RecruitingProcedureRoad Mapping Guided Puncture Versus Ultrasound Guided Puncture During Retrograde Angioplasty Feasibility and SafetyThe study aims to compare the technical feasibility and safety of road mapping-guided versus ultrasound-guided retrograde arterial puncture in patients with (CLTI) as measured by: * Puncture success rate * Access-related complication rate (e.g., hematoma, vessel dissection, perforation)