Diagnosis Of Pulmonary Embolism Research Articles

A Comparison of the Diagnostic Value of Multiorgan Point-of-care Ultrasound between High-risk and Medium-to-low-risk Pulmonary Embolism Cases.

This study aimed to explore the diagnostic value of multiorgan (heart, lungs, blood vessels) point-of-care ultrasound (PoCUS) in patients with high-risk and medium-to-low-risk pulmonary embolism (PE). Clinical data of 92 patients with suspected PE, admitted to Hangzhou TCM Hospital affiliated with Zhejiang Chinese Medical University from July 2021 to June 2023, were retrospectively analyzed. According to hemodynamic status, patients were divided into the high-risk (n=28) and the medium-to-low-risk groups (n=64). Using computed tomography (CT) and pulmonary angiography (CTPA) as the gold standard, all patients underwent multiorgan PoCUS examination. The sensitivity, specificity, and accuracy of different methods for diagnosing PE, as well as the time difference between multiorgan PoCUS examination and CTPA, were compared. Differences in measurement values of relevant indicators in all groups were analyzed. In the high-risk group of patients, CTPA identified 15 cases of PE. In contrast, the PoCUS examination confirmed PE diagnosis in 14 cases (true positive), while 10 cases were diagnosed as true negative, one case as false negative, and three cases as false positive. In the medium-to-low-risk group, CTPA identified 50 patients with PE, while multiorgan PoCUS confirmed PE diagnosis in 33 cases (true positive), and identified 9 true negative, 17 false negative, and 5 false positive PE cases. Kappa test of the consistency between the results of multiorgan PoCUS and CTPA showed that multiorgan PoCUS had higher sensitivity, negative predictive value, and accuracy in the high-risk group compared to the medium-tolow- risk group (p<0.05). Cohen's Kappa value of the high-risk group was 0.710, indicating moderate consistency between PoCUS and CTPA results, while Cohen's Kappa value of 0.231 for the medium and low-risk group indicated poor consistency. There was a significant difference in ultrasound parameters between the high-risk and the medium-to-low-risk group (p<0.05). The time required for multiorgan PoCUS in both groups was significantly shorter than that for the CTPA. There was no significant difference in the time required for PoCUS between the two groups (p>0.05). Multiorgan PoCUS has been found to have higher sensitivity and accuracy in diagnosing patients with high-risk PE compared to those with medium-to-low-risk PE, and a shorter imaging time compared to CTPA.

Diagnosis and treatment of pulmonary embolism. Recommendations of the Thromboembolic Disease Group of the Spanish Society of Internal Medicine 2024.

Pulmonary embolism (PE) is a disease with a rising incidence rate. This article presents the recommendations for the diagnosis and treatment of PE of the Thromboembolic Disease Group of the Spanish Society of Internal Medicine (SEMI). The main objective is to facilitate decision making to improve the diagnostic and therapeutic approach based on published evidence. The final justification of the document is to improve the comprehensive care of the patient with PE.

Dynamics of troponins and 30-day mortality in hospitalized patients with pulmonary embolism.

In patients with pulmonary embolism (PE), the impact of repeated troponin I or T (TnI/TnT) measurements remains unclear. Using Danish national registries, we identified PE patients (≥18years) hospitalized between 2013 and 2018 with initial TnI or TnT measurement within -1/+1day from admission and >1 repeated measurement within three days. Trajectories of TnI and TnT were identified using latent class trajectory modeling. Hazard ratios for 30-day mortality were compared across trajectories via multivariable Cox regression. Among 1539 patients with TnI measurements and 1323 with TnT measurements, three distinct trajectories were identified. Trajectory I (nTnI=286, nTnT=472) exhibited consistently low TnI/TnT concentrations, trajectory II (nTnI=1076, nTnT=724) demonstrated initial elevated TnI/TnT decreasing within 24h, and trajectory III (nTnI=177, nTnT=127) was characterized by elevated index TnI/TnT increasing within 10h. 30-day mortality rates were higher in trajectory II and III compared to I in both the TnI (3%, 7% and 18% across trajectory I to III) and the TnT (1%, 9% and 20% across trajectory I to III) cohort. After adjustment hazard ratio of 30-day mortality for trajectory II vs. I was 7.42 (95% CI 1.00-54.84, p=0.04, TnI) and 2.93 (95% CI 1.17-7.33, p=0.02 TnT); and for trajectory III vs. I, 16.42 (95% CI 2.42-127.29, p=0.007, TnI) and 8.21 (95% CI 2.78-24.19, p<0.001, TnT). A steep increase in TnI or TnT concentration within 10h of PE diagnosis significantly escalates 30-day mortality risk indicating that early serial sampling may enhance risk stratification of PE patients.

