The Use of Calcium Scoring in Preventive Cardiology and Risk Assessment

What is a Coronary Artery Calcium (CAC) score?

A CAC score measures the amount of calcium in the walls of the coronary arteries, which are the blood vessels that supply blood to the heart. CAC is measured using a non-invasive CT scan. A higher CAC score indicates a greater buildup of calcium, which is a sign of atherosclerosis (plaque buildup in the arteries). Calcium gets deposited in the artery wall, which contributes to the formation of more complicated, older plaques as part of the healing and stabilization process. Atherosclerosis increases the risk of heart attack, stroke, and other cardiovascular events.

How is CAC scoring used to assess cardiovascular risk?

CAC scoring assesses cardiovascular risk by providing additional information about the presence and extent of atherosclerosis beyond traditional risk factors. While traditional risk factors like age, sex, cholesterol levels, and blood pressure can estimate the likelihood of developing cardiovascular disease, CAC scoring directly visualizes the presence of plaque in the arteries.

A CAC score of 0 indicates the absence of detectable plaque, generally associated with a low risk of cardiovascular events in the near future. Conversely, a CAC score above 0 suggests the presence of plaque, and the higher the score, the greater the risk and severity of potential blockages.

CAC scoring can be particularly useful for individuals with intermediate risk based on traditional factors. A high CAC score in these individuals may warrant more aggressive preventive measures, such as statin therapy. Conversely, a CAC score of 0 may allow for a less aggressive approach.

How does CAC scoring compare to other risk assessment tools?

CAC scoring has been shown to be a stronger predictor of coronary heart disease (CHD) and atherosclerotic cardiovascular disease (ASCVD) than traditional risk factors alone. The strength of calcium scoring is that it takes some of the guesswork out of the equation. Not all patients with elevated cholesterol or family history have dangerous plaque or high plaque burden. Studies have found that the higher the CAC score, the higher the risk. Typical scores can go from zero to 2,000. Scores are typically determined by looking at percentile compared to other people in that age category.

 

How CAC Score Results Guide Treatment Decisions

CAC score results can be used to guide decisions about treatments including statins, aspirin nutraceuticals, and the extent to which the patient should follow strict diet and lifestyle guidelines.

• High CAC Score: A high CAC score, even in individuals with low or intermediate risk based on traditional factors, suggests a higher risk of CHD events. Statin therapy is generally recommended for these individuals to reduce the risk of future events. Alternatives to statins may also be used, such as red yeast rice, niacin, tocotrienols, green tea garlic, and more. Zetia is a a good drug option, as well as PCSK9 inhibitors; the latest cholesterol drug. CAC score is also a predictor of all-cause mortality. In a 6.8-year study, patients with a CAC score of 101 to 400 or a score greater than 400 had a 5.6- or 9.7-fold greater risk of all-cause mortality, respectively.
• Low CAC Score: A CAC score of 0, especially in individuals with intermediate risk, indicates a lower risk of CHD events. Statin therapy may not be necessary for these individuals, and lifestyle modifications might be sufficient.
• Patients at intermediate risk: In some cases it is not clear whether a patient should be treated aggressively or not. In these cases doing calcium scoring can help with decision-making. This way, a personalized approach can be implemented. Unfortunately, calcium scoring is just beginning to get into conventional medicine even though it has been around for 30 years!

The Limitations of Calcium Scoring

While CAC scoring is a valuable tool, it’s important to be aware of its limitations:

• Doesn’t predict plaque rupture: CAC scoring only measures the amount of calcified plaque. It cannot predict which plaques are likely to rupture and cause a heart attack.
• Radiation exposure: CAC scoring involves radiation exposure from the CT scan. The radiation dose is low, but it’s still a consideration, especially for younger individuals.
• Detecting rupture prone plaque: Calcium scoring cannot detect uncalcified plaque which is the type that is vulnerable and rupture prone. It is this type that causes most heart attacks. Calcium scoring is best used as an initial screening tool.
• Does not measure degree of stenosis: This test just looks for the volume and density of plaque in parts of the artery but does not measure the percent blockage. It is for this reason that it is just a screening tool. A patient with a high score should consider a coronary CT angiogram. I have ordered quite a few of these at our office.

CAC density can provide additional information about risk.

• Lower Density = Higher Risk: Research suggests that plaques with lower calcium density may be more prone to rupture and cause heart attacks.
• Higher Density = More Stable: Plaques with higher calcium density are considered more stable and less likely to rupture. Endurance athletes tend to have this type of plaque, which helps explain why that population has fewer heart attacks despite having extensive calcified arteries.

How Age Influences CAC Density

Calcium density increases with age, reflecting the natural progression of atherosclerosis. As individuals age, the plaque in their arteries tends to become more calcified and denser. However, this is not always the case in a patient who is not adequately treated. It gets complicated because the rapid healing of plaque causes hypercalcification. The calcification process helps stabilize plaque. It is for this reason that coronary CT angiography is the next step in our practice.

It’s important to note that the relationship between age and calcium density doesn’t mean that high calcium density in older individuals is necessarily benign. High calcium density still indicates the presence of plaque, and other factors, such as plaque volume and location, and contributes to the overall risk.

Who Should Get Calcium Scoring

It depends. If you have high cholesterol and/or a family history of a first-degree relative having a heart attack or stroke below the age of sixty, then it makes sense to do an initial screening calcium score. Keep in mind that a score of zero does not mean there is not plaque, it just means there is not older plaque that is calcified and has started to heal.

Contact us to schedule your calcium scoring test: 303-884-7557