Fragmentation of massive pulmonary embolism using a pigtail rotation catheter

Unmet Needs and Future Direction for Pulmonary Embolism Interventions

Venous thromboembolism (VTE) usually develops in the deep veins of the extremities. Pulmonary embolism (PE) is a type of VTE that is most commonly (∼90%) caused by a thrombus that originates from the deep veins of the lower extremities. PE is the third most common cause of death after myocardial infarction and stroke. In this review, the authors investigate and discuss the risk stratification and definitions of the aforementioned categories of PE and further explore the management of acute PE along with the types of catheter-based treatment options and their efficacy.

Rivaroxaban plus aspirin versus acenocoumarol to manage recurrent venous thromboembolic events despite systemic anticoagulation with rivaroxaban

INTRODUCTION

The evaluation and management of patients who sustain recurrent thromboembolic events while taking therapeutic anticoagulation have not been well characterized; moreover, there has been no systematic review or randomized trial focused on treating patients with recurrent deep vein thrombosis (DVT) and pulmonary embolism (PE) during anticoagulant treatment. Therefore, we developed a pilot trial to compare rivaroxaban plus aspirin versus acenocoumarol in patients with recurrent venous thromboembolism despite ongoing anticoagulation with rivaroxaban.

MATERIALS AND METHODS

The study was a multicenter, randomized clinical trial. We randomly assigned patients with objectively documented recurrent venous thromboembolism to receive rivaroxaban (20 mg once a day) plus aspirin (300 mg once a day) or an adjusted dose of acenocoumarol. The study was designed to evaluate the incidence of recurrent thromboembolic events (recurrent ipsilateral or contralateral DVT, PE, ischemic stroke, and myocardial infarction) and hemorrhagic events.

RESULTS

A total of 58 patients were randomized: 28 were allocated to the rivaroxaban plus aspirin group and 30 to the acenocoumarol group. After 90 days of follow-up, three recurrent thromboembolic events (primary outcome) occurred in the acenocoumarol group - two DVTs and one ischemic stroke - and zero events in the rivaroxaban plus aspirin group (risk ratio [RR] 0.15; 95 % confidence interval [CI] 0.008-2.83; P = 0.20). Minor bleeding occurred in five patients in the acenocoumarol group and zero in the rivaroxaban plus aspirin group (RR 0.09; 95 % CI 0.005-1.68; p = 0.10). There was one non-fatal gastrointestinal major bleed in the rivaroxaban plus aspirin group.

CONCLUSIONS

In this pilot study, there were no significant differences in any outcome assessed; however, recurrent thromboembolic events and minor bleeding events occurred numerically less frequently in the rivaroxaban plus aspirin group. These data suggest the need to carry out more extensive randomized studies with sufficient statistical power to clarify these results.

Efficacy and safety of hydro-mechanical defragmentation in intermediate- and high-risk pulmonary embolism

BACKGROUND

Pulmonary embolism (PE) is the third most common acute cardiovascular syndrome. Percutaneous catheter directed hydro-mechanical defragmentation (HMD) is one of the recommended treatment options for PE in patients with contraindications to thrombolytic therapy or failed systemic thrombolysis (ST). We aimed to identify the safety and outcomes of catheter directed HMD in patients with high-risk PE. This nonrandomized controlled trial enrolled all patients with confirmed diagnoses of high- and intermediate-high-risk PE from October 2019 till January 2021. Fifty patients were included and divided into two groups by the PE response team according to the presence or absence of a contraindication for ST. Group B (ST) consists of 25 patients and group A (HMD) of 25 patients who cannot receive ST.

RESULTS

The two groups were comparable regarding baseline clinical characteristics with mean age 51 ± 13 years. In group A, systolic blood pressure (BP) and oxygen saturation increased after 24 h (p = 0.002) and 48 h (p < 0.001) compared to pre-HMD procedure. Mean pulmonary artery systolic pressure (PASP) and respiratory rate (RR) decreased after 48 h and at 30 days (p < 0.001) compared to pre-HMD procedure. The increase in systolic BP and oxygen saturation were significantly higher in HMD group compared with ST group after 48 h and at 30 days (p < 0.007). The decrease in PASP and RR was significantly higher in HMD group compared to ST group after 48 h and at 30 days (p < 0.001). Mortality rate at 30 days was 20% in HMD group compared to 32% in ST group.

CONCLUSIONS

Catheter directed HMD for high-risk and intermediate-high-risk PE is safe and effective with acceptable mortality Trial registration Clinical trial ID: NCT04099186.

Outcomes of catheter-directed interventions in high-risk pulmonary embolism-a retrospective analysis

BACKGROUND

First-line treatment of high-risk pulmonary embolism with persistent hypotension and/or signs of shock is intravenous thrombolysis. However, if thrombolysis is contraindicated due to risk of serious bleeding, or if it yields insufficient effect, surgical thrombectomy or catheter-directed intervention (CDI) plus anticoagulation is recommended. The aim of this study was to assess the outcomes of the CDI modality introduced in a tertiary referral centre in 2013.

METHODS

Retrospective comparison between patients treated with CDI plus anticoagulation (n = 22) and patients treated with anticoagulation only (n = 23) as used before the CDI technique was available. The main outcomes of interest were 90-day survival and reduction of right to left ventricle diameter (RV/LV) ratio, using the Fischer's exact test and a mixed model, respectively, for statistical analysis.

