A Prospective, Single-Arm, Multicenter Trial of Ultrasound-Facilitated, Catheter-Directed, Low-Dose Fibrinolysis for Acute Massive and Submassive Pulmonary Embolism: The SEATTLE II Study

In-hospital and readmission outcomes of patients with cancer admitted for pulmonary embolism treated with or without catheter-based therapy

BACKGROUND

Cancer patients are at risk of pulmonary embolism (PE). Catheter-based therapies (CBT) are novel reperfusion options for PE though data in patients with cancer is lacking.

STUDY DESIGN AND METHODS

Patients with intermediate- or high-risk PE were identified using the National Readmission Database (NRD) from 2017 to 2020. Primary outcome were in-hospital death and 90-day readmission. Secondary outcomes were in-hospital bleeding, 90-day readmission for venous thromboembolism (VTE)-related or right heart failure-related reasons and bleeding. Propensity scores were estimated using logistic regression and inverse-probability treatment weighting (IPTW) was utilized to compare outcomes between CBT and no CBT as well as CBT versus systemic thrombolysis.

RESULTS

A total of 7785 patients were included (2511 with high-risk PE) of whom 1045 (13.4%) were managed with CBT. After IPTW, CBT was associated with lower rates of index hospitalization death (OR 0.89, 95% CI 0.83-0.96) and 90-day readmission (HR 0.75, 95% CI 0.69-0.81) but higher rates of in-hospital bleeding (OR 1.11, 95% CI 1.03-1.20) which was predominantly post-procedural bleeding. CBT was associated with lower risk of major bleeding (20.8% vs 24.8%; OR 0.80, 95% CI 0.68-0.94) compared with systemic thrombolysis.

INTERPRETATION

Among patients with cancer with intermediate or high-risk PE, CBT was associated with lower in-hospital death and 90-day readmission. CBT was also associated with decreased risk of index hospitalization major bleeding compared with systemic thrombolysis. Prospective, randomized trials with inclusion of patients with cancer are needed to confirm these findings.

Endovascular treatments of acute pulmonary embolism in the post-fibrinolytic era: an up-to-date review

Pulmonary embolism (PE) is a significant contributor to global cardiovascular-related mortality that mainly depends on the severity of the event. The treatment approach for intermediate and high-risk PE remains a topic of debate due to the fine balance between hemodynamic deterioration and bleeding risk. The initial treatment choice for intermediate-risk PE with hemodynamic deterioration and high-risk PE is historically systemic thrombolysis, but this approach is not always effective and carries a notable risk of severe bleeding. For such patients, various interventional treatments have been introduced to clinical practice, including catheter-directed lysis (CDL), ultrasound-assisted CDL, pharmacomechanical CDL, and aspiration thrombectomy. However, the optimal treatment approach remains uncertain. Encouraging outcomes have been presented assessing the novel endovascular treatments, in terms of reducing right ventricular dysfunction and improving hemodynamic stability, opening the possibility of using these devices to prevent hemodynamic instability in less severe cases. However, ongoing randomized trials that assess the efficacy and the association with mortality, especially for aspiration devices, have not yet published their final results. This article aims to offer a comprehensive update of the available catheter-directed therapies for PE, with a focus on novel mechanical thrombectomy techniques, assessing their safety and efficacy, after comparison to the conventional treatment. CRITICAL RELEVANCE STATEMENT: This is a comprehensive review of the indications of use, techniques, and clinical outcomes of the most novel endovascular devices for the treatment of pulmonary embolism. KEY POINTS: Mechanical thrombectomy is an effective tool for patients with PE. Aspiration devices prevent hemodynamic deterioration. Catheter directed therapy reduces bleeding complications.

A novel method for the evaluation of right ventricular dysfunction in acute pulmonary embolism: Myocardial work indices

PURPOSE

The presence of right ventricular dysfunction indicates a higher risk status in patients with pulmonary embolism (PE). The RV strain evaluated by speckle-tracking echocardiography seems to be more reliable method in the evaluation of RV dysfunction as compared to standard echocardiographic measures. In this study, we aimed to determine the value of myocardial-work indices in evaluating serial changes of RV function in acute PE.

METHODS

Our study comprised 83 consecutive acute PE patients who admitted to our tertiary cardiovascular hospital. Echocardiography was performed within the first 24-hours of hospitalization, and RV and LV myocardial-work parameters were obtained along with standard echocardiographic parameters. The change in the RV/LVr detected on tomography was selected as the primary outcome measure, and its' predictors were analyzed with classical linear regression and a generalized additive model (GAM).

RESULTS

Among the LV-RV strain and myocardial work parameters, the RV global longitudinal strain (GLS) has borderline statistical significance in predicting the RV/LVr change whereas the RV global work efficiency (RV-GWE) strongly predicted RV/LVr change (p: 0.049 and <0.001, respectively).

CONCLUSION

In this study, classical linear regression and GAM analyses showed that RV-GWE seems to offer a better prediction of RV/LVr change in patients with acute PE.

Catheter Interventions for Pulmonary Embolism: Mechanical Thrombectomy Versus Thrombolytics

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

Long-term outcomes and predictors of mortality in patients with pulmonary embolism undergoing catheter-directed thrombolysis: a 10-year retrospective study

BACKGROUND

Data regarding long-term outcomes of catheter-directed thrombolysis (CDT) post intermediate risk pulmonary embolism (PE), the choice of anticoagulation, and factors affecting mortality are not well studied.

METHODS

We conducted a ten-year retrospective observational chart review of patients undergoing CDT for intermediate-risk PE. Patients were followed for a period of 1 to a maximum of 5 years from the PE event. Multivariate regression analysis was used to identify independent predictors of mortality post-CDT.

RESULTS

We had a total of 373 patients in our study. Significant 5-year mortality was observed (18.7 %) in our patient population, with a 9.2 % cardiopulmonary cause of death. Rate was highest in patients without anticoagulation (78.5 %) and least in patients on apixaban [10.9 %, absolute risk reduction - 63.8 % (40.91 % - 86.60 %)]. Age, female sex and no anticoagulation were independently associated with mortality.

CONCLUSION

CDT for intermediate-risk PE has a high 5-year mortality with no anticoagulation as the only modifiable risk factor.

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.

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.

Management of high-risk pulmonary embolism in the emergency department: A narrative review

BACKGROUND

High-risk pulmonary embolism (PE) is a complex, life-threatening condition, and emergency clinicians must be ready to resuscitate and rapidly pursue primary reperfusion therapy. The first-line reperfusion therapy for patients with high-risk PE is systemic thrombolytics (ST). Despite consensus guidelines, only a fraction of eligible patients receive ST for high-risk PE.

OBJECTIVE

This review provides emergency clinicians with a comprehensive overview of the current evidence regarding the management of high-risk PE with an emphasis on ST and other reperfusion therapies to address the gap between practice and guideline recommendations.

DISCUSSION

High-risk PE is defined as PE that causes hemodynamic instability. The high mortality rate and dynamic pathophysiology of high-risk PE make it challenging to manage. Initial stabilization of the decompensating patient includes vasopressor administration and supplemental oxygen or high-flow nasal cannula. Primary reperfusion therapy should be pursued for those with high-risk PE, and consensus guidelines recommend the use of ST for high-risk PE based on studies demonstrating benefit. Other options for reperfusion include surgical embolectomy and catheter directed interventions.

CONCLUSIONS

Emergency clinicians must possess an understanding of high-risk PE including the clinical assessment, pathophysiology, management of hemodynamic instability and respiratory failure, and primary reperfusion therapies.

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

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

Single-session catheter-directed lysis using adjunctive clot fragmentation with power pulse spray only is a fast, safe, and effective option for acute pulmonary embolism

OBJECTIVE

Single-session, catheter-directed thrombolysis (CDT) with adjunctive power pulse spray (PPS) only, without thrombectomy, was evaluated for its safety and effectiveness. We performed a single-center, retrospective analysis of prospectively collected data.

