Aspiration Thrombectomy for Treatment of Acute Massive and Submassive Pulmonary Embolism: Initial Single-Center Prospective Experience

Comparison of Safety and Efficacy of Aspiration Thrombectomy and Ultrasound Accelerated Thrombolysis for Management of Pulmonary Embolism: A Systematic Review and Meta-Analysis

PURPOSE

To compare the safety and efficacy of mechanical thrombectomy (MT) and ultrasound-accelerated thrombolysis (USAT) in pulmonary embolism (PE) management by performing a systematic review of the literature.

MATERIALS AND METHODS

The PubMed database was searched to identify articles on Inari's FlowTriever and Penumbra's Indigo mechanical thrombectomy devices (Group A) and the Ekos Endovascular system (Group B). Outcomes variables analyzed include pre- and post-procedure RV/LV ratio, pre- and post-procedure pulmonary artery pressure, hospital length of stay, technical success, specific complications, and mortality rate. Mean values were calculated using the weighted mean approach. RevMan Version 5.4 (Cochrane Collaboration) was used to perform the meta-analysis for this study. Cochrane Collaboration's Risk of Bias (RoB 2.0) approach was used to perform a quality assessment of the included articles in order to verify the validity and reliability of the research.

RESULTS

27 studies were in Group A and 28 studies pertained to Group B. There were 1662 patients in Group A and 1273 patients in Group B. Both groups had similar technical success (99.6% vs 99.4%). Thrombectomy showed longer mean procedure time (73.03 ± 14.57 min vs 47.35 ± 3.15 min), lower mean blood loss (325.20 ± 69.15 mL vs 423.05 ± 64.95 mL), shorter mean ICU stay (2.35 ± 1.64 days vs 3.22 ± 1.27 days), and shorter mean overall hospital stay (6.94 ± 4.38 days vs 7.23 ± 2.31 days). EKOS showed greater mean change in Miller Index (9.05 ± 3.35 vs 4.91 ± 3.70) and greater mean change in pulmonary artery pressure (14.17 ± 6.35 mmHg vs 8.11 ± 4.39 mmHg).

CONCLUSION

Ultrasound accelerated thrombolysis and percutaneous mechanical thrombectomy are effective therapies for pulmonary embolism with comparable clinical outcomes.

Episode Care Costs Following Catheter-Directed Reperfusion Therapies for Pulmonary Embolism: A Literature-Based Comparative Cohort Analysis

This analysis aimed to estimate 30-day episode care costs associated with 3 contemporary endovascular therapies indicated for treatment of pulmonary embolism (PE). Systematic literature review was used to identify clinical research reporting costs associated with invasive PE care and outcomes for ultrasound-accelerated thrombolysis (USAT), continuous-aspiration mechanical thrombectomy (CAMT), and volume-controlled-aspiration mechanical thrombectomy (VAMT). Total episode variable care costs were defined as the sum of device costs, variable acute care costs, and contingent costs. Variable acute care costs were estimated using methodology sensitive to periprocedural and postprocedural resource allocation unique to the 3 therapies. Contingent costs included expenses for thrombolytics, postprocedure bleeding events, and readmissions through 30 days. Through February 28, 2023, 70 sources were identified and used to inform estimates of 30-day total episode variable costs. Device costs for USAT, CAMT, and VAMT were the most expensive single component of total episode variable costs, estimated at $5,965, $10,279, and $11,901, respectively. Costs associated with catheterization suite utilization, intensive care, and hospital length of stay, along with contingent costs, were important drivers of total episode costs. Total episode variable care costs through 30 days were $19,146, $20,938, and $17,290 for USAT, CAMT, and VAMT, respectively. In conclusion, estimated total episode care costs after invasive treatment for PE are heavily influenced by device expense, in-hospital care, and postacute care complications. Regardless of device cost, strategies that avoid thrombolytics, reduce the need for intensive care unit care, shorten length of stay, and reduce postprocedure bleeding and 30-day readmissions contributed to the lowest episode costs.

Contemporary Management of Pulmonary Embolism: Review of the Inferior Vena Cava filter and Other Endovascular Devices

Inferior vena cava (IVC) filters and endovascular devices are used to mitigate the risk of pulmonary embolism in patients presenting with lower extremity venous thromboembolism in whom long-term anticoagulation is not a good option. However, the efficacy and benefit of these devices remain uncertain, and controversies exist. This review focuses on the current use of IVC filters and other endovascular therapies in clinical practice. The indications, risks, and benefits are discussed based on current data. Further research and randomized controlled trials are needed to characterize the patient population that would benefit most from these interventional therapies.

