Acute outcomes for the full US cohort of the FLASH mechanical thrombectomy registry in pulmonary embolism

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.

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.

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.

Aspiration of thrombus for intermediate-risk subacute pulmonary embolism

Pulmonary embolism is the most common cardiovascular disease after myocardial infarction and stroke. Konstantinides (Eur Heart J 41(4):543-603, 2020) Current guidelines categorize patients with PE as being at low, intermediate, and high risk of early death, with the intermediate-risk group experiencing the greatest uncertainty regarding treatment recommendations. Rapid reduction of the thrombus load by thrombolysis significantly reduces symptoms and decreases mortality, but is accompanied by a high risk of bleeding. Meyer (N Engl J Med 370(15):1402-11, 2014) Mechanical thrombectomy (CDTE) have been proven safe and efficient, yet current ESC guidelines suggest the utilization of catheter interventions only for hypotensive patients with high bleeding risk, failed systemic thrombolysis, and cardiogenic shock or if a patient does not respond to conservative therapy Konstantinides (Eur Heart J 41(4):543-603, 2020). Here, we report a case of an intermediate-risk patient with pulmonary embolism who underwent thrombus aspiration and showed significant improvement in symptoms after treatment.

Percutaneous mechanical thrombectomy in acute pulmonary embolism: Outcomes from a safety-net hospital

BACKGROUND

Our study aims to present clinical outcomes of mechanical thrombectomy (MT) in a safety-net hospital.

METHODS

This is a retrospective study of intermediate or high-risk pulmonary embolism (PE) patients who underwent MT between October 2020 and May 2023. The primary outcome was 30-day mortality.

RESULTS

Among 61 patients (mean age 57.6 years, 47% women, 57% Black) analyzed, 12 (19.7%) were classified as high-risk PE, and 49 (80.3%) were intermediate-risk PE. Of these patients, 62.3% had Medicaid or were uninsured, 50.8% lived in a high poverty zip code. The prevalence of normotensive shock in intermediate-risk PE patients was 62%. Immediate hemodynamic improvements included 7.4 mmHg mean drop in mean pulmonary artery pressure (-21.7%, p < 0.001) and 93% had normalization of their cardiac index postprocedure. Thirty-day mortality for the entire cohort was 5% (3 patients) and 0% when restricted to the intermediate-risk group. All 3 patients who died at 30 days presented with cardiac arrest. There were no differences in short-term mortality based on race, insurance type, citizenship status, or socioeconomic status. All-cause mortality at most recent follow up was 13.1% (mean follow up time of 13.4 ± 8.5 months).

CONCLUSION

We extend the findings from prior studies that MT demonstrates a favorable safety profile with immediate improvement in hemodynamics and a low 30-day mortality in patients with acute PE, holding true even with relatively higher risk and more vulnerable population within a safety-net hospital.

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.

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

Background and Aims

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

Methods

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

Results

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

Conclusion

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

Percutaneous interventions for pulmonary embolism

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

Effectiveness and Safety of Large-Bore Aspiration Thrombectomy for Intermediate- or High-Risk Pulmonary Embolism

PURPOSE

To evaluate effectiveness and safety of large-bore mechanical thrombectomy of intermediate- or high-risk pulmonary embolism (PE) and factors associated with effectiveness.

MATERIALS AND METHODS

A retrospective review of 257 patients with intermediate- or high-risk PE who underwent mechanical thrombectomy using the Flowtriever system (Inari Medical, Irvine, California) between July 2019 and November 2021 was conducted. Data were analyzed using the linear regression and Kaplan-Meier methods with a Type 1 error set at 0.05.

RESULTS

Patients' mean age was 62 years, and 51% were male. PE risk was classified as high, intermediate-high, and intermediate-low in 37 (14%), 201 (78%), and 18 (7%) of the patients, respectively. Procedural technical success was 100%. The mean pulmonary artery pressure (MPAP) decreased from a mean of 32 mmHg (SD ± 9) before to 24 mmHg (SD ± 9) after thrombectomy (mean decrease, 8 mmHg [SD ± 6]; P < .0001). Immediate complications occurred in 2% of the patients. Postprocedural 30-day and all-time PE-attributable mortality in a mean of 1.3-year follow-up was 2% and 6%, respectively. In multivariate analysis, the presence of lower extremity DVT at presentation (β ± SE, -7.60 ± 3.22; P = .019) and a higher prethrombectomy MPAP (β ± SE, -0.19 ± 0.04; P < .001) were associated with lower degrees of decrease in MPAP in the intermediate-high-risk PE group. Among 14 patients with postthrombectomy PE-attributable mortality, 13 had postthrombectomy MPAPs of >20 mmHg.

