Low left ventricular outflow tract velocity time integral is associated with poor outcomes in acute pulmonary embolism

Right Ventricular-Pulmonary Arterial Uncoupling as a Predictor of Invasive Hemodynamics and Normotensive Shock in Acute Pulmonary Embolism

Right ventricular-pulmonary arterial coupling describes the relation between right ventricular contractility and its afterload and is estimated as the ratio of the tricuspid annular plane systolic excursion (TAPSE) to pulmonary arterial systolic pressure (PASP) by way of echocardiography. Whether TAPSE/PASP is reflective of invasive hemodynamics or occult shock in acute pulmonary embolism (PE) is unknown. This was a single-center retrospective study over a 3-year period of consecutive patients with PE who underwent mechanical thrombectomy and simultaneous pulmonary artery catheterization with echocardiograms performed within 24 hours before the procedure. A total of 70 patients (81% intermediate risk) had complete invasive hemodynamic profiles and echocardiograms, with TAPSE/PASP calculated. The optimal cutoff for TAPSE/PASP as a predictor of a reduced cardiac index (CI) (CI ≤2.2 L/min/m2) was 0.34 mm/mm Hg, with an area under the curve of 0.97 and sensitivity, specificity, positive predictive value, and negative predictive value of 97.3%, 90.9%, 92.3%, and 96.8%, respectively. Every 0.1 mm/mm Hg decrease in TAPSE/PASP was associated with a 0.24-L/min/m2 decrease in the CI. This relation was similar when restricted to intermediate-risk PE. The TAPSE/PASP ratio was predictive of normotensive shock with an odds ratio of 2.63 (95% confidence interval 1.42 to 4.76, p = 0.002) per unit decrease in the ratio. In conclusion, in patients with acute PE who underwent mechanical thrombectomy, TAPSE/PASP was a strong predictor of a reduced CI and normotensive shock. This means that noninvasive point-of-care assessment of hemodynamics may have added value in PE risk stratification.

Critical Care Management of Acute Pulmonary Embolism

The unprimed right ventricle is exquisitely sensitive to acute elevations in afterload. High pulmonary vascular tone incurred with acute pulmonary embolism has the potential to induce obstructive shock and circulatory collapse. While emergent pulmonary reperfusion is essential in severe circumstances, an important subset of pulmonary embolism patients may exhibit a less extreme presentation posing a management dilemma. As intensive care therapies have the potential to both salvage and harm the failing right ventricle, a keen understanding of the pathophysiology is requisite in the care of the contemporary patient with hemodynamically significant pulmonary embolism. Here, we review right ventricular pathophysiology, an approach to risk stratification, and offer guidance on the medical and mechanical supportive and therapeutic strategies for the critically ill patient with acute pulmonary embolism.

Inferior vena cava contrast reflux grade is associated with a reduced cardiac index in acute pulmonary embolism

BACKGROUND AND AIMS

Patients with intermediate-risk pulmonary embolism (PE) commonly present with a significantly reduced cardiac index (CI). However, the identification of this more severe profile requires invasive hemodynamic monitoring. Whether inferior vena cava (IVC) contrast reflux, as a marker of worse right ventricular function, can predict invasive hemodynamics has not been explored.

METHODS

This was a single-center retrospective study over a 3-year period of consecutive patients with PE undergoing mechanical thrombectomy and simultaneous pulmonary artery catheterization. CT pulmonary angiograms were reviewed, and contrast reflux was graded as no/minimal reflux (limited to the IVC) or substantial (opacification including hepatic veins) based on an established scale.

