Major pulmonary embolism: review of a pathophysiologic approach to the golden hour of hemodynamically significant pulmonary embolism

The Design of PE Dx, a CDS to Support Pulmonary Embolism Diagnosis in the ED

Designing and implementing clinical decision support (CDS) in health care has been challenging. Attempts have been made to design and implement CDS to support clinical procedures, but many of these CDSs have met user resistance. One possible explanation for the lack of acceptability can be the poor design of the CDS. In this study, we describe the design of PE Dx, a CDS built to support the diagnosis of pulmonary embolism (PE) in the emergency department (ED) using human factors methods.

Endogenously released adenosine causes pulmonary vasodilation during the acute phase of pulmonary embolization in dogs

Background

Endogenous adenosine levels increase under stress in various organs. Exogenously administered adenosine is a well-known pulmonary vasodilator. However, the physiology and therapeutic potential of endogenous adenosine during alteration in pulmonary hemodynamics such as pulmonary embolism is not elucidated. We hypothesized that the adenosine level increases following an acute elevation of pulmonary resistance, resulting in pulmonary vasodilation.

Methods

We induced acute pulmonary embolization by injecting plastic beads in anesthetized dogs. Plasma adenosine levels, defined as the product of plasma adenosine concentration and simultaneous cardiac output, were assessed from blood samples from the superior vena cava, main pulmonary artery (MPA), and ascending aorta 1 and 10 min following injection. Hemodynamics were assessed with (n = 3) and without (n = 8) administration of the adenosine receptor blocker, 8-(p-sulfophenyl)theophylline (8SPT).

Results

Mean pulmonary arterial pressure (PAP) increased from 11 ± 1 mmHg, peaking at 28 ± 4 mmHg at 52 ± 13 s after injection. During this period, total pulmonary resistance (TPR) elevated from 11 ± 1 to 33 ± 6 Wood unit. Plasma adenosine levels increased in the MPA from 14.5 ± 2 to 38.8 ± 7 nmol/min 1 min after injection. TPR showed greater elevation under 8SPT treatment, to 96 ± 12 Wood unit at PAP peak.

Conclusions

Endogenously released adenosine after acute pulmonary embolization is one of the initial pulmonary vasodilators. The immediate surge in plasma adenosine levels in the MPA could lead to a hypothesis that adenosine is released by the right heart in response to pressure overload.

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Adenosine levels increased after experimental acute pulmonary embolization.

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Plasma adenosine levels immediately rose in the main pulmonary artery.

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Adenosine is one of the initial pulmonary vasodilators after embolization.

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Released adenosine could originate from the right heart following pressure overload.

The Association between the Pulmonary Arterial Obstruction Index and Atrial Size in Patients with Acute Pulmonary Embolism

Purpose

Pulmonary embolism (PE) is a common and potentially fatal form of venous thromboembolism. The aim of this study is to investigate the association between the pulmonary arterial obstruction index and atrial size in patients with acute pulmonary embolism.

Basic Procedure

The study consisted of 86 patients with clinical symptoms of PE. Out of 86 individuals, 50 patients were diagnosed with PE and considered as the patient group. The others were considered as the control group. All patients were scanned by a multidetector CT scanner. Using the radiology workstation, an expert radiologist calculated the left atrium (LA) and right atrium (RA) areas from planimetric measurements obtained from free-hand delineation of the atrial boarders using an electronic pen. Quantitative volumetric measurements of LA and RA were obtained from original axial images.

Main Findings

There were 25 males and 25 females with PE, who had a mean age of 58 years. There was not a significant difference in the positive history of diabetes mellitus, hypertension, asthma, chronic obstructive pulmonary diseases, ischemic heart disease, and smoking between patients and control group. There was a significant negative correlation between almost all LA measurements and the PAOI. RA area and volume had the highest area under the curves for recognizing larger clot burden.

Principal Conclusions

A higher clot load is associated with a smaller LA size and increased RA/LA ratios, measured with CTPA. Atrial measurements are correlated with POAI, and they could be used as sensitive parameters in predicting heart failure in patients with PE.

Management of Low-Risk Pulmonary Embolism

Pulmonary embolism remains a leading cause of morbidity and mortality in the United States. However, with improved recognition and diagnosis, the risk of death diminishes. The diagnosis depends on the clinician's suspicion. Pulmonary emboli are categorized into low, intermediate, or high risk based on the scoring scales and patients' hemodynamic stability versus instability. Imaging plus biomarkers help stratify patients according to risk. With the advent of the computed tomography multidetector scanners, the improved imaging has increased the detection of subsegmental and incidental pulmonary emboli. Treatment of low-risk as well as subsegmental and incidental pulmonary embolism is evolving.

Non-operating room anaesthesia for embolisation of ductus closure device to the pulmonary artery in a child with patent ductus arteriosus

ABSTRACTPatent ductus arteriosus is among the most common congenital heart diseases. With the increasing use of transcatheter closure procedures, the incidence of complications related to the procedure has increased. Embolization of the ductus closure device to the pulmonary artery is a very rare complication. Since those procedures are often performed under non-operating room anesthesia, anesthetic management of such patients is of great importance. Herein, anesthetic management of embolization of the ductus closure device to the pulmonary artery in a little girl was presented. This is the first case regarding the anesthetic management of such complication.

