Safety of multidetector computed tomography pulmonary angiography to exclude pulmonary embolism in patients with a likely pretest clinical probability

Validation of a Recently Developed Fluoroscopic Video Analysis Workstation (Radwisp™) for the Reliable Diagnosis of Acute Pulmonary Thromboembolism

Objective Radwisp™ is a fluoroscopic video analysis workstation recently developed to evaluate pulmonary circulation, thereby obviating the need for contrast medium or breath-holding. This study validated Radwisp as a diagnostic tool for acute pulmonary embolism (APE) and evaluated its potential utility in patients with symptoms of suspected APE. Methods The study included 10 patients (mean age, 69±16 years old) who were admitted to our hospital for suspected APE based on symptoms and physical examination findings between January 2020 and April 2021. Contrast-enhanced computed tomography (CT) and cineradiography, based on standard radiographs for the creation of a Radwisp image, were performed on the same day. Of the 10 cases of suspected APE, 7 were definitively diagnosed by CT with APE, and 3 were definitively diagnosed as not having APE. Fifty physicians (25 cardiologists and 25 residents) were blinded to patient information and CT images and asked to diagnose the presence of APE based solely on the Radwisp images. Results A total of 250 diagnoses were made by cardiologists and 250 by residents. Among the cardiologists, the sensitivity and specificity of the Radwisp-based analysis were 91% and 48%, respectively, and the positive and negative predictive values were 80% and 69%, respectively. Among the residents, the sensitivity and specificity were 88% and 35%, respectively, and the positive and negative predictive values were 76% and 55%, respectively. Conclusion This study showed an initial validation of Radwisp for diagnosing APE, revealing a high sensitivity but not yet achieving a high specificity. Further studies with a larger number of cases are needed to thoroughly evaluate the diagnostic performance.

Prognostic value of echocardiographic indices in risk stratification of intermediate-risk pulmonary embolism

Background

Regarding risk stratification of intermediate-risk pulmonary embolism, data are still not sufficient. Transthoracic echocardiography parameters may be useful in risk evaluation in those patients. Some novel echocardiographic indices mainly tricuspid regurgitation peak gradient (TRPG), pulmonary artery acceleration time, and tricuspid annulus plane systolic excursion (TAPSE) were evaluated showing that they may be used for risk stratification of normotensive cases with acute pulmonary embolism (APE).

Results

The studied cases were subdivided into two classes:

Class I with intermediate-low-risk pulmonary embolism included 32 patients (53.3%) and class II with intermediate high-risk pulmonary embolism involved 28 cases (46.7%). Dyspnea, tachypnea, troponin level, RVD, RVD/LVD, TR velocity, and TRPG/TAPSE were statistically higher in cases of class II than that of class I (p < 0.001). On the other hand, TAPSE and PA acceleration time were markedly lower in the case of class II than that of class I (p < 0.001). Ten cases (35.7%) of group II required thrombolytic agents with a significant difference (p<0.001).

Conclusions

RVD/LVD ratio, TAPSE, TRPG/TAPSE ratio, and PA acceleration time are echocardiographic parameters that might be helpful for risk stratification of cases with moderate-risk pulmonary embolism. The addition of elevated levels of cardiac troponins to imaging and clinical findings can improve PE-related risk identification.

Trial registration

NCT04020250. Registered on 16 July 2019.

PaCO2-EtCO2 Gradient and D-dimer in the Diagnosis of Suspected Pulmonary Embolism

BACKGROUND

The diagnosis of pulmonary embolism (PE) because of nonspecific clinical presentation remains as a challenge for emergency physicians. Arterial to end-tidal partial pressure of carbon dioxide (P(a-Et) CO2) gradient may be useful in the evaluation of PE. This aimed to define the diagnostic role of P(a-Et)CO2 gradient by sidestream capnography, as a noninvasive method, and D-dimer in patients with PE.

