The Hundred-Dollar Look at Your Death

The coronary artery calcium score — the $100–150 test that shows you your vascular age

There is a test that takes twelve minutes, involves no contrast, no needles, no preparation, and costs between one hundred and one hundred fifty dollars out of pocket at most imaging centers in the United States. It uses a low-dose CT scanner to measure the amount of calcium deposited in the walls of the coronary arteries — the arteries that supply blood to the heart muscle. It produces a single number, expressed in Agatston units, that represents the cumulative calcified atherosclerotic plaque burden in those arteries. A score of zero, in a man under fifty-five with no other significant risk factors, is the most reassuring cardiovascular finding a cardiologist can offer — the kind of finding I deliver to patients with genuine satisfaction, because it genuinely changes the risk conversation. A score of four hundred or above — which I have seen in men who exercise regularly, eat carefully, have never smoked, and were told at their last physical that everything looked fine — is associated with a mortality and major adverse cardiovascular event risk so elevated that cardiologists now treat it with the same management intensity we would apply to someone who has already had a heart attack.

I order this test for every appropriate patient who has the access and the resources for it. I have sat across from men who learned things from their CAC score that changed how they approached the next decade of their lives. I have also watched men decline the test because they were afraid of what it might show — and I have had some of those conversations turn out to be much harder, later, than they needed to be.

This chapter is about what the coronary artery calcium score is, what it means at every level of the scale, why it is one of the most powerful risk stratification tools in preventive cardiology, and specifically what you should do with the result.

What the CAC Score Is and Is Not

The coronary artery calcium score quantifies the calcified component of atherosclerotic plaque in the coronary arteries. This is an important distinction to make precisely, because there is a common misunderstanding about what a high CAC score means.

Atherosclerotic plaque — the buildup that eventually causes heart attacks and coronary artery disease — exists in two forms: non-calcified (soft) plaque, which is lipid-rich and inflammatory and is actually more acutely dangerous because it is more prone to rupture, and calcified plaque, which represents older, more stable plaque that the body has attempted to harden with calcium deposits. The CAC score measures only the calcified component.

This means two things. First, a CAC score is not a measure of arterial obstruction. A man can have a CAC score of 350 — indicating significant atherosclerotic plaque burden — with no arteries that are significantly obstructed. His stress test would likely be negative. His symptoms might be minimal or absent. The calcium is not blocking the arteries; it is evidence of years of plaque accumulation in the arterial walls, some of which may be soft and unstable underneath a calcified cap. This is why men with high CAC scores and negative stress tests are not cleared — they are reclassified.

Second, a CAC score of zero does not guarantee the complete absence of coronary atherosclerosis. Non-calcified soft plaque can be present even when the calcium score is zero, particularly in younger men with shorter duration of atherogenic exposure. This is relevant when interpreting newer AI-enhanced CCTA imaging technologies that go beyond calcium scoring — but for population-level preventive cardiology, the CAC score remains the most validated and widely available non-invasive risk stratification tool, and a CAC of zero in an appropriately selected patient carries genuinely low event rates over ten-year follow-up.

What the CAC score is, definitively, is a direct anatomical measure of accumulated atherosclerotic burden in the coronary arteries. It is the most specific imaging evidence of whether the vascular damage predicted by ApoB, blood pressure, metabolic syndrome, and the upstream chain has actually materialized in the coronary artery walls. It is the difference between statistical risk and anatomical reality.

The Score Categories and What They Mean

The Agatston unit scale used for CAC scoring has established clinical threshold categories that have been validated across large prospective cohort studies. Here is what each category means in clinical practice:

CAC = 0: No calcified coronary artery plaque is detectable. In a man aged forty to fifty-five with no other high-risk features, this confers a ten-year major cardiovascular event risk of less than one percent and is associated with what researchers call a “warranty period” — the estimated interval over which this finding remains reassuring — of approximately ten years in younger patients and slightly shorter in older or higher-risk individuals. A zero score is not a permanent green light; it is a powerful reassurance with a time limit. I tell patients with a CAC of zero: “This is the best cardiovascular imaging finding I can give you. Come back in five to seven years if your risk factors haven’t changed substantially.”

