Clinical Classification of Coronary Artery Disease: Who Should Be Treated?

Coronary heart disease affects 2–6% of the general population; in the USA, it is responsible for more than 400,000 deaths each year. Epidemiological data show that, annually, approximately 785,000 Americans experience a heart attack [{cr1}], underlining the urgency of detection, quantification, and the prompt initiation of treatment of ischemic heart disease. Obstructive coronary disease causes an imbalance between oxygen supply and oxygen consumption, leading to the various clinical syndromes described below. Atherosclerotic plaque growth proceeds from the accumulation of fatty deposits, cholesterol, and cellular waste products in the inner layer of the coronary arteries. Other substances, such as calcium, can also be found in the fatty streaks. Over time, fibrous atherosclerotic plaques develop, narrowing the arteries and thereby limiting coronary blood flow. At this stage, coronary artery disease can be asymptomatic or associated with angina pectoris, and it is typically accompanied by calcification of the atherosclerotic plaque. Calcification is an active process, a part of the atherosclerotic burden, similar to metaphysis in bone formation. In addition, the plaque may rupture, due to the atherosclerotic burden, leading to vessel occlusion, blood flow interruption, and acute coronary syndrome.