The non-invasive CT-scan 64-slice angiogram provides a complete anatomy of the coronary areteries as well as the respiratory system (lungs, etc.). This test is especially recommended for someone who has a family history as it views any sodft plaque that may build up between the inner layer and outer layer of the vessel. Soft plaque is high risk for heart attack as the soft plaque may rupture through the inner layer causing a blood clot that can cause a heart attack or stroke.
A cath angiogram only views the lumen (artery channel) for hard plaque that causes ischemia (lack of blood flow) to heart cells. Ischemia will cause chest pain or discomfort and can be relieved with a nitrate. According to your post pain is controlled by medication. That would indicate the medication dilates the coronary arteries, and that provides more blood to the deficit area. However, your stress test was negative, and that is not consistant with heart pains that is relieved by nitrates....a person can have silent ischemia which means there is no pain associated with aschemia, and a person can have a silent heart attack (damaged heart cells).
Because there is a family history of heart problems, your doctor may agree to CT scan angiogram to serve as a reference point for future observations as well as your current
The only test that is the most certain except for open heart surgery is the angiogram. The angiogram will give a very good indication as to what is going on. You are female so your hormones should protect you against heart disease or at least help protect you. When you go through menopause, the LDL levels will rise quickly. Usually, that it when the problems begin for women. I would think with the cholesterol medication you could get your LDL under control. Your LDL should be down to 100. Watch what you eat and limit or eliminated red meat if you can. If you do get severe chest pains, call your doctor because this is an indication that the arteries are spasming due to cholesterol blockage. If you become short of breath that would be an indication that something is going on with your heart valves. Check your blood pressure and make sure it stays within normal limits about 120/70. I think with medication you can manage your symptoms. Just to aware of the symptoms of blockage or valve problems.