CAC 1–100: Minimal to mild calcified plaque is present. This finding confirms that atherosclerosis is underway, but the burden is modest. In the Multi-Ethnic Study of Atherosclerosis — the MESA study, which I’ll discuss in detail shortly — even a score of one to ten was associated with a hazard ratio of 3.66 for coronary heart disease events compared to a score of zero, after full adjustment for traditional risk factors. This is not a mild risk increment. The clinical implication is that lifestyle intervention and pharmacological management (typically statins) should be seriously considered, with the decision calibrated to the full clinical picture.

CAC 101–400: Moderate calcified plaque burden. This range represents well-established atherosclerosis. Men in this range have a ten-year ASCVD event risk that typically exceeds seven and a half percent — the threshold at which current American Heart Association guidelines recommend statin therapy in most patients, regardless of LDL-C level. A CAC in this range overrides a borderline Framingham risk score. The man who was classified as “intermediate risk” by traditional risk calculators and has a CAC of 180 is no longer intermediate risk.

CAC > 400: Extensive calcified plaque burden. The cardiovascular risk conferred by this score is severe. A 2025 retrospective analysis by Rao and colleagues indexed in PubMed found that a CAC score of 400 or above was associated with a 4.76-fold higher risk of mortality or major adverse cardiovascular events compared to a score of zero. In the MESA cohort data — one of the largest and most rigorous CAC outcome datasets available — CAC above 400 carried hazard ratios for coronary events approaching twenty compared to CAC zero. These are not statistical curiosities. They are the numbers that change my clinical approach immediately and completely. A man with a CAC of 600 who has not been on statin therapy, whose blood pressure is uncontrolled, and who is not seeing a cardiologist is in a situation I am not comfortable with, regardless of his LDL-C or his Framingham Risk Score.

The MESA Study: The Evidence Foundation

The Multi-Ethnic Study of Atherosclerosis — MESA — is the single most important epidemiological study for understanding coronary artery calcium scoring in the real-world population. It enrolled 6,814 men and women aged forty-five to eighty-four from six US cities in 2000, representing four racial and ethnic groups, and has followed them prospectively for over fifteen years. The dataset is one of the most rigorously assembled in modern cardiology.

A foundational MESA analysis published in the New England Journal of Medicine in 2008 by Detrano and colleagues established the core CAC risk prediction relationships across racial and ethnic groups: CAC was the single strongest predictor of incident coronary events, substantially outperforming traditional risk factors including age, LDL-C, blood pressure, smoking, and diabetes in reclassifying risk. For men in the highest CAC category — above 300 Agatston units — the hazard ratio for coronary events was 7.73 compared to men with a score of zero.

What MESA also demonstrated, powerfully, is that CAC reclassifies risk in a clinically actionable way. Men classified as “intermediate risk” by Framingham score — the risk category where clinical decision-making is most uncertain and where physicians and patients face the greatest ambiguity about whether to start treatment — were reclassified by CAC to either low risk (score zero, treatment deferral appropriate) or high risk (score above 100, treatment clearly warranted) in a substantial proportion of cases. This reclassification changes clinical conversations, changes prescribing decisions, and in the evidence base, changes outcomes.

The 2016 analysis of fifteen-year MESA data by Blaha and colleagues provided the longest follow-up data: CAC scoring predicted all-cause mortality over fifteen years with consistent power, and the zero-score warranty period was validated as extending through at least ten years for most risk groups.

The Reclassification Power

The concept of reclassification is worth dwelling on, because it is the core clinical argument for CAC scoring in intermediate-risk men — which is to say, in most of the men reading this book.

The standard cardiovascular risk calculators — the Pooled Cohort Equations used in current American College of Cardiology and American Heart Association guidelines, and the older Framingham Risk Score — estimate ten-year ASCVD risk based on age, sex, race, cholesterol, blood pressure, smoking status, and diabetes. These calculators are useful population-level tools but they have well-documented limitations at the individual level: they can misclassify up to thirty percent of intermediate-risk individuals as either higher or lower risk than their actual biology warrants.

The intermediate risk category — approximately seven to twenty percent ten-year ASCVD risk — is clinically the most challenging because it is the category where statin therapy is a decision rather than an obvious recommendation. The threshold for statins in current US guidelines is a ten-year risk of seven and a half percent or above, at which point the evidence clearly supports treatment in most patients. But the man with a calculated ten-year risk of nine percent sits in a zone of clinical ambiguity: the guideline recommendation exists, but the shared decision conversation is genuinely complex, particularly for patients who are hesitant about starting lifelong medication.

