This is a prospective, multi-center, single-arm, non-blinded clinical trial designed to investigate the safety and efficacy of the Vesper DUO Venous Stent System as compared to a pre-defined performance goal (PG) established from published, peer reviewed scientific literature related to stenting of iliofemoral venous outflow obstructions.

Inclusion Criteria:

1. Males or non-pregnant, non-breastfeeding females ≥18 years of age at the time of consent

2. Subject is able and willing to provide written informed consent prior to receiving any non-standard of care, protocol specific procedures

3. Female subjects of childbearing potential must have a negative pregnancy test within 7 days prior to treatment and must use some form of contraception (abstinence is acceptable) throughout the time of clinical trial exit

4. Willing and capable of complying with all required follow-up visits

5. Estimated life expectancy ≥1 year

6. Subject is ambulatory (use of assistive walking device such as a cane or walker is acceptable)

7. Body mass index (BMI) <40

8. Clinically significant symptomatic venous outflow obstruction in one iliofemoral venous segment (one limb) per subject, is indicated for venoplasty and stenting, and meets at least one of the following clinical indicators:

   1. Clinical-Etiology-Anatomy-Pathophysiology (CEAP) score ≥3
   2. Venous Clinical Severity Score (VCSS) pain score ≥2
   3. Suspected deep vein thrombosis (DVT) with symptoms occurring prior to receiving a DUO Stent

9. Subject is willing and able to comply with PI recommendation for compression therapy, if required

10. Presence of unilateral, non-malignant venous obstruction of the common femoral vein (CFV), external iliac vein (EIV), common iliac vein (CIV), or any combination thereof, defined as a ≥50% reduction in target vessel lumen diameter and confirmed by venographic or IVUS imaging. The cranial point of the obstruction may extend to the iliac vein confluence of the inferior vena cava (IVC) and the caudal point may be 2mm above either the inflow of the deep femoral (or profunda) or the lesser trochanter, whichever is most cranial

11. Obstructive lesion(s) able to be treated with continuous stent coverage

12. Adequate inflow to the target lesion(s) involving at least a patent femoral or deep femoral vein and a landing zone in the CFV free from significant disease requiring treatment

13. Reference vessel diameter is of adequate size to accommodate the appropriate size stent as measured by IVUS

14. All vessels from insertion site through target vessel can accommodate a 9F or 10F sheath, depending on the stent size used

15. Ability to cross interventional devices through target lesion(s)

16. In DVT subjects, successful treatment of acute thrombus must have occurred prior to receiving any DUO Stents for an underlying obstructive lesion. Successful treatment of acute thrombus is defined as reestablishment of antegrade flow with ≤30% residual thrombus (confirmed by venogram or IVUS) and freedom from bleeding and symptomatic pulmonary embolism (confirmed by imaging). After successful treatment of thrombus is confirmed, eligible obstructive lesion(s) can be treated with a DUO Stent during the same procedure.

17. All subjects must undergo a SARS-CoV-2 test and have a negative test result within 8 days of the index procedure. If a SARS-CoV-2 test is unavailable due to institution policy, a test shortage, or if there is a delay in test results, the subject must complete the COVID-19 questionnaire and must have answered NO to all questions to be eligible for enrollment. A SARS-CoV-2 test will not be required for enrollment if a subject has received a complete cycle of an authorized COVID-19 vaccine or has documented evidence of a positive COVID-19 antibody test and is asymptomatic and has no long-lasting effects (per PI discretion) from a prior COVID-19 infection.

18. A measured temperature less than 99.5°F (37.5°C) on the day of the index procedure and no history of fever or feeling feverish within 14 days of the index procedure

19. No prior history, within 60 days of the index procedure, of a SARS-CoV-2 positive test, or COVID-19 symptoms

Exclusion Criteria:

1. Target limb symptoms caused by peripheral arterial disease
2. Presence of unresolved significant pulmonary embolism prior to use of the DUO Venous Stent System confirmed by chest CT. If subject has documented history of significant pulmonary embolism within the last 6 months, a chest CT is required to confirm significant pulmonary embolism is not currently present.
3. Presence of IVC obstruction or target venous obstruction that extends into the IVC
4. Presence of acute DVT located outside target limb
5. Contralateral venous occlusive disease of the CFV, EIV, and/or CIV, with planned treatment ≤390 days after the index procedure
6. Uncontrolled or active coagulopathy or known, uncorrectable bleeding diathesis
7. Coagulopathy causing INR >2 which is not amenable to medical treatment
8. Platelet count <50,000 cells/mm3 or >1,000,000 cells/mm3 and/or White blood cell (WBC) <3,000 cells/mm3 or >12,500 cells/mm3
9. Uncorrected hemoglobin of ≤9 g/dL
10. Subject is on dialysis or has an estimated glomerular filtration rate (eGFR) <30 mL/min. In subjects with diabetes mellitus, eGFR <45 mL/min.
11. History of Heparin Induced Thrombocytopenia
12. Presence of known aggressive clotting disorders such as Lupus Anticoagulant Disorder, Antiphospholipid antibody syndrome, homozygous gene Factor V Leiden or Prothrombin gene abnormalities, Protein C and S deficiency or Antithrombin deficiency
13. Known hypersensitivity or contraindication to antiplatelet therapy or anticoagulation, nickel, or titanium
14. Contrast agent allergy that cannot be managed adequately with pre-medication
15. Intended concurrent adjuvant procedure (except for venoplasty) such as creation of temporary arteriovenous fistula, femoral endovenectomy or saphenous vein ablation and/or saphenous vein stripping during the index procedure
16. Subjects who have had any prior surgical or endovascular procedures to the target vessel. Note that subjects who have had successful catheter-directed or mechanical thrombolysis in the target vessel for DVT at least 90 days prior to the index procedure may be included
17. Planned surgical or interventional procedures of the target limb (except thrombolysis and/or thrombectomy in preparation for the procedure or vena cava filter placement prior to stent implantation in subjects at high risk for pulmonary embolism) within 30 days prior to or 30 days after the index procedure
18. Planned surgical or interventional procedures for other medical conditions (i.e., not associated with the target limb) 30 days prior to or 30 days after the index procedure
19. Previous venous stenting of the target limb, the IVC, or contralateral limb if stents extend into the IVC
20. Iliofemoral venous segment unsuitable for treatment with available sizes of DUO Stent implants
21. Lesions with intended treatment lengths extending into the IVC
22. No safe landing zone at or above the profunda femoral confluence
23. Participating in another investigational study in which the subject has not completed the primary endpoint(s)
24. Has other comorbidities that, in the opinion of the Investigator, would preclude them from receiving this treatment and/or participating in study-required follow-up assessments