Systematic review of civilian intravascular ballistic embolism reports during the last 30 years

BACKGROUND

Intravascular ballistic embolization is a rare complication of missile injury. Because of its rarity, much remains to be known about its presentation, pathophysiology, complications, and management. In this study, we analyze case reports of ballistic embolization in the last 30 years and available cases from our institution to determine the likely patient, the nature of the embolization, the possible complications, and a general management strategy.

METHODS

A PubMed search was performed in search of missile embolization cases from 1988 to 2018 in the English language, including only cases of intravascular emboli. Cases resulting from combat and explosive devices were excluded. In addition, five cases from our institution were included in the analysis.

RESULTS

A total of 261 cases were analyzed. The most common presentation was that of a young man (reflecting the demographics of those sustaining gunshot wound injuries) with injury to the anterior torso from a single gunshot wound. Venous entry was most common, most often through large-caliber vessels. There was roughly equal involvement of the right and left circulation. Left circulation emboli were frequently symptomatic, with ischemia being the most frequent sequela. In contrast, a right circulation embolus was rarely associated with significant complications.

CONCLUSIONS

Despite its rarity, ballistic embolization should be considered in gunshot injury with known large-vessel injury when an exit wound is not identified. In particular, signs of ischemia distant from the injury site warrant timely investigation to maximize tissue salvageability. We present a management strategy model for consideration.

Assessing the Impact of a Pulmonary Embolism Response Team and Treatment Protocol on Patients Presenting With Acute Pulmonary Embolism

BACKGROUND

Pulmonary embolism (PE) care has traditionally been fragmented. The newly introduced Pulmonary Embolism Response Team (PERT) model provides streamlined care based on expedient, multi-disciplinary decision-making. This study aimed to quantify the impact of PERT, as part of a hospital-wide PE treatment protocol, on clinical outcomes.

METHODS

Consecutive adult patients with acute PE diagnosed via computed tomography pulmonary angiogram (CTPA) were included. The PERT and treatment protocol were introduced in January 2015. Patient characteristics, therapies, quality measures of CTPA reporting, and clinical outcomes of PE patients treated for 2 years before and after implementation of these changes were evaluated. Primary endpoints were median length of stay in intensive care (ICU) and survival to discharge.

RESULTS

A total of 321 consecutive PE patients were enrolled, of which 154 (treated in 2013-2014) and 167 (2015-2016) patients formed the historical control and study groups, respectively. Implementation of the algorithm was associated with less variance in anticoagulation and improved reporting of right heart strain parameters on CTPA. The ICU stay was reduced from a median of 5 to 2 days (p < 0.01). Eligible massive PE patients receiving reperfusion increased from 30% to 92% (p = 0.01), with mean delay from diagnosis to reperfusion decreasing from 763 to 181 minutes (p < 0.01). Bleeding complications were not increased, but overall survival to discharge remained unchanged.

CONCLUSIONS

Introducing a PERT and treatment protocol reduced ICU stay, enhanced quality measures, and improved access of massive PE patients to reperfusion therapies, without increasing bleeding complications or health care costs.

Pathophysiology of right ventricular failure in acute pulmonary embolism and chronic thromboembolic pulmonary hypertension: a pictorial essay for the interventional radiologist

Pulmonary embolus (PE) is the third most common cause of cardiovascular death with more than 600,000 cases occurring in the USA per year. About 45% of patients with acute PE will have acute right ventricular failure, and up to 3.8% of patients will develop chronic thromboembolic pulmonary hypertension (CTEPH) with progressive, severe, chronic heart failure. The right ventricle (RV) is constructed to accommodate a low-resistance afterload. Increases in afterload from acute massive and submassive PE and CTEPH may markedly compromise the RV function leading to hemodynamic collapse and death. The purpose of this educational manuscript is to instruct on the pathophysiology of RV failure in massive and submassive PE and CTEPH. It is important to understand the pathophysiology of these diseases as it provides the rationale for therapeutic intervention by the Interventional Radiologist. We review here the pathophysiology of right ventricular (RV) failure in acute massive and submassive PE and CTEPH.

Prognostic implications of small left atria on hospitalized patients

Aims

To demonstrate the association between small left atria (LA) and outcome in a relatively large heterogeneous population of hospitalized patients.

Methods and results

In a single-centre retrospective study, all inpatients that underwent an echocardiographic assessment between 2011 and 2016 and had an available left atrial volume index (LAVI) measurement were included. The cohort consisted of 17 343 inpatients who had an available LAVI measurement, 288 with small LA (LAVI <16 mL/m2), 7531 patients had LAVI within normal limits (16–34 mL/m2) divided into low normal (16–24.9 mL/m2; n = 2636) and high normal (25–34 mL/m2; n = 4895), 4720 patients had large LAVI (34.1–45 mL/m2) and 4804 had very large LAVI (>45 mL/m2). Median follow-up time was 2.4 years. After adjustments for age, gender, and baseline characteristics with a P-value <0.2 in univariable analyses (body mass index, haemoglobin, ischaemic heart disease, valvulopathy, atrial fibrillation, diabetes mellitus, hypertension, hyperlipidaemia, smoking, renal dysfunction, lung disease, and malignancy) small LA was associated with a higher risk for in-hospital mortality (odds ratio 2.9, 95% confidence interval (CI) 1.4–5.7; P = 0.002] and all-cause mortality [hazard ratio (HR) 2.1, 95% CI 1.6–2.8; P < 0.001] compared with high normal LA. For every mL/m2 decrease below high normal LA size the risk for in-hospital and long-term all-cause mortality increased by 10% (HR 1.1, 95% CI 1.02–1.18; P = 0.005) and 8% (HR 1.08, 95% CI 1.05–1.12; P < 0.001), respectively.

