Coronary artery calcium screening

CAC scan is a non‑contrast CT that quantifies coronary artery calcium. It is primarily used to refine cardiovascular risk when the decision to start or intensify preventive therapy is uncertain. A CAC score of 0 indicates very low short‑term risk; statin therapy can often be deferred unless the patient has diabetes, smokes, has a strong family history of premature CAD, or markedly elevated Lp(a). A score >0 signals increasing risk: scores 1–99 suggest considering statins in individuals older than 40; scores ≥100 (or ≥75th percentile for age/sex) strongly support statin use and tighter LDL/ApoB targets; very high scores (≥300–400) indicate substantial plaque burden and warrant aggressive risk‑factor control, including lifestyle modification and LDL lowering. In Indian populations, a baseline CAC scan is recommended after age 30–35 for those not already on preventive statins, using Indian age‑specific reference values; a high score for age prompts aggressive LDL lowering and lifestyle measures. The test delivers low radiation (~1 mSv), is not indicated for patients with known CAD or during unstable symptoms, and does not replace clinical evaluation.