The GORE® VIABAHN® FORTEGRA Venous Stent Post-Approval Study

Preoperative Inclusion Criteria: * Presence of lesion expected to necessitate treatment with the GORE® VIABAHN® FORTEGRA Venous Stent. * 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 themself. Intraoperative Inclusion Criteria: * Patient can accommodate an appropriately sized GORE® VIABAHN® FORTEGRA Venous 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 beyond the proximal and distal margins of the lesion. * Patient has adequate inflow/outflow to/from the target lesion(s), per investigator/sub- investigator discretion. * Lesion can be traversed with a guidewire. Intraoperative Exclusion Criteria: * Patient is contraindicated for treatment with the GORE® VIABAHN® FORTEGRA Venous Stent according to the IFU.