Conclusion

Small LA are independently associated poorer short- and long-term mortality. LA volume should be referred to as J-shaped in terms of mortality.

Helsinki committee approval number

0170-17-TLV.

Pulmonary Arteriovenous Malformation Masquerading as Massive Pulmonary Thromboembolus

We present a case of a 78-year-old male with hereditary haemorrhagic telangiectasia and severe hypoxia incorrectly diagnosed as pulmonary embolism following a false positive ventilation/perfusion scan. Anti-coagulation and thrombolysis was complicated by an upper gastro-intestinal haemorrhage. Pulmonary arteriovenous malformations resulted in a clinically significant right-left shunt and created an apparent perfusion defect evident upon radionuclide imaging, leading to diagnostic uncertainty and a potentially dangerous treatment modality.

Treatment of the acute severe pulmonary embolism using endovascular methods

Purpose

To present a single-centre experience with endovascular treatment of patients with severe symptoms secondary to acute pulmonary embolism (PE).

Material and methods

Twenty-five patients were treated due to contraindications or deficient effects of systemic thrombolytic therapy. The patients were treated with a combination of fragmentation and aspiration, only aspiration, or only fragmentation, and with catheter-directed thrombolytic therapy.

Results

The saturation was improved following treatment in all patients, except in one where the procedure could not be completed. There were no immediate or late procedure-related complications.

Conclusions

Endovascular treatment of severe PE is a safe and efficient option in patients with failing effect or contraindication to systemic thrombolysis.

Bioinformatics-based study to detect chemical compounds that show potential as treatments for pulmonary thromboembolism

The objectives of the present study comprised the recognition of major genes related to pulmonary thromboembolism (PTE) and the evaluation of their functional enrichment levels, in addition to the identification of small chemical molecules that may offer potential for use in PTE treatment. The RNA expression profiling of GSE84738 was obtained from the Gene Expression Omnibus database. Following data preprocessing, the differently expressed genes (DEGs) between the PTE group and the control group were identified using the Linear Models for Microarray package. Subsequently, the protein‑protein interaction (PPI) network of these DEGs was examined using the Search Tool for the Retrieval of Interacting Genes/Proteins database, visualized via Cytoscape. The most significantly clustered modules in the network were identified using Multi Contrast Delayed Enhancement, a plugin of Cytoscape. Subsequently, functional enrichment analysis of the DEGs was performed, using the Database for Annotation Visualization and Integrated Discovery tool. Furthermore, the chemical‑target interaction networks were investigated using the Comparative Toxicogenomics Database as visualized via Cytoscape. A total of 548 DEGs (262 upregulated and 286 downregulated) were identified in the PTE group, compared with the control group. The upregulated and downregulated genes were enriched in Gene Ontology terms related to inflammation and eye sarcolemma, respectively. Tumor necrosis factor (TNF) and erb‑b2 receptor tyrosine kinase 2 (ERBB2) were upregulated genes that ranked higher in the PPI network (47 and 40 degrees, respectively) whereas C‑JUN was the most downregulated gene (46). Small chemical molecules ethinyl (135), cyclosporine (126), thrombomodulin precursor (113) and tretinoin (111) had >100 degrees in the DEG‑chemical interaction network. In addition, ethinyl targeted to TNF, whereas TNF and ERBB2 were targeted by cyclosporine, and tretinoin was a targeted chemical of ERBB2. Therefore, cyclosporine, ethinyl, and tretinoin may be potential targets for PTE treatment.

Tissue perfusion alterations correlate with mortality in patients admitted to the intensive care unit for acute pulmonary embolism: An observational study

We aimed to assess the relationship between alterations of tissue perfusion parameters at admission (highly predictive of mortality in septic shock) and outcome in patients admitted to the intensive care unit (ICU) for acute pulmonary embolism (PE). We conducted a retrospective study to analyze the association between arterial lactate level, skin mottling and urinary output, and 28-day mortality.Over a 22-year period, 317 patients with PE were identified but we finally analyzed 108 patients whose main diagnosis for ICU admission was acute PE. At admission, the sequential organ failure assessment score was 2 (0-6) and the simplified acute physiology score II was 29 (16-43). Thirty patients (28%) received vasopressors and 37 patients (34%) received thrombolytic therapy. Day 28 mortality rate was 25% (n = 27). When compared to 28-day survivors, nonsurvivor patients had higher lactate level (4.5 [2.3-10.3] mmol/L vs 1.4 [1-2.9] mmol/L, P < .0001), more frequent mottling around the knee area (56% vs 25%, P = .003) and a lower urinary output (during the first 6 hours) (0.35 [0-1] mL/kg/h vs. 0.88 [0.62-1.677] mL/kg/h, P = .0002). Mortality increased with the number of tissue perfusion alterations present upon admission, 8% for none, 21% for 1, 28% for 2, and finally reached 85% for 3 tissue perfusion alterations (P < .0001). In a multivariate analysis, the relationship between the number of tissue perfusion alterations and 28-day mortality was maintained after adjustment on the presence of shock and right ventricular dilation at admission.In ICU patients admitted for acute PE, tissue perfusion alterations correlated with 28-day mortality independently of blood pressure and right ventricular dilation.

Comparison between Negative T waves characteristics in acute coronary syndrome and pulmonary embolism

BACKGROUND

Electrocardiogram (ECG) is the first available modality used in patients with chest pain and dyspnea in emergency rooms. We aimed to study differences between acute coronary syndrome (ACS) and acute pulmonary embolism (APE) in patients presented primarily with abnormal negative T waves on their admission Electrocardiogram.