CONCLUSIONS

Large-bore aspiration thrombectomy is a safe and effective treatment for reducing PAP in patients with intermediate- or high-risk PE. Postthrombectomy MPAPs of >20 mmHg might indicate postthrombectomy PE-attributable mortality in high-risk patients.

Management of high and intermediate-high risk pulmonary embolism: A position paper of the Interventional Cardiology Working Group of the Italian Society of Cardiology

Pulmonary embolism (PE) is a potentially life-threatening condition that remains a major global health concern. Noteworthy, patients with high- and intermediate-high-risk PE pose unique challenges because they often display clinical and hemodynamic instability, thus requiring rapid intervention to mitigate the risk of clinical deterioration and death. Importantly, recovery from PE is associated with long-term complications such as recurrences, bleeding with oral anticoagulant treatment, pulmonary hypertension, and psychological distress. Several novel strategies to improve risk factor characterization and management of patients with PE have recently been introduced. Accordingly, this position paper of the Working Group of Interventional Cardiology of the Italian Society of Cardiology deals with the landscape of high- and intermediate-high risk PE, with a focus on bridging the gap between the evolving standards of care and the current clinical practice. Specifically, the growing importance of catheter-directed therapies as part of the therapeutic armamentarium is highlighted. These interventions have been shown to be effective strategies in unstable patients since they offer, as compared with thrombolysis, faster and more effective restoration of hemodynamic stability with a consistent reduction in the risk of bleeding. Evolving standards of care underscore the need for continuous re-assessment of patient risk stratification. To this end, a multidisciplinary approach is paramount in refining selection criteria to deliver the most effective treatment to patients with unstable hemodynamics. In conclusion, the current management of unstable patients with PE should prioritize tailored treatment in a patient-oriented approach in which transcatheter therapies play a central role.

In-Hospital versus Out-of-Hospital Pulmonary Embolism: Clinical Characteristics, Biochemical Markers and Echocardiographic Indices

BACKGROUND

A significant proportion of pulmonary embolisms (PEs) occurs in patients during hospitalisation for another reason. However, limited data regarding differences between out-of-hospital PE (OHPE) and in-hospital PE (IHPE) is available. We aimed to compare these groups regarding their clinical characteristics, biochemical markers, and echocardiographic indices.

METHODS

This was a prospective, single-arm, single-centre study. Adult consecutive patients with non-COVID-related PE from September 2019 to March 2022 were included and followed up for 12 months.

RESULTS

The study included 180 (84 women) patients, with 89 (49.4%) suffering from IHPE. IHPE patients were older, they more often had cancer, were diagnosed earlier after the onset of symptoms, they had less frequent pain and higher values of high sensitivity troponin I and brain natriuretic peptide levels compared to OHPE patients. Echocardiographic right ventricular (RV) dysfunction was detected in similar proportions in the 2 groups. IHPE had increased in-hospital mortality (14.6% vs. 3.3%, p = 0.008) and similar post-discharge to 12-month mortality with OHPE patients.

CONCLUSIONS

In this prospective cohort study, IHPE differed from OHPE patients regarding age, comorbidities, symptoms, and levels of biomarkers associated with RV dysfunction. IHPE patients had higher in-hospital mortality compared to OHPE patients and a similar risk of death after discharge.

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.

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.

Prospective Multicenter International Registry of Ultrasound-Facilitated Catheter-Directed Thrombolysis in Intermediate-High and High-Risk Pulmonary Embolism (KNOCOUT PE)

BACKGROUND

Prior clinical trials have demonstrated the efficacy of ultrasound-facilitated catheter-directed thrombolysis (USCDT) for the treatment of acute intermediate-risk pulmonary embolism (PE) using reduced thrombolytic doses and shorter infusion durations. However, utilization and safety of such strategies in broader PE populations remain unclear. The KNOCOUT PE (The EKoSoNic Registry of the Treatment and Clinical Outcomes of Patients With Pulmonary Embolism) registry is a multicenter international registry designed to study the treatment of acute PE with USCDT, with focus on safety outcomes.

