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Three Part Question

In [adult Emergency Department patients with suspected deep venous thrombosis], does [Emergency Physician performed ultrasound] have [similar accuracy to radiology based ultrasonography]?

Clinical Scenario

A 46 year old female presents to the Emergency Department out of hours with left leg swelling. Wells score for DVT is +2. You suspect a lower limb DVT and wonder if you can use point-of-care ultrasound to make your diagnosis.

Search Strategy

Medline Database (National Library of Medicine, Bethesda, MD)
Ovid SP (Ovid, New York, NY)
CINAHL Database
Google Scholar Search

A systematic literature search was performed, using the Medline database (National Library of Medicine, Bethesda, MD), Ovid SP (Ovid, New York, NY) and CINAHL database. Google Scholar web search engine was also searched. MeSH terms and relevant free text terms were used. The following search terms (synonyms and combinations) were used: DVT, EPPU, emergency physician performed ultrasound, hand-held ultrasound, emergencies, emergency medicine, emergency medical services, emergency service, hospital, venous thrombosis, thrombophlebitis, venous thromboembolism, POCUS, point of care ultrasound, bedside ultrasound, diagnostic ultrasonic examination, imaging, method, diagnostic ultrasound, duplex echography, echography, echoscopy, echo sound, high resolution echography, sonogram, sonographic examination, sonographic screening, sonography, ultrasonic detection, diagnosis, echo, examination, scanning, scintillation, ultra-sonogram, ultrasonographic examination, screening, ultrasound diagnosis, ultrasonography.

