Experts Debate the Best Use of Coronary Artery Calcium Testing

Screening tests that look for evidence of possible disease are sometimes controversial. Experts often disagree about who, when and why screening tests should be administered. The value of Coronary Artery Calcium (CAC) testing continues to be debated, even as the quick scan becomes one of the more highly marketed screening tests.

CAC testing is a tool to help determine an individual’s risk of having a cardiovascular event, such as a heart attack or stroke, by assessing the amount of calcified plaque in the coronary arteries. The test consists of a relatively simple computed tomography (CT) scan without dye. It takes only 10-15 minutes, is painless, and is low-risk.

Although rarely covered by health insurance, the test isn’t a wallet-buster. It typically costs about $150 out of pocket.

So, since knowledge is power, why wouldn’t every older adult have CAC testing?

The answer is that CAC testing alone doesn’t always give patients a lot of helpful information, says Dr. Eduardo Safille, a St. Vincent's cardiologist with offices on 14th Street in Fernandina Beach.

“In cardiology, we get a lot of referrals from people who want to know what their risk is for developing a heart attack,” Dr. Safille says. “A lot of the testing we do is try to screen those people who are high-risk so we can guide and apply risk stratification to reduce their risk.”

But, Dr. Safille adds, CAC testing is best described as “a guide.”

Heart disease occurs when calcium, fat and other cellular waste products accumulate in the arteries of the heart, leading to a buildup of plaque. Plaque forms slowly over time. Individuals can have a buildup of plaque long before they develop symptoms of heart disease, according to the American Heart Association.

However, CAC testing only provides information on plaque that has calcified, Dr. Safille says.

“You get some inflammation in the inner lining of the coronary artery, and then plaque starts to accumulate inside it,” Dr. Safille says. “It gets calcified over time. The plaque becomes rigid and fixed to the walls of the artery over time. However, most heart attacks occur with soft, very unstable plaque that ruptures and blocks the artery. That is not calcified, and you’re not going to see that on a CT calcium score.”

But there is a role for CAC testing, Dr. Safille and other experts say. According to the American Heart Association guidelines, CAC testing can be helpful for people at “intermediate risk” of having a cardiovascular event. For example, the test can help a physician determine whether a patient — typically men over age 50, women over age 60 or younger people with other risk factors for heart disease — should begin statin therapy or other medications to lower cardiovascular risk.

CAC testing that produces a “score” of zero means a low risk of developing heart disease. In contrast, a score of 400 is significant and suggests the need to have other tests.

“You have to individualize the test,” Dr. Safille says. “Unless there is a really good reason to do it, I don’t think it makes sense in a 75-year-old with no symptoms.”

The American Heart Association guidelines state: “Calcium scoring isn’t recommended for routine screening of people who don’t have symptoms of heart disease and have a low risk of heart attacks unless they have a strong family history of premature coronary heart disease. If you’ve already had a heart attack, coronary bypass surgery (PDF) or a coronary stent calcium scoring won’t provide additional information.”

The U.S. Preventive Services Task Force (USPSTF) found insufficient evidence that adding the CAC score to traditional risk assessment improves patient-oriented outcomes.

Dr. Safille says he sees patients who had the test done on their own — a physician referral is not required and the test is often marketed direct-to-consumer — and come in worried about the results.

“They worry about a high score,” he says, noting that the calcified plaque, “might have been there 20 years. You can have false positives. Then you have to do another test and another test. And that’s not good for the patient.”

It’s understandable, however, that people want all the information they can to avoid serious health problems, he says.

“I get a lot of young people who have a lot of anxiety about whether they have heart disease or not,” Dr. Safille says.

The best advice, he says, is to consult with your doctor before getting CAC testing. There may be other, more helpful tests to determine your risk, such as a cardiac stress test or a CT angiography. Physicians will consider all the patient’s risk factors, such as whether they have a strong family history of heart disease, smoke, or have high blood pressure, high cholesterol or diabetes.

“You want a health care provider to help guide you because a little bit of information can be stressful and create a lot of anxiety,” Dr. Safille says. “It’s helpful if you have someone say this is what it means, don’t worry or this is what we’re going to do to help you going forward.”