Stent implantation is the common treatment method for iliac vein (IV) occlusion. IV stents usually enter into the inferior vena cava (IVC) to partially or completely cover the contralateral IV, but it is still uncertain whether this can increase the risk of thrombosis in the contralateral IV. The purpose of this study was to investigate the effect of the stent position on the bilateral IVs patency. A total of 261 patients with symptomatic IV lesions, including 177 patients with non-thrombotic iliac vein lesions (NIVLs) and 84 patients with thrombotic iliac vein lesions (TIVLs), were implanted with IV stents between July 2007 and June 2017. The data of these patients were retrospectively studied. The follow-up time was 6-114 months, and the median time was 62 months. A total of 183 cases had stenting into the IVC for more than 5 mm. The incidence of thrombosis in the contralateral IV was only 0.55% (1/183). A total of 17 short- and long-term cumulative cases had ipsilateral thrombosis on the stent side. There was no significant difference between the incidence of patients (8.79%, 7/78) with stenting into the IVC for less than 5 mm and those with more than 5 mm (5.46%, 10/183, P = 0.287). However, in the TIVLs group, the incidence of ipsilateral thrombosis between stenting positions less than 5 mm (29.6%, 8/27) and those more than 5 mm (8.77%, 5/57) was significantly different (P = 0.022). Stent implantation for NIVLs had an excellent long-term patency rate; the primary patency rate and the assisted primary patency rate were 97.7% and 100%, respectively. The entry of IV stents into the IVC was safe and had a very low incidence of thrombosis in the contralateral vein. Stenting less into the IVC increased the incidence of thrombosis in the ipsilateral vein, especially among thrombotic cases. Treatment of NIVLs using stent implantation had a better long-term patency rate. This principle plays an important guiding role in the endovascular therapy of IV lesions.
Keywords: Contralateral vein; Endovascular therapy; Iliac vein stenting; Thrombosis.