METHODS

Patients with high-risk or intermediate-risk pulmonary embolism (PE) who met the inclusion criteria and underwent a single session of CDT-PPS were included in the study. The primary outcomes assessed were technical and clinical success and major adverse events. Secondary outcomes included effectiveness based on pre- and postintervention clinical examination, radiographic findings, and reversal of right ventricular dysfunction at 48 hours and 4 weeks after discharge on echocardiography and computed tomography pulmonary angiography. The length of stay in the intensive care unit and overall admission were also analyzed. A return to premorbid exercise tolerance was evaluated at 12 months after the procedure.

RESULTS

Between May 2016 and January 2023, 104 patients at the Wollongong Hospital were diagnosed with high- or intermediate-risk PE and underwent CDT-PPS. Of the 104 patients, 49 (47%) were considered to have high-risk PE and 55 (53%) intermediate-risk PE. Eleven patients (11%) had absolute contraindications and 49 patients (47%) had relative contraindications to systemic thrombolysis. Technical success was achieved in 102 patients (98%). Survival was 99% at 48 hours, 96% at 4 weeks, and 91% at 12 months. At 4 weeks, echocardiography showed 98% of patients had no evidence of right heart dysfunction, and computed tomography pulmonary angiography showed complete resolution of PE in 72%. There were no major adverse events at 48 hours. The median intensive care unit length of stay was 1 day, and the overall length of stay was 6 days. At 12 months, 96% had returned to their premorbid status.

CONCLUSIONS

The CDT-PPS technique is fast, safe, and effective in the treatment of high- and intermediate-risk PE, even in patients with a high bleeding risk, and should be considered as first-line management when the skills and resources are available. Further multicenter prospective studies are needed to corroborate these results.

Evidence-Based Update on Transcatheter Therapies for Pulmonary Embolism

PURPOSE OF REVIEW

Pulmonary embolism (PE) remains a leading cause of cardiovascular morbidity and mortality. Multiple new therapies are in development and under study to improve our contemporary care of patients with PE. We review and compare here these novel therapeutics and technologies.

RECENT FINDINGS

Multiple novel therapeutic devices have been developed and are under active study. This work has advanced the care of patients with intermediate and high-risk PE. Novel therapies are improving care of complex PE patients. These have inspired large multicenter international randomized controlled trials that are actively recruiting patients to advance the care of PE. These studies will work towards advancing guidelines for clinical care of patients with PE.

Catheter-based therapy for high-risk or intermediate-risk pulmonary embolism: death and re-hospitalization

BACKGROUND AND AIMS

Catheter-based therapies (CBTs) have been developed as a treatment option in patients with pulmonary embolism (PE). There remains a paucity of data to inform decision-making in patients with intermediate-risk or high-risk PE. The aim of this study was to characterize in-hospital and readmission outcomes in patients with intermediate-risk or high-risk PE treated with vs. without CBT in a large retrospective registry.

METHODS

Patients hospitalized with intermediate-risk or high-risk PE were identified using the 2017-20 National Readmission Database. In-hospital outcomes included death and bleeding and 30- and 90-day readmission outcomes including all-cause, venous thromboembolism (VTE)-related and bleeding-related readmissions. Inverse probability of treatment weighting (IPTW) was utilized to compare outcomes between CBT and no CBT.

RESULTS

A total of 14 903 [2076 (13.9%) with CBT] and 42 829 [8824 (20.6%) with CBT] patients with high-risk and intermediate-risk PE were included, respectively. Prior to IPTW, patients with CBT were younger and less likely to have cancer and cardiac arrest, receive systemic thrombolysis, or be on mechanical ventilation. In the IPTW logistic regression model, CBT was associated with lower odds of in-hospital death in high-risk [odds ratio (OR) 0.83, 95% confidence interval (CI) 0.80-0.87] and intermediate-risk PE (OR 0.76, 95% CI 0.70-0.83). Patients with high-risk PE treated with CBT were associated with lower risk of 90-day all-cause [hazard ratio (HR) 0.77, 95% CI 0.71-0.83] and VTE (HR 0.46, 95% CI 0.34-0.63) readmission. Patients with intermediate-risk PE treated with CBT were associated with lower risk of 90-day all-cause (HR 0.75, 95% CI 0.72-0.79) and VTE (HR 0.66, 95% CI 0.57-0.76) readmission.

CONCLUSIONS

Among patients with high-risk or intermediate-risk PE, CBT was associated with lower in-hospital death and 90-day readmission. Prospective, randomized trials are needed to confirm these findings.

Outcomes With Hybrid Catheter-Directed Therapy Compared With Aspiration Thrombectomy for Patients With Intermediate-High Risk Pulmonary Embolism

PURPOSE

Intermediate-high-risk pulmonary embolism (IHR PE) is a challenging form of embolism obstruction that causes right ventricular (RV) dysfunction. The optimal management of IHR PE has not been established. This single-center prospective, observational study aimed to evaluate the efficacy and safety of complex catheter-directed therapy (CDT) - catheter-directed mechanical aspiration thrombectomy (CDMT) supplemented with catheter-directed thrombolysis (hybrid CDT) in comparison to CDMT alone for IHR PE.

METHODS

A propensity score based on the pulmonary embolism severity index class and Miller obstruction index (MOI) was calculated, and 21 hybrid CDT cases (mean age 54.8 (14.7) years, 9/21 women) were matched with 21 CDMT cases (mean age 58.8 (14.9) years, 13/21 women). The baseline demographics, clinical, and treatment characteristics were analyzed.

RESULTS

No significant differences were detected regarding baseline demographics and PE severity parameters. Hybrid CDT demonstrated a higher reduction in mean pulmonary artery pressure (mPAP) (hybrid CDT: median mPAP reduction 8 mmHg (IQR: 6-10 mmHg) vs CDMT: median mPAP reduction 6 mmHg (IQR: 4-7 mmHg); P = 0.019), MOI score (hybrid CDT: median change - 5 points (IQR: 5-6 points) vs CDMT median change - 3 points (IQR: 3-5 points); P = 0.019), and median RV: left ventricular ratio (hybrid CDT: median change 0.4 (IQR: 0.3-0.45) vs CDMT median change 0.26 (IQR: 0.2-0.4); P = 0.007). No major bleeding was observed. Both the hybrid CDT and CDMT alone treatments are safe and effective in managing IHR PE.

CONCLUSIONS

Hybrid CDT is a promising technique for the management of IHR PE with insufficient thrombus load reduction by CDMT.

TRIAL REGISTRATION

NCT0447356-registration date 16 July 2020.

Ultrasound-assisted endovascular thrombolysis versus large-bore thrombectomy in acute intermediate-high risk pulmonary embolism: The propensity-matched EKNARI cohort study

BACKGROUND

Ultrasound-assisted thrombolysis (USAT) and large-bore-thrombectomy (LBT) are under investigation for the treatment of intermediate-high and high-risk pulmonary embolisms (PE). Comparative studies investigating both devices are scarce.

AIMS

This study aimed to compare the safety and efficacy of the two most frequently used devices for treatment of acute PE.

METHODS

This multicenter, retrospective study included 125 patients undergoing LBT or USAT for intermediate- or high-risk PE between 2019 and 2023. Nearest neighbor propensity matching with logistic regression was used to achieve balance on potential confounders. The primary outcome was the change in the right to left ventricular (RV/LV) ratio between baseline and 24 h.

RESULTS

A total of 125 patients were included. After propensity score matching, 95 patients remained in the sample, of which 69 (73%) underwent USAT and 26 (27%) LBT. The RV/LV ratio decrease between baseline and 24 h was greater in the LBT than in the USAT group (adjusted between-group difference: -0.10, 95% CI: -0.16 to -0.04; p = 0.001). Both procedures were safe and adverse events occurred rarely (10% following USAT vs. 4% following LBT; p = 0.439).

