Endovascular revascularization is an effective procedure in treatment of chronic critical limb ischemia. The less invasive procedure in high risk patients produce the benefit to the patients. However, some of the patients cannot tolerate local anaesthesia. These patients need sedation or even general anaesthesia, which increase unnecessary risk to the patients. This study is conducted to evaluate the benefit of popliteal sciatic nerve block or popliteal block compare to sedation in critical limb patients undergoing angioplasty.

Inclusion Criteria:

• Age more than 20 year-old with chronic ischemic limb pain
• Scheduled for peripheral angioplasty under monitor anaesthesia care
• Expected timing of procedure not more than 3 hours

Exclusion Criteria:

• Age less than 21
• Cannot cooperate with the staff
• Having pain in other areas or both legs
• Contraindicate for nerve block
• Allergy to local anesthetic drugs or sedative drugs