METHODS

The KNOCOUT PE prospective cohort included 489 patients (64 sites internationally) with acute intermediate-high or high-risk PE treated with USCDT between March 2018 and June 2020. Principal safety outcomes were independently adjudicated International Society on Thrombosis and Haemostasis major bleeding at 72 hours post-treatment and mortality within 12 months of treatment. Additional outcomes included change in right ventricular/left ventricular ratio and quality of life measures over 12 months.

RESULTS

Mean alteplase (r-tPA [recombinant tissue-type plasminogen activator]) infusion duration was 10.5 hours. Mean total r-tPA dose was 18.1 mg, with 31.0% of patients receiving ≤12 mg. Major bleeding events within 72 hours occurred in 1.6% (8/489) of patients. One patient experienced worsening of a preexisting subdural hematoma after USCDT and therapeutic anticoagulation, which ultimately required surgery. All-cause mortality at 30 days was 1.0% (5/489). Improvement in PE quality of life score was observed with a 41.1% (243/489, 49.7%) and 44.2% (153/489, 31.3%) mean relative reduction by 3 and 12 months, respectively.

CONCLUSIONS

In a prospective observational cohort study of patients with intermediate-high and high-risk PE undergoing USCDT, mean r-tPA dose was 18 mg, and the rates of major bleeding and mortality were low.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03426124.

Catheter-directed therapy for acute pulmonary embolism: results of a multicenter national registry

INTRODUCTION AND OBJECTIVES

Catheter-directed therapy (CDT) for acute pulmonary embolism (PE) is an emerging therapy that combines heterogeneous techniques. The aim of the study was to provide a nationwide contemporary snapshot of clinical practice and CDT-related outcomes.

METHODS

This Investigator-initiated multicenter registry aimed to include consecutive patients with intermediate-high risk (IHR) or high-risk (HR), acute PE eligible for CDT. The primary outcome of the study was in-hospital all-cause death.

RESULTS

A total of 253 patients were included, of whom 93 (36.8%) had HR-PE, and 160 (63.2%) had IHR-PE with a mean age of 62.3±15.1 years. Local thrombolysis was performed in 70.8% and aspiration thrombectomy in 51.8%, with 23.3% of patients receiving both. However, aspiration thrombectomy was favored in the HR-PE cohort (80.6% vs 35%; P<.001). Only 51 patients (20.2%) underwent CDT with specific PE devices. The success rate for CDT was 90.9% (98.1% of IHR-PE patients vs 78.5% of HR-PE patients, P<.001). In-hospital mortality was 15.5%, and was highly concentrated in the HR-PE patients (37.6%) and significantly lower in IHR-PE patients (2.5%), P<.001. Long-term (24-month) mortality was 40.2% in HR-PE patients vs 8.2% in IHR-PE patients (P<.001).

CONCLUSIONS

Despite the high success rate for CDT, in-hospital mortality in HR-PE is still high (37.6%) compared with very low IHR-PE mortality (2.5%).

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.

Hemodialysis catheter-related right atrial thrombus treated with the FlowTriever system

Tunneled catheters are frequently used in patients with end-stage renal disease who require hemodialysis access. Catheter-related atrial thrombus is a documented complication of prolonged catheter use. The incidence of catheter-related atrial thrombus is 2% to 29%, with a high mortality rate approaching 20%, raising concerns for serious complications and death in the absence of an established universal management plan. This case series demonstrates the successful use of a minimally invasive approach to treat patients with intracardiac thrombus and high perioperative risk factors using mechanical and aspiration thrombectomy with the FlowTriever system (Inari Medical).

A nationwide analysis of reperfusion therapies for pulmonary embolism in older patients with frailty

BACKGROUND

Reperfusion therapy is challenging in the elderly. Catheter-directed therapies are an alternative for higher-risk pulmonary embolism (PE) patients if systemic thrombolysis (ST) is contraindicated or has failed. Their safety has not been evaluated in specific vulnerable populations.

AIMS

We aimed to assess the safety of reperfusion therapies in elderly and frail patients in the real world.