RESULTS

Ninety-day survival was 59% after CDI and 61% after anticoagulation only; P = .903. The rate of RV/LV ratio reduction was 0.4 units higher per 24 hours in the CDI group (median 2.1 pre-treatment), than in the anticoagulation only group (median 1.3 pre-treatment); P = .007.

CONCLUSION

In patients with high-risk pulmonary embolism, 90-day survival was similar after treatment with CDI plus anticoagulation compared to anticoagulation only. The mean reduction in RV/LV ratio was larger in the CDI group. Our results support the use of CDI in selected patients, respecting the limitations and potential side effects of each technical device used.

Review of pulmonary emboli and techniques for their mechanical removal to inform device design

Pulmonary emboli present a significant burden of disease, with limited treatment options for some patients. Mechanical devices for pulmonary emboli removal are becoming increasingly prevalent though more work remains to be done. This paper briefly discusses the mechanical properties of pulmonary emboli, the disease state they cause, and the existing embolectomy devices. The goal of this paper is to aid the design of minimally invasive mechanical pulmonary emboli removal devices, by providing a review of this topic as well as some key design specifications.

Interventional Radiology Therapy: Inferior Vena Cava Filter and Catheter-based Therapies

Endovascular management of pulmonary embolism can be divided into therapeutic and prophylactic treatments. Prophylactic treatment includes inferior vena cava filter placement, whereas endovascular therapeutic interventions include an array of catheter-directed therapies. The indications for both modalities have evolved over the last decade as new evidence has become available.

[New aspects of thrombolysis and thrombectomy in pulmonary embolism]

Pulmonary embolism is a potentially life-threatening disease, which can present with varying severity. Based on an emergency risk stratification, the initial treatment strategy should be chosen without delay. While patients with a low mortality risk can be treated in an outpatient setting, patients at high risk should proceed to immediate recanalization by thrombolysis or thrombectomy. Systemic thrombolysis is the first line therapy in the absence of contraindications. The dosing (low versus full dose) and application (systemic versus local via a catheter) of alteplase, the most frequently used agent, is the subject of a number of current studies with the goal to reduce the risk of bleeding. In the case of contraindications for systemic thrombolysis surgical or alternatively, interventional thrombectomy should be performed. This article discusses these procedures in the light of the currently available literature.

Catheter-based therapies in acute pulmonary embolism

AIMS

To provide a systematic review of catheter-based therapies of acute pulmonary embolism.

METHODS AND RESULTS

Studies published in peer-reviewed journals before February 2017 were included and categorized according to the mechanism of thrombus removal: fragmentation, rheolytic therapy, aspiration or catheter-directed thrombolysis. Strengths, challenges and the level of evidence of each device were evaluated. We found 16 different catheter-based therapies for acute PE; all but one being used off-label. The majority of procedures involve catheter-directed thrombolysis. Aspiration therapy shows promise, but limited data are available. Rheolytic therapy should be used with caution, if at all, due to the high number of associated complications.

CONCLUSIONS

Catheter-based therapies show promise as a treatment for acute PE, though evidence is lacking. Further research into the efficacy and safety of devices is needed.

Catheter-Directed Thrombolysis for Pulmonary Embolism: The State of Practice

Acute pulmonary embolism (PE) is a major public health problem. It is the third most common cause of death in hospitalized patients. In the United States, there are up to 600,000 cases diagnosed per year with 100,000-180,000 acute PE-related deaths. Common risk factors include underlying genetic conditions, acquired conditions, and acquired hypercoagulable states. Acute PE increases the pulmonary vascular resistance and the load on the right ventricle (RV). Increased RV loading causes compensatory RV dilation, impaired contractility, tachycardia, and sympathetic activation. RV dilation and increased intramural pressure decrease diastolic coronary blood flow, leading to RV ischemia and myocardial necrosis. Ultimately, insufficient cardiac output from the RV causes left ventricular under-filling which results in systemic hypotension and cardiovascular collapse. Current prognostic stratification strategy separates acute PE into massive, submassive, and low-risk by presence or absence of sustained hypotension, RV dysfunction, and myocardial necrosis. Massive, submassive, and low-risk acute PE have mortality rates of 25%-65%, 3%, and <1%, respectively. Current PE management includes the use of anticoagulation alone, systemic thrombolysis, catheter-directed thrombolysis, and surgical embolectomy. This article will describe the current state of practice for catheter-directed thrombolysis and its role in the management of acute PE.

Unsuccessful percutaneous mechanical thrombectomy in fibrin-rich high-risk pulmonary thromboembolism

Background

We report a case of unsuccessful percutaneous mechanical thrombectomy in treatment of a high-risk pulmonary embolism (PE). Pulmonary thromboemboli are commonly expected as a homogenous mass, rich with red blood cell content, which respond well to percutaneous mechanical thrombectomy (PMT). Catheter-based approach or surgical embolectomy are two treatment options that are usually considered for treatment of high-risk PE when the thrombolytic therapy fails or it is contraindicated due to a patient’s persisting hemodynamic compromise. Currently, selection criteria for PE treatment options are based mostly on the assessment of patient’s history. The aim of this report is to highlight a possible treatment complication in PMT of structurally heterogeneous thrombotic mass due to PMT inadequacy.

