It is a way to detect silent coronary atherosclerosis before symptoms occur. The scan is quick, requires no IV contrast, and typically uses low radiation.
Cardiologist Teimuraz Apridonidze, MD, FCACCMore people are getting calcium scores to determine their risk of a heart attack or heart disease.
Many are patients who are:
- Without heart disease symptoms
- Aged 40 to 75
- Without a previous heart attack or stroke
- Not already on cholesterol drugs.
These patients also usually have been told they have a risk of heart disease, often as indicated through high LDL (low-density lipoprotein) or a strong family history of premature heart disease.
Should you get a calcium score, too?
The answer depends on a number of factors, say doctors and cardiologists at Dartmouth Hitchcock Clinics Manchester.
But they also stress that getting what is more formally called a Coronary Artery Calcium (CAC) score through a CT (computed tomography) scan is just one piece in a larger puzzle when determining your individual risk of atherosclerotic cardiovascular disease (ASCVD), which can lead to strokes and heart attacks.
What is a CAC?
Heart disease is the leading cause of death in the United States, according to the American Heart Association (AHA). As knowledge has grown, so, too, have the tools and methods for determining your risk of ASCVD, which results from the buildup of lipids, inflammatory cells, and plaque in your arteries.
Among these methods is the CT scan, which can provide a CAC score to help you better assess your risk of ASCVD.
The score measures calcified plaque in your heart's arteries.
A calcium score of zero indicates no calcium seen, while scores over 400 can signal extensive plaque and high risk.
Why are more people getting these scores now?
“A calcium score is best for intermediate-risk people who do not have any heart-related symptoms or concerns like chest pain or shortness of breath with activities, and they want personalized risk information. This information can then be used to help determine what is needed to prevent future heart attacks or strokes,” says Dartmouth Hitchcock Clinics Manchester Cardiologist Kalyan Ghanta, MD.
Those people are usually over 40 years old, but Ghanta’s colleague, Associate Medical Director Joohahn John Kim, MD, says the test is also now being used for some younger people as a diagnostic tool to develop a long-term prevention plan if they are high-risk. Kim himself sometimes uses these scores in his primary care practice when developing a risk-prevention plan, often together with the onsite cardiology team.
Cardiologist Teimuraz Apridonidze, MD, FCACC, explains one reason why.
“It is a way to detect silent coronary atherosclerosis before symptoms occur. The scan is quick, requires no IV contrast, and typically uses low radiation,” Apridonidze says.
But there are other reasons for the rise in CACs, too.
One is a greater awareness that such tests exist, particularly given people’s continued reluctance to go on statins. Statins are a class of prescription medications that can lower LDL ("bad") cholesterol while lowering cardiovascular risk, making them often a first-line therapy to reduce the chances of ASCVD.
According to a 2019 survey of almost 5,700 adults who had been recommended statin therapy, a quarter were not taking any kind of statin. Of this group, 10% declined a statin, and 30% started a stain before discontinuing it, largely due to concerns about side effects.
If you are reluctant to start statins, a CAC score can help you decide whether you should.
“Maybe you don't want to take a statin, and then you use the calcium testing, and it might be on the border, but the tie goes to the runner, that kind of justifies starting a statin,” says Kim.
Kim, Ghanta, and Apridonidze are largely supporters of going on statins, and Ghanta notes that a high calcium score—which can drop with statin medication—can mean people better understand the importance of staying on their statin, which results in less progression of atherosclerosis and less plaque growth.
The doctors also point to the low cost and relatively low risk of side effects, as reported by studies such as this one in The Lancet, which says statins are uncommonly associated with side effects.
If you do go on statins and experience side effects, your doctor might also be able to adjust the type of statin and the dosage.
So, could you benefit?
In thinking about whether to recommend a patient for a CAC, Ghanta thinks about the criteria earlier listed, namely:
- You’re between 40-75.
- You have heart-disease risk factors, like high blood pressure and high cholesterol levels, diabetes, smoking, and a family history of heart disease.
- You are unsure if you need preventive medicine like statins and low-dose aspirin*, and you don’t already have symptoms or a diagnosed heart condition.