CAC scoring resolves much of this ambiguity directly. A 2014 analysis published in JAMA by Yeboah and colleagues from MESA compared CAC scoring with other candidate risk markers — ankle-brachial index, carotid intima-media thickness, high-sensitivity CRP, and family history — in improving risk classification in intermediate-risk individuals. CAC scoring provided the largest and most consistent improvement in net reclassification, moving a substantial proportion of intermediate-risk patients into the low-risk category (where treatment could be deferred) and another proportion into the high-risk category (where treatment was clearly warranted). The man with a calculated ten-year risk of nine percent and a CAC score of zero can have a different conversation about statins than the man with the same calculated risk and a CAC of 210.

The Zero Score: Genuine Reassurance

I want to spend time on the zero score because it is an important finding that I don’t want to discount in a chapter focused primarily on the high scores. A CAC of zero is not a minor finding. It is clinically powerful.

In a man between forty and fifty-five with no high-risk features — no established cardiovascular disease, no diabetes with complications, no very high LDL-C, no severely elevated blood pressure — a CAC score of zero provides approximately ten years of cardiovascular reassurance that goes beyond what any blood test can provide. It tells you, directly and anatomically, that your coronary arteries have not accumulated significant calcified plaque. The statistical risk of a major cardiovascular event over the subsequent decade is less than one percent in this group.

This finding changes conversations about statin therapy specifically. Many men in the intermediate risk category who are ambivalent about statins — because of cost, side effect concern, philosophical preference for lifestyle modification, or any number of legitimate reasons — and who obtain a CAC score of zero can, in clinical consultation with their physician, reasonably defer statin initiation while focusing intensely on lifestyle interventions and reassessment. The zero score is the anatomical justification for a different approach.

The important caveat: the zero score applies to calcified plaque. In men with markedly elevated ApoB, elevated Lp(a), or other high-risk features, non-calcified soft plaque may be present even with a CAC of zero, and the clinical conversation is correspondingly more nuanced. For this reason, the ACC/AHA 2018 guidelines specify that in men with known very high Lp(a) or familial hypercholesterolemia, the zero score provides less reassurance than in the general intermediate-risk population.

Who Should Get a CAC Score

The 2018 AHA/ACC Blood Cholesterol Guidelines include CAC scoring as the preferred approach for resolving clinical uncertainty about statin therapy in men and women between forty and seventy-five who are at intermediate cardiovascular risk and who have not already been established on treatment for a prior cardiac event.

More specifically, the clinical profile that most warrants CAC scoring is:

• Male, age forty to seventy-five
• No established cardiovascular disease
• LDL-C between 70 and 190 mg/dL (outside the range where treatment is automatic)
• Estimated ten-year ASCVD risk between five and twenty percent
• Any uncertainty about whether the clinical risk estimate is accurate for this specific individual

The man who is forty-seven, has an LDL-C of 115 mg/dL, a blood pressure of 132/84, and a ten-year risk calculation of eight percent is the prototypical CAC candidate. So is the man who is fifty-two, has a family history of premature coronary artery disease, and wants to know whether his own arteries have been affected — regardless of his calculated risk.

The men for whom CAC scoring adds less value are those at either extreme: the forty-five-year-old with no risk factors whatsoever whose pre-test probability of significant CAC is very low, and the sixty-two-year-old with established hypertension, diabetes, and a previous stroke who already has unambiguous indications for aggressive treatment regardless of CAC.

The Princeton IV Consensus (2024), which establishes the most current guidelines for cardiovascular risk management in men with erectile dysfunction, is worth noting here specifically: men with vasculogenic ED who are otherwise at low to intermediate ten-year ASCVD risk are specifically recommended for CAC scoring as part of advanced risk stratification. This is a direct acknowledgment that the vascular warning signal of ED warrants looking at the coronary arteries directly, not relying on a statistical risk score.

CAC and the PESA Data: Subclinical Atherosclerosis Is Shockingly Common

One of the most important epidemiological revelations in preventive cardiology in the last decade came from a study conducted on the most unlikely subjects: healthy, employed, middle-aged Spanish bank workers.

The Progression of Early Subclinical Atherosclerosis study — PESA — enrolled approximately four thousand asymptomatic employees of Banco Santander in Spain between the ages of forty and fifty-four and subjected them to comprehensive vascular imaging: coronary artery calcium scoring, carotid and femoral artery ultrasound, and aortic imaging. These were not high-risk patients. They were working professionals in good apparent health, with no known cardiovascular disease. The average age was forty-five.

