How do you differentiate superficial venous reflux from deep venous reflux on duplex?

• A. Reflux in superficial veins (saphenous system) versus reflux in deep veins (femoral, popliteal); deep reflux is more clinically significant for DVT risk.
• B. Reflux always occurs in deep veins first before superficial veins become abnormal.
• C. Superficial reflux indicates high DVT risk but deep reflux does not.
• D. Reflux in perforator veins only is clinically significant.

Answer: (B)

The key idea is to identify where the backward flow occurs. On duplex, you distinguish superficial from deep venous reflux by the anatomic compartment showing the reflux. Reflux confined to the superficial veins (for example, the great or small saphenous veins) is superficial venous reflux. Reflux that originates in the deep system (femoral, popliteal, or other deep veins) is deep venous reflux. In practice, you provoke reflux with maneuvers and look at how long retrograde flow lasts in each vessel after release; the location of that reflux—superficial versus deep—determines the diagnosis and its clinical implications. Deep venous reflux generally carries more significance due to its association with DVT risk and chronic venous insufficiency, whereas superficial reflux can occur independently and is often related to varicose veins. Perforator reflux can occur with either system but doesn’t define the superficial-versus-deep distinction.