Hybrid Thrombectomy and Central Extracorporeal Membrane Oxygenation for Massive Pulmonary Embolism in a Child

We describe a hybrid thrombectomy and central extracorporeal membrane oxygenation for a child in cardiogenic shock due to a massive pulmonary embolism.

A cross-sectional study of outcomes for patients undergoing mechanical thrombectomy for pulmonary embolism during 2018-2022: Insights from the PINC AI Healthcare Database

Background and Aims

Mechanical thrombectomy (MT) treatments for pulmonary embolism (PE) have yet to be compared directly. We aimed to determine if patient outcomes varied following treatment of PE with different MT devices.

Methods

All PE encounters with an index treatment of MT between January 2018 and March 2022 were analyzed for in-hospital mortality, discharge to home, and 30-day readmission outcomes in the PINC AI™ Healthcare Database. MT devices used in each encounter were extracted from hospital charge description free-text fields using keyword text and fuzzy matching. Unadjusted and adjusted logistic regression was used to model outcomes by device.

Results

A total of 5893 encounters were identified using MT as the sole index PE treatment and 1812 using MT with another treatment. Of these, 41% had insufficient information to identify the devices used (unspecified MT), 33% used the FlowTriever System (large-bore volume-controlled aspiration MT), 23% the Indigo System (continuous aspiration MT), and 3% some other MT. Large-bore volume-controlled aspiration MT was used with other treatments 13% of the time compared with 23% and 39% for unspecified MT and continuous aspiration MT, respectively. Adjusted logistic regression modeling revealed the odds of in-hospital mortality were significantly higher for patients treated with unspecified MT ([OR] = 1.42, 95% confidence interval [CI]: [1.10-1.83], p = 0.008) or continuous aspiration MT (OR = 1.63, 95% CI: [1.21-2.19], p = 0.001) compared with large-bore volume-controlled aspiration MT. Discharge to home was significantly lower in these same groups (OR = 0.84, 95% CI: [0.73-0.96], p = 0.01, and OR = 0.63, 95% CI: [0.53-0.74], p < 0.001, respectively), but readmission risks at 30 days were comparable (OR = 1.08, 95% CI: [0.84-1.38], p = 0.56, and OR = 1.20, 95% CI: [0.89-1.62], p = 0.24, respectively).

Conclusion

PE outcomes and treatment patterns differ significantly based on the type of MT utilized. Clinical studies directly comparing MT treatments are needed to further understand optimal treatment of PE.

Percutaneous interventions for pulmonary embolism

Pulmonary embolism (PE) ranks as a leading cause of in-hospital mortality and the third most common cause of cardiovascular death. The spectrum of PE manifestations varies widely, making it difficult to determine the best treatment approach for specific patients. Conventional treatment options include anticoagulation, thrombolysis, or surgery, but emerging percutaneous interventional procedures are being investigated for their potential benefits in heterogeneous PE populations. These novel interventional techniques encompass catheter-directed thrombolysis, mechanical thrombectomy, and hybrid approaches combining different mechanisms. Furthermore, inferior vena cava filters are also available as an option for PE prevention. Such interventions may offer faster improvements in right ventricular function, as well as in pulmonary and systemic haemodynamics, in individual patients. Moreover, percutaneous treatment may be a valid alternative to traditional therapies in high bleeding risk patients and could potentially reduce the burden of mortality related to major bleeds, such as that of haemorrhagic strokes. Nevertheless, the safety and efficacy of these techniques compared to conservative therapies have not been conclusively established. This review offers a comprehensive evaluation of the current evidence for percutaneous interventions in PE and provides guidance for selecting appropriate patients and treatments. It serves as a valuable resource for future researchers and clinicians seeking to advance this field. Additionally, we explore future perspectives, proposing "percutaneous primary pulmonary intervention" as a potential paradigm shift in the field.

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.

Role of Intravascular Ultrasound in Pulmonary Embolism Patients Undergoing Mechanical Thrombectomy: A Systematic Review

BACKGROUND

Traditionally, mechanical thrombectomy performed for pulmonary embolism (PE) necessitates the utilization of iodinated contrast. Intravascular ultrasound (IVUS) has been used as a diagnostic and therapeutic modality in the management of acute high and intermediate-risk PE. Recently, with the shortage of contrast supplies and the considerable incidence of contrast-induced acute kidney injury (CI-AKI), other safer and more feasible IVUS methods have become desirable. The purpose of this systematic review was to evaluate the importance of IVUS in patients with PE undergoing thrombectomy.

