Intermediate-Risk and High-Risk Pulmonary Embolism: Recognition and Management: Cardiology Clinics: Cardiac Emergencies

Pulmonary embolism (PE) is the third most common cause of cardiovascular death. Every specialty of medical practitioner will encounter PE in their patients, and should be prepared to employ contemporary strategies for diagnosis and initial risk-stratification. Treatment of PE is based on risk-stratification, with anticoagulation for all patients, and advanced modalities including systemic thrombolysis, catheter-directed therapies, and mechanical circulatory supports utilized in a manner paralleling PE severity and clinical context.

Paradoxical pulmonary artery systolic pressure response with catheter-directed therapies for pulmonary embolism

Background

Early data on use of catheter-directed therapies (CDT) for treatment of Intermediate or High-Risk pulmonary embolism (PE) show improvement in pulmonary artery systolic pressures (PAsP) and RV/LV ratios. Occasionally a paradoxical rise in PAsP was observed with CDT utilizing ultrasound-assisted thrombolysis (USAT). It is unclear whether this pattern is seen with CDT utilizing mechanical aspiration.

Objectives

To investigate and compare the changes in PAsP between those who underwent CDT with USAT to those with mechanical aspiration.

Methods

A retrospective analysis of those diagnosed with Intermediate or High-Risk PE who underwent CDT using USAT or mechanical aspiration from 7/2013 to 3/2023. The primary outcome was comparison of PAsP changes between the two modalities. Secondary outcomes include length of stay, mortality, and bleeding complications.

Results

A total of 142 patients were analyzed, of which 93 underwent USAT and 49 underwent mechanical thrombectomy. The mechanical thrombectomy group had significantly lower post-intervention PAsP than the USAT group (42.2 ± 13.4 mmHg vs 54.5 ± 15.2 mmHg, p < 0.0001) and a greater adjusted mean reduction (-16.5 ± 2.7 vs. -7.7 ± 3.2 mmHg. p < 0.0001). A higher frequency of a paradoxical rise in PAsP was observed in the USAT group (22 % vs 4.1 %, p < 0.001).

Conclusions

CDT utilizing mechanical thrombectomy was associated with lower post-interventional PAsP and greater mean negative change compared to USAT. Occasional paradoxical rises in PAsP were observed with both types of CDT, but they were more frequent with USAT. Hemodynamic monitoring should be considered after CDT.

Condensed unstructured abstract

We report a retrospective comparison of changes to pulmonary artery systolic pressures (PAsPs) between catheter-directed ultrasound-assisted thrombolysis (USAT) and catheter-directed mechanical thrombectomy in Intermediate and High-Risk pulmonary embolism. Those treated with mechanical thrombectomy compared to USAT had significantly lower post-interventional PAsP (42.2 ± 13.4 mmHg vs 54.5 ± 15.2 mmHg, p < 0.0001) and a greater adjusted mean reduction (-16.2 ± 2.7 vs. -7.5 ± 3.2 mmHg, p < 0.0001). A paradoxical rise in PAsP was observed more frequently in the USAT group than the mechanical thrombectomy group (22 % vs 4.1 %, p < 0.001).

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.

Improved long-term outcomes with catheter-directed therapies over medical management in patients with submassive pulmonary embolism-a retrospective matched cohort study

BACKGROUND

The benefit of catheter-directed therapy (CDT) for submassive pulmonary embolism (sPE) has been the subject of debate. We sought to determine the short- and long-term mortality and outcomes of CDT compared with anticoagulation for patients with sPE.

