This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vascular surgery, Subject name: Surgery
[{'content': 'A patient with critical lower limb ischemia presents with \nSelect and explain. \nA. Intermittent claudication, B. Intermittent claudication and gangrene, C. Rest pain and ischemic ulcers, D. Intermittent claudication and ischemic ulcers', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Critical lower limb Ischemia is characterized by rest pain. Ulcers and gangrene may occur in patients with critical limb ischemia Critical limb ischemia CLI results from severe aerial occlusive disease in whom resting blood flow cannoy provide fro basal nutrition needs of tissues Ischemic symptoms are present even during rest (rest pain) Pain is worse when legs are horizontal and may improve when legs are kept in a dependent position Ischemic ulcers, lesions on the foot and gangrene may be seen ABI <0.5 Ref: Sabiston 20th edition Pgno :1784', 'role': 'assistant'}]