The Evaluation of DVT –Bedside Ultrasound Diagnosis & Evaluation in Emergency setting

5-6th September 20143rd National Venous Thromboembolism (VTE) Congress

Ahmad Suhailan Mohamed Hospital Serdang

Scope• The challenges to diagnose DVT in the

emergency setting

• A practical solution

BEDSIDE ULTRASOUND

• Challenges to apply this solution in ED setting

Scenario in the ED setting

• 45yo Female• Pain, swelling & redness of the

Right leg & calve

• Travelled from Sabah to KL

• Upon examination – Right calve & leg swollen & tender on palpation

Scenario in the ED setting

DDx – DVT or Cellulitis

• Friday evening• URGENT Lower Limb

Ultrasound ?• Who to Refer ?

– Ortho / surgical– Medical / Vascular

• Wants Blood result – TW , D-Dimer

• OVERCROWDED Emergency Department

Scenario in the ED setting

Discharge / Admit?Treat for DVT?

Patient at risk PULMONARY EMBOLUS

• DVT presents with non-specific symptoms & Physical examination alone cannot exclude DVTWells PS, Hirsh J, Anderson DR, et al. Accuracy of clinical assessment ofDVT . Lancet. 1995;345: 1326-1330.

• Up to 60% of untreated DVTs progress to PE over 50,000 deaths each yearMoser KM, Fedullo PF, LitteJohn JK, et al. Frequent asymptomatic pulmonary embolism in patients with deep venous thrombosis. JAMA 1994;271:223–5.

• The Challenge in ED Setting to diagnose, treat, & disposition patients in a timely manner

• Need efficient & safe ways to rapidly diagnose these patients

Probable Solution

• ULRASONOGRAPHY has emerged as the FIRST LINE IMAGING modality diagnosis of DVT

• Non-invasive• Portable• BEDSIDE – real time visualisation• Immediate clinical decision making

• The concept is simple: failure of veins to compress Indirect evidence presence of thrombus

Lower Extremity Ultrasound

a) 2 point compression• Scan only at the groin &

popliteal fossa• Easy to train• Easy & quick to perform• Reliable method

b) Extended compression• groin till popliteal fossa• Easy to perform

c) Whole Leg compression• Whole LL from groin till calf• femoral & popliteal veins &

their tributaries• Exhaustive, takes time• Difficult to identify calf

veins• Difficult to train

• COLOUR DOPPLER US - the presence of flow throughout the vessels

• DUPLEX ultrasound Compression US + COLOUR & FLOW Doppler US Effective first-line method of detecting DVT (sensitivity 91-96%, specificity 98-100%)

the standard of care in diagnosing proximal LE DVT

Lower Extremity Ultrasound

Proximal DVT vs Distal DVT• Majority of thrombi are present at distinct

venous segments • Common femoral, deep femoral, &

superficial femoral vein junction & popliteal region is sufficient to diagnose the presence of DVT

• The presence of isolated thrombus apart from these areas is rare

• DVT do not form in isolated small plugs • Grow from smaller to larger vessels• Either propagate proximally or resolve

2 point compression

• Compression applied only iliofemoral junction & popliteal vein• Color Doppler for detection of the vessels (not to assess flow)

• ? Risk of missing segmental DVT’s thrombus limited to one section of the deep vein

• Studies has shown the sensitivity of the abbreviated approach to be equal to the complete exhaustive approach, both reaching 100% sensitivity for proximal DVT’sBirdwell BG; annals of internal medicine 128:1-7, 1998Poppiti R;J Vasc Surg 22:553-557, 1995Heijboer H; N Engl J Med 329:1365-1369, 1993ATS Clinical Practice Guideline: Am J Respir Crit Care Med 1999; 160:1043-1066

Probe

• High frequency linear transducer 5-10 MHz• Better resolution• Flat surface is ideal for achieving adequate

compression

• Mainly B mode imaging• Adequate gel• Adjust Depth & TGC

• Colour flow / Pulse wave Doppler optional

LE Ultrasound for DVT

• Patient supine with the head of the bed raised to 45° to increase venous distension of the legs.