METHODS

Medline/PubMed, Embase, Scopus, and Google Scholar were searched for review studies, case reports, and case series. Clinical characteristics, outcomes and the usage of IVUS-guided mechanical thrombectomy during the treatment of acute high and intermediate-risk PE were examined in a descriptive analysis.

RESULTS

In this systematic review, we included one prospective study, two case series, and two case reports from July 2019 to May 2023. A total of 39 patients were evaluated; most were female (53.8%). The main presenting symptoms were dyspnea and chest pain (79.5%); three patients (7.9%) presented with syncope, one with shock and one with cardiac arrest. Biomarkers (troponin and BNP) were elevated in 94.6% of patients. Most patients (87.2%) had intermediate-risk PE, and 12.8% had high-risk PE. All patients presented with right-heart strain (RV/LV ratio ≥ 0.9, n = 39). Most patients (56.4%) had bilateral PE. Mechanical thrombectomy was performed using IVUS without contrast utilization in 39.4% of the patients. After the initial learning curve, contrast usage decreased gradually over time. There was a significant decrease in the composite mean arterial pressure immediately following IVUS-guided thrombectomy from 35.1 ± 7.2 to 25.2 ± 8.3 mmHg (p < 0.001). Post-procedure, there was no reported (0%) CI-AKI, no all-cause mortality, no major bleeding, or other adverse events. There was a significant improvement in symptoms and RV function at the mean follow-up.

CONCLUSIONS

New evidence suggests that IVUS-guided mechanical thrombectomy is safe, with visualization of the thrombus for optimal intervention, and reduces contrast exposure.

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.

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.

Catheter-Based Therapies Decrease Mortality in Patients With Intermediate and High-Risk Pulmonary Embolism: Evidence From Meta-Analysis of 65,589 Patients

Background

Catheter-directed therapies (CDT) are an alternative to systemic thrombolysis (ST) in pulmonary embolism (PE) patients, but the mortality benefit of CDT is unclear.

Objective

We conducted a systematic review with meta-analysis to compare the efficacy and safety of CDT and ST in intermediate-high and high-risk PE.

Methods

We included (P) participants, adult PE patients; (I) intervention, CDT; (C) comparison, ST; (O) outcomes, mortality, complications, in-hospital treatment, and length of hospital stay; (S) study design, randomized controlled trials (RCTs), or cohort comparing CDT and ST. The primary endpoint was 30-day mortality. Secondary outcomes included treatment-related complications including bleeding, the use of hospital resources, and length of hospital stay.

Results

Eleven studies including 65,589 patients met the inclusion criteria. Thirty-day mortality was lower in the CDT group, compared to ST group [7.3 vs. 13.6%; odds ratio (OR) = 0.51, 95% confidence interval (CI) 0.38–0.69, p < 0.001]. The rates of myocardial injury, cardiac arrest, and stroke were lower in CDT group, compared to ST group (p < 0.001 for all). The rates of any major bleeding, intracranial hemorrhage, hemoptysis, and red blood cell transfusion were lower in patients treated with CDT, compared to ST (p ≤ 0.01 for all). Extracorporeal life support was used more often in patients treated with CDT, compared to ST (0.5 vs. 0.2%, OR = 2.52, 95% CI 1.88–3.39, p < 0.001). The use of hospital resources and length of hospital stay were comparable in both groups.

Conclusion

CDT might decrease mortality in patients with intermediate-high and high-risk PE and were associated with fewer complications, including major bleeding.

Pulmonary Embolism in Transit Across a Patent Foramen Ovale

A pulmonary embolism (PE) is an obstruction in a pulmonary artery, and a saddle PE occurs when the obstruction is lodged in the main pulmonary trunk and spans the left and right pulmonary arteries. The current case study describes complications of a thrombus in transit across a patent foramen ovale (PFO). A 35-year-old female presented to the emergency department after a nontraumatic syncopal fall. She had recently returned from a cross-country flight 10 days before and had noticed left calf tenderness when exiting the plane. Vitals were notable for sinus tachycardia at 120 bpm. An electrocardiogram indicated an S1Q3T3 pattern, and chest computed tomographic angiography was positive for a saddle PE. A 2D (two-dimensional) transthoracic echocardiogram showed right ventricular free wall hypokinesis and McConnell’s sign. Echocardiogram findings were concomitant with a thrombus in transit across the interatrial septum, indicating a possible PFO. An emergency pulmonary embolectomy with cardiopulmonary bypass and closure of her PFO was performed the following morning and complicated by cardiogenic shock and subsequent cardiac arrest. The patient was resuscitated in the operating room but failed to be removed from cardiopulmonary bypass, requiring low-dose inotropic support and venoarterial extracorporeal membrane oxygenation flow at 4 L/min. After a repeat right pulmonary artery thrombectomy and two subsequent transesophageal echocardiograms indicated stable right ventricular systolic function, decannulation was performed. The patient was discharged on day 17 with long-term anticoagulation and home healthcare. In the current case report, the patient’s unstable and deteriorating condition was complicated by unusual findings of a thrombus in transit across a PFO. These additional echocardiogram findings represented an unusual case that warranted surgical treatment instead of systemic thrombolysis therapy because of the increased risk of systemic clot embolization.

