Right ventricular heart failure from pulmonary embolism: key distinctions from chronic pulmonary hypertension

Pulmonary Embolism and Right Ventricular Dysfunction: Mechanism and Management

Pulmonary embolism (PE) occurs when thrombi from deep vein thrombosis dislodge and obstruct pulmonary arteries, raising pulmonary artery pressure and straining the right ventricle. This strain can lead to right ventricular dysfunction (RVD), characterized by reduced cardiac output, impaired contractility, and potential development of chronic thromboembolic pulmonary hypertension. Clinically, PE may present with symptoms such as dyspnea, pleuritic chest pain, and tachycardia. Diagnosis is typically confirmed through computed tomography pulmonary angiography, biomarkers like D-dimer and cardiac troponins, and clinical scoring systems. Acute management focuses on hemodynamic support, including intravenous fluids and vasopressors, and may involve anticoagulation with low-molecular-weight heparin or direct oral anticoagulants. Severe cases may require systemic anticoagulation, catheter-directed techniques, and surgeries like pulmonary endarterectomy. Long-term management involves continued anticoagulation tailored to individual risk factors, with ongoing monitoring to prevent recurrence. Effective early diagnosis and management are crucial, as severe PE can significantly increase mortality and lead to serious complications. This review explores the pathophysiology, diagnosis, and management of PE and RVD.

Medical Emergencies in Pulmonary Hypertension

The management of acute medical emergencies in patients with pulmonary hypertension (PH) can be challenging. Patients with preexisting PH can rapidly deteriorate due to right ventricular decompensation when faced with acute physiological challenges that would usually be considered low-risk scenarios. This review considers the assessment and management of acute medical emergencies in patients with PH, encompassing both pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH), acknowledging these comprise the more severe groups of PH. Management protocols are described in a systems-based approach. Respiratory emergencies include pulmonary embolism, airways disease, and pneumonia; cardiac emergencies including arrhythmia and chest pain with acute myocardial infarction are discussed, alongside PH-specific emergencies such as pulmonary artery dissection and extrinsic coronary artery compression by a dilated proximal pulmonary artery. Other emergencies including sepsis, severe gastroenteritis with dehydration, syncope, and liver failure are also considered. We propose management recommendations for medical emergencies based on available evidence, international guidelines, and expert consensus. We aim to provide advice to the specialist alongside the generalist, and emergency doctors, nurses, and acute physicians in nonspecialist centers. A multidisciplinary team approach is essential in the management of patients with PH, and communication with local and specialist PH centers is paramount. Close hemodynamic monitoring during medical emergencies in patients with preexisting PH is vital, with early referral to critical care recommended given the frequent deterioration and high mortality in this setting.

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

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

Left atrium volume and ventricular volume ratio algorithm as indication of pulmonary hypertension etiology

BACKGROUND

Pressure overload of the right heart (pulmonary hypertension [PH]) can be an acute or a chronic process with various pathophysiologic changes affecting the dimensions of the heart chambers. The automatic four-chamber volumetric analysis tool is now available to measure the volume of the cardiac chambers in patients undergoing a computed tomography pulmonary angiogram (CTPA).

PURPOSE

To characterize the volumetric changes that occurred in response to increased systolic pulmonary arterial pressures (sPAP) in acute events, such as acute pulmonary embolism (APE), compared with other etiologies.

MATERIAL AND METHODS

Consecutive patients who underwent CTPA and echocardiography within 24 h between 2011 and 2015 were included. Differences in cardiac chamber volumes were investigated in correlation to the patients' sPAP.

RESULTS

The final cohort of 961 patients included 221 (23%) patients diagnosed with APE. The right (RV) to left (LV) ventricular volume ratio (VVR) was higher, while the left atrial (LA) volume index was smaller (P < 0.001) in the patients with APE. A decision tree for the prediction of APE showed that an RV to left VVR >2.8 was characteristic of APE, whereas an LA volume index >37.5 mL/m² was more compatible with PH due to other etiologies (P < 0.001).

CONCLUSION

The combination of VVR and LA volume index may help in differentiating between APE and chronic PH. CTPA-based volumetric information may be used to help clarify the underlying etiology of the dyspnea.

Myocardial extracellular volume assessment at CT in hospitalized COVID-19 patients with regards to pulmonary embolism

Purpose

To evaluate myocardial status through the assessment of extracellular volume (ECV) calculated at computed tomography (CT) in patients hospitalized for novel coronavirus disease (COVID-19), with regards to the presence of pulmonary embolism (PE) as a risk factor for cardiac dysfunction.

Method

Hospitalized patients with COVID-19 who underwent contrast-enhanced CT at our institution were retrospectively included in this study and grouped with regards to the presence of PE. Unenhanced and portal venous phase scans were used to calculate ECV by placing regions of interest in the myocardial septum and left ventricular blood pool. ECV values were compared between patients with and without PE, and correlations between ECV values and clinical or technical variables were subsequently appraised.

Results

Ninety-four patients were included, 63/94 of whom males (67%), with a median age of 70 (IQR 56−76 years); 28/94 (30%) patients presented with PE. Patients with PE had a higher myocardial ECV than those without (33.5%, IQR 29.4−37.5% versus 29.8%, IQR 25.1−34.0%; p = 0.010). There were no correlations between ECV and patients’ age (p = 0.870) or sex (p = 0.122), unenhanced scan voltage (p = 0.822), portal phase scan voltage (p = 0.631), overall radiation dose (p = 0.569), portal phase scan timing (p = 0.460), and contrast agent dose (p = 0.563).

Conclusions

CT-derived ECV could help identify COVID-19 patients at higher risk of cardiac dysfunction, especially when related to PE, to potentially plan a dedicated, patient-tailored clinical approach.

