Accuracy of three-point compression ultrasound for the diagnosis of proximal deep-vein thrombosis in emergency department

Ultrasound Performed by Emergency Physicians for Deep Vein Thrombosis: A Systematic Review

Introduction

Point-of-care ultrasound (POCUS) performed by emergency physicians (EP) has emerged as an effective alternative to radiology department ultrasounds for the diagnosis of lower extremity deep vein thrombosis (DVT). Systematic reviews suggested good sensitivity and specificity overall for EP-performed POCUS for DVT diagnosis, yet high levels of heterogeneity were reported.

Methods

In this systematic review and meta-analysis, we aimed to provide the most up-to-date estimates of the accuracy of EP-performed POCUS for diagnosis of DVT and to explore potential correlations with test performance. We performed systematic searches in MEDLINE and Embase for original, primary data articles from January 2012-June 2021 comparing the efficacy of POCUS performed by EPs to the local standard. Quality Assessment of Diagnostic Accuracy Studies-2 for individual articles are reported. We obtained summary measures of sensitivity, specificity, and their corresponding 95% confidence intervals (CI) using bivariate mixed-effects regression models. We performed meta-regression, subgroup, and sensitivity analyses as planned in the protocol CRD42021268799 submitted to PROSPERO.

Results

Fifteen publications fit the inclusion criteria, totaling 2,511 examinations. Pooled sensitivity and specificity were 90% (95% CI 82%-95%) and 95% (CI 91%-97%), respectively. Subgroup analyses by EP experience found significantly better accuracy for exams performed by EP specialists (93%, CI 88%-97%) vs trainees (77%, CI 60%-94%). Specificity for EP specialists (97%, CI 94%-99%) was higher than for trainees (87%, CI 76%-99%, P = 0.01). Three-point compression ultrasound (CUS) was more sensitive than two-point CUS but was only statistically significant when limited to EP specialists (92% vs 88%, P = 0.07, and 95% vs 88%, P = 0.02, respectively).

Conclusion

Point-of-care ultrasound performed by emergency physicians is sensitive and specific for the diagnosis of suspected DVT when performed by trained attending EPs. Three-point compression ultrasound examination may be more sensitive than two-point CUS.

Utilization of Point-of-Care Ultrasound as an Imaging Modality in the Emergency Department: A Systematic Review and Meta-Analysis

Point-of-care ultrasound (POCUS) is an imaging modality that has become a fundamental part of clinical care provided in the emergency department (ED). The applications of this tool in the ED have ranged from resuscitation, diagnosis, and therapeutic to procedure guidance. This review aims to summarize the evidence on the use of POCUS for diagnosis and procedure guidance. To achieve this, CrossRef, PubMed, Cochrane Library, Web of Science, and Google Scholar databases were extensively searched for studies published between January 2000 and November 2023. Additionally, the risk of bias assessment was performed using the Quality Assessment of Diagnostic Accuracy Studies 2 (for studies on the diagnostic role of POCUS) and Cochrane Risk of Bias tool (for studies on the use of POCUS for procedure guidance). Furthermore, diagnostic accuracy outcomes were pooled using STATA 16 software (StatCorp., College Station, TX, USA), while outcomes related to procedure guidance were pooled using the Review Manager software. The study included 81 articles (74 evaluating the diagnostic application of POCUS and seven evaluating the use of POCUS in guiding clinical procedures). In our findings sensitivities and specificities for various conditions were as follows: appendicitis, 65% and 89%; hydronephrosis, 82% and 74%; small bowel obstruction, 93% and 82%; cholecystitis, 75% and 96%; retinal detachment, 94% and 91%; abscess, 95% and 85%; foreign bodies, 67% and 97%; clavicle fractures, 93% and 94%; distal forearm fractures, 97% and 94%; metacarpal fractures, 94% and 92%; skull fractures, 91% and 97%; and pleural effusion, 91% and 97%. A subgroup analysis of data from 11 studies also showed that the two-point POCUS has a sensitivity and specificity of 89% and 96%, while the three-point POCUS is 87% sensitive and 92% specific in the diagnosis of deep vein thrombosis. In addition, the analyses showed that ultrasound guidance significantly increases the overall success rate of peripheral venous access (p = 0.02) and significantly reduces the number of skin punctures (p = 0.01) compared to conventional methods. In conclusion, POCUS can be used in the ED to diagnose a wide range of clinical conditions accurately. Furthermore, it can be used to guide peripheral venous access and central venous catheter insertion.

