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
Use a linear transducer and choose the DVT setting
Squirt gel on the entire thigh instead of the probe so you don’t have to repeatedly re-gel the probe
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.
While the saphenous vein is considered a superficial vein, clots close to the sapheno-femoral junction should be treated with anticoagulation.
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
Move onto compression of the popliteal region where the popliteal vein is on top of the artery (“pop on top”)
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