An Update on the Diagnosis and Management of Acute Right Heart Failure

Right ventricular (RV) dysfunction and resultant acute right heart failure (ARHF) is a rapidly growing field of interest, driven by increasing appreciation of its contribution to heart failure morbidity and mortality. Understanding of ARHF pathophysiology has advanced dramatically over recent years and can be broadly described as RV dysfunction related to acute changes in RV afterload, contractility, preload, or left ventricular dysfunction. There are several diagnostic clinical signs and symptoms as well as imaging and hemodynamic assessments that can provide insight into the degree of RV dysfunction. Medical management is tailored to the different causative pathologies, and in cases of severe or end-stage dysfunction, mechanical circulatory support can be utilized. In this review, we describe the pathophysiology of ARHF, how its diagnosis is established by clinical signs and symptoms and imaging findings, and provide an overview of treatment options, both medical and mechanical.

Perioperative cardiovascular pathophysiology in patients undergoing lung resection surgery: a narrative review

Although thoracic surgery is understood to confer a high risk of postoperative respiratory complications, the substantial haemodynamic challenges posed are less well appreciated. This review highlights the influence of cardiovascular comorbidity on outcome, reviews the complex pathophysiological changes inherent in one-lung ventilation and lung resection, and examines their influence on cardiovascular complications and postoperative functional limitation. There is now good evidence for the presence of right ventricular dysfunction postoperatively, a finding that persists to at least 3 months. This dysfunction results from increased right ventricular afterload occurring both intraoperatively and persisting postoperatively. Although many patients adapt well, those with reduced right ventricular contractile reserve and reduced pulmonary vascular flow reserve might struggle. Postoperative right ventricular dysfunction has been implicated in the aetiology of postoperative atrial fibrillation and perioperative myocardial injury, both common cardiovascular complications which are increasingly being appreciated to have impact long into the postoperative period. In response to the physiological demands of critical illness or exercise, contractile reserve, flow reserve, or both can be overwhelmed resulting in acute decompensation or impaired long-term functional capacity. Aiding adaptation to the unique perioperative physiology seen in patients undergoing thoracic surgery could provide a novel therapeutic avenue to prevent cardiovascular complications and improve long-term functional capacity after surgery.

Detection of pulmonary embolism severity using clinical characteristics, hematological indices, and machine learning techniques

Introduction

Pulmonary embolism (PE) is a cardiopulmonary condition that can be fatal. PE can lead to sudden cardiovascular collapse and is potentially life-threatening, necessitating risk classification to modify therapy following the diagnosis of PE. We collected clinical characteristics, routine blood data, and arterial blood gas analysis data from all 139 patients.

Methods

Combining these data, this paper proposes a PE risk stratified prediction framework based on machine learning technology. An improved algorithm is proposed by adding sobol sequence and black hole mechanism to the cuckoo search algorithm (CS), called SBCS. Based on the coupling of the enhanced algorithm and the kernel extreme learning machine (KELM), a prediction framework is also proposed.

Results

To confirm the overall performance of SBCS, we run benchmark function experiments in this work. The results demonstrate that SBCS has great convergence accuracy and speed. Then, tests based on seven open data sets are carried out in this study to verify the performance of SBCS on the feature selection problem. To further demonstrate the usefulness and applicability of the SBCS-KELM framework, this paper conducts aided diagnosis experiments on PE data collected from the hospital.

Discussion

The experiment findings show that the indicators chosen, such as syncope, systolic blood pressure (SBP), oxygen saturation (SaO2%), white blood cell (WBC), neutrophil percentage (NEUT%), and others, are crucial for the feature selection approach presented in this study to assess the severity of PE. The classification results reveal that the prediction model's accuracy is 99.26% and its sensitivity is 98.57%. It is expected to become a new and accurate method to distinguish the severity of PE.

Management of High-Risk Pulmonary Embolism: What Is the Place of Extracorporeal Membrane Oxygenation?

Pulmonary embolism (PE) is a common disease with an annual incidence rate ranging from 39-115 per 100,000 inhabitants. It is one of the leading causes of cardiovascular mortality in the USA and Europe. While the clinical presentation and severity may vary, it is a life-threatening condition in its most severe form, defined as high-risk or massive PE. Therapeutic options in high-risk PE are limited. Current guidelines recommend the use of systemic thrombolytic therapy as first-line therapy (Level Ib). However, this treatment has important drawbacks including bleeding complications, limited efficacy in patients with recurrent PE or cardiac arrest, and formal contraindications. In this context, the use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) in the management of high-risk PE has increased worldwide in the last decade. Strategies, including VA-ECMO as a stand-alone therapy or as a bridge to alternative reperfusion therapies, are associated with acceptable outcomes, especially if implemented before cardiac arrest. Nonetheless, the level of evidence supporting ECMO and alternative reperfusion therapies is low. The optimal management of high-risk PE patients will remain controversial until the realization of a prospective randomized trial comparing those cited strategies to systemic thrombolysis.

Thromboembolic complications of COVID-19: the combined effect of a pro-coagulant pattern and an endothelial thrombo-inflammatory syndrome

Coronavirus disease 2019 (COVID-19) is a newly emerging human infectious disease that has quickly become a worldwide threat to health, mainly causing severe acute respiratory syndrome. In addition to the widely described respiratory syndrome, COVID-19 may cause life-treating complications directly or indirectly related to this infection. Among these, thrombotic complications have emerged as an important issue in patients with COVID-19 infection, particularly in patients in intensive care units. Thrombotic complications due to COVID-19 are likely to occur due to a pro-coagulant pattern encountered in some of these patients or to a progressive endothelial thrombo-inflammatory syndrome causing microvascular disease. In the present authors' experience, from five different hospitals in Italy and the UK, imaging has proved its utility in identifying these COVID-19-related thrombotic complications, with translational clinical relevance. The aim of this review is to illustrate thromboembolic complications directly or indirectly related to COVID-19 disease. Specifically, this review will show complications related to thromboembolism due to a pro-coagulant pattern from those likely related to an endothelial thrombo-inflammatory syndrome.

