Role of clinical and pulmonary computed tomography angiographic parameters in the prediction of short- and long-term mortality in patients with pulmonary embolism

MRA as the Preferred Test for Pulmonary Embolism During the Iodinated Contrast Media Shortage of 2022: A Single-Center Experience

BACKGROUND. Closure of a GE Healthcare facility in Shanghai, China, in 2022 disrupted the iodinated contrast media supply. Technologic advances have addressed limitations associated with the use of pulmonary MRA for diagnosis of pulmonary embolism (PE). OBJECTIVE. The purpose of this study was to describe a single institution's experience in the use of pulmonary MRA as an alternative to CTA for the diagnosis of PE in the general population during the iodinated contrast media shortage in 2022. METHODS. This retrospective single-center study included all CTA and MRA examinations performed to exclude PE from April 1 through July 31 (18 weekly periods) in 2019 (before the COVID-19 pandemic and contrast media shortage), 2021 (during the pandemic but before the shortage), and 2022 (during both the pandemic and the shortage). From early May through mid-July of 2022, MRA served as the preferred test for PE diagnosis, to preserve iodinated contrast media. CTA and MRA reports were reviewed. The total savings in iodinated contrast media volume resulting from preferred use of MRA was estimated. RESULTS. The study included 4491 examinations of 4006 patients (mean age, 57 ± 18 [SD] years; 1715 men, 2291 women): 1245 examinations (1111 CTA, 134 MRA) in 2019, 1547 examinations (1403 CTA, 144 MRA) in 2021, and 1699 examinations (1282 CTA, 417 MRA) in 2022. In 2022, the number of MRA examinations was four (nine when normalized to a 7-day period) in week 1, and this number increased to a maximum of 63 in week 10 and then decreased to 10 in week 18. During weeks 8-11, more MRA examinations (range, 45-63 examinations) than CTA examinations (range, 27-46 examinations) were performed. In 2022, seven patients with negative MRA underwent subsequent CTA within 2 weeks; CTA was negative in all cases. In 2022, 13.9% of CTA examinations (vs 10.3% of MRA examinations) were reported as having limited image quality. The estimated 4-month savings resulting from preferred use of MRA in 2022, under the assumption of uniform simple linear growth in CTA utilization annually and a CTA dose of 1 mL/kg, was 27 L of iohexol (350 mg I/mL). CONCLUSION. Preferred use of pulmonary MRA for PE diagnosis in the general population helped to conserve iodinated contrast media during the 2022 shortage. CLINICAL IMPACT. This single-center experience shows pulmonary MRA to be a practical substitute for pulmonary CTA in emergency settings.

Intermediate-Risk Pulmonary Embolism: A Review of Contemporary Diagnosis, Risk Stratification and Management

Pulmonary embolism (PE) can have a wide range of hemodynamic effects, from asymptomatic to a life-threatening medical emergency. Pulmonary embolism (PE) is associated with high mortality and requires careful risk stratification for individualized management. PE is divided into three risk categories: low risk, intermediate-risk, and high risk. In terms of initial therapeutic choice and long-term management, intermediate-risk (or submassive) PE remains the most challenging subtype. The definitions, classifications, risk stratification, and management options of intermediate-risk PE are discussed in this review.

Risk stratification to optimize the management of acute pulmonary embolism

INTRODUCTION

Pulmonary embolism (PE) is a life-threatening disease. Risk stratification in patients with acute PE can guide clinical decisions. Clinical assessment, including hemodynamics, respiratory parameters, patient history, and right ventricle evaluation, has a pivotal role in this scope.

AREAS COVERED

This review aims to describe: i) the role of individual tools for prognostic stratification, from simple clinical parameters to the models suggested by international guidelines; ii) the implications of risk stratification in terms of patient disposition and treatment. The bleeding risk assessment in acute PE was also reviewed. The literature search was performed in PubMed and Embase to address these issues.

EXPERT OPINION

Prognostic assessment is essential to proceed with life-saving treatments in hemodynamically unstable patients and consider home treatment or short hospital stay in patients at low risk for death. In hemodynamically stable patients, risk stratification allows the implementation of personalized treatment pathways to reduce the risk of death, early PE recurrence, and bleeding. With the aim of optimizing healthcare resources, risk stratification may suggest appropriate patient disposition.

Submassive Pulmonary Embolism: Current Perspectives and Future Directions

Submassive pulmonary embolism (PE) lies on a spectrum of disease severity between standard and high-risk disease. By definition, patients with submassive PE have a worse outcome than the majority of those with standard-risk PE, who are hemodynamically stable and lack imaging or laboratory features of cardiac dysfunction. Systemic thrombolytic therapy has been proven to reduce mortality in patients with high-risk disease; however, its use in submassive PE has not demonstrated a clear benefit, with haemodynamic improvements being offset by excess bleeding. Furthermore, meta-analyses have been confusing, with conflicting results on overall survival and net gain. As such, significant interest remains in optimising thrombolysis, with recent efforts in catheter-based delivery as well as upcoming studies on reduced systemic dosing. Recently, long-term cardiorespiratory limitations following submassive PE have been described, termed post-PE syndrome. Studies on the ability of thrombolytic therapy to prevent this condition also present conflicting evidence. In this review, we aim to clarify the current evidence with respect to submassive PE management, and also to highlight shortcomings in current definitions and prognostic factors. Additionally, we discuss novel therapies currently in preclinical and early clinical trials that may improve outcomes in patients with submassive PE.

