Safety and Efficacy of Acute Pulmonary Embolism Treated via Large-Bore Aspiration Mechanical Thrombectomy Using the Inari FlowTriever Device

Risks and Benefits of Device-Assisted Treatment of Pulmonary Embolism

Pulmonary embolism (PE) is a common disease associated with significant morbidity and mortality. Despite the familiarity with this disease, the best treatment remains undefined. Traditionally, treatment of PE has involved a choice of anticoagulation, thrombolysis, or surgery. However, the debate over pharmacologic versus mechanical treatment of acute PE reared up again with the advent of user-friendly mechanical and aspiration thrombectomy technologies. This is especially true for submassive PE, which is an area for potential growth both for understanding the pathophysiology of the disease process and management. Multiple devices are available for treatment of PE. Understanding the risks and benefits of each device is paramount in the complex management of PE.

Catheter Interventions for Pulmonary Embolism: Mechanical Thrombectomy Versus Thrombolytics

Pulmonary embolism is a debilitating and potentially life-threatening disease characterized by high mortality and long-term adverse outcomes. Traditional treatment options are fraught with serious bleeding risks and incomplete thrombus removal, necessitating the development of innovative treatment strategies. While new interventional approaches offer promising potential for improved outcomes with fewer serious complications, their rapid development and need for more comparative clinical evidence makes it challenging for physicians to select the optimal treatment for each patient among the many options. This review summarizes the current published clinical data for both traditional treatments and more recent interventional approaches indicated for pulmonary embolism. While published studies thus far suggest that these newer interventional devices offer safe and effective options, more data is needed to understand their impact relative to the standard of care. The studies in progress that are anticipated to provide needed evidence are reviewed here since they will be critical for helping physicians make informed treatment choices and potentially driving necessary guideline changes.

Electrocardiographic Changes after Endovascular Mechanical Thrombectomy in a Patient with Pulmonary Embolism-A Case Report and Literature Review

Background: Pulmonary embolism (PE) is a common disease with an annual incidence of about 1/1000 persons. About every sixth patient dies within the first 30 days after diagnosis. The electrocardiogram (ECG) is one of the first diagnostic tests performed, and is able to confirm the suspicion of PE with typical electrocardiographic signs. Some ECG signs and their regression are also prognostically relevant. Endovascular mechanical thrombectomy is one option for PE treatment, and aims to relieve right heart strain immediately. The first studies on endovascular mechanical thrombectomy using a dedicated device (FlowTriever System, Inari Medical, Irvine, CA, USA) yielded promising results. Methods: In the following, we report the case of a 66-year-old male patient who presented with New York Heart Association III dyspnea in our emergency department. Among typical clinical and laboratory results, he displayed very impressive electrocardiographic and radiological findings at the time of PE diagnosis. Results: After endovascular mechanical thrombectomy, the patient's complaints and pulmonary hemodynamics improved remarkably. In contrast, the ECG worsened paradoxically 18 h after intervention. Nevertheless, control echocardiography 4 days after the intervention no longer showed any signs of right heart strain, and dyspnea had disappeared completely. At a 4-month follow-up visit, the patient presented as completely symptom-free with a high quality of life. His ECG and echocardiography were normal and excluded recurrent right heart strain. Conclusions: Overall, the patient benefitted remarkably from endovascular mechanical thrombectomy, resulting in an almost complete resolution of electrocardiographic PE signs at the 4-month follow-up after exhibiting multiple typical electrocardiographic PE signs at time of diagnosis and initial electrocardiographic worsening 18 h post successful intervention.

Aspiration of thrombus for intermediate-risk subacute pulmonary embolism

Pulmonary embolism is the most common cardiovascular disease after myocardial infarction and stroke. Konstantinides (Eur Heart J 41(4):543-603, 2020) Current guidelines categorize patients with PE as being at low, intermediate, and high risk of early death, with the intermediate-risk group experiencing the greatest uncertainty regarding treatment recommendations. Rapid reduction of the thrombus load by thrombolysis significantly reduces symptoms and decreases mortality, but is accompanied by a high risk of bleeding. Meyer (N Engl J Med 370(15):1402-11, 2014) Mechanical thrombectomy (CDTE) have been proven safe and efficient, yet current ESC guidelines suggest the utilization of catheter interventions only for hypotensive patients with high bleeding risk, failed systemic thrombolysis, and cardiogenic shock or if a patient does not respond to conservative therapy Konstantinides (Eur Heart J 41(4):543-603, 2020). Here, we report a case of an intermediate-risk patient with pulmonary embolism who underwent thrombus aspiration and showed significant improvement in symptoms after treatment.

A meta-analysis of outcomes of aspiration thrombectomy for high and intermediate-risk pulmonary embolism

BACKGROUND

Aspiration thrombectomy has gained popularity in patients with massive and sub-massive pulmonary embolism (PE) and having contraindications to thrombolysis.

METHODS

A meta-analysis was conducted including studies on aspiration thrombectomy in patients with high-risk and intermediate-risk PE. The pooled odds ratio for efficacy parameters, including change in heart rate, blood pressure and right ventricle/left ventricle (RV/LV) ratio, and safety parameters including major bleeding and stroke, was calculated using a random effects model.

RESULTS

The meta-analysis of 24 selected studies revealed that intermediate and high-risk pulmonary embolism (PE) patients demonstrated significant improvements: modified Miller score odds ratio of 10.60, mean pulmonary artery pressure reduction by 0.04 mm Hg, and an overall all-cause mortality odds ratio of 0.10. Considerable heterogeneity was observed in various outcomes.

CONCLUSION

Aspiration thrombectomy has success rates in both high-risk and intermediate-risk PE, however, procedural risks, including bleeding, must be anticipated.

Syringe-assisted test-aspiration with mechanical aspiration thrombectomy results in good safety and short-term outcomes in the treatment of patients with deep venous thrombosis

OBJECTIVE

To evaluate the short-term outcomes and safety of syringe-assisted test-aspiration with mechanical aspiration thrombectomy in the treatment of deep venous thrombosis.

METHODS

This was a single-center, retrospective study of hospitalized patients with iliofemoral and/or inferior vena caval deep venous thrombosis, excluding those with pulmonary embolism. We collected the following patient data from the electronic medical records: age, sex, provoked/unprovoked deep venous thrombosis, symptom duration, thrombosed segments, and the presence of a tumor, thrombophilia, diabetes, and/or iliac vein compression syndrome. Venography and computed tomographic venography were performed in all patients before the procedure. All patients underwent syringe-assisted test-aspiration with mechanical aspiration thrombectomy under local anesthesia and sedation, and all received low-molecular-weight heparin peri-operatively. All patients underwent implantation of an inferior vena caval filter. Rivaroxaban was administered post-procedure, instead of heparin, for 3-6 months, with lower extremity compression.

