From the Guidelines
A calcium score of 0 indicates no detectable calcium and very low cardiovascular risk, while scores above 100 represent increasing levels of calcification and risk, with scores above 400 considered severe. Calcium score values, also known as coronary artery calcium (CAC) scores, provide important information about the amount of calcified plaque in your coronary arteries, as demonstrated by Shaw et al 1 who found that a CAC score is an independent predictor of death that increases proportionally relative to baseline. The CAC score is a valuable tool for assessing cardiovascular risk, particularly in patients with intermediate risk factors, as it can help guide treatment decisions regarding preventive therapies like statins, aspirin, or lifestyle modifications.
Some key points to consider when interpreting calcium score values include:
- A score of 0 indicates no detectable calcium and very low cardiovascular risk, with a 10-year adjusted survival rate of 99.4% as demonstrated by Budoff et al 1
- Scores between 1-100 represent mild calcification with moderate risk
- Scores between 101-400 indicate moderate to severe calcification with increased risk, with an adjusted relative risk of 1.7 to 4 as demonstrated by Shaw et al 1
- Scores above 400 are considered severe and indicate extensive calcification with high cardiovascular risk.
The test is performed using a specialized CT scan without contrast and provides an objective measure of atherosclerosis that has developed over time, as supported by the MESA study 1 which showed CAC as an independent predictor of cerebrovascular events. Higher scores generally warrant more aggressive preventive strategies, while very low scores might allow for less intensive approaches depending on other risk factors, as suggested by the AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA guideline 1.
From the Research
Calcium Score Values
- Calcium score values are used to assess the risk of cardiovascular disease, with different categories of risk developed based on the score [ 2 ].
- The categories of risk include:
- CAC = 0, indicating no coronary artery calcium
- CAC 1-10, indicating minimal coronary artery calcium
- CAC 11-100, indicating mild coronary artery calcium
- CAC > 100, indicating significant coronary artery calcium
- Studies have shown that individuals with minimal calcium scores (1-10) have a greater noncalcified coronary plaque and total plaque volume than individuals with a calcium score of zero, placing them at higher coronary vascular disease risk [ 2 ].
- The use of coronary artery calcium scoring can help guide statin therapy allocation according to risk-enhancing factors, with a CAC score of 0 indicating a lower risk of cardiovascular disease [ 3 ].
Clinical Significance
- The presence of coronary artery calcium is a highly specific feature of coronary atherosclerosis, and CAC scoring has emerged as a widely available, consistent, and reproducible means of assessing risk for major cardiovascular outcomes [ 4 ].
- CAC scoring can be used to clarify risk in patients with severe hypercholesterolemia, with a higher CAC category associated with increased statin use after CAC scoring [ 5 ].
- The use of CAC scoring can help identify individuals at intermediate risk of atherosclerotic cardiovascular disease who may benefit from statin therapy, with significant improvements in the reclassification and discrimination of incident ASCVD [ 3 ].
Risk Assessment
- Coronary artery calcium scoring can be used to assess the risk of cardiovascular disease in asymptomatic individuals, with a CAC score of 0 indicating a lower risk of cardiovascular disease [ 6 ].
- The use of CAC scoring can help guide the allocation of statin therapy according to risk-enhancing factors, with a CAC score of 0 indicating a lower risk of cardiovascular disease [ 3 ].
- CAC scoring can be used in combination with traditional risk factors to improve the assessment of cardiovascular risk, with significant improvements in the reclassification and discrimination of incident ASCVD [ 3 ].