Search Outcome

The results obtained were then manually scanned for relevant articles by two independent reviewers. Discordances were discussed and a consensus was reached for each article in question. The search was conducted from 2000 to 2021. Studies were included if they were in English, original research publications and contained data on point of care ultrasound in emergency department and thromboembolism. The following data was extracted from the studies examined: patient group, study type, outcomes, results & study weaknesses. We also reviewed the references of the selected studies to include additional relevant studies which were not found in the initial electronic search. Using these methods, a total of 26 studies were included for review.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Blaivas et al 2000 USA	Suspicion of DVT and high-risk Convenience Sampling (when 1 of 5 emergency physicians trained were available)	Prospective observational	Accuracy of trained EM physicians using lower-extremity doppler ultrasound for DVT	34/112 (30%) had DVT 110/112= Agreed High kappa coefficient (0.9%). One false positive. One where ED correct and vascular lab wrong- proved on venography	Included only the very experienced ED ultrasonographers (generalisability questionable)
Frazee et al 2001 USA	Convenience sample of adults presenting to ED with signs and symptoms of DVT over 18/12 period Exclusion: Prior DVT 76 patients 18 with DVT- 14 caught by ED	Prospective observational	ED performed 2PCUS vs vascular lab duplex scan. Positive, negative or indeterminate scan result	14/12 DVTs picked up by ED (2 neg, 2 indeterminate) Sensitivity 88.9% (CI 65.2- 98.6%) Specificity 75.9% (62.8%-86.1) PPV 53.3% (34.3- 71.7). NPV 95.7% (85.2-99.5)	No formal inclusion/exclusion criteria. Large number indeterminate scans with operator learning curve. Small sample size.
Jang et al 2004 USA	Convenience sample (72 patients) Exclusion: Previous DVT or recent scan results unknown. 23 positive for DVT	Prospective observational	Accuracy and pace of the resident-performed compression ultrasonography for the detection of proximal DVT	100% sensitivity (CI 82.2-100) 91.8% specificity (79.5-97.4)	Patient selection is not great. Reference standard not consistent. Used by beginners. 3 different reference tests: duplex venography, CT venography.
Blaivas et al 2004 USA	Exclusion: DVT dx before ED arrival or chronic DVT. Unstable, needing invasive testing. 156 patients (154 positive but seemingly all diagnosed previously)	Prospective observational	Time to disposition as the primary outcome. Accuracy as secondary outcome. 5 pre-trained EP’s using 2PCUS. Time recorded from triage to results of scan.	154/156 cases= agreement between ED and radiology (kappa coefficient of 0.9)	Variable prior experience of scanners. Unclear value of ED US when there is a 24 hour radiology cover. Unclear patient pathways/time to transfer to the radiology department.
Jacoby et al 2007 USA	Patients referred to the vascular lab with symptoms suggestive of DVT 121 symptomatic extremities 27 positive for DVT	Prospective clinical study	Accuracy of 2PCUS to detect acute deep-venous thrombosis by EM residents	121 examinations performed (8/9 cases of DVT identified by ED doctors 89% sensitivity; CI 55-100% 3 false positives (97% specificity; CI 95-100%)	Poor setting (vascular lab and not the ED). All patients referred to the vascular lab as ?DVT, not just ED patients. Small sample size.
Magazzini et al 2007 Italy	Patients presenting to ED with ?DVT when study doctors available (approx 20% of the time) 54/339 actually confirmed PEs and the doctor was doing tests around this	Prospective observational	Accuracy of below and above knee Doppler study in ED vs formal vascular lab study within 24-48 hours	399 examinations Sensitivity 100% (CI 96.2-100) Specificity 98.5% (CI 97.6-98.5)	Doctors available approx 20% of the time only. Didn't use a D-dimer to risk stratification.
Kline et al 2008 USA	Self-referred ED patients with at least one of: leg pain/ swelling/ asymmetry/ suspected PE. 27 positive for DVT	Prospective study	Accuracy of 3PCUS in ED vs Radiology dept whole leg scan. Patients followed up for 30 days for DVT/PE.	70% sensitivity (CI 60-80) 89% specificity (CI 83-94%)	Lower prevalence of DVT than other studies. Operator bias-scanner. knew risk classification. Lost follow up for 29 patients. Not the same reference test. ED scan with optional use of colour flow. ED scan for proximal clots only
Crisp et al 2010 USA	Convenience sample (188/238) of patients who presented with symptoms suggesting DVT 199 scans- 11 bilateral 45 positive for DVT	Prospective cross-sectional study	2PCUS in ED compared to Radiology dept duplex performed within 3 hours of the ED scan.	100% sensitivity (CI 92-100%) 99% specificity (CI 96-100%)	Operator bias due to wide range in number of scans per operator (1-29)
Shiver et al 2010 USA	Convenience sample of all patients >18y undergoing a PE work-up Left vague: reasons for PE workup? At doctor's discretion. 61 patients 6 positive for DVT	Prospective observational study	Accuracy of EM performed venous US for PE patients vs CTV	Sensitvity 86% Specificity 100%	Patients studied were PE not DVT Examiners are very experienced- generalisability affected. Small sample size. Their reference standard is not relevant to ED as CTV.
Farahmand et al 2011 Iran	Patients presenting with symptoms and signs suggestive of DVT including leg swelling and pain. Left vague. 74 patients 35 positive for DVT	Prospective observational study	Accuracy of ED 2PCUS vs. Radiology dept duplex (proximal leg)	Sensitivity 100% Specificity 100%	Small sample size. No clear exclusion criteria.
Abbasi et al 2012 Iran	81 consecutive patients suspected of DVT attending their hospital ?No of cases of confirmed DVT	Comparative prospective study	Accuracy of of conventional ultrasonography by emergency physicians with Doppler ultrasonography vs radiology physicians for diagnosis of DVT	Sensitivity 85.9% Specificity 41.2% Accuracy 84.6%	Not usual ED cohort. One doctor performs scans with supervision. A junior year(2nd) radiology resident performed the scan.
Torres-Macho et al 2012 Spain	Convenience sample of patients suspected of having DVT, hydronephrosis, cholecystitis and various cardiovascular diagnoses 76 cases of suspected DVT 26 confirmed	Prospective observational study	Initial accuracy of bedside ultrasound performed by EP for multiple indications after a short trained period	76 CUS performed Sensitivity 93% (CI 82-100) Specificity 98% (CI 94-100)	Several parts of the body were included in the study. Inconsistent test: 2/5 of the doctors only took the training class five months after the study had begun. Not blinded. Selection bias. Reference US is not well described.
Crowhurst et al 2013 Australia	Convenience sample 178 patients ?25 with DVT	Prospective study	Accuracy of 3PCUS performed by EM consultants for proximal lower extremity DVT vs Radiology Dept	77.8% sensitivity (CI 54-91%) 91.4% specificity (CI 84.9-95.3%)	Included only high experienced EP level (consultants) only
