A new treatment for severe pulmonary embolism: percutaneous rheolytic thrombectomy

Mechanical Circulatory Support to Treat Pulmonary Embolism: Venoarterial Extracorporeal Membrane Oxygenation and Right Ventricular Assist Devices

Mechanical circulatory support may help patients with massive pulmonary embolism who are not candidates for systemic thrombolysis, pulmonary embolectomy, or catheter-directed therapy, or in whom these established interventions have failed. Little published literature covers this topic, which led us to compare outcomes of patients whose massive pulmonary embolism was managed with the use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) or a right ventricular assist device (RVAD). We searched the medical literature from January 1990 through September 2018 for reports of adults hospitalized for massive or high-risk pulmonary embolism complicated by hemodynamic instability, and who underwent VA-ECMO therapy or RVAD placement. Primary outcomes included weaning from mechanical circulatory support and discharge from the hospital. We found 16 reports that included 181 patients (164 VA-ECMO and 17 RVAD). All RVAD recipients were successfully weaned from support, as were 122 (74%) of the VA-ECMO patients. Sixteen (94%) of the RVAD patients were discharged from the hospital, as were 120 (73%) of the VA-ECMO patients. Of note, the 8 RVAD patients who had an Impella RP System were all weaned and discharged. For patients with massive pulmonary embolism who are not candidates for conventional interventions or whose conditions are refractory, mechanical circulatory support in the form of RVAD placement or ECMO may be considered. Larger comparative studies are needed.

Concise Review of the Clinical Approach to the Exclusion and Diagnosis of Pulmonary Embolism in 2020

Pulmonary embolism has extremely varied clinical presentations and can be difficult to diagnose. Clinical decision rules can help determine the probability of pulmonary embolism by assessment of the clinical presentation. After the diagnosis, several prognostic rules can be used to risk-stratify and facilitate outpatient treatment of pulmonary embolism. This review addresses the utility of clinical decision rules, biomarkers in the diagnosis of pulmonary emoblism, high-risk patient phenotypes, the use of this data to make disposition decisions for patients with a diagnosis of PE, and recent shifts in the management of pulmonary embolism in the clinical setting.

[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.

Angiojet rheolytic thrombectomy combined with catheter fragmentation in a patient presenting with massive pulmonary embolism and cardiogenic shock

Massive pulmonary embolism (MPE) is associated with a high rate of mortality, and chronic thromboembolic pulmonary hypertension leads to ongoing morbidity among many survivors. Here we report a case of a MPE successfully treated by Angiojet rheolytic thrombectomy combined with catheter fragmentation. This is the first report of the use of these two methods together for MPE treatment.

Management of massive and submassive pulmonary embolism

Massive pulmonary embolism has a high mortality rate despite advances in diagnosis and therapy. This article attempts to review the evidence-based risk stratification, diagnosis, initial stabilization, and management of massive and submassive pulmonary embolism.

Management of peripheral pulmonary emboli with the use of transvenous catheter-directed thrombolysis and right ventricular assist device

OBJECTIVES

Pulmonary emboli (PE) can result in significant hemodynamic instability that requires urgent intervention; however, the management of peripheral emboli has been controversial.

PATIENTS AND METHODS

We present two patients in whom a right ventricular assist device (RVAD) was used in treating peripheral pulmonary embolism, applying the technique of pulmonary artery catheter-directed thrombolysis after resuscitation with an RVAD.

RESULTS

The clot burden was not suitable for surgical embolectomy due to its peripheral locations. The patients' hemodynamic conditions improved with thrombolytic therapy and gradually were weaned off the RVAD. Follow-up scans showed near resolution of all PE.

CONCLUSION

Catheter-directed thrombolysis with an RVAD as an adjunct should be considered in management of peripheral PE.