RESULTS

Overall, 29 patients with deep venous thrombosis underwent syringe-assisted test-aspiration with mechanical aspiration thrombectomy from January 2022 to October 2022 in our institution. Technical success (>70% thrombus resolution) was achieved in all patients, and using a single procedure in 25/29 patients (86%). Concomitant stenting was performed in 18/29 (62%) of the patients, and 21/29 (69%) underwent angioplasty. The median (interquartile range) procedure time was 110 min (100-122), the median intra-operative bleeding volume was 150 mL (120-180), and the median decrease in the hemoglobin concentration from pre- to post-operative was 7 g/L (4-14). The median follow-up duration was 7 months (5-9). All patients obtained symptomatic relief, and 27/29 achieved near-remission or full remission (combined total). No patients experienced peri-operative bleeding complications, or symptom recurrence or post-thrombectomy syndrome during follow-up.

CONCLUSION

The short-term outcomes following syringe-assisted test-aspiration with mechanical aspiration thrombectomy in the treatment of deep venous thrombosis were excellent, and the procedure was safe.

Anesthetic management in patients having catheter-based thrombectomy for acute pulmonary embolism: A narrative review

Pulmonary embolism is the third leading cause of cardiovascular death. Novel percutaneous catheter-based thrombectomy techniques are rapidly becoming popular in high-risk pulmonary embolism - especially in the presence of contraindications to thrombolysis. The interventional nature of these procedures and the risk of sudden cardiorespiratory compromise requires the presence of an anesthesiologist. Facilitating catheter-based thrombectomy can be challenging since qualifying patients are often critically ill. The purpose of this narrative review is to provide guidance to anesthesiologists for the assessment and management of patients having catheter-based thrombectomy for acute pulmonary embolism. First, available techniques for catheter-based thrombectomy are reviewed. Then, we discuss definitions and application of common risk stratification tools for pulmonary embolism, and how to assess patients prior to the procedure. An adjudication of risks and benefits of anesthetic strategies for catheter-based thrombectomy follows. Specifically, we give guidance and rationale for use monitored anesthesia care and general anesthesia for these procedures. For both, we review strategies for assessing and mitigating hemodynamic perturbations and right ventricular dysfunction, ranging from basic monitoring to advanced inodilator therapy. Finally, considerations for management of right ventricular failure with mechanical circulatory support are discussed.

High-Risk Pulmonary Embolism: Management for the Intensivist

High-risk pulmonary embolism (PE) also known as massive PE carries a high rate of morbidity and mortality. The incidence of high-risk PE continues to increase, yet the outcomes of high-risk PE continue to remain poor. Patients with high-risk PE are often critically ill, with complex underlying physiology, and treatment for the high-risk PE patient almost always requires care and management from an intensivist. Treatment options for high-risk PE continue to evolve rapidly with multiple options for definitive reperfusion therapy and supportive care. A thorough understanding of the physiology, risk stratification, treatment, and support options for the high-risk PE patient is necessary for all intensivists in order to improve outcomes. This article aims to provide a review from an intensivist's perspective highlighting the physiological consequences, risk stratification, and treatment options for these patients as well as providing a proposed algorithm to the risk stratification and acute management of high-risk PE.

Randomized controlled trial of mechanical thrombectomy vs catheter-directed thrombolysis for acute hemodynamically stable pulmonary embolism: Rationale and design of the PEERLESS study

BACKGROUND

The identification of hemodynamically stable pulmonary embolism (PE) patients who may benefit from advanced treatment beyond anticoagulation is unclear. However, when intervention is deemed necessary by the PE patient's care team, data to select the most advantageous interventional treatment option are lacking. Limiting factors include major bleeding risks with systemic and locally delivered thrombolytics and the overall lack of randomized controlled trial (RCT) data for interventional treatment strategies. Considering the expansion of the pulmonary embolism response team (PERT) model, corresponding rise in interventional treatment, and number of thrombolytic and nonthrombolytic catheter-directed devices coming to market, robust evidence is needed to identify the safest and most effective interventional option for patients.

METHODS

The PEERLESS study (ClinicalTrials.gov identifier: NCT05111613) is a currently enrolling multinational RCT comparing large-bore mechanical thrombectomy (MT) with the FlowTriever System (Inari Medical, Irvine, CA) vs catheter-directed thrombolysis (CDT). A total of 550 hemodynamically stable PE patients with right ventricular (RV) dysfunction and additional clinical risk factors will undergo 1:1 randomization. Up to 150 additional patients with absolute thrombolytic contraindications may be enrolled into a nonrandomized MT cohort for separate analysis. The primary end point will be assessed at hospital discharge or 7 days post procedure, whichever is sooner, and is a composite of the following clinical outcomes constructed as a hierarchal win ratio: (1) all-cause mortality, (2) intracranial hemorrhage, (3) major bleeding, (4) clinical deterioration and/or escalation to bailout, and (5) intensive care unit admission and length of stay. The first 4 components of the win ratio will be adjudicated by a Clinical Events Committee, and all components will be assessed individually as secondary end points. Other key secondary end points include all-cause mortality and readmission within 30 days of procedure and device- and drug-related serious adverse events through the 30-day visit.

IMPLICATIONS

PEERLESS is the first RCT to compare 2 different interventional treatment strategies for hemodynamically stable PE and results will inform strategy selection after the physician or PERT determines advanced therapy is warranted.

FlowTriever System for Pulmonary Embolism: A Review of Clinical Evidence

Pulmonary embolism (PE) is a significant cause of cardiovascular mortality, and its incidence has been increasing due to the growing aging population. Systemic or catheter-directed thrombolytic treatment for PE has an increased risk of bleeding that may offset the benefit in some patients. Mechanical thrombectomy devices such as the FlowTriever System are designed to resolve vascular occlusion and correct ventilation-perfusion mismatch without the need for thrombolytic drugs. This review covers the FlowTriever system, clinical data from the FlowTriever Pulmonary Embolectomy Clinical Study, FlowTriever for Acute Massive Pulmonary Embolism, and FlowTriever All-comer Registry for Patient Safety and Hemodynamics trials, and real-world experiences, demonstrating its safety and effectiveness in treating intermediate-risk and high-risk PE. Additionally, we explore off-label uses of the FlowTriever System for various large vessel thromboses.

Interventional therapies for pulmonary embolism

Pulmonary embolism (PE) is the leading cause of in-hospital death and the third most frequent cause of cardiovascular death. The clinical presentation of PE is variable, and choosing the appropriate treatment for individual patients can be challenging. Traditionally, treatment of PE has involved a choice of anticoagulation, thrombolysis or surgery; however, a range of percutaneous interventional technologies have been developed that are under investigation in patients with intermediate-high-risk or high-risk PE. These interventional technologies include catheter-directed thrombolysis (with or without ultrasound assistance), aspiration thrombectomy and combinations of the aforementioned principles. These interventional treatment options might lead to a more rapid improvement in right ventricular function and pulmonary and/or systemic haemodynamics in particular patients. However, evidence from randomized controlled trials on the safety and efficacy of these interventions compared with conservative therapies is lacking. In this Review, we discuss the underlying pathophysiology of PE, provide assistance with decision-making on patient selection and critically appraise the available clinical evidence on interventional, catheter-based approaches for PE treatment. Finally, we discuss future perspectives and unmet needs.

Cardiovascular collapse during mechanical thrombectomy for acute pulmonary embolism and the role of extracorporeal membrane oxygenation in patient rescue

BACKGROUND

Driven by the ability to avoid thrombolytics and provide a one stop procedure with immediate hemodynamic improvement, there has been a dramatic increase in the use of mechanical thrombectomy (MT) devices for the treatment of intermediate-to-high risk pulmonary embolism (PE). This study investigated the incidence and outcomes of cardiovascular collapse during MT procedures and demonstrates the role of extracorporeal membrane oxygenation (ECMO) in salvaging patients.