Complications of penumbra indigo aspiration device in pulmonary embolism: Insights from MAUDE database

BACKGROUND

The Penumbra Indigo aspiration system (Penumbra Inc., Alameda, CA, USA) is a suction embolectomy device that was cleared by the Food and Drug Administration for use in acute pulmonary embolism (PE). While this device has proven to be safe in clinical trials, real-world data are minimal.

METHODS

The "Manufacturer and User Facility Device Experience" MAUDE database was queried for reports of Penumbra indigo system from January 2020 to August 2021.

RESULTS

A total of 2118 reports were found during the study period. After the exclusion of duplicate and incomplete reports as well as reports not related to PE, our final cohort included 67 reports related to Penumbra indigo device failure. The most common failure mode was Lightning unit malfunction (35.8%, n = 24) followed by rotating hemostasis valve malfunction (31.3%, n = 21). Three (4.5%) patients died; two (3%) from fatal pulmonary vessel perforation, and one from fatal right-sided heart failure. There was one case (1.5%) of pericardial effusion, while there were no cases of hemoptysis or blood transfusion.

CONCLUSION

The overall number of reports in the MAUDE registry related to the Penumbra Indigo aspiration system is small (67 reports in 20 months). The most common reported failure mode was Lightning unit malfunction. These data serve to inform operators about potential issues when using the Penumbra Indigo thrombus aspiration system and identify areas on which to focus further device iteration.

Catheter-Directed Therapies in Patients with Pulmonary Embolism: Predictive Factors of In-Hospital Mortality and Long-Term Follow-Up

(1) Background: Catheter-directed therapies (CDT) may be considered for selected patients with pulmonary embolism (PE); (2) Methods: Retrospective observational study including all consecutive patients with acute PE undergoing CDT (mechanical or pharmacomechanical) from January 2010 through December 2020. The aim was to evaluate in-hospital and long-term mortality and its predictive factors; (3) Results: We included 63 patients, 43 (68.3%) with high-risk PE. All patients underwent mechanical CDT and, additionally, 27 (43%) underwent catheter-directed thrombolysis. Twelve (19%) patients received failed systemic thrombolysis (ST) prior to CDT, and an inferior vena cava (IVC) filter was inserted in 28 (44.5%) patients. In-hospital PE-related and all-cause mortality rates were 31.7%; 95% CI 20.6-44.7% and 42.9%; 95% CI 30.5-56%, respectively. In multivariate analysis, age > 70 years and previous ST were strongly associated with PE-related and all-cause mortality, while IVC filter insertion during the CDT was associated with lower mortality rates. After a median follow-up of 40 (12-60) months, 11 more patients died (mortality rate of 60.3%; 95% CI 47.2-72.4%). Long-term survival was significantly higher in patients who received an IVC filter; (4) Conclusions: Age > 70 years and failure of previous ST were associated with mortality in acute PE patients treated with CDT. In-hospital and long-term mortality were lower in patients who received IVC filter insertion.

Aspiration thrombectomy for acute pulmonary embolism with an intermediate-high risk

INTRODUCTION AND PURPOSE

The treatment of acute pulmonary embolism (PE) with an intermediate-high risk of mortality at 30 days is still not well defined, recommending the latest clinical guidelines of the European Society of Cardiology 2019 exclusively anticoagulant treatment, reducing the indication for mechanical thrombectomy to high-risk patients or intermediate-high risk patients with poor hemodynamic evolution. Our purpose is to determine the safety and efficacy of aspiration thrombectomy in intermediate-high risk patients with PE and to analyze possible differences in these results between hemodynamically unstable patients (massive PE) and hemodynamically stable patients (submassive PE).