Management of massive and nonmassive pulmonary embolism

Massive pulmonary embolism (PE) is characterized by systemic hypotension (defined as a systolic arterial pressure < 90 mm Hg or a drop in systolic arterial pressure of at least 40 mm Hg for at least 15 min which is not caused by new onset arrhythmias) or shock (manifested by evidence of tissue hypoperfusion and hypoxia, including an altered level of consciousness, oliguria, or cool, clammy extremities). Massive pulmonary embolism has a high mortality rate despite advances in diagnosis and therapy. A subgroup of patients with nonmassive PE who are hemodynamically stable but with right ventricular (RV) dysfunction or hypokinesis confirmed by echocardiography is classified as submassive PE. Their prognosis is different from that of others with non-massive PE and normal RV function. This article attempts to review the evidence-based risk stratification, diagnosis, initial stabilization, and management of massive and nonmassive pulmonary embolism.

Right axillosubclavian vein thrombosis resolved by percutaneous rheolytic thrombectomy in a patient with a recurrent gastrointestinal stromal tumour undergoing imatinib mesylate treatment

The manifestation and management of spontaneous axillosubclavian vein thrombosis in patients with gastrointestinal stromal tumour (GIST) undergoing oral chemotherapy have never been described. We report a patient with a recurrent GIST who was receiving maintenance imatinib yet developed a right axillosubclavian vein thrombotic occlusion. The occluded vein was unresponsive to systemic anticoagulation but was reopened by percutaneous rheolytic thrombectomy and has shown good long-term patency. Thus, for patients with recurrent GIST undergoing imatinib therapy, axillosubclavian vein thrombosis might manifest as a complication and could be managed with rheolytic thrombectomy, which thoroughly removes intravascular thrombus and effectively re-vascularizes the thrombosed vessel uneventfully.

Rheolytic Thrombectomy with or without Adjunctive Indwelling Pharmacolysis in Patients Presenting with Acute Pulmonary Embolism Presenting with Right Heart Strain and/or Pulseless Electrical Activity

Purpose. To evaluate the safety and efficacy of the Possis rheolytic thrombectomy with or without indwelling catheter-directed pharmacolysis for the treatment of massive pulmonary embolus in patients presenting with right heart strain and/or a pulseless electrical activity (PEA). Materials and Methods. Retrospective review of patients undergoing pulmonary pharmacolysis was performed (07/2004-06/2009). Pre- and posttreatment Miller index scoring weres calculated and compared. Patients were evaluated for tPA doses, ICU stay, hospital stay, and survival by Kaplan-Meier analysis. Results. 11 patients with massive PE were found, with 10/11 presenting with a Miller score of >17 (range: 16-27, mean: 23.2). CTPA and/or echocardiographic evidence of right heart strain was found in 10/11 patients. 3 (27%) patients presented with a PEA event. Two (18%) patients had a contraindication to pharmacolysis and were treated with mechanical thrombectomy alone. The intraprocedural mortality was 9% (n = 1/11). Of the 10 patients who survived the initial treatment, 7 patients underwent standard mechanical thrombectomy initially, while 5 received power pulse spray mechanical thrombectomy. Eight of these 10 patients underwent adjunctive indwelling catheter-directed thrombolysis. The mean catheter-directed infusion duration was 18 hours (range of 12-26 hours). The average intraprocedural, infusion, and total doses of tPA were 7 mg, 19.7 mg, and 26.7 mg, respectively. There was a 91% (10/11) technical success rate. The failure was the single mortality. Average reduction in Miller score was 9.5 or 41% (P = 0.009), obstructive index of 6.4 or 47% (P = 0.03), and perfusion index of 2.7 or 28% (P = 0.05). Average ICU and hospital stay were 7.4 days (range 2-27 days) and 21.3 days (range 6-60 days), respectively. Intent to treat survival was 90% at 6, 12, and 18 months. Conclusion. Rheolytic thrombectomy with or without adjunctive catheter-directed thrombolysis provides a safe and effective method for treatment of acute PE in patients who present with right heart strain and/or a PEA event.