EFSUMB Clinical Practice Guidelines for Point-of-Care Ultrasound: Part One (Common Heart and Pulmonary Applications) LONG VERSION

AIMS

 To evaluate the evidence and produce a summary and recommendations for the most common heart and lung applications of point-of-care ultrasound (PoCUS).

METHODS

 We reviewed 10 clinical domains/questions related to common heart and lung applications of PoCUS. Following review of the evidence, a summary and recommendation were produced, including assignment of levels of evidence (LoE) and grading of the recommendation, assessment, development, and evaluation (GRADE). 38 international experts, the expert review group (ERG), were invited to review the evidence presented for each question. A level of agreement of over 75 % was required to progress to the next section. The ERG then reviewed and indicated their level of agreement regarding the summary and recommendation for each question (using a 5-point Likert scale), which was approved if a level of agreement of greater than 75 % was reached. A level of agreement was defined as a summary of "strongly agree" and "agree" on the Likert scale responses.

FINDINGS AND RECOMMENDATIONS

 One question achieved a strong consensus for an assigned LoE of 3 and a weak GRADE recommendation (question 1). The remaining 9 questions achieved broad agreement with one assigned an LoE of 4 and weak GRADE recommendation (question 2), three achieving an LoE of 3 with a weak GRADE recommendation (questions 3-5), three achieved an LoE of 3 with a strong GRADE recommendation (questions 6-8), and the remaining two were assigned an LoE of 2 with a strong GRADE recommendation (questions 9 and 10).

CONCLUSION

 These consensus-derived recommendations should aid clinical practice and highlight areas of further research for PoCUS in acute settings.

Distribution of Lower Extremity Deep Vein Thrombosis and Implications for Limited Compression Ultrasound Examinations

BACKGROUND

Limited compression bedside ultrasonography (LCUS) including two-point, three-point, and extended compression examinations have become increasingly popular among emergency physicians to assess for lower extremity deep venous thrombosis (DVT).

OBJECTIVE

Our objective in this study was to determine the prevalence and distribution of lower extremity DVT in sites identified by complete duplex ultrasonography (CDUS) that may potentially be missed using limited compression ultrasonography techniques.

METHODS

This was a retrospective, multicenter study conducted at 12 hospitals within the Northwell Health system over a span of 4 years. Study participants (emergency department patients) underwent CDUS to assess for possible DVT. Images were reviewed and interpreted by radiologists and vascular surgeons at each of the participating institutions.

RESULTS

A total of 42,487 CDUS examinations were performed, of which 3383 were positive for DVT. DVTs were deemed to be acute in 2664 (79%) and chronic in the remaining 21% on the basis of comparison with previous studies and appearance of the vein. Of the acute DVTs, 136 (5.1%) were confined to the common femoral vein, 116 (4.4%) to the femoral vein, 8 (0.3%) to deep femoral vein, 213 (8.0%) to popliteal vein, and 934 (35.1) to calf veins alone.

CONCLUSIONS

In our study, a significant number of DVTs were identified in sites that may have been potentially missed on LCUS examinations, thereby supporting the use of complete duplex ultrasonography when available.

Non-invasive diagnosis of deep vein thrombosis from ultrasound imaging with machine learning

Deep vein thrombosis (DVT) is a blood clot most commonly found in the leg, which can lead to fatal pulmonary embolism (PE). Compression ultrasound of the legs is the diagnostic gold standard, leading to a definitive diagnosis. However, many patients with possible symptoms are not found to have a DVT, resulting in long referral waiting times for patients and a large clinical burden for specialists. Thus, diagnosis at the point of care by non-specialists is desired. We collect images in a pre-clinical study and investigate a deep learning approach for the automatic interpretation of compression ultrasound images. Our method provides guidance for free-hand ultrasound and aids non-specialists in detecting DVT. We train a deep learning algorithm on ultrasound videos from 255 volunteers and evaluate on a sample size of 53 prospectively enrolled patients from an NHS DVT diagnostic clinic and 30 prospectively enrolled patients from a German DVT clinic. Algorithmic DVT diagnosis performance results in a sensitivity within a 95% CI range of (0.82, 0.94), specificity of (0.70, 0.82), a positive predictive value of (0.65, 0.89), and a negative predictive value of (0.99, 1.00) when compared to the clinical gold standard. To assess the potential benefits of this technology in healthcare we evaluate the entire clinical DVT decision algorithm and provide cost analysis when integrating our approach into diagnostic pathways for DVT. Our approach is estimated to generate a positive net monetary benefit at costs up to £72 to £175 per software-supported examination, assuming a willingness to pay of £20,000/QALY.

