Low left ventricular outflow tract velocity time integral predicts normotensive shock in patients with acute pulmonary embolism.

In this study, we found that a low LVOT VTI (<15 cm), a simple bedside point-of-care measurement, predicts normotensive shock in patients with acute intermediate-risk PE.

Relationship Between the Mixed Venous-to-Arterial Carbon Dioxide Gradient and Cardiac Index in Acute Pulmonary Embolism.

BACKGROUND: Among patients with acute pulmonary embolism (PE) undergoing mechanical thrombectomy, the cardiac index (CI) is frequently reduced even among those without clinically apparent shock. The purpose of this study was to describe the mixed venous-to-arterial carbon dioxide gradient (CO2 gap), a surrogate of perfusion adequacy, among patients with acute PE undergoing mechanical thrombectomy. METHODS: This was a single-center retrospective study of consecutive patients with PE undergoing mechanical thrombectomy and simultaneous pulmonary artery catheterization over a 3-year period. RESULTS: Of 107 patients, 97 had simultaneous mixed venous and arterial blood gas measurements available. The CO2 gap was elevated (>6 mmHg) in 51% of the cohort and in 49% of patients with intermediate-risk PE. A reduced CI (≤2.2 L/min/m2) was associated with an increased odds (OR = 7.9; 95% CI 3.49-18.1, p < 0.001) for an elevated CO2 gap. There was an inverse relationship between CI and CO2 gap. For every 1 L/min/m2 decrease in the CI, the CO2 gap increased by 1.3 mmHg (p = 0.001). Among patients with an elevated baseline CO2 gap >6 mmHg, thrombectomy improved CO2 gap, CI, and mixed venous oxygen saturation. When the CO2 gap was dichotomized above and below 6, there was no difference in in-hospital mortality (9% vs. 0%; p = 0.10, HR: 1.24; 95% CI: 0.97-1.60; P = 0.085). CONCLUSIONS: Among patients with acute PE undergoing mechanical thrombectomy, the CO2 gap is abnormal in nearly 50% of patients and inversely related to CI. Further studies should examine the relationship between markers of perfusion and outcomes in this population to refine risk stratification.

Need for a Cardiogenic Shock Team Collaborative-Promoting a Team-Based Model of Care to Improve Outcomes and Identify Best Practices.

Cardiogenic shock continues to carry a high mortality rate despite contemporary care, with no breakthrough therapies shown to improve survival over the past few decades. It is a time-sensitive condition that commonly results in cardiovascular complications and multisystem organ failure, necessitating multidisciplinary expertise. Managing patients with cardiogenic shock remains challenging even in well-resourced settings, and an important subgroup of patients may require cardiac replacement therapy. As a result, the idea of leveraging the collective cognitive and procedural proficiencies of multiple providers in a collaborative, team-based approach to care (the "shock team") has been advocated by professional societies and implemented at select high-volume clinical centers. A slowly maturing evidence base has suggested that cardiogenic shock teams may improve patient outcomes. Although several registries exist that are beginning to inform care, particularly around therapeutic strategies of pharmacologic and mechanical circulatory support, none of these are currently focused on the shock team approach, multispecialty partnership, education, or process improvement. We propose the creation of a Cardiogenic Shock Team Collaborative-akin to the successful Pulmonary Embolism Response Team Consortium-with a goal to promote sharing of care protocols, education of stakeholders, and discovery of how process and performance may influence patient outcomes, quality, resource consumption, and costs of care.

Medical and Mechanical Circulatory Support of the Failing Right Ventricle.

PURPOSE OF REVIEW: To describe medical therapies and mechanical circulatory support devices used in the treatment of acute right ventricular failure. RECENT FINDINGS: Experts have proposed several algorithms providing a stepwise approach to medical optimization of acute right ventricular failure including tailored volume administration, ideal vasopressor selection to support coronary perfusion, inotropes to restore contractility, and pulmonary vasodilators to improve afterload. Studies have investigated various percutaneous and surgically implanted right ventricular assist devices in several clinical settings. The initial management of acute right ventricular failure is often guided by invasive hemodynamic data tracking parameters of circulatory function with the use of pharmacologic therapies. Percutaneous microaxial and centrifugal extracorporeal pumps bypass the failing RV and support circulatory function in severe cases of right ventricular failure.

The physiology of cardiac tamponade and implications for patient management.

Exceeding the limit of pericardial stretch, intrapericardial collections exert compression on the right heart and decrease preload. Compensatory mechanisms ensue to maintain hemodynamics in the face of a depressed stroke volume but are outstripped as disease progresses. When constrained within a pressurized pericardial space, the right and left ventricles exhibit differential filling mediated by changes in intrathoracic pressure. Invasive hemodynamics and echocardiographic findings inform on the physiologic effects. In this review, we describe tamponade physiology and implications for supportive care and effusion drainage.