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.

Successful percutaneous mechanical thrombectomy in a haemodynamically unstable patient with massive pulmonary embolism

Massive pulmonary embolism with haemodynamic instability has a high mortality. Traditionally these patients are treated with i.v. thrombolytic therapy. When this therapeutic approach is contraindicated, surgical embolectomy and most recently, percutaneous mechanical interventions are alternative treatment options. This case report presents a 73-year-old female with a residual hemiparesis secondary to a meningioma resection 45 days previously, who presented with progressive shortness of breath, accompanied by oppressive chest pain, hypotension, tachycardia and severe hypoxaemia. CT pulmonary angiogram confirmed a massive pulmonary embolism extending into the lobar branches bilaterally. The patient was treated with percutaneous mechanical thrombectomy with excellent haemodynamic and clinical outcomes.

Rheolytic thrombectomy in patients with massive and submassive acute pulmonary embolism

OBJECTIVES

To appraise the impact of AngioJet rheolytic thrombectomy (RT) on angiographic and clinical endpoints in patients with acute pulmonary embolism (PE).

BACKGROUND

The management of patients with acute PE and hemodynamic compromise, based mainly on anticoagulant and thrombolytic therapies, is challenging and still suboptimal in many patients. In such a setting, mechanical removal of thrombus from pulmonary circulation holds the promise of significant clinical benefits, albeit remains under debate.

METHODS

We retrospectively report on 51 patients referred to our catheterization laboratory and treated with AngioJet RT. Patients were classified according to the degree of hemodynamic compromise (shock, hypotension, and right ventricular dysfunction) to explore thoroughly the degree of angiographic pulmonary involvement (angiographic massive PE was defined as the presence of a Miller index >or= 17) and the impact on angiographic (obstruction, perfusion, and Miller indexes) and clinical (all-cause death, recurrence of PE, bleeding, renal failure, and severe thrombocytopenia) endpoints of AngioJet RT.

RESULTS

Angiographic massive PE was present in all patients with shock, whereas patients with right ventricular dysfunction and hypotension showed a similar substantial pulmonary vascular bed involvement. Technical success was obtained in 92.2% of patients, with a significant improvement in obstruction, perfusion and Miller indexes in each subgroup (all P < 0.0001). Four patients reported major bleedings and eight (15.7%) died in-hospital. Laboratory experience was significantly associated to a lower rate of major bleedings. All survivors were alive at long-term follow-up (35.5 +/- 21.7 months) except three who expired due to cancer and acute myocardial infarction.

CONCLUSIONS

In experienced hands AngioJet RT can be operated safely and effectively in most patients with acute PE, either massive or submassive, and substantial involvement of pulmonary vascular bed.

Percutaneous mechanical thrombectomy for the treatment of acute massive pulmonary embolism: case report

BACKGROUND

To our knowledge we report the first case of percutaneous mechanical thrombectomy used for the treatment of massive pulmonary embolism in the United Kingdom. Pulmonary embolism is a common disease process but can be difficult to diagnose. Massive pulmonary embolism presenting with profound hypotension, however, is rare. Both phenomena carry with them significant mortality. Traditionally those patients suffering haemodynamic compromise from pulmonary embolism are treated with intravenous or catheter-directed thrombolysis. When this is contraindicated surgical embolectomy or mechanical techniques via a right heart catheter are alternative options. The former is well established but the latter is less commonly utilised in clinical practice. Our aim is to highlight the effectiveness and relative safety of percutaneous mechanical thrombectomy as a therapeutic tool in massive pulmonary embolism.

