Ultrasound-facilitated, catheter-directed thrombolysis vs anticoagulation alone for acute intermediate-high-risk pulmonary embolism: Rationale and design of the HI-PEITHO study

When should we involve interventional radiology in the management of acute pulmonary embolism?

Pulmonary embolism (PE) is a common disease associated with high morbidity and mortality. Currently, guidelines recommend systemic thrombolysis in patients with haemodynamic instability (high-risk PE) or patients with intermediate-high-risk PE with haemodynamic deterioration. Nevertheless, more than half of high-risk PE patients do not receive systemic thrombolysis due to a perceived increased risk of bleeding. In these cases, percutaneous catheter-directed therapy (CDT) or surgical embolectomy should be considered. CDT has emerged and appears to be an effective alternative in treating PE, with a hypothetical lower risk of bleeding than systemic thrombolysis, acting directly in the thrombus with a much lower dose of thrombolytic drug or even without thrombolytic therapy. CDT techniques include catheter-directed clot aspiration or fragmentation, mechanical embolectomy, local thrombolysis, and combined pharmaco-mechanical approaches. A few observational prospective studies have demonstrated that CDT improves right ventricular function with a low rate of haemorrhage. Nevertheless, the evidence from randomised controlled trials is scarce. Here we review different scenarios where CDT may be useful and trials ongoing in this field. These results may change the upcoming guidelines for management and treatment of PE, establishing CDT as a recommended treatment in patients with acute intermediate-high-risk PE.

Indigo® Aspiration System for thrombectomy in pulmonary embolism

Anticoagulation is mainstay therapy for patients with acute pulmonary embolism while systemic thrombolysis is reserved for those with hemodynamic instability. Over the last decade, percutaneous interventional options have entered the landscape aimed to achieve rapid pharmacomechanical pulmonary artery recanalization. The Penumbra Indigo® Aspiration System (Penumbra Inc., CA, USA) is a US FDA-approved large-bore aspiration thrombectomy device for the treatment of pulmonary embolism. Recent data has demonstrated improved radiographic end points with low rates of major adverse events in cases of intermediate-risk pulmonary embolism. In this review article, we outline device technology, applications, evidence and future directions.

Prediction of in-hospital deterioration in normotensive pulmonary embolism remains elusive: external validation of the calgary acute pulmonary embolism score

Acute pulmonary embolism (PE) is a frequently diagnosed condition. Prediction of in-hospital deterioration is challenging with current risk models. The Calgary Acute Pulmonary Embolism (CAPE) score was recently derived to predict in-hospital adverse PE outcomes but has not yet been externally validated. Retrospective cohort study of normotensive acute pulmonary embolism cases diagnosed in our emergency department between 2017 and 2019. An external validation of the CAPE score was performed in this population for prediction of in-hospital adverse outcomes and a secondary outcome of 30-day all-cause mortality. Performance of the simplified Pulmonary Embolism Severity Index (sPESI) and Bova score was also evaluated. 712 patients met inclusion and exclusion criteria, with 536 patients having a sPESI score of 1 or more. Among this population, the CAPE score had a weak discriminative power to predict in-hospital adverse outcomes, with a calculated c-statistic of 0.57. In this study population, an external validation study found weak discriminative power of the CAPE score to predict in-hospital adverse outcomes among normotensive PE patients. Further efforts are needed to define risk assessment models that can identify normotensive PE patients at risk for in hospital deterioration. Identification of such patients will better guide intensive care utilization and invasive procedural management of PE.

