In short
Silent cardiovascular risk means plaque in your arteries that has not caused a symptom yet. A calcium score is the single best test for finding it.
- A score of zero is the strongest reassuring result in preventive cardiology, stronger than a normal CRP, a normal carotid scan or a clean family history.
- A score of 100 or more puts you above the treatment threshold whatever your calculator said.
- The scan takes minutes, needs no contrast, no fasting and no medication, and the radiation is about the same as a mammogram.
Condition Overview
What does silent cardiovascular risk actually mean?
It means atherosclerosis that is already present but has not yet narrowed an artery enough to cause chest pain or breathlessness.
Calcium appears in the artery wall as plaque develops. A CT scan of the heart can count it, and the amount predicts events better than almost anything else available.
How good is a calcium score?
In the MESA study of 6814 people with no known heart disease, compared with a score of zero, the risk of a coronary event was 7.7 times higher with a score of 101 to 300, and 9.7 times higher above 300.
In a registry of 66,636 people, those above 1000 had markedly higher cardiovascular and all cause mortality than every lower band.
What do the numbers mean?
| 0 | No detectable plaque. The strongest reassurance available, and statins are usually not started on risk grounds alone. |
| 1 to 99 | Mild. A statin is reasonable, decided together, aiming for LDL under 70 mg/dL. |
| 100 to 299 | Moderate. Event rate at least 7.5 per cent over 10 years. Statin indicated, LDL target under 70 mg/dL. |
| 300 or more | Severe. Similar risk to people with known heart disease. LDL target under 55 mg/dL. |
Why is a score of zero such a strong result?
Because among all the markers that have been compared head to head, the absence of coronary calcium is the strongest negative risk factor. It out performs a normal CRP, a normal carotid thickness, a normal ankle brachial index, absent albuminuria and family history.
It also beat polygenic risk scores in two large population studies. In those cohorts the calcium score improved risk prediction and the genetic score did not.
Who is most likely to be reclassified?
- Women. Calculators give women lower scores. Among 6739 middle aged women at low or borderline risk, 36 per cent had some calcium, and its presence doubled the risk of events and moved 20 per cent of them into a more accurate risk category.
- Older adults. In the Rotterdam Study, calcium reclassified 52 per cent of intermediate risk adults, upward above 615 or downward below 50. It was better than age at getting the risk right.
- People at borderline or intermediate risk. This is where the score changes decisions most often.
What a calcium score cannot tell you
It is not a test for symptoms. If you have chest pain or breathlessness, a score of zero does not rule out significant disease. Between 13 and 16 per cent of people with symptoms and a score of zero have flow limiting coronary disease.
It also does not measure soft plaque directly, and repeat scanning to check whether treatment is working is not useful. Progression adds very little to what the first scan already told you.
When to See a Doctor
- You are 30 to 79, have no diagnosed heart disease, and have never had your risk formally calculated
- Your calculated 10 year risk came out borderline, 3 to under 5 per cent, and the decision on treatment is genuinely unclear
- You are at intermediate risk and hesitant about starting a statin
- A parent or sibling had a heart attack or stroke young
- You are a woman under 60 who has been told her risk is low but wants that checked properly
- Chest pain, pressure or tightness on exertion, which needs assessment now and not a calcium score
- New breathlessness or a sharp fall in exercise tolerance
- LDL cholesterol of 190 mg/dL or above, which needs treatment regardless of any scan result
How Dr. Felix Assesses This
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1
Risk factors first
Blood pressure, lipids including triglycerides and LDL, smoking, diabetes, weight, kidney function, and the risk enhancers that calculators leave out.
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2
A calculated risk
A validated calculator appropriate to you gives a 10 year figure. Under 30 to 59 with a low or borderline result, a 30 year estimate is added, because some young people with low 10 year risk carry a high lifetime risk.
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3
A calcium score where it will change something
Ordered when the decision is genuinely uncertain, mainly at borderline and intermediate risk. Not ordered at low risk, where it rarely changes anything, and not ordered when LDL is already above 190.
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4
A decision, not a number
The score is combined with your risk factors to decide on statin, blood pressure treatment, aspirin and targets. You leave knowing what your LDL target is and why.