Prognostic significance of computed tomography-assessed right ventricular enlargement in low-risk patients with pulmonary embolism: Systematic review and meta-analysis

BACKGROUND

For patients with acute low-risk pulmonary embolism (PE), determined by a validated clinical prognostic score, the additive prognostic significance of computed tomography (CT)-assessed right ventricular (RV) enlargement is uncertain.

METHODS

We performed a systematic review and meta-analysis of studies that enrolled patients with acute low-risk PE to assess the prognostic value of concomitant CT-assessed RV enlargement for 30-day all-cause mortality and PE-related death. We conducted unrestricted searches of PubMed and Embase through December 2019. We used a random-effects model to pool study results; Begg rank correlation method to evaluate for publication bias; and I² testing to assess for heterogeneity.

RESULTS

Of the 7 cohorts with 2197 participants who had low-risk PE and provided results on the primary outcome, 743 (34%; 95% confidence interval [CI], 32-36%) patients had concomitant RV enlargement. Six of 743 (0.8%; 95% CI, 0.3-1.8%) patients with concomitant RV enlargement died 30-days after the diagnosis of PE compared with 3 of 1454 (0.2%, 95% CI, 0-0.6%) without RV enlargement. CT-assessed RV enlargement did not have a significant association with 30-day all-cause mortality (odds ratio [OR], 2.6; 95% CI, 0.7-9.4; I² = 0%; P = 0.15) or PE-related mortality (OR, 2.8; 95% CI, 0.7-12.1; I² = 0%; P = 0.16).

CONCLUSIONS

CT-assessed RV enlargement occurs in a third of PE patients identified as low-risk by clinical scores. Mortality rate in these patients is low, and CT-assessed RV enlargement was not associated with a significantly increased risk of death within 30 days of PE diagnosis.

Definitions, adjudication, and reporting of pulmonary embolism-related death in clinical studies: A systematic review

BACKGROUND

Pulmonary embolism (PE)-related death is a component of the primary outcome in many venous thromboembolism (VTE) studies. The absence of a standardized definition for PE-related death hampers study outcome evaluation and between-study comparisons.

OBJECTIVES

To summarize definitions for PE-related death used in recent VTE studies and to assess the PE-related death rate.

PATIENTS/METHODS

A systematic literature search was conducted on 26 April 2018 from 1 January 2014 up to the search date in MEDLINE, Embase, and CENTRAL. Cohort studies and randomized trials in which PE-related death was included in the primary outcome were eligible. Screening of titles, abstracts, and full-text articles, and data extraction were independently performed in duplicate by two authors. Study outcomes included the definition for PE-related death, VTE case-fatality rate, and death due to PE rate. Descriptive statistics were used to analyze the data.

RESULTS

Of the 6807 identified citations, 83 studies were included of which 27% were randomized trials, 31% were prospective, and 42% retrospective cohort studies. Thirty-five studies (42%) had a central adjudication committee. Thirty-eight (46%) reported a definition for PE-related death of which the most frequently used components were "autopsy-confirmed PE" (50%), "objectively confirmed PE before death" (55%), and "unexplained death" (58%). Median VTE case-fatality rate was 1.8% (interquartile range, 0.0-13).

CONCLUSIONS

Only half of the included studies reported definitions for PE-related death, which were very heterogeneous. Case-fatality rate of VTE events varied widely across studies. Standardization of the definition and guidance on adjudication and reporting of PE-related death is needed.

Prognostic value of cardiovascular parameters in computed tomography pulmonary angiography in patients with acute pulmonary embolism

The value of various computed tomography parameters for prognosis and risk stratification in acute pulmonary embolism is controversial. Our objective was to evaluate the impact of specific cardiovascular computed tomography pulmonary angiography parameters on short- and long-term clinical outcomes.

We analysed radiological and clinical data of 1950 patients with acute pulmonary embolism who participated in an international randomised clinical trial on anticoagulants. Parameters included right/left ventricular ratio, septal bowing, cardiothoracic ratio, diameters of pulmonary trunk and aorta, and intrahepatic/azygos vein contrast medium backflow. Associations with mortality, recurrent venous thromboembolism (VTE), hospitalisation, bleeding and adverse events were assessed over the short term (1 week and 1 month) and long term (12 months).

Pulmonary trunk enlargement was the only parameter significantly associated with mortality over both the short and long term (OR 4.18 (95% CI 1.04–16.76) at 1 week to OR 2.33 (95% CI 1.36–3.97) after 1 year), as well as with recurrent VTE and hospitalisation.

Most of the evaluated radiological parameters do not have strong effects on the short- or long-term outcome in patients with acute pulmonary embolism. Only an enlarged pulmonary trunk diameter carries an increased risk of mortality and recurrent VTE up to 12 months, and can be used for risk stratification.