Importance of risk factors for the evaluation of patients with a suspected pulmonary embolism

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.

DVT and Pulmonary Embolism Following Knee Arthroscopy: The Role of Genetic Predisposition and Autoimmune Antibodies: A Report of 3 Cases

Deep vein thrombosis (DVT) after arthroscopy has been considered a rare event; however, recent studies using ultrasound and venography have shown that the incidence of DVTs is underestimated. CASES:: This report describes 3 patients with DVT and/or PE after knee arthroscopy who were attributed to a genetic predisposition of hypercoagulability unknown to the patient and surgeon. CONCLUSIONS:: Genetic predisposition and autoimmune antibodies may play a role in the development of DVT after knee arthroscopy. We recommend focused questions regarding family history be added to the standard DVT/PE preoperative questionnaire.

Unenhanced multidetector computed tomography findings in acute central pulmonary embolism

Background

Computed tomography pulmonary angiography (CTPA) is the gold standard for the diagnosis of pulmonary embolism (PE). However, contrast is contraindicated in some patients. The purpose of this study was to determine the diagnostic accuracy of unenhanced multidetector CT (MDCT) for diagnosis of central PE using CTPA as the gold standard.

Methods

The records of patients with suspected PE seen between 2010 and 2013 were retrospectively reviewed. Inclusion criteria were an acute, central PE confirmed by CTPA and non-enhanced MDCT before contrast injection. Patients with a PE ruled out by CTPA served as a control group. MDCT findings studied were high-attenuation emboli in pulmonary artery (PA), main PA dilatation > 33.2 mm, and peripheral wedge-shaped consolidation. Receiver operating characteristic (ROC) analysis was used to determine the sensitivity and specificity of unenhanced MDCT to detect PE. Wells score of all patients were calculated using data extracted from medical records prior to imaging analysis.

Results

Thirty-two patients with a PE confirmed by CTPA and 32 with a PE ruled out by CTPA were included. Among the three main MDCT findings, high-attenuation emboli in the PA showed best diagnostic performance (Sensitivity 72.9%; Specificity 100%), followed by main PA dilatation > 33.2 mm (sensitivity 46.9%; specificity 90.6%), and peripheral wedge-shaped consolidation (sensitivity 43.8%; specificity 78.1%). Given any one or more positive findings on unenhanced MDCT, the sensitivity was 96.9% and specificity was 71.9% for a diagnosis of PE in patients. The area under the curve (AUC) of a composite measure of unenhanced MDCT findings (0.909) was significantly higher than that of the Wells score (0.688), indicating unenhanced MDCT was reliable for detecting PE than Wells score.

Conclusions

Unenhanced MDCT is an alternative for the diagnosis of acute central PE when CTPA is not available.

Missed Massive Pulmonary Embolism and the Hidden Threat of a Distal Deep Vein Thrombosis

A 47-year-old woman presented to her GP (general practitioner) surgery with a left leg pain of 4 days duration after a recent 4-hour flight. She was taking the oral combined contraceptive pill and had no past medical history. She had a low predictive Wells score for deep vein thrombosis, but her D-dimer was positive, so she had a proximal lower limb vein ultrasound scan as per the National Institute for Clinical Excellence guidelines, which was negative. Two days later, she presented to the emergency department with a collapse and dyspnea. Her blood pressure was unrecordable in the ambulance, and she was severely peripherally cyanosed with a blood pressure of 64/40 mm Hg in the emergency department. She had a computed tomography pulmonary angiogram, which confirmed extensive bilateral pulmonary emboli with right ventricular strain. She had 2 cardiac arrests while in hospital and is now on long-term anticoagulation.

Risk Stratification Model: Lower-Extremity Ultrasonography for Hospitalized Patients with Suspected Deep Vein Thrombosis

BACKGROUND

The Wells score for deep venous thrombosis (DVT) has a high failure rate and low efficiency among inpatients.

OBJECTIVE

To create and validate an inpatient-specific risk stratification model to help assess pre-test probability of DVT in hospitalized patients.

DESIGN

Prospective cohort study of hospitalized patients undergoing lower-extremity ultrasonography studies (LEUS) for suspected DVT. Demographics, physical findings, medical history, medications, hospitalization, and laboratory and imaging results were collected. Samples were divided into model derivation (patients undergoing LEUS 11/1/2012-12/31/2013) and validation cohorts (LEUS 1/1/2014-5/31/2015). A DVT prediction rule was derived using the recursive partitioning algorithm (decision tree-type approach) and was then validated.

PARTICIPANTS

Adult inpatients undergoing LEUS for suspected DVT from November 2012 to May 2015, excluding those with DVT in the prior 3 months, at a 793-bed, urban academic quaternary-care hospital with ~50,000 admissions annually.

MAIN MEASURES

The primary outcome was the presence of proximal DVT, and the secondary outcome was the presence of any DVT (proximal or distal). Model sensitivity and specificity for predicting DVT were calculated.

KEY RESULTS

Recursive partitioning yielded four variables (previous DVT, active cancer, hospitalization ≥ 6 days, age ≥ 46 years) that optimized the prediction of proximal DVT and yield in the derivation cohort. From this decision tree, we stratified a scoring system using the validation cohort, categorizing patients into low- and high-risk groups. The incidence rates of proximal DVT were 2.9% and 12.0%, and of any DVT were 5.2% and 21.0%, for the low- and high-risk groups, respectively. The AUC for the discriminatory accuracy of the Center for Evidence-Based Imaging (CEBI) score for risk of proximal DVT identified on LEUS was 0.73. Model sensitivity was 98.1% for proximal and 98.1% for any DVT.

CONCLUSIONS

In hospitalized adults, specific factors can help clinicians predict risk of DVT, identifying those with low pre-test probability, in whom ultrasonography can be safely avoided.