How the score is measured
The scan takes a few seconds, needs no contrast injection and uses a very low radiation dose. Software adds up every fleck of calcium in the coronary arteries, weighted by its density, to produce an Agatston score. The same number can be read from the first part of a CT coronary angiogram.
Reading the number
- 0: no detectable calcified plaque. The risk of a heart attack over the next five to ten years is low, and for many people this means cholesterol medication can be deferred. It does not rule out soft, non-calcified plaque, which is why a person with symptoms may still need a CT coronary angiogram.
- 1–99: mild plaque. Risk is modestly increased. Lifestyle measures matter, and cholesterol-lowering medication is often recommended depending on age and other risk factors.
- 100–399: moderate plaque. Statin treatment is generally recommended, along with blood pressure control and, in some cases, low-dose aspirin. Further testing is considered if there are symptoms.
- 400 and above: extensive plaque. Risk is high, treatment is intensified, and a test that shows whether any narrowing limits blood flow, such as a stress echocardiogram, is often arranged even without symptoms.
Age and sex matter
The score is also reported as a percentile for your age and sex. A score of 50 in a 45-year-old woman is more concerning than a score of 50 in a 75-year-old man, because it shows plaque building up early. A/Prof Verjans uses both the absolute number and the percentile to decide how aggressively to treat.
What a high score does not mean
A high score does not mean an artery is blocked, and it does not by itself mean you need a stent. Calcium is a marker of the amount of disease, not of how much a particular narrowing limits blood flow. Most people with a high score are treated with medication, and stents are reserved for those with symptoms and a flow-limiting narrowing.
Can the score go down?
Usually not. Statins can actually increase the calcium score slightly as they convert soft plaque into stable, calcified plaque, which is a good thing. For this reason the score is not repeated to track treatment; it is a one-off risk assessment, best done between the ages of about 40 and 75 in people at intermediate risk.
Who should have one
People with no symptoms but a family history of early heart disease, borderline cholesterol, diabetes, or uncertainty about whether to start medication. If you have symptoms such as chest pain or breathlessness on exertion, a CT coronary angiogram is usually the better test, because it shows the artery itself. If your cholesterol is very high or heart disease runs early in your family, ask about familial hypercholesterolaemia; and a bulk-billed echocardiogram is the right test when the question is how well the heart is pumping rather than whether the arteries have plaque.