METHODS

We analyzed all patients who underwent aspiration thrombectomy for PE at our tertiary university hospital during a 34-month period. We compared echocardiographic parameters (right ventricular diameter, tricuspid plane annular plane systolic excursion (TAPSE), S' wave, and pulmonary hypertension), respiratory parameters (PaO₂/FiO₂ ratio), and clinical parameters recorded before and 24h after the procedure. We also analyzed bleeding complications and mortality.

RESULTS

In the 42 patients included (16 with massive PE and 26 with submassive PE), aspiration thrombectomy resulted in significant improvements in right ventricular diameter, TAPSE, S' wave, andPaO₂/FiO₂ ratio. Of the 8 patients administered fibrinolysis, 4 developed bleeding complications. Only one direct complication of the procedure was observed (pulmonary artery rupture). Eight patients died in the acute phase.

CONCLUSIONS

Aspiration thrombectomy for PE is safe and effective, significantly improving respiratory and hemodynamic parameters in the first 24h after the procedure with a low rate of complications compared to fibrinolysis.

Indigo Aspiration System for Treatment of Pulmonary Embolism: Results of the EXTRACT-PE Trial

OBJECTIVES

This study sought to prospectively evaluate the safety and efficacy of the Indigo aspiration system in submassive acute pulmonary embolism (PE).

BACKGROUND

PE treatment with thrombolytics has bleeding risks. Aspiration thrombectomy can remove thrombus without thrombolytics, but data are lacking.

METHODS

This study was a prospective, single-arm, multicenter study that enrolled patients with symptomatic acute PE ≤14 days, systolic blood pressure ≥90 mm Hg, and right ventricular-to-left ventricular (RV/LV) ratio >0.9. The primary efficacy endpoint was change in RV/LV ratio from baseline to 48 h post-procedure on core lab-adjudicated computed tomography angiography. The primary safety endpoint was a composite of 48-h major adverse events: device-related death, major bleeding, and device-related serious adverse events (clinical deterioration, pulmonary vascular, or cardiac injury). All sites received Institutional Review Board approval.

RESULTS

A total of 119 patients (mean age 59.8 ± 15.0 years) were enrolled at 22 U.S. sites between November 2017 and March 2019. Median device insertion to removal time was 37.0 (interquartile range: 23.5 to 60.0) min. Two (1.7%) patients received intraprocedural thrombolytics. Mean RV/LV ratio reduction from baseline to 48 h post-procedure was 0.43 (95% confidence interval: 0.38 to 0.47; p < 0.0001). Two (1.7%) patients experienced 3 major adverse events. Rates of cardiac injury, pulmonary vascular injury, clinical deterioration, major bleeding, and device-related death at 48 h were 0%, 1.7%, 1.7%, 1.7%, and 0.8%, respectively.

CONCLUSIONS

In this prospective, multicenter study the Indigo aspiration system was associated with a significant reduction in the RV/LV ratio and a low major adverse event rate in submassive PE patients. Intraprocedural thrombolytic drugs were avoided in 98.3% of patients. (Evaluating the Safety and Efficacy of the Indigo aspiration system in Acute Pulmonary Embolism [EXTRACT-PE]; NCT03218566).

Management of Acute Pulmonary Embolism

Purpose of the Review

Over 100,000 cardiovascular-related deaths annually are caused by acute pulmonary embolism (PE). While anticoagulation has historically been the foundation for treatment of PE, this review highlights the recent rapid expansion in the interventional strategies for this condition.

Recent Findings

At the time of diagnosis, appropriate risk stratification helps to accurately identify patients who may be candidates for advanced therapeutic interventions. While systemic thrombolytics (ST) is the mostly commonly utilized intervention for high-risk PE, the risk profile of ST for intermediate-risk PE limits its use. Assessment of an individualized patient risk profile, often via a multidisciplinary pulmonary response team (PERT) model, there are various interventional strategies to consider for PE management. Novel therapeutic options include catheter-directed thrombolysis, catheter-based embolectomy, or mechanical circulatory support for certain high-risk PE patients. Current data has established safety and efficacy for catheter-based treatment of PE based on surrogate outcome measures. However, there is limited long-term data or prospective comparisons between treatment modalities and ST. While PE diagnosis has improved with modern cross-sectional imaging, there is interest in improved diagnostic models for PE that incorporate artificial intelligence and machine learning techniques.

Summary

In patients with acute pulmonary embolism, after appropriate risk stratification, some intermediate and high-risk patients should be considered for interventional-based treatment for PE.