Impella RP in hemodynamically unstable patients with acute pulmonary embolism

Over the last years, different case reports/studies have demonstrated that in patients with acute pulmonary embolism (PE) and refractory shock mechanical circulatory support (MCS) with Impella RP^® (Abiomed, Inc, Danvers, Mass) increases the chances of survival, significantly unloading the right ventricle and improving both the cardiac output and the mean pulmonary artery pressure. We reviewed the medical literature about the use of Impella RP in patients with acute PE and refractory shock using PubMed (MEDLINE), Scopus, Cochrane library, and Google Scholar databases. The final research was conducted in July 2019. The results evidenced that available data are currently scant to definitively assess the real role Impella RP^® in patient with acute PE and refractory shock. However, preliminary data seems to be very promising. Further larger studies are needed to confirm the safety and efficacy of MCS in these patients. A multidisciplinary assessment, using the PERT team, must be performed case by case to determine the need of MCS.

Liver disease and heart failure

INTRODUCTION

Several systemic conditions, inflammatory disease, infections and alcoholism, may affect both the heart and the liver. Common conditions, such as the non-alcoholic fatty liver disease (NAFLD), may increase the risk of cardiac dysfunction. Patients with acute decompensated HF (ADHF) may develop acute ischemic hepatitis and, chronic HF patients may develop congestive hepatopathy (CH).

EVIDENCE ACQUISITION

Laboratory anomalies of hepatic function may predict the outcome of patients with advanced HF and the evaluation of both cardiac and hepatic function is very important in the management of these patients. In clinically apparent ischemic hepatitis more than 90% of patients have some right-sided HF. There are systemic disorders characterized by the accumulation of metals or by metabolism defects that may affect primarily the liver but also the heart leading to symptomatic hypertrophic cardiomyopathy (HCM).

EVIDENCE SYNTHESIS

Abnormal LFTs indicate the mechanism of liver injury: liver congestion or liver ischemia. In AHF, it's important an adequate evaluation of heart and liver function in order to choose the treatment in order to ensure stable hemodynamic as well as optimal liver function.

CONCLUSIONS

Measurements of LFTs should be recommended in the early phase of ADHF management. Physicians with interest in HF should be trained in the evaluation of LFTs. It's very important for cardiologists to know the systemic diseases affecting both heart and liver and the first imaging or laboratory findings useful for a diagnosis. it is very important for internists, nephrologists, cardiologists, primary physicians and any physicians with interest in treating HF to recognize such signs and symptoms belong to rare diseases and liver diseases that could be mistaken for HF.

Oxidative Stress and Its Implications in the Right Ventricular Remodeling Secondary to Pulmonary Hypertension

Pulmonary hypertension (PH) is a pulmonary vascular disease characterized by increased pulmonary artery pressures. Long standing pulmonary arterial pressure overload leads to right ventricular (RV) hypertrophy, RV failure, and death. RV failure is a major determinant of survival in PH. Oxidative stress has been associated with the development of RV failure secondary to PH. Here we summarize the structural and functional changes in the RV in response to sustained pulmonary arterial pressure overload. Furthermore, we review the pre-clinical and clinical studies highlighting the association of oxidative stress with pulmonary vasculature and RV remodeling in chronic PH. Targeting oxidative stress promises to be an effective therapeutic strategy for the treatment of RV failure.

Assessment of Right Ventricular Function in the Research Setting: Knowledge Gaps and Pathways Forward. An Official American Thoracic Society Research Statement

BACKGROUND

Right ventricular (RV) adaptation to acute and chronic pulmonary hypertensive syndromes is a significant determinant of short- and long-term outcomes. Although remarkable progress has been made in the understanding of RV function and failure since the meeting of the NIH Working Group on Cellular and Molecular Mechanisms of Right Heart Failure in 2005, significant gaps remain at many levels in the understanding of cellular and molecular mechanisms of RV responses to pressure and volume overload, in the validation of diagnostic modalities, and in the development of evidence-based therapies.

METHODS

A multidisciplinary working group of 20 international experts from the American Thoracic Society Assemblies on Pulmonary Circulation and Critical Care, as well as external content experts, reviewed the literature, identified important knowledge gaps, and provided recommendations.

RESULTS

This document reviews the knowledge in the field of RV failure, identifies and prioritizes the most pertinent research gaps, and provides a prioritized pathway for addressing these preclinical and clinical questions. The group identified knowledge gaps and research opportunities in three major topic areas: 1) optimizing the methodology to assess RV function in acute and chronic conditions in preclinical models, human studies, and clinical trials; 2) analyzing advanced RV hemodynamic parameters at rest and in response to exercise; and 3) deciphering the underlying molecular and pathogenic mechanisms of RV function and failure in diverse pulmonary hypertension syndromes.

CONCLUSIONS

This statement provides a roadmap to further advance the state of knowledge, with the ultimate goal of developing RV-targeted therapies for patients with RV failure of any etiology.