• Flex the patient's leg at the knee, externally rotate the hip to allow the best exposure of the junction of the common, deep, & superficial femoral veins as well as the popliteal fossa.

Start the examination as proximally as possible, ideally

at the inguinal ligament

Once the CFV & CFA are identified, scan distally until the great saphenous vein (GSV) emptying into the CFV is seen.

The probe is moved distally to the bifurcation of the femoral vein into the superficial femoral vein & deep femoral vein

• At each point, apply firm compression perpendicularly to achieve complete collapse of the vein.

• The lumen of the vein must disappear completely in order to exclude the presence of a clot

A CLOT seen as echogenicity within the lumen

Most cases only evidence of a DVT will be the inability to compress the vein fully.

2 point compression compressing a short segment of vasculature, typically 3-4 cm, with approximately 3 or 4 compressions

A patent vein will collapse completely

5) Imaging of the popliteal vein is performed next with the knee slightly flexed & with the hip slightly externally rotated

Common Pitfalls

• Challenging subjects• Confusion on vessel anatomy• Calf vein DVT• Pelvic vein DVT• Mistaking Lymph Nodes for DVT• Chronic DVT

B-Posterior tibial veins; C-Peroneal veins; D-Anterior tibial veins; E-Popliteal vein; F-Femoral vein; G-Deep femoral vein; H-Common femoral vein.

Are EP accurate

What is the Accuracy of Emergency Physician -performed Ultrasonography for DVT?

Meta-analysis – 16 studies (MEDLINE,EMBASE, EM & Heamatology conference proceding up to 2012)

Sensitivity 96%Specificity 97%

West JR, Chilstrom ML; Systematic Review Snapshot, Annals of Emergency Medicine 2014

Supports EP-performed ultrasonography by well trained physicians to diagnose

DVT in carefully selected patients

How much training is needed

• EP –performed 2-point compression US of LE with a portable US machine, conducted in the ED accurately identified the presence & absence of proximal LE DVT– Sensitivity 100% Specificity 99%

• EP had a 10-minute bedside training session Any physician with limited ultrasonographic experience can

easily acquire the skills necessary to perform ED 2-point compression ultrasonography for proximal LE DVT

Crisp JG et al [Ann Emerg Med. 2010;56:601-610] Compression Ultrasonography of the Lower Extremity With Portable Vascular Ultrasonography Can Accurately Detect DVT in ED

• 20 EPs underwent 2 hours of training on how to perform a 2-point compression US

• Performed 80 examinations on patients in which DVT was suspected

• EP US to be 100% sensitive & 98.2% specific in the diagnosis of DVT compared with traditional radiology US

Wong HE, Moore C, Skrupky R, et al. Accuracy of emergency physician compression ultrasonography and D-dimer in the bedside diagnosis of DVT. Ann Emerg Med 2003;42:S89–S90

How much training is needed

• The exact amount of training & experience required to safely perform point-of-care focused LE US tro DVT unknown

• Appropriate LOCAL quality assurance & competency testing may ↑physician confidence levels & ↑ diagnostic accuracy

• 2009 American College of Emergency Physicians minimum requirement of 25 DVT scans are needed, after a completion of a 2 day course

Tayal V, Blaivas M, Mandavia D, et al. Policy statement: emergency ultrasound guidelines. Ann Emerg Med. 2009;53:550-570.

How much training is needed

• MALAYSIAN SOCIETY OF CRITICAL AND EMERGENCY SONOGRAPHY (SUCCESS) - internationally recognized certification courses in collaboration with other organization(WINFOCUS International)

http://www.criticalultrasoundmalaysia.org

How much training is needed

Time taken EP to perform US exam

• EM residents can perform a detailed multiple-point proximal LE DVT compression US examination in < 12 minutesJang T, Docherty M, Aubin C, et al. Resident-performed compression ultrasonography for the detection of proximal deep venous thrombosis: fast and accurate. Acad Emerg Med. 2004; 11:319-322.