Multiorgan Ultrasound for the Diagnosis of Submassive Pulmonary Embolism in a Critically Ill Patient

Multiorgan Ultrasound for the Diagnosis of Submassive Pulmonary Embolism in a Critically Ill Patient

Prevalence of Pulmonary Embolism in COVID-19 Positive Critically Ill Children.

To investigate the prevalence of pulmonary embolism (PE) in children admitted to critical care diagnosed with COVID-19 infection. Retrospective database study. Data reported to the Virtual Pediatric Systems, 2018-2021. Patients 28 days to younger than 18 years old, admitted to a PICU with either PE or COVID-19 diagnoses. None. Among the PE-positive subgroups, from January 2020 to December 2021, 78 patients (14%) had an acute COVID-19 infection. The prevalence of PE pre-pandemic period (2018-2019) was 0.19% and for pandemic period (2020-2021) was 0.26% (p < 0.001). During the pandemic period, the prevalence of PE for COVID-negative patients was 0.21% and for COVID-positive patients was 1.01% (p < 0.001). The result shows that the chance to develop PE for COVID-positive patients is 4.8 times that for COVID-negative patients during the pandemic. In the subgroup of the PE-positive patients, 55.1% were Black or African American in the COVID-positive group and 19% in the COVID-negative group (p < 0.001). A multivariable logistic regression showed that race was an independent risk factor for COVID in PE-positive patients. Our study demonstrates a significant increase in the prevalence of PE among pediatric patients admitted to PICUs during the COVID-19 pandemic compared with pre-pandemic. Our study indicates that COVID-positive patients are 4.8 times more likely to develop PE than COVID-negative patients. Additionally, the study highlights substantial racial disparities in the prevalence of PE, with Black or African American patients being disproportionately affected.

Acute pulmonary embolism with and without hemodynamic instability (2003-2022): A Swiss nationwide epidemiological study.

Data on the epidemiological burden of acute pulmonary embolism (PE) in Switzerland is unavailable. Knowledge gaps remain on trends in PE-related comorbidities, PE severity, and length of in-hospital stay (LOS) at a nationwide level. We used nationwide, patient-level data including all patients aged 15 years or older hospitalized for PE in Switzerland from 2003 to 2022, amounting to N=180,600. Additionally, we analyzed the Swiss Death Registry for the same period. We estimated the disease-specific age-standardized incidence rates, mortality rates, in-hospital case fatality rates, proportional mortality rates, and LOS. Analyses were stratified by sex and the presence of features of high-risk PE. During the study period, the PE-related incidence rate increased from 0.87 (95%CI: 0.82;0.92) per 1,000 population in 2003 to 1.19 (95%CI: 1.15;1.24) in 2022. In contrast, a decreasing trend was found for mortality rates (18.7 [95%CI: 16.8;20.6] per 100,000 population in 2003, 13 [95%CI: 11.7;14.2] in 2022), in-hospital case fatality rate (9.8 [95%CI: 9.1;10.5] deaths per 100 hospitalized PE patients in 2003, 7.9 [95%CI: 7.4;8.5] in 2019, subsequent increase during COVID-19 pandemic), and LOS (11 [Q1-Q3: 7-18] days in 2003, 8 [Q1-Q3: 4-16] in 2022). No major sex-differences in trends were present. Except for LOS reduction, patients with high-risk features presented with similar trends. The incidence of acute PE in Switzerland increased over the last 20 years. Despite increasing trends in the median age at PE diagnosis, in-hospital case fatality and mortality rate decreased, particularly among patients with high-risk features, and the LOS progressively declined.

Acute management of massive pulmonary embolism in pregnancy.

