Only advanced atherosclerosis cannot be reversed, totally. It can be brought under control, stopped, and slightly reversed. If caught early, it can be reversed entirely. Some of the risk factors for coronary heart disease, such as genetic disposition, are beyond a person's control. As we discovered with cancer, genetic disposition is overridden by lifestyle and diet.
High cholesterol causes hardening of the arteries.
Nutritional deficiencies cause hardening of the arteries. Cholesterol plays only a secondary role in this process. An aspirin a day will prevent heart disease. Aspirin can help you stave off a heart attack. In the studies performed on aspirin, plain aspirin did not work.