Case presentation

A 32 year-old male with polytrauma was admitted to an intensive care unit after a right-sided nephrectomy and evacuation of retroperitoneal hematoma. The patient initial haemostatic disorder was improved by administration of blood preparations, an anti-fibrinolytic agent and concentrates of fibrinogen. On the third day he presented sudden onset of hemodynamic instability and was incapable of standard CTA diagnostic procedure. Urgent and relevant investigations including transthoracic and transesophageal echocardiogram confirmed a high-risk PE. PMT was performed due to contraindications for systemic thrombolysis. Long-term PMT was attempted using aspiration with several devices. No major improvement was achieved in any of the treatments and the patient died. Autopsy confirmed a large heterogeneous thrombotic mass in the pulmonary trunk folding to the right main artery. Additional histological analysis revealed a high fibrin-rich content in the peripheral surroundings of the thrombus.

Conclusion

In the case, it was confirmed that the outcome of PMT was directly influenced by mechanical and histological features of the thromboembolus in high-risk PE. Formation of a rather complex thromboembolus in high-risk PE favors surgical embolectomy as the only life-saving treatment option. Current diagnostic imaging techniques do not enable precise assessment of thrombi structure and are therefore unable to identify patients who might benefit from PMT or open surgical embolectomy. Surgical backup treatment should be considered if there are no contraindications in the event of a failed catheter intervention.

Impact of catheter fragmentation followed by local intrapulmonary thrombolysis in acute high risk pulmonary embolism as primary therapy

BACKGROUND

Pulmonary embolism (PE) with more than 50% compromise of pulmonary circulation results significant right ventricular (RV) afterload leading to progressive RV failure, systemic hypotension and shock. Prompt restoration of thrombolysis, surgical embolectomy, or percutaneous mechanical thrombectomy (PMT) prevents progressive hemodynamic decline. We report our single center experience in high risk PE patients treated with standard pigtail catheter mechanical fragmentation followed by intrapulmonary thrombolysis as a primary therapy.

METHODS

50 consecutive patients with diagnosis of high risk PE defined as having shock index >1 with angiographic evidence of >50% pulmonary arterial occlusion are included in the present study. All patients underwent emergent cardiac catheterization. After ensuring flow across pulmonary artery with mechanical breakdown of embolus by rotating 5F pigtail catheter; bolus dose of urokinase (4400 IU/kg) followed by infusion for 24 h was given in the thrombus. Hemodynamic parameters were recorded and follow up pulmonary angiogram was done. Clinical and echo follow up was done for one year.

RESULTS

Pigtail rotational mechanical thrombectomy restored antegrade flow in all patients. The mean pulmonary artery pressure, Miller score, Shock index decreased significantly from 41 ± 8 mmHg, 20 ± 5, 1.32 ± 0.3 to 24.52 ± 6.89, 5.35 ± 2.16, 0.79 ± 0.21 respectively (p < 0.0001). In-hospital major complications were seen in 4 patients. There was a statistically significant reduction of PA pressures from 62 ± 11 mmHg to 23±6 mmHg on follow up.

CONCLUSIONS

Rapid reperfusion of pulmonary arteries with mechanical fragmentation by pigtail catheter followed by intrapulmonary thrombolysis results in excellent immediate and intermediate term outcomes in patients presenting with high risk pulmonary embolism.

Mechanical breakdown and thrombolysis in subacute massive pulmonary embolism: A prospective trial

AIM: To assess role of combined modality of mechanical fragmentation and intralesional thrombolysis in patients with massive pulmonary embolism presenting subacutely.

METHODS: Eight of 70 patients presenting in tertiary care centre of North India with massive pulmonary embolism within 4 years had subacute presentation (symptom onset more than 2 wk). These patients were subjected to pulmonary angiography with intention to treat basis via mechanical breakdown and intra lesional thrombolysis. Mechanical breakdown of embolus was accomplished with 5-F multipurpose catheter to re-establish flow, followed by intralesional infusion of urokinase (4400 IU/kg over 10 min followed by 4400 IU/kg per hour over 24 h).

RESULTS: Eight patients, mean age 47.77 ± 12.20 years presented with subacute pulmonary embolism (mean duration of symptoms 2.4 wk). At presentation, mean heart rate, shock index, miller score and mean pulmonary pressures were 101.5 ± 15.2/min, 0.995 ± 0.156, 23.87 ± 3.76 and 37.62 ± 6.67 mmHg which reduced to 91.5 ± 12.2/min (P = 0.0325), 0.789 ± 0.139 (P = 0.0019), 5.87 ± 1.73 (P = 0.0000004) and 27.75 ± 8.66 mmHg (P = 0.0003) post procedurally. Mean BP improved from 80.00 ± 3.09 mmHg to 90.58 ± 9.13 mmHg (P = 0.0100) post procedurally. Minor complications in the form of local hematoma-minor hematoma in 1 (12.5%), and pseudoaneurysm (due to femoral artery puncture) in 1 (12.5 %) patient were seen. At 30 d and 6 mo follow up survival rate was 100% and all the patients were asymptomatic and in New York Heart Association class 1.

CONCLUSION: Combined modality of mechanical fragmentation and intralesional thrombolysis appears to be a promising alternative to high risk surgical procedures in patients with subacute massive pulmonary embolism.

