Is a CAC Scan Right for Your Heart? Here's What You Need to Know
Coronary artery calcium scans aren't for everyone, but for the right person at the right moment, they can be a great tool for early detection.
Key Takeaways
A CAC scan is a quick, non-invasive imaging test that can detect early signs of heart disease before any symptoms appear
It's most useful if you're in a "gray zone" of cardiovascular risk and you or your provider want more information before you commit to next steps
Your score is a starting point for a conversation – one data point of many that we’ll take into consideration
Insurance coverage is inconsistent, but the out-of-pocket cost is often lower than you might expect
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by Caylin Cheney, Advanced Registered Nurse Practitioner
Heart disease is the leading cause of death globally–but it’s also preventable in most circumstances. So what if we could detect it early, maybe even before any symptoms show up?
We have a tool for that called the coronary artery calcium (CAC) scan – also sometimes called a CT calcium scan or a cardiac calcium score exam. While it’s been around for about 35 years, it’s gotten a lot more popular; in fact, four times as many CAC scans were performed in 2017 than in 2006. But I find that a lot of my patients still don’t know about it, when it can be a super powerful tool to detect heart disease early.
Let’s go through the basics:
What is a CAC scan?
Your coronary arteries are the vessels that supply blood to your heart muscle. When those arteries are healthy, they are free of blockages and flexible. Over time, fatty deposits of plaque can build up along the artery walls, usually because of high cholesterol. When this happens, your arteries become harder and narrower, putting stress on your heart–which increases your risk for a heart attack or stroke.
As that plaque accumulates, calcium attaches to it. A coronary artery calcium (or CAC) scan is a non-invasive CT imaging technique that measures calcium-containing plaque in the coronary arteries, then gives you a score on a scale from 0 to 300+ (sometimes going into the thousands in more extreme cases). Think of it like a snapshot of your cardiovascular health that can show signs of disease before you ever have symptoms.
No dye. No needles. No treadmill. The scan takes about 10–15 minutes and requires no recovery time.
It's worth knowing that a CAC scan is different from other heart tests you might have heard of. For example, an EKG or a stress test evaluates how your heart functions—its electrical activity, its response to exertion. A CAC scan looks at structure: what's actually building up in your arteries, before you ever feel it.
When should you consider getting a CAC scan?
A CAC scan isn't for everyone. It’s most useful if you're in a "gray zone" of cardiovascular risk—not obviously high or low. I tend to recommend it most often when the path forward on treatment isn’t obvious and either my patient or I am on the fence about starting statin medications to help reduce cholesterol. Pregnant people should not get a CAC scan because it does involve a low dose of radiation.
If you’re between 40–75 and your 10-year risk falls between 5% and 20%, a CAC test could be really useful to determine next steps.
But if you're obviously very low risk, the result is likely to be 0 and won't change anything. If you're already at high risk or have established heart disease, treatment decisions are usually clear without it.
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So what does it mean to be in that gray zone? Risk factors worth discussing with your provider include:
Family history of heart disease
High or elevated cholesterol
High blood pressure
Diabetes or pre-diabetes
History of smoking
Elevated lipoprotein(a)
I'd also specifically mention that chronic inflammatory conditions like lupus and rheumatoid arthritis (which are both more common in women) can be a reason to consider a CAC scan. People with an autoimmune disease may be up to three times more likely to develop cardiovascular disease than people without one – and standard risk calculators don’t always account for this.
How do you prepare for a CAC scan?
This is one of the easier tests to prepare for. Generally, you'll be asked to avoid caffeine, tobacco, and food for a few hours beforehand, since anything that elevates your heart rate can affect image quality. Wear comfortable clothing and be prepared to remove jewelry or any metals.
That's it. You'll lie on a table, the scanner will take a series of images over several minutes, and you'll be on your way.
Understanding your score
The number that comes back from your scan is called an Agatston score (named after the doctor, Arthur Agatston, who co-developed it).
Score of 0: No detectable calcium. However, this doesn't necessarily mean you’ll have zero risk forever, and there are exceptions for people with certain high-risk features like diabetes or uncontrolled hypertension.
Score of 1–99: Minimal to mild calcification and risk of heart disease. Usually, if you’re in this range, I’ll recommend lifestyle changes rather than medication, though other factors matter.
Score of 100–299: Moderate calcification and risk of heart disease. A score of 100 or above will usually mean I recommend statin medications to lower your cholesterol and improve heart health.
Score of 300+: Cardiovascular risk increases significantly at this range because a lot of plaque is evident. High-intensity statin therapy (meaning more powerful cholesterol-lowering medications) is strongly recommended.
Don’t forget: Your score is a starting point for a conversation. It’s just one piece in a larger picture that we’ll look at together.
Will my insurance cover a CAC scan?
This is one of many places where I get frustrated with the gap between clinical evidence and insurance policy.
Most commercial insurers aren't required to cover CAC scans under the Affordable Care Act, and so most don't despite the reality that it can help diagnose heart disease before a person ever shows symptoms.
The good news: this is one of the more affordable imaging tests out there. Most people pay between $100 and $150 out of pocket and a CAC scan is typically HSA-eligible, which helps reduce the cost further.
But the gap between "clinically useful" and "covered by insurance" is a real and recurring feature of American healthcare. It disproportionately affects people who are already stretched thin. That's not okay, and it's something I'll always try to help you navigate.
Are You Ready To Take Control of Your Heart Health?
While explainers are helpful, your heart is unique! We’ll work together to assess your heart health and create a personalized plan that works for you to improve (or maintain!) it. I take patients virtually across Washington state, as well as in person in Seattle.
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