Duplex ultrasound is the best method for evaluating lower extremity chronic venous insufficiency [3]. It has replaced other imaging and physiologic modalities such as venography (phlebography) and plethysmography as the most cost-effective, accessible, and accurate diagnostic tool. When further anatomic definition is needed, particularly above the inguinal ligament, either CT venography or MR venography [4] can be used to supplement DU. Intravascular ultrasound is an additional imaging modality for determining the degree of iliac vein stenosis and is frequently used during iliac venous stenting procedures.

The duplex ultrasound should be done in an accredited vascular lab which has the appropriate equipment and personnel, as well as the standardized diagnostic protocols [5] that have been validated. In some states, an accredited vascular lab is required for insurance authorization and payment for both the DU and reimbursement for any subsequent venous procedure.

There are several manufacturers of ultrasound machines (Fig. 46.2) that can provide the information required to treat chronic venous insufficiency. The initial diagnostic DU should be done with more sophisticated equipment in a vascular lab, rather than handheld ultrasound equipment in an exam room, where the study is difficult to document and subject to examiner bias. After the initial study, DU during the procedure can easily be accomplished with portable imaging devices, as long as it has both good quality B-mode to facilitate vein access, tumescence, and distance measurements, as well as color flow imaging for rapid identification of superficial and deep veins.

For patients with visible truncal veins alone, duplex ultrasound of the deep, superficial, and perforator veins must still be performed to evaluate the degree and extent of venous incompetence and to guide the management. DU should be performed with the patient in both a supine and upright or standing position, using color Doppler and pulsed-wave Doppler with a linear 7.5–10 MHz transducer to directly visualize flow directionality. Venous reflux is characterized by antegrade flow, followed by retrograde flow, in the same vein after deep muscle compression and a Valsalva maneuver.

The examination usually begins at the saphenofemoral junction region, where the common femoral vein is evaluated for reflux and obstruction, using a Valsalva maneuver. Deep venous reflux is indicated by visualization of incompetent valve leaflets during compression and Valsalva maneuver, as well as blood flow in both directions in the same vein during compression and Valsalva maneuvers. If proximal iliac vein or vena cava obstruction is the cause of leg pain or swelling, the common femoral vein will often lose its normal respiratory cycling, and with fluid overload as the cause of leg swelling, deep venous signals often become pulsatile. In this same region, the saphenous vein at the saphenofemoral junction is also assessed for reflux, and, if reflux is present, the saphenous vein just below the junction is measured for size and extent of reflux. The great saphenous vein should then be assessed along its course for patency, diameter, and duration of reflux, as well as looking for any accessory or tributary veins, which should also be assessed for reflux and diameter. The popliteal fossa should then be evaluated, using a similar technique, for small saphenous vein assessment, with the patient in a prone position; all studies should also be done with the patient in the sitting or standing positions. After the truncal and deep veins have been evaluated at the saphenofemoral and sapheno-popliteal junction, the calf veins, including the posterior tibial and other perforator veins, should be evaluated for reflux. The tributary veins, which are often closer to the skin in the thigh, medial calf, and lateral calf and are frequently the reason for patients to seek evaluation, are also assessed for diameter and reflux during the initial evaluation.

DU criteria for abnormal veins in patients with CVI are outlined in the SVS-AVF guidelines for treating lower extremity venous disease [6]. They include:

The relationship between saphenofemoral and sapheno-popliteal junction; the diameter of each vein proximally, distally, and throughout its course; as well as the relationship of the truncal veins to the saphenous fascia and the presence of superficial venous duplication, accessory veins, and the location of tributaries and perforator veins are important to document for both procedural planning and insurance authorization. Although patients with CEAP 2 venous disease and no history of DVT rarely have deep venous disease or chronic changes of DVT, the deep system should always be evaluated in the common femoral vein location and popliteal vein location, so that postoperative studies, if the patient has pain or swelling and symptoms suggestive of DVT, can be compared to baseline studies of the deep venous system.

When completed, the duplex ultrasound report should document the extent of venous disease and be available for both insurance authorization and the procedure; it should include the following information:

The key to successful periprocedural venous imaging is having the correct ultrasound equipment and examination table. Periprocedural ultrasound is best performed using a tilt table, which allows the examination to be performed in the supine, prone, and reversed Trendelenburg position, as well as treatment in Trendelenburg position. In addition, having a procedural table that allows the surgeon to raise the patient’s head during the procedure is important for comfort, particularly with older patients (Fig. 46.3).

Although many ultrasound devices can be used for the procedure, a relatively inexpensive, portable ultrasound with good imaging resolution and mobility, as well as color, is the optimal system, particularly in an office-based setting, where room size may be limited.

With a foot pedal and sterile-covered ultrasound transducer, it should be possible for the operating surgeon to perform both the imaging and the procedure, with an aide or circulating nurse in the room to open sterile supplies, as well as adjusting the dials on the equipment and turning on the generator or laser when the venous procedure is performed. The assistant must know sterile technique to maintain a sterile environment while performing the duplex ultrasound procedure.