Evaluation of computed tomography obstruction index in guiding therapeutic decisions and monitoring percutanous catheter fragmentation in massive pulmonary embolism

In the present study, we evaluated computed tomography pulmonary angiography (CTPA) in guiding therapeutic decisions and monitoring patients undergoing percutaneous catheter fragmentation in acute massive pulmonary embolism. From Jan 2003 to Dec 2009, 35 patients were diagnosed with acute massive pulmonary embolism by CTPA (T0) and treated with percutaneous catheter fragmentation. The severity was assessed by CT obstruction index (Qanadli index) and compared with Miller index. CTPA, oxygen saturation (SaO2) and pulmonary artery pressure were performed as follow-up index. The mean percentage of Qanadli index was (55±13)% (range, 40%-75%), and Miller index was (62±15)% (range, 45%-85%). Correlations between them were statistically significant (r = 0.867, P < 0.0001). The Qanadli index showed significant reduction [T0: (55±13)%; T1: (12±10)%; P < 0.001] in 33 patients. Significant correlation was observed between the Qanadli index, SaO2 (r = 0.934), and pulmonary artery pressure (r = 0.813). The Qanadli index provides an accurate method for distinguishing massive pulmonary embolism from sub-massive pulmonary embolism. It can be used to determine therapeutic options and monitor clinical outcomes.

Antithrombotic therapy for VTE disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

This article addresses the treatment of VTE disease.

METHODS

We generated strong (Grade 1) and weak (Grade 2) recommendations based on high-quality (Grade A), moderate-quality (Grade B), and low-quality (Grade C) evidence.

RESULTS

For acute DVT or pulmonary embolism (PE), we recommend initial parenteral anticoagulant therapy (Grade 1B) or anticoagulation with rivaroxaban. We suggest low-molecular-weight heparin (LMWH) or fondaparinux over IV unfractionated heparin (Grade 2C) or subcutaneous unfractionated heparin (Grade 2B). We suggest thrombolytic therapy for PE with hypotension (Grade 2C). For proximal DVT or PE, we recommend treatment of 3 months over shorter periods (Grade 1B). For a first proximal DVT or PE that is provoked by surgery or by a nonsurgical transient risk factor, we recommend 3 months of therapy (Grade 1B; Grade 2B if provoked by a nonsurgical risk factor and low or moderate bleeding risk); that is unprovoked, we suggest extended therapy if bleeding risk is low or moderate (Grade 2B) and recommend 3 months of therapy if bleeding risk is high (Grade 1B); and that is associated with active cancer, we recommend extended therapy (Grade 1B; Grade 2B if high bleeding risk) and suggest LMWH over vitamin K antagonists (Grade 2B). We suggest vitamin K antagonists or LMWH over dabigatran or rivaroxaban (Grade 2B). We suggest compression stockings to prevent the postthrombotic syndrome (Grade 2B). For extensive superficial vein thrombosis, we suggest prophylactic-dose fondaparinux or LMWH over no anticoagulation (Grade 2B), and suggest fondaparinux over LMWH (Grade 2C).

CONCLUSION

Strong recommendations apply to most patients, whereas weak recommendations are sensitive to differences among patients, including their preferences.

Endovascular therapy for acute pulmonary embolism

Acute pulmonary embolism (PE) is the third most common cause of death among hospitalized patients. Treatment escalation beyond anticoagulation therapy is necessary in patients with massive PE (defined by hemodynamic shock) as well as in many patients with submassive PE (defined by right ventricular strain). The best current evidence suggests that modern catheter-directed therapy to achieve rapid central clot debulking should be considered as an early or first-line treatment option for patients with acute massive PE; and emerging evidence suggests a catheter-directed thrombolytic infusion should be considered as adjunctive therapy for many patients with acute submassive PE. This article reviews the current approach to endovascular therapy for acute PE in the context of appropriate diagnosis, risk stratification, and management of acute massive and acute submassive PE.

Interventional treatment of venous thromboembolism: a review

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is the third most common cardiovascular disease after coronary artery disease and cerebrovascular disease and is responsible for significant morbidity and mortality in the general population. Full dose anticoagulation is the standard therapy for VTE, both for the acute and the long-term phase. The latest guidelines of the American College of Chest Physicians recommend treatment with a full-dose of unfractioned heparin (UFH), low-molecular-weight-heparin (LMWH), fondaparinux, vitamin K antagonist (VKA) or thrombolysis for most patients with objectively confirmed VTE. Catheter-guided thrombolysis and trombosuction are interventional approaches that should be used only in selected populations; interruption of the inferior vena cava (IVC) with a filter can be performed to prevent life-threatening PE in patients with VTE and contraindications to anticoagulant treatment, bleeding complications during antithrombotic treatment, or VTE recurrences despite optimal anticoagulation. In this review we summarize the currently available literature regarding interventional approaches for VTE treatment (vena cava filters, catheter-guided thrombolysis, thrombosuction) and we discuss current evidences on their efficacy and safety. Moreover, the appropriate indications for their use in daily clinical practice are reviewed.

Treatment of pulmonary embolism: anticoagulation, thrombolytic therapy, and complications of therapy

During the last two decades, considerable progress in technology and clinical research methods have led to advances in the approach to the diagnosis, prevention, and treatment of acute venous thromboembolism (VTE). Despite this, however, the diagnosis is often delayed and preventive methods are often ignored. Thus, the morbidity and mortality associated with VTE remain high. The therapeutic approach to acute VTE is discussed in this article, with a particular focus on the intensive care unit setting.