RESULTS

Substantial contrast reflux was present in 29 of 85 patients (34 %) and associated with a lower CI (1.8 ± 0.4 L/min/m2 v. 2.6 ± 1.0 L/min/m2, p < 0.001), higher pulmonary artery systolic pressure (53.2 ± 19.5 mmHg v. 44.0 ± 12.1 mmHg, p = 0.025), and worse right ventricular systolic function. An IVC contrast reflux grade > 3 was a significant predictor for a CI ≤2.2 L/min/m2 (OR: 22.5, 95 % CI: 4.8, 104.4, p < 0.001). Sensitivity, specificity, positive predictive value, and negative predictive value for substantial contrast reflux for a CI ≤2.2 L/min/m2 were 62.6 %, 93.1 %, 94.6 %, and 56.2 %, respectively. These findings remained significant in a multivariable model and were similar when isolating for intermediate-risk patients (n = 72, 85 %).

CONCLUSIONS

The degree of contrast reflux is highly specific for a reduced cardiac index in PE even when isolating for intermediate-risk patients. Real-time prediction of a hemodynamic profile may have added value in the risk-stratification of PE.

Composite Pulmonary Embolism Shock Score and Risk of Adverse Outcomes in Patients With Pulmonary Embolism

BACKGROUND

In hemodynamically stable patients with acute pulmonary embolism (PE), the Composite Pulmonary Embolism Shock (CPES) score predicts normotensive shock. However, it is unknown if CPES predicts adverse clinical outcomes. The objective of this study was to determine whether the CPES score predicts in-hospital mortality, resuscitated cardiac arrest, or hemodynamic deterioration.

METHODS

Patients with acute intermediate-risk PE admitted from October 2016 to July 2019 were included. CPES was calculated for each patient. The primary outcome was a composite of in-hospital mortality, resuscitated cardiac arrest, or hemodynamic decompensation. Secondary outcomes included individual components of the primary outcome. The association of CPES with primary and secondary outcomes was evaluated.

RESULTS

Among the 207 patients with intermediate-risk PE (64.7% with intermediate-high risk PE), 29 (14%) patients had a primary outcome event. In a multivariable model, a higher CPES score was associated with a worse primary composite outcome (adjusted hazard ratio [aHR], 1.81 [95% CI, 1.29-2.54]; P=0.001). Moreover, a higher CPES score predicted death (aHR, 1.76 [95% CI, 1.04-2.96]; P=0.033), resuscitated cardiac arrest (aHR, 1.99 [95% CI, 1.17-3.38]; P=0.011), and hemodynamic decompensation (aHR, 1.96 [95% CI, 1.34-2.89]; P=0.001). A high CPES score (≥3) was associated with the worse primary outcome when compared with patients with a low CPES score (22% versus 2.4%; P=0.003; aHR, 6.48 [95% CI, 1.49-28.04]; P=0.012). CPES score provided incremental prognostic value for the prediction of primary outcome over baseline demographics and European Society of Cardiology intermediate-risk subcategories (global Χ2 value increased from 0.63 to 1.39 to 13.69; P=0.005).

CONCLUSIONS

In patients with acute intermediate-risk PE, the CPES score effectively risk stratifies and prognosticates patients for the prediction of clinical events and provides incremental value over baseline demographics and European Society of Cardiology intermediate-risk subcategories.

Left atrial function index and left atrial electromechanical functions in anxiety disorders

BACKGROUND

There is a close linkage between anxiety disorders (ADs), and development of cardiovascular disease (CVD) and atrial fibrillation (AF). We aimed to investigate left atrial function index (LAFI) and its components, LA mechanical functions and atrial conduction times in AD patients and age- and gender-matched control group patients for the first time in the literature.

METHODS

A total of 48 AD patients and 33 healthy subjects were enrolled to the study prospectively. Echocardiographic parameters including two-dimensional conventional echocardiography, diastolic functions, LA mechanical functions, LAFI, atrial conduction times and atrial electromechanical delay (AEMD) were calculated.