Poley et al 2014 Canada	Convenience sample of patients presenting with suspected DVT 237 patients (24 / 11.9% positive)	Cross-sectional prospective observational study	Evaluation of a new approach incorporating bedside limited-compression ultrasound (LC US) by emergency physicians (EPs) into the workup strategy for DVT	91% sensitivity (CI 70-98%) - very wide Specificity 97% (CI 92-99%) Proposed new algorithm	Applicability in doubt- the EPs were all experienced. Inclusion criteria not well described. Poor inter-rater reliability for certain components of Well's Score- the backbone of their study.
Kim et al 2016 USA	Convenience sample of ED patients (296 patients) presenting with signs and symptoms suggestive of DVT 50 positive for DVT	Prospective study and diagnostic test assessment	Accuracy and time limit of emergency physician performed limited compression ultrasound (LCUS) to test for (DVT)	86% sensitivity (CI 73-94%) Specificity 93% (CI 89-96%)	Long study period yet only 25% patients included- possibility of selection bias?. Delay in results. Poor patient follow-up.
Mary R Mulcare 2016 USA	Convenience sample with symptoms suggestive of DVT (not specified). 197 patients. 10% positive (About 20?)	Prospective observational study	Emergency Physicians (EPs) VS Radiology in reliability of lower limb US scanning for the diagnosis of DV and proximal great saphenous vein thrombosis. Effects of patient BMI and EP satisfaction with bedside US on sensitivity and specificity.	Overall sensitivity and specificity not stated but is very poor Concl: EPUS not suitable as a stand-alone study 257 (197 individual legs) 10% positive	Poor quality study. Vague with overall results. Confusing (90-95% agreement but really bad kappa coefficients). Level of experience of sonographers is unclear. Reference standard not described in enough detail (?above or below-knee).
Zitek et al 2016 USA	Convenience sample of patients (234) suspected of having DVT who also had a radiology ultrasound ordered 288 patients 28 had DVT	Prospective diagnostic test assessment study	Accuracy of EM resident-performed 2-point EPCUS. Competency of novice ultrasonographers using this technique.	Sensitivity 57.1% (CI 38.8-75.5) Specificity 96.1% (CI 93.8-98.5) High positive LR (14.9; CI 7.5-29.5) About 10% patients positive for DVT	Index test is not the advised one (2-point ECUS)- "straw man".
Pedraza Garcia et al 2018 Spain	Convenience sample of patients presenting to the ED with suspected DVT (D-dimer and Well's score integrated) 109 patients	Prospective cross-sectional study and diagnostic test assessment	Accuracy of emergency physicians who performed 3PCUS for suspected above-knee DVT within the context of using Wells score and D-dimer.	4/45= false negative (93.2% sensitivity: CI 83.8-97.3) 90% specificity (CI 78.6-95.7)	Good but could be more detailed about what it chooses. A 48-hour delay may have affected test characteristics .
Pujol et al 2018 France	232 patients presenting to ED 56 patients included 11 proximal confirmed DVTs and 5 distal on VDUS.	Prospective single-centre study, diagnostic test assessment	Assess the diagnostic performance of compression ultrasonography by emergency physicians (EPs) using a pocket-sized ultrasound device	100% sensitivity (72%;100%) 100% specificity (92%;100%)	Difficult to generalise as a single, experienced emergency physician. Early cessation of study- didn’t reach sample size required. Inadequate test detail.
Seyedhosseini et al 2018 Iran	50 patients presenting with symptoms suggestive of DVT to ED 14 positive for DVT in ED PCUS group and 17 in radiology performed group	Randomised clinical study	Compare the effect of point-of-care ultrasound on patients' disposition time, done by emergency physician versus radiologists	Secondary outcome: 100% compatibility between EP CUS and radiology-performed CUS	Only the secondary outcome is relevant. Small sample size. Unclear how many EPs performed the index test.
Zuker-Herman et al 2018 Israel	Convenience sample of 195 patients to ED with symptoms of DVT 48 positive for DVT	Prospective study	Compare the sensitivity and specificity of 2PCUS and 3PCUS for diagnosis of lower extremity DVT in an ED management	2-point: Sensitivity 82.76%, Specificity 98.52% 3-point: Sensitivity 90.57%, Specificity 98.52%	Unblinded study. Unclear time Discrepancy between radiologist performed and ED PCUS.
Jahanian et al 2019 Iran	Convenience sample of 72 patients presenting to ED with symptoms of DVT 26 patients found to be positive for DVT	Cross-sectional prospective diagnostic study	Accuracy of 3PCUS performed by EM resident for diagnosis of DVT	Sensitivity 52.8%, Specificity 85.7% Confidence intervals not stated in study	Suggested cause for low sensitivity was for inexperienced staff performing scans.
Dehbozorgi et al 2019 Iran	240 patients with history suspicious for DVT 105 patients positive for DVT	Prospective observational	Accuracy of 3PCUS in diagnosis of DVT by ED residents vs the results of duplex US (whole-leg compression ultrasound) by radiology residents	Sensitivity 100% (95%CI 96.55%-100%) Specificity 93.33% (95% CI, 87.72%-96.91%) NPV 100% PPV 92.11%	Supervised by attendants and so difficult to interpret the level of input from senior clinicians.
Lee et al 2019 Republic of Korea	Patients with suspected DVT in 17 studies(2-point, 1337 patients in 9 studies; 3-point, 1035 patients in 8 studies)	Systemic review and meta-analysis	Accuracy of 2PCUS and 3PCUS performed by an emergency physician in the diagnosis of lower extremity DVT. Compared the false-negative rates of both techniques. Compared accuracy to radiologists.	2PCUS had similar pooled sensitivity (0.91) and specificity (0.98) as 3PCUS (sensitivity, 0.90 and specificity, 0.95). POCUS-trained attending emergency physicians perform the initial 2-point POCUS effectively and accurately diagnose DVT.	15 studies only used follow-up US by radiologists as the reference standard. All studies had an unclear risk of bias as the mean interval between POCUS and the reference standard was not reported.
Canacki et al 2020 Turkey	266 patients with a clinical suspicion of DVT, underwent POCUS and were monitored by the radiology department via US or venography	Retrospective observational study	Assess the diagnostic value of POCUS in DVT diagnosis. Compare 2 POCUS by a senior emergency resident to radiology US or venography.	2 POCUS had a sensitivity of 93%, specificity of 93%, positive predictive value of 83% and a negative predictive value of 97%.	Retrospective study. Classification bias due to lack of the same diagnostic performance with lower RUS and CT venography.
Hylmar et al 2021 Netherlands	138 patients with clinical suspicion of DVT (28 positive) 2 PCUS	Single-blind cohort study	Primary outcome: Agreement between the finding of US performed by ED clinicians versus radiology	Absolute agreement 94% between ED performed 2 PCUS and radiology (kappa 0.87)	Small quantity of positive patients. US performed by either ED physicians or residents. Looked at agreement rather than sensitivity/ specificity