CASE PRESENTATION

A 70 year-old gentleman presented with a 4-month history of dry cough and general malaise. Clinical examination along with routine chest radiograph confirmed a left pleural effusion which was drained. Computed tomography of the chest, abdomen and pelvis revealed a left renal mass consistent with renal cell carcinoma plus multiple metastatic subpleural nodules. Following planned thoracoscopy and pleural biopsy the patient became acutely dyspnoeic and hypotensive. Relevant investigations including computed tomography pulmonary angiogram confirmed a large saddle embolus extending in to the lobar branches of both left and right pulmonary arteries. There were several relative contraindications to thrombolysis and so the patient proceeded to have percutaneous mechanical thrombectomy with excellent results. The patient made a full recovery from the acute episode and was discharged home on warfarin with a view to planned cyto-reductive nephrectomy.

CONCLUSION

We illustrate here that percutaneous mechanical thrombectomy can be a safe and effective method of treating massive pulmonary embolism when thrombolysis is relatively contraindicated. It may also be of use as an adjuvant therapy in those patients able to receive thrombolysis. In the future further evaluation involving a larger cohort of subjects is necessary to determine whether this treatment is superior to surgical embolectomy when thrombolysis cannot be performed.

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.

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.

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.

Rheolytic percutaneous thrombectomy for acute pulmonary embolism in a pediatric patient

Acute massive pulmonary embolism can have significant hemodynamic effects in both adults and children. We describe the case of a 10-year-old boy who developed cardiogenic shock after suffering a massive pulmonary embolism. A significant thrombus burden was removed using a catheter-based strategy of rheolytic thrombectomy, leading to stabilization of the patient.

Percutaneous rheolytic thrombectomy for large pulmonary embolism: A promising treatment option

BACKGROUND

Pulmonary embolism (PE) is a common cardiovascular disease with significant mortality. Some patients with large PE are not eligible for current treatment options such as thrombolysis or surgical embolectomy. We report our experience of percutaneous rheolytic thrombectomy (PRT) using the AngioJet system combined with adjunctive local thrombolytic therapy and inferior vena cava (IVC) filter placement to treat massive or submassive PE in patients ineligible for current treatment options.

METHODS AND RESULTS

Of the 14 consecutive patients ineligible for thrombolysis or embolectomy treated with PRT, 10 patients had massive PE (6 patients were hypotensive and 4 patients had intractable hypoxemia) and 4 patients had submassive PE. Adjunctive local thrombolysis was performed in 5 patients. An IVC filter was placed in 11 patients. Angiographic success based on Miller score was achieved in 13 patients (92.9%). Procedure success was obtained in 12 patients (85.7%). Procedural mortality occurred in one patient who presented in cardiogenic shock (7.1%) and non-fatal hemoptysis occurred in 1 patient (7.1%). Total in-hospital mortality occurred in 3 patients (21.4%). On a mean follow-up of 9 months, all 11 survivors had noted significant improvement in symptoms without recurrence.

CONCLUSIONS

Percutaneous rheolytic thrombectomy using the AngioJet may be a treatment option for patients with massive or submassive PE who may not be eligible for thrombolytic therapy or surgical embolectomy.

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.

AngioJet rheolytic thrombectomy versus local intrapulmonary thrombolysis in massive pulmonary embolism: a retrospective data analysis

PURPOSE

To compare the efficacy of full-dose local intrapulmonary thrombolysis (LIT) versus AngioJet rheolytic thrombectomy (ART) in the treatment of massive pulmonary embolism.

METHODS

A retrospective review was conducted of 8 consecutive patients (5 women; mean age 66.0+/-5.9 years, range 56-74) who underwent LIT with high-dose intrapulmonary urokinase (4400 IU/kg over 10 minutes followed by a 2000-IU/kg/h infusion) and a subsequent 6 consecutive patients (4 men; mean age of 59.2+/-17.0 years, range 26-69) who underwent ART plus adjunctive low-dose urokinase infusions (100,000 IU) until hemodynamic recovery was achieved. Pre and postprocedural Miller scores were calculated, and relative Miller score improvement, total urokinase doses, and duration of therapy were compared.

