Investigation of Femoropopliteal In Situ Valve Formation With the InterVene System

Inclusion Criteria: * Symptomatic CVI subjects, Clinical Etiological Anatomical Pathophysiological (CEAP) grade 3 to 6; * Failed compression therapy of at least 6 months' duration; * Deep system venous reflux characterized by \>1 second reflux time; * Presence of at least one target site within the target vessel. Exclusion Criteria: * Untreated significant superficial venous incompetence which, in the opinion of the Investigator, may be the primary source of existing symptoms; * Deep venous intervention in the target limb or outflow vessels within 6 months of consent; * Significant peripheral arterial disease with an ankle-brachial index of \<0.50 or with incompressible vessels; * Acute deep venous thrombosis (DVT) within 3 months of consent; * History of stroke within the last 6 months; * Flow-limiting venous outflow obstruction central to the intended target sites; * Insufficient inflow through the treatment vein upon manual augmentation; * Chronic, diffuse, post-thrombotic femoropopliteal vein disease that, in the Investigator's opinion, would preclude venous valve formation or would inhibit flow through the treatment sites; * Chronic renal insufficiency with creatinine level of ≥2mg/dL; * Hemoglobin level \<9.0 mg/dL; * Platelet count \<50,000 or \>1,000,000 per mm3; * Total white blood cell count \<3,000/mm3; * Pregnant or lactating female; positive pregnancy test, women of childbearing potential must be tested; * Non-ambulatory patients;