Fatal Microscopic Pulmonary Tumor Thromboemboli: Unusual Presentation of Occult Cervical Carcinoma. Two Case Reports and Review of the Literature

Cor pulmonale (right heart failure) due to microscopic pulmonary tumor emboli (MPTE) can arise from a variety of malignancies including breast, lung, and liver and carries significant morbidity and mortality. Tumor cell aggregates spread hematogenously to the lungs and occlude small pulmonary vessels leading to pulmonary hypertension through either a mechanical process or inducing vascular remodeling as a downstream result of interactions between the embolus and the vessel wall. Its presentation includes unexplained dyspnea, hypoxemia, tachycardia, pulmonary hypertension, right heart failure, and in some cases sudden death. The symptoms may suggest the more common entity of pulmonary thromboembolism, particularly in the setting of previously known metastatic cancer; however, computed tomography scans may appear normal and ventilation-perfusion scans which are the preferable diagnostic modality are not always ordered. In most cases of MPTE, the presentation reflects metastasis of an already known and advanced tumor, but, in rare cases, it may be the primary manifestation of an occult malignancy. We present here 2 unique cases of MPTE in women with occult cervical cancer. In both cases, the malignancy was discovered and diagnosed at autopsy. Microscopic pulmonary tumor emboli can be easily overlooked, and therefore, forensic pathologists and other death investigators should be aware of it and trained to at least consider the possibility in appropriate situations. Thorough microscopic examination of apparently normal tissues may be necessary, particularly in cases of unexplained right heart failure and sudden death, even if the decedent has few or no identifiable risk factors for cancer.

EXPRESS: Right Heart in Pulmonary Hypertension: From Adaptation to Failure

Right ventricular (RV) failure (RVF) has garnered significant attention in recent years because of its negative impact on clinical outcomes in patients with pulmonary hypertension (PH). PH triggers a series of events, including activation of several signaling pathways that regulate cell growth, metabolism, extracellular matrix remodeling, and energy production. These processes render the RV adaptive to PH. However, RVF develops when PH persists, accompanied by RV ischemia, alterations in substrate and mitochondrial energy metabolism, increased free oxygen radicals, increased cell loss, downregulation of adrenergic receptors, increased inflammation and fibrosis, and pathologic microRNAs. Diastolic dysfunction is also an integral part of RVF. Emerging non-invasive technologies such as molecular or metallic imaging, cardiac MRI, and ultrafast Doppler coronary flow mapping will be valuable tools to monitor RVF, especially the transition to RVF. Most PH therapies cannot treat RVF once it has occurred. A variety of therapies are available to treat acute and chronic RVF, but they are mainly supportive, and no effective therapy directly targets the failing RV. Therapies that target cell growth, cellular metabolism, oxidative stress, and myocyte regeneration are being tested preclinically. Future research should include establishing novel RVF models based on existing models, increasing use of human samples, creating human stem cell-based in vitro models, and characterizing alterations in cardiac excitation–contraction coupling during transition from adaptive RV to RVF. More successful strategies to manage RVF will likely be developed as we learn more about the transition from adaptive remodeling to maladaptive RVF in the future.

Aggressive Treatment of Intermediate-Risk Patients with Acute Symptomatic Pulmonary Embolism

Contemporary studies of acute pulmonary embolism (PE) have evaluated the role of thrombolytics in intermediate-risk PE. Significant findings are that thrombolytic therapy may prevent hemodynamic deterioration and all-cause mortality but increases major bleeding. Benefits and harms are finely balanced with no convincing net benefit from thrombolytic therapy among unselected patients. Among patients with intermediate risk PE, additional prognostic factors or subtle hemodynamic changes might alter the risk-benefit assessment in favor of thrombolytic therapy before obvious hemodynamic instability.

Right heart dysfunction: from pathophysiologic insights to therapeutic options: a translational overview

: The right ventricle has become increasingly studied in cardiovascular research. In this article, we describe specific pathophysiological characteristics of the right ventricle, with special focus on functional and molecular modifications as well as therapeutic strategies in right ventricular dysfunction, underlining the differences with the left ventricle. Then we analyze the main imaging modalities to assess right ventricular function in different clinical settings. Finally, we acknowledge main therapeutic advances for treatment of right heart diseases.

[Pathophysiology of right ventricular hemodynamics]

The right ventricle (RV) plays a key role in the maintenance of an adequate cardiac output whatever the demand, and thus contributes to the optimization of the ventilation/perfusion ratio. The RV has a thin wall and it buffers the physiological increases in systemic venous return without causing a deleterious rise in right atrial pressure (RAP). The RV is coupled to the pulmonary circulation which is a low pressure, low resistance, high compliance system. In the healthy subject at rest, the contribution of the RV to right heart systolic function is surpassed by the contribution of both left ventricular contraction and the respiratory pump. RV systolic function plays a contributory role during exercise and in patients with pulmonary hypertension. The RV compensates better for volume overload than for pressure overload and is more capable of sustaining chronic increases in load than acute ones. An impaired RV-pulmonary artery coupling leads to a major mismatch between RV function and arterial load ("afterload mismatch") and is associated progressively with a low cardiac output and a high RAP. Right ventricular dysfunction is involved in the pathophysiology of both cardiovascular and pulmonary diseases, and may partly explain the deleterious haemodynamic consequences of mechanical ventilation.

Evaluation and Management of Right-Sided Heart Failure: A Scientific Statement From the American Heart Association

Background and Purpose:

The diverse causes of right-sided heart failure (RHF) include, among others, primary cardiomyopathies with right ventricular (RV) involvement, RV ischemia and infarction, volume loading caused by cardiac lesions associated with congenital heart disease and valvular pathologies, and pressure loading resulting from pulmonic stenosis or pulmonary hypertension from a variety of causes, including left-sided heart disease. Progressive RV dysfunction in these disease states is associated with increased morbidity and mortality. The purpose of this scientific statement is to provide guidance on the assessment and management of RHF.

