Clinical study on the different lengths of inferior vena cava stent implantation for non-thrombotic iliac vein lesions

Objective To assess the safety and influence of the stents extended into inferior vena cava in patients with non-thrombotic iliac vein lesions (NIVLs) on the bilateral iliac vein blood flow. Methods We retrospectively reviewed data from July 2008 to June 2017 in 197 patients with NIVLs who underwent iliac vein stenting and complete follow-up was obtained at our institution.Of these patients, stents extended into IVC more than 10 mm in 141 cases, less than 5 mm in 22 cases, and 34 cases were between 5 and 10 mm.Restenosis and thrombosis of bilateral iliac vein and patency of these stents were assessed in the follow-up.The count data were expressed by percentage (%), and the sample comparison rate was analyzed by Fisher exact test formula.The measurement data were first tested for normal distribution and homogeneity of variance, and then corrected t test. Results The two hundred and five iliac vein stents were placed in 197 patients. During a mean follow-up of 58.7 months (6 to 98 months), there were no thrombosis occurred in the contralateral iliac vein, 6 patients suffered restenosis or new thrombosis in the stents, the incidence between stenting positions less than 5 mm (13.6%, 3/22) and those more than 5 mm (3.43%, 6/175) was sighificantly different (P<0.001), and 5 of 6 patients had a good patency after endovascular therapy. During the fllow-up, the primary and assisted-primary patency rates were 97.0% and 99.5%. Conclusions From these data, it appears that there is a very high patency rates of the stenting treatment for the NIVLs, and it is safe for the stents extended into the IVC, stenting across the iliocaval confluence can result in a small number of new contralateral thromboses. Moreover, the risk of stents restenosis or occlusion is high when stents are not extended into IVC. Key words: Iliac vein; Stent; Vein thrombosis; Interventional therapy