How Well Do CAC Scores Predict Heart Attack Risk?

Do you have plaque in your coronary arteries? Unless you have had symptoms that sent you to a coronary cath lab, you might not know. Over the last decade or two, though, doctors have used CT scans to calculate coronary artery calcium or CAC scores. These offer a way to determine coronary artery calcification (Journal of the American College of Cardiology, July 24, 2018).

These calcium-containing hard plaques are a visible indicator of coronary artery disease. Consequently, doctors have embraced the scores as an additional way of predicting a person’s risk for a heart attack. There is some controversy about this diagnostic screening strategy, however. Before we get into the controversy, though, you will learn how one reader used her CAC score to avoid taking statins.

How Good Are CAC Scores for Predicting the “Big One”?

Do you remember the TV show, Sanford and Son? Fred Sanford often clutched his heart claiming that he was having a heart attack, aka “The Big One!”  Doctors want to protect patients from The Big One. To do that, they rely on blood tests for things like total cholesterol (TC), LDL cholesterol, triglycerides, Lp(a),  HDL cholesterol and C-reactive protein (hs-CRP), a marker for inflammation.

In recent years, though, many cardiologists have added CAC scores to their list heart evaluation tools. There was a growing sense that a high score could predict the risk for a future heart attack.

Here is how the Mayo Clinic describes a heart scan:

“Measuring calcified plaque with a heart scan may allow your doctor to identify possible coronary artery disease before you have signs and symptoms.

“Your doctor will use your test results to determine what you need — medication or lifestyle changes — to reduce your risk of a heart attack or other heart problems.”

The Reader Used a CAC Score to Avoid Taking Statins:

Q. My doctor wants me to take a statin to lower my LDL cholesterol. I asked AI [artificial intelligence], “What questions I should ask my doctor?” One answer was to “Ask for a calcium score test.” I did that and was pleased to find my score was a perfect zero! My mind is at ease.

A. An elevated calcium score may help reveal atherosclerosis. Your perfect score probably helped ease your doctor’s concerns. Congratulations on both your good score and using AI intelligently.

Controversy About CAC Scores

A meta-analysis published in JAMA Internal Medicine (April 25, 2022) analyzed data from six studies. There were 17,961 participants and 1,043 cardiovascular disease “events.”

The authors concluded that:

“Although CACS appears to add some further discrimination to standard CVD [cardiovascular disease] risk calculators, no evidence suggests that this provides clinical benefit.”

That is stuffy doctor talk. What they are trying to say is that CAC scores may not be the holy grail for predicting or preventing heart attacks. The researchers go on to add that any modest gain from a heart scan may “often be outweighed by costs, rates of incidental findings, and radiation risks.”

Another Systematic Review of Coronary Artery Calcium

Swiss researchers writing in the journal BMJ Open (July 5, 2025) reviewed seven randomized controlled trials involving over 50,000 participants. I want to warn you that the results were a bit confusing. The study subjects did not have symptoms. The hope of the investigators was that coronary artery calcium scoring (CACS) might 1) favorably impact cardiovascular (CV) risk factor control, 2) improve health behavior and 3) reduce bad cardiovascular events.

The authors conclude:

“Our review found insufficient data to assess whether these favourable effects of screening with CACS in asymptomatic patients have a beneficial effect on clinical endpoints such as CV events or mortality, or whether reclassification with fewer indicated CV medication might even have an unfavourable effect on these endpoints.”

The bottom line seems to be that getting a CAC score did not seem to result in “improved clinical outcomes, such as reduced CV events or mortality…”

The Most Recent Systematic Review

Confused? I get it. Me too. Here is the most recent review in the journal Cureus (Jan. 12, 2026). The authors identified only 4 studies that met their criteria (asymptomatic adults of working age). They admit that:

“Our systematic review yielded only four articles for inclusion, highlighting the paucity of studies on the CAC score among asymptomatic working-age adults.”

That seems shocking given how this strategy is gaining quite a following among cardiologists. The researchers did conclude, however, that “increasing CAC score is associated with a higher risk of incident cardiac events and/or all-cause mortality in a dose-response relationship…”

In other words, the higher the score the greater the risk for heart problems.

How Much Does It Cost to Get CAC Scores?

Prices for any medical procedure can vary tremendously from one hospital to another and from one part of the country to another.

