Coronary artery calcification involves the buildup of calcium deposits within the walls of the arteries supplying blood to the heart. This accumulation signals the presence of atherosclerosis, a condition where plaque forms and hardens in the arteries.
What is Coronary Artery Calcification?
Coronary artery calcification (CAC) refers to the deposition of calcium in the coronary arteries, which deliver oxygen-rich blood to the heart muscle. This calcium differs from bone calcium; it is a component of atherosclerotic plaque. Atherosclerosis is a chronic inflammatory disease characterized by the buildup of fatty substances, cholesterol, and other materials, including calcium, within artery walls.
The process of CAC formation is closely linked to atherosclerosis. Fatty streaks develop in the arterial lining, progressing into complex plaques over time. Calcium deposits early, serving as a marker for the overall atherosclerotic burden. These deposits contribute to arterial hardening and narrowing, impeding blood flow.
What Makes it Severe?
The severity of coronary artery calcification is primarily quantified using a measurement known as the Coronary Artery Calcium (CAC) score. This score is derived from a specialized computed tomography (CT) scan that measures calcified plaque in the coronary arteries. The Agatston score considers both the area and density of calcium deposits.
Different score ranges indicate varying degrees of calcification severity. A score of zero signifies no detectable calcification, indicating a very low risk of coronary artery disease. Scores between 1 and 99 suggest mild disease, while scores from 100 to 399 indicate moderate calcification. A CAC score of 400 or higher is considered severe, reflecting a substantial burden of atherosclerotic plaque.
Why Severity Matters
The severity of coronary artery calcification is a significant indicator of future cardiovascular events. A higher CAC score, particularly one classified as severe (400 or more), strongly predicts an increased risk of outcomes such as heart attack and stroke. This is because extensive calcification signifies advanced atherosclerosis, where plaques have accumulated and hardened considerably within the arteries.
Severe calcification can lead to reduced blood flow to the heart muscle, as hardened arteries lose elasticity and become narrower. This arterial stiffness can also increase pressures within the heart’s blood vessels. Furthermore, significant calcium indicates a greater likelihood of plaque instability and potential rupture, which can trigger blood clot formation and lead to acute cardiovascular events. The CAC score acts as an independent risk factor for cardiovascular mortality, providing valuable information beyond traditional risk factors.
How Coronary Calcification is Identified
Coronary artery calcification is primarily identified and quantified using a non-contrast cardiac computed tomography (CT) scan, commonly known as a calcium score scan or heart scan. This imaging test is quick and non-invasive. During the procedure, the patient lies on a table that slides into a CT scanner, and images are taken of the heart.
The CT scan measures the amount of calcium in the coronary arteries. Images are analyzed by specialized software to calculate the Agatston score, which quantifies the extent and density of calcification. This test provides detailed information about the presence and severity of atherosclerotic plaque, even before symptoms of heart disease may appear.