Novel Risk Stratification and Hemodynamic Profiling in Acute Pulmonary Embolism: A Proposed Classification Inspired by Society for Cardiovascular Angiography and Intervention Shock Staging

Treatment options for patients with acute pulmonary embolism (PE) and right ventricular shock (RVS) have grown exponentially. Therapy options include anticoagulation, systemic thrombolysis, catheter-based thrombolysis/ thrombectomy, and may include short-term mechanical circulatory support. However, the incidence of short-term morbidity and mortality has not changed despite the emergence of several advanced therapies in acute PE. This is possibly due to the inclusion of heterogenous populations in research studies without differentiation based on the acuity/severity of presentation. We propose a novel classification for PE-RVS to allow for standardizing appropriate therapy escalation and better communication of the severity among cardiovascular critical care, and emergency health care professionals.

[Thromboembolic diseases from a cardiological point of view]

Thromboembolic disease is associated with a high mortality. It can be divided into two groups: embolism from a venous and embolism from an arterial side. This article gives an overview on thromboembolic disease (with a focus on pulmonary embolism and ischemic stroke) from a cardiologist's perspective.The therapeutic options for acute pulmonary embolism range from anticoagulation to fibrinolysis to interventional recanalization and surgery. The deciding factor for choice of therapy is the risk of early death. Besides clinical parameters, laboratory markers like cardiac troponin and right ventricular function on echocardiography or CTPA (computed tomography pulmonary angiography) are used to determine the early mortality risk. In hemodynamically instable patients, immediate thrombolysis is required, whereas patients with intermediate and low risk can be treated with anticoagulation. Interventional recanalization is currently being studied in patients at risk for development of CTEPH (chronic thromboembolic pulmonary hypertension) or an intermediate risk of early mortality.In ischemic stroke, early interdisciplinary workup involving a cardiologist is paramount. Post stroke screening should include monitoring for arrythmias (especially atrial fibrillation) and transthoracic echocardiography as well as sonography of extra- and intracranial arteries. If no embolic source can be detected (embolic stroke of undetermined source), transesophageal echo can be helpful to detect intracardiac shunts like patent foramen ovale (PFO) or intracardiac tumors. Post stroke care includes secondary prevention measures like risk factor modification and lipid lowering therapy as well as anticoagulation. In high risk for paradoxical embolization, interventional PFO closure can be performed. Interventional closure of the left atrial appendage (LAA) can be discussed in patients with both high thromboembolic and bleeding risk.

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.

Amoeba-Inspired Magnetic Venom Microrobots

Nature provides a successful evolutionary direction for single-celled organisms to solve complex problems and complete survival tasks - pseudopodium. Amoeba, a unicellular protozoan, can produce temporary pseudopods in any direction by controlling the directional flow of protoplasm to perform important life activities such as environmental sensing, motility, predation, and excretion. However, creating robotic systems with pseudopodia to emulate environmental adaptability and tasking capabilities of natural amoeba or amoeboid cells remains challenging. Here, this work presents a strategy that uses alternating magnetic fields to reconfigure magnetic droplet into Amoeba-like microrobot, and the mechanisms of pseudopodia generation and locomotion are analyzed. By simply adjusting the field direction, microrobots switch in monopodia, bipodia, and locomotion modes, performing all pseudopod operations such as active contraction, extension, bending, and amoeboid movement. The pseudopodia endow droplet robots with excellent maneuverability to adapt to environmental variations, including spanning 3D terrains and swimming in bulk liquids. Inspired by the "Venom," the phagocytosis and parasitic behaviors have also been investigated. Parasitic droplets inherit all the capabilities of amoeboid robot, expanding their applicable scenarios such as reagent analysis, microchemical reactions, calculi removal, and drug-mediated thrombolysis. This microrobot may provide fundamental understanding of single-celled livings, and potential applications in biotechnology and biomedicine.