Continuous Aspiration Thrombectomy in High- and Intermediate-High-Risk Pulmonary Embolism in Real-World Clinical Practice

Objectives

We sought to assess the technical and clinical feasibility of continuous aspiration catheter-directed mechanical thrombectomy (CDT) in patients with high- or intermediate-high-risk pulmonary embolism (PE).

Methods and Results

Fourteen patients (eight women and six men; age range: 29–71 years) with high- or intermediate-high-risk PE and contraindications to or ineffective systemic thrombolysis were prospectively enrolled between October 2018 and February 2020. The Indigo Mechanical Thrombectomy System (Penumbra, Inc., Alameda, California) was used as CDT device. Low-dose local thrombolysis (alteplase, 3–12 mg) was additionally applied in three patients. Technical and procedural success was achieved in 14 patients (100%). Complete or nearly complete clearance of pulmonary arteries was achieved in nine patients (64.3%), whereas partial clearance was achieved in five (35.7%). A significant improvement in the pre- and postprocedural patients' clinical status was observed in the following fields (median; interquartile range): heart rate (110; 100–120/min vs. 85; 80–90/min; p < 0.0001), systolic blood pressure (106; 90–127 mmHg vs. 123; 110–133 mmHg; p = 0.049), arterial oxygen saturation (88.5; 84.2–93% vs. 95.0; 93.8–95%, p = 0.0051), pulmonary artery systolic pressure (55; 44–66 mmHg vs. 42; 34–53 mmHg; p = 0.0015), Miller index score (21.5; 20–23 vs. 9.5; 8–13; p < 0.0001) and right ventricular/left ventricular ratio (1.3; 1.3–1.5 vs. 1.0; 0.9–1.0; p < 0.0001). No major periprocedural bleeding was detected.

Conclusions

CDT is a feasible and promising technique for management of high- or intermediate-high-risk PE to decrease thrombus burden, reduce right heart strain, and improve hemodynamic and clinical status. Some patients may benefit from simultaneous local low-dose thrombolytic therapy. Nevertheless, its criteria and role in CTD-managed patients require further elucidation.

COVID-19 as a Blood Clotting Disorder Masquerading as a Respiratory Illness: A Cerebrovascular Perspective and Therapeutic Implications for Stroke Thrombectomy

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) as the name suggests was initially thought to only cause a respiratory illness. However, several reports have been published of patients with ischemic strokes in the setting of coronavirus disease 2019 (COVID‐19). The mechanisms of how SARS‐CoV‐2 results in blood clots and large vessel strokes need to be defined as it has therapeutic implications. SARS‐CoV‐2 enters the blood stream by breaching the blood‐air barrier via the lung capillary adjacent to the alveolus, and then attaches to the angiotensin‐converting enzyme II receptors on the endothelial cells. Once SARS‐CoV‐2 enters the blood stream, a cascade of events (Steps 1‐8) unfolds including accumulation of angiotensin II, reactive oxygen species, endothelial dysfunction, oxidation of beta 2 glycoprotein 1, formation of antiphospholipid antibody complexes promoting platelet aggregation, coagulation cascade, and formation of cross‐linked fibrin blood clots, leading to pulmonary emboli (PE) and large vessel strokes seen on angiographic imaging studies. There is emerging evidence for COVID‐19 being a blood clotting disorder and SARS‐CoV‐2 using the respiratory route to enter the blood stream. As the blood‐air barrier is breached, varying degrees of collateral damage occur. Although antiviral and immune therapies are studied, the role of blood thinners in the prevention, and management of blood clots in Covid‐19 need evaluation. In addition to ventilators and blood thinners, continuous aspiration and clot retrieval devices (approved in Europe, cleared in the United States) or cyclical aspiration devices (approved in Europe) need to be considered for the emergent management of life‐threatening clots including PE and large vessel strokes.

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.

Catheter directed thrombolytic therapy and aspiration thrombectomy in intermediate pulmonary embolism with long term results

BACKGROUND

Catheter directed thrombolysis (CDT) and thrombectomy represent well established techniques for the treatment of intermediate pulmonary embolism (IPE). The long-term effect of catheter directed thrombolysis of IPE is unknown.

METHODS

Clinical, interventional and echocardiographic data from 80 consecutive patients with IPE who were treated with CDT were evaluated. Primary end-points were technical success and major adverse events. Secondary end-points were cardiovascular mortality, all-cause mortality, clinical success, rate of bleeding complications, improvement in pulmonary pressure and echocardiography parameters. CDT completed with alteplase (10 mg bolus and 1 mg/h maintenance dose) through a pig-tail catheter for 24 h. After 24 h, control pulmonary angiography was performed.