•Massive pulmonary embolism (PE) during pregnancy or the postpartum period is a rare but potentially lethal event.•Physiological changes in the coagulation system during pregnancy and puerperium would lead to a hypercoagulable state.•Diagnosis of PE in pregnancy remains a challenge due to physiological changes in pregnancy. There are no validated scoring systems for assessing pregnant/postpartum women with suspected PE. Massive PE should be suspected in all cases with haemodynamic instability in pregnancy.•The Management of massive pulmonary embolism should be timely and aggressive. Thrombolysis for massive PE during pregnancy and the postpartum period has shown to be associated with high maternal and fetal survival (94% and 88%). But other therapeutic options such as (catheter [or surgical] thrombectomy, ECMO) should be considered in the postpartum period, given the high risk of major bleeding with thrombolysis.•Thrombolysis remains the most-used and reasonably successful modality of treatment in pregnancy but should be avoided in the postpartum period as it can cause life-threatening haemorrhage. During the post-partum period, thrombectomy is the treatment of choice. •To understand the pathophysiology of massive PE.•To appreciate the treatment options in pregnancy and postpartum period and their pros and cons.•To understand the need for further work in this area especially in creating a validated algorithm for diagnosing PE in pregnancy and postpartum period.

Central Catheter Complicated with Fatal Pulmonary Embolism in a Patient under Chronic Hemodialysis: A Case Report

Introduction: The use of central venous catheter is a common practice in hemodialysis in Mali. Its use exposes to risks such as infection, stenosis, thrombosis among others. Pulmonary embolism is a rare but serious complication. The aim of our work was to offer advice on the diagnosis, risk factors, treatment and prevention of deep vein thrombosis following the placement of a central catheter. Observation: This was a 56-year-old woman, a housewife living in the city of Bamako. She had been on chronic hemodialysis for 6 months due to nephroangiosclerosis, at a rate of two four-hour sessions per week through a right femoral catheter. Before her hospitalization, she had a fever, physical asthenia, anorexia, a feeling of heavy leg on the right and abdominal pain. The clinical examination found a conscious patient, with little color and normal parameters, a swelling of the right leg with pain and redness. The biological assessment revealed hypochromic microcytic anemia, Procalcitonin at 2.75ng/l. The Doppler of the right lower limb confirmed deep vein thrombosis. The pulsed cardiac Doppler and the ECG confirmed the diagnosis of pulmonary embolism. Curative treatment of venous thrombosis was started. The immediate aftermath was marked by respiratory problems requiring oxygen therapy, acute circulatory failure syndrome with coldness of the extremities. The outcome was unfavorable with the death of the patient. Conclusion: The use of central venous catheter for hemodialysis as first-line treatment remains frequent in Mali. Patients should benefit from increased monitoring and prophylactic treatment to prevent the occurrence of thromboembolic events.

Assessment of the fragmented QRS relative frequency and its predictive value in patients with pulmonary embolism.

Acute pulmonary embolism can quickly cause hemodynamic collapse and death. Recent studies have shown that different characteristics of electrocardiogram (ECG) can be used to predict the prognosis of patients. This study aimed to investigate the relative frequency of fragmented QRS in the ECG of patients with pulmonary embolism and its prognostic value. This study was conducted retrospectively. The files of 106 patients hospitalized with a diagnosis of pulmonary embolism from January 2016 to the end of March 2020 were selected and reviewed. The findings of the ECG, including the ST elevation in V1-V4 leads with and without T invention, right axis deviation, right bundle branch block (RBBB), PR, QRS, QTc intervals, type of treatment (thrombolysis or embolectomy), cardiogenic shock, mortality were collected. Finally, the data were recorded and analyzed in SPSS software Version 16. Hypertension, dyslipidemia, and diabetes mellitus were the most frequent risk factors among the patients. The relative frequency of fragmented QRS, at least in one lead, was 26.2%. The use of thrombolysis, mechanical ventilation, embolectomy, cardiogenic shock, and in-hospital death was significantly higher among patients who had fragmented QRS (P<0.001). CTNI was significantly higher in patients with fragmented QRS (P=0.001). In patients with fragmented QRS large vessels, involvement was significantly higher. This study showed that the presence of fragmented QRS in the ECG of acute embolism patients has a significant relationship with cardiogenic shock, hospital mortality, and the need for advanced treatment methods such as intubation, embolectomy, and the use of thrombolysis.

Pulmonary Embolism in the Elderly: From Symptoms to Speckle Tracking Echocardiography.