METHODS

This single-center retrospective review included patients with PE undergoing MT with the FlowTriever device between 2017 and 2022. Patients presenting periprocedural cardiac arrest were identified and their perioperative characteristics and postoperative outcomes were evaluated.

RESULTS

A total of 151 patients with a mean age of 64 ± 14 years who presented with intermediate-to-high risk PE received LBAT procedures during the study period. The simplified PE severity score was ≥1 in 83% of cases and the average RV/LV ratio was 1.6 ± 0.5, with and elevated troponin in 84%. Technical success was achieved in 98.7% and a significant decrease in pulmonary artery systolic pressure (PASP) was observed (37 mm Hg vs 56 mm Hg; P < .0001). Intraoperative cardiac arrest occurred in nine patients (6%). These patients were more likely to present PASP of ≥70 mm Hg (84% vs 14%; P < .001), were more hypotensive upon admission (systolic of 94 ± 14 mm Hg vs 119 ± 23 mm Hg; P = .004), presented lower oxygen saturation levels (87 ± 6% vs 92 ± 6%; P = .023) and were more likely to present with a history of recent surgery (67% vs 18%; P = .004). Four patients were rescued successfully with ECMO and their residual PE was subsequently removed before discharge by surgical embolectomy in two of the four cases and repeat MT in the other two. All five patients (3%) who did not receive ECMO support expired intraoperatively. The overall 30-day mortality was 8% with no death occurring in patients who were salvaged with ECMO.

CONCLUSIONS

Large-bore aspiration thrombectomy for acute PE is associated with favorable technical outcomes, but the concern for acute cardiac decompensation is non-negligible in patients presenting with high-risk features and a PASP of ≥70 mm Hg. ECMO can help to salvage some of these patients and should be considered in the treatment algorithms of patients deemed at high risk.

Case Series of Patients With Intermediate-High Risk Pulmonary Embolism in the Setting of Trauma Undergoing Mechanical Thrombectomy

In patients with pulmonary embolism (PE) in the setting of trauma, administration of fibrinolytic therapy is contraindicated due to high risk of hemorrhage. Several studies have demonstrated the safety and efficacy of mechanical thrombectomy among all-comers with PE as an alternative to catheter-directed thrombolytics. However, the risks and benefits of mechanical thrombectomy treatment for pulmonary embolism in a trauma population are not well established. A retrospective analysis was performed in all patients who presented to Level 1 Trauma Center with acute trauma who were found to have a pulmonary embolism (PE) treated with mechanical thrombectomy. From May 2019 to December 2020, six patients were identified. Average age was 54 years, and four patients were male. Four patients had a saddle PE on computed tomography. All patients had an intermediate-high risk PE with troponin I elevation >0.04 ng/mL (average 0.42 ng/mL). Pulmonary Embolism Severity Index (PESI) score in all six patients was class III or IV. In all patients, the mechanical thrombectomy was performed with mean-PA pressure changing from average 40.33 to 31.5 mmHg. Average Intensive Care Unit (ICU) length of stay post-procedure was five days with two patients not requiring ICU stay. No patient had post-operative bleeding during their index stay. Average hemoglobin drop after mechanical thrombectomy was 1.33 g/dL. One patient died <30 days post-procedure due to septic shock and another >90 days later (5 months) from cardiac arrest from recurrent PE. The other four patients were still living >90 days post-procedure. No immediate or delayed postoperative complications were identified. Mechanical thrombectomy appears to be a safe and effective treatment for patients with recent trauma who have an intermediate-high risk pulmonary embolism.

Large-Bore Mechanical Thrombectomy of Acute Pulmonary Embolism at a Community-Based Hospital: A Case Series

Acute pulmonary embolism (PE) is a common, and sometimes fatal, diagnosis that results in over 11,000 deaths in hospitalized patients in the USA annually. In patients with high-risk or high-intermediate-risk PE and especially in whom thrombolytic therapy is contraindicated, mechanical thrombectomy can be an effective treatment option. This case series outlines three patients with PE who were successfully treated with large bore aspiration thrombectomy by Interventional Radiology at a community-based military treatment facility (MTF). Two patients had presented to the emergency department with acute PE and a third of patients with acute PE were transferred from an outside hospital specifically for mechanical thrombectomy due to a complication from systemic anticoagulation. The patients were categorized as good candidates for immediate large-bore aspiration thrombectomy, a recently added capability at the MTF. The patients showed immediate improvement post-procedure and required only one night admission for observation to the intensive care unit. Implementation of this new capability for patients with acute high-risk or high-intermediate-risk PE or with contraindications to thrombolysis provides an alternative treatment with immediate, life-saving capability.

Catheter-Directed Thrombolysis or Catheter-Based Thrombectomy in Acute Pulmonary Embolism: Horses for Courses

Venous thromboembolism is a common disorder encompassing both pulmonary embolism (PE) and deep vein thrombosis (DVT). In the United States, up to 2 million people are diagnosed with DVT and 600,000 with PE annually. The purpose of this review is to discuss the indications and evidence for catheter-directed thrombolysis versus catheter-based thrombectomy.

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.

Circumstances of Hospitalization Impact Outcomes of Pulmonary Embolism

BACKGROUND

Clinical tools that stratify risk of acute pulmonary embolism (PE) are useful in guiding therapeutic decision making, although may neglect pragmatic and potentially impactful characteristics of hospitalization during care of venous thromboembolism (VTE).

METHODS

Using a retrospective cohort design, consecutive patients discharged after inpatient care for acute PE were retrospectively evaluated for features of hospitalization, including patient characteristics, treatment efficiency, and circumstances of hospitalization. A proportional hazards model incorporated non-traditional risk factors to assess their association with a primary composite endpoint of in-hospital bleeding or death after adjusting for conventional PE risk estimators, including the Pulmonary Artery Severity Index (PESI) and right ventricular/left ventricular (RV/LV) ratio.

RESULTS

From January 2016 to December 2018, 822 patients were discharged after treatment for acute PE, including high-risk (5.0%), intermediate-risk (64.2%), and low-risk (30.8%) PE. In-hospital death was 10-fold higher among those with high-risk PE compared to intermediate risk PE (36.6% vs 3.0%, p<0.001). Overall, 60.4% of hospitalizations were primarily attributed to presentation with VTE. High risk PE was observed more frequently as a secondary event during hospitalizations ostensibly unrelated to VTE (26.8%). After adjustment for PESI score and RV/LV ratio, hypoalbuminia, IVC filter, and non-VTE hospitalization had strong associations with the primary composite outcome.

CONCLUSIONS

Along with known markers of risk associated with PE, hypoalbuminia, IVC filter placement, and PE complicating hospitalization for circumstances not primarily related to VTE had strong associations with bleeding and death. These findings highlight the complex circumstances of acute PE care and need to refine practical risks.

Technical Feasibility of Suction Thrombectomy Using a Large-Bore Aspiration System in the Portomesenteric Venous System

PURPOSE

To assess technical feasibility and safety of portal vein thrombectomy with suction thrombectomy using a large-bore thrombectomy device for portomesenteric venous thrombosis (PMVT).