METHODS

We performed a single healthcare network, multihospital, retrospective cohort study of hospitalizations for sPE from 2012 to 2019. sPE was defined as the presence of right heart strain or elevated biomarkers (troponin I or B-type natriuretic peptide). Patients with massive PE and those who had undergone systemic thrombolysis were excluded. The sPE groups included therapeutic anticoagulation alone or anticoagulation plus CDT (ie, thrombolysis or suction thrombectomy). The primary outcome was mortality at 1, 3, and 5 years. The other measured outcomes included PE-related death, short term mortality (30 days and 3 and 6 months), 30-day treatment-related complications (eg, bleeding, transfusion, stroke), chronic thromboembolic pulmonary hypertension, and 6-minute walk test at 1 year. After 1:1 nearest-neighbor propensity score matching, Kaplan-Meier survival plots were generated, and the treatment groups were compared using log-rank testing. We used Cox multivariate analysis to evaluate the outcomes after clustering at the hospital level, generating matched hazard ratios (mHRs) with associated 95% confidence intervals (CIs).

RESULTS

Of 6746 sPE hospitalizations, the patients who had received CDT were younger (age, 58.9 ± 15.5 years vs 61.5 ± 17.4 years; P = .004), were more frequently White (92.5% vs 85.7%; P < .001), and had presented with a higher mean heart rate (104.6 bpm vs 94.9 bpm; P < .001), lower median systolic blood pressure (129 mm Hg vs 135 mm Hg; P < .001), and a greater incidence of right heart strain (79.2% vs 20.3%; P < .001). A total of 470 patients were matched, with 235 in the CDT group and 235 in the anticoagulation-only group. CDT was associated with a lower risk of mortality compared with anticoagulation at 1 year (7.6% vs 9.8%; mHR, 0.77; 95% CI, 0.65-0.92; P = .004), 3 years (11.1% vs 16.6%; mHR, 0.64; 95% CI, 0.55-0.73; P < .001), and 5 years (14.5% vs 19.1%; mHR, 0.71; 95% CI, 0.66-0.77; P < .001). Anticoagulation alone resulted in a greater incidence of PE-related deaths at 1, 3, and 5 years. The mortality at 30 days and 3 months was similar; however, CDT had resulted in better survival at 6 months (mHR, 0.81; 95% CI, 0.68-0.97; P = .02). No differences were found between the two groups in the incidence of bleeding complications at 30 days, development of chronic thromboembolic pulmonary hypertension, or the mean walking distance at 1 year.

CONCLUSIONS

CDT plus anticoagulation for sPE was associated with improved long-term survival compared with anticoagulation alone, with a lower incidence of PE-related death and a low complication rate. CDT should be considered for select patients with sPE given its survival benefit.

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

Background

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

Results

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

Conclusions

Catheter directed HMD for high-risk and intermediate-high-risk PE is safe and effective with acceptable mortality

Trial registration Clinical trial ID: NCT04099186.

Reperfusion therapies in pulmonary embolism-state of the art and expert opinion: A position paper from the "Unité de Soins Intensifs de Cardiologie" group of the French Society of Cardiology

Acute pulmonary embolism is a frequent cardiovascular emergency with an increasing incidence. The prognosis of patients with high-risk and intermediate-high-risk pulmonary embolism has not improved over the last decade. The current treatment strategies are mainly based on anticoagulation to prevent recurrence and reduce pulmonary vasculature obstruction. However, the slow rate of thrombus lysis under anticoagulation is unable to acutely decrease right ventricle overload and pulmonary vasculature resistance in patients with severe obstruction and right ventricle dysfunction. Therefore, patients with high-risk and intermediate-high-risk pulmonary embolism remain a therapeutic challenge. Reperfusion therapies may be discussed for these patients, and include systemic thrombolysis, catheter-directed therapies and surgical thrombectomy. High-risk patients require systemic thrombolysis, but may have contraindications as a result of the high risk of bleeding. In addition, intermediate-high-risk patients should not receive systemic thrombolysis, despite its high efficacy, because of prohibitive bleeding complications. Recently, percutaneous reperfusion techniques have been developed to acutely decrease pulmonary vascular obstruction with lower-dose or no thrombolytic agents and, thus, potentially higher safety than systemic thrombolysis. Some of these techniques improve key haemodynamic variables. Cardiac surgical techniques and venoarterial extracorporeal membrane oxygenation as temporary circulatory support may be useful in selected cases. The development of pulmonary embolism centres with multidisciplinary pulmonary embolism teams is mandatory to enable adequate use of reperfusion and improve outcomes. We aim to present the state of the art regarding reperfusion therapies in pulmonary embolism, but also to provide guidance on their indications and patient selection.

