A rare case of femoral vein stenosisLifan Shao1, Naixia Wang2, Guangxin Cao21Master student,Weifang Medical University,Weifang City,Shandong,China 2610002Department of Vascular Surgery, Weifang People’s Hospital, No.151 Guangwen Street,Kuiwen District,Weifang City,Shandong,China26100011Lead Author:Lifan Shao; Master student, Weifang Medical University, Weifang City, Shandong, China, email: 1163786632@qq.com Correspondence should be addressed to Guangxin Cao; No.151 Guangwen Street, Kuiwen District, Weifang City, Shandong, China, email:caoguangxinvip1234@163.comThe patient provided written informed consent for the report of his case details and imaging studies. The authors have no competing interests.Abstract: A 61-year-old male patient with post-thrombotic syndrome came to our hospital for treatment. Imaging showed stenosis of the left iliac vein, and post-symptoms of iliac vein stenosis improved significantly after iliac vein stent implantation. A year later, the patient returned with a ruptured left foot, and imaging revealed stenosis of the left common femoral vein. This case has certain reference value for the study of complications after iliac vein stent implantation.Keyword: Chronic iliofemoral venous obstruction; Iliac vein stenting; Post-thrombotic syndromeCase report: A 61-year-old male. Over 20 years ago, there was no obvious cause of local pigmentation of his left inner leg, which was mild at the beginning and gradually aggravated. The pigmentation area gradually expanded with local ulcers accompanied by leg swelling and discomfort. He was previously treated in another hospital, and his ulcer healed after conservative treatments. Four months ago, the patient was injured by heavy objects falling on his left leg that caused local ulcers. He came to our hospital in April 2022 and was diagnosed with varicose veins of the lower limb accompanied by ulcers and infection of the skin tissue of the lower limb. Anterograde deep vein angiography of the lower limb was performed in our hospital. Imaging revealed stenosis of the left iliac vein and sequelae of thrombosis in the right superficial femoral vein. Balloon dilation of the left superficial femoral vein + iliac vein stent implantation was performed. Intraoperative angiography showed that the left common iliac vein stenosis(IVS) was greater than 70%, and the common femoral vein was well developed without significant stenosis (FIG. A). Through left popliteal vein puncture, WALLSTENT (16 mm*90 mm) was placed through a guide wire. and the left superficial femoral vein balloon was dilated. The stent position was satisfactory after surgery. IVS was significantly relieved, blood flow was restored, and no significant abnormality was observed in the common femoral vein (FIG. B). The ulcer healed gradually after the operation. In August 2023, the patient returned to our hospital due to non-healing of his left foot. Anterograde imaging of the deep vein of the lower limb was performed. Imaging showed that the length of the stent was slightly shortened, the patient’s left iliac vein was well developed, and the left common femoral vein was obviously narrow at the lower end of the stent (FIG. C). Left iliofemoral venography + stent implantation was performed. Through left popliteal vein puncture, WALLSTENT (14 mm*90 mm, 12 mm*90 mm) was implanted through a guide wire, Post-operative angiography showed satisfactory stent position, good shape, disappearance of stenosis, and satisfactory blood flow velocity (FIG. D).Discussion:IVS is clinically considered the anatomic basis of the deep vein thrombosis of the lower limbs and the cause of post-thrombotic syndrome(PTS) in most patients[1]. IVS is very common in clinical practice, with an incidence as high as 22%–50%[2]. In recent years, with the improvement of diagnostic technology, the incidence of IVS has gradually increased. IVS is mostly related to the dissected structure around the common iliac vein, and the left iliac vein is mostly narrowed by the compression of the right iliac artery and the fifth lumbar vertebrae. The incidence of left side deep vein thrombosis (DVT) is significantly higher than that of right side DVT. IVS can affect blood flow and cause deep vein thrombosis DVT of the lower extremities, which may increase the mortality of patients[3]. After stent implantation for IVS, displacement and blockage may occur, and the stenosis of the lesion site is often recurrent. However, one year after the common iliac vein stent implantation, common femoral vein stenosis occurrs below the stent, which is a rare complicationthat has been documented in only a few reports at home and abroad.After consulting relevant data and discussion, the reasons for the formation of common femoral vein stenosis after stent implantation in this case are speculated as follows. The common femoral vein is also oppressed by the hip joint and its surrounding muscles, ligaments and other tissues. Chen previously reported a case of deep vein thrombosis caused by femoral vein compression by the medial femoral muscle[5]. Relevant studies showed that WALLSTENT venous stenting in the treatment of post-iliofemoral thrombosis or compression obstruction is safe and effective with a good primary and secondary patency rates of 87% and 95% at 72 months[5], However some shortcomings are worth mentioning. For example, the radial force at the end of the stent is small and the stent is significantly shortened after implantation[5], as reflected in angiography (FIG. C). In addition, due to the small radial force at the end of the stent, the uneven support force inside the lumen may also lead to the common femoral vein stenosis.The pressure and wear caused by the surrounding tissues also generate internal shear stress, which causes irreversible damage to the tube wall and promotes the occurrence of inflammatory reaction, thus further affecting the normal function of the tube wall elastin, resulting in the thinning of the wall of the common femoral vein, reducing its resistance to pressure from the surrounding tissues, and eventually leading to stenosis.Reference:[1]S. Vedantham, et al., Quality improvement guidelines for the treatment of lower-extremity deep vein thrombosis with use of endovascular thrombus removal, Vasc. Intervent. Radiol. 25 (9) (2014) 1317–1325.[2]Kutsenko O, McColgan Y, Salazar G. Iliac Vein Stenosis: Is the Data Strong Enough for Stenting in the Young Pelvic Venous Disorders (PeVD) Population? Tech Vasc Interv Radiol. 2021 Mar;24(1):100733. doi: 10.1016/j.tvir.2021.100733. Epub 2021 Apr 15. PMID: 34147201.[3]Wang H, Jia W, Xi Y, Li Y, Fan Y, Deng X, Chen Z. Morphometric and Hemodynamic Analysis of the Compressed Iliac Vein. J Endovasc Ther. 2022 Nov 20:15266028221134895. doi: 10.1177/15266028221134895. Epub ahead of print. PMID: 36408873.[4]Chen YT. The Medial and Posterior Compression of the Distal Femoral Vein: An Underused Approach to Detect Venous Thrombosis. J Coll Physicians Surg Pak. 2021 Nov;31(11):1389-1390. doi: 10.29271/jcpsp.2021.11.1389. PMID: 34689511.[5]Gagne PJ, Gagne N, Kucher T, Thompson M, Bentley D. Long-term clinical outcomes and technical factors with the Wallstent for treatment of chronic iliofemoral venous obstruction. J Vasc Surg Venous Lymphat Disord. 2019 Jan;7(1):45-55. doi: 10.1016/j.jvsv.2018.07.016. Epub 2018 Oct 24. PMID: 30558730.