MATERIALS AND METHODS

After receiving approval from institutional review board, patients undergoing PMVT treatment using a large-bore aspiration thrombectomy device (Inari FlowTriever or ClotTriever) between July 2019 and June 2021 were identified at 2 medical centers. Charts were reviewed for demographic information, imaging findings, and procedural details. PMVT was categorized using the Yerdel grading system. The thrombectomy procedure was performed via transjugular access through the existing or a new transjugular intrahepatic portosystemic shunt (TIPS) or transsplenic or transhepatic approach. Technical success was defined as successful clot reduction and restoration of portal venous flow at the conclusion of the procedure. Patient outcomes based on clinical presentation, adverse events, and thrombectomy-associated adverse events were recorded.

RESULTS

Twenty patients, with a median age of 58 years (range, 23-72 years), underwent large-bore aspiration thrombectomy, which was technically successful in 19 of 20 (95%) patients. In 9 of 20 (45%) patients, 9 of 20 (45%) patients, and 2 of 20 (10%) patients, the 20-F, 16-F, and 24-F devices were used, respectively. Fourteen patients had a pre-existing TIPS, and 6 patients had a TIPS created. In 5 of 20 (25%) patients, overnight lysis was performed in conjunction with Inari thrombectomy. Thrombus resolution with restoration of flow was achieved in 19 of 20 (95%) cases. There were no thrombectomy-associated adverse events. The mean follow-up time was 70 days (±113) at which time primary patency of the portal venous system was present in 16 of 20 (80%) patients.

CONCLUSIONS

Large-bore aspiration portal vein thrombectomy is feasible for PMVT.

Acute outcomes for the full US cohort of the FLASH mechanical thrombectomy registry in pulmonary embolism

BACKGROUND

Evidence supporting interventional pulmonary embolism (PE) treatment is needed.

AIMS

We aimed to evaluate the acute safety and effectiveness of mechanical thrombectomy for intermediate- and high-risk PE in a large real-world population.

METHODS

FLASH is a multicentre, prospective registry enrolling up to 1,000 US and European PE patients treated with mechanical thrombectomy using the FlowTriever System. The primary safety endpoint is a major adverse event composite including device-related death and major bleeding at 48 hours, and intraprocedural adverse events. Acute mortality and 48-hour outcomes are reported. Multivariate regression analysed characteristics associated with pulmonary artery pressure and dyspnoea improvement.

RESULTS

Among 800 patients in the full US cohort, 76.7% had intermediate-high risk PE, 7.9% had high-risk PE, and 32.1% had thrombolytic contraindications. Major adverse events occurred in 1.8% of patients. All-cause mortality was 0.3% at 48-hour follow-up and 0.8% at 30-day follow-up, with no device-related deaths. Immediate haemodynamic improvements included a 7.6 mmHg mean drop in mean pulmonary artery pressure (-23.0%; p<0.0001) and a 0.3 L/min/m2 mean increase in cardiac index (18.9%; p<0.0001) in patients with depressed baseline values. Most patients (62.6%) had no overnight intensive care unit stay post-procedure. At 48 hours, the echocardiographic right ventricle/left ventricle ratio decreased from 1.23±0.36 to 0.98±0.31 (p<0.0001 for paired values) and patients with severe dyspnoea decreased from 66.5% to 15.6% (p<0.0001).  Conclusions: Mechanical thrombectomy with the FlowTriever System demonstrates a favourable safety profile, improvements in haemodynamics and functional outcomes, and low 30-day mortality for intermediate- and high-risk PE.

Percutaneous thrombectomy in patients with intermediate- and high-risk pulmonary embolism and contraindications to thrombolytics: a systematic review and meta-analysis

Catheter-directed interventions have slowly been gaining ground in the treatment of pulmonary embolism (PE), especially in patients with increased risk of bleeding. The goal of this study is to summarize the evidence for the efficacy and safety of percutaneous thrombectomy (PT) in patients with contraindications to systemic and local thrombolysis. We performed a systematic review and meta-analysis using MEDLINE, Cochrane, Scopus and the Web of Science databases for studies from inception to March 2022. We included patients with intermediate- and high-risk PE with contraindications to thrombolysis; patients who received systematic or local thrombolysis were excluded. Primary endpoint was in-hospital and 30-day mortality, with secondary outcomes based on hemodynamic and radiographic changes. Major bleeding events were assessed as a safety endpoint. Seventeen studies enrolled 455 patients, with a mean age of 58.6 years and encompassing 50.4% females. In-hospital and 30-day mortality rates were 4% (95% CI 3-6%) and 5% (95% CI 3-9%) for all-comers, respectively. We found a post-procedural reduction in systolic and mean pulmonary arterial pressures by 15.4 mmHg (95% CI 7-23.7) and 10.3 mmHg (95% CI 3.1-17.5) respectively. The RV/LV ratio and Miller Index were reduced by 0.42 (95% CI 0.38-46) and 7.8 (95% CI 5.2-10.5). Major bleeding events occurred in 4% (95% CI 3-6%). This is the first meta-analysis to report pooled outcomes on PT in intermediate- and high-risk PE patients without the use of systemic or local thrombolytics. The overall mortality rate is comparable to other contemporary treatments, and is an important modality particularly in those with contraindications for adjunctive thrombolytic therapy. Further studies are needed to understand the interplay of anticoagulation with PT and catheter-directed thrombolysis.

Outcomes of Catheter-Based Pulmonary Artery Embolectomy in Patients With Sub-Massive to Massive Pulmonary Embolism

Background Pulmonary embolism (PE) is the third leading cause of cardiovascular death after myocardial infarction and stroke. The ideal therapeutic approach for these patients remains undetermined. We report our single-center outcome data for using a catheter-based pulmonary artery thrombectomy using the FlowTriever (Inari Medical, Irvine, CA) device as management for patients with submassive PE. Methods We retrospectively collected data from a single center of patients who underwent thrombectomy using INARI FlowTriever device. The data on baseline characteristics, procedural and clinical outcomes was collected and analysed Results A total of 38 patients with PE treated endovascularly with the FlowTriever device were identified: 33 with submassive PE and five with massive PE. The mean age was 65.9 years (95% CI 61.9 - 69.8), and most patients were male (73.7%). All patients had right heart strain as the main indication for thrombectomy. Four patients (10.53%) required pressor support before the procedure. In 31 patients, pre- and post-thrombectomy average mean pulmonary artery pressure (mPAP) was improved significantly by 22% (p < 0.01). Two patients had significant adverse events at 48 hours (5.26%). One patient experienced procedure-related access site hematoma and life-threatening bleeding, while another developed intraprocedural-related massive hemoptysis and cardiopulmonary arrest. Overall post-procedural length of stay was 7.7 ± 5.6 days; 52.63% of patients (n = 20) required intensive care. Three patients (7.89%) required pressor support before the procedure, and 78.9% of patients (n = 30 of 38) survived hospital discharge. Thirty patients who survived were discharged with oral anticoagulation. There were no device-related complications. Conclusion Randomized trials of interventional devices for submassive PE are warranted to either support or alert the medical community of the safety and efficacy of their use for patients with submassive and massive PE. In time, pulmonary embolism response team (PERT) may generate outcome data that better inform treatment decisions.