Apridonidze adds, “It can also be helpful when risk seems ‘underestimated’ based on standard labs/history alone, or when someone has risk enhancers, like family history and metabolic risk, and wants a more individualized estimate.”
As Kim notes, a calcium score can be beneficial for some under 40 years old, too, including those with a strong premature family history of ASCVD, familial hypercholesterolemia (FH)—a common genetic disorder causing extremely high LDL, and those who receive radiation treatment, particularly for the thorax in Hodgkin lymphoma.
“We're now looking at patients at a younger age and trying to predict not only their 10-year risk, but also their 30-year risk and maybe even their lifetime risk, not only because we have new tools to treat heart disease, but we also have a lot of new emerging testing that we could do. Testing for calcium is one of those,” explains Kim.
But patients under 40 don’t usually get a calcium score because they want a clearer indicator of whether to start statins.
That’s because statins are not commonly recommended for people aged 20 to 39 years old unless they are very high-risk people with very high cholesterol levels, such as patients who have FH.
For most people in this age group, the American College of Cardiology (ACC) and AHA’s cholesterol management guidelines stress the importance of intensive lifestyle efforts over statins in lowering ASCVD risks.
But Kim also predicts that as more focus is placed on prevention in primary care through measures such as the AHA’s PREVENT (Predicting Risk of Cardiovascular Disease Events) online calculator, the use of supplementary tests, such as CAC, may increase over time among those aged 30 and older.
If you’re on the fence, why not just get a calcium score?
There are drawbacks.
The cost is often not covered by insurers and usually runs anywhere between $100 to $300 out of pocket.
Though relatively negligible, the test also requires some radiation.
If you are already at risk and over 40, the test also may not be worthwhile, given the proven effectiveness of statins and their relatively few side effects.
On top of that, many cardiologists want to see a score of zero. While more than 90% of people under 40 will get a score of zero, the likelihood of such a score decreases as you age.
“And there is a big difference between zero and one,” says Ghanta. “A score of one does not mean that you're at low risk. The atherosclerosis has started, and preventive measures should be intensified.”
Are there other tests you can take to determine your risk of heart disease?
A calcium score is just one method that cardiologists now employ to help determine your risk of ASCVD.
A blood test can measure whether you have elevated Apolipoprotein B (apoB), which attaches to harmful lipoproteins like LDL. Measuring it can help doctors get a clearer picture of your cholesterol levels.
Another measure is a mammogram.
“Research suggests BAC (breast arterial calcification) is associated with higher risk of future cardiovascular disease and may help identify risk in some women, but again, it is not yet a substitute for coronary calcium scoring and is not currently used as the primary decision tool in ACC/AHA risk algorithms,“ explains Apridonidze.
More robust, says Apridonidze, is a lung screening CAT scan (LDCT). “In our practice, we are considering using lung screening CAT scans, which is already done in long-time former or current smokers to identify patients with subclinical coronary artery disease,” he says.
But these tests are often not stand-alone and instead part of a larger analysis of individual risk done in conjunction with other measures.
If, for example, you get a high calcium score of 300 or more, you might need a stress test because even though you may not be symptomatic, you may need other interventions, says Ghanta. And these doctors also stress that no matter the test, the end goal remains developing a plan to reduce your risk of ASCVD.
Other treatments
Also important to bear in mind is that treatment is not one-size-fits-all.
For example, if you are averse to statins but your LDL level alone has indicated you may need to start statins, some find a vegan diet can help lower LDL and even bring down your calcium score, especially when done in conjunction with exercise and lifestyle modifications.
And while statins are usually considered the first line of defense, other medications exist.
“There are so many new drugs that are available,” says Ghanta.
These include PCSK9 inhibitors, such as Repatha (evolocumab), which is an injectable prescription medicine used to lower very high LDL cholesterol.
In the distant future, there is even the prospect of gene editing, but research there is very early-stage.
So should you get a calcium score to determine your ASCVD risk, especially if you have an elevated LDL?
To get an answer to that question, first consult your doctor.
And remember: A CAC score is just a piece in the puzzle when determining cardiac risk.
*A doctor may recommend low-dose aspirin to people aged 40 - 59 years old with a high risk of heart attack in the next 10 years or to people who have never had a heart attack but have had coronary artery bypass graft surgery or a stent in their artery.