RESULTS

The velocity-time integral of the LV outflow tract (LVOT-VTI), LAFI and LA conduit volume were significantly lower in AD patients. Atrial electromechanical coupling as established from lateral mitral annulus (PA lateral) was significantly higher in AD group than control group. Inter-AEMD and left intra-AEMD were also higher in AD group compared to control group. Age, gender, body surface area (BSA), conduit volume, LVOT-VTI and LAFI were significant factors associated with AD in univariate analysis. However, only BSA and LVOT-VTI (Odds ratio [OR]: 0.79, 95 CI%: 0.66-0.95, p = 0.013) were independently associated with AD in multivariate analysis. Age, gender, conduit volume and LAFI (OR: 0.25, 95 CI%: 0.03-2.12, p = 0.204) were not found to be independent associates of AD.

CONCLUSION

LAFI is impaired in patients suffering from AD compared to their age- and gender-matched counterparts but this impairment originates from lower levels of LVOT-VTI calculations in AD patients. Thus, LVOT-VTI, but not LAFI, is independently associated with AD.

Relationship between the mixed venous-to-arterial carbon dioxide gradient and the cardiac index in acute pulmonary embolism

AIMS

Among patients with acute pulmonary embolism (PE) undergoing mechanical thrombectomy, the cardiac index (CI) is frequently reduced even among those without a clinically apparent shock. The purpose of this study is 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 AND RESULTS

This was a single-centre retrospective study of consecutive patients with PE undergoing mechanical thrombectomy and simultaneous pulmonary artery catheterization over a 3-year period. 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 [odds ratio = 7.9; 95% confidence interval (CI) 3.49-18.1, P < 0.001] for an elevated CO2 gap. There was an inverse relationship between the CI and the 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 the CO2 gap, CI, and mixed venous oxygen saturation. When the CO2 gap was dichotomized above and below 6, there was no difference in the in-hospital mortality rate (9 vs. 0%; P = 0.10; hazard ratio: 1.24; 95% CI 0.97-1.60; P = 0.085).

CONCLUSION

Among patients with acute PE undergoing mechanical thrombectomy, the CO2 gap is abnormal in nearly 50% of patients and inversely related to the CI. Further studies should examine the relationship between markers of perfusion and outcomes in this population to refine risk stratification.

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.

Saddle Pulmonary Embolism Detected by Transthoracic Echocardiography in a Patient With Suspected Myocardial Infarction

•PE is very rarely identified on TTE. •Saddle PE does not represent a higher-risk subset of PE. •Catheter-based therapies are becoming more commonplace in the management of acute PE.

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.

Echocardiographic Evaluation of Pulmonary Embolism: A Review

Pulmonary embolism (PE) is the third most common cause of cardiovascular death in the United States. Appropriate risk stratification is an important component of the initial evaluation for acute management of these patients. Echocardiography plays a crucial role in the risk stratification of patients with PE. In this literature review, we describe the current strategies in risk stratification of patients with PE using echocardiography and the role of echocardiography in the diagnosis of PE.

Indigo® Aspiration System for thrombectomy in pulmonary embolism

Anticoagulation is mainstay therapy for patients with acute pulmonary embolism while systemic thrombolysis is reserved for those with hemodynamic instability. Over the last decade, percutaneous interventional options have entered the landscape aimed to achieve rapid pharmacomechanical pulmonary artery recanalization. The Penumbra Indigo® Aspiration System (Penumbra Inc., CA, USA) is a US FDA-approved large-bore aspiration thrombectomy device for the treatment of pulmonary embolism. Recent data has demonstrated improved radiographic end points with low rates of major adverse events in cases of intermediate-risk pulmonary embolism. In this review article, we outline device technology, applications, evidence and future directions.

Prognostic value of echocardiography-derived right ventricular dysfunction in haemodynamically stable pulmonary embolism: a systematic review and meta-analysis

BACKGROUND

We sought to determine the prognostic value of transthoracic echocardiography (TTE)-derived right ventricular dysfunction (RVD) in haemodynamically stable and intermediate-risk patients with acute pulmonary embolism (PE), evaluate continuous RVD parameters, and assess the literature quality.