Imaging Technology News (Sept. 25, 2020) stated:

“Although CAC screening provides vital health information, it is generally not covered by insurance and can cost from $400 to $800.”

Perhaps in 2026 more insurance companies are paying. GoodRx reports that the average out-of-pocket cost “is around $100-$150.”

As for the “vital health information,” that is now up for grabs.

An accompanying editorial (JAMA Internal Medicine, April 25, 2022) added this:

“Until ongoing outcomes studies indicate a clinical benefit of CACS screening to counter balance its potential harms, we agree with the US Preventive Services Task Force and believe that adherence to the ancient medical dictum, primum non nocere, [first do no harm] should dictate a pause in adding CACS screening to standard clinical risk models for primary prevention of CVD.”

Vigorous Exercise Linked to Higher CAC Scores:

Everyone recognizes that physical activity is beneficial for the heart. People who exercise regularly are less likely to have heart attacks or die from cardiovascular causes. Vigorous exercisers seem to get particular benefit.

Research utilizing a comprehensive Korean database has turned up an interesting paradox, though (Heart, Sept. 20, 2021). Over 25,000 adults participated in the study. The investigators scanned their coronary arteries at least twice between 2011 and 2017. They also measured weight, cholesterol and blood pressure for each volunteer, who answered questions about family history and physical activity.

Those who exercised regularly—the equivalent of running 4 miles a day every day—were most likely to have high CAC scores. In addition, their scores increased more rapidly over the course of the study. The doctors don’t know what to make of the accelerated progression of coronary artery calcification in vigorous exercisers. They note, however, that physical activity is good for the cardiovascular system. While no one is about to tell people to stop exercising, it does pose a puzzle with respect to the CAC.

Statin Therapy and a CAC Paradox:

Another interesting paradox involves statin therapy to lower LDL cholesterol (JAMA Cardiology, Aug. 18, 2021). Generally, doctors prescribe cholesterol-lowering statins for patients with CAC scores at or above 100. Could statins actually increase CAC scores?

A reader shares a CAC Paradox:

Q. I am perplexed, as are my doctors. Because I take a statin, I have low total cholesterol and LDL levels. My Lp(a) level is also good, yet my arterial calcium score keeps climbing. What’s going on?

A. The statin you have been taking might be responsible for your increasing coronary artery calcification (CAC) score (Journal of the American College of Cardiology, April 7, 2015).  (This is sometimes referred to as an Agatston score.)

The CAC has traditionally been used as a risk factor for predicting heart disease. But since statins can increase the CAC, cardiologists have been looking for other explanations (Clinical Cardiology, June 2022). Some have suggested that calcified plaque is more stable and therefore less likely to lead to a heart attack.

You can learn more about the pros and cons of statins and non-drug approaches to reducing the risk of heart disease in our eGuide to Cholesterol Control and Heart Health. This online resource may be found under the Health eGuides tab.

Another study that must confuse cardiologists was published in JAMA Cardiology. It showed that people taking statins had

“larger increases of high-density calcium…plaque compared with plaques in patients not treated with statins.”

Analysis showed that when the plaque became more dense, containing more calcium, it didn’t expand in size as much. The investigators can only speculate as to why statins lead to higher CAC scores. One of our frequent guest experts, Dr. Steve Nissen, chairman of the Robert and Suzanne Tomsich Department of Cardiovascular Medicine at the Cleveland Clinic, has described why he does not routinely get calcium scores on his heart patients.

In the future, cardiologists will need to learn why both intense exercise and statin therapy appear to accelerate calcified plaque progression. After all, both presumably protect patients from heart attacks. These findings suggest that the coronary artery calcium scan might not always be the best way to predict cardiovascular complications.

Why Are Cardiologists Measuring Coronary Artery Calcium but Not Lp(a)?

We think it would be far more productive if cardiologists measured the blood lipid called lipoprotein (a). It is abbreviated Lp(a) is highly related to clogged coronary arteries and calcified heart valves. You can read more about this risk factor for cardiovascular disease at this link.

Why Haven’t You Been Tested for Lp(a) Levels?

Learn more about Lp(a) and many ways to reduce cardiovascular risks in our eGuide to Cholesterol Control and Heart Health. It is available under the Health eGuides tab at this website.