Interventional therapies for venous thromboembolism: vena caval interruption, surgical embolectomy, and catheter-directed interventions

Therapeutic strategies other than anticoagulation sometimes require consideration in the setting of acute venous thromboembolism. Vena caval filter placement is increasingly common, in part because of the availability of nonpermanent filter devices. Filter placement, surgical embolectomy, and catheter embolectomy have not been subjected to the same prospective, randomized clinical trial scrutiny as anticoagulation but seem appropriate in certain clinical settings. The indications, contraindications, and available data supporting these therapeutic methods are discussed.

Massive pulmonary embolism: treatment with the rotarex thrombectomy system

This study was designed to evaluate the efficacy and safety of percutaneous mechanical thrombectomy (PMT) for acute massive pulmonary embolism (PE). Fourteen patients (8 men, 6 women) with a mean age of 55.4 (range, 38-71) years with acute massive PE were initially diagnosed by computed tomography (CT) and confirmed by pulmonary angiography. All patients presented with acute PE symptoms and hemodynamic compromise. Each patient was treated with Straub Rotarex thrombectomy device and five patients received additional thrombolysis. Technique success and clinical improvement were achieved in all patients without major complications. The mean pulmonary artery pressure (PAP) decreased from 37.6 ± 6.6 to 29 ± 6.4 mmHg (P < 0.01) after PMT. Partial arterial pressures of O(2) (PaO(2)) increased from 61.1 ± 9.2 to 88 ± 5.1 mmHg (P < 0.01). The Miller index was 0.67 ± 0.11 and 0.37 ± 0.13 (P < 0.01), respectively, before and after PMT (P < 0.01). Eleven patients had no recurrence of PE on a mean follow-up of 28.3 months, whereas the other three patients were lost to follow-up. The preliminary experience in our series suggests that the Straub Rotarex thrombectomy device, which has been utilized in peripheral arteries, also is useful for the treatment of acute massive PE.

Catheter-directed therapy for the treatment of massive pulmonary embolism: systematic review and meta-analysis of modern techniques

PURPOSE

Systemic thrombolysis for the treatment of acute pulmonary embolism (PE) carries an estimated 20% risk of major hemorrhage, including a 3%-5% risk of hemorrhagic stroke. The authors used evidence-based methods to evaluate the safety and effectiveness of modern catheter-directed therapy (CDT) as an alternative treatment for massive PE.

MATERIALS AND METHODS

The systematic review was initiated by electronic literature searches (MEDLINE, EMBASE) for studies published from January 1990 through September 2008. Inclusion criteria were applied to select patients with acute massive PE treated with modern CDT. Modern techniques were defined as the use of low-profile devices (< or =10 F), mechanical fragmentation and/or aspiration of emboli including rheolytic thrombectomy, and intraclot thrombolytic injection if a local drug was infused. Relevant non-English language articles were translated into English. Paired reviewers assessed study quality and abstracted data. Meta-analysis was performed by using random effects models to calculate pooled estimates for complications and clinical success rates across studies. Clinical success was defined as stabilization of hemodynamics, resolution of hypoxia, and survival to hospital discharge.

RESULTS

Five hundred ninety-four patients from 35 studies (six prospective, 29 retrospective) met the criteria for inclusion. The pooled clinical success rate from CDT was 86.5% (95% confidence interval [CI]: 82.1%, 90.2%). Pooled risks of minor and major procedural complications were 7.9% (95% CI: 5.0%, 11.3%) and 2.4% (95% CI: 1.9%, 4.3%), respectively. Data on the use of systemic thrombolysis before CDT were available in 571 patients; 546 of those patients (95%) were treated with CDT as the first adjunct to heparin without previous intravenous thrombolysis.

CONCLUSIONS

Modern CDT is a relatively safe and effective treatment for acute massive PE. At experienced centers, CDT should be considered as a first-line treatment for patients with massive PE.

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.

Catheter-directed embolectomy, fragmentation, and thrombolysis for the treatment of massive pulmonary embolism after failure of systemic thrombolysis

PURPOSES

The standard medical management for patients in extremis from massive pulmonary embolism (PE) is systemic thrombolysis, but the utility of this treatment relative to catheter-directed intervention (CDI) is unknown. We evaluated the effectiveness of CDI as part of a treatment algorithm for life-threatening PE.

METHODS

A retrospective review was performed on 70 consecutive patients with suspected acute PE over a 10-year period (from 1997 to 2006) who had been referred for pulmonary angiography and/or intervention. The criteria for study inclusion were patients who received CDI due to angiographically confirmed massive PE and hemodynamic shock (shock index, > or = 0.9). CDI involved suction embolectomy and fragmentation with or without catheter thrombolysis.

RESULTS

Twelve patients were treated with CDI. There were seven men and five women (mean age, 56 years; age range, 21 to 80 years). Seven patients (58%) were referred for CDI after failing systemic infusion with 100 mg of tissue plasminogen activator, and five patients (42%) had contraindications to systemic thrombolysis. Catheter-directed fragmentation and embolectomy were performed in all patients (100%). Additionally, catheter-guided thrombolysis was performed in eight patients (67%). Technical success was achieved in 12 of 12 cases (100%). There were no major procedural complications (0%). Significant hemodynamic improvement (shock index, < 0.9) was observed in 10 of 12 cases (83%). The remaining two patients (17%) died secondary to cardiac arrest within 24 h. Ten of 12 patients (83%) survived and remained stable until hospital discharge (mean duration, 20 days; range, 3 to 51 days).

