• Patient is at least 18 years of age.

• Patient is willing and able to comply with all follow-up evaluations as well as any required medication or compression regimen.

• Patient is able to provide informed consent.

• One of the following: Clinical severity class of CEAP 'C' classification ≥3 or rVCSS pain score ≥2.

• Intention to treat the target areas with only the GORE® VIAFORT Vascular Stent.

• Estimated life expectancy ≥1 year.

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

• Patient has adequate inflow to the target lesion(s), per investigator/sub-investigator discretion, involving at least a patent femoral or deep femoral vein.

• Presence of non-malignant symptomatic unilateral iliofemoral venous obstruction.

• Presence of non-malignant unilateral obstruction of the common femoral vein, external iliac vein, and/or common iliac vein defined as occlusion or at least 50% reduction in target vessel lumen as measured by procedural IVUS and venogram.

• Patient can accommodate an appropriately sized GORE® VIAFORT Vascular Stent as per reference vessel diameter (see IFU), as determined by intraoperative IVUS post pre-dilation.

• Patient must have appropriate access vessels to accommodate the delivery sheath for the selected device size.

• Patient has adequate landing zones free from significant disease requiring treatment within the native vessels beyond the proximal and distal margins of the lesion.

• Patient has adequate inflow to the target lesion(s), per investigator/sub-investigator discretion, involving at least a patent femoral or deep femoral vein.

• Lesion can be traversed with a guidewire.

• Disease involves only unilateral iliofemoral venous segments with intent to stent all affected iliofemoral segments. Patients with disease extending into the inferior vena cava or contra-lateral iliofemoral veins who are anticipated to require endovascular or surgical treatment within 12 months after investigational device implant will be excluded.

• Patient does not have significant (i.e., \>20% residual thrombosis) acute thrombus within the target stent area at the time of investigational device placement. Patients with acute thrombus within the target stent area must have thrombus successfully treated prior to investigational device placement. Successful thrombus treatment is defined as reestablishment of antegrade flow with ≤20% residual thrombosis as confirmed by IVUS and venogram, AND freedom from bleeding, vascular injury, or hemodynamically significant pulmonary embolism. After successful thrombus treatment, investigational device placement can occur within the same procedure.