• The 2- compression technique allows EP to determine in < 4 minutes

• 98% correlation with the radiology-performed complete duplex ultrasound examination

Blaivas M, Lambert M, Harwood R, et al: Lower-extremity Doppler for deep venous thrombosis—can emergency physicians be accurate and fast? Acad Emerg Med 2000;7:120-126

Benefits Bedside US

• Bedside Ultrasonography (B mode) performed by EP in ED saves time to diagnose DVT

Rapid disposition – Shorter ED stayLess time spent by ED staff on patients who are waitingPatient can be rapidly treated Improving ED efficiency

• Theodoro D, Blaivas M, Duggal S, et al. Real-time B-mode ultrasound in the ED saves time in the diagnosis of deep vein thrombosis (DVT). Am J Emerg Med. 2004;22:197-200.

In Summary …

• ULTRASOUND useful diagnostic tool in DVT suspected pt

• The 2-point compression US & whole leg color coded comprehensive US are equivalent for diagnosing lower-extremity DVT

• EP can accurately & rapidly perform bedside LE compression US to detect DVT

• Time to train ? EP can possibly master this skill

Salient points

• Using ultrasound in the evaluation for DVT decrease time to definitive care decrease the length of stay in ED

Bedside LE US to rule out DVT ….• is easy for emergency physicians to learn, • is accurate for diagnosing & ruling out LE DVT in the ED, • and can decrease length of stay,• cut costs, • and probably save lives

Thank You

References• Pezzullo JA, Perkins AB, Cronan JJ: Symptomatic deep vein thrombosis:

diagnosis with limited compression. US Radiology 1996;198:67-70

• Heijboer H, Buller HR, Lensing AWA, et al: Comparison of real time compression ultrasonography with impedance plethysmography for the diagnosis of deep-vein thrombosis in symptomatic patients. N Engl J Med 1993;329:1365-1369

• Clinical & Practice management; Focus On: Emergency Ultrasound For Deep Vein Thrombosis; ACEP News , American College of Emergency Medicine, March 2009http://www.acep.org/Clinical---Practice-Management/Focus-On--Emergency-Ultrasound-For-Deep-Vein-Thrombosis/

• WINFOCUS Lecture on DVT; USLS BL-1 Provider; winfocus.org

3 point compression

• Simplified three-point compression technique that concentrates on the evaluation of those areas with highest turbulence and at greatest risk for developing thrombus:

• 1) the common femoral vein at the saphenous junction, • 2) the proximal deep and superficial femoral veins, and • 3) the popliteal vein

• A more recent article found that in a heterogeneous group of emergency clinicians, including residents and mid-level emergency providers with different stages in training in

ultrasound, the accuracy rate is closer to 85%.5

Kline JA, et al. Emergency-clinician performed compression ultrasonography for deep venous thrombosis of the lower extremity. Ann Emerg Med 2008; 52:437-45.

• A recent meta-analysis done by Burnside et al [20] showed a 95% sensitivity of EPPU of the lower extremity when compared to radiology performed scans.Burnside PR, Brown MD, Kline JA. Systematic review of emergency physician-performed ultrasonography for lower-extremity deep vein thrombosis. Acad Emerg Med 2008;15(6):493-8.

References

Use Wells clinical prediction rule and D-dimer assays to determine your pre-test clinical probability. (See clinical algorithm.) If you have moderate to high suspicion for DVT but a negative initial screening exam, have the patient return within 1 week for a repeat ultrasound or perform contrast venograph

Calve DVT• In addition, EPPU does not provide an assessment of the calf veins. • CT venography may occasionally note a thrombosis distal to the

trifurcation of the popliteal vein, but the absence of this finding certainly does not rule out distal thrombosis.

• Currently, there is no consensus on the clinical significance of calf vein thrombosis and no agreement on what, if any, treatment is warranted

• Righini M. Is it worth diangnosing and treating distal deep venous thrombosis? No. J Thromb Haemost 2007;5(Suppl 1):55-9.

• Schellong SM. Distal DVT: worth diagnosing? Yes. J Thromb Haemost 2007;5(Suppl 1):51-4.