Conversation: The conversation between human and AI assistant.
[|Human|] Hi,my father is of age 56. He is diabetic from last 9 years. An year before he had heart attack and have undergone heart by pass surgery. Now his TMT test is positive. His cholesterol is under control. Is there anything to worry? What should we do next?
[|AI|]  Hello and thank you for using Chat Doctor. I understand your concerns. I can make a lot of assumptions based on the brief history you provided. However, I will try to explain some common scenarios. Maybe an artery that was not significant by diameter was left without by-pass, judged by the cardiac surgeon. This same artery could have had a significant narrowing that could produce a positive cardiac stress test. There is also a chance of narrowing of one of the by-pass vessels, keeping in mind that the rate of narrowing, especially when saphenous vein is used for by-pass, is 8-10%. Having a positive stress test, I would recommend a coronary angiogram, to check the native arteries, as well as the patency of the by-pass grafts. I hope I was helpful. Take care.