The Latest in Resuscitation Research: Highlights From the 2022 American Heart Association's Resuscitation Science Symposium.

BACKGROUND: Every year the American Heart Association's Resuscitation Science Symposium (ReSS) brings together a community of international resuscitation science researchers focused on advancing cardiac arrest care. METHODS AND RESULTS: The American Heart Association's ReSS was held in Chicago, Illinois from November 4th to 6th, 2022. This annual narrative review summarizes ReSS programming, including awards, special sessions and scientific content organized by theme and plenary session. CONCLUSIONS: By exploring both the science of resuscitation and important related topics including survivorship, disparities, and community-focused programs, this meeting provided important resuscitation updates.

To PLEX or Not to PLEX for Amiodarone-Induced Thyrotoxicosis.

Amiodarone-induced thyrotoxicosis (AIT) carries significant cardiovascular morbidity. There are two types of AIT with treatment including antithyroid medications and corticosteroids and treatment of ventricular arrhythmias. Therapeutic plasma exchange (TPE) also known as "PLEX" may help remove thyroid hormones and amiodarone. We report a case of PLEX in an attempt to treat cardiogenic shock secondary to AIT. This case highlights the robust rapidly deleterious demise of AIT, specifically in patients with decompensated heart failure. The decision to PLEX or not to PLEX for AIT should be individualized, prior to definitive therapy.

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.

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.

Chronic thromboembolic pulmonary hypertension and the post-pulmonary embolism (PE) syndrome.

Over a third of patients surviving acute pulmonary embolism (PE) will experience long-term cardiopulmonary limitations. Persistent thrombi, impaired gas exchange, and altered hemodynamics account for aspects of the postpulmonary embolism syndrome that spans mild functional limitations to debilitating chronic thromboembolic pulmonary hypertension (CTEPH), the most worrisome long-term consequence. Though pulmonary endarterectomy is potentially curative for the latter, less is understood surrounding chronic thromboembolic disease (CTED) and post-PE dyspnea. Advances in pulmonary vasodilator therapies and growing expertise in balloon pulmonary angioplasty provide options for a large group of patients ineligible for surgery, or those with persistent postoperative pulmonary hypertension. In this clinical review, we discuss epidemiology and pathophysiology as well as advances in diagnostics and therapeutics surrounding the spectrum of disease that may follow months after acute PE.

Prevalence and Predictors of Cardiogenic Shock in Intermediate-Risk Pulmonary Embolism: Insights From the FLASH Registry.

BACKGROUND: Patients with acute pulmonary embolism (PE) and hypotension (high-risk PE) have high mortality. Cardiogenic shock can also occur in nonhypotensive or normotensive patients (intermediate-risk PE) but is less well characterized. OBJECTIVES: The authors sought to evaluate the prevalence and predictors of normotensive shock in intermediate-risk PE. METHODS: Intermediate-risk PE patients in the FLASH (FlowTriever All-Comer Registry for Patient Safety and Hemodynamics) registry undergoing mechanical thrombectomy with the FlowTriever System (Inari Medical) were included. The prevalence of normotensive shock (systolic blood pressure ≥90 mm Hg but cardiac index ≤2.2 L/min/m2) was assessed. A composite shock score consisting of markers of right ventricular function and ischemia (elevated troponin, elevated B-type natriuretic peptide, moderately/severely reduced right ventricular function), central thrombus burden (saddle PE), potential additional embolization (concomitant deep vein thrombosis), and cardiovascular compensation (tachycardia) was prespecified and assessed for its ability to identify normotensive shock patients. RESULTS: Over one-third of intermediate-risk PE patients in FLASH (131/384, 34.1%) were in normotensive shock. The normotensive shock prevalence was 0% in patients with a composite shock score of 0 and 58.3% in those with a score of 6 (highest score). A score of 6 was a significant predictor of normotensive shock (odds ratio: 5.84; 95% CI: 2.00-17.04). Patients showed significant on-table improvements in hemodynamics post-thrombectomy, including normalization of the cardiac index in 30.5% of normotensive shock patients. Right ventricular size, function, dyspnea, and quality of life significantly improved at the 30-day follow-up. CONCLUSIONS: Although hemodynamically stable, over one-third of intermediate-risk FLASH patients were in normotensive shock with a depressed cardiac index. A composite shock score effectively further risk stratified these patients. Mechanical thrombectomy improved hemodynamics and functional outcomes at the 30-day follow-up.

