Venclose RF Ablation System for the Treatment of IPVs

Inclusion Criteria: * Patient is \>= 18 years. * IPVs to be treated have an outward flow duration of \>= 0.5 seconds immediately after release of manual distal compression with patient standing or in Reverse Trendelenburg. * IPV(s) to be treated have a diameter of ≥ 3.5 mm located caudal edge of ankle. * Has been diagnosed with refractory symptomatic disease attributable to the IPV to be treated. * Is able to ambulate. * Is able to comprehend and has signed the Informed Consent Form (ICF) to participate in the study. * Is willing and able to comply with the Clinical Investigation Plan and follow-up schedule. Exclusion Criteria: * Has venous insufficiency secondary to venous obstruction proximal to the intended treatment site. * Has thrombus in the vein segment to be treated. * Has untreated critical limb ischemia from peripheral arterial disease. * Is undergoing active anticoagulant therapy for Deep Vein Thrombosis or other conditions (e.g., warfarin, direct oral anticoagulant or low molecular weight heparin) or has a history of Deep Vein Thrombosis within the last 6 months or hypercoagulable state. * Patients with known bleeding or clotting disorders or unwilling or unable to frequently ambulate post-operatively. * Has had prior venous procedures in the study limb within the last 30 days (including thrombolysis, thrombectomy, stenting, ablation, phlebectomy, visual or foam sclerotherapy). * Has undergone or is expected to undergo any major surgery within 30 days prior to or following the study procedure. * Has a condition, judged by the treating physician, that may jeopardize the patient's well-being and/or confound the results or the soundness of the study. * Is pregnant or lactating at the time of the study procedure or is intending on becoming pregnant within 30 days following the study procedure. * Is participating in another clinical study that is contraindicated to the treatment or outcomes of this investigation