Understanding Coronary Artery Calcium (CAC): What It Means for Your Heart Health

Coronary artery disease (CAD) remains a leading cause of cardiovascular events like heart attacks and strokes. But did you know there’s a way to detect CAD even before symptoms arise? It’s called Coronary Artery Calcium (CAC) scoring, a specialized imaging test that assesses the extent of calcium buildup in the arteries of your heart.

What is Coronary Artery Calcium (CAC)?

CAC is essentially calcium deposits within your coronary arteries, which are a sign of underlying atherosclerosis, a condition involving plaque buildup that can lead to heart disease.

Initially, these calcium deposits start at a microscopic level (about 0.5 to 15 micrometers) and progressively grow into larger calcium sheets over time. Most often, this buildup occurs in the inner lining (intimal layer) of your arteries, but can occasionally involve the artery’s muscular (medial) layer, especially in conditions like advanced kidney disease or hyperparathyroidism.

Why CAC Matters

Detecting CAC early provides critical insight into your heart health. Although the amount of calcium doesn’t always indicate the severity or activity of coronary artery disease, it strongly correlates with the overall burden of atherosclerosis.

Notably, younger patients often have more noncalcified plaques, while older patients usually exhibit more calcified plaques. Thus, a CAC score is particularly valuable for evaluating heart disease risk in middle-aged and older adults.

How is CAC Quantified?

The most common method to measure CAC is through a non-invasive test called a Coronary Artery Calcium Scan, which uses computed tomography (CT).

The Agatston scoring method is typically used:

• Measures calcium areas on CT scans.

• Assigns a score based on calcium density and area.

• Sums these scores for the entire coronary artery tree.
  

Your CAC score places you into categories reflecting heart disease risk:

• 0 Agatston units: No identifiable disease.

• 1 to 99 units: Mild disease.

• 100 to 300 units: Moderate disease.

• 301 to 999 units: Severe disease.

• ≥1000 units: Very severe disease.
  

Interestingly, dense calcified plaques might actually be more stable and therefore less risky for sudden heart events.

Incidental CAC Detection

Sometimes, CAC is found incidentally during other imaging tests, such as routine chest CT scans for lung conditions. Although these tests aren’t specifically designed for CAC scoring, their findings can provide valuable insights into heart disease risk.

Newer technologies, including automated deep learning algorithms, have improved the detection and assessment of CAC even from routine chest scans, further enhancing its usefulness for preventive care.

CAC and Heart Disease Risk

A higher CAC score directly correlates with an increased risk of cardiovascular events. For example, a CAC score over 100 significantly raises the likelihood of heart disease events within the next decade. Importantly, a CAC score of zero (often termed the “power of zero”) is one of the strongest predictors of low cardiovascular risk.

Who Should Consider CAC Screening?

CAC scans are especially valuable for asymptomatic individuals aged 40 and older, particularly those at intermediate to high risk based on traditional risk factors (such as high cholesterol, hypertension, or a family history of heart disease).

Your CAC results can profoundly influence preventive treatment decisions, such as starting or intensifying statin therapy or lifestyle changes like diet and exercise.

Benefits of CAC Imaging

• Quick and Safe: The scan is brief, typically under 5 seconds, requires minimal preparation, and involves relatively low radiation (similar to mammography).

• Non-invasive: No contrast dye or intravenous lines needed.

• Proven Predictive Value: Strongly supported by extensive research demonstrating its ability to predict future cardiovascular events.
  

Making Sense of Your CAC Results

Discussing your CAC score with your doctor helps to better understand your personal heart disease risk and guide targeted prevention strategies. Scores that indicate higher risk prompt more aggressive interventions, including lifestyle modifications and possibly medications like statins.

CAC: A Window to Prevention

CAC scoring provides a unique opportunity for proactive heart health management. By detecting atherosclerosis before symptoms emerge, individuals can undertake timely actions—dietary changes, regular exercise, smoking cessation, and medications—to dramatically reduce their risk of heart attack and stroke.

Knowing your CAC score might just be one of the most powerful steps you can take towards a healthier heart. Disclaimer:

This blog is for informational purposes only and should not be considered medical advice. Always consult your physician or qualified health professional regarding your individual health needs.