CONCLUSION

In the setting of hemodynamic shock from massive PE, CDI is potentially a life-saving treatment for patients who have not responded to or cannot tolerate systemic thrombolysis.

Antithrombotic therapy for venous thromboembolic disease: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

This chapter about treatment for venous thromboembolic disease is part of the American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Grade 1 recommendations are strong and indicate that the benefits do or do not outweigh risks, burden, and costs. Grade 2 suggests that individual patient values may lead to different choices (for a full understanding of the grading, see "Grades of Recommendation" chapter). Among the key recommendations in this chapter are the following: for patients with objectively confirmed deep vein thrombosis (DVT) or pulmonary embolism (PE), we recommend anticoagulant therapy with subcutaneous (SC) low-molecular-weight heparin (LMWH), monitored IV, or SC unfractionated heparin (UFH), unmonitored weight-based SC UFH, or SC fondaparinux (all Grade 1A). For patients with a high clinical suspicion of DVT or PE, we recommend treatment with anticoagulants while awaiting the outcome of diagnostic tests (Grade 1C). For patients with confirmed PE, we recommend early evaluation of the risks to benefits of thrombolytic therapy (Grade 1C); for those with hemodynamic compromise, we recommend short-course thrombolytic therapy (Grade 1B); and for those with nonmassive PE, we recommend against the use of thrombolytic therapy (Grade 1B). In acute DVT or PE, we recommend initial treatment with LMWH, UFH or fondaparinux for at least 5 days rather than a shorter period (Grade 1C); and initiation of vitamin K antagonists (VKAs) together with LMWH, UFH, or fondaparinux on the first treatment day, and discontinuation of these heparin preparations when the international normalized ratio (INR) is > or = 2.0 for at least 24 h (Grade 1A). For patients with DVT or PE secondary to a transient (reversible) risk factor, we recommend treatment with a VKA for 3 months over treatment for shorter periods (Grade 1A). For patients with unprovoked DVT or PE, we recommend treatment with a VKA for at least 3 months (Grade 1A), and that all patients are then evaluated for the risks to benefits of indefinite therapy (Grade 1C). We recommend indefinite anticoagulant therapy for patients with a first unprovoked proximal DVT or PE and a low risk of bleeding when this is consistent with the patient's preference (Grade 1A), and for most patients with a second unprovoked DVT (Grade 1A). We recommend that the dose of VKA be adjusted to maintain a target INR of 2.5 (INR range, 2.0 to 3.0) for all treatment durations (Grade 1A). We recommend at least 3 months of treatment with LMWH for patients with VTE and cancer (Grade 1A), followed by treatment with LMWH or VKA as long as the cancer is active (Grade 1C). For prevention of postthrombotic syndrome (PTS) after proximal DVT, we recommend use of an elastic compression stocking (Grade 1A). For DVT of the upper extremity, we recommend similar treatment as for DVT of the leg (Grade 1C). Selected patients with lower-extremity (Grade 2B) and upper-extremity (Grade 2C). DVT may be considered for thrombus removal, generally using catheter-based thrombolytic techniques. For extensive superficial vein thrombosis, we recommend treatment with prophylactic or intermediate doses of LMWH or intermediate doses of UFH for 4 weeks (Grade 1B).

Chronic pulmonary thromboembolism in a patient with a fontan circulation: percutaneous management

Chronic pulmonary embolism is a common complication in patients with Fontan circulations. When anticoagulation is ineffective and surgery is contraindicated, percutaneous techniques may be considered. The authors report the first case of successful catheter intervention in a 30-year-old woman with a Fontan circulation who presented with NYHA class IV symptoms and chronic and complete obstruction of her left pulmonary artery.

Non-cardiac surgery applications of extracorporeal circulation

Although the efficacy of extracorporeal circulation (ECC) is well established for open-heart surgery, application of ECC in other surgical areas has not been given much attention. Advances in the related surgical technique and anesthetic management combined with refinements in the ECC procedure itself have encouraged several institutions to use ECC for complex non-cardiac surgeries. ECC is beginning to be used for circulatory support or tissue oxygenation during surgery on the lung, brain, liver, and kidney as well as in emergency situations. With ECC, difficult and complex surgeries can be performed more safely, and the success rate of certain surgeries has been positively affected. It is important that the surgeon, anesthesiologist, and perfusionist are trained in non-cardiac surgery applications of ECC. Thus, we review here non-cardiac uses that have emerged and summarize the related procedures.

Catheter Embolectomy for Acute Pulmonary Embolism

Massive pulmonary embolism (PE) is a life-threatening condition with a high early mortality rate due to acute right ventricular failure and cardiogenic shock. As soon as the diagnosis is suspected, an IV bolus of unfractionated heparin should be administered. In addition to anticoagulation, rapid initiation of systemic thrombolysis is potentially life-saving and therefore is standard therapy. Many patients with massive PE cannot receive thrombolysis because of an increased bleeding risk, such as prior surgery, trauma, or cancer. In these patients, catheter or surgical embolectomy are helpful for rapidly reversing right ventricular failure. Catheter thrombectomy appears to be particularly useful if surgical embolectomy is not available or the patient has contraindications to surgery. Although no controlled clinical trials are available, data from cohort studies indicate that the clinical outcomes after surgical and catheter embolectomy may be comparable.

