The Heart Attack Nobody Expected
We have all heard stories about someone who seemed perfectly healthy until they suddenly suffered a heart attack.
Perhaps it was a 43-year-old man who exercised regularly, maintained a reasonable weight, and had no obvious symptoms. Or a woman in her early fifties who had never been told she was at significant cardiovascular risk.
Friends and family are shocked. How could this happen? Weren't they healthy?
The uncomfortable answer is that coronary artery disease can develop silently for years, sometimes decades, before producing recognizable symptoms.
And while we have become quite sophisticated at estimating cardiovascular risk, estimating risk is not the same as identifying evidence of disease that may already be present.
That distinction raises an interesting question.
What if a relatively inexpensive, noninvasive test could tell us something important about coronary artery disease that conventional risk assessments may have missed?
And what if many people have never even heard of it?
A Heart Scan That May Cost About $100
The test is called a coronary artery calcium scan, commonly abbreviated CAC.
It is a specialized computed tomography (CT) examination that detects calcium deposits within atherosclerotic plaque in the coronary arteries, the blood vessels that supply the heart muscle.
The examination is very quick (less than 5 minutes), requires no intravenous contrast or catheter, and exposes the patient to a small amount of radiation. A single scan exposes a patient to approximately 1.0 mSv (millisieverts). For comparison, we are routinely exposed to approximately 3.0 mSv per year from natural sources and a mammogram exposes women to 0.4 mSv each test. So, considering the potential upside of detecting calcified coronary plaque in your coronary arteries a baseline CAC with any repeat testing considered individually with your clinician might be a really good idea. [3]
Unfortunately, for some reason most health plans do not cover this test. The good news, is that in some communities, the out-of-pocket price is approximately $100, although costs vary by facility, region, and insurance coverage.
The result is a coronary calcium score, often called an Agatston score.
A score of zero means no coronary calcium was detected. That is generally very reassuring, although it does not rule out noncalcified plaque or guarantee that a future cardiovascular event will not occur. Although, a zero score can also completely alter your risk estimation.
A positive score indicates that calcified coronary atherosclerosis is present. Higher scores generally indicate greater calcified plaque burden and higher cardiovascular risk. These scores can also be enlightening and alter your risk estimation in another direction. The important point is these scores change clinical conversation from estimating risk to measuring current disease state and improving risk estimation.
Importantly, the interpretation also depends on age, sex, and the patient's broader clinical picture.
Consider two asymptomatic people, the same age, and sex, with similar cholesterol values, blood pressure, and other conventional risk factors, such as weight, glucose levels and fitness.
One has a CAC score of zero.
The other has a score of 175.
ILLUSTRATIVE COMPARISON
Same risk factors. Different coronary plaque.
Comparable age, sex, cholesterol and blood pressure
No detectable coronary calcium.
Calcified coronary plaque detected.
Similar risk factors do not always mean similar coronary plaque burden.
Would you expect their preventive-health conversations to be identical?
Probably not.
And that is precisely why this test deserves more attention.
What MESA Taught Us About Cardiovascular Risk
The Multi-Ethnic Study of Atherosclerosis, better known as MESA, has contributed enormously to our understanding of cardiovascular risk.
MESA followed adults without known clinical cardiovascular disease and examined how different measurements, including coronary artery calcium, relate to subsequent cardiovascular events.
In a landmark analysis published in JAMA in 2010, researchers evaluated 5,878 participants to determine whether adding CAC to conventional risk factors improved the classification of coronary heart disease risk. [1]
The results were striking.
Approximately 26% of participants changed risk categories when CAC was included. [1]
Some were reclassified upward, indicating greater estimated risk than conventional factors alone suggested. Others were reclassified downward.
In other words, adding information about calcified coronary plaque materially changed the interpretation for more than one in four participants. That can change clinical decisions and conversations.
But the researchers found something else worth considering.
Adding CAC also improved the ability of risk models to distinguish people who would subsequently experience coronary events from those who would not. In a subsequent 10-year CHD prediction analysis in MESA, the C-statistic, a measure of predictive discrimination, improved from approximately 0.75 to 0.80 when CAC was incorporated into traditional risk assessment. [2]
That may look like a small numerical difference, but it represents a meaningful improvement in cardiovascular risk prediction.
And the implications can be even more striking for an individual patient.