Percutaneous Management of High-Risk Pulmonary Embolism

Acute pulmonary embolism (PE) leads to an abrupt increase in pulmonary vascular resistance and right ventricular afterload, and when significant enough, can result in hemodynamic instability. High-risk PE is a dire cardiovascular emergency and portends a poor prognosis. Traditional therapeutic options to rapidly reduce thrombus burden like systemic thrombolysis and surgical pulmonary endarterectomy have limitations, both with regards to appropriate candidates and efficacy, and have limited data demonstrating their benefit in high-risk PE. There are growing percutaneous treatment options for acute PE that include both localized thrombolysis and mechanical embolectomy. Data for such therapies with high-risk PE are currently limited. However, given the limitations, there is an opportunity to improve outcomes, with percutaneous treatments options offering new mechanisms for clot reduction with a possible improved safety profile compared with systemic thrombolysis. Additionally, mechanical circulatory support options allow for complementary treatment for patients with persistent instability, allowing for a bridge to more definitive treatment options. As more data develop, a shift toward a percutaneous approach with mechanical circulatory support may become a preferred option for the management of high-risk PE at tertiary care centers.

Percutaneous Large-Bore Pulmonary Thrombectomy with the FlowTriever Device: Initial Experience in Intermediate-High and High-Risk Patients

OBJECTIVES

This retrospective cohort study investigates outcomes of patients with intermediate-high and high-risk pulmonary embolism (PE) who were treated with transfemoral mechanical thrombectomy (MT) using the large-bore Inari FlowTriever aspiration catheter system.

MATERIAL AND METHODS

Twenty-seven patients (mean age 56.1 ± 15.3 years) treated with MT for PE between 04/2021 and 11/2021 were reviewed. Risk stratification was performed according to European Society of Cardiology (ESC) guidelines. Clinical and hemodynamic characteristics before and after the procedure were compared with the paired Student's t test, and duration of hospital stay was analyzed with the Kaplan-Meier estimator. Procedure-related adverse advents were assessed.

RESULTS

Of 27 patients treated, 18 were classified as high risk. Mean right-to-left ventricular ratio on baseline CT was 1.7 ± 0.6. After MT, a statistically significant reduction in mean pulmonary artery pressures from 35.9 ± 9.6 to 26.1 ± 9.0 mmHg (p = 0.002) and heart rates from 109.4 ± 22.5 to 82.8 ± 13.8 beats per minute (p < 0.001) was achieved. Two patients died of prolonged cardiogenic shock. Three patients died of post-interventional complications of which a paradoxical embolism can be considered related to MT. One patient needed short cardiopulmonary resuscitation during the procedure due to clot displacement. Patients with PE as primary driver of clinical instability had a median intensive care unit (ICU) stay of 2 days (0.5-3.5 days). Patients who developed PE as a complication of an underlying medical condition spent 11 days (9.5-12.5 days) in the ICU.

CONCLUSION

In this small study population of predominantly high-risk PE patients, large-bore MT without adjunctive thrombolysis was feasible with an acceptable procedure-related complication rate.

Mechanical aspiration thrombectomy for the treatment of pulmonary embolism: A systematic review and meta-analysis

INTRODUCTION

There are no randomized trials studying the outcomes of mechanical aspiration thrombectomy (MAT) for management of pulmonary embolism (PE).

METHODS

We performed a systematic review and meta-analysis of existing literature to evaluate the safety and efficacy of MAT in the setting of PE. Inclusion criteria were as follows: studies reporting more than five patients, study involved MAT, and reported clinical outcomes and pulmonary artery pressures. Studies were excluded if they failed to separate thrombectomy data from catheter-directed thrombolysis data. Databases searched include PubMed, EMBASE, Web of Science until April, 2021.

RESULTS

Fourteen case series were identified, consisting of 516 total patients (mean age 58.4 ± 13.6 years). Three studies had only high-risk PE, two studies had only intermediate-risk PE, and the remaining nine studies had a combination of both high-risk and intermediate-risk PE. Six studies used the Inari FlowTriever device, five studies used the Indigo Aspiration system, and the remaining three studies used the Rotarex or Aspirex suction thrombectomy system. Four total studies employed thrombolytics in a patient-specific manner, with seven receiving local lysis and 17 receiving systemic lysis, and 40 receiving both. A random-effects meta-analyses of proportions of in-hospital mortality, major bleeding, technical success, and clinical success were calculated, which yielded estimate pooled percentages [95% CI] of 3.6% [0.7%, 7.9%], 0.5% [0.0%, 1.8%], 97.1% [94.8%, 98.4%], and 90.7% [85.5%, 94.3%].

CONCLUSION

There is significant heterogeneity in clinical, physiologic, and angiographic data in the currently available data on MAT. RCTs with consistent parameters and outcomes measures are still needed.

A report of 2 cases of the use of the Inari FlowTriever System in the treatment of pulmonary embolism

The FlowTriever System (Inari Medical, Irvine, California) is the first FDA-approved mechanical thrombectomy device used for treatment of pulmonary embolism. This device enables nonsurgical removal of pulmonary blood clots without the use of thrombolytic medication and its associated risks. We report 2 cases of successful application of the Inari FlowTriever in treatment of pulmonary embolism and right atrial thrombus.

Percutaneous treatment options for acute pulmonary embolism: a clinical consensus statement by the ESC Working Group on Pulmonary Circulation and Right Ventricular Function and the European Association of Percutaneous Cardiovascular Interventions

There is a growing clinical and scientific interest in catheter-directed therapy (CDT) of acute pulmonary embolism (PE). Currently, CDT should be considered for patients with high-risk PE, in whom thrombolysis is contraindicated or has failed. Also, CDT is a treatment option for initially stable patients in whom anticoagulant treatment fails, i.e., those who experience haemodynamic deterioration despite adequately dosed anticoagulation. However, the definition of treatment failure (primary reperfusion therapy or anticoagulation alone) remains an important area of uncertainty. Moreover, several techniques for CDT are available without evidence supporting one over the other, and variation in practice with regard to periprocedural anticoagulation is considerable. The aim of this position paper is to describe the currently available CDT approaches in PE patients and to standardise patient selection, the timing and technique of the procedure itself as well as anticoagulation regimens during CDT. We discuss several clinical scenarios of the clinical evaluation of the "efficacy" of thrombolysis and anticoagulation, including treatment failure with haemodynamic deterioration and treatment failure based on a lack of improvement. This clinical consensus statement serves as a practical guide for CDT, complementary to the formal guidelines.