Comment(s)

This review examines the accuracy of emergency physician-performed POCUS to identify DVT when compared to gold-standard radiology-performed imaging. Patients presenting to the ED with signs and symptoms of DVT may be managed safely without hospital admission. Emergency Physician-performed POCUS presents the opportunity to facilitate the rapid assessment, triage and possible discharge of this cohort. POCUS for DVT in the ED is probably best applied as part of a rule-in strategy. Absence of occlusive thrombosis therefore should not rule out this diagnosis. If clinical pretest probability is low and sonographic signs of DVT are not present then it may be reasonable to withhold anticoagulant therapy entirely or until gold standard imaging is available. In addition, the use of POCUS for DVT may also help identify alternative pathology such as cellulitis, abscess, superficial thrombophlebitis, popliteal cysts or muscular tear/ haematoma. In this short review, scanning protocols differed across many of the studies. The region of interest that was examined was not standardized in this review. Different imaging techniques were also used ranging from 2-point and 3-point compression techniques to color & duplex studies. On account of this degree of heterogenicity, it is difficult to carry out a comparative quantitative analysis of the 26 studies. In general, the performance of a 2 point compression protocol did not seem to differ significantly from a 3 point compression protocol. It seems intuitive that the more extensive approach would yield better results. The authors therefore recommend (at least) a 3 point compression scanning protocol when examining for DVT. Operators had a wide level of training using POCUS ranging from newly-qualified emergency medicine residents to experienced emergency physicians accredited to perform this application. In general, when experienced physicians carried out the point of care ultrasound examination, reported sensitivity and specificity were usually high with narrow confidence intervals. Less experienced operators reported lower sensitivity and/ or wide confidence intervals.

Clinical Bottom Line

In the hands of well-trained emergency physicians, POCUS is generally quick and accurate when used as a rule in-test for DVT. It also may be useful as part of the risk stratification process for the administration of anti-thrombotic medication.