METHODS

This research was a retrospective study in which 297 patients (97 patients with APE and 200 with ACS) were included. The patients were admitted to the emergency ward of a tertiary heart center between 2015 and 2017. In addition to the evaluation of distribution of negative T waves, the depth of the inverted precordial T waves was measured.

RESULTS

The mean age of patients was 62.0 ± 11.4 in ACS group and 60.7 ± 17.6 in APE group (P value = 0.563). Total negative T in V3 and V4 in ACS and APE groups was 9.1 mm and 4.2 mm respectively (P value <0.001). Total magnitude of negative T in anterior leads divided by total magnitude of negative T in inferior leads for ACS and APE groups were 15.1 ± 12.0 and 5.4 ± 3.6 respectively (P value = 0.001). ROC curves showed that total magnitude of negative T in V4 divided by negative T in V1 can be valuable. A cutoff point of 1.75 with sensitivity of 73.5% and specificity of 84.9% (95% CI 0.79-0.91 P < 0.001) could differentiate APE patients from ACS patients.

CONCLUSION

This study suggests that total magnitude of negative T in left precordial leads divided by right precordial leads can be valuable in differentiating APE from ACS.

A new dataset of computed-tomography angiography images for computer-aided detection of pulmonary embolism

The lack of publicly available datasets of computed-tomography angiography (CTA) images for pulmonary embolism (PE) is a problem felt by physicians and researchers. Although a number of computer-aided detection (CAD) systems have been developed for PE diagnosis, their performance is often evaluated using private datasets. In this paper, we introduce a new public dataset called FUMPE (standing for Ferdowsi University of Mashhad's PE dataset) which consists of three-dimensional PE-CTA images of 35 different subjects with 8792 slices in total. For each benchmark image, two expert radiologists provided the ground-truth with the assistance of a semi-automated image processing software tool. FUMPE is a challenging benchmark for CAD methods because of the large number (i.e., 3438) of PE regions and, more especially, because of the location of most of them (i.e., 67%) in lung peripheral arteries. Moreover, due to the reporting of the Qanadli score for each PE-CTA image, FUMPE is the first public dataset which can be used for the analysis of mortality and morbidity risks associated with PE. We also report some complementary prognosis information for each subject.

Determinants of in-hospital clinical outcome in patients with sub-massive pulmonary embolism

Introduction

There is limited data regarding in hospital determinants of clinical deterioration and outcome in sub massive pulmonary embolism (PE). We aimed to evaluate these determinants by comparing biomarkers, CT pulmonary angiogram echocardiography, electrocardiography variables.

Methods

57 patients of sub massive PE diagnosed on CT pulmonary angiogram were included. All patients received UFH on admission and were divided into two groups based on their clinical course. Group 1 comprised of patients who remained stable, group 2 of patients who showed signs of clinical deterioration.

Results

There were 34(59.6%) patients in group 1 and 23(40.4%) patients in group 2. No significant difference in age, gender, BMI. 59.37% had sub massive PE, 5.26% had mortality and 40.4% had clinical deterioration. Intravenous UFH infusion given to 59.6%, systemic thrombolysis 22.8%, catheter directed mechanical breakdown 14%, surgical embolectomy in 3.5% patients. S1Q3T3, new onset RBBB, T wave inversion > 1.63 mm, Basal RV size > 40 mm, RV: LV ratio > 1.2, Global RV longitudinal strain <−10.75% and RVSP > 39 mmHg profiled high risk group. Serum BNP and CT pulmonary angiogram derived scores didn’t differ significantly although CT findings helped to exclude low risk patients (specificity 88%, sensitivity 95%).

Conclusions

Physicians should be aware that patients who have ECG and Echocardiography changes suggestive of right ventricular strain and dysfunction above the cut off values and have documented thrombus in Proximal branches (RPA/LPA) or in distal portion of main pulmonary artery may require aggressive management with systemic/catheter based thrombolysis besides routine anticoagulation with heparin to prevent clinical deterioration.

Reperfusion in acute pulmonary thromboembolism

Acute pulmonary thromboembolism (APTE) is a highly prevalent condition (104-183 cases per 100,000 person-years) and is potentially fatal. Approximately 20% of patients with APTE are hypotensive, being considered at high risk of death. In such patients, immediate lung reperfusion is necessary in order to reduce right ventricular afterload and to restore hemodynamic stability. To reduce pulmonary vascular resistance in APTE and, consequently, to improve right ventricular function, lung reperfusion strategies have been developed over time and widely studied in recent years. In this review, we focus on advances in the indication and use of systemic thrombolytic agents, as well as lung reperfusion via endovascular and classical surgical approaches, in APTE.

Epidemiology, Pathophysiology, and Natural History of Pulmonary Embolism

Pulmonary embolism (PE) is a common and potentially deadly form of venous thromboembolic disease. It is the third most common cause of cardiovascular death and is associated with multiple inherited and acquired risk factors as well as advanced age. The prognosis from PE depends on the degree of obstruction and hemodynamic effects of PE and understanding the pathophysiology helps in risk-stratifying patients and determining treatment. Though the natural history of thrombus is resolution, a subset of patients have chronic residual thrombus, contributing to the post-PE syndrome.