CONCLUSION

In acute intermediate-high and high-risk PE, both LBT and USAT were feasible and safe. The reduction in RV/LV ratio was greater following LBT than USAT. Further randomized controlled trials are needed to confirm these findings.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Cutting-Edge Techniques and Drugs for the Treatment of Pulmonary Embolism: Current Knowledge and Future Perspectives

Pulmonary embolism (PE) is a potentially life-threatening condition requiring prompt diagnosis and treatment. Recent advances have led to the development of newer techniques and drugs aimed at improving PE management, reducing its associated morbidity and mortality and the complications related to anticoagulation. This review provides an overview of the current knowledge and future perspectives on PE treatment. Anticoagulation represents the first-line treatment of hemodynamically stable PE, direct oral anticoagulants being a safe and effective alternative to traditional anticoagulation: these drugs have a rapid onset of action, predictable pharmacokinetics, and low bleeding risk. Systemic fibrinolysis is suggested in patients with cardiac arrest, refractory hypotension, or shock due to PE. With this narrative review, we aim to assess the state of the art of newer techniques and drugs that could radically improve PE management in the near future: (i) mechanical thrombectomy and pulmonary embolectomy are promising techniques reserved to patients with massive PE and contraindications or failure to systemic thrombolysis; (ii) catheter-directed thrombolysis is a minimally invasive approach that can be suggested for the treatment of massive or submassive PE, but the lack of large, randomized controlled trials represents a limitation to widespread use; (iii) novel pharmacological approaches, by agents inhibiting thrombin-activatable fibrinolysis inhibitor, factor Xia, and the complement cascade, are currently under investigation to improve PE-related outcomes in specific settings.

Integration of Extracorporeal Membrane Oxygenation into the Management of High-Risk Pulmonary Embolism: An Overview of Current Evidence

High-risk pulmonary embolism (PE) refers to a large embolic burden causing right ventricular failure and hemodynamic instability. It accounts for approximately 5% of all cases of PE but contributes significantly to overall PE mortality. Systemic thrombolysis is the first-line revascularization therapy in high-risk PE. Surgical embolectomy or catheter-directed therapy is recommended in patients with an absolute contraindication to systemic thrombolysis. Extracorporeal membrane oxygenation (ECMO) provides respiratory and hemodynamic support for the most critically ill PE patients with refractory cardiogenic shock or cardiac arrest. The complex management of these individuals requires urgent yet coordinated multidisciplinary care. In light of existing evidence regarding the utility of ECMO in the management of high-risk PE patients, a number of possible indications for ECMO utilization have been suggested in the literature. Specifically, in patients with refractory cardiac arrest, resuscitated cardiac arrest, or refractory shock, including in cases of failed thrombolysis, venoarterial ECMO (VA-ECMO) should be considered, either as a bridge to percutaneous or surgical embolectomy or as a bridge to recovery after surgical embolectomy. We review here the current evidence on the use of ECMO as part of the management strategy for the highest-risk presentations of PE and summarize the latest data in this indication.

Pulmonary embolism response teams. A description of the first 36-month Australian experience

BACKGROUND

High/intermediate-risk pulmonary embolism (PE) confers increased risk of cardiovascular morbidity and mortality. International guidelines recommend the formation of a PE response team (PERT) for PE management because of the complexity of risk stratification and emerging treatment options. However, there are currently no available Australian data regarding outcomes of PE managed through a PERT.

AIMS

To analyse the clinical and outcome data of patients from an Australian centre with high/intermediate-risk PE requiring PERT-guided management.

METHODS

We performed a retrospective observational study of 75 consecutive patients with high/intermediate-risk PE who had PERT involvement, between August 2018 and July 2021. We recorded clinical and interventional data at the time of PERT and assessed patient outcomes up to 30 days from PERT initiation. We used unpaired t tests to compare right to left ventricular (RV/LV) ratios by computed tomography criteria or transthoracic echocardiogram (TTE) at baseline and after interventions.

RESULTS

Data were available for 74 patients. Initial computed tomography pulmonary angiography RV/LV ratio was increased at 1.65 ± 0.5 and decreased to 1.30 ± 0.29 following PERT-guided interventions (P < 0.001). TTE RV/LV ratio also decreased following PERT-guided management (1.09 ± 0.19 vs 0.93 ± 0.17; P < 0.001). 20% of patients had any bleeding complication, but two-thirds were mild, not requiring intervention. All-cause mortality was 6.8%, and all occurred within the first 7 days of admission.

CONCLUSION

The PERT model is feasible in a large Australian centre in managing complex and time-critical PE. Our data demonstrate outcomes comparable with existing published international PERT data. However, successful implementation at other Australian institutions may require adequate centre-specific resource availability and the presence of multispeciality input.

Early predictors of clinical deterioration in intermediate-high risk pulmonary embolism: clinical needs, research imperatives, and pathways forward

A subset of intermediate-high risk pulmonary embolism (PE) patients will suffer clinical deterioration in the early hours following the acute event. Current evidence-based guidelines for the management of acute PE have provided limited direction for identification of which intermediate-high risk PE patients will go on to develop haemodynamic decompensation. Furthermore, a paucity of data further hampers guideline recommendations regarding the optimal approach and duration of intensive monitoring, best methods to assess the early response to anticoagulation, and the ideal window for reperfusion therapy, if decompensation threatens. The aim of the present article is to identify the current unmet needs related to the early identification of intermediate-high risk PE patients at higher risk of clinical deterioration and mortality during the early hours after the acute cardiovascular event and suggest some potential strategies to further explore gaps in the literature.

Impact of a pulmonary embolism response team (PERT) in the prognosis of patients with acute symptomatic pulmonary embolism

BACKGROUND

The effect of a pulmonary embolism response team (PERT) in the short-term prognosis of patients with acute symptomatic pulmonary embolism (PE) lacks clarity. We therefore aimed at evaluating the effect of a PERT team on short-term mortality among patients with acute PE.

METHODS

We retrospectively reviewed consecutive patients with acute symptomatic PE enrolled in a single-center registry between 2007 and 2022. We used propensity score matching to compare treatment effects for patients with similar predicted probabilities of receiving management by the PERT team. The primary outcome was all-cause mortality within 30 days following the diagnosis of PE. The secondary outcome was 30-day PE-related mortality.

RESULTS

Of the 2,902 eligible patients who had acute symptomatic PE, 223 (7.7%; 95% confidence interval [CI], 6.7%-8.7%) were managed by the PERT team. Two hundred and seven patients who were treated by the PERT were matched with 207 patients who were not. Matched pairs did not show a statistically significant lower all-cause (odds ratio [OR], 1.09; 95% CI, 0.63-1.89) or PE-related death (OR, 1.30; 95% CI, 0.47-3.62) for PERT management compared with no PERT management through 30 days after diagnosis of PE.

CONCLUSIONS

Our results suggest that multidisciplinary care of patients with acute symptomatic PE by a PERT team is not associated with a significant reduction in short-term all-cause or PE-related mortality.

Inducing cavitation within hollow cylindrical radially polarized transducers for intravascular applications

Thrombotic occlusions of large blood vessels are increasingly treated with catheter based mechanical approaches, one of the most prominent being to employ aspiration to extract clots through a hollow catheter lumen. A central technical challenge for aspiration catheters is to achieve sufficient suction force to overcome the resistance of clot material entering into the distal tip. In this study, we examine the feasibility of inducing cavitation within hollow cylindrical transducers with a view to ultimately using them to degrade the mechanical integrity of thrombus within the tip of an aspiration catheter. Hollow cylindrical radially polarized PZT transducers with 3.3/2.5 mm outer/inner diameters were assessed. Finite element simulations and hydrophone experiments were used to investigate the pressure field distribution as a function of element length and resonant mode (thickness, length). Operating in thickness mode (∼5 MHz) was found to be associated with the highest internal pressures, estimated to exceed 23 MPa. Cavitation was demonstrated to be achievable within the transducer under degassed water (10 %) conditions using hydrophone detection and high-frequency ultrasound imaging (40 MHz). Cavitation clouds occupied a substantial portion of the transducer lumen, in a manner that was dependent on the pulsing scheme employed (10 and 100 μs pulse lengths; 1.1, 11, and 110 ms pulse intervals). Collectively the results support the feasibility of achieving cavitation within a transducer compatible with mounting in the tip of an aspiration format catheter.