METHODS

We searched MEDLINE, Embase and the Cochrane Central Register of Controlled Trials for studies assessing TTE-derived RVD in haemodynamically stable PE that reported in-hospital adverse events within 30 days. We determined pooled odds ratios (ORs) using a random-effects model, created funnel plots, evaluated the Newcastle-Ottawa scale and performed Grading of Recommendations, Assessment, Development and Evaluation.

RESULTS

Based on 55 studies (17 090 patients, 37.8% RVD), RVD was associated with combined adverse events (AEs) (OR 3.29, 95% confidence interval (CI) 2.59-4.18), mortality (OR 2.00, CI 1.66-2.40) and PE-related mortality (OR 4.01, CI 2.79-5.78). In intermediate-risk patients, RVD was associated with AEs (OR 1.99, CI 1.17-3.37) and PE-related mortality (OR 6.16, CI 1.33-28.40), but not mortality (OR 1.63, CI 0.76-3.48). Continuous RVD parameters provide a greater spectrum of risk compared to categorical RVD. We identified publication bias, poor methodological quality in 34/55 studies and overall low certainty of evidence.

CONCLUSIONS

RVD is frequent in PE and associated with adverse outcomes. However, data quality and publication bias are limitations of existing evidence.

Does the right ventricle size influence the left ventricle size and function in children with Ebstein anomaly?

PURPOSE

Patients with Ebstein anomaly (EA) have a variety of clinical manifestation. The assessment of structural and geometric characteristics of the heart is important for optimal management.

METHODS

We retrospectively analyzed echocardiography database from 2009 to 2020. We evaluate patients in two groups: patients with EA were in Group 1 and children without cardiovascular pathology were in Group 2. All children in both groups underwent echocardiography according to American Society of Echocardiography recommendations. The shape of the heart chambers and their function were studied in both groups.

RESULTS

There were 153 in Group 1 and 2000 children without cardiovascular disease in Group 2. It was shown that in children with EA, the shape of the ventricle became less spherical, which was accompanied by a decrease in myocardial mass, and the ejection fraction was reduced 34% of patients. The functional volume (non-atrialized part) of the right ventricle in patients with EA was reduced, and its contractility was preserved in 62% of cases. Preservation of the contractile properties of the right ventricle in most cases was associated with higher systolic pressure in its cavity.

CONCLUSION

TAPSE, TESV, and the velocity of the annulus fibrous ring movement according to tissue dopplerography in patients with EA do not allow us to assess the contractility of the right ventricle. The myocardial performance index (MPI) characterizes a decrease in the functional volume of the right ventricle.

Doppler-derived haemodynamics performed during admission echocardiography predict in-hospital mortality in cardiac intensive care unit patients

AIMS

Cardiac point-of-care ultrasound (CV-POCUS) has become a fundamental part for the assessment of patients admitted to cardiac intensive care units (CICU). We sought to refine the practice of CV-POCUS by identifying 2D and Doppler-derived measurements from bedside transthoracic echocardiograms (TTEs) performed in the CICU that are associated with mortality.

METHODS AND RESULTS

We retrospectively included Mayo Clinic CICU patients admitted from 2007 to 2018 and assessed the TTEs performed within 1 day of CICU admission, including Doppler and 2D measurements of left and right ventricular function. Logistic regression and classification and regression tree (CART) analysis were used to determine the association between TTE variables with in-hospital mortality. A total of 6957 patients were included with a mean age of 68.0 ± 14.9 years (37.0% females). A total of 609 (8.8%) patients died in the hospital. Inpatient deaths group had worse biventricular systolic function [left ventricular ejection fraction (LVEF) 48.2 ± 16.0% vs. 38.7 ± 18.2%, P < 0.0001], higher filling pressures, and lower forward flow. The strongest TTE predictors of hospital mortality were left ventricular outflow tract velocity-time integral [LVOT VTI, adjusted OR 0.912 per 1 cm higher, 95% confidence interval (CI) 0.883-0.942, P < 0.0001] followed by medial mitral E/e' ratio (adjusted OR 1.024 per 1 unit higher, 95% CI 1.010-1.039, P = 0.0011). Classification and regression tree analysis identified LVOT VTI <16 cm as the most important TTE predictor of mortality.

