Clinical Outcomes of IVUS-guided Stenting Using the Boston Scientific Vici® Venous Stent System in Treating Patients With Chronic Non-malignant Iliofemoral Vein Obstruction

Key Inclusion Criteria: 1. Ethnic Chinese subjects of age ≥ 18 years (or meet age requirements per local law) 2. Subjects willing to provide written informed consent prior to the study and AND willing to comply with all follow-up evaluations at the specified times 3. Subjects with presence of unilateral, clinically significant, chronic non-malignant obstruction of the common femoral vein, external iliac vein, common iliac vein, or any combination thereof, defined as a \> 50% reduction in target vessel lumen diameter measured by venogram and/or IVUS during procedure 4. Clinically significant venous obstruction defined as meeting at least one of the following clinical indicators: * Clinical severity class of CEAP classification ≥ 3 * rVCSS Pain Score ≥ 2 5. Negative pregnancy test in female subjects of potential child-bearing 6. Intention to stent the target lesion only with the Vici Stent(s) Key Exclusion Criteria: Pre-Procedural EC-- 1. Subjects with presence or history of clinically significant pulmonary emboli within 6 months prior to enrollment. 2. Subjects with venous obstruction that extends into the inferior vena cava 3. Subjects with contralateral disease of the common femoral vein, external iliac vein, common iliac vein, or any combination thereof with planned treatment within 30 days after enrollment 4. Subjects with a life expectancy \< 12 months 5. Female of childbearing potential who is pregnant or plans to become pregnant during the duration of the clinical study (Note: subjects who plan to become pregnant after 12-month follow-up visit may be included in the trial at the discretion of treating physician) 6. A. Subjects with uncontrolled or active coagulopathy OR B. Subjects with known uncorrectable bleeding diathesis with the following definitions: * Uncorrected INR ≥ 2.0 or aPTT ≥ 1.5X normal local lab value * Platelet count \< 80,000 7. Subjects with uncorrected hemoglobin of ≤ 9 g/dL 8. Subjects with an estimated glomerular filtration rate (eGFR) \< 30 mL/min. In patients with diabetes mellitus, eGFR \< 45 mL/min. 9. Subjects have known hypersensitivity to nickel or titanium 10. Subjects have contrast agent allergy that cannot be managed adequately with pre-medication 11. Subjects will have intended concurrent thrombolysis or thrombectomy procedure OR intended or planned (within 30 days) adjuvant procedure such as creation of temporary AV fistula, placement of IVC filter, endovenectomy or saphenous vein ablation 12. Subjects currently participating in another drug or device clinical trial (participation in observational studies is acceptable) 13. Subjects judged to be a poor candidate by the primary investigator 14. Subjects who have had any prior surgical or endovascular intervention of the target vessel Intra-Procedural: 1. Subjects in whom the lesions cannot be traversed with a guide wire 2. Subjects where the obstruction extends into the inferior vena cava or below the level of the lesser trochanter 3. Subjects whose vein diameters are not within limits stated in the Instructions for Use of study device as determined by venogram and/or IVUS 4. Subjects who do not meet the venogram or IVUS binary stenosis by the definition above (IC3), as determined by the treating physician 5. Subjects who are judged by treating physician to have a lesion that prevents completed inflation of a balloon dilation catheter or proper placement of the stent or the stent delivery system