Ultrasound-Facilitated, Catheter-Directed Thrombolysis for Acute Pulmonary Embolism

BACKGROUND

Acute pulmonary embolism (APE) poses a significant risk to patient health, with treatment options varying in efficacy and safety. Ultrasound-facilitated catheter-directed thrombolysis (USCDT) has emerged as a potential alternative to conventional catheter-directed thrombolysis (CDT) for patients with intermediate to high-risk APE. This study aimed to compare the efficacy and safety of USCDT versus conventional CDT in patients with intermediate to high-risk APE.

METHODS

This observational retrospective study was conducted at the Armed Forces Hospital, Al-Hada, Taif, the Kingdom of Saudi Arabia (KSA), on 135 patients diagnosed with APE and treated with either USCDT or CDT (58 underwent CDT, while 77 underwent USCDT). The primary efficacy outcome was the change in the right ventricle to the left ventricle (RV/LV) diameter ratio. Secondary outcomes included changes in pulmonary artery systolic pressure and the Miller angiographic obstruction index score. Safety outcomes focused on major bleeding events.

RESULTS

Both USCDT and CDT significantly reduced RV/LV diameter ratio (from 1.35 ± 0.14 to 1.05 ± 0.17, P < 0.001) and systolic pulmonary artery pressure (SPAP) (from 55 ± 7 mmHg to 38 ± 7 mmHg, P < 0.001) at 48- and 12-hours post-procedure, respectively, with no significant differences between treatments. However, USCDT was associated with a significantly lower rate of major bleeding events compared to CDT (0% vs. 3.4%, P = 0.008). Multivariate logistic regression analysis revealed that USCDT was associated with a 71.9% risk reduction of bleeding (OR = 0.281, 95% CI = 0.126 - 0.627, P = 0.002).

CONCLUSIONS

USCDT is a safe and effective alternative to CDT for the treatment of intermediate to high-risk APE, as it significantly reduces the risk of major bleeding.

The effect of ultrasound-assisted thrombolysis studied in blood-on-a-chip

BACKGROUND

Thromboembolism, which leads to pulmonary embolism and ischemic stroke, remains one of the main causes of death. Ultrasound-assisted thrombolysis (UAT) is an effective thrombolytic method. However, further studies are required to elucidate the mechanism of ultrasound on arterial and venous thrombi.

METHODS

We employed the blood-on-a-chip technology to simulate thrombus formation in coronary stenosis and deep vein valves. Subsequently, UAT was conducted on the chip to assess the impact of ultrasound on thrombolysis under varying flow conditions. Real-time fluorescence was used to assess thrombolysis and drug penetration. Finally, scanning electron microscopy and immunofluorescence were used to determine the effect of ultrasound on fibrinolysis.

RESULTS

The study revealed that UAT enhanced the thrombolytic rate by 40% in the coronary stenosis chip and by 10% in the deep venous valves chip. This enhancement is attributed to the disruption of crosslinked fibrin fibers by ultrasound, leading to increased urokinase diffusion within the thrombus and accumulation of plasminogen on the fibrinogen α chain. Moreover, the acceleration of the dissolution rate of thrombi in the venous valve chip by ultrasound was not as significant as that in the coronary stenosis chip.

CONCLUSION

These findings highlight the differential impact of ultrasound on thrombolysis under various flow conditions and emphasize the valuable role of the blood-on-a-chip technology in exploring thrombolysis mechanisms.

Comparison of In-Hospital Outcomes between Early and Late Catheter-Directed Thrombolysis in Acute Pulmonary Embolism: A Retrospective Observational Study

The purpose of this study is to evaluate whether early initiation of catheter-directed thrombolysis (CDT) in patients presenting with acute pulmonary embolism is associated with improved in-hospital outcomes. A retrospective cohort was extracted from the 2016-2019 National Inpatient Sample database, consisting of 21,730 weighted admissions undergoing CDT acute PE. From the time of admission, the sample was divided into early (<48 h) and late interventions (>48 h). Outcomes were measured using regression analysis and propensity score matching. No significant differences in mortality, cardiac arrest, cardiogenic shock, or intracranial hemorrhage (p > 0.05) were found between the early and late CDT groups. Late CDT patients had a higher likelihood of receiving systemic thrombolysis (3.21 [2.18-4.74], p < 0.01), blood transfusion (1.84 [1.41-2.40], p < 0.01), intubation (1.33 [1.05-1.70], p = 0.02), discharge disposition to care facilities (1.32 [1.14-1.53], p < 0.01). and having acute kidney injury (1.42 [1.25-1.61], p < 0.01). Predictors of late intervention were older age, female sex, non-white ethnicity, non-teaching hospital admission, hospitals with higher bed sizes, and weekend admission (p < 0.01). This study represents a comprehensive evaluation of outcomes associated with the time interval for initiating CDT, revealing reduced morbidity with early intervention. Additionally, it identifies predictors associated with delayed CDT initiation. The broader ramifications of these findings, particularly in relation to hospital resource utilization and health disparities, warrant further exploration.

Treatment of acute pulmonary embolism after catheter-directed thrombolysis with dabigatran vs warfarin: results of a multicenter randomized RE-SPIRE trial

BACKGROUND

Thrombolytic therapy is effective method in the high-risk acute pulmonary embolism (PE) treatment. Reduced-dose thrombolysis (RDT) plus oral anticoagulation therapy is effective and safe method in the moderate and severe PE treatment. It is leading to good early and intermediate-term outcomes. In the RE-COVER and RE-COVER II studies, dabigatran showed similar effectiveness as warfarin in the treatment of acute PE. Dabigatran leads to fewer hemorrhagic complications and is not inferior in efficacy to warfarin in the prevention of PE after mechanical fragmentation and RDT (catheter-directed treatment [CDT]+RDT) in patients with high and intermediate to high PE risk. We sought to evaluate the efficacy and safety (incidence of clinically significant recurrence of venous thromboembolic complications and deaths) during a 6-month course of treatment with dabigatran or warfarin in patients with high and intermediate to high acute PE risk after endovascular mechanical thrombus fragmentation procedure with RDT (CDT+RDT).

METHODS

The RE-SPIRE is a prospective, multicenter randomized double-arm study. Over a 5-year period, 66 consecutive patients with symptomatic high and intermediate to high PE risk after endovascular mechanical thrombus fragmentation procedure with RDT (CDT+RDT) were randomized into two groups within the next 48 hours. The first group continued treatment with dabigatran 150 mg twice a day for 6 months; the second group continued treatment with warfarin under the control of international normalized ratio (2.0-3.0) for 6 months. Both groups received low molecular weight heparins for 2 days after surgery. Then, group 1 continued to receive low molecular-weight-heparin for 5 to 7 days, followed by a switch to dabigatran at a dosage of 150 mg two times a day. Group 2 received both low-molecular-weight heparin and warfarin up to an international normalized ratio of >2.0, followed by heparin withdrawal. The follow-up period was 6 months.

RESULTS

There were 63 patients who completed the study (32 in the dabigatran group and 31 in the warfarin group). In both groups, there was a statistically significant decrease in the mean pulmonary artery pressure. The mean pulmonary artery pressure at the 6-month follow-up after surgery was 24 mm Hg (interquartile range, 20.3-29.25 mm Hg) in the dabigatran group and 23 mm Hg (interquartile range, 20.0-26.3 mm Hg) in the warfarin group. The groups did not differ statistically in the deep vein thrombosis dynamics. Partial recanalization occurred in 52.0% vs 73.1% in the dabigatran and warfarin groups, respectively (P = .15). Complete recanalization occurred in 28.0% vs 19.2% in the dabigatran and warfarin groups, respectively (P = .56). The groups did not differ in the frequency of major bleeding events according to the International Society for Thrombosis and Hemostasis (0% vs 3.2% in the dabigatran and warfarin groups, respectively; P = 1.00). However, there were more nonmajor bleeding events in the warfarin group than in the dabigatran group (16.1% vs 0%, respectively; P = .02).