METHODS

In the US Nationwide Inpatient Sample from 2016 to 2020, we identified hospitalisations of patients ≥65 years with PE and defined a frailty subgroup using the Johns Hopkins Adjusted Clinical Groups frailty-defining diagnosis indicator. We investigated reperfusion therapies (ST, catheter-directed thrombolysis [CDT], catheter-based thrombectomy [CBT], surgical embolectomy [SE]) and their associated safety outcomes (overall and major bleeding).

RESULTS

Among 980,245 hospitalisations of patients ≥65 years with PE (28.0% frail), reperfusion therapies were used in 4.9% (17.6% among high-risk PE). ST utilisation remained stable, while the use of catheter-directed therapies increased from 1.7% in 2016 to 3.2% in 2020. Among all hospitalisations with reperfusion, CDT, compared to ST, was associated with reduced major bleeding (5.8% vs 12.2%, odds ratio [OR] 0.58, 95% confidence interval [CI]: 0.49-0.70); these results also applied to frail patients. CBT, compared to SE, was also associated with reduced major bleeding (11.0% vs 22.4%, OR 0.63, 95% CI: 0.43-0.91), but not among frail patients. These differences were particularly significant in patients with non-high-risk PE. Differences persisted for overall bleeding as well.

CONCLUSIONS

Catheter-directed therapies may be a safer alternative to classical reperfusion therapies for elderly and frail patients with PE requiring reperfusion treatment.

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.

Mechanical thrombectomy in intermediate- and high-risk acute pulmonary embolism: hemodynamic outcomes at three months

BACKGROUND

Mechanical thrombectomy has been shown to reduce thrombus burden and pulmonary artery pressure (PAP) and to improve right ventricular (RV) function in patients with high-risk or intermediate-high-risk pulmonary embolism (PE). As hemodynamic data after mechanical thrombectomy for PE are scarce, we aimed to assess the hemodynamic effects of mechanical thrombectomy in acute PE with right heart overload.

METHODS

In this prospective, open-label study, patients with acute symptomatic, computed tomography-documented PE with signs of right heart overload underwent mechanical thrombectomy using the FlowTriever System. Right heart catheterization was performed immediately before and after thrombectomy and after three months. Transthoracic echocardiography was performed before thrombectomy, discharge, and at three months. This analysis was done after 20 patients completed three months of follow-up.

RESULTS

Twenty-nine patients (34% female) underwent mechanical thrombectomy, of which 20 completed three months follow-up with right heart catheterization. Most patients were at high (17%) or intermediate-high (76%) risk and had bilateral PE (79%). Before thrombectomy, systolic PAP (sPAP) was severely elevated (mean 51.3 ± 11.6 mmHg). Mean sPAP dropped by -15.0 mmHg (95% confidence interval [CI]: -18.9 to -11.0; p < 0.001) immediately after the procedure and continued to decrease from post-thrombectomy to three months (-6.4 mmHg, 95% CI: -10-0 to -2.9; p = 0.002). RV/left ventricular (LV) ratio immediately reduced within two days by -0.37 (95% CI: -0.47 to -0.27; p < 0.001). The proportion of patients with a tricuspid annular plane systolic excursion (TAPSE)/sPAP ratio < 0.31 mm/mmHg decreased from 28% at baseline to 0% before discharge and at three months (p = 0.007). There were no procedure-related major adverse events.

CONCLUSIONS

Mechanical thrombectomy for acute PE was safe and immediately reduced PAP and improved right heart function. The reduction in PAP was maintained at three months follow-up.

Interventional therapies for pulmonary embolism

Pulmonary embolism (PE) is the leading cause of in-hospital death and the third most frequent cause of cardiovascular death. The clinical presentation of PE is variable, and choosing the appropriate treatment for individual patients can be challenging. Traditionally, treatment of PE has involved a choice of anticoagulation, thrombolysis or surgery; however, a range of percutaneous interventional technologies have been developed that are under investigation in patients with intermediate-high-risk or high-risk PE. These interventional technologies include catheter-directed thrombolysis (with or without ultrasound assistance), aspiration thrombectomy and combinations of the aforementioned principles. These interventional treatment options might lead to a more rapid improvement in right ventricular function and pulmonary and/or systemic haemodynamics in particular patients. However, evidence from randomized controlled trials on the safety and efficacy of these interventions compared with conservative therapies is lacking. In this Review, we discuss the underlying pathophysiology of PE, provide assistance with decision-making on patient selection and critically appraise the available clinical evidence on interventional, catheter-based approaches for PE treatment. Finally, we discuss future perspectives and unmet needs.

