Incidence of Mortality and Complications in High-Risk Pulmonary Embolism: A Systematic Review and Meta-Analysis

A Practical Clinical Approach to Navigate Pulmonary Embolism Management: A Primer and Narrative Review of the Evolving Landscape

Advances in imaging, pharmacological, and procedural technologies have rapidly expanded the care of pulmonary embolism. Earlier, more accurate identification and quantification has enhanced risk stratification across the spectrum of the disease process, with a number of clinical tools available to prognosticate outcomes and guide treatment. Direct oral anticoagulants have enabled a consistent and more convenient long-term therapeutic option, with a greater shift toward outpatient treatment for a select group of low-risk patients. The array of catheter-directed therapies now available has contributed to a more versatile and nuanced armamentarium of treatment options, including ultrasound-facilitated thrombolysis and mechanical thrombectomy. Research into supportive care for pulmonary embolism have explored the optimal use of vasopressors and volume resuscitation, as well as utilization of various devices, including right ventricular mechanical support and extracorporeal membrane oxygenation. Even in the realm of surgery, outcomes have steadily improved in experienced centers. This rapid expansion in diagnostic and therapeutic data has necessitated implementation of pulmonary embolism response teams to better interpret the available evidence, manage the utilization of advanced therapies, and coordinate multidisciplinary care. We provide a narrative review of the risk stratification and management of pulmonary embolism, with a focus on structuralizing the multidisciplinary approach and organizing the literature on new and emerging therapies.

Interventional Therapies and Mechanical Circulatory Support for Acute Pulmonary Embolism

Acute pulmonary embolism (PE) represents the third leading cause of cardiovascular mortality, with most PE-related mortality associated with acute right ventricular (RV) failure. Despite an increase in attention to acute PE with new endovascular devices for therapy and the adoption of multidisciplinary clinical treatment teams, mortality rates remain high in patients who present with PE-related hemodynamic compromise. Currently, the advanced treatment modalities for acute high-risk and intermediate high-risk PE are limited to several interventional modalities-open surgical embolectomy and systemic fibrinolytic agents. The purpose of this state-of-the-art review is to describe modern therapeutic techniques and strategies (both interventional and surgical) and the role of mechanical circulatory support (MCS) for hemodynamic compromise in PE.

Large-bore Aspiration Thrombectomy with the FlowTriever System for the Treatment of Pulmonary Embolism: A Large Single-Center Retrospective Analysis

PURPOSE

Evaluate the outcomes of patients undergoing large-bore aspiration thrombectomy for the treatment of pulmonary embolism at a large university medical center.

MATERIALS AND METHODS

All patients treated for pulmonary embolism with the FlowTriever System (Inari Medical, Irvine, CA) between September 2019 and January 2023 were retrospectively analyzed. The primary safety and effectiveness outcomes included 7- and 30-day all-cause mortality, major bleeding, procedure-associated clinical decompensation, pulmonary vascular or cardiac injury, and pulmonary artery pressure reduction. Additional outcomes included technical success (completing thrombectomy with the device as intended), changes in hemodynamics and supplemental oxygen requirements, and postprocedural intensive care unit stay.

RESULTS

A total of 286 patients were identified. The mean age was 60.5 years, and 90.9% of patients presented with intermediate-risk pulmonary embolism. Technical success was achieved in 96.9% (n = 277) of cases. The average reduction in mean pulmonary arterial pressure was 6.8 mmHg, from 28.7 ± 9.0 to 21.9 ± 8.0 mmHg (p < 0.0001). Two major bleeds (0.7%), 2 pulmonary vascular injuries (0.7%), and 4 (1.4%) procedure-associated decompensations were reported, but no device-related deaths occurred. The mean post-procedure intensive care unit stay was 2.0 ± 4.1 days, and 49.3% of patients had no postprocedural intensive care unit admittance. The overall 7-day and 30-day all-cause mortality rates were 2.4% and 6.7%, respectively, with a 30-day pulmonary embolism-related mortality rate of 3.5%.

CONCLUSION

This non-industry-sponsored single-center analysis of large-bore aspiration thrombectomy in a large population corroborates the findings of other studies and confirms that this approach is safe and effective for the treatment high- and intermediate-risk pulmonary embolism.

LEVEL OF EVIDENCE IV

Retrospective observational study.

Percutaneous pulmonary thrombectomy with aspiration catheters in patients with high-risk pulmonary embolism and absolute contraindication to systemic thrombolysis

BACKGROUND

High-risk Pulmonary Embolism (PE) mortality remains very high. Systemic thrombolysis is effective but carries significant complications and contraindications related to the hemorrhagic risk. Percutaneous thrombectomy using aspiration catheters may be an alternative in patients with a high bleeding risk.