Pulmonary Embolism in the Critically Ill

Pulmonary embolism in the critically ill requires considerations beyond anticoagulant therapy. Measurements of chamber size by echocardiography and CT and of circulating biomarkers identify higher-risk patients with moderate accuracy and may aid determination of patient acuity. Preserving right ventricular function requires judicious use of volume administration, vasopressor, and perhaps vasodilator therapies. Obstructing thrombus can be treated with fibrinolytic drugs, percutaneous instrumentation, or surgically, but these treatments may not be equally effective or safe. Anticoagulant therapy in critically ill patients is likely best administered IV. Bleeding complications should be assiduously sought but do not necessitate anticoagulant discontinuation in every case. The antidotes protamine, desmopressin acetate, factor VIII inhibitory bypass activity, and recombinant factor VIIa may each have a place in controlling anticoagulant-related bleeding. The grave prognosis of heparin-induced thrombocytopenia warrants close surveillance, with rapid switching to lepirudin, argatroban, or fondaparinux necessary if it is suspected. Retrievable vena cava filters can be lifesaving, and at least one type may be safely removed after residence of nearly 1 year.

Extracorporeal Life Support for Massive Pulmonary Embolism

BACKGROUND

Massive pulmonary embolism is frequently lethal because of acute irreversible pulmonary and cardiac failure. Extracorporeal life support (ECLS) has been used for cardiopulmonary failure in our institution since 1988, and we reviewed our experience with its use in the management of massive pulmonary emboli.

METHODS

We reviewed our complete experience with ECLS for massive pulmonary emboli from January 1992 through December 2005. The records of 21 patients were examined and data extracted.

RESULTS

During the study period, 21 patients received ECLS for massive pulmonary emboli. All patients were on vasoactive drugs, acidemic, and hypoxic at the time of institution of ECLS. Eight were in active cardiac arrest. Five were trauma patients, eight had recently undergone an operation, and six had a hypercoagulable disorder. Nineteen of the 21 patients were cannulated for venoarterial bypass and two were placed on venovenous bypass. The average duration of support for survivors was 5.4 days, ranging from 5 hours to 12.5 days. Emboli resolved with anticoagulation in 10 of 13 survivors and 4 of 13 survivors underwent surgical pulmonary embolectomy. Catastrophic neurologic events were the most common cause of mortality in our series; four patients died from intracranial hemorrhage. The overall survival rate was 62% (13/21).

CONCLUSIONS

We conclude that emergent ECLS provides an opportunity to improve the prognosis of an otherwise near-fatal condition, and should be considered in the algorithm for management of a massive pulmonary embolism in an unstable patient.

Catheter-tip embolectomy in the management of acute massive pulmonary embolism

Three catheter interventional techniques are currently available for removing or fragmenting pulmonary emboli: aspiration thrombectomy, fragmentation, and rheolytic thrombectomy. The investigators systematically reviewed all available published research related to the use of catheter-tip devices in patients with pulmonary emboli. Pooled data showed that clinical success with the Greenfield catheter occurred in 72 of 89 patients (81%) when used alone and in 19 of 19 patients (100%) when used in combination with thrombolytic agents. Fragmentation with standard catheters used alone (without thrombolytic agents) was reported in only 3 patients. Clinical success with standard angiographic catheters occurred in 15 of 21 patients (71%) when used in combination with systemic thrombolytic agents and in 115 of 121 patients (95%) when used with local infusions of thrombolytic agents. Data for the Amplatz catheter, the rheolytic Angiojet catheter, and the Hydrolyser catheter when used alone were sparse or absent. Clinical success when used in combination with thrombolytic agents occurred in 6 of 6 patients (100%) with the Amplatz catheter, in 20 of 23 patients (87%) with the Angiojet catheter, and in 19 of 20 patients (95%) with the Hydrolyser catheter. Minor bleeding at the insertion site among all patients, with and without thrombolytic agents, occurred in 29 of 348 patients (8%), and major bleeding at the insertion site occurred in 8 of 348 patients (2%). One patient experienced perforation of the right ventricle with the Greenfield catheter. None reported perforation of a pulmonary artery. In conclusion, all the devices analyzed in this study appear to be useful in the management of acute massive pulmonary emboli.

Novel percutaneous catheter thrombectomy in acute massive pulmonary embolism: rotational bidirectional thrombectomy (ROBOT)

BACKGROUND

Although thrombolysis is a standard therapy in cases of pulmonary embolism (PE), fatal outcome is often observed. We designed and investigated the efficacy of a novel percutaneous catheter therapy, rotational bidirectional thrombectomy (ROBOT), for PE.

METHODS AND RESULTS

Eighteen patients with acute massive PE (Miller score > or = 20) were included in this study. We separated them into two groups [group A (n = 10), thrombolysis; group B (n = 8): thrombolysis and ROBOT or ROBOT alone]. There was no difference in the hemodynamic indices between the groups at diagnosis. ROBOT was designed to fragment emboli by rotating a regular pigtail catheter. Three deaths occurred in group A because of hemodynamic impairment, but there was no death in group B. One day after treatment, systolic pulmonary artery pressure had decreased from 53 +/- 8 to 30 +/- 8 mm Hg (P < 0.05) in group B and from 54 +/- 5 to 42 +/- 19 mm Hg (NS) in group A. The hospitalization period in group B was shorter than that in group A (17 +/- 6 vs. 27 +/- 10 days, P < 0.05).

