This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Which of the following represents the clinical presentation of a patient with critical lower limb ischemia? \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: Patient with critical limb ischemia has insufficient perfusion to sustain limb at rest, if left untreated such patients require amputation in 6 months. They experience pain at rest, ulcers and ischemic gangrene. Rest pain is exacerbated when lying supine and is improved by dangling the feet. Narcotics can also relieve the pain. Ref: Noninvasive Cardiovascular Imaging: A Multimodality Approach By Mario J. Garcia, Page 123; Schwaz's Principles of Surgery, 9th Edition, Chapter 23", 'role': 'assistant'}]