Methods:

The writing group used systematic literature reviews, published translational and clinical studies, clinical practice guidelines, and expert opinion/statements to summarize existing evidence and to identify areas of inadequacy requiring future research. The panel reviewed the most relevant adult medical literature excluding routine laboratory tests using MEDLINE, EMBASE, and Web of Science through September 2017. The document is organized and classified according to the American Heart Association to provide specific suggestions, considerations, or reference to contemporary clinical practice recommendations.

Results:

Chronic RHF is associated with decreased exercise tolerance, poor functional capacity, decreased cardiac output and progressive end-organ damage (caused by a combination of end-organ venous congestion and underperfusion), and cachexia resulting from poor absorption of nutrients, as well as a systemic proinflammatory state. It is the principal cause of death in patients with pulmonary arterial hypertension. Similarly, acute RHF is associated with hemodynamic instability and is the primary cause of death in patients presenting with massive pulmonary embolism, RV myocardial infarction, and postcardiotomy shock associated with cardiac surgery. Functional assessment of the right side of the heart can be hindered by its complex geometry. Multiple hemodynamic and biochemical markers are associated with worsening RHF and can serve to guide clinical assessment and therapeutic decision making. Pharmacological and mechanical interventions targeting isolated acute and chronic RHF have not been well investigated. Specific therapies promoting stabilization and recovery of RV function are lacking.

Conclusions:

RHF is a complex syndrome including diverse causes, pathways, and pathological processes. In this scientific statement, we review the causes and epidemiology of RV dysfunction and the pathophysiology of acute and chronic RHF and provide guidance for the management of the associated conditions leading to and caused by RHF.

The relation between international normalized ratio and mortality in acute pulmonary embolism: A retrospective study

BACKGROUND

Acute pulmonary embolism (PE) is a serious clinical disease characterized by a high mortality rate. The aim of this study was to assess the prognostic value of international normalized ratio (INR) in acute PE patients not on anticoagulant therapy.

METHODS

The study included 244 hospitalized acute PE patients who were not receiving previous anticoagulant therapy. Based on their 30-day mortality, patients were categorized as survivors or non-survivors. INR was measured during the patients' admission, on the same day as the diagnosis of PE but before anticoagulation started.

RESULTS

Thirty-day mortality occurred in 39 patients (16%). INR was higher in non-survivors than in survivors (1.3±0.4 vs 1.1±0.3, P=.003). In multivariate analysis, INR (HR: 3.303, 95% CI: 1.210-9.016, P=.020) was independently associated with 30-day mortality from PE. Inclusion of INR in a model with simplified pulmonary embolism severity index (sPESI) score improved the area under the receiver operating characteristics (ROC) curve from 0.736 (95% CI: 0.659-0.814) to 0.775 (95% CI: 0.701-0.849) (P=.028). Also, the addition of INR to sPESI score enhanced the net reclassification improvement (NRI=8.8%, P<.001) and integrated discrimination improvement (IDI=0.043, P=.027).

CONCLUSION

Elevated INR may have prognostic value for 30-day mortality in acute PE patients not on anticoagulation. Combining INR with sPESI score improved the predictive value for all-cause mortality. However, further large-scale studies are needed to confirm it's prognostic role.

Acute Right Ventricular Dysfunction in Intensive Care Unit

The role of the left ventricle in ICU patients with circulatory shock has long been considered. However, acute right ventricle (RV) dysfunction causes and aggravates many common critical diseases (acute respiratory distress syndrome, pulmonary embolism, acute myocardial infarction, and postoperative cardiac surgery). Several supportive therapies, including mechanical ventilation and fluid management, can make RV dysfunction worse, potentially exacerbating shock. We briefly review the epidemiology, pathophysiology, diagnosis, and recommendations to guide management of acute RV dysfunction in ICU patients. Our aim is to clarify the complex effects of mechanical ventilation, fluid therapy, vasoactive drug infusions, and other therapies to resuscitate the critical patient optimally.

Platelet hyperactivation, apoptosis and hypercoagulability in patients with acute pulmonary embolism

Changes in systemic redox balance can alter platelet activation and aggregation. Acute pulmonary embolism (PE) is a systematic inflammatory disease associated with mechanical shear stress, increased thrombin, catecholamines, serotonin and hemolysis, which cumulatively can hyperactivate platelets and accelerate their turnover. We tested the hypothesis that platelets from patients with moderately severe PE will show hyperstimulation and a pre-apoptotic phenotype associated with microparticles (MPs) in plasma. Blood for platelet respiration and thromboelastography (TEG) was obtained at diagnosis and 24h later from patients (n=76) with image-proven PE, SBP>90mmHg and right ventricular dysfunction demonstrated by echocardiogram or elevated biomarkers. Controls (n=12) were healthy volunteers. At diagnosis, platelets from PE patients had significantly elevated baseline oxygen consumption compared with controls, explained primarily by accelerated electron transport and oxygen wasting with no measurable extramitochondrial oxygen consumption. On thromboelastography, unstimulated thrombin-independent maximum amplitude was increased with PE, 19±14.1 vs.10.5±7.8mm in controls (p=0.002). Compared with controls, platelets from PE patients showed elevated mitochondrial reactive oxygen species with decreased mitochondrial Bcl-2 protein content and increased cytosolic cytochrome C, coincident with strong annexin V binding, P selectin release from lysed platelets and in plasma MPs compared to controls (p<0.05). These results show evidence of platelet hyperactivation and apoptosis in patients with acute PE, and provide preliminary theoretical basis for further exploration of platelet inhibition in patients with more severe PE.