Mortality and bleeding associated with the management of sub-massive pulmonary embolism: a systematic review and Bayesian network meta-analysis

Current guidelines recommend anticoagulation (AC) for low and intermediate-risk pulmonary embolism (PE) and systemic thrombolysis (tPA) for high risk (massive) PE. How these treatment options compare with other modalities of treatment such as catheter directed thrombolysis (CDT), ultrasound assisted catheter thrombolysis (USAT), and administering lower dose of thrombolytics (LDT) is unclear. There is no study that has compared all these treatment options. We conducted a systematic review and Bayesian network meta-analysis of randomized controlled trials in patients with submassive (intermediate risk) PE. Fourteen randomized controlled trials were included, comprising 2132 patients. On Bayesian network meta-analysis, a significant decrease in mortality was noted in tPA versus AC. There was no significant difference between USAT versus CDT. For risk of major bleeding, there was no significant difference in relative risk of major bleeding between tPA versus AC and USAT versus CDT. tPA was found to have a significantly higher risk of minor bleeding and a lower risk of recurrent PE compared to AC. Systemic thrombolysis is associated with a significant reduction in mortality and recurrent PE compared to anticoagulation but an increased risk of minor bleeding. There was no difference in risk of major bleeding. Our study also shows that while the newer modalities of treatment for pulmonary embolism are promising, there is lack of data to comment on the purported advantages.

Clinical controversies in the management of acute pulmonary embolism: evaluation of four important but controversial aspects of acute pulmonary embolism management that are still subject of debate and research

INTRODUCTION

Acute pulmonary embolism (PE) is a disease with a broad spectrum of clinical presentations. While some patients can be treated at home or may even be left untreated, other patients require an aggressive approach with reperfusion treatment.

AREAS COVERED

(1) Advanced reperfusion treatment in hemodynamically stable acute PE patients considered to be at high risk of decompensation and death, (2) the treatment of subsegmental pulmonary embolism, (3) outpatient treatment for hemodynamically stable PE patients with signs of right ventricle (RV) dysfunction, and (4) the optimal approach to identify and treatpost-PE syndrome.

EXPERT OPINION

Outside clinical trials, hemodynamically stable acute PE patients should not be treated with primary reperfusion therapy. Thrombolysis and/or catheter-directed therapy are only to be considered as rescue treatment. Subsegmental PE can be left untreated in selected low-risk patients, after proximal deep vein thrombosis has been ruled out. Patients with an sPESI or Hestia score of 0 criteria can be treated at home, independent of the presence of RV overload. Finally, health-care providers should be aware of post-PE syndrome and diagnose chronic thromboembolic pulmonary disease (CTEPD) as early as possible. Persistently symptomatic patients without CTEPD benefit from exercise training and cardiopulmonary rehabilitation.

Long term recovery of right ventricular function after treatment of intermediate and high risk pulmonary emboli

INTRODUCTION

Pulmonary embolism (PE) is a common and significant source of mortality and morbidity worldwide. A subset of patients with PE, particularly those who have intermediate and high risk events, are at increased risk for long-term right ventricular (RV) dysfunction; however, the impact of novel advanced therapies used for acute PE, including catheter-directed intervention, on long-term RV function remains uncertain. We sought to determine whether use of advanced therapies (catheter-directed intervention or systemic thrombolysis) is associated with improved long-term RV function.

MATERIALS AND METHODS

Retrospective, single-center cohort study of adult (≥18 year old) patients admitted and discharged alive with a diagnosis of acute PE, who fell under the category of intermediate or high risk, with available follow-up echocardiograms at least 6 months after the index, seen at a single quaternary referral center in Los Angeles, CA between 2012 and 2021.

RESULTS

There were 113 patients in this study (58 (51.3 %) treated with anticoagulation alone, 12 (10.6 %) treated with systemic thrombolysis, and 43 (38.1 %) treated with catheter-directed intervention), with approximately equal gender and racial distribution. Patients treated with advanced therapies were significantly more likely to have moderate-severe RV dysfunction (100 % for those treated with thrombolysis, 88.3 % for those treated with catheter-directed intervention, vs 55.2 % for those treated with anticoagulation alone; p < 0.001). At a follow-up of about 1.5 years, patients treated with advanced therapy (systemic thrombolysis or catheter-directed intervention) were more likely to have normalization of RV function (93-100 % vs 81 % for anticoagulation alone, p = 0.04). The subgroup of patients with intermediate-risk PE was significantly more likely to have normalization of RV function (95.6 % vs 80.4 % for anticoagulation alone, p = 0.03). Use of advanced therapy was not associated with substantial short-term adverse events among patients who survived to hospital discharge.