CONCLUSIONS

The results of the study show that dabigatran is comparable in effectiveness to warfarin. Dabigatran has greater safety in comparison with warfarin in the occurrence of all cases of bleeding in the postoperative and long-term periods. Thus, dabigatran may be recommended for the treatment and prevention of PE after CDT with RDT in patients with high and intermediate to high PE risk.

High and intermediate risk pulmonary embolism in the ICU

Pulmonary embolism (PE) is a common and important medical emergency, encountered by clinicians across all acute care specialties. PE is a relatively uncommon cause of direct admission to the intensive care unit (ICU), but these patients are at high risk of death. More commonly, patients admitted to ICU develop PE as a complication of an unrelated acute illness. This paper reviews the epidemiology, diagnosis, risk stratification, and particularly the management of PE from a critical care perspective. Issues around prevention, anticoagulation, fibrinolysis, catheter-based techniques, surgical embolectomy, and extracorporeal support are discussed.

Underuse of reperfusion therapy with systemic thrombolysis in high-risk acute pulmonary embolism in a Portuguese center

INTRODUCTION

Reperfusion therapy is generally recommended in acute high-risk pulmonary embolism (HR-PE), but several population-based studies report that it is underused. Data on epidemiology, management and outcomes of HR-PE in Portugal are scarce.

OBJECTIVE

To determine the reperfusion rate in HR-PE patients, the reasons for non-reperfusion, and how it influences outcomes.

METHODS

In this retrospective cohort study of consecutive HR-PE patients admitted to a thromboembolic disease referral center between 2008 and 2018, independent predictors for non-reperfusion were assessed by multivariate logistic regression. PE-related mortality and long-term MACE (cardiovascular mortality, PE recurrence and chronic thromboembolic disease) were calculated according to the Kaplan-Meier method. Differences stratified by reperfusion were assessed using the log-rank test.

RESULTS

Of 1955 acute PE patients, 3.8% presented with hemodynamic instability. The overall reperfusion rate was 50%: 35 patients underwent systemic thrombolysis, one received first-line percutaneous embolectomy and one rescue endovascular treatment. Independent predictors of non-reperfusion were: age, with >75 years representing 12 times the risk of non-treatment (OR 11.9, 95% CI 2.7-52.3, p=0.001); absolute contraindication for thrombolysis (31.1%), with recent major surgery and central nervous system disease as the most common reasons (OR 16.7, 95% CI 3.2-87.0, p<0.001); and being hospitalized (OR 7.7, 95% CI 1.4-42.9, p=0.020). At a mean follow-up of 2.5±3.3 years, the survival rate was 33.8%. Although not reaching statistical significance for hospital mortality, mortality in the reperfusion group was significantly lower at 30 days, 12 months and during follow-up (relative risk reduction of death of 64% at 12 months, p=0.013). Similar results were found for MACE.

CONCLUSIONS

In this population, the recommended reperfusion therapy was performed in only 50% of patients, with advanced age and absolute contraindications to fibrinolysis being the main predictors of non-reperfusion. In this study, thrombolysis underuse was associated with a significant increase in short- and long-term mortality and events.

Trends and outcomes of lytic-based therapies for high-risk pulmonary embolism: A nationwide analysis

BACKGROUND

Systemic thrombolysis (ST) is the guideline-recommended treatment for high-risk pulmonary embolism (PE), although catheter-directed thrombolysis (CDT) may provide a treatment alternative associated with lower rates of bleeding. Furthermore, the treatment trends and outcomes among those with high-risk PE according to treatment assignments of no lytic therapy (NLT), ST, and CDT are underreported.

METHODS

Patients hospitalized for high-risk PE between 2016 and 2019 were identified by administrative claims codes from the National Readmission Database. Therapy assignment was similarly defined by administrative codes, then stratified into NLT, ST, and CDT cohorts to report patient characteristics, care settings, and clinical outcomes. The primary outcome was in-hospital mortality with rates adjusted for patient and hospital characteristics using multivariable logistic regression. Secondary outcomes included intracranial hemorrhage (ICH), gastrointestinal bleeding (GIB), and 90-day readmission. Over the years of interest, trends in lytic treatment along with concomitant use of mechanical or surgical thrombectomy were reported.

RESULTS

Among 74,516 patients with high-risk PE, 61,569 (82.6%) received NLT, 8445 (11.3%) received ST, and 4502 (6.04%) received CDT. The NLT subgroup, relative to ST and CDT, tended to be older (66.1 ± 15.4, 62.8 ± 15.3, and 63.4 ± 14.4; p < 0.001) and more frequently women (56.0%, 54.4%, and 51.3%; p < 0.001), respectively. The unadjusted in-hospital mortality rate was highest for ST (18.8%, 34.1%, and 18.3% for NLT, ST, and CDT, respectively; p < 0.001) and persisted after multivariable adjustment (adjusted odds ratio (aOR) 0.43; 95% CI 0.38-0.49; p < 0.0001) of in-hospital mortality for CDT relative to ST. The unadjusted rate of ICH or GIB was lowest for NLT (1.0%, 2.0%, and 0.6% for NLT, ST, and CDT, respectively; p < 0.001). CDT, relative to ST, was associated with reduced odds of ICH (aOR 0.32; 95% CI 0.18-0.55; p < 0.0001) and GIB (aOR 0.78; 95% CI 0.62-0.98; p < 0.0001). Readmissions were highest for NLT (21.7%, 9.6%, and 12.1% for NLT, ST, and CDT, respectively; p < 0.001). CDT was associated with a higher incidence of 90-day readmission relative to ST (aOR 1.32; 95% CI 1.10-1.57; p < 0.001). From 2016 to 2019, individual treatment trends were not significantly different, although NLT tended to be offered among smaller and rural hospitals. Rates of concomitant thrombectomy were low in all three treatment groups.

CONCLUSIONS

Among a large, contemporary, US cohort with high-risk PE, over 80% of patients did not receive any form of thrombolysis. High-risk PE that did receive systemic thrombolysis was associated with the highest rates of in-hospital mortality, suggesting opportunities to study the implementation of lytic and nonlytic-based treatments to improve outcomes for those presenting with high-risk PE.

Plasma Fibrinogen Change as a Predictor of Major Bleeding During Catheter-Directed Thrombolysis

BACKGROUND

Our primary objective was to determine the relationship between plasma fibrinogen levels (PFLs) and major bleeding complications during catheter-directed thrombolysis, including final, nadir, and change over time. Furthermore, we sought to evaluate additional predictors of bleeding outcomes, including duration of lysis and total dose of tissue plasminogen activator received.

METHODS

In this multicenter retrospective cohort study, we reviewed all patients undergoing catheter-directed thrombolysis between January 2016 and August 2021. Patients undergoing thrombolysis for management of peripheral arterial or venous thromboses, as well as for submassive pulmonary embolism, were included. We examined the relationships between PFLs during catheter-directed lysis and the incidence of major bleeding-that is significant hemorrhage requiring transfusion, intracranial hemorrhage, or hemorrhage requiring adjunctive procedures. We also examined the duration of lysis and total lytic agent dose received to assess for association with major bleeding.

RESULTS

A total of 438 patients underwent catheter-directed lysis from January 1, 2016 through August 21, 2021, with a major bleeding rate of 16%. Patients who experienced major bleeding were more likely to be older (P = 0.022), experience in-stent thrombosis (P = 0.041), or have thrombosis in a lower extremity vessel (P = 0.011). There was no association between the incidence of major bleeding and a nadir PFL of <150 mg/dL (P = 0.194). Those who experienced major bleeding complications had a significantly greater decrease in PFL from baseline to nadir. This was true for both absolute (P = 0.029) and relative (P = 0.034) PFL decrease. Only percent decrease remained a significant predictor when adjusting for age, thrombosis type, and thrombosis location (P = 0.041). The PFL changes that were the best predictors of major bleeding complications were an absolute decrease of 146 mg/dL, or a relative decrease of 47%, giving a sensitivity and specificity of 71% and 48%, respectively. If neither were true, the negative predictive value for major bleeding was 89% regardless of absolute PFL.