Patient Assessment: Clinical Presentation, Imaging Diagnosis, Risk Stratification, and the Role of Pulmonary Embolism Response Team

Pulmonary embolism (PE) is currently the third leading cause of death and moreover is likely underdiagnosed. PE remains the most common preventable cause of hospital deaths in the United States, which may be attributable to its diagnostic challenges. Although difficult to diagnose, patient mortality rates are time-dependent, and thus, the suspicion and diagnosis of PE in a timely manner is imperative. Diagnosis based on several criteria which may dictate imaging workup as well as laboratory tests and clinical parameters are discussed. The evolution of treatment guidelines via various clinical trials and recommendations is outlined, setting the stage for the use of fibrinolytics, whether systemic or catheter directed. Treatment, including fibrinolytics, is predicated on patient triage into three large categories-massive, submassive, or low-risk PE. Additionally, a relatively new concept of a multidisciplinary team composed of several subspecialty experts known as the PE response team (PERT) is discussed. PERT's timely and unified recommendations have been shown to optimize care and decrease mortality while tailoring treatment to each individual afflicted by PE.

Successful Point-Of-Care Ultrasound-Guided Treatment of Submassive Pulmonary Embolism

Pulmonary embolism is associated with significant mortality and impaired long-term functional outcomes. Timely identification and treatment is crucial for successful management. Unfortunately, prompt diagnosis can be challenging in patients without overt signs of cardiovascular compromise. Point-of-care cardiac ultrasound (POCCUS) can be used to identify signs of acute pulmonary embolism, risk stratify patients for adverse outcomes and assess response to therapy. This report describes a patient with submassive pulmonary embolism and evidence of acute right ventricular strain on POCCUS successfully treated with thrombolytic therapy. The dynamic changes observed on point-of-care ultrasound are presented.

Acute Pulmonary Embolism: Focus on the Clinical Picture

Acute pulmonary embolism (APE) is characterized by numerous clinical manifestations which are the result of a complex interplay between different organs; the symptoms are therefore various and part of a complex clinical picture. For this reason, it may not be easy to make an immediate diagnosis. This is a comprehensive review of the literature on all the various clinical pictures in order to help physicians to promptly recognize this clinical condition, remembering that our leading role as cardiologists depends on and is influenced by our knowledge and working methods.

Ruling out Pulmonary Embolism in Patients with High Pretest Probability

Introduction

The American College of Emergency Physicians guidelines recommend more aggressive workup beyond imaging alone in patients with a high pretest probability (PTP) of pulmonary embolism (PE). However, the ability of multiple tests to safely rule out PE in high PTP patients is not known. We sought to measure the ability of negative computed tomography pulmonary angiography (CTPA) along with negative D-dimer to rule out PE in these high-risk patients.

Methods

We analyzed data from a previous prospective observational study conducted in 12 emergency departments (ED). Wells score criteria were entered by providers before final PE testing. PE was diagnosed by imaging on the index ED visit, or within 45 days, demonstrating either PE or deep vein thrombosis (DVT), or if the patient died of PE during the 45-day, follow-up period. Testing threshold was set at 1.8%.

Results

A total of 7,940 patients were enrolled and tested for PE, and 257 had high PTP (Wells >6). Sixteen of these high-risk patients had negative CTPA and negative D-dimer, of whom two were positive for PE (12.5% [95% confidence interval {2.2%–40.0%}]). One of these patients had a DVT on CT venogram and the other was diagnosed at follow-up.

Conclusion

Our analysis suggests that in patients with high PTP of PE, neither negative CTPA by itself nor a negative CTPA plus a negative D-dimer are sufficient to rule out PE. More aggressive workup strategies may be required for these patients.

Diagnosis and Thrombolytic Management of Massive Intraoperative Pulmonary Embolism Guided by Point of Care Transthoracic Echocardiography

Perioperative pulmonary embolism can go undetected until the sudden onset of cardiopulmonary collapse. Point of care echocardiography in such setting can narrow the differential diagnosis of precipitous instability and facilitate tailored, rather than empiric, therapy in the event of a massive pulmonary embolism. We describe the diagnosis and successful multidisciplinary management of intraoperative massive pulmonary embolism aided by both transthoracic and transesophageal echocardiography. Key aspects regarding the classification and treatment of pulmonary embolism are subsequently reviewed.

Management of patients with high-risk pulmonary embolism: a narrative review

High-risk pulmonary embolism (PE) is a life-threatening disorder associated with high mortality and morbidity. Most deaths in patients with shock occur within the first few hours after presentation, and rapid diagnosis and treatment is therefore essential to save patients’ lives. The main manifestations of major PE are acute right ventricular (RV) failure and hypoxia. RV pressure overload is predominantly related to the interaction between the mechanical pulmonary vascular obstruction and the underlying cardiopulmonary status. Computed tomography angiography allows not only adequate visualization of the pulmonary thromboemboli down to at least the segmental level but also RV enlargement as an indicator of RV dysfunction. Bedside echocardiography is an acceptable alternative under such circumstances. Although it does not usually provide a definitive diagnosis or exclude pulmonary embolism, echocardiography can confirm or exclude severe RV pressure overload and dysfunction. Extracorporeal membrane oxygenation support can be an effective procedure in patients with PE-induced circulatory collapse. Thrombolysis is generally accepted in unstable patients with high-risk PE; however, thrombolytic agents cannot be fully administered to patients with a high risk of bleeding. Conversely, catheter-directed treatment is an optimal treatment strategy for patients with high-risk PE who have contraindications for thrombolysis and is a minimally invasive alternative to surgical embolectomy. It can be performed with a minimum dose of thrombolytic agents or without, and it can be combined with various procedures including catheter fragmentation or embolectomy in accordance with the extent of the thrombus on a pulmonary angiogram. Hybrid catheter-directed treatment can reduce a rapid heart rate and high pulmonary artery pressure and can improve the gas exchange indices and outcomes. Surgical embolectomy is also performed in patients with contraindications for or an inadequate response to thrombolysis. Large hospitals having an intensive care unit should preemptively establish diagnostic and therapeutic protocols and rehearse multidisciplinary management for patients with high-risk PE. Coordination with a skilled team comprising intensivists, cardiologists, cardiac surgeons, radiologists, and other specialists is crucial to maximize success.