MATERIALS AND METHODS

Two hundred and three patients with chest pain or dyspnea who attend the hospital emergency ward were enrolled over a study period at a single academic center. PE was confirmed by multidetector computed tomography (MDCT) scans. PaCO2, EtCO2, and D-dimer were measured within 24 h of MDCT by capnograph.

RESULTS

The combination of P(a-Et)CO2 gradient (cutoff >9.2 ng/ml) and D-dimer (cutoff >3011 ng/ml) with sensitivity and specificity of 30.2% and 87.2% showed a significant diagnostic value in detecting PE (area under the curve = 0.577, P = 0.045) but not alone (P > 0.05).

CONCLUSION

As the results show, the combination of P(a-Et)CO2 gradient and D-dimer can show an acceptable diagnostic value in detecting PE, although it suggests further research on evaluating the diagnostic value of P(a-Et)CO2 gradient and combining it with other diagnostic criteria to achieve a definite and generalizable result.

Diagnostic management of inpatients with a positive D-dimer test: developing a new clinical decision-making rule for pulmonary embolism

Background

A positive D-dimer test has high sensitivity but relatively poor specificity for the diagnosis of pulmonary embolism, causing difficulty for clinicians unskilled in pulmonary embolism diagnosis in determining whether a patient with a positive D-dimer test needs to undergo computed tomographic pulmonary angiography.

Objectives

We sought to develop a new clinical decision-making rule based on a positive D-dimer result to predict the probability of pulmonary embolism and to guide clinicians in making decisions regarding the need for computed tomographic pulmonary angiography.

Methods

We conducted a prospective, multicenter study in three hospitals in China. A total of 3014 inpatients with positive D-dimer results were included. In the derivation group, we built a multivariate logistic regression model and deduced a regression equation from which our score was derived. Finally, we validated the score in an independent cohort.

Results

Our score included nine variables (points): chest pain (1.4), chest tightness (2.3), shortness of breath (3.6), hemoptysis (3.4), heart rate ≥100 beats/min (3.6), blood gas analysis (2.9), electrocardiogram presenting a typical S1Q3T3 pattern (4.1), electrocardiogram findings (2.4), and ultrasonic cardiogram findings (3.7). The sensitivities and specificities were 100% and 86.94%, respectively, in the derivation group and 100% and 90.82%, respectively, in the validation group. Additionally, the observed and predicted proportions of patients who underwent computed tomographic pulmonary angiography were 16.82% and 10.76%, respectively, in the derivation group and 18.72% and 11.40%, respectively, in the validation group.

Conclusions

The new score can categorize inpatients with a positive D-dimer test as pulmonary embolism-likely or pulmonary embolism-unlikely, thus reducing unnecessary computed tomographic pulmonary angiography examinations.

EANM guideline for ventilation/perfusion single-photon emission computed tomography (SPECT) for diagnosis of pulmonary embolism and beyond

These guidelines update the previous EANM 2009 guidelines on the diagnosis of pulmonary embolism (PE). Relevant new aspects are related to (a) quantification of PE and other ventilation/perfusion defects; (b) follow-up of patients with PE; (c) chronic PE; and (d) description of additional pulmonary physiological changes leading to diagnoses of left ventricular heart failure (HF), chronic obstructive pulmonary disease (COPD) and pneumonia. The diagnosis of PE should be reported when a mismatch of one segment or two subsegments is found. For ventilation, Technegas or krypton gas is preferred over diethylene triamine pentaacetic acid (DTPA) in patients with COPD. Tomographic imaging with V/PSPECT has higher sensitivity and specificity for PE compared with planar imaging. Absence of contraindications makes V/PSPECT an essential method for the diagnosis of PE. When V/PSPECT is combined with a low-dose CT, the specificity of the test can be further improved, especially in patients with other lung diseases. Pitfalls in V/PSPECT interpretation are discussed. In conclusion, V/PSPECT is strongly recommended as it accurately establishes the diagnosis of PE even in the presence of diseases like COPD, HF and pneumonia and has no contraindications.