CONCLUSIONS

In this large, multicenter cohort, there does not appear to be an association between absolute PFL and major bleeding during catheter-directed lysis. Specifically, the typical absolute threshold of < 150 mg/dL was not an independent predictor of major bleeding. There was an association between percent-change in plasma fibrinogen and major bleeding, which aligns with the underlying physiologic mechanism of fibrinogen degradation coagulopathy. Applying a so-called "50-150 Rule" to catheter-directed lysis may decrease bleeding complications. That is, continued lysis should be re-evaluated if PFL drops by ≥150 mg/dL or by ≥50% from baseline regardless of absolute PFL.

Ultrasound-Assisted, Catheter-Directed Thrombolysis for Acute Intermediate/High-Risk Pulmonary Embolism: Design of the Multicenter USAT IH-PE Registry and Preliminary Results

Catheter-based revascularization procedures were developed as an alternative to systemic thrombolysis for patients with intermediate-high- and high-risk pulmonary embolisms. USAT IH-PE is a retrospective and prospective multicenter registry of such patients treated with ultrasound-facilitated, catheter-directed thrombolysis, whose preliminary results are presented in this study. The primary endpoint was the incidence of pulmonary hypertension (PH) at follow-up. Secondary endpoints were short- and mid-term changes in the echocardiographic parameters of right ventricle (RV) function, in-hospital and all-cause mortality, and procedure-related bleeding events. Between March 2018 and July 2023, 102 patients were included. The majority were at intermediate-high-risk PE (86%), were mostly female (57%), and had a mean age of 63.7 ± 14.5 years, and 28.4% had active cancer. Echocardiographic follow-up was available for 70 patients, and in only one, the diagnosis of PH was confirmed by right heart catheterization, resulting in an incidence of 1.43% (CI 95%, 0.036-7.7). RV echocardiographic parameters improved both at 24 h and at follow-up. In-hospital mortality was 3.9% (CI 95%, 1.08-9.74), while all-cause mortality was 11% (CI 95%, 5.4-19.2). Only 12% had bleeding complications, of whom 4.9% were BARC ≥ 3. Preliminary results from the USAT IH-PE registry showed a low incidence of PH, improvement in RV function, and a safe profile.

Risk Stratification and Management of Intermediate-Risk Acute Pulmonary Embolism

Pulmonary embolism (PE) is the third most common cause of cardiovascular death and necessitates prompt, accurate risk assessment at initial diagnosis to guide treatment and reduce associated mortality. Intermediate-risk PE, defined as the presence of right ventricular (RV) dysfunction in the absence of hemodynamic compromise, carries a significant risk for adverse clinical outcomes and represents a unique diagnostic challenge. While small clinical trials have evaluated advanced treatment strategies beyond standard anticoagulation, such as thrombolytic or endovascular therapy, there remains continued debate on the optimal care for this patient population. Here, we review the most recent risk stratification models, highlighting differences between prediction scores and their limitations, and discuss the utility of serologic biomarkers and imaging modalities to detect right ventricular dysfunction. Additionally, we examine current treatment recommendations including anticoagulation strategies, use of thrombolytics at full and reduced doses, and utilization of invasive treatment options. Current knowledge gaps and ongoing studies are highlighted.

Thrombolysis vs Anticoagulation: Unveiling the Trade-Offs in Massive Pulmonary Embolism

Massive pulmonary embolism (MPE) is a severe form of venous thromboembolism (VTE) wherein enormous blood clots block the pulmonary arteries, resulting in substantial illness and death. Even with the progress made in diagnostic methods and treatments, the most effective approach for managing MPE is still a topic of considerable discussion. This study examines the delicate equilibrium between thrombolysis and anticoagulation in managing the problematic clinical situation posed by MPE, elucidating the compromises linked to each strategy. The genesis of MPE lies in the pathophysiology of VTE, when blood clots that originate from deep veins in the lower legs or pelvis move to the pulmonary vasculature, leading to an abrupt blockage. This obstruction leads to a series of hemodynamic alterations, such as elevated pulmonary vascular resistance, strain on the right ventricle, and compromised cardiac output, finally resulting in cardiovascular collapse. The seriousness of MPE is commonly categorized according to hemodynamic stability, with significant cases presenting immediate risks to patient survival. Traditionally, heparin has been the primary approach to managing MPE to prevent the spread of blood clots and their movement to other parts of the body. Nevertheless, there have been ongoing discussions regarding the effectiveness of thrombolysis, which entails the immediate delivery of fibrinolytic drugs to remove the blood clot. The use of thrombolysis in managing MPE is being reconsidered because of concerns over bleeding complications and long-term results despite its capacity to resolve the blocking clot quickly. This review rigorously analyzes the current body of evidence, exploring the intricacies of thrombolysis and anticoagulation in MPE. The focus is on evaluating the risk-benefit balance of each treatment option, considering aspects such as the patient's other medical conditions, hemodynamic stability, and potential long-term consequences. This review aims to clarify the complexities of the thrombolysis versus anticoagulation dilemma. It seeks to provide clinicians, researchers, and policymakers with a thorough understanding of the trade-offs in managing MPE. The goal is to facilitate informed decision-making and enhance patient outcomes.

Ultrasound-Assisted Catheter-Directed Thrombolysis for the Management of Pulmonary Embolism: A Single Center Experience in a Community Hospital

Current guidelines recommend anticoagulation alone for low-risk pulmonary embolism (PE) with the addition of systemic thrombolysis for high-risk PE. However, treatment recommendations for intermediate-risk PE are not well-defined. Due to bleeding risks associated with systemic thrombolysis, ultrasound-assisted catheter-directed thrombolysis (USAT) has evolved as a promising treatment modality. USAT is thought to decrease the rate of major bleeding by using localized delivery with lower thrombolytic dosages. Currently, there is little guidance on the implementation of USAT in the real-world clinical setting. This study was designed to evaluate our experience with USAT at this single community hospital with a newly initiated Pulmonary Embolism Response Team (PERT). All patients identified by the PERT with an acute PE diagnosed by a computed tomography (CT) scan from January 2021 to January 2023 were included. During the study period, there were 89 PERT activations with 40 patients (1 high-risk and 37 intermediate-risk PE) receiving USAT with alteplase administered at a fixed rate of 1 mg/h per catheter for 6 h. The primary efficacy outcome was the change in Pulmonary Embolism Severity Index (PESI) score within 48 h after USAT. The primary safety outcome was major bleeding within 72 h. The mean age was 57.4 ± 17.4 years and 50% (n = 20) were male, 17.5% (n = 7) had active malignancy, and 20% (n = 8) had a history of prior deep vein thrombosis (DVT) or PE. The mean PESI score decreased from baseline to 48 h post-USAT (84.7 vs 74.9; p = 0.025) and there were no major bleeding events. The overall hospital length of stay was 7.5 ± 9.8 days and ICU length of stay was 2.2 ± 2.8 days. This study outlined our experience at this single community hospital which resulted in an improvement in PESI scores and no major bleeding events observed.

Catheter-directed thrombolysis guided by pulmonary artery pressure registration in pulmonary embolism: a case report

Background

Duration and dosage of thrombolysis for ultrasound-assisted catheter-directed thrombolysis (UACDT) in patients with intermediate high-risk pulmonary embolism remain controversial and treatment protocols vary.

Case summary

A 58-year-old female patient suffered from a right-sided urolithiasis. The clinical course was complicated by an intermediate high-risk pulmonary embolism [pulmonary embolism severity index (PESI) score 108 points and simplified PESI ≥1] with bilateral proximal thrombus and significant right heart dysfunction. The pulmonary embolism response team (PERT) made a decision towards UACDT. The standard duration of UACDT ranges between 6 and 15 h depending on clinical parameters. In this particular case, the clinical parameters such as heart rate (no tachycardia) or oxygen saturation (chronic obstructive pulmonary disease) might lead to premature termination of UACDT. Therefore, PERT decided to additionally monitor pulmonary artery pressure (PAP) continuously during the UACDT via a separate pigtail catheter in the pulmonary artery. Ultrasound-assisted catheter-directed thrombolysis was performed using 1 mg/h recombinant tissue plasminogen activator (rtPA) per catheter, while PAP was registered continuously. Heart rate and oxygen saturation remained unchanged during UACDT. However, after 6 h of UACDT, systolic PAP decreased slightly from 62 to 55 mmHg and therapy was prolonged to 15 h. Pulmonary artery pressure dropped to 46 mmHg after 15 h. The patient was discharged from hospital at Day 7, and echocardiography revealed no signs of right heart dysfunction.