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.

Current Insights for Catheter-Directed Therapies in Acute Pulmonary Embolism: Systematic Review and Our Single-Center Experience

In this review, the current status of the worldwide experience on different catheter-directed treatment systems utilized as alternative reperfusion methods in acute pulmonary-embolism was evaluated, and the risk stratification algorithms in which catheter-directed treatments may be implemented, source of evidence in this setting, adjudication of benefits and risks of available techniques, and innovative multidisciplinary frameworks for referral patterns and care delivery were discussed. Moreover, our perspectives on risk-based catheter-directed treatment utilization strategies in acute pulmonary embolism were summarized.

Catheter-directed mechanical aspiration thrombectomy in a real-world pulmonary embolism population: a multicenter registry

AIMS

High- (HR) and intermediate-high risk (IHR) pulmonary embolisms (PEs) are related to high early mortality and long-term sequelae. We aimed to describe clinical outcomes and adverse events in IHR and HR pulmonary embolism (PE) treated with catheter-directed mechanical thrombectomy (CDMT) in a real-world population.

METHODS AND RESULTS

This study is a multicenter, prospective registry enrolling 110 PE patients treated with CDMT between 2019 and 2022. The CDMT was performed using the 8F Indigo (Penumbra, Alameda, CA, USA) system bilaterally in pulmonary arteries (PAs). The primary safety endpoints included device or PE-related death during the 48-h after CDMT, procedure-related major bleeding, or other major adverse events. Secondary safety outcomes were all-cause mortality during hospitalization or the follow-up. The primary efficacy outcomes were the reduction of PA pressures and change in the right-to-left ventricular (RV/L) ratio assessed in the imaging 24-48 h after the CDMT.71.8% of patients had IHR PE and 28.2% HR PE. 11.8% of patients had a failure and 34.5% had contraindications to thrombolysis, and 2.7% had polytrauma. There was 0.9% intraprocedural death related to RV failure and 5.5% deaths within the first 48 h. CDMT was complicated by major bleeding in 1.8%, pulmonary artery injury in 1.8%, and ischaemic stroke in 0.9%. Immediate haemodynamic improvements included a 10.4 ± 7.8 mmHg (19.7%) drop in systolic PAP (P < 0.0001), a 6.1 ± 4.2 mmHg (18.8%) drop in mean PAP, and 0.48 ± 0.4 (36%) drop in RV/LV ratio (P < 0.0001).

CONCLUSION

These observational findings suggest that CDMT may improve hemodynamics with an acceptable safety profile in patients with IHR and HR PE.

ST-Segment Elevation: An Unexpected Culprit

The clinical presentation of pulmonary embolism (PE) and acute coronary syndrome can be similar. We report a case of a patient presenting with antero-septal ST-segment elevation after cardiac arrest, found to have acute-PE-mimicking ST-segment elevation myocardial infarction (STEMI), treated with aspiration thrombectomy and catheter-directed thrombolysis (CDT). A 78-year-old man was admitted with dyspnea, chest pain and tachycardia. During evaluation, cardiac arrest in pulseless electrical activity was documented. Advanced life support was started immediately. ECG post-ROSC revealed ST-segment elevation in V1-V4 and aVR. Echocardiography showed normal left ventricular function but right ventricular (RV) dilation and severe dysfunction. The patient was in shock and was promptly referred to cardiac catheterization that excluded significant CAD. Due to the discordant ECG and echocardiogram findings, acute PE was suspected, and immediate invasive pulmonary angiography revealed bilateral massive pulmonary embolism. Successful aspiration thrombectomy was performed followed by local alteplase infusion. At the end of the procedure, mPAP was reduced and blood pressure normalized allowing withdrawal of vasopressor support. Twenty-four-hour echocardiographic reassessment showed normal-sized cardiac chambers with preserved biventricular systolic function. Bedside echocardiography in patients with ST-segment elevation post-ROSC is instrumental in raising the suspicion of acute PE. In the absence of a culprit coronary lesion, prompt pulmonary angiography should be considered if immediately feasible. In these cases, CDT and aspiration in high-risk acute PE seem safe and effective in relieving obstructive shock and restoring hemodynamics.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Catheter-directed mechanical thrombectomy in a patient with high-risk pulmonary embolism complicated by out-of-hospital cardiac arrest: a case report

Background

Pulmonary embolism (PE) is common, and it is the third leading cause of cardiovascular death. The management of patients with high-risk PE generally consists of systemic thrombolysis; however, surgical or catheter-directed treatment (CDT) can be considered in selected cases.