Recent Progress in Research on the Pathogenesis of Pulmonary Thromboembolism: An Old Story with New Perspectives

Pulmonary thromboembolism (PTE) is part of a larger clinicopathological entity, venous thromboembolism. It is also a complex, multifactorial disorder divided into four major disease processes including venous thrombosis, thrombus in transit, acute pulmonary embolism, and pulmonary circulation reconstruction. Even when treated, some patients develop chronic thromboembolic pulmonary hypertension. PTE is also a common fatal type of pulmonary vascular disease worldwide, but earlier studies primarily focused on the pathological changes in the blood component of the disease. With contemporary advances in molecular and cellular biology, people are becoming increasingly aware of coagulation pathways, the function of vascular smooth muscle cells, microparticles, and the inflammatory pathways that play key roles in PTE. Combined hypoxia and immune research has revealed that PTE should be regarded as a class of complex diseases caused by multiple factors involving the vascular microenvironment and vascular cell dysfunction.

Right ventricular function during acute exacerbation of severe equine asthma

BACKGROUND

Pulmonary hypertension has been described in horses with severe equine asthma, but its effect on the right ventricle has not been fully elucidated.

OBJECTIVES

To evaluate right ventricular structure and function after a 1-week period of pulmonary hypertension secondary to acute exacerbation of severe equine asthma.

STUDY DESIGN

Prospective study.

METHODS

A clinical episode of severe equine asthma was induced experimentally in six susceptible horses. Examinations in remission and on day 7 of the clinical episode included a physical examination with clinical scoring, echocardiography, arterial blood gas measurements, venous blood sampling for cardiac biomarkers, intracardiac pressure measurements, right ventricular and right atrial myocardial biopsies, airway endoscopy and bronchoalveolar lavage. After 1 month of recovery, physical examination, echocardiography and cardiac biomarker analysis were repeated. Echocardiographic and pressure measurements were compared with those in 10 healthy control horses.

RESULTS

All horses developed clinical signs of acute pulmonary obstruction. Right heart pressures increased significantly. Altered right ventricular function could be detected by tissue Doppler and speckle tracking echocardiography. Cardiac troponin concentrations did not increase significantly, but were highly elevated in one horse which exercised in the paddock prior to sampling. Focal neutrophil infiltration was present in two myocardial samples. Even in remission, asthmatic horses showed a thicker right ventricular wall, an increased left ventricular end-systolic eccentricity index at chordal level and decreased right ventricular longitudinal strain compared with controls.

MAIN LIMITATIONS

The induced clinical episode was rather mild and the number of horses was limited because of the invasive nature of the study.

CONCLUSIONS

Pulmonary obstruction in asthmatic horses induces pulmonary hypertension with right ventricular structural and functional changes.

Differential effect of mild and severe pulmonary embolism on the rat lung transcriptome

BACKGROUND

Pulmonary thromboembolism (PTE) is a common diagnosis and a leading cause of cardiovascular morbidity and mortality. A growing literature has associated PE with systemic inflammation, and global hyper-coagulability, which contribute to lung remodeling and clot recurrence. The source and mechanism of inflammation remains unstudied. In humans, inhibition of cholesterol synthesis with statins decreases biomarkers of inflammation. We test the differential effect of pulmonary vascular occlusion during mild and severe pulmonary embolism on the lung transcriptome.

METHODS

Experimental PE was induced in adult male rats by injection of 25 micron polystyrene microspheres into the jugular vein. The effect of Mild PE, (2-h right ventricular systolic pressure [RVSP] normal, 18-h RVSP 44 mmHg) and Severe PE (2-h RVSP > 50 mmHg; 18-h RVSP 44 mmHg) on lungs was assessed by measuring transcriptome-wide changes in gene expression by DNA microarrays.

RESULTS

Severe PE was associated with a large change in lung gene expression and in the expression of KEGG pathways and other gene functional annotation groups. Mild PE was also associated with a large number of significant changes in gene expression and in the expression of KEGG pathways and gene functional annotation groups, even after only 2 h of PE. Up-regulated pathways included increased adipocytokine, chemokine and cytokine signaling as well as cholesterol synthesis.

CONCLUSIONS

Mild PE without acute pulmonary hypertension (PH) increased lung gene expression of inflammatory pathways, including increased cholesterol synthesis. These data indicate that even mild persistent pulmonary vascular occlusion is capable of inciting an inflammatory response from the lung. These data imply the detrimental effect of unresolved pulmonary obstruction from PE.

Development and Characterization of an Inducible Rat Model of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is an entity of PH that not only limits patients quality of life but also causes significant morbidity and mortality. The treatment of choice is pulmonary endarterectomy. However numerous patients do not qualify for pulmonary endarterectomy or present with residual vasculopathy post pulmonary endarterectomy and require specific vasodilator treatment. Currently, there is no available specific small animal model of CTEPH that could serve as tool to identify targetable molecular pathways and to test new treatment options. Thus, we generated and standardized a rat model that not only resembles functional and histological features of CTEPH but also emulates thrombi fibrosis. The pulmonary embolism protocol consisted of 3 sequential tail vein injections of fibrinogen/collagen-covered polystyrene microspheres combined with thrombin and administered to 10-week-old male Wistar rats. After the third embolism, rats developed characteristic features of CTEPH including elevated right ventricular systolic pressure, right ventricular cardiomyocyte hypertrophy, pulmonary artery remodeling, increased serum brain natriuretic peptide levels, thrombi fibrosis, and formation of pulmonary cellular-fibrotic lesions. The current animal model seems suitable for detailed study of CTEPH pathophysiology and permits preclinical testing of new pharmacological therapies against CTEPH.