Discussion

Dosage of the thrombolysis agent and duration of UACDT are still a matter of debate. Besides clinical parameters and transthoracic echocardiography, invasive real-time PAP monitoring during UACDT could facilitate important information for therapy guidance in selected cases.

Ultrasound-assisted catheter-directed thrombolysis in a patient with COVID-19 infection and bilateral intermediate-to-high-risk pulmonary embolism: a case report

Background

Acute pulmonary embolism (PE) is a common cardiovascular disorder, potentially associated with high morbidity and mortality rates.

Case summary

Herein, we report on a patient with COVID-19 infection and bilateral PE, who presented after cardiovascular resuscitation with return of spontaneous circulation. Initially, an acute coronary syndrome was suspected but bedside echocardiography showed dilatation of the right ventricle (RV) and RV dysfunction, helping to establish the diagnosis of acute intermediate-to-high-risk PE, which was subsequently confirmed by contrast-enhanced computed tomography pulmonary angiography. The patient was successfully treated using low-dose (12 mg of tissue plasminogen) ultrasound-assisted catheter-directed thrombolysis, which resulted in prompt clinical improvement and reversal of RV dysfunction without bleeding complications.

Discussion

This case demonstrates the importance of echocardiography for the differential diagnosis of PE and of catheter-directed thrombolysis for its treatment in patients with intermediate-to-high-risk and high-risk PEs.

Risk factors and treatment interventions associated with incomplete thrombus resolution and pulmonary hypertension after pulmonary embolism

BACKGROUND

Residual pulmonary vascular occlusion (RPVO) affects one half of patients after a pulmonary embolism (PE). The relationship between the risk factors and therapeutic interventions for the development of RPVO and chronic thromboembolic pulmonary hypertension is unknown.

METHODS

This retrospective review included PE patients within a 26-month period who had baseline and follow-up imaging studies (ie, computed tomography [CT], ventilation/perfusion scans, transthoracic echocardiography) available. We collected the incidence of RPVO, percentage of pulmonary artery occlusion (%PAO), baseline CT %PAO, most recent CT %PAO, and difference between the baseline and most recent %PAO on CT (Δ%PAO).

RESULTS

A total of 354 patients had imaging reports available; 197 with CT and 315 with transthoracic echocardiography. The median follow-up time was 144 days (interquartile range [IQR], 102-186 days). RPVO was present in 38.9% of the 354 patients. The median Δ%PAO was -10.0% (IQR, -32% to -1.2%). Fewer patients with a provoked PE developed RPVO (P ≤ .01), and the initial troponin level was lower in patients who developed RPVO (P = .03). The initial thrombus was larger in the patients who received advanced intervention vs anticoagulation (baseline CT %PAO: median, 61.2%; [IQR, 27.5%-75.0%] vs median, 12.5% [IQR, 2.5%-40.0%]; P ≤ .0001). Catheter-directed thrombolysis (CDT; median Δ%PAO, -47.5%; IQR, -63.7% to -8.7%) and surgical pulmonary embolectomy (SPE; median Δ%PAO, -42.5; IQR, -68.1% to -18.7%) had the largest thrombus reduction compared with anticoagulation (P = .01). Of the 354 patients, 76 developed pulmonary hypertension; however, only 14 received pulmonary hypertension medications and 12 underwent pulmonary thromboendarterectomy. Cancer (odds ratio [OR], 1.7) and planned prolonged anticoagulation (>1 year; OR, 2.20) increased the risk of RPVO. In contrast, the risk was lower for men (OR, 0.61), patients with recent surgery (OR, 0.33), and patients treated with SPE (OR, 0.42). A larger Δ%PAO was found in men (coefficient, -8.94), patients with a lower body mass index (coefficient, -0.66), patients treated with CDT (coefficient, -18.12), and patients treated with SPE (coefficient, -21.69). A lower Δ%PAO was found in African-American patients (coefficient, 7.31).

CONCLUSIONS

The use of CDT and SPE showed long-term benefit in thrombus reduction.

Large Saddle Pulmonary Embolism Safely Managed by Ultrasonic-supported Catheter-directed Thrombolytic Therapy

A 40-year-old patient confirmed on computed tomography of the pulmonary arteries (CT/PAs) a large saddle pulmonary embolus in the main PA extending in both branches. He was managed by ultrasound-supported catheter-directed (EkoSonic, Boston Scientific) intrapulmonary thrombolytic therapy using a recombinant tissue plasminogen activator prolonged infusion over 16 h with a total dose of 50 mg divided in both PAs simultaneously with intravenous unfractionated heparin. He showed clinical improvement with improved arterial oxygen (PaO2) with reduced oxygen therapy with a nasal cannula. Follow-up right heart catheterization showed a significant reduction of PA pressure from 96/32 (mean 64) to 47/27 (mean 39) mmHg. Repeat pulmonary angiography showed significant improvement in PA branch opacification, suggesting increased flow and successful therapy. The patient received oral anticoagulants for months. He had followed with CT/PA and echocardiogram after 4 weeks, both were normalized. He resumed his regular physical activities, including exercises in the gymnasium.

Mechanical Support Strategies for High-Risk Procedures in the Invasive Cardiac Catheterization Laboratory: A State-of-the-Art Review

Thanks to advancements in percutaneous cardiac interventions, an expanding patient population now qualifies for treatment through percutaneous endovascular procedures. High-risk interventions far exceed coronary interventions and include transcatheter aortic valve replacement, endovascular management of acute pulmonary embolism and ventricular tachycardia ablation. Given the frequent impairment of ventricular function in these patients, frequently deteriorating during percutaneous interventions, it is hypothesized that mechanical ventricular support may improve periprocedural survival and subsequently patient outcome. In this narrative review, we aimed to provide the relevant evidence found for the clinical use of percutaneous mechanical circulatory support (pMCS). We searched the Pubmed database for articles related to pMCS and to pMCS and invasive cath lab procedures. The articles and their references were evaluated for relevance. We provide an overview of the clinically relevant evidence for intra-aortic balloon pump, Impella, TandemHeart and ECMO and their role as pMCS in high-risk percutaneous coronary intervention, transcatheter valvular procedures, ablations and high-risk pulmonary embolism. We found that the right choice of periprocedural pMCS could provide a solution for the hemodynamic challenges during these procedures. However, to enhance the understanding of the safety and effectiveness of pMCS devices in an often high-risk population, more randomized research is needed.

High-Risk Pulmonary Embolism: Management for the Intensivist

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

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

BACKGROUND

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

METHODS

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

IMPLICATIONS

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

Acute and chronic venous occlusion

This review article provides an overview of acute and chronic venous occlusion, a condition that can cause significant morbidity and mortality if not diagnosed and treated promptly. The article begins with an introduction to the anatomy of the venous system, followed by a discussion of the causes and clinical features of venous occlusion. The diagnostic tools available for the assessment of venous occlusion, including imaging modalities such as ultrasound, CT, and MRI, are then discussed, along with their respective advantages and limitations. The article also covers the treatment options for acute and chronic venous occlusion, including anticoagulant therapy and endovascular interventions. This review aims to provide radiologists with an updated understanding of the pathophysiology, diagnosis, and management of acute and chronic venous occlusion.