CONCLUSIONS

Doppler-derived haemodynamic TTE parameters have a strong association with mortality in the CICU, particularly LVOT VTI <16 cm or mitral E/e' ratio >15. The incorporation of these simplified Doppler-derived haemodynamics into admission CV-POCUS facilitates early risk stratification and strengthens the clinical yield of the ultrasound exam.

Left Ventricle Outflow Tract Velocity-Time Index and Right Ventricle to Left Ventricle Ratio as Predictors for in Hospital Outcome in Intermediate-Risk Pulmonary Embolism

Accurate estimation of risk with both imaging and biochemical parameters in intermediate risk pulmonary embolism (PE) remains challenging. The aim of the study was to evaluate echocardiographic parameters that reflect right and left heart hemodynamic as predictors of adverse events in intermediate risk PE. This was a retrospective observational study on patients with computed tomography pulmonary angiography diagnosis of PE admitted at Cardiology department of the Clinical Emergency Hospital of Oradea, Romania between January 2018—December 2021. Echocardiographic parameters obtained at admission were studied as predictors of in hospital adverse events. The following adverse outcomes were registered: death, resuscitated cardiac arrest, hemodynamic deterioration and need of rescue thrombolysis. An adverse outcome was present in 50 patients (12.62%). PE related death was registered in 17 patients (4.3%), resuscitated cardiac arrest occurred in 6 patients (1.51%). Another 20 patients (5.05%) required escalation of therapy with thrombolysis and 7 (1.76%) patients developed haemodynamic instability. Echocardiographic independent predictors for in hospital adverse outcome were RV/LV ≥ 1 (HR = 3.599, 95% CI 1.378−9.400, p = 0.009) and VTI ≤ 15 mm (HR = 11.711, 95% CI 4.336−31.633, p < 0.001). The receiver operator curve renders an area under curve for LVOT VTI ≤ 15 mm of 0.792 (95% CI 0.719−0.864, p < 0.001) and for a RV/LV ≥ 1 of 0.746 (95% CI 0.671−0.821, p < 0.001). A combined criterion (LVOT VTI ≤ 15 and RV/LV ≥ 1) showed a positive predictive value of 75% and a negative predictive value of 95% regarding in hospital adverse outcomes. Low LVOT VTI and increased RV/LV are useful for identifying normotensive patients with PE at risk for short term adverse outcomes. Combining an LVOT VTI ≤ 15 cm with a RV/LV ≥ 1 can identify with increased accuracy PE patients with impending risk of clinical deterioration.

Risk Stratification in Patients with Acute Pulmonary Embolism: Current Evidence and Perspectives

Risk stratification is one of the cornerstones of the management of acute pulmonary embolism (PE) and determines the choice of both diagnostic and therapeutic strategies. The first step is the identification of patent circulatory failure, as it is associated with a high risk of immediate mortality and requires a rapid diagnosis and prompt reperfusion. The second step is the estimation of 30-day mortality based on clinical parameters (e.g., original and simplified version of the pulmonary embolism severity index): low-risk patients without right ventricular dysfunction are safely managed with ambulatory anticoagulation. The remaining group of hemodynamically stable patients, labeled intermediate-risk PE, requires hospital admission, even if most of them will heal without complications. In recent decades, efforts have been made to identify a subgroup of patients at an increased risk of adverse outcomes (intermediate-high-risk PE), who might benefit from a more aggressive approach, including reperfusion therapies and admission to a monitored unit. The cur-rent approach, combining markers of right ventricular dysfunction and myocardial injury, has an insufficient positive predictive value to guide primary thrombolysis. Sensitive markers of circulatory failure, such as plasma lactate, have shown interesting prognostic accuracy and may play a central role in the future. Furthermore, the improved security of reduced-dose thrombolysis may enlarge the indication of this treatment to selected intermediate–high-risk PE.

