The reason is that it is the small, young and volatile plaque that causes heart attacks.
This study recommends Cardio CT or MRI to detect the extent of disease. But Cardio CT exposes you to large radiation and MRI is not accurate. Cardio CT is improving and the radiation has been reduced by more than 50% over time. The hope is that in the coming years, it will be a viable option. MRI is also improving and may turn out to be an even better option.
But for now, assume you have heart disease if you have a family history, if you have cholesterol above 150, high blood pressure or diabetes and you should change your life style. I guess I am describing a large majority of people who consume the Standard American Diet.
Stage 0 is defined as no visible heart disease based on a heart scan, meaning no visible plaque buildup in the heart's arteries. Stage 1 would be considered mild heart disease, in which one to two blood vessels may be blocked less than 30 percent. Stage 2 is defined as moderate heart disease, with blockage between 30 and 49 percent in one to two vessels, or mild blockage in three blood vessels. At stage 3, a person would be considered to have severe heart disease, meaning one to two coronary arteries show more than 50 percent narrowing of the vessels diameter, or three blood vessels are moderately blocked in the 30 to 49 percent range. Very severe heart disease, or stage 4, has three or more vessels with over 50 percent blockage.
Based on data from the U.K. review and many others, Zadeh says, at each increasing stage, the risk of heart attack or death per year goes up, starting from a less than 0.1 percent risk a year among those at stage 0, 0.1 to 0.9 percent risk within a year at stage 1, 1 to 1.9 percent risk at stage 2, 2 to 3.9 percent risk at stage 3, and 4 percent or greater risk of heart attack or death for those at stage 4. The risks in these stages were established by coronary angiography from both cardiac catheterization and noninvasive CT scanning data.
"What we and others can conclude from such evidence is that far less severe blockages can cause trouble because the sticky plaques can lead to the clumping of blood cells in coronary arteries, producing small clots that may cause chest pain and ultimately may lead to a heart attack," says
http://www.news-medical.net/news/20170112/Experts-suggest-new-five-stage-system-of-classifying-patients-at-risk-for-heart-attack.aspx