It is well known that good forms of cholesterol exist, and the classic example is HDL Cholesterol. However, it is not known how HDL protects from heart attacks.
It has been suggested that HDL takes cholesterol back to the liver so that the cholesterol can be destroyed, a process called reverse cholesterol transport. One of the sources from where HDL grabs this cholesterol is from the fat in the certain white blood cells called Macrophages residing within the lipid masses that block various blood vessels.
New research published in the prestigious New England Journal of Medicine suggests that lack of cholesterol efflux, or the ability of HDL to accept cholesterol from macrophages may lead to heart attacks. This is because in the absence of the aforementioned cholesterol efflux, HDL is not able to grab the cholesterol from macrophages. Thus more and more cholesterol accumulate in the blood vessels supplying the heart and blocks them.