The findings were striking enough that Fernández-Friera and colleagues published them in the Journal of the American College of Cardiology in 2017: sixty-three percent of participants had evidence of subclinical atherosclerosis on at least one imaging modality. Forty-two percent had multiterritorial disease — plaque in more than one vascular territory simultaneously. Among participants with LDL-C in the “normal” range — below 130 mg/dL — subclinical atherosclerosis was still present in over fifty percent. ApoB was a stronger predictor of subclinical disease than LDL-C in this cohort.

The clinical implication is uncomfortable: the man who looks around his workplace and assumes that the majority of his age-matched colleagues are cardiovascularly clean is wrong. Six out of ten of those colleagues have measurable atherosclerosis if you look for it directly. Most of it is silent. Most of it will not produce symptoms for years or decades. Some of it will produce a cardiac event without any warning. The absence of symptoms is not the absence of disease. It is the absence of measurement.

CAC scoring is one of the few tools available in clinical practice that turns this population-level statistic into an individual finding. The PESA study cannot tell you whether you personally are in the sixty-three percent. A CAC scan can.

The Non-Calcified Plaque Consideration

I want to address one important limitation of the coronary artery calcium score that has become more clinically relevant as newer imaging technologies have become available, because it changes how I frame the zero score in certain patients.

CAC scoring measures calcified plaque — the older, more stable, more rigid deposits of calcium in the coronary arterial wall. It does not measure non-calcified, or “soft,” plaque — the lipid-rich, inflammatory, cholesterol-laden deposits that are actually more prone to rupture and more immediately dangerous. Most heart attacks are caused by rupture of soft, non-calcified plaque, not by calcified plaque. A significant proportion of men who present with acute myocardial infarction have low or even zero CAC scores, because their vulnerable plaque has not yet calcified.

This is not a reason to dismiss the CAC score’s value — it remains the most validated non-invasive cardiovascular imaging tool in preventive practice, with an unrivaled evidence base for outcome prediction. It is a reason to understand its specific limitation: it measures the legacy of long-term atherogenic exposure that has calcified, not the acutely dangerous soft plaque that may be present in younger men with shorter durations of atherogenic exposure but high-risk metabolic profiles.

Emerging technologies, specifically AI-enhanced coronary CT angiography platforms like Cleerly, can now quantify both calcified and non-calcified plaque burden from a single cardiac CT scan. In intermediate-risk men with elevated ApoB, elevated Lp(a), or metabolic syndrome who have zero or low CAC scores but high clinical concern for non-calcified disease, this technology provides an additional layer of anatomical intelligence. It is not yet standard of care, but the 2023 JAMA Cardiology data on Cleerly — finding high-risk non-calcified plaque in approximately thirty percent of patients not predicted by CAC score alone — is moving it rapidly in that direction.

For the purposes of this book, the practical takeaway is: a CAC score of zero in a forty-two-year-old with an ApoB of 130, a family history of premature coronary disease, and elevated Lp(a) is reassuring but not conclusive. The conversation with your cardiologist should acknowledge both the reassurance and the limitation.

The Radiation Question

I address this in every conversation about CAC scoring, because it is a legitimate question that deserves a calibrated answer.

A coronary artery calcium scan uses ionizing radiation. The effective dose is approximately one to three millisieverts — equivalent to one to three chest X-rays, and roughly a third of the average American’s annual background radiation exposure. For comparison, a mammogram delivers approximately 0.4 millisieverts; a dental X-ray approximately 0.005 millisieverts; a standard full-body CT scan approximately 10 millisieverts. The radiation exposure from a CAC scan is at the lower end of diagnostic imaging.

The relevant risk calculation is the absolute cancer risk attributable to the radiation dose versus the cardiovascular risk information gained. For a forty-five-year-old man with intermediate cardiovascular risk, the calculated lifetime excess cancer risk from a single CAC scan is approximately one in ten thousand — significantly smaller than the cardiovascular event risk the scan is evaluating. This is, by any reasonable clinical calculus, a favorable risk-benefit ratio.

The counterargument sometimes offered is that a low or zero CAC score in a younger patient may prompt rescanning every five to ten years, accumulating radiation over time. This is worth discussing with your physician, and it is a reason not to scan unnecessarily or repeatedly without clinical indication. It is not a reason to forgo the scan in a man for whom the clinical information it provides would meaningfully change management.

