VOTW: DVT

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This week’s VOTW is brought to you by Drs Kim, Nguyen and Sanghvi!

A patient with a previous history of DVTs no longer on anticoagulation presented with 4 days of right lower extremity pain, shortness of breath and chest pain. A POCUS of the lower extremities showed…

Clip 1 shows a non-compressible R common femoral vein containing echogenic material concerning for a DVT. The clot is seen extending into the saphenous vein as it takes off from the common femoral vein. Clip 2 shows the L common femoral vein also with a DVT extending into the saphenous vein. You can see that there is enough force applied with the probe to compress the artery completely, yet the vein is not fully compressed.

Chronic DVT

The appearance of these DVTs suggest that they are chronic. In general, chronic DVTs are more echogenic and have a more ragged appearing edge. Over time, DVTs tend to recanalize centrally. In image 1 below, you can see there is some areas that are recanalizing outlined in green. Image 2 shows an illustration of acute vs chronic DVTs.

DVT with area of recannalization

Acute vs Chronic DVTs

Acute DVT

An acute DVT generally has smoother edges and is less echogenic than a chronic DVT. Some acute DVTs cannot be seen with ultrasound and their presence can only be identified by the inability to collapse the vessel completely. If you are placing enough pressure to collapse the artery but the vein is not yet collapsed, this is concerning for a DVT.

Tips and tricks for lower extremity DVT studies

  1. Use a linear transducer and choose the DVT setting

  2. Squirt gel on the entire thigh instead of the probe so you don’t have to repeatedly re-gel the probe

  3. Start in the inguinal crease and identify the take-off of the saphenous vein. This is a common site for a DVT and is the proximal starting point for our ED performed limited compression studies. Compress and take a clip here.

  4. While the saphenous vein is considered a superficial vein, clots close to the sapheno-femoral junction should be treated with anticoagulation.

  5. The common femoral vein bifurcates into the deep femoral vein (DFV) and superficial femoral vein (SFV). The DFV courses deep and is difficult to evaluate. The SFV is a mis-nomer and is actually a deep vein. Follow the SFV as far as you can down the thigh compressing every 2cm

  6. Move onto compression of the popliteal region where the popliteal vein is on top of the artery (“pop on top”)

  7. Compressing obliquely is a common reason the vein does not compress completely resulting in a false positive interpretation. Use your non-probe hand to assist in compressing the vein perpendicularly to the femur.

Back to the patient
A CTA chest was negative for pulmonary embolism and patient was discharged on oral anticoagulation and outpatient follow up.

Happy Compressing and De-compressing,

Your Sono Team

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DVT

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Definition

·      Proximal DVT: Clot formation in the popliteal vein or higher.

·      Distal DVT: Isolated clot in the calf veins (anterior/posterior tibial and peroneal veins)

 

Signs and Symptoms

·      Cramping or calf fullness

·      Lower extremity: unilateral leg swelling, edema, redness (can resemble cellulitis) and pain

·      Upper extremity: arm swelling, finger swelling (ill-fitting rings)

 

Pre-test Probability

 Wells Score

Dr. Wells – “The model should be applied only after a history and physical suggests that venous thromboembolism is a diagnostic possibility. it should not be applied to all patients with chest pain or dyspnea or to all patients with leg pain or swelling. This is the most common mistake made.”

Ultrasound

·      Diagnostic method of choice

·      Multiple Systems: 3-point system (common, superficial femoral veins, and popliteal veins) and whole leg

·      Low pretest probability

o   A negative 3-point US effectively rules out DVT

o   A negative whole leg US effectively rules out DVT

 

·      Moderate to High pretest probability

o   Ultrasound does not rule out DVT, must add D-dimer or repeat ultrasound in 1 week.

 

CT Venogram

·       Can be added on to CTPA that’s being performed for PE.