CONCLUSION

Patients with intermediate and high risk PE were more likely to have recovery in RV function long-term if treated with catheter-directed intervention or systemic thrombolysis, as compared to anticoagulation alone, without substantial safety issues, despite having worse RV function at baseline. Further data is needed to verify this observation.

Clinical outcomes of ultrasound-assisted, coagulation monitoring-adjusted catheter-directed thrombolysis for acute pulmonary embolism

BACKGROUND

Ultrasound-assisted catheter-directed thrombolysis (USAT) may reverse right ventricular dysfunction due to acute pulmonary embolism (PE) with a favorable safety profile.

METHODS

We studied intermediate-high- and high-risk acute PE patients who underwent USAT at the University Hospital Zurich, 2018-2022. The USAT regimen included alteplase 10 mg per catheter over 15 h, therapeutic-dosed heparin, and dosage adaptations based on routinely monitored coagulation parameters, notably anti-factor Xa activity and fibrinogen. We focused on the mean pulmonary arterial pressure (mPAP) and the National Early Warning Score (NEWS) before and after USAT, and reported the incidence of hemodynamic decompensation, PE recurrence, major bleeding, and death over 30 days.

RESULTS

We included 161 patients: 96 (59.6 %) were men and the mean age was 67.8 (SD 14.6) years. Mean PAP decreased from a mean of 35.6 (SD 9.8) to 25.6 (SD 8.2) mmHg, whereas the NEWS decreased from a median of 5 (Q1-Q3 4-6) to 3 (Q1-Q3 2-4) points. No cases of hemodynamic decompensation occurred. One (0.6 %) patient had an episode of recurrent PE. Two (1.2 %) major bleeding events occurred, including one (0.6 %) intracranial, fatal hemorrhage in a patient with high-risk PE, severe heparin overdosing, and a recent head trauma (with negative CT scan of the brain performed at baseline). No other deaths occurred.

CONCLUSIONS

USAT resulted in a rapid improvement of hemodynamic parameters among patients with intermediate-high risk acute PE and selected ones with high-risk acute PE, without any recorded deaths related to PE itself. A strategy including USAT, therapeutic-dosed heparin, and routinely monitored coagulation parameters may partly explain the overall very low rate of major bleeding.

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.

The many roles of urgent catheter interventions: from myocardial infarction to acute stroke and pulmonary embolism

INTRODUCTION

Cardiovascular diseases (CVDs) are the leading cause of cardiovascular mortality and a major contributor to disability worldwide. The prevalence of CVDs is continuously increasing, and from 1990 to 2019, it has doubled. Global cardiovascular mortality has increased from 12.1 million in 1990 to 18.6 million cases in 2019. The development of therapeutic options for these diseases is at the forefront of interest concerning the extensive socio-economic consequences. Modern endovascular transcatheter therapeutic options contribute to the reduction of cardiovascular morbidity and mortality.

AREAS COVERED

The article concentrates on the triad of the most common causes of acute cardiovascular mortality and morbidity - myocardial infarction, ischemic stroke, and pulmonary embolism. Current evidence-based indications, specific interventional techniques, and remaining unsolved issues are reviewed and compared. A personal perspective on the possible implications for the future is provided.

EXPERT OPINION

Primary angioplasty for ST-segment elevation myocardial infarction is a well-established therapeutic option with proven mortality benefits. We suppose that catheter-based interventions for acute stroke will spread quickly from centers of excellence to routine clinical practice. We believe that ongoing research will provide a basis for the expansion of interventional treatment of pulmonary embolism soon.

