What Is a Calcium Scoring Test & Do I Need One?

What Is a Calcium Scoring Test & Do I Need One?

You probably know your height and weight and may even have your typical blood pressure readings and most recent cholesterol scores memorized. But another number might be even more important for assessing your risk of heart attack or stroke.

The coronary artery calcium (CAC) score measures the amount of calcified plaque you have in those arteries, which is essential because coronary plaque is the leading underlying cause of — or precursor to — atherosclerotic cardiovascular disease (ASCVD) events such as heart attacks and strokes. *

Your calcium score can range from zero to infinity and is proportional to your risk of having such an event for up to 15 years. People with no coronary artery calcium — even those with risk factors like diabetes, obesity, or advanced age — have the low absolute risk of ASCVD events or the lowest among individuals with similar characteristics. In contrast, people with high CAC scores have an elevated risk of ASCVD, even if they’ve never had any symptoms of heart disease, and appear to be the picture of health. **

A calcium test may be the most accurate predictor, or biomarker, of ASCVD risk to date — at least of the safe, non-invasive, and relatively inexpensive variety. But not everyone needs one, and not everyone who could benefit from one knows about it.

Here’s what you need to know about this test, whether you need one, and what the results might mean.

Wait, isn’t calcium a good thing?

Good question! Calcium in your bones and the food you eat is a good thing, yes. Calcium in your arteries, not so much.

The amount of CAC is a measure of coronary artery plaque, a waxy substance that doesn’t directly show up in a CT scan. However, because plaque is a mixture of fat and calcium, over time, the calcium begins to leave traces, or deposits, inside the artery. The innermost layer of the artery becomes calcified, and this can be detected by CT scan in the same way that X-rays look through your skin and show your bones. *

A buildup of plaque can clog your arteries, which will slow your blood flow and prevent certain areas of your heart from receiving proper oxygen levels. The plaque deposits also can cause a blood clot which may trigger a heart attack. Because the CAC score gives an indirect measure of the burden of plaque in the coronary arteries, determining your calcium score is a beneficial way to predict the likelihood of a future heart attack or stroke.*

I already know I have a risk factor for heart attack or stroke. Why do I need this test?

The traditional risk assessment model looks at your demographic information, family history, health conditions, lifestyle, and blood work to help estimate your risk. It doesn’t measure the actual burden of plaque in your arteries and isn’t highly accurate at predicting who will have calcified plaque and who won’t.

So, do I need to get a calcium score test?

The test is recommended for individuals in the intermediate risk range who would like a more precise risk assessment to help guide treatment and medication decisions.  Intermediate risk means you have at least one traditional cardiovascular risk factor, such as:

  • High blood pressure
  • High cholesterol
  • Diabetes
  • Obesity

What does the test entail?

CT scanners use X-rays, typically in modern multi-detector CT scans. The radiation exposure is usually low — like a bilateral mammogram — and no contrast dye is required.

At your appointment, you will change into a hospital gown and lie down on a special scanning table. A technologist will clean four small areas of your chest — men may need to have the areas shaved — and place sticky patches. The patches contain electrodes that monitor your heart’s electrical activity throughout the test.

What do the scores mean?

The results will need to be shared with your doctor, who should go over what they mean in detail.

* National Heart, Lung, and Blood Institute (https://www.nhlbi.nih.gov)

** American Heart Association https://www.heart.org)

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