Fig. 19.1
(a) Localized block of iliac vein with good inflow and outflow. (b) Stenting in progress. (c) Post stenting appearance. Stent has to be oversized by 1.5 times
Post Stenting Complications
Neglen and his colleagues in a series of 982 consecutive patients of nonmalignant obstructive lesions of the iliac segment reported no mortality. The complications reported include [1]:
(a)
Access–related complications. Hematoma, injuries to femoral vein/femoral artery, retroperitoneal hematoma, etc., are reported. But these events can be minimized by USG-guided cannulation.
(b)
Early thrombotic events (less than 30 days). Neglen and colleagues reported an incidence of early thrombosis of 1.5 %.
(c)
Late thrombotic event. Twenty-three patients had ipsilateral thrombosis at a median of 13 months after stenting. Seven patients had late thrombosis of contralateral limb.
(d)
Stent migration. This is an unusual complication reported by Mullens and his team. They have reported migration of iliac vein stent for May-Thurner syndrome to the heart [10].
(e)
Stent infection. This is also an unusual complication reported by Dosluoglu et al. These complications were diagnosed by CT scan. One of the cases presented 6 months after insertion secondary to remote bacteremia. Both cases were treated surgically. A high index of suspicion is necessary to diagnose stent infection. Prophylactic antibiotics should be administered in high-risk situations [11].
(f)
Stent fracture. There are anecdotal reports of infrainguinal stent fractures. Such events are common with balloon-expandable stents [1].
Results of Iliac Vein Stenting
Stent Patency
The outcome depends on the nature of the pathology, whether thrombotic or nonthrombotic. The overall primary, assisted primary, and secondary cumulative patency rates reported by Neglen and team at 72 months were 79, 100, and 100 %, respectively, for nonthrombotic lesions. The outcome for thrombotic lesions was 57, 80, and 86 % [12]. Cumulative rate of in-stent stenosis (more than 50 %) at 72 months was 1 % for nonthrombotic and 10 % for thrombotic lesions [12]. Patency was much better in patients with NIVL than those with thrombotic disease [12]. Factors adversely affecting stent patency include young age, thrombotic lesions, long lesions requiring several stents, and higher degree of stenosis on IVUS [12]. The intervention side (left or right lower limb), gender of the patient, and thrombophilic state were not associated with increased stent block.
Clinical Outcome [12]
Pain and swelling. In Neglen’s series of patients, the rate of limbs with severe pain dropped from 54 to 11 % after the intervention. Gross swelling decreased from 44 to 18 %.
Ulcer healing. The authors reported a cumulative rate of ulcer healing at 5 years of 58 %. Eight patients had recurrence of ulcer.
Quality of life. There was significant improvement in QoL assessment.
Hemodynamic Outcome [12]
Improvement of the venous filling time, venous filling index, and venous volume was observed only after correction of superficial vein reflux also in addition to stenting. AVP and hand-foot pressure differential were shown to improve with stenting alone. When the obstructive component is relieved by stenting, the preexisting reflux is aggravated. This is because the obstructive pathology masked the intensity of reflux.
Iliac vein stenting alone significantly improved clinical outcome in a group of patients with combined obstruction and axial deep vein reflux, even though deep vein reflux was left untreated [13]. A subset of patients presenting with primary CVI with reflux pathology demonstrated presence of significant obstructive NIVL on IVUS evaluation. Iliac vein stenting has shown considerable improvement in this group even when the deep vein reflux is left uncorrected [14]. Neglen and colleagues in a subsequent report recommended elimination of superficial reflux along with stenting for a better outcome [12, 15].
Alerany and team in a report of endovenous treatment of iliofemoral chronic post-thrombotic obstruction in 41 limbs in 36 patients have reported successful outcome with no mortality or morbidity in 39 limbs (95 %) [16]. Nine limbs developed thrombotic events (23 %). At 33 months their primary, assisted primary, and secondary cumulative patency rates were 74, 87, and 89 %, respectively. The main risk factor for stent occlusion in this study was the severity of the thrombotic lesion. Thrombophlia, stent brand used, or extension into common femoral vein were not found to be increased risk factors for stent occlusion. The revised VCSS and Villalta scores showed significant improvement after stenting. It was also observed that the axial reflux in deep veins persisted in many patients; but this did not affect the clinical improvement [16].
Most of the workers have used stents designed for arterial tree. de Wolfe and group have reported their experience with the use of fully dedicated venous stents (sinus–Venous stents – OptiMed, Ettingen, Germany) [17]. They are longer and broader and have more flexibility and radial force. From March 2012 to July 2013, 48 patients with chronic iliofemoral obstructions (both thrombotic and nonthrombotic) were treated using this stent. At 3 months their cumulative primary, primary assisted, and secondary patency rates were 83, 84, and 97 %, respectively. They have reported no mortality, low morbidity, and no clinically relevant pulmonary embolism. The outcome was better for the nonthrombotic compared to the thrombotic group [17].
These data indicate that venous stenting can be performed with low morbidity and mortality and good long-term patency rate.
Open Surgical Reconstruction of Venous Obstruction
General Considerations
The primary and preferred treatment of venous occlusion of iliac segment is endovenous stenting. The relative safety and simplicity of endovenous stenting have favored this as the treatment option. Currently the indications for open surgery are very limited. The suggested indications for open surgical treatment include patients who are not suitable for endovascular repair and failed attempts at stenting [18]. The procedures can be performed in both thrombotic and nonthrombotic obstructions. It can also be undertaken in patients with iatrogenic or blunt trauma, postirradiation, and retroperitoneal fibrosis and those with benign or malignant tumors producing external compression [18].
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