Interpretation of peripheral venous duplex testing.

Venous duplex ultrasound and plethysmography are used to evaluate patients for suspected deep venous thrombosis (DVT) or venous insufficiency symptoms. Testing can provide clinicians with detailed information on location, extent, and severity of venous conditions before and after treatment. Duplex ultrasound can image the venous system from the vena cava to the peripheral veins, including veins of the calf musculature, and is the recommended technique to diagnose DVT. Accurate interpretation of venous testing requires an understanding of venous hemodynamics, including normal flow phasicity with cardiac and respiratory motion and the changes produced by acute DVT. Duplex scanning provides a roadmap of vein anatomy similar to contrast venography and essential hemodynamic information about the presence of proximal obstruction, vein valve function, and perforator vein reflux. Indications for testing include the diagnosis of acute/chronic DVT and evaluation of patients with venous insufficiency manifested as edema, varicose veins, or ambulatory venous hypertension. Venous plethysmography, an indirect physiologic test, can be used to estimate severity of obstructive or reflux venous pathophysiology and document improvement in venous hemodynamics after intervention. Using criteria based on ultrasound imaging and physiologic testing, venous conditions producing a swollen or painful limb can be accurately determined and aid in appropriate treatment selection.