RESULTS

In total, 80 patients with a mean age of 59.0 ± 16.8 years were treated. CDT was successful after the first post-operative day in 72 (90%) patients, but thrombus aspiration and fragmentation was performed due to failed thrombolysis in 8 (10%) patients. Final technical and clinical success was reached in 79 (98.8%) and 77 (96.3%) patients, respectively. The mean CDT time in IPE was 27.8 ± 9.6 h. Invasive pulmonary pressure dropped from 57.5 ± 16.7 to 38.9 ± 13.5 (p < 0.001). A caval filter was implanted in 4 (5%) patients. The 1-year major adverse events and cardiovascular mortality rate was 4.0% and 1.4%, respectively. Access site complications (6 major and 6 minor) were encountered in 12 (16.2%) patients.

CONCLUSIONS

Catheter directed thrombolysis in submassive pulmonary embolism had excellent results. However, additional mechanical thrombectomy was necessary in some patients to achieve good clinical outcomes.

Interventional Therapies for Acute Pulmonary Embolism: Current Status and Principles for the Development of Novel Evidence: A Scientific Statement From the American Heart Association

Pulmonary embolism (PE) represents the third leading cause of cardiovascular mortality. The technological landscape for management of acute intermediate- and high-risk PE is rapidly evolving. Two interventional devices using pharmacomechanical means to recanalize the pulmonary arteries have recently been cleared by the US Food and Drug Administration for marketing, and several others are in various stages of development. The purpose of this document is to clarify the current state of endovascular interventional therapy for acute PE and to provide considerations for evidence development for new devices that will define which patients with PE would derive the greatest net benefit from their use in various clinical settings. First, definitions and limitations of commonly used risk stratification tools for PE are reviewed. An adjudication of risks and benefits of available interventional therapies for PE follows. Next, considerations for optimal future evidence development in this field are presented in the context of the current US regulatory framework. Finally, the document concludes with a discussion of the pros and cons of the rapidly expanding PE response team model of care delivery.

Endovascular therapy for acute severe pulmonary embolism

Acute pulmonary embolism (PE) is a major public health problem and accounts for 100,000-180,000 deaths per year in the United States. Current prognostic stratification separates acute PE into massive, submassive, and low-risk by the presence or absence of sustained hypotension, RV dysfunction, and myocardial necrosis. Massive, submassive and low-risk PE have mortality rates of 25-65%, 3%, and < 1%, respectively. In this review we will focus on therapies currently available to manage acute massive and submassive PE.

Outcomes of Catheter-Directed Therapy Plus Anticoagulation Versus Anticoagulation Alone for Submassive and Massive Pulmonary Embolism

BACKGROUND

Catheter-directed therapy (CDT) offers an alternative treatment to systemic thrombolysis for patients with massive and submassive pulmonary embolism.

METHODS

A retrospective review of 105 consecutive massive and submassive pulmonary embolisms over 2 years was performed. Thirty-six patients (9 massive, 27 submassive) were treated with CDT, consisting of aspiration thrombectomy (18), ultrasound-assisted thrombolysis (8), or both (10). Forty-three patients (8 massive, 35 submassive) were treated with heparin anticoagulation alone. Primary outcome was improvement of RV/LV ratio 24-48 hours after treatment. Safety outcomes included 90-day mortality, bleeding complications, and hospital readmissions. Subgroup analysis based on severity of RV dilation was performed.

RESULTS

Mean RV/LV ratio decreased from 1.91±0.61 to 1.28±0.45 (P < .001) in the CDT group and from 1.40 ± 0.37 to 1.25 ± 0.32 (P = .01) in the anticoagulation group. In submassive pulmonary embolisms with mild and moderate RV dilation (RV/LV ratio 0.9-1.9), RV/LV ratio was significantly lower in the CDT group at 24-48 hours (1.05 ± 0.38 vs 1.20 ± 0.31, P < .001). In submassive pulmonary embolisms with severe RV dilation (RV/LV ratio >1.9), no difference was noted between the 2 treatment groups. Ninety-day mortality (11% and 14%, p = 0.7) and incidence of major bleeding complications did not significantly differ between the 2 groups. Thirty-day readmission rates were 8% in the CDT group and 26% in the anticoagulation group (P = .04).

CONCLUSION

CDT for acute massive and submassive pulmonary embolism significantly improves RV/LV ratio at 24-48 hours compared with anticoagulation alone and may lower hospital readmission rates. CDT may be more advantageous in patients with mild to moderate RV dilation.

