Chronic venous insufficiency (CVI) affects millions of people throughout the United States. The higher venous pressure in the lower extremity veins of patients with CVI results in ambulatory venous hypertension. The majority of cases of CVI are due to past deep venous thrombosis of the iliofemoral segments.¹

CVI is a result of a combination of damaged valves leading to reflux and frank venous obstruction.2–6 Acute iliofemoral thrombosis is a common problem that is traditionally treated with conventional systemic anticoagulation (heparin followed by warfarin). Despite anticoagulation, chronic changes of the iliac vein with partial or complete obstruction will occur and lead to postthrombotic syndrome (PTS). During the process of chronic obstruction of the iliac vein, inflammatory changes take place and cause vein wall fibrosis that leads to valve dysfunction, reflux, and CVI.^7,8 PTS results in significant morbidity, decreased quality of life, and multiple visits to healthcare providers.⁹

The symptoms of CVI include ulcerations, chronic pain, and swelling.² Patients with CVI have traditionally been treated with conservative measures such as medical-grade compression stockings, intermittent compression devices, and wound care in patients with venous stasis ulcers.^10–14 Reestablishment of direct antegrade flow through the iliac venous system can alleviate much of the patient’s symptomatology by correcting the obstructive component of CVI.^15,16 The remaining reflux component may be addressed by valvular surgery (valvuloplasty, valve transplantation) or percutaneous valve insertion.^14,17,18

All patients should have their venous system imaged to determine the adequacy of inflow and outflow. These patients require an initial duplex ultrasound examination of the lower extremity veins to evaluate the patency of venous segments (tibial, popliteal, femoral, and common femoral veins). The pelvic veins and inferior vena cava (IVC) (outflow) are difficult to evaluate with ultrasound, so patients should also undergo either magnetic resonance or computed tomographic venography (MRV, CTV) of the pelvis and abdomen to determine the length of obstruction and adequacy of outflow. Definitive venography will be performed at the time of the intervention.3,9

Air plethysmography is a practical, noninvasive, and relatively inexpensive test that provides physiologic quantitative information about the lower leg (excluding the foot) regarding CVI and correlates with ambulatory venous pressure (AVP) measurements.19–21 The study is performed with an air chamber that surrounds the lower part of the leg and connects to a pressure transducer and recorder. A baseline reading is obtained with the patient in the supine position and the leg elevated to 45 degrees. The patient is then placed in the upright position with all weight on the contralateral limb until the veins are full of blood. This change is the functional venous volume. The venous filling index (VFI) can be calculated (90% venous volume divided by the time required for filling to 90% of venous volume). The patient then performs the heel-raise maneuver to displace the venous volume; the volume displaced by this maneuver is the ejection volume. The ejection fraction (EF) equals ejection volume divided by venous volume. Multiple (10) heel raises are then performed to reach a residual volume plateau. Residual volume divided by venous volume is the residual volume fraction (RVF). The VFI is a measure of global reflux, EF is a measure of calf muscle pumping function, and RVF is a reflection of AVP.⁹

Technique

Anatomy and Approach

Knowledge of the normal anatomy and variations of the venous system in the lower extremity, pelvis, and abdomen is required for a safe and successful intervention. A critical review of the preliminary venous studies (ultrasound, MRI, CT) is necessary to determine whether the patient is a candidate for percutaneous intervention, as well as for procedural planning itself (Fig. 100-1). In the popliteal fossa, the vein is often superficial (closer to the posterior skin surface) to the artery, making access more straightforward.¹³ Other veins that enter the popliteal vein can also be used for access, including the lesser saphenous vein, soleal vein, and veins draining the gastrocnemius muscle group.²²

Technical Aspects

Identification of Venous Access Site

Access to the venous system from the popliteal fossa is preferred. This approach allows easy antegrade venography and improved application of directional force to catheters and guidewires while traversing rigid occlusions. The patient is placed prone on the angiographic table. Ultrasound is used for a preliminary review of the venous anatomy of the popliteal fossa. Either the popliteal vein or, preferably, a more superficial vein that drains into the popliteal vein is identified and selected for access. It is preferable (when possible) to avoid direct puncture and subsequent injury to the popliteal vein itself. Access from a more superficial vein will also allow easier hemostasis after the procedure.

Venous Entry

Once identified, the access vein is punctured with a 21-gauge needle under direct ultrasound guidance. The popliteal artery is specifically identified so that it will not be in the course of needle access. Because the vein is collapsible, a brisk sharp thrust may be needed to enter the vein. A tourniquet may be used above the knee to facilitate venous distention. Once the tip of the needle is seen within the vein, insertion of a 0.018-inch guidewire can be performed at this time. If tip placement is uncertain, aspiration of blood and subsequent injection of contrast material may be required to identify an intraluminal position. After insertion of the 0.018-inch guidewire, the micropuncture sheath is inserted, followed by a standard 0.035-inch guidewire. A short 6F sheath is then placed and connected to a heparinized saline infusion via the side arm.

Preliminary Venography

Contrast venography of the popliteal, femoral, and common femoral segments is performed via the sheath (Fig. 100-2, A-C). If satisfactory, a 5F angled multipurpose catheter is advanced into the common femoral vein. Venography of the iliac segment is then performed (Fig. 100-2, D). Multiple oblique projections will often be required to identify the true course of the occluded iliac venous segment. Because multiple collateral channels will frequently be present, identification of the occluded venous channel is often challenging. Systemic anticoagulation is then initiated.