Simultaneous Pulmonary Artery Pressure and Left Ventricle Stroke Volume Assessment Predicts Adverse Events in Patients With Pulmonary Embolism

Background

Certain echocardiographic parameters may serve as early predictors of adverse events in patients with hemodynamically compromising pulmonary embolism (PE).

Methods and Results

An observational analysis was conducted for patients with acute pulmonary embolism evaluated by a Pulmonary Embolism Response Team (PERT) between 2014 and 2020. The performance of clinical prediction algorithms including the Pulmonary Embolism Severity Index and Carl Bova score were compared using a ratio of right ventricle and left ventricle hemodynamics by dividing the pulmonary artery systolic pressure by the left ventricle stroke volume. The primary outcome of in‐hospital mortality, cardiac arrest, and the need for advanced therapies was evaluated by univariate and multivariable analyses. Of the 343 patients meeting the inclusion criteria, 215 had complete data. Pulmonary artery systolic pressure/left ventricle stroke volume was a clear predictor of the primary end point (odds ratio [OR], 2.31; P=0.005), performing as well or better than the Pulmonary Embolism Severity Index (OR, 1.43; P=0.06) or the Bova score (OR, 1.28; P=0.01).

Conclusions

This study is the first study to demonstrate the utility of early pulmonary artery systolic pressure/left ventricle stroke volume in predicting adverse clinical events in patients with acute pulmonary embolism. Pulmonary artery systolic pressure/left ventricle stroke volume may be a surrogate marker of ventricular asynchrony in high‐risk pulmonary embolism and should be prognostically evaluated.

Critical Care Echocardiography: A Primer for the Nephrologist

Critical care echocardiography (CCE) refers to the goal-directed use of transthoracic or transesophageal echocardiography and represents one of the most common applications of critical care ultrasound. CCE can be performed at the point of care, is easily repeated following changes in clinical status, and does not expose the patient to ionizing radiation. Nephrologists who participate in the care of patients in the intensive care unit will regularly encounter CCE as part of the decision-making and bedside management of ICU patients. The four primary indications for CCE are the characterization of shock, evaluation of preload tolerance, evaluation of volume responsiveness, and serial hemodynamic assessment to evaluate response to therapeutic interventions. This article provides an overview of the anatomical structures that are routinely assessed in basic CCE, describes how these findings are incorporated into the clinical assessment of critically ill patients, and introduces some common applications of advanced CCE.

Evaluating the Right Ventricle in Acute and Chronic Pulmonary Embolism: Current and Future Considerations

The right ventricle (RV), due to its morphologic and physiologic differences, is susceptible to sudden increase in RV afterload, as noted in patients with acute pulmonary embolism (PE). Functional impairment of RV function is a stronger presage of adverse outcomes in acute PE than the location or burden of emboli. While current iterations of most clinical prognostic scores do not incorporate RV dysfunction, advancements in imaging have enabled more granular and accurate assessment of RV dysfunction in acute PE. RV enlargement and dysfunction on imaging is noted only in a subset of patients with acute PE and is dependent on underlying cardiopulmonary reserve and clot burden. Specific signs like McConnell's and "60/60" sign are noted in less than 20% of patients with acute PE. About 2% of patients with acute PE develop chronic thromboembolic pulmonary hypertension, characterized by continued deterioration in RV function in a subset of patients with a continuum of RV function from preserved to overt right heart failure. Advances in molecular and other imaging will help better characterize RV dysfunction in this population and evaluate the response to therapies.