CONCLUSION

ROBOT therapy results in a significant, rapid improvement in the hemodynamic situation and in a better outcome than conventional therapy in patients with acute massive pulmonary embolism.

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.

Treatment of Acute Pulmonary Embolism: Local Effects of Three Hydrodynamic Thrombectomy Devices in an Ex Vivo Porcine Model

PURPOSE

To report an ex vivo study on the local effects of hydrodynamic thrombectomy for the treatment of acute pulmonary embolism (off-label use).

METHODS

Three devices (6-F AngioJet Xpeedior and 6-F and 8-F Oasis) were used for hydrodynamic thrombectomy inside the arteries of 24 inflated and perfused porcine lung explants. Each system was used at multiple positions inside 4 intact and 4 embolized lungs in vessels measuring 2 to 4 mm, 4 to 6 mm, 6 to 8 mm, and 8 to 10 mm. Angiograms prior to, during, and after catheter positioning and system operation were used to detect arterial wall trauma and to measure local clot removal per 30-second cycle. A total of 21 vessel wall samples were subjected to scanning electron microscopy (SEM) to evaluate non-perforating lesions.

RESULTS

All systems were able to remove clot material. The average recanalized vessel length normalized to 30 seconds for vessel diameters of 2 to 4 and 8 to 10 mm, respectively, was 1.17 and 1.75 cm (AngioJet), 0.97 and 0.25 cm (6-F Oasis), and 2.2 and 1.05 cm (8-F Oasis). Perforations occurred during positioning of the 6-F Oasis (4/78 maneuvers) and 8-F Oasis (13/60), but not the AngioJet (0/89); perforations were also seen during system operation (AngioJet: 21/89 activations, 6-F Oasis: 4/78, and 8-F Oasis: 9/60; all lesions inside vessels <6 mm in diameter). SEM showed 35 lesions, 14 with perforation (contrast extravasation) and 21 without perforation (induced by the tip of the guidewire).

CONCLUSION

The AngioJet was most efficient in clot removal, followed by the 8-F Oasis. The 6-F Oasis was least efficient, but had fewest complications. According to these experiments, the tested hydrodynamic thrombectomy devices may cause perforations in vessels <6 mm in diameter. Changes in catheter design to reduce system-specific complication rates or to improve the efficacy of clot removal are warranted.

When should we thrombolyse patients with pulmonary embolism? A systematic review of the literature

The early mortality in pulmonary embolism (PE) is largely predicted by the associated cardiovascular response, with progressive right ventricular failure, hypotension, shock, and circulatory arrest being associated with increasing mortality. Thrombolysis may improve the prognosis of PE associated with these varying degrees of circulatory collapse, but has no place in the treatment of small emboli with no cardiovascular compromise, as it carries a significant risk of haemorrhage. This review sets out to guide the emergency physician in deciding which patients with PE may benefit from thrombolysis.

Percutaneous Catheter Thrombectomy Device for Acute Pulmonary Embolism: In Vitro and in Vivo Testing

PURPOSE

To evaluate a percutaneous pulmonary embolism (PE) thrombectomy catheter that aspirates, macerates, and removes thrombus.

MATERIALS AND METHODS

Nine in vitro tests were performed by using porcine thrombi at a PE test station that provides continuous fluid output of 2 L/min at a pressure of 50 mmHg. Macroembolization was defined as embolized particles larger than 1.5 mm in dimension; microembolization was defined as particles that range in size from 0.1 to 1.5 mm. In static in vitro tests, researchers measured plasma-free hemoglobin levels in a 36-year-old man to assess mechanical hemolysis. Investigational review board approval and informed consent were obtained. The Department of Agriculture, Veterinary Bureau, Bern, Switzerland approved in vivo tests. Researchers investigated device effectiveness in 10 pigs that developed cardiogenic shock but survived massive PE after injection of two or three porcine thrombi into the external jugular vein via a surgically implanted 24-F sheath. Pulmonary angiography and hemodynamic measurements, including mean aortic and mean pulmonary artery pressure, heart rate, and mixed venous oxygen saturation, were obtained at baseline, after embolization, and after thrombectomy. Repeated-measures analysis of variance was performed to compare hemodynamic measurements at baseline, after embolization, and after thrombectomy. Cardiovascular structures were examined at necropsy for rupture, perforation, dissection, or hemorrhage.

RESULTS

During a mean aspiration time of 69 seconds +/- 19, thrombi were completely extracted from 14-mm test tubes, with an aspirated fluid volume of 201 mL +/- 64. Although no macroembolization was observed, microembolization was quantified at 1.9 g +/- 1.3. Catheter aspiration was not associated with an increase in plasma-free hemoglobin. In 10 animals, aortic pressure increased from 52 mmHg +/- 24 before thrombectomy to 90 mmHg +/- 32 after thrombectomy, mixed venous oxygen saturation increased from 48% +/- 19% to 61% +/- 12%, pulmonary artery pressure decreased from 33 mmHg +/- 9 to 22 mmHg +/- 4, and heart rate decreased from 162 beats per minute +/- 24 to 114 beats per minute +/- 14. We did not observe macro- or microscopic damage to treated or untreated cardiovascular structures.

CONCLUSION

The PE thrombectomy device was highly effective, facilitating rapid reversal of cardiogenic shock without device-related complications.

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.