Consider an example presented by MESA researchers: a 70-year-old Hispanic man with mild treated hypertension and no other traditional risk factors had an estimated 9.3% risk of coronary heart disease over the next 10 years. When a CAC score of zero was incorporated, his estimated risk fell to 3.1%. [2]
A PUBLISHED MODEL EXAMPLE
What changed when CAC was added?
Same patient’s estimated 10-year coronary heart disease risk
Same patient. Same risk factors. More information.
The patient didn't change. His blood pressure didn't change. His cholesterol didn't change. What changed was the information available to estimate his risk.
That is not a reduction in actual risk caused by undergoing a scan. It is a change in the estimated risk once additional information became available.
Think about what that could mean for someone considering a medication they may be expected to take for the rest of their life.
And CAC can change the conversation in the opposite direction, too. Someone whose conventional risk factors appear relatively reassuring may discover substantial calcified coronary plaque, suggesting greater risk than previously recognized.
That does not mean everyone who changes risk categories has dangerous coronary blockages. Nor does a CAC score of zero guarantee that an event will not occur.
But it demonstrates something important: conventional risk factors do not always tell the complete story.
We can estimate the probability that someone will experience a coronary event based on age, cholesterol, blood pressure, smoking, diabetes, and other variables.
CAC provides additional, and fundamentally different, information.
It can tell us whether calcified coronary atherosclerosis is already detectable.
For someone whose estimated risk and actual plaque burden point in different directions, that information may substantially change the clinical conversation.
READING THE SCORE
How CAC scores are commonly described
Before a Long-Term Prescription, Shouldn't We Have a Better Conversation?
Consider an asymptomatic adult who is advised to begin statin therapy because their cholesterol or calculated cardiovascular risk exceeds a recommended threshold.
Statins have demonstrated small cardiovascular benefits when used in primary prevention patients. These are patients without known disease. They can reduce the likelihood of cardiovascular events, particularly in people at higher baseline risk. The reality is in a high-risk population using statins for primary prevention many studies have shown the absolute risk reduction is less than 2%. [5]
Statins also have very real and potential adverse effects, and the expected absolute benefit is not identical for every patient.
For some individuals, the anticipated benefit is more substantial. These are the patients with known disease. For others, particularly in primary prevention at lower estimated risk, the absolute benefit may be more modest.
These distinctions matter when discussing treatment that could continue for decades.
Yet some patients describe feeling pressured to accept a prescription without fully understanding their individual risk, the likely absolute benefit, potential adverse effects, or reasonable alternatives. While many providers will paint a picture that statins have little to no side-effects while insisting the benefit will be profound the truth is far different.
Some patients worry that questioning the recommendation will cause them to be labeled noncompliant. I know this for a fact and can provide testimonials of patients being released from provider care for just this reason. I can also verify that when some informed patients have asked for a CAC prior to considering statin therapy to enhance the conversation with more information their providers insist it will provide no further value. This is false.
Is that really how informed consent and shared decision-making should work?
A patient who asks questions is not necessarily rejecting medical advice. They may simply be trying to understand it.
Now consider the role CAC could play in an appropriate primary-prevention patient.
A CAC score of zero may support postponing statin treatment in some individuals while continuing to address modifiable risk factors. In contrast, substantial coronary calcium may strengthen the rationale for preventive medication, even when conventional laboratory results appear relatively reassuring. Neither result should be interpreted in isolation. [4]
For example, a zero score does not erase the significance of diabetes, cigarette smoking, a strong family history of premature coronary disease (first-degree male relatives <55 years and females <65 years), or other important clinical circumstances. And someone with established cardiovascular disease generally does not need CAC to justify secondary-prevention treatment. [4]
But for patients in whom the treatment decision remains uncertain, wouldn't it be reasonable to ask:
“Before I commit to long-term medication, would a coronary calcium scan help us better understand my cardiovascular risk? And if not, why not?”
That is not an argument against statins. It is an argument for informed decisions.
Is a $100 Baseline Worth Considering?
In Health Ballistics, I raised the possibility of discussing baseline CAC testing around age 40 for men and age 50 for women.
Why those ages?
Because atherosclerosis often begins long before symptoms develop, and conventional short-term risk calculations can make younger adults appear reassuringly low risk, even when important risk factors are present.