Treatment Options
Executive Health Assessment
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Annual Executive Medical Review
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Why Early Treatment Can Matter
What changes when plaque is found early?
The targets change. Moderate calcification puts you above a 7.5 per cent ten year event rate, which is the accepted threshold for starting preventive treatment, whatever the calculator said.
Above 300, risk is comparable to people who already have diagnosed heart disease, and the LDL target drops to under 55 mg/dL.
Does treating it help?
The evidence is observational but consistent. In a cohort of 13,664 people followed for a median of 9.4 years, those with any coronary calcium who took a statin had significantly fewer events, a hazard ratio of 0.76.
Those with no calcium got no benefit from long term statin treatment unless their baseline risk was high for another reason.
What about aspirin?
Aspirin appears to have net benefit under age 70 when the calcium score is 100 or more, regardless of what the calculator said. Below 100, and at zero, it is not used for prevention, because bleeding risk outweighs the gain.
What about repeating the scan?
If your score was zero, a repeat in three to seven years is reasonable, and mainly worth doing if the result would actually change what you do.
If your score was raised, it is not repeated to see whether treatment is working. That question is answered by your LDL, not by another scan.
Why Early Treatment Can Matter
What changes when plaque is found early?
The targets change. Moderate calcification puts you above a 7.5 per cent ten year event rate, which is the accepted threshold for starting preventive treatment, whatever the calculator said.
Above 300, risk is comparable to people who already have diagnosed heart disease, and the LDL target drops to under 55 mg/dL.
Does treating it help?
The evidence is observational but consistent. In a cohort of 13,664 people followed for a median of 9.4 years, those with any coronary calcium who took a statin had significantly fewer events, a hazard ratio of 0.76.
Those with no calcium got no benefit from long term statin treatment unless their baseline risk was high for another reason.
What about aspirin?
Aspirin appears to have net benefit under age 70 when the calcium score is 100 or more, regardless of what the calculator said. Below 100, and at zero, it is not used for prevention, because bleeding risk outweighs the gain.
What about repeating the scan?
If your score was zero, a repeat in three to seven years is reasonable, and mainly worth doing if the result would actually change what you do.
If your score was raised, it is not repeated to see whether treatment is working. That question is answered by your LDL, not by another scan.
A clear number
One scan, no contrast, no fasting, about the radiation of a mammogram, and a result that predicts events better than any blood marker.
What is being prevented
Heart attack, stroke and cardiac death. A score of 300 or more carries risk comparable to people already diagnosed with heart disease.
A decision either way
A score of zero is the strongest de risking result available, and often means no statin. A high score gives you a target rather than an argument.
Cost & Consultation Investment
The consultation, the blood tests and the calcium score are quoted separately, and you are told what each costs before anything is ordered. A calcium score is only recommended where the result would actually change the plan, which is mainly at borderline and intermediate risk. If your calculated risk is low, or your LDL is already above 190, you will be told the scan is not worth doing rather than sold one.
Frequently Asked Questions
No. A stress test looks for narrowing that limits blood flow, usually in people with symptoms. A calcium score measures how much plaque is present in someone without symptoms, and predicts future events.
Under 1 mSv, comparable to a screening mammogram at about 0.8 mSv. Modern scanners can do it below 0.4 mSv.
No. No fasting, no contrast, no beta blockers, no cannula. You need to lie still and hold your breath for three to five seconds.
You are at low risk, and it is the strongest reassuring result available. It is not a guarantee, and it does not apply if you have symptoms, familial hypercholesterolaemia, LDL above 190, diabetes or you smoke.
No. Calcium score measures plaque burden, not blockage. Routine stress testing or CT angiography is not done in people without symptoms, even with a high score.
Male competitive athletes do tend to have higher calcium scores than non athletes. That difference is not seen in female athletes. The result still needs interpreting in context rather than dismissing.
If your calculated risk is low, the scan is unlikely to change anything and is not recommended. The test earns its place when the decision is genuinely uncertain.
Evidence
Where this information comes from
Every figure on this page is taken from the sources below. All of them are free to read, so you can check them yourself.
- Cardiovascular diseases
- Cardiovascular disease: risk assessment and reduction
- Hypertension in adults: diagnosis and management
This page is general medical information and does not replace a personal consultation. Trial results are averages across large groups, not a prediction for any one person.