Use of the d-dimer for Detecting Pulmonary Embolism in the Emergency Department

BACKGROUND

Assessment for pulmonary embolism (PE) in the emergency department (ED) remains complex, involving clinical decision tools, blood tests, and imaging.

OBJECTIVE

Our objective was to examine the test characteristics of the high-sensitivity d-dimer for the diagnosis of PE at our institution and evaluate use of the d-dimer and factors associated with a falsely elevated d-dimer.

METHODS

We retrospectively collected data on adult patients evaluated with a d-dimer and computed tomography (CT) pulmonary angiogram or ventilation perfusion scan at two EDs between June 4, 2012 and March 30, 2016. We collected symptoms (dyspnea, unilateral leg swelling, hemoptysis), vital signs, and medical and social history (cancer, recent surgery, medications, history of deep vein thrombosis or PE, chronic obstructive pulmonary disease, smoking). We calculated test characteristics, including sensitivity, specificity, and likelihood ratios for the assay using conventional threshold and with age adjustment, and performed a univariate analysis.

RESULTS

We found 3523 unique visits with d-dimer and imaging, detecting 198 PE. Imaging was pursued on 1270 patients with negative d-dimers, revealing 9 false negatives, and d-dimer was sent on 596 patients for whom negative Pulmonary Embolism Rule-Out Criteria (PERC) were documented with 2% subsequent radiographic detection of PE. The d-dimer showed a sensitivity of 95.7% (95% confidence interval [CI] 91-98%), specificity of 40.0% (95% CI 38-42%), negative likelihood ratio of 0.11 (95% CI 0.06-0.21), and positive likelihood ratio of 1.59 (95% CI 1.53-1.66) for the radiographic detection of PE. With age adjustment, 347 of the 2253 CT scans that were pursued in patients older than 50 years with an elevated d-dimer could have been avoided without missing any additional PE. Many risk factors, such as age, history of PE, recent surgery, shortness of breath, tachycardia and hypoxia, elevated the d-dimer, regardless of the presence of PE.

CONCLUSIONS

Many patients with negative d-dimer and PERC still received imaging. Our data support the use of age adjustment, and perhaps adjustment for other factors seen in patients evaluated for PE.

Value of CT pulmonary angiography to predict short-term outcome in patient with pulmonary embolism

To evaluate the role of CT pulmonary angiography (CTPA) in the assessment of pulmonary embolism (PE) severity and the related CT cardiac changes, reflecting the clinical status of the patients and predicting the outcome. A prospective study of 184 patients presented with suspicious acute PE. All patients underwent CTPA followed by ECHO. Pulmonary artery obstructive index (PAOI) using Qanadli Score was calculated and cardiac changes recorded. The patients' outcome was followed up for 30 days. Only 150 patients completed the study; 26.7% needed ICU admission while 13.3% died during follow-up. There was a significant relationship between the PAOI and the risk classification, right ventricular dysfunction (RVD) diagnosed by ECHO and the patients' short outcome. We found PAOI cut off value 45% for mortality and 35% for ICU admission and 27.5% for RVD with 60, 75 and 90% sensitivity and 80, 73.3 and 68.6% specificity respectively. CT RV/LV ratio was the most sensitive parameter to predict RV dysfunction followed by pulmonary artery diameter. CTPA is not only used for diagnosis but also to assess the severity of PE, the effect on the right ventricular function and subsequently the need for ICU admission and prediction of the outcome.

Direct oral anticoagulants in the treatment of pulmonary embolism

OBJECTIVE

The objective of this review is to examine the management strategies for pulmonary embolism (PE) with an emphasis of the role of direct oral anticoagulants (DOACs).

METHODS

PubMed was searched to identify relevant journal articles published through April 2017. Additional references were obtained from articles discovered during the database search.

RESULTS

Initial heparinization followed by long-term anticoagulation with vitamin K antagonists has been considered the mainstay for the treatment of PE. However, DOACs now offer comparably effective and potentially safer alternatives for both acute and long-term treatment of PE using a monotherapy approach without the need for initial heparinization for rivaroxaban or apixaban. Advantages to using DOACs include oral availability, rapid onset of action, minimal drug and food interactions, predictable pharmacokinetics, and lack of need for routine monitoring. Limitations of using these agents include a limited availability of assays to quickly and efficiently measure their anticoagulant effects and the lack of widely available reversal agents for the direct oral factor Xa inhibitors; although idarucizumab has recently been approved for the reversal of dabigatran's anticoagulant effects.

CONCLUSIONS

Advantages to using DOACs render them an attractive alternative to conventional therapy in PE treatment that may simplify acute and long-term treatment paradigms, improve patient outcomes, and increase patient compliance. However, questions remain pertaining to the use of DOACs in PE patients with high-risk features and in cancer patients and fragile populations. Clinical studies are under way to address many of these issues.

