A high Coronary Artery Calcium (CAC) score often causes anxiety, leading many to fear it is a “death sentence.” This is inaccurate. While a high score is a serious indicator of elevated risk, it is not a diagnosis of imminent heart attack or a predetermined outcome. The CAC score measures the presence and extent of calcified plaque in the arteries, providing a powerful snapshot of your long-term cardiovascular risk profile that empowers intervention and management.
Understanding the Coronary Artery Calcium Test
The Coronary Artery Calcium test (CAC scoring) is a non-invasive imaging procedure using a specialized computed tomography (CT) scan. This scan is performed without contrast dye and images the heart to look for calcium deposits in the walls of the coronary arteries. Atherosclerosis, the underlying disease process, involves a buildup of plaque made of fats, cholesterol, and calcium within the artery walls.
The presence of calcium is a reliable marker of chronic atherosclerosis, reflecting the total amount of plaque accumulated over time. The test primarily measures calcified plaque, which is typically older and more stable. This is distinct from soft, non-calcified plaque, which is rich in lipids and inflammatory cells and often responsible for rupturing and causing sudden heart attacks. However, the amount of calcified plaque correlates strongly with the overall atherosclerotic burden and the likelihood of future coronary events.
Decoding Your Agatston Score
The result of a Coronary Artery Calcium scan is quantified using the Agatston scoring system, which calculates a numerical value based on the area and density of the detected calcium deposits. This score, reported in Agatston units, stratifies an individual’s risk for future cardiac events over the next five to ten years. A score of zero indicates no detectable calcified plaque and a very low risk of a heart attack.
Scores between 1 and 100 represent mild plaque presence and intermediate risk, while scores in the 101 to 400 range indicate a moderate amount of plaque and a higher risk. A score greater than 400 signifies extensive plaque and a very high risk of a future event.
The Agatston score is also often reported as a percentile, comparing your score to that of other people of the same age, sex, and race. A high percentile, such as the 75th or higher, suggests a greater lifetime risk trajectory relative to peers, even if the absolute score is low.
Integrating the Score with Overall Heart Health
The Coronary Artery Calcium score is never assessed in isolation when determining overall heart health risk. Clinicians use the score alongside traditional risk factors to create a comprehensive risk profile.
Traditional factors include:
- Age and sex
- Cholesterol levels
- Blood pressure measurements
- Smoking history
- The presence of diabetes
- Family history of premature heart disease
Risk prediction tools, such as the ASCVD risk estimator, rely on these traditional factors to estimate 10-year risk. The CAC score serves as a modifier for this estimate, especially for individuals classified as having intermediate risk.
For instance, a person with intermediate risk based on traditional factors but a CAC score of zero may be reclassified to a lower risk category, potentially avoiding unnecessary medication. Conversely, an individual with low-to-intermediate traditional risk but a high CAC score is reclassified to a higher risk level. This risk modification explains why the same high score is treated differently in a younger person (suggesting accelerated disease) versus an elderly person (where some plaque is expected).
Actionable Steps for Risk Reduction
A high CAC score necessitates aggressive risk factor management to stabilize existing plaque and prevent further disease progression. This strategy combines pharmaceutical interventions and sustained lifestyle changes.
Pharmaceutical Interventions
For scores above 100, and especially above 300, statin therapy is generally recommended. Statins lower cholesterol and stabilize vulnerable plaque, making rupture less likely.
Other medications may include antiplatelet therapy with low-dose aspirin for those with a high CAC score and low bleeding risk. Aggressive control of blood pressure (target less than 130/80 mmHg) and optimization of blood sugar levels for diabetics are also integral.
Lifestyle Modifications
Lifestyle modifications are foundational. Adopting a heart-healthy diet, such as the Mediterranean or DASH diet, reduces the inflammatory burden driving plaque formation.
Regular physical activity, aiming for at least 150 minutes of moderate-intensity exercise weekly, aids cardiovascular health. For smokers, cessation is the single most impactful action to reduce heart disease risk.