Vein
Luminal area (mm2)
Diameter (mm)
CFV
125
12
EIV
150
14
CIV
200
16
Treatment
Endovascular Intervention
Reconstruction of the obstructed femoro-ilio-caval segment is done by using an endovascular approach. Open approach is reserved for patients who are not candidates for or who have failed an endovascular approach. The procedure is performed under general anesthesia given the frequent severe intraoperative pain/discomfort associated with balloon angioplasty. Access to the mid-thigh femoral vein is attained under ultrasound guidance. This allows angioplasty/stenting of the common femoral vein if needed without being impeded by the sheath. A 0.035 Glidewire (Terumo Medical Corp, Somerset, NJ) is passed into the inferior vena cava and a short (10 cm) 11 Fr sheath is placed. An ascending venogram is performed, renal function permitting, of the iliofemoral segments and inferior vena cava. Intravascular ultrasound (IVUS) [Volcano, San Diego, CA] is then performed using the 0.035″/7 Fr catheter and planimetric measurements of the luminal areas of the common femoral vein (CFV) , external iliac vein (EIV) , and common iliac vein (CIV) made. Normal luminal areas of 125, 150, and 200 mm2 are used as cutoffs in the CFV, EIV, and CIV, respectively. Any decrease in luminal areas below these reference values in a symptomatic patient is considered abnormal meriting angioplasty and stenting. A threshold value of 70% stenosis for correction, often used in arterial stenosis, does not apply because there is no correlation to venous pressure with grade of stenosis. Even minor stenosis of 30–40% can significantly elevate venous pressure in postthrombotic limbs. Venous hypertension is the basis of chronic venous disease; the aim of venous stenting is to relieve the venous hypertension. Predilation of the stenosis is performed using an 18 × 60 mm Atlas angioplasty balloon (Bard Peripheral Vascular, Tempe, AZ). Stenting is then carried out using 18–20 mm Wallstents (Boston Scientific, Marlborough, MA) with landing zones determined by IVUS and defined bony landmarks. The proximal landing zone is typically 1–2 cm above the iliac confluence that can be related to the corresponding vertebral body (upper, middle, or lower border). The distal landing zone is an area of adequate inflow in the CFV and can be related to a body landmark of the pubic ramus, femoral head, or lesser trochanter. Careful attention must be paid to the vein at the level of the inguinal ligament since this is often an area of compression. Stenting across the inguinal ligament must be performed in these cases and can be done with good results (Fig. 37.1) [1]. Given the decreased radial strength of the Wallstent, a Gianturco stent (Cook Medical, Bloomington, Indiana) is used to provide additional strength across the confluence with an extension of the Gianturco stent beyond the Wallstent proximally into the inferior vena cava (IVC). The Gianturco stent should be oversized relative to the Wallstent with an overlap of the lower half of the Z stent within the Wallstent to prevent stent embolization. An overlap of 3 cm or so between each Wallstent in the stack is required to compensate for foreshortening during post-dilation. Post-dilation is performed using the 18 × 60 mm angioplasty balloon. Completion IVUS is performed to ensure adequacy of luminal area. Any residual narrowing on IVUS interrogation is overcome by repeat dilation using a larger caliber angioplasty balloon taking into account the rated stent size deployed. Completion venogram is then performed. The 11 Fr sheath is subsequently withdrawn to just outside the vein, and a Surgicel Fibrillar patch (Ethicon, Somerville, NJ) is introduced via the sheath to aid in local hemostasis. Manual pressure is held to compliment the hemostatic effect. Kurklinsky et al. reported the Mayo Clinic group’s experience with stenting 91 postthrombotic iliac or iliofemoral veins . Primary, primary-assisted, and secondary patencies at 3 years were 71%, 90%, and 95%, respectively [2]. A recently published systematic review of deep venous stenting for CVD supported consideration of stenting as a treatment option given promising results and safety profile [3]. Graaf et al. reported their experience with stenting across the ilio-caval confluence and noted primary, primary-assisted, and secondary patency of 70, 73, and 78% at 36 months for self-expanding stents and 100% short-term (~5 months) patency for balloon expandable stents [4]. The largest published single institutional experience of 982 stents for chronic nonmalignant obstructive lesions of the ilio-caval-femoral vein segments with 6-year follow-up demonstrated a primary, primary-assisted, and secondary patency rates of 79, 100, and 100% for non-thrombotic lesions and 57, 80, and 86% for postthrombotic lesions, respectively. Risk factors for restenosis/stent occlusion after venous stenting were the presence and severity of postthrombotic disease [5].
Fig. 37.1
Stenting across the inguinal ligament
Chronic Total Occlusion (CTO)
Recanalization of CTOs is most commonly done through the use of a 0.035″ Glidecath (Terumo Medical Corp, Somerset, NJ) and 0.035″ Glidewire. A mid-thigh femoral vein approach is satisfactory in most instances with a short entry to lesion length allowing greater pushability. Right internal jugular vein approach is sometimes necessary when the antegrade approach fails. A body floss technique may be occasionally necessary as described by Kolbel and colleagues [6]. Other devices used for recanalization of CTO lesions include Quick-Cross support catheter (Spectranetics Corp, Colorado Springs, CO) and the TriForce Peripheral Crossing Set (Cook Medical, Bloomington, IN). Generally, a single-step dilation of the wire tract to the desired final size is safe and saves supplies. Serial angioplasty with sequentially larger balloons may have to be performed in some cases to create an appropriate recanalization tract. Rupture/hemorrhage from this maneuver is extremely rare. Angioplasty is carried out caudal to cranial (femoral access) or cranial to caudal (jugular access) as this enables easier retrieval of the angioplasty balloon if it disrupts . The likelihood of the latter happening is higher in CTO than in stenotic lesions. Use of stents, post-dilation, IVUS interrogation, and venogram are all performed as previously described. Raju et al. described their experience in 120 patients with chronic obstruction of the IVC and reported cumulative stent patency at 2 years of 82%. With regard to symptom relief, the group noted relief of pain and swelling of 74% and 51%, respectively, at 42-month follow-up. Additionally, the cumulative rate of complete ulcer healing at 2 years was 63% [7]. Fatima et al. reported 90% 2-year patency rate and 80% symptom-free survival in a series of 28 patients undergoing IVC stenting for occlusion/high-grade stenosis. Freedom from reintervention in this group , which included 13 patients with IVC filters at the 24-month mark, was 84% [8].
Stenting Across Inferior Vena Cava Filters
IVC filters can over time serve as a nidus for a fibrotic reaction that leads to IVC stenosis/occlusion. Trapped embolus may start the process in some instances. The occluded filter and IVC segment have to be recanalized to provide adequate outflow. This can be accomplished by removal of the filter if possible (usually not in chronic occlusions) or crushing the filter and stenting across it. A 24 mm Wallstent is typically used in the IVC/across IVC filters and has had good results (Fig. 37.2). Patients should be counseled about loss of filter protection for pulmonary embolism consequent to such procedures. In a review of 121 limbs that underwent stenting for postthrombotic ilio-caval occlusions, limbs stented for recanalized occlusions with (n = 23) and without IVC filters (n = 92) showing no difference in patency rates. Cumulative primary and secondary patency rates were 30% and 35% (p = 0.9678) and 71% and 73% (p = 0.9319), respectively. The primary factor, the authors conclude, affecting stent patency in such patients was severity of postthrombotic disease and not presence of a filter [9].
