This document provides an overview of deep venous ultrasound for detecting deep vein thrombosis (DVT). It describes the indications, limitations, and standard ultrasound protocol for a focused exam. Key points include: DVT has a high incidence in the US and can lead to pulmonary embolism; ultrasound is a good diagnostic tool as it is non-invasive, portable, and low cost; the standard protocol focuses on assessing compressibility of the common femoral and popliteal veins; findings suggestive of DVT include non-compressibility, echogenic material within the vein, and decreased blood flow despite augmentation.

1. Deep Venous Ultrasound University of Florida-Jacksonville Department of Emergency Medicine Petra Duran-Gehring, M.D.

2. Objectives Describe the indications and limitations of focused ultrasound for the detection of deep venous thrombosis Understand the standard ultrasound protocol when performing a focused exam Define the relevant local anatomy Develop an understanding of doppler physics and instrumentation Recognize the relevant focused findings and pitfalls when evaluation for deep vein thrombosis

3. Deep Venous Thromboembolism Incidence in U.S.: 1 in 1000 people/year 10% of proximal DVTs will lead to PE 50% of untreated proximal DVTs will lead to PE within 3 months >80% of PEs due to DVTs

4. DVT Risk Factors Recent Trauma Recent Surgery Immobility Cancer Estrogen Pregnancy OCPs Prior DVT/PE Family history of hypercoagulabity Protein C or S deficiency Factor V lieden or Antithrombin III deficiency Antiphospholipin or anticardiolipin antibody Homocysteine Lupus anticoagulant

5. Physical Exam Unilateral leg swelling Tenderness to palpation Redness Warmth Palpable cords- rare Homann’s sign- rare Pratt’s sign Poor sensitivity and Specificity

6. Lower Extremity DVT Popliteal 10% Popliteal + Superficial Femoral 42% Popliteal + Superficial Femoral + Common Femoral 5% All proximal vessels 35%

7. DVT Diagnostics Contrast Venography Former gold standard Time consuming IV dye exposure Plethysmography CT MRI Ultrasound Low cost Portable Non-invasive

8. Ultrasound Protocols Duplex Comprehensive Color flow Doppler Time consuming (about 45 mins) Limited Compression Focused technique Bedside exam Look for clot only in Common femoral vein Popliteal vein

9. Limited Compression Ultrasound Focus on proximal veins Thrombi distal to popliteal rarely embolize Distal thrombi may propagate to popliteal Therefore, if DVT suspected, must rescan in 3-5 days Clot is identified by the lack of normal compressibility of the vein Proven to be as accurate as Duplex US and better than plethysmography in finding proximal clots

10. Lower Extremity Venous Anatomy Common Femoral Common Femoral Superficial (saphenous) Deep Deep Femoral (Profunda) Superficial Femoral Popliteal Anterior Tibial Peroneal Posterior Tibial Deep Femoral Superficial Femoral Popliteal

11. Common Femoral Anatomy Common Femoral Vein Femoral Artery

12. Femoral Junction Anatomy Common Femoral Vein Saphenous Vein Femoral Artery

13. Femoral Bifurcation Anatomy Common Femoral Vein Femoral Artery ProfundaFemoris

14. Superficial Femoral Anatomy Superficial Femoral Vein Femoral Artery

15. Popliteal Anatomy Popliteal Vein Popliteal Artery

16. Scanning Technique Linear array probe 6-10 mHz Medium footprint If pt is obese, may need to use a lower frequency sector probe Positioning Reverse trendelenberg Semi-sitting with hips in 30 degrees flexion

17. Ultrasonic DVT Findings Non-compressibility Echogenic material with lumen Decreased blood flow Despite augmentation

18. Compression Compress vein using transducer Complete apposition of the vein walls needed to rule out DVT If compression is not achieved with pressure sufficient to deform adjacent artery, thrombus present

19. Common Femoral Pt placed in supine position Leg externally rotated Probe indicator to pt’s right

20. Femoral Vein Place probe in inguinal crease Use color flow doppler to distinguish vessels Scan from CFV through the SFV Compress as you go

21. Femoral Vein DVT

22. Popliteal Position Prone Decubitus Seated on edge of gurney Knee bent to increase venous filling Reverse trendelenburg Probe indicator to pt’s right

23. Popliteal Place probe 10-12 cm above bend in knee Use color flow doppler to distinguish vessels Scan through to the trifurcation of the popliteal Compress as you go

24. Popliteal Vein DVT

25. Scan Protocol Begin by palpating femoral pulse Place transducer over inguinal ligament with probe indicator to pt’s right Scan through the common femoral to the bifurcation (about 10 cm) Move to posterior knee bend Scan through popliteal to the trifurcation Take clips to illustrate compressibility May need to image the contralateral side if results questionable

26. Pearls Augmentation of flow by compressing the calf can help distinguish the vein from artery Optimize gain to best see the vascular system If case equivocal, scan other side and compare May scan through the superficial femoral vein is clinical suspicion is high

27. Questions???