Pulmonary Hypertension and Right Ventricular Failure in Emergency Medicine

Pulmonary hypertension is a hemodynamic condition, defined as a mean pulmonary artery pressure by right-sided heart catheterization of at least 25 mm Hg at rest. It is classified into 5 general groups based on the underlying cause, with left ventricular failure and chronic obstructive pulmonary disease being 2 of the most common causes in the United States. Although the specifics of the pathophysiology will vary with the cause, appreciating the risks of pulmonary hypertension and right ventricular failure is critical to appropriately evaluating and resuscitating pulmonary hypertension patients in the emergency department (ED). Patients may present to the ED with complaints related to pulmonary hypertension or unrelated ones, but this condition will affect all aspects of care. Exertional dyspnea is the most common symptom attributable to pulmonary hypertension, but the latter should be considered in any ED patient with unexplained dyspnea on exertion, syncope, or signs of right ventricular dysfunction. Patients with right ventricular failure are often volume overloaded, and careful volume management is imperative, especially in the setting of hypotension. Vasopressors and inotropes, rather than fluid boluses, are often required in shock to augment cardiac output and reduce the risk of exacerbating right ventricular ischemia. Intubation should be avoided if possible, although hypoxemia and hypercapnia may also worsen right-sided heart function. Emergency physicians should appreciate the role of pulmonary vasodilators in the treatment of pulmonary arterial hypertension and recognize that patients receiving these medications may rapidly develop right ventricular failure and even death without these therapies. Patients may require interventions not readily available in the ED, such as a pulmonary artery catheter, inhaled pulmonary vasodilators, and mechanical support with a right ventricular assist device or extracorporeal membrane oxygenation. Therefore, early consultation with a pulmonary hypertension specialist and transfer to a tertiary care center with invasive monitoring and mechanical support capabilities is advised.

Advancing knowledge of right ventricular pathophysiology in chronic pressure overload: Insights from experimental studies

The right ventricle (RV) has to face major changes in loading conditions due to cardiovascular diseases and pulmonary vascular disorders. Clinical experience supports evidence that the RV better compensates for volume than for pressure overload, and for chronic than for acute changes. For a long time, right ventricular (RV) pathophysiology has been restricted to patterns extrapolated from left heart studies. However, the two ventricles are anatomically, haemodynamically and functionally distinct. RV metabolic properties may also result in a different behaviour in response to pathological conditions compared with the left ventricle. In this review, current knowledge of RV pathophysiology is reported in the setting of chronic pressure overload, including recent experimental findings and emerging concepts. After a time-varying compensated period with preserved cardiac output despite overload conditions, RV failure finally occurs, leading to death. The underlying mechanisms involved in the transition from compensatory hypertrophy to maladaptive remodelling are not completely understood.

Pulmonary Hypertension in the Intensive Care Unit

Pulmonary hypertension occurs as the result of disease processes increasing pressure within the pulmonary circulation, eventually leading to right ventricular failure. Patients may become critically ill from complications of pulmonary hypertension and right ventricular failure or may develop pulmonary hypertension as the result of critical illness. Diagnostic testing should evaluate for common causes such as left heart failure, hypoxemic lung disease and pulmonary embolism. Relatively few patients with pulmonary hypertension encountered in clinical practice require specific pharmacologic treatment of pulmonary hypertension targeting the pulmonary vasculature. Management of right ventricular failure involves optimization of preload, maintenance of systemic blood pressure and augmentation of inotropy to restore systemic perfusion. Selected patients may require pharmacologic therapy to reduce right ventricular afterload by directly targeting the pulmonary vasculature, but only after excluding elevated left heart filling pressures and confirming increased pulmonary vascular resistance. Critically-ill patients with pulmonary hypertension remain at high risk of adverse outcomes, requiring a diligent and thoughtful approach to diagnosis and treatment.

Adaptive capacity of the right ventricle: why does it fail?

Only in recent years has the right ventricle (RV) function become appreciated to be equally important to the left ventricle (LV) function to maintain cardiac output. Right ventricular failure is, irrespectively of the etiology, associated with impaired exercise tolerance and poor survival. Since the anatomy and physiology of the RV is distinctly different than that of the LV, its adaptive mechanisms and the pathways involved are different as well. RV hypertrophy is an important mechanism of the RV to preserve cardiac output. This review summarizes the current knowledge on the right ventricle and its response to pathologic situations. We will focus on the adaptive capacity of the right ventricle and the molecular pathways involved, and we will discuss potential therapeutic interventions.

Association between electrocardiographic findings, right heart strain, and short-term adverse clinical events in patients with acute pulmonary embolism

BACKGROUND

Electrocardiographic (ECG) changes may be seen with pulmonary emboli (PE). Whether ECG is associated with short-term adverse clinical events after PE is less well established.

HYPOTHESIS

ECG findings are associated with short-term clinical deterioration after PE.

METHODS

Consecutive adult PE patients were enrolled in an academic emergency department from 2008 to 2011. The primary outcome was right heart strain (RHS) on echocardiogram or CT pulmonary angiography, or TnT ≥0.1 ng/mL. We derived an ECG (TwiST) score that is associated with RHS and short-term adverse clinical events.

RESULTS

We enrolled 298 patients with PE. On multivariate analysis, T-wave inversion in leads V(1) through V(3) (OR: 4.7, 95% confidence interval [CI]: 1.7-13.2), S wave in lead I (OR: 2.0, 95% CI: 1.1-3.5), and tachycardia (OR: 2.5, 95% CI: 1.3-4.8) were associated with RHS. A TwiST score ≤2 (n = 210, 72%) was 84% (95% CI: 77%-90%) sensitive for the absence of RHS, whereas a TwiST score ≥5 (n = 47, 16%) was 93% (95% CI: 88%-97%) specific for the presence of RHS.

CONCLUSIONS

A simple ECG (TwiST) score can identify patients likely or not likely to have RHS with >80% specificity and sensitivity and may assist in identifying patients with acute PE at risk for adverse clinical events before pursuing other advanced imaging tests.