Diagnostic Accuracy of Point-of-Care Ultrasound Performed by Pulmonary Critical Care Physicians for Right Ventricle Assessment in Patients With Acute Pulmonary Embolism

OBJECTIVES

Risk stratification for acute pulmonary embolism using imaging presence of right ventricular dysfunction is essential for triage; however, comprehensive transthoracic echocardiography has limited availability. We assessed the accuracy and timeliness of Pulmonary Critical Care Medicine Fellow's performance of goal-directed echocardiograms and intensivists' interpretations for evaluating right ventricular dysfunction in acute pulmonary embolism.

DESIGN

Prospective observational study and retrospective chart review.

SETTING

Four hundred fifty bed urban teaching hospital.

PATIENTS

Adult in/outpatients diagnosed with acute pulmonary embolism.

INTERVENTIONS

Pulmonary critical care fellows performed and documented their goal-directed echocardiogram as normal or abnormal for right ventricular size and function in patients with acute pulmonary embolism. Gold standard transthoracic echocardiography was performed on schedule unless the goal-directed echocardiogram showed critical findings. Attending intensivists blinded to the clinical scenario reviewed these exams at a later date.

MEASUREMENTS AND MAIN RESULTS

Two hundred eighty-seven consecutive patients were evaluated for acute PE. Pulmonary Critical Care Medicine Fellows performed 154 goal-directed echocardiograms, 110 with complete cardiology-reviewed transthoracic echocardiography within 48 hours for comparison. Pulmonary Critical Care Medicine Fellow's area under the curve for size and function was 0.83 (95% CI, 0.75-0.90) and 0.83 (95% CI, 0.75-0.90), respectively. Intensivists' 1/2 area under the curve for size and function was (1) 0.87 (95% CI, 0.82-0.94), (1) 0.87 (95% CI, 0.80-0.93) and (2) 0.88 (95% CI, 0.82-0.95), (2) 0.88 (95% CI, 0.82-0.95). Median time difference between goal-directed echocardiogram and transthoracic echocardiography was 21 hours 18 minutes.

CONCLUSIONS

This is the first study to evaluate pulmonary critical care fellows' and intensivists' use of goal-directed echocardiography in diagnosing right ventricular dysfunction in acute pulmonary embolism. Pulmonary Critical Care Medicine Fellows and intensivists made a timely and accurate assessment. Screening for right ventricular dysfunction using goal-directed echocardiography can and should be performed by pulmonary critical care physicians in patients with acute pulmonary embolism.

Multiple cardiac arrests induced by pulmonary embolism in a traumatically injured patient: A case report and review of the literature

RATIONALE

Pulmonary embolism-induced cardiac arrest should not be given up arbitrarily, knowing that the etiology of pulmonary embolism is reversible in most cases.

PATIENT CONCERNS

We present a case of continuous resuscitation lasting approximately 4 hours, during which 21 episodes of cardiac arrest occurred in a 46-year-old man who sustained high-level paraplegia after a road traffic accident.

DIAGNOSES

Multiple cardiac arrests induced by pulmonary embolism.

INTERVENTIONS

The patient received cardiopulmonary resuscitation and thrombolytic therapy.

OUTCOMES

The patient was discharged in 2 weeks when his condition turned for the better.

LESSONS

Cardiopulmonary resuscitation of patients with pulmonary embolism-induced cardiac arrest should not be given up arbitrarily, knowing that the etiology of pulmonary embolism is reversible in most cases. Effective external cardiac compression can not only save the patient's life but also attenuate neurological sequelae. Thrombolytic therapy is the key to the final success of resuscitation.

Effectiveness of prognosticating pulmonary embolism using the ESC algorithm and the Bova score

The prognostic value of the European Society of Cardiology (ESC) 2014 algorithm and the Bova score has lacked adequate validation. According to the ESC 2014 guidelines and the Bova score, we retrospectively risk stratified normotensive patients with PE who were enrolled in the PROTECT study. This study used a complicated course (which consisted of death from any cause, haemodynamic collapse, or recurrent PE) as the primary endpoint, and follow-up occurred through 30 days after the PE diagnosis. Of 848 patients, 37 % had a sPESI of 0 and 5 (1.6 %; 95 % confidence interval [CI], 0.5-3.7 %) experienced a complicated course. Of 143 patients with a sPESI of 0 points and negative computed tomographic pulmonary angiography (CTPA) for right ventricle (RV) dysfunction, three (2.1 %; 95 % CI, 0.4-6.0 %) experienced a complicated course. Four hundred seventy-eight (56 %) patients with a sPESI ≥ 1 had echocardiographic evidence of RV dysfunction or elevated troponin level or none, and 48 (10 %, 95 % CI, 7.5-13.1 %) experienced a complicated course. Fifty-seven (6.7 %) patients with a sPESI ≥ 1 had echocardiographic RV dysfunction and elevated troponin level, and 10 (17.5 %; 95 % CI, 8.8-29.9 %) experienced a complicated course, compared to 21.6 % (8 of 37 patients, 21.6 %; 95 % CI, 9.8-38.2 %) in Bova risk class III. In conclusion, the ESC 2014 prognostic algorithm is effective in the risk stratification of normotensive patients with PE. Use of CTPA did not improve the ability for identification of low-risk PE. Bova risk scoring did not significantly improve identification of intermediate-high risk PE.