Contemporary Management of Acute Pulmonary Embolism: Evolution of Catheter-based Therapy

Acute pulmonary embolism (PE) affects more than 100 000 people in the United States annually and is the third leading cardiovascular cause of death. The standard management for PE is systemic anticoagulation therapy. However, a subset of patients experience hemodynamic decompensation, despite conservative measures. Traditionally, these patients have been treated with systemic administration of thrombolytic agents or open cardiac surgery, although attempts at endovascular treatment have a long history that dates back to the 1960s. The technology for catheter-based therapy for acute PE is rapidly evolving, with multiple devices approved over the past decade. Currently available devices fall into two broad categories of treatment methods: catheter-directed thrombolysis and percutaneous suction thrombectomy. Catheter-directed thrombolysis is the infusion of thrombolytic agents directly into the occluded pulmonary arteries to increase local delivery and decrease the total dose. Suction thrombectomy involves the use of small- or large-bore catheters to mechanically aspirate a clot from the pulmonary arteries without the need for a thrombolytic agent. A thorough understanding of the various risk stratification schemes and the available evidence for each device is critical for optimal treatment of this complex entity. Multiple ongoing studies will improve our understanding of the role of catheter-based therapy for acute PE in the next 5-10 years. A multidisciplinary approach through PE response teams has become the management standard at most institutions. An invited commentary by Bulman and Weinstein is available online. Online supplemental material is available for this article. ^©RSNA, 2022.

VA-ECMO-assisted aspiration thrombectomy in a patient presenting with acute massive PE with absolute contraindications to thrombolytics

Massive pulmonary embolism (PE) is a life-threatening complication of major surgery with a mortality rate up to 50%. First-line therapy for massive PE is systemic thrombolytics, but surgical patients are at high bleeding risk with absolute contraindications. As surgical thrombectomy carries a high burden of morbidity and mortality, endovascular interventions are becoming more common in these clinical scenarios. We report a case of a neurosurgical patient whose postoperative course was complicated by massive PE and subsequent cardiac arrest that required emergent venoarterial extracorporeal membrane oxygenation, followed by aspiration thrombectomy with the Inari FlowTriever Device (Inari Medical). The patient had immediate hemodynamic improvement with eventual recovery to baseline functional status.

Initial experience and early outcomes of the management of acute pulmonary embolism using the FlowTriever mechanical thrombectomy device

BACKGROUND

Submassive and massive pulmonary embolism is associated with a high risk of complications. We aimed to evaluate our initial experience with a mechanical thrombectomy device in the management of these patients.

METHODS

A single-center, retrospective study was performed in patients with acute submassive and massive pulmonary embolism treated with the FlowTriever device (Inari Medical, Irvine, CA, USA) between June 2019 and November 2020. Clinical and technical parameters were analyzed during the hospitalization and at 30- and 180-days after the procedure.

RESULTS

Fourteen patients were evaluated with a median (IQR) age of 60 (50-69) years and 64% were male. All had right heart strain as the main indication for thrombectomy. The procedure duration and fluoroscopic time was 52 (37-89) and 13 (9-24) minutes, respectively. There was 100% technical success, and the pulmonary arterial pressure went from 60 (48-65) mmHg to 40 (34-47) mmHg. Thrombolysis was used in two patients and nine patients required intensive care. 100% experienced improvement in symptoms at the time of discharge. There were no device-related complications, major bleeding events, myocardial infarctions, or deaths. Preprocedural hemoglobin was 13 (12-15) g/dL, and predischarge was 12 (10-13) g/dL. Overall postprocedural length of stay was three (2-6) days. All the patients were discharged with oral anticoagulation. There were no device-related complications or recurrence of embolism at 30 and 180 days.

CONCLUSIONS

The mechanical thrombectomy device for submassive and massive pulmonary embolism is promising and appears a safe and effective procedure with 100% technical success, no complications, short intensive care requirement/stay, and good early clinical outcomes.

Pulmonary Embolism and Pregnancy-Challenges in Diagnostic and Therapeutic Decisions in High-Risk Patients

Diagnosis of acute PE in pregnant women with haemodynamic instability is following the general integrated risk-adapted diagnostic algorithm and starts with bedside echocardiography to assess RV function. If RV dysfunction is identified, a prompt and immediate reperfusion without further imaging should be initiated. Although pregnancy is listed as a relative contraindication of systemic thrombolysis, in pregnant women with acute PE and haemodynamic instability thrombolysis must be considered. In those cases, other treatment strategies as surgical embolectomy or catheter-directed low-dose thromboylysis or percutaneous thrombectomy should be taken into consideration as well. A multidisciplinary team with experience of PE management in pregnancy should be consulted to reach consensus on the best treatment approach.

Multimodal thrombectomy device for treatment of acute deep venous thrombosis

Deep vein thrombosis (DVT) is a potentially deadly medical condition that is costly to treat and impacts thousands of Americans every year. DVT is characterized by the formation of blood clots within the deep venous system of the body. If a DVT dislodges it can lead to venous thromboembolism (VTE) and pulmonary embolism (PE), both of which can lead to significant morbidity or death. Current treatment options for DVT are limited in both effectiveness and safety, in part because the treatment of the DVT cannot be confined to a defined sequestered treatment zone. We therefore developed and tested a novel thrombectomy device that enables the sequesteration of a DVT to a defined treatment zone during fragmentation and evacuation. We observed that, compared to a predicate thrombectomy device, the sequestered approach reduced distal DVT embolization during ex vivo thrombectomy. The sequestered approach also facilitated isovolumetric infusion and suction that enabled clearance of the sequestered treatment zone without significantly impacting vein wall diameter. Results suggest that our novel device using sequestered therapy holds promise for the treatment of high risk large-volume DVTs.

Endovascular Management of Venous Thromboembolic Disease in the Oncologic Patient Population

PURPOSE OF REVIEW

Venous thromboembolic disease causes significant mortality and morbidity in the oncologic patient population. Recently, minimally invasive endovascular technologies have been developed as an adjunct to antithrombotic therapy for the management of DVT and PE. The current and potential roles for endovascular treatment of cancer-associated venous thromboembolism (VTE) will be reviewed in this article.

RECENT FINDINGS

The recent NCCN guidelines recommend endovascular therapy in patients eligible for therapeutic anticoagulation who present with life-, organ-, or limb-threatening thrombosis. However, symptomatic non-life-threatening VTE can negatively affect QOL and physical function, both of which have prognostic implications in the cancer population. Endovascular therapies have been shown to improve physical function and QOL in prospective trials performed in a non-oncologic patient population as well as small retrospective studies in the cancer population. In addition to treating life- and limb-threatening thrombosis, endovascular therapy for VTE can improve QOL and physical function in comparison to anticoagulation alone. Prospective trials are warranted to assess the benefit of endovascular therapy for quality of life-years, performance status, and overall survival in the oncologic patient population.

FlowTriever Retrieval System for the treatment of pulmonary embolism: overview of its safety and efficacy

INTRODUCTION

Pulmonary embolism (PE) is the third leading cause of cardiovascular mortality. There has been little change in PE mortality rates over the past two decades making this an appealing area for innovation and development.

AREAS COVERED

While anticoagulation (AC) and systemic thrombolysis (ST) are the mainstay treatments for high-risk PE and intermediate-high-risk PE with decompensation, advancements in catheter- based therapies offer potential alternatives. Areas covered here will include present guidelines for PE treatment and the landscape of catheter-directed therapies with a focus on the FlowTriever (FT) Retrieval System. Available safety and efficacy data will be reviewed. An online search via Google Scholar and PubMed with the keywords INARI Flowtriever, venous thromboembolism, and pulmonary embolism, alongside bibliographies of published articles, was undertaken as a review of the literature on the FlowTriever system for this device overview.

