC in six sheep. Placement via a superficial venous route was initially attempted. Inferior vena cavography was performed weekly, and filters were removed after 2, 3, or 4 weeks (n = 2 each). Two weeks after the filters were removed, vena cavograms were obtained, the animals were sacrificed, and the IVC was evaluated at pathologic examination.

RESULTS

The prototype filter captured all emboli, and the Greenfield filter captured 70%-100% of emboli. Successful placement via a superficial venous route was accomplished in only two sheep owing to small vein caliber; four filters were placed via a deep vein. Adverse events included perifilter thrombus, insertion site infection, and caudal migration. Two sheep died before filter removal owing to sepsis and anesthetic complications. The filters in the remaining four sheep were easily and successfully removed. Five sheep had stenosis at the filter site, and fibrosis with acute and chronic inflammation was seen at microscopic examination.

CONCLUSION

The prototype filter trapped emboli as well as the Greenfield filter. Insertion via a superficial route, however, is possible only if the access vein is of an adequate size.

Interventional therapy for pulmonary embolism

Venous thromboembolism is a common cause of death. Acute massive pulmonary embolism (PE) is life-threatening and may require vigorous more invasive treatment. Several risk factors are related to increased incidence of massive PE. Anticoagulation is the most traditional treatment for PE but may not suffice in cases of massive PE. Systemic thrombolytic therapy, catheter-directed thrombolysis, percutaneous embolectomy, and more recently, percutaneous thrombus fragmentation techniques with a multitude of devices are now available to treat the most severe cases of massive PE. Successful treatment of PE includes implementation of a treatment protocol and the use of associated techniques and devices.

Massive pulmonary embolism: treatment with the hydrolyser thrombectomy catheter

PURPOSE

To assess the efficacy of clot removal with use of the Hydrolyser thrombectomy catheter in acute massive pulmonary embolism (PE).

MATERIALS AND METHODS

Eleven patients (eight women, three men) with a mean age of 61 (range, 37-79) years with acute massive PE underwent percutaneous mechanical thrombectomy (PMT) with use of the Hydrolyser. In four patients with no contraindication, fibrinolysis was performed with use of urokinase at low doses after thrombectomy.

RESULTS

Ten patients (90.91%) recovered from massive PE and were discharged within 11 days. The Urokinase Pulmonary Embolism Trial angiographic severity indexes (mean +/- SD) were 14.7 +/- 2.6 and 7.5 +/- 2.7, respectively, before and after thrombectomy (P < .001). Partial arterial pressures of O2 increased from 72.8 mm Hg +/- 16.4 to 93.5 mm Hg +/- 5.6 (P < .005). Pulmonary artery pressure decreased from 45.5 mm Hg +/- 14.2 to 29.5 mm Hg +/- 13.6 after thrombectomy (P < .0001). Calculated by semiquantitative computed analysis, PMT with use of the Hydrolyser removed 74.06% of thrombus +/- 13.46%. One patient developed self-limited hemoptysis immediately after thrombectomy. One patient died during the procedure secondary to PE.

CONCLUSION

PMT with use of the Hydrolyser is effective and safe in massive PE, resulting in improved hemodynamics and blood oxygenation and decreased pulmonary artery pressure. It offers an alternative to fibrinolysis and surgical thrombectomy.

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.

A new thrombectomy catheter device (AngioJet) for the disruption of thrombi: An in vitro study

In this study we examined a new thrombectomy catheter device. Different kinds of in vitro generated thrombi and cadaver thrombi were disrupted in test tubes. The mean disruption rate (and disruption time for 1 g of thrombus) was 225 +/- 65 mg/sec (5 +/- 2 sec) for whole-blood, 117 +/- 60 mg/sec (12 +/- 9 sec) for fibrin, 41 +/- 18 mg/sec (30 +/- 18 sec) for mixed, 70 +/- 42 mg/sec (17 +/- 5 sec) for unorganized, 45 +/- 8 mg/sec (22 +/- 4 sec) for partly, and 5 +/- 1 mg/sec (216 +/- 29 sec) for completely organized cadaver thrombi (P < 0.05). More than 99% of fragmented particles of whole-blood thrombi were 0-12 microm in diameter. The particle size of fibrin, mixed, and cadaver thrombi was similar, with 25%-40% of particles between 0-12 microm, 55%-71% >12-24 microm, and 2%-7% >24 microm. The device may be effectively used in the therapy of massive pulmonary embolism or acute peripheral and coronary artery syndromes when medical thrombolysis is contraindicated and organization of thrombus is absent. Further studies need to be performed to investigate the potential effects of particle microembolization. Cathet. Cardiovasc. Intervent. 47:381-389, 1999.

Venous thromboembolism in the intensive care unit

Venous thromboembolic disease has emerged as a significant cause of morbidity and mortality in hospitalized patients. This article reviews the salient features of venous thromboembolism as they pertain to the critically ill. Emphasis is placed on identifying risk factors, diagnostic strategies, prophylaxis, and treatment of this disorder. Deep venous thrombosis and pulmonary embolism, both being manifestations of the same disease processes, are considered together in this discussion of venous thromboembolism.

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.

Fragmentation of massive pulmonary embolism using a pigtail rotation catheter

STUDY OBJECTIVES

The purpose of this study was the evaluation of the efficacy and safety of mechanical fragmentation of acute massive pulmonary emboli with a rotatable pigtail catheter.

MATERIAL AND METHODS

Ten patients (4 female, 6 male, age 53.8+/-9.5 years) with acute massive pulmonary embolism with hemodynamic impairment were included in the study. The fragmentation catheter device (William Cook Europe A/S; Bjaerverskov, Denmark) consisted of a 5F catheter embedded in a flexible 5.5F sheath. Pulmonary emboli were fragmented by mechanical action of the recoiled rotating pigtail, while the guide wire was exiting an oval side hole proximal to the pigtail tip. In eight cases, an additional thrombolysis was performed.

RESULTS

Fragmentation was successful in 7 of 10 patients. Average percentage of recanalization by fragmentation was 29.2+/-14.0%, and 36.0+/-10.0% exclusively of the seven successful cases. Average shock index decreased significantly prefragmentation to postfragmentation from 1.52 to 1.22 (p = 0.03) and to 0.81 48 h later (p < 0.001). Decrease of the average mean arterial pulmonary pressure prefragmentation to postfragmentation was insignificant (from 33 to 31 mm Hg, p = 0.14); further decrease within the 48 h follow-up was highly significant (from 31 to 21 mm Hg, p < 0.001) due to a synergy of fragmentation and thrombolysis (average dose 63+/-25 mg plasminogen activator). There were no procedure-related complications. Overall mortality rate was 20%.

CONCLUSION

Fragmentation of massive pulmonary emboli with the pigtail rotation catheter achieved rapid partial recanalization in most cases, with ease of instrumentation, and without complications. Hemodynamic stabilization was completed in synergy with thrombolysis.