RESULTS

Hemodynamic stability was restored in all 8 LIT patients and in 5 (83%) of the 6 ART patients; 1 (16.7%) patient died during the ART procedure due to recurrent MPE. In the LIT group, the mean Miller score prior to intervention was 17.38+/-2.67, which was reduced to 6.13+/-1.46 after the intervention (p<0.0001) compared to scores of 18.83+/-2.86 and 6.83+/-2.79, respectively, in the ART group (p<0.0001). The mean urokinase dose was 2.07+/-0.44 million IU in the LIT group versus 0.70+/-0.36 million IU in the ART group (p<0.0001). The mean duration of therapy was 11.45+/-2.94 hours in the LIT group versus 3.37+/-1.41 hours in the ART group (p<0.0001). No significant difference in relative Miller score improvement was observed.

CONCLUSION

By accelerating the fragmentation of thrombus, ART plus adjunctive low-dose urokinase seems to be more rapidly effective compared to LIT. ART achieves both rapid cardiovascular relief and reduces the dose of thrombolytic agent necessary in patients with massive pulmonary embolism.

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.

Submassive pulmonary embolism and paradoxical embolic stroke treated with percutaneous rheolytic thrombectomy and closure of the patent foramen ovale

The presence of patent foramen ovale (PFO) in patients with large pulmonary emboli (PE) is associated with an increased risk of stroke and mortality. Many patients are ineligible to receive thrombolytic therapy. We present a patient with bilateral PE and cryptogenic stroke who was treated effectively with rheolytic thrombectomy with AngioJet, PFO closure with CardioSeal device, and placement of an inferior vena cava filter.

Antithrombotic therapy for venous thromboembolic disease: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy

This chapter about antithrombotic therapy for venous thromboembolic disease is part of the seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following: for patients with objectively confirmed deep vein thrombosis (DVT), we recommend short-term treatment with subcutaneous (SC) low molecular weight heparin (LMWH) or, alternatively, IV unfractionated heparin (UFH) [both Grade 1A]. For patients with a high clinical suspicion of DVT, we recommend treatment with anticoagulants while awaiting the outcome of diagnostic tests (Grade 1C+). In acute DVT, we recommend initial treatment with LMWH or UFH for at least 5 days (Grade 1C), initiation of vitamin K antagonist (VKA) together with LMWH or UFH on the first treatment day, and discontinuation of heparin when the international normalized ratio (INR) is stable and > 2.0 (Grade 1A). For the duration and intensity of treatment for acute DVT of the leg, the recommendations include the following: for patients with a first episode of DVT secondary to a transient (reversible) risk factor, we recommend long-term treatment with a VKA for 3 months over treatment for shorter periods (Grade 1A). For patients with a first episode of idiopathic DVT, we recommend treatment with a VKA for at least 6 to 12 months (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 against high-intensity VKA therapy (INR range, 3.1 to 4.0) [Grade 1A] and against low-intensity therapy (INR range, 1.5 to 1.9) compared to INR range of 2.0 to 3.0 (Grade 1A). For the prevention of the postthrombotic syndrome, we recommend the use of an elastic compression stocking (Grade 1A). For patients with objectively confirmed nonmassive PE, we recommend acute treatment with SC LMWH or, alternatively, IV UFH (both Grade 1A). For most patients with pulmonary embolism (PE), we recommend clinicians not use systemic thrombolytic therapy (Grade 1A). For the duration and intensity of treatment for PE, the recommendations are similar to those for DVT.

Use of Rheolytic Thrombectomy in Treatment of Acute Massive Pulmonary Embolism

PURPOSE

The 6-F Xpeedior (AngioJet; Possis Medical, Minneapolis, MN) rheolytic thrombectomy catheter (RTC) uses high velocity saline jets for thrombus aspiration, maceration, and evacuation, through the Bernoulli principle. The purpose of this study was to evaluate the efficacy of thrombus removal using the RTC in patients with acute massive pulmonary embolism (PE).