·       Identifies DVT in the absence of PE in up to 2% of patients

 

MRI

·       Limited utility due to cost, availability, and no superiority to ultrasound

·       Useful for evaluation of pelvic veins and vena cava

Management 

  • Proximal DVT without history of cancer

    • Oral anticoagulant alone (dabigatran, rivaroxaban, apixaban or edoxaban (NOAC)) preferred over a vitamin K antagonist (VKA) (Grade 2B recommendation)

    • VKA preferred to low-molecular weight heparin (LMWH) (Grade 2C recommendation)

    • Duration of treatment: 3 months for 1st clot (Grade 1B recommendation)

  • Proximal DVT with cancer

    • LMWH preferred to VKA therapy, dabigatran, rivaroxaban, apixaban or edoxaban (Grade 2C recommendation)

    • Duration of treatment: 3 months for 1st clot (Grade 1B recommendation)

  • Distal DVT (isolated)

    • The significance of isolated distal DVTs is unknown.

    • It is unclear whether systemic anticoagulation is beneficial to the patient with these clots

    • Risk factors for extension

      • D-dimer is positive (particularly with larger elevations)

      • Extensive thrombosis (> 5 cm in length, multiple veins, > 7 mm diameter)

      • Proximity to proximal veins

      • No reversible provoking factor for the DVT

      • Active cancer

      • History of VTE

      • Admitted to the hospital

    • Absence of severe symptoms and no risk factors for extension

      • Serial imaging over 2 weeks preferred to anticoagulation (Grade 2C recommendation)

      • No established role for providing antiplatelet therapy (i.e. aspirin) alone in these cases but a reasonable intervention

    • Presence of severe symptoms or risk factors for extension

      • Anticoagulation preferred to serial imaging (Grade 2C recommendation)

      • Anticoagulation choices same as for proximal DVT (Grade 1B recommendation)

  • Superficial Thrombophlebitis

    • Saphenous vein clots above the knee can spread into deep venous system via the saphenous-femoral junction

    • Initial treatment with NSAIDs, warm compresses and compression stockings

    • Repeat US in 2-5 days and start anticoagulation if clot extending

  • Catheter-Directed Thrombolysis (CDT)

    • Does not show substantial benefits in most patients with proximal DVT and likely increases risk of major bleeding

    • Patients with iliofemoral DVT and a low risk of bleeding may benefit from CDT

Disposition

·       Discharge

Consider if all the following are present:

o   Ambulatory

o   Hemodynamically stable

o   Low risk of bleeding in patient

o   Absence of renal failure

o   Able to administer anticoagulation with appropriate monitoring

o   Able to arrange for 2-3 days follow-up

·       Admit

o   Ileofemoral DVT that is a candidate for thrombectomy (should have the following):

§  Acute iliofemoral DVT (symptom duration <21 days)

§  Low risk of bleeding

§  Good functional status and reasonable life expectancy

o   Phlegmasia Cerulea Dolens

§  DVT that causes phlegmasia cerulea dolens requires rapid action

§  Anticoagulate, place limb at a neutral level, and arrange for consultant-delivered catheter-directed thrombolysis.

§  Transfer if don’t have services or can’t be arranged within 6 hours, consider systemic fibrinolytics if there are no absolute contraindications.

§  One regimen is 50 to 100 milligrams of alteplase infused IV over 4 hours.

o   High risk of bleeding on anticoagulation

o   Significant comorbidities

o   Symptoms of concurrent PE

o   Recent (within 2 weeks) stroke or transient ischemic attack

o   Severe renal dysfunction (GFR < 30)

o   History of heparin sensitivity or HIT

o   Weight > 150kg

o   Upper extremity DVT

 

References

https://coreem.net/core/deep-venous-thrombosis-dvt/

https://journal.chestnet.org/article/S0012-3692(15)00335-9/fulltext

https://wikem.org/wiki/Deep_venous_thrombosis

Tintanillis Emergency Medicine Comprehensive Study Guide

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