Coronary Calcium Scoring: An Emerging Screening Tool

Coronary artery calcium (CAC) scoring is a specialized CT scan that measures calcium deposits in the coronary arteries. As an emerging tool in cardiovascular risk assessment, it can provide valuable information for certain people trying to understand their heart disease risk. However, it's not appropriate for everyone, and understanding both its benefits and limitations is essential.

What Is Coronary Calcium Scoring?

When plaque builds up in the coronary arteries (the blood vessels that supply your heart muscle), calcium deposits often form within that plaque. These calcium deposits can be detected and measured using a specialized CT scan.

The test uses computed tomography to create detailed images of your heart and coronary arteries. A computer then calculates the amount of calcium present, generating a calcium score. This score reflects the total amount of calcified plaque in your coronary arteries.

The test is quick, non-invasive, and requires no injections or dye. You simply lie on a table that slides through a CT scanner for a few minutes while images are captured.

Understanding the Scores

Your CAC score is reported as a number, with higher scores indicating more calcium and therefore more plaque:

Score of 0

No calcium detected. This suggests very low risk of coronary artery disease and a low risk of heart attack in the next 5-10 years. However, it doesn't completely rule out the presence of non-calcified plaque.

Score of 1-99

Mild amount of calcium detected, indicating mild plaque buildup. This suggests low to moderate risk and may warrant discussion about risk factor modification.

Score of 100-299

Moderate amount of calcium detected, indicating moderate plaque buildup. This suggests moderate risk of heart attack, and risk factor management becomes more important.

Score of 300 or Higher

Large amount of calcium detected, indicating extensive plaque buildup. This suggests high risk of heart attack, and aggressive risk factor management along with potential medication is typically recommended.

Percentile Rankings

Your score is also often compared to others of your age and sex. For example, a score in the 75th percentile means you have more calcium than 75% of people in your age and sex group. This percentile ranking can provide additional context for your individual result.

Who Might Benefit From CAC Scoring

Coronary calcium scoring isn't recommended for everyone. It's most useful for people whose cardiovascular risk assessment is uncertain based on traditional risk factors alone—what doctors call "intermediate risk."

Good Candidates

• Adults ages 40-75 without known cardiovascular disease whose 10-year risk falls in an intermediate range
• People whose risk assessment is unclear and who are trying to decide about preventive medications like statins
• Those with a family history of early heart disease
• People who want to better understand their cardiovascular risk for lifestyle planning

Not Recommended For

• People already known to have coronary artery disease—they need treatment regardless of their calcium score
• Very young adults (under 40) where calcium hasn't had time to accumulate even if disease is present
• People already clearly at high risk who should be on preventive therapy regardless of the score
• People at very low risk where the test is unlikely to change management

How the Test Is Used

CAC scoring helps refine cardiovascular risk estimates. Here's how it might influence care decisions:

Informing Medication Decisions

If your traditional risk factors suggest you might benefit from a statin but the decision isn't clear-cut, a calcium score can help. A score of zero might support holding off on medication and focusing on lifestyle changes, while an elevated score might tip the balance toward starting preventive medication.

Motivating Lifestyle Changes

For some people, seeing concrete evidence of plaque buildup provides powerful motivation to quit smoking, improve diet, increase exercise, or better control blood pressure and cholesterol. The visual nature of the test results can make heart disease risk feel more real and immediate.

Guiding Intensity of Risk Factor Management

A high calcium score suggests the need for more aggressive management of blood pressure, cholesterol, and other risk factors, while a zero score might allow for a less intensive approach in borderline cases.

What CAC Scoring Cannot Tell You

Understanding the limitations of calcium scoring is as important as understanding what it can reveal:

It Doesn't Show Blockages Directly

CAC scoring measures calcium in plaque, not the degree of artery narrowing. Two people with the same calcium score might have very different degrees of blockage. Some plaques contain lots of calcium but don't narrow the artery significantly, while others might cause severe narrowing with less calcium.

Soft Plaque Isn't Detected

The test only detects calcified plaque. Non-calcified or "soft" plaque, which can sometimes be more prone to rupture, doesn't show up on this scan. This is particularly relevant in younger people, where plaque may not yet be calcified.

It Doesn't Predict When Events Might Occur

While a higher score indicates higher risk, it can't tell you whether a heart attack might happen next week, next year, or many years from now. It's a risk assessment tool, not a prediction of imminent events.

Scores Can Only Go Up

Once calcium has deposited in your arteries, it doesn't go away. Even with excellent risk factor control, your calcium score can only stay the same or increase over time. This is why repeat scanning isn't typically recommended—there's no "improvement" to measure.

The Test Procedure

Getting a CAC score is quick and straightforward:

Preparation

Minimal preparation is needed. Avoid caffeine for a few hours before the test, as it can affect your heart rate. Wear comfortable clothing without metal fasteners in the chest area.

During the Scan

You'll lie on your back on a movable table. ECG electrodes are placed on your chest to synchronize image capture with your heartbeat. The table moves through the CT scanner while images are taken. The actual scanning takes only a few minutes, and you'll need to hold your breath briefly during image acquisition.

After the Test

You can resume all normal activities immediately. A radiologist will analyze the images and calculate your score, which your doctor will typically review with you at a follow-up appointment.

Radiation Exposure

CAC scoring involves exposure to radiation, though modern scanners use relatively low doses—typically similar to what you'd receive from natural background radiation over several months.

While this exposure is small, it's not zero. The potential benefits should outweigh the risks, which is why the test should be reserved for situations where it's likely to provide useful information that will influence your care.

Cost Considerations

Coronary calcium scoring is generally not covered by insurance when used for screening in people without symptoms. Costs typically range from $75-$400, depending on location and facility. Some medical centers offer calcium scoring as part of health screening packages.

Since you'll likely pay out of pocket, consider whether the information will meaningfully impact your health decisions. If you're already committed to heart-healthy lifestyle changes or already taking appropriate preventive medications, the test may not provide actionable new information.

Interpreting Results in Context

Your calcium score should be interpreted alongside your complete risk profile, not in isolation. Important considerations include:

• Your age: Calcium accumulates with age, so a score considered high for a 45-year-old might be average for a 70-year-old
• Traditional risk factors: Your blood pressure, cholesterol, smoking status, diabetes, and family history all remain important
• Symptoms: If you have chest pain or other cardiac symptoms, you need symptom evaluation regardless of your calcium score
• Overall health goals: How the results fit into your broader health management strategy

The Conversation With Your Doctor

If you're considering coronary calcium scoring, discuss these questions with your healthcare provider:

• Based on my risk factors, am I a good candidate for calcium scoring?
• How might the results change my treatment plan?
• What would we do differently if my score is zero versus elevated?
• Are there other tests that might provide better information for my situation?
• What are the costs, and will insurance cover it?

The Bottom Line

Coronary calcium scoring can be a valuable tool for certain people navigating cardiovascular risk assessment. Its greatest value lies in helping refine risk estimates for those in the uncertain middle ground—not clearly high risk but not clearly low risk either.

The test works best when used as one piece of information in a comprehensive approach to cardiovascular health. It shouldn't replace fundamental preventive measures like not smoking, eating well, exercising regularly, and managing blood pressure and cholesterol.

For the right person at the right time, calcium scoring can provide clarity and motivation. But it's not a crystal ball, and it's not appropriate for everyone. Work with your healthcare provider to determine whether it makes sense for your individual situation.