Outcomes following a negative computed tomography pulmonary angiography according to pulmonary embolism prevalence: a meta-analysis of the management outcome studies

Essentials Computed tomographic pulmonary angiography (CTPA) is used to exclude pulmonary embolism. This meta-analysis explores the occurrence of venous thromboembolic events (VTE) after a CTPA. Occurrence of VTE after a negative CTPA is ˜8% in study subgroups with a prevalence of PE ≥ 40%. CTPA may be insufficient to safely rule out VTE as a stand-alone diagnostic test for this subgroup.

SUMMARY

Background Outcome studies have reported the safety of computed tomographic pulmonary angiography (CTPA) as a stand-alone imaging technique to rule out pulmonary embolism (PE). Whether this can be applied to all clinical probabilities remains controversial. Objectives We performed a meta-analysis to determine the proportion of patients with venous thromboembolic events (VTE) despite a negative CTPA according to pretest PE prevalence. Methods We searched MEDLINE, EMBASE and the Cochrane Library (January 1990 to May 2017) for outcome studies recruiting patients with suspected PE using CTPA as a diagnostic strategy. The primary outcome was the cumulative occurrence of VTE at 3 months following a negative CTPA. Results Twenty-two different studies were identified. VTE was confirmed in 2.4% of patients (95% CI, 1.3-3.8%) either at the time of the index event or in the 3 months follow-up. Subgroup analyses suggested that the cumulative occurrence of VTE was related to pretest prevalence of PE, as VTE occurred in 1.8% (95% CI, 0.5-3.7%), 1.4% (95% CI, 0.7-2.3%), 1.0% (95% CI, 0.5-1.8%) and 8.1% (95% CI, 3.5-14.5%) of subgroups of patients with a PE prevalence < 20%, 20-29%, 30-39% and ≥ 40%, respectively. This was further confirmed using meta-regression analysis. Conclusions The negative predictive value of CTPA for VTE varies according to pretest prevalence of PE, and is likely to be insufficient to safely rule out VTE as a stand-alone diagnostic test amongst patients at the highest pretest probability of VTE. Prospective studies are required to validate the appropriate diagnostic algorithm for this subgroup of patients.

Temporal trends in outpatient management of incident pulmonary embolism and associated mortality

INTRODUCTION

In clinical trial settings, outpatient management of pulmonary embolism (PE) is feasible and safe, but less is known on its use in routine care. We determined trends in outpatient management of PE and associated mortality in a large non-select patient population.

METHODS

All residents of Quebec, Canada with a first-ever work-up for suspected PE in the emergency department (ED) over 10years were included. Patients could transition to outpatient management and from unconfirmed to confirmed PE in a time-varying fashion. Comparing the years 2005-9 with 2000-4, we assessed the odds ratio (OR) for outpatient management, and relative risk (RR) for all-cause mortality, readmissions for PE, and major bleeding in 30days. We adjusted the RR for a mortality risk score.

RESULTS

Of 15,217 patients included, 7583 were outpatients (7.5% confirmed PE) and 7634 were inpatients (60.6% confirmed PE). In all, 10.9% of patients with confirmed PE were outpatients, but outpatient management of confirmed PE was more likely in the latter study period (OR 1.73, 95%CI 1.44-2.09). Among outpatients with confirmed PE, mortality (RR 0.84, 95%CI 0.15-4.61) and readmission (RR 1.25, 95%CI 0.45-3.48) rates were stable, and only 3 major bleeding events were noted. Inpatients with confirmed PE had stable mortality rates (RR 0.95, 95%CI 0.72-1.24).

CONCLUSION

Outpatient PE management increased over 10years while remaining fairly uncommon. Nevertheless, stable mortality and readmission rates indicate this practice is safe in routine care, and add to the growing evidence in support of outpatient PE management.