Coronary Calcium Score: Who Should Get One

A coronary calcium score comes from a quick CT scan of the heart with no dye and no needle. It takes a few minutes, the radiation dose is about the same as a mammogram, and the cash price in most markets is roughly $100 to $200. What it gives back is a single number that a cholesterol panel cannot: whether plaque has already formed in the arteries that feed the heart.

What the scan measures

Plaque starts as a soft deposit of cholesterol inside the artery wall. Over years the body walls some of it off with calcium. The scan sees that calcium and adds it up. Zero means none was found. A score of 1 to 99 is mild, 100 to 399 is moderate, and 400 or above is extensive. In large groups of people the risk of a heart attack rises with the number.

The catch is that the scan only sees calcified plaque. Soft plaque, the kind that has not had years to calcify, is invisible to it. It is also the plaque a younger person is most likely to have.

Who it helps

The test earns its keep in the middle. The person it helps is the 45 to 70 year old with a mixed picture: a borderline LDL or ApoB, a parent who had a heart attack in their 50s, a sedentary decade. In that group the question is usually whether to start medication, and the score often settles it. A high score makes the case for treatment plain. A zero in someone over about 55 who does not smoke, does not have diabetes and has no early heart disease in the family means no calcified plaque has formed, and cohort studies show a low event rate in that group for years, so a statin can often wait.

Family history is the other strong reason. Risk calculators lean on age and cholesterol and give little weight to inheritance. A scan does not care what the calculator predicted. It shows what is there.

Why zero is not a free pass under 50

Calcium takes years to lay down. A 42 year old with a high ApoB and a zero score may have real soft plaque that has not hardened yet. In that person a zero should not cancel a decision to lower particle count. If we need to see soft plaque, a CT angiogram with dye is the test that shows it.

Two other rules. A score does not fall with treatment, and statins can raise it slightly by hardening soft plaque into the stable kind, so we do not rescan to judge whether a medication is working. A zero in a lower risk person usually holds for about five years.

We look at ApoB, Lp(a) and family history first, then decide whether the scan adds something. If nobody has walked through that with you, it's worth a conversation.

This article is educational and is not medical advice.

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