MATERIALS AND METHODS

Seventeen patients (mean age, 51.7 + 16.6 years; range, 30-86 years; 9 men, 8 women) with massive PE initially diagnosed by computed tomography (CT) or VQ scan and confirmed by pulmonary angiography were treated with the RTC. All patients had acute onset of PE symptoms and all presented with hemodynamic compromise and dyspnea. Ten of 17 patients had enough residual thrombus to warrant adjuvant catheter directed thrombolytic infusion with reteplase. Six patients had contraindications to thrombolytic therapy. One patient presented with renal cell carcinoma and tumor embolus as suspected cause of PE. Angiographic and clinical outcomes during the hospital stay were evaluated.

RESULTS

The RTC was successfully delivered and operated via a 0.035-inch guide wire in all attempted cases. Treatment resulted in immediate angiographic improvement and initial relief of PE symptoms (improvement in dyspnea and oxygen saturation) in 16 of 17 patients. One patient developed heart block during the procedure, and further treatment with the RTC was discontinued. Bradycardia occurred in one patient (managed with lidocaine). After thrombectomy, 10 patients received adjunctive reteplase thrombolysis for treatment of residual thrombus, and 12 received inferior vena cava (IVC) filters. In the patient with renal cell carcinoma, histopathologic analysis of the evacuated material confirmed tumor origin of the embolism. There were two deaths, both within 24 hours of treatment and secondary to PE. One death occurred in a patient who had only minimal thrombus removal after treatment with the RTC and no thrombolysis. The remaining 15 patients showed continued improvement in PE symptoms and were eventually discharged from the hospital with mean length of stay 10.3 + 6.5 days (range, 5-30 days).

CONCLUSIONS

Rheolytic thrombectomy can be performed effectively in patients with massive PE. However, a large portion of the patients in this study underwent adjuvant overnight thrombolytic infusion. Further evaluation in a larger cohort of patients is warranted to assess whether this treatment may offer an alternative or complement to thrombolysis or surgical thrombectomy.

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.

Suspected pulmonary artery disruption after transvenous pulmonary embolectomy using a hydrodynamic thrombectomy device: clinical case and experimental study on porcine lung explants

PURPOSE

To use porcine lung explants for reconstructing possible situations in which a vessel wall disruption might have occurred in a patient suffering fatal hemoptysis after pulmonary embolectomy with a hydrodynamic thrombectomy device.

METHODS

A 76-year-old woman with massive pulmonary embolism underwent transvenous pulmonary embolectomy using a 6-F AngioJet Xpeedior catheter according to manufacturer's instructions. While activating the device in the middle lobe artery (approximately 8 mm diameter), massive and ultimately fatal arterial bleeding occurred through the tracheal tube. Because no autopsy was authorized, an experimental study was designed to examine possible causes for the vessel disruption. Five fresh porcine heart-lung preparations were examined inside a dedicated chest phantom. Access to the pulmonary vessels was provided through catheters inside the right and left ventricular outlets. A low-flow circulation was maintained with an external pump. The 6-F AngioJet thrombectomy device was activated at 42 sites inside vessels from 2 to 10 mm in diameter; in one lung, 8 activations were made after deliberately withdrawing the guidewire.

RESULTS

Vessels >6 mm in diameter remained intact. Vessel wall disruption occurred in 4 of 7 vessels between 4 and 6 mm in diameter and in 13 of 14 segmental arteries <4 mm in diameter (regardless of whether or not a guidewire was used). The signs of vessel wall disruption included extravasation of contrast material, arteriovenous fistula, and laceration of distal airspaces with contrast inside the bronchus.

CONCLUSIONS

The application of this system has to be considered potentially dangerous when activated inside vessels with diameters <6 mm. The use of this device appears to be safe only inside main branches of the lung vessels at this time. Additional experiments will be required to substantiate these initial results.