Where There's Smoke, There's Fire: A Case Report of Turbulent Blood Flow in Lower Extremity Point-of-care Ultrasound in COVID-19

INTRODUCTION

Coronavirus disease 2019 (COVID-19) may predispose patients to increased risk of venous thromboembolism (VTE) due to various pathophysiological mechanisms, including but not limited to endothelial injury, inflammation, cytokine-mediated microvascular damage, and reactive thrombocytosis. A high risk of vessel thrombosis correlates with disease severity, making early identification and treatment of prime consideration.Although identification of a deep venous thrombosis (DVT) or pulmonary embolism warrants immediate treatment with anticoagulation, trying to predict which COVID-19 patients may be at increased risk for developing these pathologies is challenging.

CASE REPORTS

We present two cases of patients with COVID-19 who had ultrasonographic findings of turbulent blood flow within the deep venous system, without clear evidence of acute proximal DVT, who were subsequently found to have significant VTE.

CONCLUSION

Point-of-care lower extremity ultrasound has become one of the core applications used by emergency physicians. Typically we perform compression ultrasound for DVT evaluation. This novel finding of turbulent blood flow, or "smoke," within the deep venous system, may serve as a marker of increased risk of clot development and could be an indication to consider early anticoagulation.

Prevalence and predictors of alternative diagnoses on whole-leg ultrasound negative for acute deep venous thrombosis

Background

To investigate the prevalence, spectrum, and predictors of alternative diagnoses explaining leg symptoms in patients negative for suspected acute deep venous thrombosis (DVT), which can be detected with whole-leg ultrasound.

Methods

We retrospectively analyzed a cohort of 789 patients (median age 70 years, 50.6% women) evaluated with a whole-leg ultrasound examination for suspected acute DVT within one year. All findings in the radiology report were analyzed and electronic chart review was performed to collect clinical information.

Results

Ultrasound was negative for acute DVT in 531 patients (67.3%). Among these, alternative diagnoses explaining leg symptoms were seen in 349 patients (65.7%). The most frequent alternative diagnoses were chronic venous insufficiency (147 patients, 27.7%), followed by lymphedema (48 patients, 9.0%) and chronic post-thrombotic changes (41 patients, 7.7%). Patients with alternative diagnoses were older (median 71 vs. 66 years, p = 0.0226), as well as more likely to present with leg swelling (39.5% vs. 23.1%, p = 0.0002), difference in leg circumference (25.5% vs. 14.8%, p = 0.0055) and redness (7.7% vs. 2.7%, p = 0.0213) than patients without alternative diagnosis. Independent predictors of finding alternative diagnoses on whole-leg ultrasound were older age (odds ratio 1.014 per year, p = 0.0119), leg swelling (OR 1.949, p = 0.0020) and history of previous DVT (OR 2.235, p = 0.0154).

Conclusions

Alternative diagnoses explaining leg symptoms can be detected on whole-leg ultrasound in two thirds of patients with no evidence of acute DVT. Our data supports performing a comprehensive ultrasound evaluation beyond the venous system, particularly, in older patients, who present with leg swelling and a past history of DVT.

Assessment of the Need for Early Initiation of Rehabilitation Treatments in Patients with Coronavirus Disease 2019

Objective

The aim of this study was to describe the clinical characteristics of coronavirus disease (COVID-19) patients, including risk factors for deep vein thrombosis and pulmonary embolism, and to evaluate the need for rehabilitation to prevent pulmonary embolism.

Methods

A retrospective medical record review was conducted of patients admitted to the study hospital with COVID-19 between April 2 and April 23, 2020. The clinical characteristics and blood test results of patients with no history on admission of oral anticoagulant use were evaluated to assess the importance of inflammation and clotting function as risk factors for pulmonary embolism.

Results

A total of 51 patients with COVID-19 were admitted during the study period. Their median age was 54.0 years (range: 41-63 years) and 38 of 51 (74.5%) were men. The most common comorbidities in men were diabetes (9/38, 23.7%) and hypertension (13/38, 34.2%). On admission, white blood cell counts were normal in both sexes, whereas C-reactive protein and hemostatic marker levels, except for the activated partial thromboplastin time, were significantly higher in men. Moreover, C-reactive protein and hemostatic marker levels were significantly higher in patients that required invasive ventilation. Two patients were diagnosed with acute pulmonary embolism, neither of whom required invasive ventilation.

Conclusions

Hypercoagulability and hyperinflammation were observed in COVID-19 patients, especially in men with high oxygen demand. We recommend anticoagulant therapy and early rehabilitation intervention to prevent pulmonary embolism in COVID-19 patients.