The 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)

Inclusion criteria: -.

1. Adults : Both male and female participants.

2. Diagnosed with critical limp threatening ischemia (CLTI):

   significant occlusions in the femoropopliteal

   o Rutherford Class 5: Non-healing wounds or ulcers

3. Failed or unable to achieve antegrade access:

   Patients requiring retrograde puncture for the procedure.

4. Planned intervention with retrograde access: Candidates for endovascular interventions, including angioplasty, stent deployment

Exclusion criteria:

• Active infection at the puncture site: Any localized infection, particularly over the ankle region , will be an exclusion.

• Severe calcification or anatomical abnormalities: Patients with excessive arterial calcification or significant anatomical distortion preventing safe retrograde puncture.