From the Guidelines
A coronary calcium score primarily indicates the presence of older, stable plaques rather than active, vulnerable ones. The test detects calcium deposits in the coronary arteries using a specialized CT scan, assigning a numerical score that reflects the total amount of calcification present [ 1 ]. These calcified plaques typically represent the healing process of atherosclerosis, where calcium has been deposited over time. Active or vulnerable plaques, which are more likely to rupture and cause heart attacks, often contain more lipid-rich material and less calcium, making them less visible on calcium scoring [ 1 ].
Key Points to Consider
- The presence of coronary calcium is not identical to the presence of relevant coronary stenosis, as its specificity regarding the presence of ≥50% stenosis is only 50% [ 1 ].
- A coronary calcium score of zero has a high negative predictive value for ruling out significant coronary narrowing, but recent studies have questioned this, suggesting that significant stenosis can occur in the absence of coronary calcium [ 1 ].
- The 2019 ACC/AHA guideline recommends using coronary artery calcium measurement as a tool for refining risk assessment in individuals with intermediate predicted risk, as it can reclassify risk upward or downward [ 1 ].
Clinical Implications
- The absence of coronary artery calcium does not rule out noncalcified plaque, and clinical judgment about risk should prevail [ 1 ].
- For detecting active, vulnerable plaques, other imaging techniques like coronary CT angiography, intravascular ultrasound, or optical coherence tomography may be more appropriate.
- The calcium score is valuable for assessing overall coronary artery disease burden and long-term risk but is not designed to identify which plaques might currently be unstable or at risk of rupturing.
From the Research
Coronary Calcium Score
A coronary calcium score is a measure of the amount of calcium in the coronary arteries, which is a marker of atherosclerosis. The score can be used to assess the risk of cardiovascular disease.
Active vs Old Plaques
- The coronary calcium score does not directly distinguish between active and old plaques 2, 3.
- However, a higher coronary calcium score is associated with a higher risk of cardiovascular events, suggesting that the score may be indicative of more advanced atherosclerosis 4, 5.
- The score can be used in combination with other risk factors to estimate the risk of coronary heart disease and guide treatment decisions 5, 6.
Interpretation of Coronary Calcium Score
- A coronary calcium score of 0 is associated with a low risk of cardiovascular events 4, 5.
- A score of 1-99 is associated with a moderate risk, while a score of 100 or higher is associated with a high risk 6.
- The score can be used to reclassify individuals into different risk categories and guide treatment decisions, such as the use of statins or aspirin 2, 3, 4, 6.