(1) Background: There are little data about the differences in clinical and echocardiographic characteristics between elderly (aged ≥ 65 years) and younger patients with acute pulmonary embolism (PE). (2) Methods: Consecutive patients diagnosed with PE in a tertiary hospital were identified. Clinical characteristics, biomarkers and transthoracic echocardiography indices including right ventricular free wall longitudinal strain (RV-FWLS) were recorded. (3) Results: Of 200 patients enrolled, 19 patients had high-risk PE and were excluded from the study. Compared to younger patients, elderly patients with PE had less frequently pain and typical symptoms and more often were hospitalized due to another reason before the PE diagnosis. The elderly had higher values of D-dimer, high-sensitivity troponin I and brain natriuretic peptide (BNP). Echocardiographic differences were noted and the elderly had lower values of pulmonary vascular acceleration time, RV E/A ratio and lower tricuspid annular plane systolic excursion/pulmonary artery systolic pressure ratio. The RV-FWLS index did not show a statistically significant difference in distribution between age groups ≥ 65 and <65 years old. The RV diameter was similar across all age groups. (4) Conclusions: The elderly have differences compared with younger patients with PE regarding the mode of presentation, the values of biomarkers like D-dimer, BNP and troponins and some echocardiographic indices of RV affection.

Diagnostic Value of the Alveolar-Arterial Oxygen Gradient in Pulmonary Embolism: A Cross-Sectional Study.

Background/Objectives: Pulmonary embolism (PE) is a potentially serious condition characterized by the blockage of blood vessels in the lungs, often presenting significant diagnostic challenges due to its non-specific symptoms. This study aimed to evaluate the utility of the alveolar-arterial (A-a) oxygen gradient as a diagnostic tool for PE, hypothesizing that it could enhance early detection when combined with other clinical markers. Methods: We retrospectively analyzed 168 patients at the University Hospital Center Split. This study correlated A-a gradients with PE confirmed by CT pulmonary angiography. Key clinical and biochemical markers, including heart rate, C-reactive protein (CRP), pro-brain natriuretic peptide (NT-proBNP), D-dimer, high-sensitivity troponin (hs-troponin), and arterial oxygen pressure (PaO2), were assessed. Results: Our findings revealed that patients with PE had significantly higher A-a gradients than those without PE. The observed-to-expected ratio for the A-a gradient was notably increased in the PE group. Additionally, patients with PE exhibited elevated heart rate, CRP, NT-proBNP, D-dimer, and hs-troponin levels, while PaO2 levels were notably lower. Conclusions: This study demonstrates that an elevated A-a gradient reflects the severity of gas exchange impairment in PE. The results suggest that early diagnosis of PE may be improved by incorporating A-a gradient analysis alongside other clinical markers, potentially leading to more effective and timely interventions.

VA-ECOM assisted percutaneous mechanical thrombectomy treatment high-risk pulmonary embolism.

Percutaneous mechanical thrombectomy (PMT) is increasingly used in the treatment of intermediate and high-risk acute pulmonary embolism (PE), and the treatment of high-risk PE with the aid of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has also been reported. However, there are few reports of VA-ECOM-assisted PMT in the treatment of high-risk PE. The purpose of this study is to summarize the data of 11 patients with high-risk PE treated with VA-ECMO assisted PMT, and propose feasible treatment methods for such patients. This multicenter retrospective study included patients with acute high-risk PE who were treated with VA-ECMO-assisted PMT from January 2021 to June 2024. The analysis focused on the right/left ventricle ratio, biomarkers, and pulmonary artery pressure before and after the VA-ECMO-assisted PMT treatment. All 11 high-risk PE patients suffered cardiac arrest before treatment, computered tomograhy pulmonary angiography (CTPA) confirmed the diagnosis of PE, and all patients received VA-ECMO-assisted PMT therapy. The median age of the 11 patients was 54 years (range 18-72), the median duration of ECMO was 4.48 days (range 1.04-18.02), and the mean hospitalization time was 21 days (range 14-112). All patients received percutaneous thrombectomy, achieving a 100% technical success rate. The mortality rate was 27.3% during the 90-day follow-up. The 12-month mortality rate was 36.4%. VA-ECMO-assisted PMT technology can rapidly improve pulmonary hemodynamics while maintaining stable blood flow, thereby reducing in-hospital mortality in high-risk patients with pulmonary embolism complicated by cardiac arrest.

Current Role of CT Pulmonary Angiography in Pulmonary Embolism: A State-of-the-Art Review.