FlowTriever System for Pulmonary Embolism: A Review of Clinical Evidence

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

Advanced Treatment of Hemodynamically Unstable Acute Pulmonary Embolism and Clinical Follow-up

High-risk acute pulmonary embolism (PE), defined as acute PE associated with hemodynamic instability, remains a significant contributor to cardiovascular morbidity and mortality in the United States and worldwide. Historically, anticoagulant therapy in addition to systemic thrombolysis has been the mainstays of medical therapy for the majority of patients with high-risk PE. In efforts to reduce the morbidity and mortality, a wide array of interventional and surgical therapies has been developed and employed in the management of these patients. However, the most recent guidelines for the management of PE have reserved the use of these advanced therapies in scenarios where thrombolytic therapy plus anticoagulation are unsuccessful. This is due largely to the lack of prospective, randomized studies in this population. Stemming from this, the approach to treatment of these patients varies widely depending on institutional experience and resources. Furthermore, morbidity and mortality remain unacceptably high in this population, with estimated 30-day mortality of at least 30%. As such, development of a standardized approach to treatment of these patients is paramount to improving outcomes. Early and accurate risk stratification in conjunction with a multidisciplinary team approach in the form of a PE response team is crucial. With the advent of novel therapies for the treatment of acute PE, in addition to the growing availability of and familiarity with mechanical circulatory support systems, such a standardized approach may now be within reach.

Right Ventricular Recovery: Early and Late Changes after Acute PE Diagnosis

Right ventricular (RV) failure is a critical cause of morbidity and mortality in patients presenting with pulmonary embolism (PE). The presentation of RV failure is based on the combination of clinical findings, laboratory abnormalities, and imaging evidence. An improved understanding of the pathophysiology of RV dysfunction following PE has given rise to more accurate risk stratification and broader therapeutic approaches. A subset of patients with PE develop chronic RV dysfunction with or without pulmonary hypertension. In this review, we focus on the impact of PE on the RV and its implications for risk stratification, prognosis, acute management, and long-term therapy.

Treatment of intracardiac thrombi using ultra-slow low-dose thrombolytic therapy: A case report

A 57-year-old male with previously known severe primary mitral regurgitation was admitted to the intensive care unit (ICU) due to massive venous thromboembolism, associated with right ventricular dysfunction and two large mobile right atrial thrombi. Due to deterioration in his clinical condition despite standard treatment with unfractionated heparin, it was decided to use an ultra-slow low-dose thrombolysis protocol, which consisted of a 24-hour infusion of 24 mg of alteplase at a rate of 1 mg per hour, without initial bolus. The treatment was continued for 48 consecutive hours, with clinical improvement and resolution of the intracardiac thrombi and no complications. One month after ICU admission, successful mitral valve repair surgery was conducted. This case demonstrates that ultra-slow low-dose thrombolysis is a valid bailout treatment option in patients with large intracardiac thrombi refractory to the standard approach.

A comparison of the efficacy and safety between anticoagulation alone and combined with catheter-directed thrombolysis for treatment of pulmonary embolism on outcome: A systematic review and meta-analysis

BACKGROUND

Catheter-directed thrombolysis (CDT) is one of the newest treatment options for submassive pulmonary embolism (sPE). This study will compare the efficacy and safety of catheter-directed thrombolysis (CDT) combine with anticoagulation versus anticoagulation alone (AC) in patients with PE.

METHODS

A database search was conducted using PubMed, EMBASE, Cochrane Library, and Clinicaltrials.gov for trials that compared CDT with AC in patients with pulmonary embolism. The primary outcomes was1-year mortality. The secondary outcomes were in-hospital, 30 days, 90 days mortality, in-hospital major and minor bleeding (Thrombolysis in Myocardial Infarction (TIMI) classification), length of hospital stay (LOS), reduction of pulmonary arterial systolic pressure (PASP) and RV/LV diameter ratio.

RESULTS

A total of 16 articles (3 RCTs and 13 non-RCTs) and 10595 patients were included in this study. 2237 patients were in the CDT group and 8358 patients were in the AC group. CDT group was associated with significantly lower in-hospital mortality (2.1% vs 6.2%,OR:0.36, 95%CI:0.26-0.51, p < .00001,I2 = 0%), 30 days mortality (3.1% vs 8.6%,OR:0.39,95%CI:0.23-0.66, p = .0005, I2 = 0%), 90 days mortality (3.8% vs 7.7%,OR:0.49,95%CI:0.29-0.80,p = .005,I2 = 7%), 1-year mortality (6.1% vs 11%, OR:0.51, 95%CI:0.35-0.76, p = .0008,I2 = 36%) compared to AC group, especially in ultrasound-assisted thrombolysis (USAT) subgroup. There were no differences on major bleeding between two groups (1.8% vs 2.2%, OR:1.10, 95%CI:0.61-1.98, p = .75, I2 = 0%). Minor bleeding was significantly higher in CDT group than AC group (6.2% vs 3.8%, OR:1.93,95%CI:1.27-2.94.66, p = .002, I2 = 1%). CDT group significantly reduced PASP (WMD:11.90,95%CI:6.45-17.35, p < .0001, I2 = 72%) and RV/LV (WMD:0.17,95%CI:0.04-0.30, p = .009, I2 = 69%) rapidly than AC group after treatment. LOS was similar between two groups (WMD:0.02,95%CI: -0.68-0.73, p = .95, I2 = 51%).

CONCLUSION

Results thus confirmed that CDT reduced in-hospital, 30 days, 90 days and 1-year all-cause mortality in patients with sPE compared to AC, particularly in USAT subgroup. Nonetheless, CDT group was associated with a higher risk of minor bleeding.

Time-based reperfusion in haemodynamically unstable pulmonary embolism patients: does early reperfusion therapy improve survival?

High-risk pulmonary embolism (PE) is associated with significant morbidity and mortality. Systemic thrombolysis remains the most evidenced-based treatment for haemodynamically unstable PE, but in daily clinical practice, it remains largely underused. In addition, unlike acute myocardial infarction or stroke, a clear time window for reperfusion therapy, including fibrinolysis, for high-risk PE has not been defined either for fibrinolysis or for the more recently incorporated options of catheter-based thrombolysis or thrombectomy. The aim of the present article is to review the current evidence supporting the potential benefit of earlier administration of reperfusion in haemodynamically unstable PE patients and suggest some potential strategies to further explore this issue.

Comparative Outcomes of Catheter-Directed Thrombolysis Plus Systemic Anticoagulation Versus Systemic Anticoagulation Alone in the Management of Intermediate-Risk Pulmonary Embolism in a Systematic Review and Meta-Analysis

There are limited and conflicting data on the initial management of intermediate-risk (or submassive) pulmonary embolism (PE). This study sought to compare the outcomes of catheter-directed thrombolysis (CDT) in combination with systemic anticoagulation (SA) to SA alone. A systematic search was conducted in MEDLINE, EMBASE, PubMed, and the Cochrane databases from inception to March 1, 2023 for studies comparing the outcomes of CDT + SA versus SA alone in intermediate-risk PE. The outcomes were in-hospital, 30-day, 90-day, and 1-year mortality; bleeding; blood transfusion; right ventricular recovery; and length of stay. Random-effects models was used to calculate the pooled incidence and risk ratios (RRs) with 95% confidence intervals (CIs). A total of 15 (2 randomized and 13 observational) studies with 10,549 (2,310 CDT + SA and 8,239 SA alone) patients were included. Compared with SA, CDT + SA was associated with significantly lower in-hospital mortality (RR 0.41, 95% CI 0.30 to 0.56, p <0.001), 30-day mortality (RR 0.34, 95% CI 0.18 to 0.67, p = 0.002), 90-day mortality (RR 0.34, 95% CI 0.17 to 0.67, p = 0.002), and 1-year mortality (RR 0.58, 95% CI 0.34 to 0.97, p = 0.04). There were no significant differences between the 2 cohorts in the rates of major bleeding (RR 1.39, 95% CI 0.72 to 2.68, p = 0.56), minor bleeding (RR 1.83, 95% CI 0.97 to 3.46, p = 0.06), and blood transfusion (RR 0.34, 95% CI 0.10 to 1.15, p = 0.08). In conclusion, CDT + SA is associated with significantly lower short-term and long-term all-cause mortality, without any differences in major/minor bleeding, in patients with intermediate-risk PE.