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

BACKGROUND: Evidence supporting interventional pulmonary embolism (PE) treatment is needed. AIMS: We aimed to evaluate the acute safety and effectiveness of mechanical thrombectomy for intermediate- and high-risk PE in a large real-world population. METHODS: FLASH is a multicentre, prospective registry enrolling up to 1,000 US and European PE patients treated with mechanical thrombectomy using the FlowTriever System. The primary safety endpoint is a major adverse event composite including device-related death and major bleeding at 48 hours, and intraprocedural adverse events. Acute mortality and 48-hour outcomes are reported. Multivariate regression analysed characteristics associated with pulmonary artery pressure and dyspnoea improvement. RESULTS: Among 800 patients in the full US cohort, 76.7% had intermediate-high risk PE, 7.9% had high-risk PE, and 32.1% had thrombolytic contraindications. Major adverse events occurred in 1.8% of patients. All-cause mortality was 0.3% at 48-hour follow-up and 0.8% at 30-day follow-up, with no device-related deaths. Immediate haemodynamic improvements included a 7.6 mmHg mean drop in mean pulmonary artery pressure (-23.0%; p<0.0001) and a 0.3 L/min/m2 mean increase in cardiac index (18.9%; p<0.0001) in patients with depressed baseline values. Most patients (62.6%) had no overnight intensive care unit stay post-procedure. At 48 hours, the echocardiographic right ventricle/left ventricle ratio decreased from 1.23±0.36 to 0.98±0.31 (p<0.0001 for paired values) and patients with severe dyspnoea decreased from 66.5% to 15.6% (p<0.0001).  Conclusions: Mechanical thrombectomy with the FlowTriever System demonstrates a favourable safety profile, improvements in haemodynamics and functional outcomes, and low 30-day mortality for intermediate- and high-risk PE.

Continuous mechanical aspiration thrombectomy performs equally well in main versus branch pulmonary emboli: A subgroup analysis of the EXTRACT-PE trial.

INTRODUCTION: The EXTRACT-PE trial evaluated the safety and performance of the Indigo Aspiration System (Penumbra Inc.) with an 8F continuous mechanical aspiration thrombectomy system for the treatment of pulmonary embolism (PE). This subgroup analysis evaluates performance outcomes of patients with main pulmonary artery (PA) emboli versus discrete unilateral or bilateral PA emboli without main PA involvement. METHODS: The EXTRACT-PE trial was a prospective, single-arm, multicenter trial that enrolled 119 patients with acute submassive PE. Emboli location was collected at the time of enrollment, CT obstruction was measured and assessed by a Core Lab, and patients were grouped on whether emboli involved the main PA (with or without branch vessels) or not (branch vessels alone). Procedural device time, changes in the right ventricle to left ventricle (RV/LV) ratio, and systolic PA pressure from pre-and posttreatment were compared between the two groups. RESULTS: Out of the 119 patients enrolled, 118 had core lab-assessed clot locations. Forty-five (38.1%) had emboli that involved the main PA and 73 (61.9%) had only branch emboli. No significant difference was observed between these groups for 30-day mortality, procedural device time, changes in RV/LV ratio, reduction in CT Obstruction Index, or for systolic PA pressure from pre-and posttreatment. The mean absolute reduction in clot burden was significant in both groups. CONCLUSION: Continuous mechanical aspiration thrombectomy with the 8F Indigo Aspiration System was effective at improving clinical outcomes for submassive PE patients regardless of emboli location, and clot burden was significantly reduced in both groups.

Histologic assessment of lower extremity deep vein thrombus from patients undergoing percutaneous mechanical thrombectomy.

BACKGROUND: Histologic analyses of deep vein thrombi (DVTs) have used autopsy samples and animal models. To the best of our knowledge, no previous study has reported on thrombus composition after percutaneous mechanical extraction. Because elements of chronicity and organization render thrombus resistant to anticoagulation and thrombolysis, a better understanding of clot evolution could inform therapy. METHODS: We performed a histologic evaluation of DVTs from consecutive patients who had undergone mechanical thrombectomy for extensive iliofemoral DVTs using the Clottriever/Flowtriever device (Inari Medical, Irvine, Calif). The DVTs were scored using a semiquantitative method according to the degree of fibrosis (collagen deposition on trichrome staining) and organization (endothelial growth with capillaries and fibroblastic penetration). RESULTS: Twenty-three specimens were available for analysis, with 20 presenting as acute DVT (≤14 days from symptom onset). Of the 23 patients, 11 (48%) had had >5% fibrosis (ie, collagen deposition) and 14 (61%) had had >5% organization (ie, endothelial growth, capillaries, fibroblasts). Four patients with acute DVT had had ≥25% organized thrombus and two had had ≥25% collagen deposition. Of the 20 patients with acute DVT, 40% had had >5% fibrosis and 55% had had >5% organization. The acuity of DVT did not correlate with the amount of fibrosis or organizing scores. CONCLUSIONS: A large proportion of patients with acute DVT will have histologic elements of chronicity and fibrosis. A better understanding of the relationship between such elements and the response to anticoagulant agents and fibrinolytic drugs could inform our approach to therapy.