The purpose of this study is to conduct a literature review on the current role of computed tomography pulmonary angiography (CTPA) in the diagnosis and prognosis of pulmonary embolism (PE). It addresses key topics such as the quantification of the thrombotic burden, its role as a predictor of mortality, new diagnostic techniques that are available, the possibility of analyzing the thrombus composition to differentiate its evolutionary stage, and the applicability of artificial intelligence (AI) in PE through CTPA. The only finding from CTPA that has been validated as a prognostic factor so far is the right ventricle/left ventricle (RV/LV) diameter ratio being >1, which is associated with a 2.5-fold higher risk of all-cause mortality or adverse events, and a 5-fold higher risk of PE-related mortality. The increasing use of techniques such as dual-energy computed tomography allows for the more accurate diagnosis of perfusion defects, which may go undetected in conventional computed tomography, identifying up to 92% of these defects compared to 78% being detected by CTPA. Additionally, it is essential to explore the latest advances in the application of AI to CTPA, which are currently expanding and have demonstrated a 23% improvement in the detection of subsegmental emboli compared to manual interpretation. With deep image analysis, up to a 95% accuracy has been achieved in predicting PE severity based on the thrombus volume and perfusion deficits. These advancements over the past 10 years significantly contribute to early intervention strategies and, therefore, to the improvement of morbidity and mortality outcomes for these patients.

The Effectiveness of Systemic Thrombolysis in the Treatment of Massive Pulmonary Embolism

The article presents a case of timely diagnosis and successful treatment of massive pulmonary embolism in a young man suffering from obesity, hypertension and osteochondrosis of the lumbar spine. The disease was manifested with symptoms of acute respiratory failure, hemodynamics was stable. Laboratory tests revealed an increase in the level of D-dimer and hypercoagulation. Electrocardiographic examination revealed signs of overloading of the right ventricle, and echocardiography revealed pulmonary hypertension of the 2nd degree. Ultrasound examination of the venous system of the lower extremities detected that the cause of the embolism was the migration of a blood clot from a thrombosed femoral vein. The diagnosis was confirmed during computed tomography of the lungs with intravenous contrast. Thrombolytic therapy was performed with alteplase in standard dosages. The patient underwent anticoagulant therapy for 3 months.

Management and Outcomes of Pulmonary Embolism in Women of Reproductive Age Admitted to Urban Versus Rural Areas Compared to Men.

There are limited and conflicting data on sex and urban-rural disparities in outcomes of patients with pulmonary embolism (PE) in the reproductive age group. Our object was to assess sex disparities in the reproductive age group cohort. All adult non-elective admissions in the reproductive age group (18-49 years) with a primary diagnosis of PE and with no missing sex/age data were identified using the National Inpatient Sample. Females and males were stratified into rural and urban location based on hospital information. Outcomes of interest included in-hospital mortality, complication rates, variations in management, total hospitalization costs, and length of stay. During 01/01/2016 to 12/31/2020, 180,898 PE admissions aged 18-49 years were identified (rural-12,319 [6.8%]). Females comprised 54.8% and 55.1% of the rural and urban cohorts, respectively. Overall, compared to males, females in urban and rural regions had largely comparable rates of definitive PE interventions, except lower rates of catheter directed therapy (4.7 vs. 3.6%, p < 0.001) in females admitted to urban hospitals. Despite younger age, higher comorbidity, and lower utilization of PE interventions, females in both regions had similar unadjusted in-hospital mortality (rural 1.1% vs. 1.0%; p = 0.93 and urban 1.8% vs. 1.7%; p = 0.78) and hospitalization costs compared to males. In conclusion, females of reproductive age group had comparable in-hospital outcomes to males in both urban and rural areas. Females in urban areas had lower utilization of advanced PE interventions, potentially indicating selective management strategies in different settings.

Current strategies for the diagnosis of pulmonary embolism

Current strategies for the diagnosis of pulmonary embolism

Evaluation of a Computer-Based Morphological Analysis Method for Free-Text Responses in the General Medicine In-Training Examination: Algorithm Validation Study.

The General Medicine In-Training Examination (GM-ITE) tests clinical knowledge in a 2-year postgraduate residency program in Japan. In the academic year 2021, as a domain of medical safety, the GM-ITE included questions regarding the diagnosis from medical history and physical findings through video viewing and the skills in presenting a case. Examinees watched a video or audio recording of a patient examination and provided free-text responses. However, the human cost of scoring free-text answers may limit the implementation of GM-ITE. A simple morphological analysis and word-matching model, thus, can be used to score free-text responses. This study aimed to compare human versus computer scoring of free-text responses and qualitatively evaluate the discrepancies between human- and machine-generated scores to assess the efficacy of machine scoring. After obtaining consent for participation in the study, the authors used text data from residents who voluntarily answered the GM-ITE patient reproduction video-based questions involving simulated patients. The GM-ITE used video-based questions to simulate a patient's consultation in the emergency room with a diagnosis of pulmonary embolism following a fracture. Residents provided statements for the case presentation. We obtained human-generated scores by collating the results of 2 independent scorers and machine-generated scores by converting the free-text responses into a word sequence through segmentation and morphological analysis and matching them with a prepared list of correct answers in 2022. Of the 104 responses collected-63 for postgraduate year 1 and 41 for postgraduate year 2-39 cases remained for final analysis after excluding invalid responses. The authors found discrepancies between human and machine scoring in 14 questions (7.2%); some were due to shortcomings in machine scoring that could be resolved by maintaining a list of correct words and dictionaries, whereas others were due to human error. Machine scoring is comparable to human scoring. It requires a simple program and calibration but can potentially reduce the cost of scoring free-text responses.

