Coronary Artery Calcification
Coronary artery calcification is the buildup of calcium deposits in the walls of the coronary arteries—the blood vessels that supply the heart muscle with oxygen and nutrients. These calcium deposits develop within atherosclerotic plaques as part of the body’s response to vessel wall injury and inflammation. While calcification itself doesn’t cause symptoms, it serves as a marker of atherosclerosis and indicates the presence of coronary artery disease. The amount of calcium, measured through coronary calcium scoring, directly correlates with atherosclerotic plaque burden and helps predict future risk of heart attack and other cardiovascular events.
What is it?
Coronary artery calcification occurs as calcium phosphate crystals deposit within atherosclerotic plaques in the coronary artery walls. The process begins when the arterial endothelium is injured by factors such as high cholesterol, high blood pressure, smoking, or diabetes. This injury initiates an inflammatory response leading to the formation of fatty plaques. Over time, as these plaques mature, calcium accumulates through processes similar to bone formation. Inflammatory cells release factors that promote calcium deposition, and dying cells within plaques release calcium-binding proteins. The calcification can occur in different plaque layers—within the lipid core, in the fibrous cap, or throughout the plaque.
The extent of coronary calcification is quantified using the Agatston score (coronary artery calcium or CAC score), calculated from a non-contrast CT scan of the heart. Scores are interpreted as follows: 0 indicates no detectable calcification (very low risk); 1-99 suggests mild calcification (low to moderate risk); 100-399 indicates moderate calcification (moderate to high risk); and 400 or greater represents extensive calcification (high risk for cardiovascular events). The score is age- and gender-specific, with higher scores expected in older individuals. Risk factors for coronary calcification mirror those for atherosclerosis: age (calcification increases with age, more common after 40 in men and 50 in women), male gender (men develop calcification earlier), family history of heart disease, high LDL cholesterol and triglycerides, low HDL cholesterol, high blood pressure, diabetes or metabolic syndrome, smoking, obesity, sedentary lifestyle, chronic kidney disease, and inflammatory conditions. Importantly, coronary calcification is essentially irreversible—once calcium deposits, they remain permanently, though plaque stabilization can be achieved with treatment.
Important to Know
Coronary artery calcification itself causes no symptoms. However, it indicates the presence of atherosclerotic coronary artery disease, which can lead to symptoms if arteries become significantly narrowed: chest pain or pressure (angina), especially with exertion or stress; shortness of breath during physical activity; fatigue; and in cases of complete blockage, heart attack with symptoms including severe chest pain, pain radiating to arms, jaw, or back, nausea, sweating, and shortness of breath. The primary value of detecting coronary calcification is risk stratification—helping determine who would benefit most from aggressive preventive treatments. Diagnosis is made through coronary artery calcium (CAC) scoring, a quick, non-invasive CT scan requiring no contrast injection or special preparation, taking only 5-10 minutes. The scan uses specialized software to detect and quantify calcium deposits in the coronary arteries. CAC scoring is most useful for asymptomatic individuals at intermediate risk for cardiovascular disease (based on traditional risk factors) to better refine their risk assessment. It’s generally not recommended for low-risk individuals (score would likely be zero without changing management) or high-risk individuals (already warrant aggressive treatment regardless of score) or those with known coronary disease. Treatment doesn’t remove existing calcium but focuses on preventing disease progression and reducing event risk through lifestyle modifications including heart-healthy diet (Mediterranean or DASH diet), regular exercise (at least 150 minutes moderate activity weekly), smoking cessation, weight management, and stress reduction. Medications are cornerstone therapy: statins to lower cholesterol and stabilize plaques (even with normal cholesterol if CAC score is elevated), antihypertensive medications to achieve blood pressure under 130/80 mmHg, antiplatelet therapy (aspirin) in select patients, and glucose control for diabetics. The presence of any calcium (CAC score greater than 0) in younger individuals (men under 55, women under 65) or scores above the 75th percentile for age and gender warrant aggressive risk factor modification. High scores (over 400) or very high scores (over 1000) indicate established coronary disease and high event risk, warranting consideration of further testing such as stress testing or coronary CT angiography, especially if symptoms are present. Prognosis correlates strongly with CAC score—a score of 0 confers very low risk (less than 1% annual event rate), while scores over 400 carry significantly elevated risk (over 2-3% annual event rate). However, aggressive risk factor management can substantially reduce this risk. Serial calcium scoring (repeating every 5-10 years) can track disease progression, with stable or slowly progressive scores indicating effective management, while rapid progression suggests need for intensified treatment.