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.

Overview of Management of Intermediate- and High-Risk Pulmonary Embolism

Anticoagulation is the cornerstone of acute pulmonary embolism (PE) therapy. Intermediate-risk (submassive) or high-risk (massive) PE patients have higher mortality than low-risk patients. It is generally accepted that high-risk PE patients should be considered for more aggressive therapy. Intermediate-risk patients can be subdivided, although more than simply categorizing the patient is required to guide therapy. Therapeutic approaches depend on a prompt, detailed evaluation, and PE response teams may help with rapid assessment and initiation of therapy. More clinical trial data are needed to guide clinicians in the management of acute intermediate- and high-risk PE patients.

ACR Appropriateness Criteria® Radiologic Management of Iliofemoral Venous Thrombosis

Iliofemoral venous thrombosis carries a high risk for pulmonary embolism, recurrent deep vein thrombosis, and post-thrombotic syndrome complicating 30% to 71% of those affected. The clinical scenarios in which iliofemoral venous thrombosis is managed may be diverse, presenting a challenge to identify optimum therapy tailored to each situation. Goals for management include preventing morbidity from venous occlusive disease, and morbidity and mortality from pulmonary embolism. Anticoagulation remains the standard of care for iliofemoral venous thrombosis, although a role for more aggressive therapies with catheter-based interventions or surgery exists in select circumstances. Results from recent prospective trials have improved patient selection guidelines for more aggressive therapies, and have also demonstrated a lack of efficacy for certain conservative therapies. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Catheter-directed therapy for acute pulmonary embolism: navigating gaps in the evidence

Systemic thrombolysis for acute pulmonary embolism (PE) reduces the risk of death and cardiovascular collapse but is associated with an increased rate of bleeding. The desire to minimize the risk of bleeding events has driven the development of catheter-based strategies for pulmonary reperfusion in PE. These catheter-based strategies utilize lower-dose fibrinolytic regimens or purely mechanical techniques to expedite removal of the embolus. Several devices providing mechanical or suction embolectomy and catheter-directed thrombolysis, with or without facilitation by ultrasound, have been tested. Data are inconsistent regarding the efficacy and safety of mechanical and suction embolectomy. The most comprehensive data on catheter-based techniques stem from trials of ultrasound-facilitated catheter fibrinolysis. Ultrasound-facilitated catheter fibrinolysis relieves right ventricular pressure overload with a lower risk of major bleeding and intracranial haemorrhage than historical rates with systemic fibrinolysis. However, further research is required to determine the optimal application of ultrasound-facilitated catheter fibrinolysis and other catheter-based therapies in patients with acute PE.

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.

Catheter-Based Embolectomy for Acute Pulmonary Embolism: Devices, Technical Considerations, Risks, and Benefits

A significant number of patients with high-risk pulmonary embolism have contraindications to thrombolytic therapy. Catheter-based therapy may be helpful and consists of a multitude of catheters and techniques, some old and some new. Although there are few data supporting the use of any of these techniques, there has been a recent rise in interest and use of catheter-based pulmonary embolectomy. This text describes the contemporary devices used in pulmonary embolism treatment, discusses their challenges, and proposes some future directions.