Rheolytic Thrombectomy of Acute Stent Thrombosis of Cervical Vertebral Artery

A new Xpeedior rheolytic thrombectomy catheter has been successfully used to extract thrombus from an acutely thrombosed vertebral artery stent without apparent distal embolism. The ease of use and the speed of thrombectomy suggest that this system may be useful for the treatment of acute ischemic stroke.

Massive pulmonary embolism: a remarkable case and review of treatment

Although the clinical syndrome following pulmonary embolism (PE) may be subtle, in the case of massive PE the severity of the clinical presentation typically makes the picture more obvious. If more than two lobar pulmonary arteries become obstructed, the hemodynamic and respiratory consequences are severe, and may be life threatening. We present an unusual case where a patient experienced transient hemodynamic collapse during valsalva, and a massive saddle pulmonary embolus was discovered incidentally. Current treatment options for massive PE are then discussed.

In vitro effectiveness of mechanical thrombectomy devices for large vessel diameter and low-pressure fluid dynamic applications

PURPOSE

To determine in vitro the efficacy of clot removal of the AngioJet (AJ; new 6-F generation), Hydrolyser (HL; 6-F), and Oasis (OS; 6-F) hydrodynamic thrombectomy devices and the Amplatz Thrombectomy Device fragmentation catheter (ATD; 8-F and new-generation 7-F) in large-diameter vessels and low-pressure fluid dynamic applications (ie, pulmonary embolism).

MATERIALS AND METHODS

Thrombectomy of clots (N = 60; n = 12 for each tested device) created from 5-day-old porcine blood (16 g) was performed with the AJ (with coaxial 0.035-inch guide wire), HL, OS, and ATD in a bench-top model simulating low-pressure fluid dynamics (pulsed flow, 1,250 L/min). Tubes made of silicone (20-mm inner diameter) containing thrombus simulated a large-diameter vessel. The effluent was passed through a three-step filter system (10-1,000 micro m; pressure drop, 15 mm Hg).

RESULTS

Mean thrombectomy time ranged from 83 seconds (7-F ATD) to 185 seconds (OS; P <.0001 compared to all). Remaining thrombus ranged from 5.4 g/32.7% (AJ) to 11.1 g/68.1% (HL; P <.001 compared to all). The AJ's fluid balance was 0.92, whereas the mean ratio of applied saline solution to aspirated fluid for the other devices were significantly different than isovolumetric conditions (HL, 0.64; OS, 0.59; P <.0001 compared to AJ). The AJ (0.36%), HL (0.43%), and OS (0.38%) caused the least overall emboli larger than 10 micro m; the ATD (7-F, 0.82%; 8-F, 0.74%) caused the most (P <.001 for both).

CONCLUSIONS

The tested mechanical thrombectomy devices showed performance differences in thrombectomy time, efficacy of thrombus removal, and peripheral embolization rates. Based on low embolization rates for all devices tested, the experimental data indicate that the 7-F ATD and the 0.035-inch guide-wire-compatible AJ showed feasibility advantages for thrombectomy in large vessel diameter and low-pressure fluid dynamic applications.

Recent advances in pulmonary embolism diagnosis and management

Pulmonary embolism remains a major problem in clinical practice. Pulmonary angiography remains the most accurate diagnostic procedure. Standard therapy includes heparin then warfarin, and now low molecular weight heparin. The role of prophylactic measures cannot be over emphasized.

Diagnosis and treatment of venous thromboembolism

The diagnosis of deep vein thrombosis (DVT) and pulmonary embolism (PE) has been improved and simplified over the past decade thanks to advances in noninvasive and readily accessible technology. With high degrees of sensitivity and specificity, venous ultrasonography is favored as the initial investigation for DVT. To diagnose PE, most clinicians rely on diagnostic algorithms that combine clinical assessment, noninvasive lung studies, and, if necessary, venous ultrasonography of the legs and D-dimer testing. Substantial progress has also occurred in the treatment of acute venous thromboembolism with the introduction of low-molecular-weight heparins. This class of antithrombotic agents has changed initial therapy from an inpatient, intravenous regimen that required laborious monitoring to an outpatient practice using weight-adjusted doses of once-daily subcutaneous injections. In addition, several new anticoagulants with theoretical advantages over existing agents have entered phase III studies. Aspects of thrombosis treatment that remain controversial include vena caval interruption and the indications for thrombolysis and surgical thromboembolectomy.

