Coronary Calcium Score: What To Know and Why Insurance Doesn't Cover It

Find out what a calcium score is, what it has to do with life expectancy, and who has the most to gain from this predictive test.

Your blood work is in, and your LDL cholesterol remains stubbornly elevated (or high). But your overall risk of heart disease is neither high nor low. You're on the fence about next steps. Now what?

A heart CT scan might provide the necessary information you and your healthcare provider need to decide whether statin therapy is appropriate. The ACC and American Heart Association (AHA) included the scan, called a coronary artery calcium (CAC) test, in cholesterol management guidelines published in November 2018. The results of this screening test can predict your risk of a heart attack.

The scan can help differentiate patients at moderate risk for heart disease into higher or lower-risk groups, explained Mary Norine Walsh, MD, past president of the American College of Cardiology (ACC) and medical director of heart failure and cardiac transplantation at St. Vincent Heart Center of Indiana in Indianapolis.

"That piece of information alone can't help prevent a heart attack or stroke," said Dr. Walsh. It's the action people take on those results that can make a difference.

But testing isn't universally endorsed. As the U.S. Preventive Services Task Force (USPSTF) said in July 2018, evidence was "insufficient" to weigh the benefits and harms of adding this test to traditional risk assessment measures for heart attack and stroke prevention in people without symptoms.

What Is a Coronary Calcium Scan?

The test itself is quick and non-invasive. A CT (computed tomography) scan, a type of low-dose X-ray of your coronary arteries (the blood vessels that supply blood to the heart muscle), shows "calcified" or hardened plaque that may be present. The amount of this calcified plaque is a powerful independent indicator of an individual's risk of heart attack and stroke in the following 10 years.

Based on scan results, you'll get a calcium score. Zero means there's no identifiable plaque. A score of 100 or more is a tipping point. It signals plaque is present, and statin therapy is generally recommended.

The scale itself has no upper end, said Ron Blankstein, MD, past president of the Society of Cardiovascular Computed Tomography and a preventive cardiology specialist at Brigham and Women's Hospital in Boston. He has some patients with scores well over 1,000.

Who Should Have a Coronary Calcium Test?

Coronary calcium testing doesn't replace traditional risk assessment tools that factor in things like LDL, blood pressure, and smoking. Nearly half of all Americans have at least one of these risks, according to the Centers for Disease Control and Prevention. But the CAC test can help you and your healthcare provider decide whether your risk for heart attack is high enough to consider cholesterol-lowering therapy with drugs like statins.

Statin drugs are recommended as a preventive therapy if your predicted risk of heart attack or stroke in the next 10 years exceeds certain thresholds based on data from population studies. And if your predicted risk is neither high nor low, it's a tough call. Why start a statin if your arteries are clean as a whistle?

Cardiologists favor a more personalized approach that incorporates individual "risk-enhancing" factors, including coronary calcium scores, when the statin/no statin decision isn't crystal clear.

LDL, or low-density lipoprotein, is the "bad" type of cholesterol considered a significant risk for heart disease. An LDL of less than 70 is optimal for people at high risk for heart disease, and for everyone else, the goal is less than 100. An LDL of 190 or above is "very high."

Under the 2018 AHA/ACC guidelines, calcium scoring may be an option for adult patients aged 40 to 75 without diabetes if:

  • LDL is 70 mg/dL or higher, but the risk of heart attack or stroke over the next 10 years is "uncertain."
  • LDL is between 70 and 189 mg/dL, and 10-year heart disease risk is "intermediate," but a decision about starting the therapy is uncertain.

"It's definitely something we want to use when our risk is kind of in the range where maybe we want to start a statin, maybe we don't," said Anthony Pearson, MD, a preventive cardiology specialist at Saint Louis University in St. Louis, Missouri.

What Are the Benefits?

If you're facing a statin/no statin decision, coronary calcium can help you and your healthcare provider individualize treatment, cardiologists say.

Let's say your calcium score is zero. That suggests your heart disease risk is lower than predicted. You might be able to avoid or delay statin therapy if you don't smoke, have diabetes, or have a family history of heart disease.

In fact, a 2018 retrospective study published in the Journal of the American College of Cardiology of more than 13,600 patients who were followed for almost 10 years found no clinical benefit of starting a statin in patients with a calcium score of zero.

But if you are younger than 65 and have a score greater than 100, this means "you're going to benefit a lot" from starting a statin, said Dr. Pearson. Evidence of plaque could even kick-start changes in behavior. "For example, someone who's smoking may be more motivated to quit," added Dr. Walsh.

What Are the Risks?

Every time you have a CT scan, you expose yourself to radiation. The dose is relatively low, according to the USPSTF. But it could be concerning if a patient requires repeated scans. For others, being reclassified into a high-risk category could pose "psychological harms," noted the task force.

There's also a risk that the results might provide false reassurance. Younger people with a score of zero can still have a build-up of significant premature soft or non-calcified plaque. For this reason, individuals should still follow a healthy diet and lead a healthy lifestyle.

Plus, there's a chance the scan will reveal "incidental findings," extra things that appear on the test, like a nodule on your lung. Depending on their nature, incidental findings may require follow-up scans and procedures.

Should I Have the Test?

Coronary calcium scoring has previously been considered inappropriate for young adults aged 20 to 30 years. This is because calcified plaque is unusual in this low-risk age group. However, evidence published in JAMA Cardiology in 2017 indicates that a nonzero CAC score of any level in young adults indicates a much higher risk of heart attack and death.

If you're 20 to 39, the best thing you can do is embrace a heart-healthy lifestyle. Eat your greens, get up, and move—you know the drill. Doing these things can reduce risk factors that may lead to future heart disease.

The CAC test is also not for high-risk patients. For people in this group, the guidelines call for statin therapy and sometimes other preventive medicines, along with lifestyle improvements, to ward off heart woes.

Talk to your healthcare provider about your heart disease risk. You can also estimate it using an online calculator, such as the ones offered by the ACC and the National Heart, Lung, and Blood Institute.

"Knowing your risk factors is the important first step," said Dr. Walsh.

What Does It Cost?

If you decide to get tested, you'll likely pay out of pocket. The price tag? Typically $100 to $150, said Dr. Blankstein. But self-pay rates vary widely across the nation.

As to why insurers in most states don't cover the test, Cathryn Donaldson, communications director at America's Health Insurance Plans, cited a lack of high-quality data from randomized controlled trials to demonstrate that it improves clinical outcomes and reduces the rate of cardiac "events" such as heart attacks.

Without large randomized trials to rely on, AHA/ACC turned to observational studies, which show that calcium scoring can help identify patients who may benefit from preventive treatment. (An observational study does just that, it observes people, their health, and their behaviors, while a randomized controlled trial is a true experiment in that it tests groups in different conditions and provides much more substantial evidence than an observational study.)

However, you may be in luck if you live in Texas. As of June 2022, Texas is the only state with laws ensuring insurance coverage for these tests for eligible patients. In the late 2010s and early 2020s, there was much scientific interest in demonstrating the benefits of this test. If enough evidence is provided, more states may enact laws to have these tests covered by health insurance.

Ultimately, a large number of cardiologists who specialize in preventive cardiology utilize CAC in their patients and would like to see it reimbursed. Until insurers have a change of heart about covering this test, keep managing your risk factors for heart disease and talk to your healthcare provider or cardiologist if you think this test would benefit you.

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