Ecraprost in lipid emulsion is being developed for the treatment of Critical leg ischemia (CLI), which is the most severe form of peripheral arterial disease (PAD); This trial is designed to assess the efficacy and safety of the drug in the treatment of CLI.

Inclusion Criteria:

• Critical leg ischemia (CLI) defined as distal extremity pain at rest, or peripheral ischemic ulcer(s), with severe hemodynamic impairment as diagnosed by ankle systolic pressure, toe systolic pressure or TcPO2
• Subjects will already be scheduled to receive a revascularization procedure (e.g., by-pass graft, endovascular procedure, etc.) involving a distal target artery below the knee joint (e.g., below the knee joint popliteal, anterior/posterior tibial, peroneal, plantar, pedal, etc.) as part of their normal standard of care.

Exclusion Criteria:

• Subjects with a previous major amputation (at or above ankle)
• Subjects with end stage renal disease (ESRD) defined as significant renal dysfunction evidenced by estimated creatinine clearance of < 20 cc/min, or receiving chronic hemodialysis therapy.