Is not. There are two types of buildup. One is cholesterol deposit in a form of wax, and other is calcification which is hard. The belief of the mainstream medicine which is allopathic, is that the cholesterol deposits might be stopped by lowering cholesterol levels in the blood. The calcification is irreversible.
The belief of naturopathic medicine, is that both can not only be stopped but also reversed. Dr. Linus Pauling came up with a nutrient therapy that should be able to remove calcification from arteries. The therapy has never been medically proven, because there is nobody to finance it. Dr. Linus Pauling won a nobel prize 2 times.
According to naturopathic medicine, cholesterol deposits in the artery as a way to repair damaged tissue in the wall. That damage comes from severe stress either mental/physical, intoxication, drugs (including steroids in any dose), alcohol, contaminated water, food, toxic air. The body natural abilities to combat these free radicals is based on antioxidants, aminoaicds and vitamins but the average person does not have these nutrients in the right amounts in their body. And even at the right amounts, the load of stress these days overcome the body's ability to fix itself.