Evaluation

Coronary Calcium Score

Your calcium score is more than a test

The coronary artery calcium score is a low-dose, non-contrast CT scan that detects and quantifies calcified atherosclerotic plaque within the coronary arteries. Calcium deposition is a reliable marker of overall coronary plaque burden — including both calcified and non-calcified components — and provides prognostic information that is independent of and incremental to traditional cardiovascular risk factors. The CAC score is the single strongest non-invasive predictor of future cardiac events in asymptomatic individuals and is increasingly used to guide statin initiation, intensity of preventive therapy, and the decision to proceed to CT coronary angiography.

Interpreting Your CAC Score

Results are reported as an Agatston score — a standardised measure of calcified plaque area and density across all four coronary arteries.

Agatston Score

Interpretation : Clinical Implication

0 : No calcified plaque detected

Very low near-term cardiac event risk; statin initiation may be deferred in intermediate-risk patients

1–99 : Mild calcification

Mild atherosclerosis; risk factor optimisation and consideration of statin therapy

100–399 : Moderate calcification

Moderate-to-high atherosclerotic burden; statin therapy indicated; further evaluation may be warranted

400 and above : Severe calcification

High coronary plaque burden; high cardiovascular event risk; aggressive medical therapy and specialist review

Score results are also reported as an age-, sex-, and ethnicity-adjusted percentile — contextualising the individual score against peers of the same demographic. A score in the 75th percentile or above indicates disproportionate plaque burden for age and triggers more intensive preventive intervention regardless of absolute score.

Clinical Value of a Zero Score

A CAC score of zero is one of the most powerful negative predictive findings in cardiovascular medicine. It indicates absence of detectable calcified plaque and is associated with an annual cardiac event rate below 1% over the subsequent 5–10 years in intermediate-risk individuals. In patients with borderline cardiovascular risk where statin initiation is uncertain, a zero score supports deferring pharmacotherapy with close clinical monitoring. However, a zero score does not exclude non-calcified (soft) plaque — CT coronary angiography is required if symptomatic ischaemia is suspected despite a zero CAC.

Who Should Have a CAC Score

CAC scoring is most beneficial in intermediate-risk asymptomatic individuals — those where traditional risk factor assessment leaves the decision to treat uncertain. It is particularly valuable in patients aged 40–75 with one or more cardiovascular risk factors (hypertension, hyperlipidaemia, diabetes, smoking, family history of premature CAD) where the clinical benefit of statin therapy is unclear. Patients with familial hypercholesterolaemia benefit from early CAC assessment to guide treatment intensity given their high lifetime exposure to elevated LDL. CAC scoring is not recommended in patients with established cardiovascular disease — where statin therapy and secondary prevention are already indicated — or in patients with acute cardiac symptoms, where CT coronary angiography or stress testing is more appropriate.

How the Scan Is Performed

The CAC scan requires no preparation, no fasting, no contrast injection, and no medication adjustment. The patient lies in a CT scanner for approximately five minutes while a series of ECG-gated images are acquired during a brief breath-hold. Radiation exposure is low — approximately 1–2 mSv, comparable to a transatlantic flight. Results are available within 24–48 hours and reviewed by Dr. Peter Chang in the context of the full cardiovascular risk profile.

CAC Score vs. CT Coronary Angiography

The CAC score quantifies calcified plaque burden but does not assess non-calcified plaque, stenosis severity, or coronary anatomy. CT coronary angiography (CTCA) provides anatomical detail of all plaque types and identifies flow-limiting stenoses. In asymptomatic patients, a high CAC score (400+) or a very high age-adjusted percentile may prompt CTCA to assess whether significant stenosis is present and whether revascularisation evaluation is needed. In symptomatic patients — those with chest pain, breathlessness, or abnormal stress testing — CTCA is the preferred primary investigation rather than CAC scoring alone.

Concerned about hidden cardiovascular risk or unsure whether you need statin therapy? Dr. Peter Chang offers CAC score scanning with expert interpretation at Paragon Medical Centre, Orchard Road. Book a cardiovascular risk assessment today.