Consider a 42-year-old man whose father experienced a myocardial infarction at age 46. This person does indeed have risk due to first-degree relative with premature disease. Sure, he feels healthy. His routine laboratory results are not particularly alarming. His calculated 10-year risk may be low, partly because of his age. Would a CAC scan provide information that changes the discussion? Possibly.
Family history of premature coronary disease is an important risk-enhancing factor. A positive CAC score in a relatively young adult can be especially meaningful because calcified coronary plaque is less common at younger ages.
The absence of detectable calcium, however, does not eliminate inherited risk or exclude noncalcified plaque.
Current cardiovascular guidelines recognize CAC as a useful tool for selected adults when additional information could clarify preventive treatment decisions. [4]
That is not the same as recommending universal screening at a particular birthday.
But perhaps we should distinguish two questions:
Should every asymptomatic adult automatically receive a CAC scan?
And:
Should more adults entering middle age be informed about CAC and offered a discussion about whether it would be useful?
Those are very different propositions. The second seems particularly worthy of consideration. But considering the option of life-long pharmacological therapy prior to a scan does the first scenario really present serious downsides? A scan at some point will certainly establish a baseline which often provides additional context in the future.
What If You Want to Try Lifestyle Intervention First?
Suppose someone is willing to improve nutrition, exercise regularly, reduce excess body fat, improve blood pressure and glucose regulation, and reassess their cardiovascular risk before beginning long-term medication. Would knowing their CAC score be helpful? I can assure you, in many circumstances, yes.
Evidence of substantial coronary calcium might suggest that a lifestyle-only approach is not sufficient to address their overall risk and that medication deserves serious consideration alongside lifestyle intervention.
Conversely, a zero score might support a different discussion in a suitably selected patient.
But there is an important limitation. CAC is primarily a tool for risk assessment, not a short-term measure of whether a lifestyle intervention is working. Calcified plaque may not disappear when someone improves their metabolic health. Calcium scores can even increase during effective preventive treatment, including statin therapy, without necessarily indicating that treatment is failing. [6]
Therefore, repeating CAC scans over short intervals is not an established method for measuring lifestyle success.
We should continue to evaluate the response to intervention through appropriate clinical measures: blood pressure, glucose regulation, lipids, body composition, cardiorespiratory fitness, and other relevant markers.
The baseline CAC result may help clarify the starting risk. Ongoing assessment helps determine how the person is responding. Hopefully, it will verify progression has slowed.
Both can contribute useful information, but they answer different questions.
What Are the Downsides?
No screening test is perfect, and CAC is no exception.
The examination involves ionizing radiation, although the dose is generally low. In rare cases, it may identify incidental findings that lead to additional testing, expense, or anxiety.
CAC detects calcified plaque, not all coronary plaque. A score of zero is quite reassuring in many circumstances but does not guarantee that coronary disease is completely absent.
A positive score also does not reveal whether a particular plaque is likely to rupture or whether a coronary artery has a flow-limiting blockage.
Nor does a positive CAC result automatically justify a stress test, coronary angiogram, or stent.
PUTTING THE RESULT IN CONTEXT
What CAC tells you and what it doesn’t
CAC can help reveal
- Detectable calcified coronary plaque
- Relative calcified plaque burden
- Information that may refine estimated future risk
CAC cannot establish
- Absence of noncalcified plaque
- Whether a specific lesion will rupture
- Whether an artery has a flow-limiting stenosis
- Whether a scan itself prevents future events
A useful piece of information, not the entire cardiovascular picture.
Most importantly, while CAC improves cardiovascular risk classification, evidence that routinely screening all asymptomatic adults reduces myocardial infarctions or deaths remains insufficient. These limitations deserve to be explained. But they also invite a reasonable question. [7]
When the cost and procedural risks are relatively modest, and the information may change an important preventive decision, shouldn't we be more willing to discuss whether the test is appropriate?
A Question for Self-Funded Employers
Cardiovascular disease remains the leading cause of death in the United States and worldwide. It also represents a substantial burden for employers through healthcare claims, hospitalization, disability, absenteeism, and lost productivity.
Self-funded employers have a particularly direct financial interest in the health of their workforce. Many already invest in biometric screenings, wellness programs, risk assessments, and chronic disease management. But consider what those programs actually measure.