Right heart adaptation to pulmonary arterial hypertension: physiology and pathobiology

Survival in patients with pulmonary arterial hypertension (PAH) is closely related to right ventricular (RV) function. Although pulmonary load is an important determinant of RV systolic function in PAH, there remains a significant variability in RV adaptation to pulmonary hypertension. In this report, the authors discuss the emerging concepts of right heart pathobiology in PAH. More specifically, the discussion focuses on the following questions. 1) How is right heart failure syndrome best defined? 2) What are the underlying molecular mechanisms of the failing right ventricle in PAH? 3) How are RV contractility and function and their prognostic implications best assessed? 4) What is the role of targeted RV therapy? Throughout the report, the authors highlight differences between right and left heart failure and outline key areas of future investigation.

ESC Working Group on Myocardial Function Position Paper: how to study the right ventricle in experimental models

The right ventricle has become an increasing focus in cardiovascular research. In this position paper, we give a brief overview of the specific pathophysiological features of the right ventricle, with particular emphasis on functional and molecular modifications as well as therapeutic strategies in chronic overload, highlighting the differences from the left ventricle. Importantly, we put together recommendations on promising topics of research in the field, experimental study design, and functional evaluation of the right ventricle in experimental models, from non-invasive methodologies to haemodynamic evaluation and ex vivo set-ups.

Right ventricular function in acute pulmonary embolism: a combined assessment by three-dimensional and speckle-tracking echocardiography

BACKGROUND

The aim of this study was to assess changes in right ventricular (RV) parameters determined by three-dimensional (3D) echocardiography and speckle-tracking echocardiography in patients with acute pulmonary embolism and RV dysfunction without systemic hypotension (submassive pulmonary embolism).

METHODS

Sixty-six patients were prospectively studied at the onset of the acute episode and after median follow-up periods of 30 days and 6 months. Sixty-six controls were selected. RV fractional area change, tricuspid annular plane systolic excursion, and myocardial performance index were determined. RV systolic pressure was assessed using continuous-wave Doppler echocardiography. Three-dimensional RV ejection fraction (RVEF) was calculated. Two-dimensional peak systolic RV longitudinal strain (RVLS) was measured in the basal free wall, mid free wall (MFW), and apical free wall and the septum.

RESULTS

Tricuspid annular plane systolic excursion and fractional area change were smaller and myocardial performance index was larger compared with controls (P < .05). Global RVLS (P < .05), MFW RVLS (P < .001), and 3D RVEF (P < .001) were lower in patients with pulmonary embolism than in controls. There was earlier reversal of MFW RVLS values on 30-day follow-up and longer reversal of 3D RVEF and RV systolic pressure values at 6-month follow-up. Receiver operating characteristic curve analysis showed that changes in 3D RVEF and MFW RVLS were the most sensitive predictors of adverse events. By multivariate analysis, RV systolic pressure (P = .007), MFW RVLS (P = .002), and 3D RVEF (P = .001) were independently associated with adverse outcomes.

CONCLUSIONS

Acute submassive pulmonary embolism has a significant impact on RV function as assessed by 3D echocardiography and speckle-tracking echocardiography. Decreases in MFW RVLS and 3D RVEF may persist during short-term and long-term follow-up and correlate with unfavorable outcomes.

White blood cell count and mortality in patients with acute pulmonary embolism

Although associated with adverse outcomes in other cardiovascular diseases, the prognostic value of an elevated white blood cell (WBC) count, a marker of inflammation and hypercoagulability, is uncertain in patients with pulmonary embolism (PE). We therefore sought to assess the prognostic impact of the WBC in a large, state-wide retrospective cohort of patients with PE. We evaluated 14,228 patient discharges with a primary diagnosis of PE from 186 hospitals in Pennsylvania. We used random-intercept logistic regression to assess the independent association between WBC count levels at the time of presentation and mortality and hospital readmission within 30 days, adjusting for patient and hospital characteristics. Patients with an admission WBC count <5.0, 5.0-7.8, 7.9-9.8, 9.9-12.6, and >12.6 × 10(9) /L had a cumulative 30-day mortality of 10.9%, 6.2%, 5.4%, 8.3%, and 16.3% (P < 0.001), and a readmission rate of 17.6%, 11.9%, 10.9%, 11.5%, and 15.0%, respectively (P < 0.001). Compared with patients with a WBC count 7.9-9.8 × 10(9) /L, adjusted odds of 30-day mortality were significantly greater for patients with a WBC count <5.0 × 10(9) /L (odds ratio [OR] 1.52, 95% confidence interval [CI] 1.14-2.03), 9.9-12.6 × 10(9) /L (OR 1.55, 95% CI 1.26-1.91), or >12.6 × 10(9) /L (OR 2.22, 95% CI 1.83-2.69), respectively. The adjusted odds of readmission were also significantly increased for patients with a WBC count <5.0 × 10(9) /L (OR 1.34, 95% CI 1.07-1.68) or >12.6 × 10(9) /L (OR 1.29, 95% CI 1.10-1.51). In patients presenting with PE, WBC count is an independent predictor of short-term mortality and hospital readmission.

Acute improvement in right ventricular function after treatment of presumed massive pulmonary embolism with thrombolytics

Acute massive pulmonary embolism results in a rise in pulmonary vascular resistance and acute right ventricular dilation and systolic dysfunction. In unstable patients who cannot safely undergo computed tomography, echocardiography can often provide direct and indirect evidence of pulmonary embolism. We present a case in which clinical and echocardiographic evidence provided sufficient evidence of PE to initiate treatment. Dynamic improvement in hemodynamics and echocardiographic parameters of RV function indicated successful treatment.