Risk stratification and risk-adapted management of acute pulmonary embolism

Pulmonary embolism is one of the leading causes of cardiovascular death in Europe. Rapid diagnosis and treatment initiation are essential, especially in hemodynamically unstable patients. For normotensive patients, the diagnostic workflow is based on the clinical probability of pulmonary embolism. Due to numerous differential diagnoses and a highly variable clinical presentation, diagnosis of acute pulmonary embolism still remains a clinical challenge. Computed tomography angiography is the common gold standard to confirm pulmonary embolism and bedside echocardiography adds a major impact in clinical decision making. The European Society of Cardiology guidelines serve as a framework for a standardized diagnostic approach and risk prediction. Based on vital signs, clinical scores, biomarkers and imaging results, four risk categories can be defined and treatment is accordingly. To optimize the individual management of critical patients, multidisciplinary pulmonary embolism response teams are increasingly designated in specialized centers. This article provides an overview of the current risk-adapted management of patients with acute pulmonary embolism.

Catheter-Directed Thrombolysis vs Anticoagulation in Patients With Acute Intermediate-High-risk Pulmonary Embolism: The CANARY Randomized Clinical Trial

Importance

The optimal treatment of intermediate-high-risk pulmonary embolism (PE) remains unknown.

Objective

To assess the effect of conventional catheter-directed thrombolysis (cCDT) plus anticoagulation vs anticoagulation monotherapy in improving echocardiographic measures of right ventricle (RV) to left ventricle (LV) ratio in acute intermediate-high-risk PE.

Design, Setting, and Participants

The Catheter-Directed Thrombolysis vs Anticoagulation in Patients with Acute Intermediate-High-Risk Pulmonary Embolism (CANARY) trial was an open-label, randomized clinical trial of patients with intermediate-high-risk PE, conducted in 2 large cardiovascular centers in Tehran, Iran, between December 22, 2018, through February 2, 2020.

Interventions

Patients were randomly assigned to cCDT (alteplase, 0.5 mg/catheter/h for 24 hours) plus heparin vs anticoagulation monotherapy.

Main Outcomes and Measures

The proportion of patients with a 3-month echocardiographic RV/LV ratio greater than 0.9, assessed by a core laboratory, was the primary outcome. The proportion of patients with an RV/LV ratio greater than 0.9 at 72 hours after randomization and the 3-month all-cause mortality were among secondary outcomes. Major bleeding (Bleeding Academic Research Consortium type 3 or 5) was the main safety outcome. A clinical events committee, masked to the treatment assignment, adjudicated clinical outcomes.

Results

The study was prematurely stopped due to the COVID-19 pandemic after recruiting 94 patients (mean [SD] age, 58.4 [2.5] years; 27 women [29%]), of whom 85 patients completed the 3-month echocardiographic follow-up. Overall, 2 of 46 patients (4.3%) in the cCDT group and 5 of 39 patients (12.8%) in the anticoagulation monotherapy group met the primary outcome (odds ratio [OR], 0.31; 95% CI, 0.06-1.69; P = .24). The median (IQR) 3-month RV/LV ratio was significantly lower with cCDT (0.7 [0.6-0.7]) than with anticoagulation (0.8 [0.7-0.9); P = .01). An RV/LV ratio greater than 0.9 at 72 hours after randomization was observed in fewer patients treated with cCDT (13 of 48 [27.0%]) than anticoagulation (24 of 46 [52.1%]; OR, 0.34; 95% CI, 0.14-0.80; P = .01). Fewer patients assigned to cCDT experienced a 3-month composite of death or RV/LV greater than 0.9 (2 of 48 [4.3%] vs 8 of 46 [17.3%]; OR, 0.20; 95% CI, 0.04-1.03; P = .048). One case of nonfatal major gastrointestinal bleeding occurred in the cCDT group.