OBJECTIVE

This study aimed to evaluate the results of catheter-directed thrombectomy using aspiration dedicated catheters in patients with high-risk PE and absolute contraindication to systemic thrombolysis, with specific focus on procedural success, safety, and in-hospital outcomes.

METHODS

A prospective study enrolled all consecutive patients diagnosed with high-risk pulmonary embolism and absolute contraindication to systemic thrombolysis, who underwent percutaneous pulmonary thrombectomy using dedicated aspiration catheters. The study documented the effectiveness and complications of the procedure, as well as patient outcomes at discharge and during the follow-up period.

RESULTS

Thirteen patients underwent percutaneous pulmonary thrombectomy using aspiration dedicated catheters. The procedure was successful for all patients, resulting in hemodynamic and respiratory improvement within the first 24 h. No deaths attributable to cardiovascular or respiratory causes occurred during admission or follow-up. Furthermore, no serious adverse events or complications were reported during the procedure or hospitalization.

CONCLUSIONS

Percutaneous pulmonary thrombectomy with dedicated aspiration catheters in patients with high-risk pulmonary embolism and contraindications to systemic thrombolysis was associated with excellent clinical results and low rate of complications.

Safety and Efficacy of Reduced-Dose Versus Full-Dose Alteplase for Acute Pulmonary Embolism: A Multicenter Observational Comparative Effectiveness Study

OBJECTIVES

Systemic thrombolysis improves outcomes in patients with pulmonary embolism (PE) but is associated with the risk of hemorrhage. The data on efficacy and safety of reduced-dose alteplase are limited. The study objective was to compare the characteristics, outcomes, and complications of patients with PE treated with full- or reduced-dose alteplase regimens.

DESIGN

Multicenter retrospective observational study.

SETTING

Tertiary care hospital and 15 community and academic centers of a large healthcare system.

PATIENTS

Hospitalized patients with PE treated with systemic alteplase.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Pre- and post-alteplase hemodynamic and respiratory variables, patient outcomes, and complications were compared. Propensity score (PS) weighting was used to adjust for imbalances of baseline characteristics between reduced- and full-dose patients. Separate analyses were performed using the unweighted and weighted cohorts. Ninety-eight patients were treated with full-dose (100 mg) and 186 with reduced-dose (50 mg) regimens. Following alteplase, significant improvements in shock index, blood pressure, heart rate, respiratory rate, and supplemental oxygen requirements were observed in both groups. Hemorrhagic complications were lower with the reduced-dose compared with the full-dose regimen (13% vs. 24.5%, p = 0.014), and most were minor. Major extracranial hemorrhage occurred in 1.1% versus 6.1%, respectively ( p = 0.022). Complications were associated with supratherapeutic levels of heparin anticoagulation in 37.5% of cases and invasive procedures in 31.3% of cases. The differences in complications persisted after PS weighting (15.4% vs. 24.7%, p = 0.12 and 1.3% vs. 7.1%, p = 0.067), but did not reach statistical significance. There were no significant differences in mortality, discharge destination, ICU or hospital length of stay, or readmission after PS weighting.

CONCLUSIONS

In a retrospective, PS-weighted observational study, when compared with the full-dose, reduced-dose alteplase results in similar outcomes but fewer hemorrhagic complications. Avoidance of excessive levels of anticoagulation or invasive procedures should be considered to further reduce complications.

Trends in Discharge Rates for Acute Pulmonary Embolism in U.S. Emergency Departments

BACKGROUND

Outpatient management of select patients with low-risk acute pulmonary embolism (PE) has been proven to be safe and effective, yet recent evidence suggests that patients are still managed with hospitalization. Few studies have assessed contemporary real-world trends in discharge rates from U.S. emergency departments (EDs) for acute PE.

OBJECTIVE

To evaluate whether the proportion of discharges from EDs for acute PE changed between 2012 and 2020 and which baseline characteristics are associated with ED discharge.

DESIGN

Serial cross-sectional analysis.

SETTING

U.S. EDs participating in the National Hospital Ambulatory Medical Care Survey.

PATIENTS

Patients with ED visits for acute PE between 2012 and 2020.

MEASUREMENTS

National trends in the proportion of discharges for acute PE and factors associated with ED discharge.

