The Coronary Artery Calcium (CAC) score is a diagnostic tool used to assess an individual’s long-term cardiovascular risk. This non-invasive measure quantifies the amount of calcified plaque present in the coronary arteries, which is a direct sign of atherosclerosis. A high CAC score indicates that the disease process is underway, offering a window for intervention. While receiving a high score can be alarming, it serves as an early warning that allows for aggressive, informed action to protect heart health. The score helps physicians and patients determine a precise course of preventive care beyond traditional risk factor estimates.
Understanding the Coronary Artery Calcium Score
The CAC score is determined through a fast, non-invasive computed tomography (CT) scan of the chest. This scan detects and measures the specks of calcium accumulated in the walls of the coronary arteries. The resulting measurement is known as the Agatston score, which combines the number, size, and density of the deposits into a single numerical value.
The Agatston score is categorized into risk groups for interpretation. A score of zero indicates no detectable calcified plaque and is associated with the lowest risk of future cardiac events. Scores from 1 to 99 represent minimal or mild plaque burden. Moderate risk is associated with scores between 100 and 300, suggesting an established presence of coronary atherosclerosis.
A score exceeding 300 or 400 is considered a high burden of calcified plaque and places an individual in the highest risk category for major cardiovascular events. This number provides a clear picture of the physical extent of the disease. The score is a powerful predictor because it directly measures the underlying disease, rather than just estimating risk from factors like age or cholesterol levels.
Mortality Risk and Age-Based Interpretation
A high CAC score is strongly correlated with an increased risk of Major Adverse Cardiovascular Events (MACE), including heart attack, stroke, and cardiac death. Compared to an individual with a score of zero, a person with a CAC score greater than 400 faces a significantly higher mortality risk, often increasing the likelihood of a cardiac event five to ten-fold. This stratification is a powerful tool for predicting long-term outcomes.
The key to interpreting a high score lies in its relation to a person’s age and gender. A raw score considered high in a younger individual may be expected in an older person. Therefore, the absolute Agatston score is often paired with a percentile ranking, which compares the score to others of the same age and gender.
For example, a score of 100 in a 45-year-old male might place him at the 75th percentile, meaning his calcium burden is higher than 75% of his peers. This suggests a rapidly accelerating disease process. Conversely, the same score of 100 in a male over 75 years old may fall below the 25th percentile, indicating a relatively low burden for that age group and a lower risk profile.
The predictive power of a CAC score is strongest in younger and middle-aged adults, where a high score is a more concerning finding. Even in older adults over 75, a very low score (e.g., 0–9) or a score in the lowest percentile identifies a subgroup with a significantly lower risk of mortality compared to their peers. The presence of any calcium burden substantially increases the long-term risk of events across all age groups compared to those with a score of zero.
Immediate Medical and Lifestyle Strategies
The discovery of a high CAC score requires a shift toward aggressive risk reduction strategies. The first step involves a detailed consultation with a cardiologist to review the score and integrate it with other health data, such as a full lipid panel and blood pressure readings. While a high score indicates underlying disease, it does not mean a person is on the verge of a heart attack, requiring a calm but urgent approach to management.
Medical management centers on pharmaceutical interventions to stabilize existing plaque and prevent further buildup. Aggressive lowering of low-density lipoprotein (LDL) cholesterol is primary, typically achieved through high-potency statin therapy. For individuals with a very high score (e.g., over 400), the target LDL goal is often set at an extremely low level, sometimes below 50 mg/dL.
Controlling other metabolic risk factors, such as high blood pressure and elevated blood sugar, is also a focus of treatment. Low-dose aspirin may be recommended in some cases, particularly for scores over 100, to reduce the risk of blood clot formation. However, aspirin use is a personalized decision balancing reduced cardiac risk against the risk of major bleeding.
Lifestyle Modifications
Comprehensive lifestyle modifications are important for slowing the progression of atherosclerosis. A heart-healthy eating pattern, such as the Mediterranean or DASH diet, is highly recommended, emphasizing fruits, vegetables, whole grains, and healthy fats. Regular physical activity, aiming for at least 150 minutes of moderate-intensity exercise weekly, helps manage cholesterol, weight, and blood pressure. The single most impactful change is smoking cessation, as smoking accelerates plaque buildup and destabilizes existing lesions.