References

1. Michael Blaivas Lower-extremity Doppler for deep venous thrombosis--can emergency physicians be accurate and fast? Academic Emergency Medicine 2000 Feb;7(2):120-6
2. Bradley W Frazee Emergency Department compression ultrasound to diagnose proximal deep vein thrombosis The Journal of Emergency Medicine 2001 Feb;20(2):107-12.
3. Timothy Jang Resident-performed compression ultrasonography for the detection of proximal deep vein thrombosis: fast and accurate Academic Emergency Medicine 2004 Mar;11(3):319-22.
4. Daniel Theodoro Real-time B-mode ultrasound in the ED saves time in the diagnosis of deep vein thrombosis (DVT) The American Journal of Emergency Medicine 2004 May;22(3):197-200.
5. Jeanne Jacoby Can emergency medicine residents detect acute deep venous thrombosis with a limited, two-site ultrasound examination? The Journal of Emergency Medicine 2007 Feb;32(2):197–200.
6. Simone Magazzini Duplex ultrasound in the emergency department for the diagnostic management of clinically suspected deep vein thrombosis Academic Emergency Medicine 2007 Mar;14(3):216-20.
7. Jeffrey A Kline Emergency clinician-performed compression ultrasonography for deep venous thrombosis of the lower extremity Annals of Emergency Medicine 2008 Oct;52(4):437-45.
8. Jonathan G Crisp Compression ultrasonography of the lower extremity with portable vascular ultrasonography can accurately detect deep venous thrombosis in the emergency department Annals of Emergency Medicine 2010 Dec;56(6):601-10.
9. Stephen A Shiver Prospective comparison of emergency physician-performed venous ultrasound and CT venography for deep venous thrombosis The American Journal of Emergency Medicine 2010 Mar;28(3):354-8.
10. Shervin Farahmand The accuracy of limited B-mode compression technique in diagnosing deep venous thrombosis in lower extremities The American Journal of Emergency Medicine 2011 Jul;29(6):687-90.
11. Saeed Abbasi Comparison of diagnostic value of conventional ultrasonography by emergency physicians with Doppler ultrasonography by radiology physicians for diagnosis of deep vein thrombosis Journal of Pakistan Medical Association 2012 May;62(5):461-5.
12. Juan Torres-Macho Initial accuracy of bedside ultrasound performed by emergency physicians for multiple indications after a short training period The American Journal of Emergency Medicine 2012 Nov;30(9):1943-9.
13. Thomas D Crowhurst Sensitivity and specificity of three-point compression ultrasonography performed by emergency physicians for proximal lower extremity deep venous thrombosis Emergency Medicine Australasia 2013 Dec;25(6):588-96.
14. Rachel A Poley Estimated effect of an integrated approach to suspected deep venous thrombosis using limited-compression ultrasound Academic Emergency Medicine 2014 Sep;21(9):971-80.
15. Daniel J Kim Test Characteristics of Emergency Physician-Performed Limited Compression Ultrasound for Lower-Extremity Deep Vein Thrombosis The Journal of Emergency Medicine 2016 Dec;51(6):684-690.
16. Mary R Mulcare Interrater reliability of emergency physician-performed ultrasonography for diagnosing femoral, popliteal, and great saphenous vein thromboses compared to the criterion standard study by radiology Journal of Clinical Ultrasound 2016 Jul 8;44(6):360-7.
17. Tony Zitek Mistakes and Pitfalls Associated with Two-Point Compression Ultrasound for Deep Vein Thrombosis The Western Journal of Emergency Medicine 2016 Mar;17(2):201-8.
18. Jorge Pedraza García Comparison of the Accuracy of Emergency Department-Performed Point-of-Care-Ultrasound (POCUS) in the Diagnosis of Lower-Extremity Deep Vein Thrombosis The Journal of Emergency Medicine 2018 May;54(5):656-664.
19. Sarah Pujol Compression with a pocket-sized ultrasound device to diagnose proximal deep vein thrombosis The American Journal of Emergency Medicine 2018 Jul;36(7):1262-1264.
20. Javad Seyedhosseini Impact of point-of-care ultrasound on disposition time of patients presenting with lower extremity deep vein thrombosis, done by emergency physicians Turkish Journal of Emergency Medicine 2018 Mar; 18(1): 20–24.
21. Rona Zuker-Herman Comparison between two-point and three-point compression ultrasound for the diagnosis of deep vein thrombosis The Journal of Thrombosis and Thrombolysis 2018 Jan;45(1):99-105.
22. Fatemeh Jahanian Diagnostic Accuracy of a Three-point Compression Ultrasonography Performed by Emergency Medicine Resident for the Diagnosis of Deep Vein Thrombosis: a Prospective Diagnostic Study Acta Informatica Medica 2019 Jun;27(2):119-122.
23. Afsaneh Dehbozorgi Accuracy of three-point compression ultrasound for the diagnosis of proximal deep-vein thrombosis in emergency department Journal of Research in Medical Sciences 2019; 24: 80.
24. Ju Hyung Lee Comparison of 2-point and 3-point point-of-care ultrasound techniques for deep vein thrombosis at the emergency department: A meta-analysis Medicine (Baltimore) 2019 May;98(22):e15791.
25. Mustafa Emin Canakci Diagnostic value of point-of-care ultrasound in deep vein thrombosis in the emergency department Journal of Clinical Ultrasound 2020 Nov;48(9):527-531.
26. Hylmar E Elsenga Agreement between emergency physicians and radiologists for the diagnosis of deep venous thrombosis with compression ultrasound: a prospective study European Journal of Emergency Medicine 2021 Jan 1;28(1):25-28.