Conclusions and Relevance

This prematurely terminated randomized clinical trial of patients with intermediate-high-risk PE was hypothesis-generating for improvement in some efficacy outcomes and acceptable rate of major bleeding for cCDT compared with anticoagulation monotherapy and provided support for a definitive clinical outcomes trial.

Trial Registration

ClinicalTrials.gov Identifier: NCT05172115.

Pulmonary Embolism Response Teams: Theory, Implementation, and Unanswered Questions

Pulmonary embolism (PE) continues to represent a significant health care burden and its incidence is steadily increasing worldwide. Constantly evolving therapeutic options and the rarity of randomized controlled trial data to drive clinical guidelines impose challenges on physicians caring for patients with PE. Recently, PE response teams have been developed and recommended to help address these issues by facilitating a consensus among local experts while advocating the management of acute PE according to each individual patient profile. In this review, we focus on the clinical challenges supporting the need for a PE response team, report the current evidence for their implementation, assess their impact on PE management and outcomes, and address unanswered questions and future directions.

An Update on the Management of Acute High-Risk Pulmonary Embolism

Hemodynamic instability and right ventricular (RV) dysfunction are the key determinants of short-term prognosis in patients with acute pulmonary embolism (PE). High-risk PE encompasses a wide spectrum of clinical situations from sustained hypotension to cardiac arrest. Early recognition and treatment tailored to each individual are crucial. Systemic fibrinolysis is the first-line pulmonary reperfusion therapy to rapidly reverse RV overload and hemodynamic collapse, at the cost of a significant rate of bleeding. Catheter-directed pharmacological and mechanical techniques ensure swift recovery of echocardiographic parameters and may possess a better safety profile than systemic thrombolysis. Further clinical studies are mandatory to clarify which pulmonary reperfusion strategy may improve early clinical outcomes and fill existing gaps in the evidence.

Fixed-Dose Ultrasound-Assisted Catheter-Directed Thrombolysis for Acute Pulmonary Embolism Associated with COVID-19

Background. Fixed-dose ultrasound-assisted catheter-directed thrombolysis (USAT) rapidly improves hemodynamic parameters and reverses right ventricular dysfunction caused by acute pulmonary embolism (PE). The effectiveness of USAT for acute PE associated with coronavirus disease 2019 (COVID-19) is unknown. Methods and results. The study population of this cohort study consisted of 36 patients with an intermediate-high- or high-risk acute PE treated with a fixed low-dose USAT protocol (r-tPA 10–20 mg/15 h). Of these, 9 patients tested positive for COVID-19 and were age–sex-matched to 27 patients without COVID-19. The USAT protocol included, beyond the infusion of recombinant tissue plasminogen activator, anti-Xa-activity-adjusted unfractionated heparin therapy (target 0.3–0.7 U/mL). The study outcomes were the invasively measured mean pulmonary arterial pressure (mPAP) before and at completion of USAT, and the National Early Warning Score (NEWS), according to which more points indicate more severe hemodynamic impairment. Twenty-four (66.7%) patients were men; the mean age was 67 ± 14 years. Mean ± standard deviation mPAP decreased from 32.3 ± 8.3 to 22.4 ± 7.0 mmHg among COVID-19 patients and from 35.4 ± 9.7 to 24.6 ± 7.0 mmHg among unexposed, with no difference in the relative improvement between groups (p = 0.84). Within 12 h of USAT start, the median NEWS decreased from six (Q1–Q3: 4–8) to three (Q1–Q3: 2–4) points among COVID-19 patients and from four (Q1–Q3: 2–6) to two (Q1–Q3: 2–3) points among unexposed (p = 0.29). One COVID-19 patient died due to COVID-19-related complications 14 days after acute PE. No major bleeding events occurred. Conclusions. Among patients with COVID-19-associated acute PE, mPAP rapidly decreased during USAT with a concomitant progressive improvement of the NEWS. The magnitude of mPAP reduction was similar in patients with and without COVID-19.