EXPERT OPINION

The five-year outlook on the role of catheter-directed therapies in the management of PE includes continued innovation in catheter-directed therapies and a number of high-quality trials on the horizon.

Catheter-directed therapy in pulmonary embolism

Acute pulmonary embolism (PE) is a life-threatening condition with high mortality rates and potential long-term sequelae. Systemic thrombolysis has been virtually the only therapeutic option available for patients with hemodynamic instability over decades. Recently, interventional therapy of PE has gained increasing interest. Multiple devices were developed; these include devices for local thrombolysis, thrombus fragmentation, thrombus aspiration, and combined approaches. However, the available evidence is limited to mostly small, nonrandomized studies. In these studies, safety and efficacy data from patients with intermediate or high-risk PE are promising. However, due to the lack of adequately powered randomized trials, interventional treatment of intermediate or high-risk PE cannot be recommended as standard-of-care. The decision on whether and how to perform a catheter-based intervention should therefore be left to the discretion of the local team, depending on the patients' clinical status, bleeding risk, local expertise, and available devices. The implementation of local multidisciplinary PE response teams is recommended by international guidelines to provide the best possible treatment.

In-Hospital Mortality and Related Outcomes for Elevated Risk Acute Pulmonary Embolism Treated With Mechanical Thrombectomy Versus Routine Care

PURPOSE

To compare in-hospital mortality and other hospitalization related outcomes of elevated risk patients (Pulmonary Embolism Severity Index [PESI] score of 4 or 5, and, European Society of Cardiology [ESC] classification of intermediate-high or high risk) with acute central pulmonary embolism (PE) treated with mechanical thrombectomy (MT) using the Inari FlowTriever device versus those treated with routine care (RC).

MATERIALS AND METHODS

Retrospective data was collected of all patients with acute, central PE treated at a single institution over 2 concurrent 18-month periods. All collected patients were risk stratified using the PESI and ESC Guidelines. The comparison was made between patients with acute PE with PESI scores of 4 or 5, and, ESC classification of intermediate-high or high risk based on treatment type: MT and RC. The primary endpoint evaluated was in-hospital mortality. Secondary endpoints included intensive care unit (ICU) length of stay, total hospital length of stay, and 30-day readmission.

RESULTS

Fifty-eight patients met inclusion criteria, 28 in the MT group and 30 in the RC group. Most RC patients were treated with systemic anticoagulation alone (24 of 30). In-hospital mortality was significantly lower for the MT group than for the RC group (3.6% vs 23.3%, P < .05), as was the average ICU length of stay (2.1 ± 1.2 vs 6.1 ± 8.6 days, P < .05). Total hospital length of stay and 30-day readmission rates were similar between MT and RC groups.

CONCLUSION

Initial retrospective comparison suggests MT can improve in-hospital mortality and decrease ICU length of stay for patients with acute, central PE of elevated risk (PESI 4 or 5, and, ESC intermediate-high or high risk).

Multisystem thromboembolism in a COVID-19 patient: a case report

Hypercoagulability has been found in patients diagnosed with the novel coronavirus 19 (COVID-19) and has been identified as a major cause of morbidity and mortality. Herein, we report the challenge in managing a patient presenting with a 5 day history of COVID-19 diagnosis, complicated by deep venous thrombosis, pulmonary embolism and ischemic stroke in the setting of atrial septal aneurysm, presumed patent foramen ovale and paradoxical embolism, identified to have clots in transit on echocardiogram. The application of anticoagulation was felt to be high risk. The patient was transferred to a tertiary facility where the patient underwent thrombus aspiration and was eventually complicated by hemorrhagic conversion of the stroke.

Successful removal of a Life-threatening PE using the INARI flow triever device

The authors report a case of a 75-year-old male with pulmonary embolism (PE) successfully treated using the INARI FlowTriever System, a mechanical thrombectomy device. Imaging confirmed deep vein thrombosis and PE presented after two days of left lower extremity (LLE) pain and dyspnea on exertion with history of peripheral vascular disease, coronary artery disease, insulin dependent diabetes mellitus, hyperlipidemia and LLE percutaneous coronary intervention with coronary stent placement. PE treatment with single session clot burden reduction resulted in immediate improvement in oxygenation and echocardiogram confirmed relief of right heart strain. The patient's immediate hemodynamic improvement without thrombolytic therapy, which can take hours for morbidity reduction, supports the expansion of the use of thrombectomy devices for the treatment of submassive symptomatic PE in clinical practice, with further research indicated.

Catheter-based interventions versus medical and surgical approaches in acute pulmonary embolism

OBJECTIVE

Catheter-based intervention (CBI) has become an increasingly popular option for treating pulmonary embolism (PE); however, the real benefits are unknown. The purpose of the present study was to compare the outcomes of patients treated with CBI with the outcomes of those treated with medical or surgical approaches.

METHODS

We performed a retrospective analysis of patients admitted from October 2015 to December 2017 with a diagnosis of acute PE. We compared patients aged ≥18 years with a diagnosis of acute PE treated with CBI against a control group identified by propensity score matching. The control group was divided into those who had undergone surgical pulmonary embolectomy (SPE) as the surgical group and those who had not undergone SPE as the medical group. The primary outcome was mortality (in-hospital and overall mortality). The secondary outcomes were major bleeding, length of hospital stay, thrombus resolution, right ventricle improvement in systolic function and dilatation, and recurrent PE.

RESULTS

Of the 108 patients, 30 were in the CBI group and 78 were in the control group (62 in the medical group and 16 in the surgical group). The patient characteristics on admission were similar, except for the body mass index, which was greater in the CBI group (P = .03). No difference was found in clinical severity, clot burden, right ventricle function, or biomarkers. Recurrent PE was less frequent in the CBI group than in the medical group (0% vs 6.4%). Otherwise, no significant differences were found in the outcomes between the CBI and medical groups. When CBI was compared with the surgical group, SPE was associated with improved mortality (0% vs 16.6%) but a longer median length of hospital stay (median, 7 days; interquartile range, 3-12 days; vs median, 8 days; interquartile range, 6.5-17 days).

CONCLUSIONS

The use of CBI reduced the number of recurrent PE events compared with the medically treated patients; however, the mortality was higher than that in the surgical group.

Endovascular therapies for pulmonary embolism

Purpose

The aim of this article is to define the place of new endovascular methods for the management of pulmonary embolisms (PE), on the basis of a multidisciplinary consensus.

Method and results

Briefly, from the recent literature, for high-risk PE presenting with shock or cardiac arrest, systemic thrombolysis or embolectomy is recommended, while for lowrisk PE, anticoagulation alone is proposed. Normo-tense patients with PE but with biological or imaging signs of right heart dysfunction constitute a group known as “at intermediate risk” for which the therapeutic strategy remains controversial. In fact, some patients may require more aggressive treatment in addition to the anticoagulant treatment, because approximately 10% will decompensate hemodynamically with a high risk of mortality. Systemic thrombolysis may be an option, but with hemorrhagic risks, particularly intra cranial. Various hybrid pharmacomechanical approaches are proposed to maintain the benefits of thrombolysis while reducing its risks, but the overall clinical experience of these different techniques remains limited. Patients with high intermediate and high risk pulmonary embolism should be managed by a multidisciplinary team combining the skills of cardiologists, resuscitators, pneumologists, interventional radiologists and cardiac surgeons. Such a team can determine which intervention – thrombolysis alone or assisted, percutaneous mechanical fragmentation of the thrombus or surgical embolectomy – is best suited to a particular patient.