Catheter-Directed Therapy for Pulmonary Embolism: Patient Selection and Technical Considerations

Acute pulmonary embolism (PE) is the third most common cause of death among hospitalized patients. Treatment escalation beyond anticoagulation therapy is necessary in patients with cardiogenic shock and may be of benefit in select normotensive patients with right heart strain. Percutaneous catheter-based techniques (catheter-directed mechanical thrombectomy, clot maceration, and/or pharmacologic thrombolysis) as an alternative or adjunct to systemic thrombolysis can rapidly debulk central clot in patients with shock. Catheter-directed thrombolysis, which uses a low-dose intraclot prolonged thrombolytic infusion, is a promising but insufficiently studied therapy for patients presenting with acute intermediate-risk PE.

Catheter-directed therapy as a treatment for submassive pulmonary embolism: A meta-analysis

AIMS

Catheter-directed therapy (CDT) is included in the guidelines for diagnosing and treating massive pulmonary embolism. However, few studies have evaluated the efficacy of CDT as a treatment for submassive pulmonary embolism (SPE). Therefore, we used evidence-based medicine to evaluate the effectiveness and safety of CDT in treating SPE.

METHODS

Search terms describing CDT in SPE and patients with intermediate pulmonary embolism were entered into the PubMed, Embase and Cochrane Library databases to identify relevant articles without language restrictions published between January 1990 and December 2016. A quality assessment and data extraction were performed by two investigators. The clinical efficacy of and major complications associated with treatment were analysed using a fixed effects model.

KEY FINDINGS

A total of 552 patients in 16 studies were included in this meta-analysis. The clinical success rate in CDT was approximately 100% (95% confidence interval (CI): 99%, 100%), the primary bleeding rate was 0.02% (95% CI: 0%, 0.05%), and mortality during hospitalization was approximately 0% (95% CI: 0%, 0.01%). The mean decrease in pulmonary artery systolic pressure after treatment was -14.9% (95% CI: -19.25%, -10.55%), and the mean post-treatment change in the ratio of the right to the left ventricle (RV/LV) was -0.35% (95% CI: -0.48%, -0.22%).

SIGNIFICANCE

CDT is effective and safe as a treatment for SPE and could be a first-line treatment for SPE under specific conditions.

Guided longer pulses from a diagnostic ultrasound and intraclot microbubble enhanced catheter-directed thrombolysis in vivo

The mechanism of ultrasound thrombolysis (UT) is generally attributed to cavitation. The insufficiency of microbubbles (MB) to serve as cavitation nuclei in the vessel-obstructing thrombi significantly reduces the effectiveness of UT. Taking advantage of the widely performed catheter-directed therapy (CDT), in a thrombo-embolized rabbit IVC model with a simultaneous catheter directed rt-PA thrombolysis procedure, guided moderate mechanical index longer pulses from a modified diagnostic ultrasound transducer, combined with an intraclot infusion of MB, significantly accelerated the thrombolysis process. The higher thrombolysis efficacy score and consistent elevated post-treatment plasma concentration level of D-Dimer, a product of fibrinolysis, both indicated the superiority of CDT + UT over CDT/UT alone. Pathologic examination of the treated occluded IVC segments revealed an almost complete dissolution of the thrombi treated with CDT + UT. There was no evidences of thrombo-embolism or local thrombus formation in the cardiac-pulmonary vessels. Combined with intraclot infusion of MB, guided longer pulse ultrasound from a diagnostic transducer is able to safely and significantly improve a catheter-directed thrombolysis procedure. It thus has the potential to achieve earlier clot removal, administration of a lower dosage of thrombolytic agent and, consequently, a lower incidence of thrombolysis-related side effects.

Acute pulmonary embolism after post-traumatic spinal epidural hematoma: Use of catheter-direct treatment

We report the case of a 35-year-old man who developed a massive pulmonary embolism (PE) after spine surgery. After an accidental axial fall, the patient developed a spinal epidural hematoma (SHE). Because major trauma, recent surgery and known bleeding risk are considered absolute contraindications to systemic thrombolysis, the patient was treated with catheter-directed therapy (CDT). CDT remains a useful treatment in massive PE, especially when systemic thrombolysis is contraindicated or has failed.