Case summary

A 78-year-old female patient presenting with acute severe dyspnoea develops out-of-hospital cardiac arrest (OHCA). She was admitted with return of spontaneous circulation and a critical haemodynamic state upon arrival to the catheterization laboratory with an estimated no-flow time of 1 min and low-flow time of 52 min. An acute pulmonary angiogram reveals massive PE. After a PE response team conference, the patient was not found eligible for extracorporeal membrane oxygenation, surgery, or thrombolysis. The patient was treated with catheter-directed mechanical thrombectomy 129 min after first medical contact. The patient recovered and was discharged without any neurological deficits.

Discussion

Catheter-directed mechanical thrombectomy was a successful treatment in a patient with OHCA secondary to high-risk PE, where thrombolysis and surgical interventions were considered contraindicated. This case underlines the future perspectives of CDT and also that a multidisciplinary team approach may benefit patients with high-risk PE.

First use of large-bore suction thrombectomy for acute pulmonary embolism in Asia-Pacific: feasibility and short-term clinical outcomes

Clinical outcomes for intermediate or high-risk pulmonary emboli (PE) remain sub-optimal, with limited improvements in survival for the past 15 years. Anticoagulation alone results in slow thrombus resolution, persistent right ventricular (RV) dysfunction, patients remaining at risk of haemodynamic decompensation and increased likelihood of incomplete recovery. Thrombolysis elevates risk of major bleeding and is thus reserved for high-risk PE. Thus, a huge clinical need exists for an effective technique to restore pulmonary perfusion with minimal risk and avoidance of lytic therapy. In 2021, large bore suction thrombectomy (ST) was introduced in Asia for the first time and this study assessed the feasibility and short-term outcomes of Asian patients undergoing ST for acute PE. 40 consecutive patients (58% male, mean age of 58.3 ± 16.6 years) with intermediate (87.5%) or high-risk PE (12.5%) were enrolled in this prospective registry. 20% had prior VTE, 42.5% had contraindications to thrombolysis, and 10% failed to respond to thrombolysis. PE was idiopathic in 40%, associated with active cancer in 15% and post-operative status in 12.5%. Procedural time was 124 ± 30 min. Emboli were aspirated in all patients without the need for thrombolytics, resulting in a 21.4% reduction in mean pulmonary arterial pressures and 123% increase TASPE-PASP ratio, a prognostic measure of RV-arterial coupling. (both p < 0.001) Procedural complications were 5% and 87.5% patients survived to discharge without symptomatic VTE recurrence during 184 days of mean follow-up. ST affords an effective reperfusion option for PE without thrombolytics, normalises RV overload and provides excellent short-term clinical outcomes.

Percutaneous Management of High-Risk Pulmonary Embolism

Acute pulmonary embolism (PE) leads to an abrupt increase in pulmonary vascular resistance and right ventricular afterload, and when significant enough, can result in hemodynamic instability. High-risk PE is a dire cardiovascular emergency and portends a poor prognosis. Traditional therapeutic options to rapidly reduce thrombus burden like systemic thrombolysis and surgical pulmonary endarterectomy have limitations, both with regards to appropriate candidates and efficacy, and have limited data demonstrating their benefit in high-risk PE. There are growing percutaneous treatment options for acute PE that include both localized thrombolysis and mechanical embolectomy. Data for such therapies with high-risk PE are currently limited. However, given the limitations, there is an opportunity to improve outcomes, with percutaneous treatments options offering new mechanisms for clot reduction with a possible improved safety profile compared with systemic thrombolysis. Additionally, mechanical circulatory support options allow for complementary treatment for patients with persistent instability, allowing for a bridge to more definitive treatment options. As more data develop, a shift toward a percutaneous approach with mechanical circulatory support may become a preferred option for the management of high-risk PE at tertiary care centers.