Conclusions

This consensus document define the place of endovascular thrombectomy based on an appropriate risk stratification of PE.

Current Endovascular Treatment Options in Acute Pulmonary Embolism

Acute pulmonary embolism (PE) is a significant cause of mortality and morbidity across the globe. Over the last few decades, there have been major therapeutic advances in acute PE management, including catheter-based therapy. However, the effectiveness of catheter-based therapy in acute PE is not supported by Level I evidence, making the use of this promising treatment rather controversial and ambiguous. In this paper, we discuss the risk stratification of acute PE and review the medical and endovascular treatment options. We also summarize and review the data supporting the use of endovascular treatment options in acute PE and describe the potential role of the PE response team.

Safety of the Inari FlowTriever device for mechanical thrombectomy in patients with acute submassive and massive pulmonary embolism and contraindication to thrombolysis

Objectives:

This report evaluates the safety of percutaneous mechanical thrombectomy with the Inari FlowTriever System (Inari Medical, Irvine, California) for the treatment of acute massive/submassive pulmonary embolism (PE) specifically in therapeutically anticoagulated patients with contraindication to thrombolysis.

Material and Methods:

A single-center retrospective chart review was performed on patients with contraindication to thrombolysis and massive/submassive PE who underwent FlowTriever thrombectomy between 2017 and 2019. Primary outcomes included procedure or device-related complications within 30 days of discharge. Secondary outcomes included technical and clinical success defined by improvement in mean pulmonary artery pressure (PAP), oxygen saturation, and heart rate.

Results:

Thirteen patients with contraindication to thrombolysis received FlowTriever thrombectomy with technical success achieved in all cases. Zero major or minor adverse events, technical complications, delayed procedure-related complications, or deaths within 30 days of hospital discharge occurred. Mean PAP decreased significantly by 19.1% (32.5 ± 13.3 mmHg to 26.3 ± 12.4 mmHg; P = 0.0074, 95% confidence interval (CI) 2.0–10.5 mmHg). Oxygen saturation improved post-procedure (increased 3.9 ± 3.8%; p = 0.0032, 95% CI 1.6– 6.1%) as did heart rate (decreased 22.2 ± 17.0 bpm; P < 0.001, 95% CI 11.9–32.4 bpm). Anticoagulation was maintained throughout every procedure and all patients were closed with purse-string suture only.

Conclusion:

FlowTriever mechanical thrombectomy appears safe for acute PE in therapeutically anticoagulated patients with contraindications to thrombolytic therapy. These patients may experience immediate hemodynamic improvements similar to those reported in other studies. Further data are needed to prospectively evaluate long-term safety in this population.

Bleeding, death, and costs of care during hospitalization for acute pulmonary embolism: Insights from the Saint Luke's Outcomes of Pulmonary Embolism (SLOPE) study

Limited data exist that comprehensively describe the practical management, in-hospital outcomes, healthcare resource utilization, and rates of post-hospital readmission among patients with submassive and massive pulmonary embolism (PE). Consecutive discharges for acute PE were identified from a single health system over 3 years. Records were audited to confirm presence of acute PE, patient characteristics, disease severity, medical treatment, and PE-related invasive therapies. Rates of in-hospital major bleeding and death, hospital length of stay (LOS), direct costs, and hospital readmission are reported. From January 2016 to December 2018, 371 patients were hospitalized for acute massive or submassive PE. In-hospital major bleeding (12.1%) was common, despite low utilization of systemic thrombolysis (1.8%) or catheter-directed thrombolysis (3.0%). In-hospital death was 10-fold higher among massive PE compared to submassive PE (36.6% vs 3.3%, p < 0.001). Massive PE was more common during hospitalizations not primarily related to venous thromboembolism, including hospitalizations primarily for sepsis or infection (26.8% vs 8.2%, p = 0.001). Overall, the median LOS was 6.0 days (IQR, 3.0-11.0) and the median standardized direct cost of admissions was $10,032 (IQR, $4467-$20,330). Rates of all-cause readmission were relatively high throughout late follow-up but did not differ between PE subgroups. Despite low utilization of thrombolysis, in-hospital bleeding remains a common adverse event during hospitalizations for acute PE. Although massive PE is associated with high risk for in-hospital bleeding and death, those successfully discharged after a massive PE demonstrate similar rates of readmission compared to submassive PE into late follow-up.

FlowTriever System for mechanical thromboembolectomy

The systemic or catheter-directed infusion of thrombolytics benefits patients with massive and probably submassive pulmonary embolism. However, the risk of bleeding may offset benefits in a substantial number of patients. Percutaneous mechanical thromboembolectomy is an alternative to thrombolysis in those patients with contraindications to the lytic therapy, also potentially a way to avoid systemic or catheter-directed infusion of the thrombolytic all together. The Inari FlowTriever System (Inari Medical Inc, CA, USA) is the first US FDA-cleared large-bore aspiration thrombectomy device with pulmonary embolism thrombectomy indication. This article is a review of the FlowTriever System, its clinical use, current supportive literates and future research directions.

Proposed Algorithm for Treatment of Pulmonary Embolism in COVID-19 Patients

There is mounting evidence that COVID-19 patients may possess a hypercoagulable profile that increases their risk for thromboembolic complications, including pulmonary embolism (PE). PE has been associated with an increase in morbidity, mortality, prolonged ventilation, and extended ICU admissions. Intervention is warranted in some patients who develop acute massive and submassive PEs. However, the development of PE in COVID-19 patients is often complicated by such factors as delay of diagnosis, confounding medical conditions, and strict isolation precautions. In addition, depleted cardiopulmonary reserve and prone positioning can make management of PE in these patients especially challenging for the physician. In this article, we review current understanding of PE in COVID-19 patients, summarize consensus data regarding the treatment of PE, and propose an algorithm to guide the management of COVID-19 patients with PE.

Catheter-directed therapies for pulmonary embolism: considerations for patients with patent foramen ovale

Pulmonary embolism can be fatal, especially in high-risk patients who have contraindications to systemic thrombolysis or surgical embolectomy. For this population, interventionalists can provide catheter-directed therapies, including catheter-directed thrombolysis and thrombectomy, using a wide array of devices. Endovascular treatment of pulmonary embolism shows great promise through fractionated thrombolytic drug delivery, fragmentation, and aspiration mechanisms with thrombectomy devices. Although successful outcomes have been reported after using these treatments, evidence is especially limited in patients with both a patent foramen ovale (PFO) and acute pulmonary embolism. In patients with PFO, it is important to consider whether catheter-directed therapy is appropriate or whether surgical embolectomy should instead be performed. An increased risk of paradoxical embolus in these patients supports the use of diagnostic echocardiography with possible surgical closure of PFO after one episode of pulmonary embolism. Percutaneous PFO closure, which can be performed at the time of catheter-based therapy, theoretically reduces risk of future paradoxical embolization, although more data are needed before making a recommendation for this specific group of patients.

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.