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: Unknown
[{'content': 'False elevation of ABPI is seen in: \nSelect and explain. \nA. DVT, B. Acute limb ischemia, C. Chronic Venous insufficiency, D. Calcified vessel walls', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ref. Sabiston Textbook of Surgery. Pg. 497\n\xa0\nThe ankle-brachial pressure index (ABPI) is the ratio of systolic pressure at the ankle to that in the arm .\nThe higher of the pressures in the dorsalis pedis and the posterior tibial arteries serves as the numerator ,with the higher systolic pressures between the brachialis serving as the denominator .\n\nResting ABPI is normally about 1 ,\n<0.9 indicated some degree of arterial obstruction\n<0.3 suggests imminent necrosis\n\n# Artefacts are due especially due to calcified arteries, which are often incompressible and lead to a falsely high pressure or ABPI result ,especially in diabetics.', 'role': 'assistant'}]