Jiménez et al. Validation of the ESC 2014 prognostication algorithm

Automated volumetric analysis of four cardiac chambers in pulmonary embolism

Identification of patients with acute pulmonary embolism (PE) who might be at risk of circulatory collapse by using a fast, automated system is highly desired. It was our objective to investigate whether automated cardiac volumetric analysis following computerised tomographic pulmonary angiography (CTPA) is useful to identify increased clot load and adverse prognosis in patients with acute PE. We retrospectively analysed a consecutive series of non-gated CTPA studies of 124 patients with acute PE and 43 controls. Right and left ventricular diameters (RV/LV) were measured on four-chamber view, while each cardiac chamber underwent automatic volumetric measurements. Findings were correlated to the pulmonary arterial obstruction index (PAOI). Outcome was expressed by admission to an intensive care unit (ICU) or mortality within 30 days. There was a significant positive correlation between the PAOI and the volumes of the right side cavities (r=0.25 for the atrium and r=0.49 for the ventricle), and between the right-to-left atrial and ventricular volume ratios (r=0.49 and r=0.57, respectively). Results for the combined outcome of mortality or ICU admission that fell in the upper tertile of the right atrial and right ventricular volumes yielded hazard ratios of 3.9 and 3.3, respectively, compared to those in the lower tertile. RV/LV diameter ratio did not correlate with outcome. In conclusion, adverse outcome and significant pulmonary clot load in patients with acute PE are associated with a volume shift towards right heart cavities, which correlates to prognosis better than the CT-measured RV/LV diameter ratio, suggesting the advantage of using fast fully automatic volumetric analysis to identify patients at risk.

Catheter-Directed Therapy for Pulmonary Embolism: Patient Selection and Technical Considerations

Acute pulmonary embolism (PE) is the third most common cause of death among hospitalized patients. Treatment escalation beyond anticoagulation therapy is necessary in patients with cardiogenic shock and may be of benefit in select normotensive patients with right heart strain. Percutaneous catheter-based techniques (catheter-directed mechanical thrombectomy, clot maceration, and/or pharmacologic thrombolysis) as an alternative or adjunct to systemic thrombolysis can rapidly debulk central clot in patients with shock. Catheter-directed thrombolysis, which uses a low-dose intraclot prolonged thrombolytic infusion, is a promising but insufficiently studied therapy for patients presenting with acute intermediate-risk PE.

Catheter-directed therapy as a treatment for submassive pulmonary embolism: A meta-analysis

AIMS

Catheter-directed therapy (CDT) is included in the guidelines for diagnosing and treating massive pulmonary embolism. However, few studies have evaluated the efficacy of CDT as a treatment for submassive pulmonary embolism (SPE). Therefore, we used evidence-based medicine to evaluate the effectiveness and safety of CDT in treating SPE.

METHODS

Search terms describing CDT in SPE and patients with intermediate pulmonary embolism were entered into the PubMed, Embase and Cochrane Library databases to identify relevant articles without language restrictions published between January 1990 and December 2016. A quality assessment and data extraction were performed by two investigators. The clinical efficacy of and major complications associated with treatment were analysed using a fixed effects model.

KEY FINDINGS

A total of 552 patients in 16 studies were included in this meta-analysis. The clinical success rate in CDT was approximately 100% (95% confidence interval (CI): 99%, 100%), the primary bleeding rate was 0.02% (95% CI: 0%, 0.05%), and mortality during hospitalization was approximately 0% (95% CI: 0%, 0.01%). The mean decrease in pulmonary artery systolic pressure after treatment was -14.9% (95% CI: -19.25%, -10.55%), and the mean post-treatment change in the ratio of the right to the left ventricle (RV/LV) was -0.35% (95% CI: -0.48%, -0.22%).

SIGNIFICANCE

CDT is effective and safe as a treatment for SPE and could be a first-line treatment for SPE under specific conditions.

Saddle vs Nonsaddle Pulmonary Embolism: Clinical Presentation, Hemodynamics, Management, and Outcomes

OBJECTIVE

To understand the clinical significance, hemodynamic presentation, management, and outcomes of patients presenting with saddle pulmonary embolism (PE).

METHODS

All patients with saddle PE diagnosed at Mayo Clinic in Rochester, Minnesota, from January 1, 1999, through December 31, 2014, were included in this study. These patients were age and simplified Pulmonary Embolism Severity Index (sPESI) matched (1:1) to a nonsaddle PE cohort. Both groups were then classified into massive, submassive, and low-risk PE based on established criteria and compared for clinical presentation, management, and outcomes.

RESULTS

A total of 187 consecutive patients with saddle PE were identified. The saddle PE group presented more frequently with massive PE (31% vs 20%) and submassive PE (49% vs 32%), whereas low-risk PE was more common in the nonsaddle PE group (48% vs 20%). Systemic thrombolysis was used more frequently in the saddle PE group on admission (10% vs 4%; P=.04) and later during hospitalization (3.2% vs 0%; P=.03). Late major adverse events were similar in both groups except for mechanical ventilation (6% in saddle PE vs 1% in nonsaddle PE; P=.02). Overall in-hospital mortality did not differ between the 2 groups (4.3% in saddle PE vs 5.4% in nonsaddle PE; P=.81).

CONCLUSION

Although patients with saddle PE presented with higher rates of hemodynamic compromise and need for thrombolysis and mechanical ventilation, we found no difference in short-term outcomes compared with an age- and severity-matched nonsaddle PE cohort. Overall, in-hospital mortality was low in both groups.