Relationship of left ventricular outflow tract velocity time integral to treatment strategy in submassive and massive pulmonary embolism

Pulmonary embolism is associated with high rates of mortality and morbidity. It is important to understand direct comparisons of current interventions to differentiate favorable outcomes and complications. The objective of this study was to compare ultrasound-accelerated thrombolysis versus systemic thrombolysis versus anticoagulation alone and their effect on left ventricular outflow tract velocity time integral. This was a retrospective cohort study of subjects ≥18 years of age with a diagnosis of submassive or massive pulmonary embolism. The primary outcome was the percent change in left ventricular outflow tract velocity time integral between pre- and post-treatment echocardiograms. Ultrasound-accelerated thrombolysis compared to anticoagulation had a greater improvement in left ventricular outflow tract velocity time integral, measured by percent change. No significant change was noted between the ultrasound-accelerated thrombolysis and systemic thrombolysis nor systemic thrombolysis and anticoagulation groups. Pulmonary artery systolic pressure only showed a significant reduction in the ultrasound-accelerated thrombolysis versus anticoagulation group. The percent change of right ventricular to left ventricular ratios was improved when systemic thrombolysis was compared to both ultrasound-accelerated thrombolysis and anticoagulation. In this retrospective study of submassive or massive pulmonary embolisms, left ventricular outflow tract velocity time integral demonstrated greater improvement in patients treated with ultrasound-accelerated thrombolysis as compared to anticoagulation alone, a finding not seen with systemic thrombolysis. While this improvement in left ventricular outflow tract velocity time integral parallels the trend seen in mortality outcomes across the three groups, it only correlates with changes seen in pulmonary artery systolic pressure, not in other markers of echocardiographic right ventricular dysfunction (tricuspid annular plane systolic excursion and right ventricular to left ventricular ratios). Changes in left ventricular outflow tract velocity time integral, rather than echocardiographic markers of right ventricular dysfunction, may be considered a more useful prognostic marker of both dysfunction and improvement after reperfusion therapy.

Difficulties of Managing Submassive and Massive Pulmonary Embolism in the Era of COVID-19

Acute pulmonary embolism (PE) is a potentially life-threatening manifestation of venous thromboembolic disease. Severe acute respiratory syndrome-coronavirus-2, a novel coronavirus that causes coronavirus disease-2019 (COVID-19), has been associated with an increased risk of thrombosis. We describe the therapeutic challenges of 3 patients presenting with PE and suspected or confirmed COVID-19. (Level of Difficulty: Beginner.).

Rationale for using the velocity-time integral and the minute distance for assessing the stroke volume and cardiac output in point-of-care settings

Background

Stroke volume (SV) and cardiac output (CO) are basic hemodynamic parameters which aid in targeting organ perfusion and oxygen delivery in critically ill patients with hemodynamic instability. While there are several methods for obtaining this data, the use of transthoracic echocardiography (TTE) is gaining acceptance among intensivists and emergency physicians. With TTE, there are several points that practitioners should consider to make estimations of the SV/CO as simplest as possible and avoid confounders.

Main body

With TTE, the SV is usually obtained as the product of the left ventricular outflow tract (LVOT) cross-sectional area (CSA) by the LVOT velocity–time integral (LVOT VTI); the CO results as the product of the SV and the heart rate (HR). However, there are important drawbacks, especially when obtaining the LVOT CSA and thus the impaction in the calculated SV and CO. Given that the LVOT CSA is constant, any change in the SV and CO is highly dependent on variations in the LVOT VTI; the HR contributes to CO as well. Therefore, the LVOT VTI aids in monitoring the SV without the need to calculate the LVOT CSA; the minute distance (i.e., SV × HR) aids in monitoring the CO. This approach is useful for ongoing assessment of the CO status and the patient’s response to interventions, such as fluid challenges or inotropic stimulation. When the LVOT VTI is not accurate or cannot be obtained, the mitral valve or right ventricular outflow tract VTI can also be used in the same fashion as LVOT VTI. Besides its pivotal role in hemodynamic monitoring, the LVOT VTI has been shown to predict outcomes in selected populations, such as in patients with acute decompensated HF and pulmonary embolism, where a low LVOT VTI is associated with a worse prognosis.

Conclusion

The VTI and minute distance are simple, feasible and reproducible measurements to serially track the SV and CO and thus their high value in the hemodynamic monitoring of critically ill patients in point-of-care settings. In addition, the LVOT VTI is able to predict outcomes in selected populations.