Pulmonary embolism diagnosis with D-dimer levels and computed tomography

Pulmonary embolism diagnosis with D-dimer levels and computed tomography

Sex Differences in Testing for Pulmonary Embolism Among Emergency Department Patients Aged 18–49 by Chief Complaint

BackgroundWomen undergo diagnostic testing for pulmonary embolism (PE) in greater numbers than men, despite the disease incidence being higher in men overall. It is unknown if testing for PE varies based on patient chief complaint. MethodsThis retrospective cohort study was conducted at two academic tertiary care hospitals. Nonpregnant adult patients (aged 18–49 years) were included if they presented to the ED between 1/1/2016 and 12/31/2018 with nontraumatic mechanisms and any of the following chief complaints: chest pain, shortness of breath, hemoptysis, or syncope AND had objective testing for PE. Data were obtained from the electronic medical record and analyzed descriptively. Four outcome variables were assessed: receipt of D-dimer testing, D-dimer positivity, receipt of pulmonary vascular imaging, and diagnosis of PE. ResultsWe studied 1,991 unique patient encounters, most of whom (63%; 1,256/1,991) were female. Overall, female patients had higher odds of receiving D-dimer testing than male patients (OR 1.30, CI 1.06–1.59, P = 0.015), while they had lower odds of being diagnosed with PE (OR 0.57, CI 0.36–0.90, P = 0.019). However, this trend varied by chief complaint. Among patients with chest pain, females had higher odds of having a D-dimer performed (OR 1.35, CI 1.01–1.80, P = 0.049) and lower odds of being diagnosed with PE (OR 0.36, CI 0.18–0.70, P = 0.003) than males. ConclusionsBoth patient sex and chief complaint were associated with trends in diagnostic testing for PE. Among patients with chest pain, females are significantly more likely to be tested with a D-dimer and less likely to be diagnosed with PE.

CT Pulmonary Angiogram Clinical Pretest Probability Tool: Impact on Emergency Department Utilization

ObjectiveCurrently, computed tomographic pulmonary angiogram (CTPA) for evaluating acute pulmonary embolism (PE) in Emergency Departments (EDs) is overused and with low yields. The goal of this study is to assess the impact of an evidence-based clinical decision support (CDS) tool, aimed at optimizing appropriate use of CTPA for evaluating PE. MethodsThe study was performed at EDs in a large healthcare system and included 9 academic and community hospitals. The primary outcome was the percent difference in utilization (number of CTPA performed/number of ED visits) and secondary outcome was yield (percentage of CTPA positive for acute PE), comparing 12 months before (6/1/2021-5/31/2022) vs. 12 months after (6/1/2022-5/31/2023) a system-wide implementation of the CDS. Univariate and multivariable analyses using logistic regression were performed to assess factors associated with diagnosis of acute PE. Statistical process control (SPC) charts were used to assess monthly trends in utilization and yield. ResultsAmong 931,677 visits to Emergency Departments, 28,101 CTPAs were performed on 24,675 patients. 14,825 CTPAs were performed among 455,038 visits (3.26%) pre-intervention; 13,276 among 476,639 visits (2.79%) post-intervention, a 14.51% relative decrease in CTPA utilization (chi-square, p<0.001). CTPA yield remained unchanged (1371/14825=9.25% pre- vs. 1184/13276=8.92% post-intervention; chi-square, p=0.34). Patients with COVID diagnosis prior to CTPA had higher probability of acute PE. SPC charts demonstrated seasonal variation in utilization (Friedman test, p=0.047). DiscussionImplementing a CDS based on validated decision rules was associated with a significant reduction in CTPA utilization. The change was immediate and sustained for 12 months post-intervention.