Acute renal artery thrombosis treated by percutaneous rheolytic thrombectomy

Renal artery thrombosis or embolus is a rare condition that may lead to hypertension and renal failure. Treatment options in the past have had limited success. We present a case which demonstrates the use of percutaneous rheolytic therapy with the Angiojet atherectomy catheter to treat this condition in the acute setting.

Engineering design of optimal strategies for blood clot dissolution

Blood clots form under hemodynamic conditions and can obstruct flow during angina, acute myocardial infarction, stroke, deep vein thrombosis, pulmonary embolism, peripheral thrombosis, or dialysis access graft thrombosis. Therapies to remove these clots through enzymatic and/or mechanical approaches require consideration of the biochemistry and structure of blood clots in conjunction with local transport phenomena. Because blood clots are porous objects exposed to local hemodynamic forces, pressure-driven interstitial permeation often controls drug penetration and the overall lysis rate of an occlusive thrombus. Reaction engineering and transport phenomena provide a framework to relate dosage of a given agent to potential outcomes. The design and testing of thrombolytic agents and the design of therapies must account for (a) the binding, catalytic, and systemic clearance properties of the therapeutic enzyme; (b) the dose and delivery regimen; (c) the biochemical and structural aspects of the thrombotic occlusion; (d) the prevailing hemodynamics and anatomical location of the thrombus; and (e) therapeutic constraints and risks of side effects. These principles also impact the design and analysis of local delivery devices.

Emergency department management of pulmonary embolism

There are several points that bear repetition. First, consider the diagnosis of PE in all patients presenting with chest pain, dyspnea, syncope, oxygen desaturation, or unexplained hypotension. Evaluate these patients in a rational manner. At any individual hospital, develop algorithms with consultants so that when one is faced with a patient with a PE, the flow of both diagnostics and therapeutics flows smoothly and rapidly. Consider the concept of risk stratification, and remember that not all patients with PE are created equal. In particular, be on the same page with all consultants regarding the use of right heart echocardiography, both for its potential diagnostic capabilities and for its ability to identify patients who could be at greater risk for bad outcomes.

Mechanical thrombectomy of major and massive pulmonary embolism with use of the Amplatz thrombectomy device

RATIONALE AND OBJECTIVES

To evaluate the feasibility of mechanical thrombectomy with the Amplatz thrombectomy device (ATD) in restoring patency of acutely thrombosed pulmonary arteries resulting from pulmonary embolism for the improvement of patient outcome.

METHODS

Mechanical thrombectomy with the ATD (8F) was performed in nine consecutive patients with angiographically documented thrombus in the left or right pulmonary artery resulting from deep vein thrombosis (n = 4) or unknown cause (n = 5).

RESULTS

The Miller index decreased from 18 to 11. In all patients, the majority of the thrombus in the pulmonary artery was cleared after a mean activation time of the ATD of 367 seconds. Thrombectomy was performed with the ATD alone (n = 4) or with additional long-term fibrinolysis therapy (n = 5) with infusion of recombinant tissue-type plasminogen activator. Pulmonary arterial pressure decreased from a mean of 57 mm Hg before mechanical thrombectomy to 55 mm Hg directly after the procedure and to 39 mm Hg after termination of the recombinant tissue-type plasminogen activator infusion.

CONCLUSIONS

Mechanical thrombectomy with the ATD in patients with minor and major pulmonary embolism is technically feasible and safe. It is a potential alternative to drug-mediated thrombolysis and surgery. However, the incremental benefit of the ATD over conventional treatments could be shown only in a randomized controlled study.