Aspiration thrombectomy for acute iliofemoral or central deep venous thrombosis

OBJECTIVE

The use of catheter-directed thrombolysis (CDT) may provide clinical benefit in patients with acute deep venous thrombosis (DVT), but significant doubt remains about its indications and risks. We assessed technical success in resolution of acute iliofemoral or central DVT after single-session treatment with a novel mechanical aspiration thrombectomy device as an alternative to initiation of CDT.

METHODS

This was a single-center retrospective review of patients with acute iliofemoral or central DVT treated with the Indigo continuous aspiration mechanical thrombectomy 8 system (Penumbra, Inc, Alameda, Calif) from 2016 to 2017. The primary outcome was technical success, defined as resolution of >70% of thrombus without need for postaspiration CDT, as an initial or adjunctive treatment. Secondary end points included DVT recurrence and treatment complications.

RESULTS

There were 10 patients (50% male) with a median age of 44 years (range, 19-68 years). Indication for treatment was DVT (n = 4), recurrent DVT (n = 1), stent thrombosis (n = 3), high-grade extrinsic narrowing of the inferior vena cava (IVC) due to immunoglobulin G4-related disease (n = 1), and IVC obstruction from liver tumor invasion (n = 1). Five patients had underlying May-Thurner syndrome. Five patients had iliofemoral involvement, two iliocaval, and one iliac vein alone. Two patients had central DVT, one of them involving the IVC and one involving the superior vena cava with brachiocephalic extension. Aspiration thrombectomy was technically successful in a total of six patients. Success was achieved in five of eight patients as the initial or main treatment modality and as an adjunctive treatment in one of two patients. Of the four patients in whom aspiration thrombectomy was not successful, three underwent successful further treatment with CDT. Recurrence after successful aspiration was seen in two patients. One patient developed pulmonary embolism that required no additional treatment. One patient experienced severe headaches treated with oral analgesics.

CONCLUSIONS

We observed a technical success of 60% for acute iliofemoral and central DVT with an aspiration thrombectomy system that allowed definitive treatment in one setting. As a novel therapy, this avoided the need for thrombolysis in the majority of selected cases with no bleeding complications and is a promising technique for acute DVT management.

Pulmonary Embolism Response Teams: A Novel Approach for the Care of Complex Patients With Pulmonary Embolism

Pulmonary embolism represents the third most common cause of cardiovascular death in the United States. Reperfusion therapeutic strategies such as systemic thrombolysis, catheter directed therapies, surgical pulmonary embolectomy, and cardiopulmonary support devices are currently available for patients with high- and intermediate-high–risk pulmonary embolism. However, deciding on optimal therapy may be challenging. Pulmonary embolism response teams have been designed to facilitate multidisciplinary decision-making with the goal to improve quality of care for complex cases with pulmonary embolism. Herein, we discuss the current role and strategies on how to leverage the strengths from pulmonary embolism response teams, its possible worldwide adoption, and implementation to improve survival and change the paradigm in the care of a potentially deadly disease.

In vitro study for the evaluation of transluminal aspiration as a novel treatment option for thrombosis in the HeartWare HVAD

INTRODUCTION:

Pump thrombosis of left ventricular assist devices remains a devastating complication with high morbidity and mortality. Despite the improvements made, the matter affects many patients and the treatment options are limited to thrombolysis and surgical replacement. An alternative approach using the aspiration Indigo catheter was tested.

METHODS:

An Indigo thrombectomy catheter was used within an in vitro model to assess the direct aspiration of prefabricated clots from three different positions within the HeartWare HVAD (inlet, outlet, and housing). The experiments were conducted with a straight and an angled catheter. The aspiration pressure was constant. The flow, power consumption, and pressure head of the left ventricular assist devices were measured at pre-defined measuring points.

RESULTS:

The device was more effective (success rate 71%) at inlet and outlet of the left ventricular assist device. In addition, the duration of aspiration and the aspiration volume were shorter in comparison to the aspiration in the housing (inlet M = 19.75 s, outlet M = 60.50 s, and housing M = 38.75 s). Moreover, the aspiration volume was associated with the aspiration duration and the weight of thrombi but not with their volume. Noteworthy, the angled catheter showed an improved performance compared to the straight one (67%-33%). The recorded parameters showed no major changes during the use of the catheter. After application of the Indigo catheter, flow and pressure head of the pump could be restored.

CONCLUSIONS:

The aspiration system showed promising results under specific conditions for the treatment of pump thrombosis in an in vitro model. However, further examination, including in vivo experiments, will justify its effectiveness.