Approximately 30 patients will be enrolled in this 12-week study designed to assess the effect of continuous subcutaneous Remodulin therapy on the outcome of infrainguinal bypass grafts in patients with critical limb ischemia (CLI). Portions of the study will be conducted in the hospital and on an out-patient basis. The study will be conducted at multiple centers.

• Patients with critical limb ischemia and an appropriate reference lower-limb ischemic wound due to documented peripheral arterial disease who have had an autogenous vein infrainguinal bypass graft performed immediately prior to study initiation.