RESULTS

Between 2012 and 2020, there were approximately 1 635 300 visits for acute PE. Overall, ED discharge rates remained constant over time, with rates of 38.2% (95% CI, 17.9% to 64.0%) between 2012 and 2014 and 33.4% (CI, 21.0% to 49.0%) between 2018 and 2020 (adjusted risk ratio, 1.01 per year [CI, 0.89 to 1.14]). No baseline characteristics, including established risk stratification scores, were predictive of an increased likelihood of ED discharge; however, patients at teaching hospitals and those with private insurance were more likely to receive oral anticoagulation at discharge. Only 35.9% (CI, 23.9% to 50.0%) of patients who were considered low-risk according to their Pulmonary Embolism Severity Index (PESI) class, 33.1% (CI, 21.6% to 47.0%) according to simplified PESI score, and 34.8% (CI, 23.3% to 48.0%) according to hemodynamic stability were discharged from the ED setting.

LIMITATIONS

Cross-sectional survey design and inability to adjudicate diagnoses.

CONCLUSION

In a representative nationwide sample, rates of discharge from the ED for acute PE appear to have remained constant between 2012 and 2020. Only one third of low-risk patients were discharged for outpatient management, and rates seem to have stabilized. Outpatient management of low-risk acute PE may still be largely underutilized in the United States.

PRIMARY FUNDING SOURCE

None.

Mechanical Thrombectomy for High-Risk Pulmonary Embolism: Insights From the US Cohort of the FLASH Registry

Background

Acute mortality for high-risk, or massive, pulmonary embolism (PE) is almost 30% even when treated using advanced therapies. This analysis assessed the safety and effectiveness of mechanical thrombectomy (MT) for high-risk PE.

Methods

The prospective, multicenter FlowTriever All-comer Registry for Patient Safety and Hemodynamics (FLASH) study is designed to evaluate real-world PE patient outcomes after MT with the FlowTriever System (Inari Medical). In this study, acute outcomes through 30 days were evaluated for the subset of patients with high-risk PE as determined by the sites and following European Society of Cardiology guidelines. An independent medical monitor adjudicated adverse events (AEs), including major AEs: device-related mortality, major bleeding, or intraprocedural device-related or procedure-related AEs.

Results

Of the 799 patients in the US cohort, 63 (7.9%) were diagnosed with high-risk PE; 30 (47.6%) patients showed a systolic blood pressure <90 mm Hg, 29 (46.0%) required vasopressors, and 4 (6.3%) experienced cardiac arrest. The mean age of patients with high-risk PE was 59.4 ± 15.6 years, and 34 (54.0%) were women. At baseline, 45 (72.6%) patients were tachycardic, 18 (54.5%) showed elevated lactate levels of ≥2.5 mM, and 21 (42.9%) demonstrated depressed cardiac index of <2 L/min/m2. Immediately after MT, heart rate improved to 93.5 ± 17.9 bpm. Twenty-five (42.4%) patients did not require an overnight stay in the intensive care unit, and no mortalities or major AEs occurred through 48 hours. Moreover, no mortalities occurred in 61 (96.8%) patients followed up through the 30-day visit.

Conclusions

In this cohort of 63 patients with high-risk PE, MT was safe and effective, with no acute mortalities reported. Further prospective data are needed in this population.

Outcomes in High-Risk Pulmonary Embolism Patients Undergoing FlowTriever Mechanical Thrombectomy or Other Contemporary Therapies: Results From the FLAME Study

BACKGROUND

Hemodynamically unstable high-risk, or massive, pulmonary embolism (PE) has a reported in-hospital mortality of over 25%. Systemic thrombolysis is the guideline-recommended treatment despite limited evidence. The FLAME study (FlowTriever for Acute Massive PE) was designed to generate evidence for interventional treatments in high-risk PE.

METHODS

The FLAME study was a prospective, multicenter, nonrandomized, parallel group, observational study of high-risk PE. Eligible patients were treated with FlowTriever mechanical thrombectomy (FlowTriever Arm) or with other contemporary therapies (Context Arm). The primary end point was an in-hospital composite of all-cause mortality, bailout to an alternate thrombus removal strategy, clinical deterioration, and major bleeding. This was compared in the FlowTriever Arm to a prespecified performance goal derived from a contemporary systematic review and meta-analysis.

RESULTS

A total of 53 patients were enrolled in the FlowTriever Arm and 61 in the Context Arm. Context Arm patients were primarily treated with systemic thrombolysis (68.9%) or anticoagulation alone (23.0%). The primary end point was reached in 9/53 (17.0%) FlowTriever Arm patients, significantly lower than the 32.0% performance goal (P<0.01). The primary end point was reached in 39/61 (63.9%) Context Arm patients. In-hospital mortality occurred in 1/53 (1.9%) patients in the FlowTriever Arm and in 18/61 (29.5%) patients in the Context Arm.

CONCLUSIONS

Among patients selected for mechanical thrombectomy with the FlowTriever System, a significantly lower associated rate of in-hospital adverse clinical outcomes was observed compared with a prespecified performance goal, primarily driven by low all-cause mortality of 1.9%.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04795167.