What your CT calcium score can tell you about your heart

Your cholesterol is in range. Your blood pressure looks good. At your annual checkup, everything seems normal. So why might your doctor still recommend a CT calcium score test?

When it comes to understanding your heart health, standard blood tests only tell part of the story. A CT calcium score, also known as a coronary calcium score, is a useful tool for detecting calcified plaque in the coronary arteries. The presence of this plaque demonstrates coronary artery disease (CAD) and helps estimate your risk of a future heart attack, often years before symptoms appear.

What does a CT calcium score show?

Your arteries can silently accumulate cholesterol plaque for decades before there are symptoms. That buildup, called atherosclerosis, doesn't always announce itself. A coronary calcium score gives you and your doctor a measurable picture of the presence of coronary plaque.

The calcium score test uses a non-contrast CT (computed tomography) scan to detect and quantify calcified plaque in the coronary arteries, which are the vessels responsible for delivering oxygen-rich blood to your heart. The result is a number that is calculated based on the density and volume of any calcium deposits found.

It's worth noting that the score alone isn't the complete picture. Your result is interpreted alongside your age, sex, ethnicity and other risk factors, giving your doctor a more complete understanding of your cardiovascular health than a cholesterol panel can provide on its own.

What is a “good” CT calcium score?

Understandably, this is one of the first questions people ask. The short answer: a score of zero is the most reassuring outcome, which corresponds to a very low near-term risk of a cardiac event related to plaque buildup. Even though a low score is felt to suggest a lower overall risk, your doctor may treat you with medications for a score over zero.

The American Heart Association recommends considering coronary artery calcium measurement for more than 17 million Americans with borderline to intermediate 10-year cardiovascular risk. Despite that broad recommendation, awareness and use of this screening remain lower than they could be, which is one reason why having a proactive conversation with your primary care provider or cardiologist matters.

Who should consider a CT calcium scan?

The coronary calcium score test is most valuable for adults who fall into the "intermediate risk" category, those with borderline to intermediate 10-year risk (roughly 5%–20%), where it isn't entirely clear whether aggressive preventive treatment is warranted. A coronary calcium score test can either confirm that treatment makes sense or provide reassurance that a watchful, lifestyle-focused approach is sufficient for now.

In general, the test is most commonly considered for adults between the ages of 40 and 75 who have at least one of the following risk factors:

• High blood pressure
• Diabetes
• A family history of heart problems
• Elevated LDL cholesterol (above 160)
• Obesity
• A history of smoking

There are other non-traditional risk factors which may also suggest that a calcium score may be helpful.

One group that often doesn't realize they're at elevated risk are people who are living with autoimmune conditions. Research published in the Journal of the American Medical Association — Dermatology found that individuals with conditions like psoriasis, rheumatoid arthritis or Crohn's disease may develop coronary plaque earlier or at higher rates than people living without autoimmune conditions.

The body's ongoing inflammatory response can accelerate calcium buildup in the arteries in ways that traditional screening simply doesn't catch. If you have an autoimmune condition and have never discussed cardiac screening with your doctor, this is a conversation worth having.

Related: How autoimmune conditions can be a factor for heart disease—it's not just smoking 

Why calcium buildup in the heart happens

Calcium buildup in the heart's arteries is the body's response to damage or inflammation. When fatty deposits, made up of cholesterol, fat and other substances, accumulate over time, the natural response is inflammation, which causes calcification. The result is calcified plaque, which can be seen on the coronary calcium score.

This process is gradual and usually begins long before any symptoms emerge. That's why it may not be seen for years, until there is a clinical problem. You can feel completely fine while calcified plaque continues to develop inside your coronary arteries. The coronary calcium score is specifically designed to detect this early, silent stage of arterial change.

Your calcium score also provides a percentile ranking, which compares your level of plaque buildup to others in your same age, sex and ethnicity group. So even if your absolute score is moderate, that context matters to how your doctor will approach next steps.

What to expect during the calcium score test

One of the benefits of a coronary calcium score test is how straightforward it is. There's no contrast dye, no needles and no special prep except avoiding caffeine and smoking for four hours beforehand.

During the scan itself, which typically takes between 10 and 15 minutes, a technologist will ask you to hold your breath briefly a few times to ensure the images are as sharp as possible. The scanner rotates around you, capturing detailed cross-sectional images of your heart. There's no discomfort involved, and most people find the experience entirely uneventful.

After the imaging portion, you're free to resume your day as normal. A cardiologist will review the images, calculate your score and share the results with your physician, who will walk you through what the numbers mean for your individual situation.

What happens if your calcium score is elevated?

A higher calcium score is not a diagnosis, it's a signal. If your coronary calcium score comes back elevated, your doctor will work with you to build a personalized plan focused on reducing your overall cardiovascular risk.

Can you lower your calcium score?

Once calcium has been deposited in your coronary arteries, it doesn't simply disappear. The calcified plaque itself is not reversible in the way soft plaque can sometimes be reduced. A person’s score will always be the same or higher and will never go down. Once a person has a positive score, there is no reason to repeat the calcium score.

What you can meaningfully change is your overall risk. Lifestyle interventions and appropriate medications can slow or halt the progression of new plaque development, reduce inflammation, stabilize existing lesions and significantly lower your risk of a cardiac event going forward.

Actions you can take to protect your heart after an elevated calcium score include:

• Take your medications. The most important thing that can reduce your risk for future cardiac events is to be on a good cholesterol medication, particularly a statin.
• Stop smoking. If you smoke, quitting is the single most impactful change you can make for your heart health.
• Eat for your heart. Focus on whole grains, lean proteins, fruits and vegetables while reducing saturated fat, added sugar and excess sodium.
• Exercise. Consistent moderate exercise, even just for 30 minutes most days, makes a measurable difference in your cardiovascular risk over time.
• Manage blood pressure and blood sugar. Keeping both well-controlled significantly reduces the stress on your arterial walls.
• Prioritize sleep. Poor or insufficient sleep is increasingly linked to accelerated cardiovascular risk. Aim for seven to nine hours consistently.

Find out where your CT calcium score stands

If you're between the ages of 40 and 75, have one or more cardiovascular risk factors and are wondering whether there's more you should know about your heart health, a CT calcium score may be one of the smartest conversations you can have with your doctor.

Understanding your heart health is an important part of long-term wellness. A coronary calcium score test can provide an additional layer of insight, helping you and your doctor make more informed decisions about prevention and future care.

Looking to improve your heart health? Take our heart risk quiz to learn about your risk for heart disease and find a cardiologist near you.