Are they primarily identifying risk factors? Are they helping employees and their clinicians understand whether cardiovascular disease may already be developing? Are they connecting risk assessment to appropriate preventive action?
And here is another question:
Does your employee health plan make coronary artery calcium testing accessible when clinically appropriate?
If adding a relatively inexpensive test can materially improve cardiovascular risk classification, shouldn't employers at least examine whether their preventive-health programs are using the information available to make better decisions? If not, why not? If it does, how many employees know that this option exists, or understand when it might be useful?
We routinely pay for the consequences of cardiovascular disease: emergency care, hospitalization, coronary interventions, long-term treatment, and sometimes permanent disability.
Would it be worthwhile to examine whether relatively inexpensive, appropriately targeted CAC testing could improve preventive decision-making before a serious event occurs? Could identifying previously unrecognized coronary atherosclerosis lead to better-targeted treatment? Could that, in turn, help reduce some future myocardial infarctions, emergency interventions, or cardiovascular deaths?
These are important questions, not promises of savings or guaranteed outcomes. Improved risk classification does not automatically establish that a screening program will reduce events or healthcare spending. But employers should be willing to ask them.
A prevention program should ultimately be evaluated by more than participation rates and the number of tests performed.
We should also be interested in whether employees receive useful information, make better-informed decisions, and experience meaningful improvements in health.
The Questions Worth Asking
If you are an individual, consider:
Did you know a coronary artery calcium scan existed?
Has your physician ever discussed whether it would be appropriate for you?
Do you have a family history or other risk factors that might make additional assessment useful?
If you are considering long-term preventive medication (statins), could CAC information change the discussion?
Did your physician tell you about CAC scans prior to prescribing statin drugs?
Do you understand what a positive score, or a score of zero, would and would not mean?
If you are a self-funded employer or benefits adviser, consider:
Is CAC testing accessible to employees for whom it is clinically appropriate?
Are employees informed about this option?
Does your preventive-health strategy help translate risk assessment into meaningful clinical decisions?
Are you evaluating whether your healthcare investments improve actual health outcomes?
You know your cholesterol. You know your blood pressure. But do you know whether you already have coronary plaque?
A coronary calcium scan cannot predict every heart attack. It cannot detect every form of coronary plaque. And it is not the right test for everyone.
But when a relatively inexpensive, noninvasive examination can identify previously unrecognized calcified coronary atherosclerosis, and sometimes materially change how we understand cardiovascular risk, shouldn't more people know it exists?
Perhaps the $100 question isn't whether everyone should have a coronary calcium scan. It's why so many people have never been invited to discuss whether one could help them.
This article is intended for education and informed discussion, not individual medical advice. Decisions about CAC imaging, preventive medication, and cardiovascular risk management should be made with a qualified clinician in the context of the individual's full medical history and risk profile.
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References
- Polonsky TS, et al. Coronary artery calcium score and risk classification for coronary heart disease prediction. JAMA. 2010;303(16):1610–1616. doi:10.1001/jama.2010.461.
- McClelland RL, et al. 10-Year Coronary Heart Disease Risk Prediction Using Coronary Artery Calcium and Traditional Risk Factors: Derivation in the MESA Cohort With Validation in the HNR Study and the DHS. J Am Coll Cardiol. 2015;66(15):1643–1653. doi:10.1016/j.jacc.2015.08.035.
- Messenger B, et al. Coronary calcium scans and radiation exposure in the multi-ethnic study of atherosclerosis. Int J Cardiovasc Imaging. 2016;32(3):525–529. Study record. Also see ACR/RSNA radiation-dose comparisons; doses vary by protocol.
- 2026 ACC/AHA multisociety guideline on the management of dyslipidemia. Full guideline. Selective CAC use and treatment decisions require clinical context.
- Chou R, et al. Statin use for the primary prevention of cardiovascular disease in adults: updated evidence report and systematic review for the US Preventive Services Task Force. JAMA. 2022;328(8):754–771. Study record. Absolute effects depend on endpoint, baseline risk and follow-up.
- van Rosendael AR, et al. Association of statin treatment with progression of coronary atherosclerotic plaque composition. JAMA Cardiol. 2021;6(11):1257–1266. Study.
- US Preventive Services Task Force. Risk assessment for cardiovascular disease with nontraditional risk factors. 2018. Recommendation and evidence.