Reading Your Result with Your Physician

If you get a CAC scan, here is what I want you to know before you see the result.

The report will give you two numbers: the absolute Agatston score and the percentile ranking — where your score falls relative to men of your age and race. Both are clinically relevant, but they mean different things.

The absolute score is the direct measure of plaque burden. The percentile ranking tells you how your plaque burden compares to your demographic peers. A man of fifty with a CAC score of 80 is in the seventy-fifth percentile for his age — higher than most men his age, but not in the highest risk category. A man of forty-two with a CAC score of 80 is in a very high percentile for his age, because forty-two-year-olds rarely have that much calcified plaque, and the score reflects an accelerated vascular aging process that warrants immediate clinical attention.

The ACC/AHA guidelines use the absolute score for treatment decisions. The percentile ranking is additional clinical context, particularly useful for younger patients where the score-based categories may underestimate the significance of what the imaging shows relative to peers.

What to do with the result: bring it to your physician or, if you ordered it yourself, bring it to a cardiologist. The CAC score does not tell you what intervention to make; it tells you which category of interventions is warranted. A score above 100 in a man without prior treatment is a clear indication for statin therapy discussion. A score above 300 warrants aggressive lipid management, blood pressure optimization, and more frequent cardiovascular monitoring. A score above 400 warrants the same management intensity as established coronary artery disease, including potentially aspirin therapy (in consultation with your physician), which is no longer universally recommended in primary prevention but has a different calculus in high-plaque-burden patients.

Clinical Pearl — If you read nothing else in this chapter: A coronary artery calcium score of zero in a man between forty and fifty-five with no other major risk factors confers a ten-year cardiovascular event risk of less than one percent. A score above three hundred in the same man confers a risk that warrants the same clinical management intensity as a man who has already had a heart attack. This test costs one hundred to one hundred fifty dollars, requires no preparation, takes twelve minutes, and does not need to be repeated for five to seven years. The MESA study data, published in the New England Journal of Medicine by Detrano and colleagues in 2008, remains the most powerful available demonstration of this test’s prognostic power. It changes conversations in ways that lab tests alone cannot.

Victor is fifty, a corporate attorney, and describes himself as “healthy for his age.” He runs three times a week. He does not smoke and drinks moderately. His LDL-C at his last physical was 122 mg/dL. His physician told him to keep doing what he was doing. Victor’s father died of a heart attack at fifty-eight; this fact has been in the back of Victor’s mind since he turned forty-five. A colleague his age recommended this book; Victor ordered a CAC scan without quite knowing what to expect. His score was 287 Agatston units — seventy-eighth percentile for men his age. He called his physician from the parking lot of the imaging center. He is now on a statin, with an ApoB measured for the first time at 112 mg/dL, and he has had a conversation with his cardiologist that he describes as “the most important hour I’ve spent on my health in thirty years.” His father’s death no longer feels like an abstract inherited risk. It feels like a trajectory that Victor is actively choosing to alter. This is exactly what the CAC score is for.

What to Do This Week

1. Estimate your ten-year ASCVD risk using the ACC/AHA Pooled Cohort Equations calculator — available free at acc.org/tools/heart-risk-estimator. You will need your age, total cholesterol, HDL cholesterol, blood pressure, and whether you are on blood pressure medication. If your ten-year risk is between five and twenty percent, and you do not have a prior cardiac diagnosis, bring the question of CAC scoring to your physician at your next visit.

2. If you have a father or brother who had a confirmed heart attack or coronary artery bypass surgery before age sixty, put CAC scoring on your near-term clinical agenda regardless of your calculated risk score. Family history of premature coronary artery disease is one of the strongest independent indications for CAC in men under fifty-five.

3. If you already have labs showing high ApoB, elevated Lp(a), elevated fasting insulin, or uncontrolled blood pressure — any combination of risk factors that makes you suspect your vascular age is ahead of your chronological age — ask your physician this week about a referral for CAC scoring. The cost is accessible, the information is irreplaceable, and the alternative is continuing to estimate a number you could simply look at.

Transition to Chapter 8

Your coronary arteries are made of muscle, lined by endothelium, built from biochemistry. So is the endocrine system that runs in parallel with your vascular system, shaping its function from the inside out. Chapter 8 is about the hormone axis that holds everything together in the male body — and what happens to it when a man has been running on cortisol for twenty years and the biology of that running finally becomes visible in his blood, his body composition, and his daily experience of being himself.