What does the Agatston score indicate about coronary artery calcium and cardiovascular risk?

What the Agatston Score Means

The Agatston score is a quantitative measure of coronary artery calcification that reflects your total atherosclerotic plaque burden and predicts future cardiovascular risk—higher scores indicate more extensive coronary atherosclerosis and progressively greater risk of heart attack and cardiac death. 1

How the Score is Calculated

• The Agatston algorithm identifies calcified lesions as areas with CT density >130 Hounsfield units and size >1 mm², then assigns a weighting factor of 1-4 based on density 1
• Your total score is calculated by multiplying each lesion's area by its weighting factor, then summing all calcified lesions across all coronary arteries 1
• The score can be expressed as a raw number or as a percentile adjusted for your age, sex, and race 1

What Different Score Ranges Mean for Your Risk

Score = 0 ("The Power of Zero")

• Indicates excellent prognosis with <1% annual risk of cardiac death or heart attack—this is considered very low risk 1
• In a systematic review of 71,595 asymptomatic patients, only 0.47% with zero calcium had cardiovascular events over 50 months of follow-up 1
• Even symptomatic patients with zero calcium have annual mortality <0.5% 1
• Important caveat: Zero calcium does NOT exclude non-calcified plaque, which can still be present in early atherosclerosis 2, 3

Score = 1-99 (Mild Calcification)

• Confirms presence of atherosclerosis with incrementally increased risk above zero 1
• Places you at approximately 7.4% 10-year cardiovascular risk in intermediate-risk populations 3
• Warrants lifestyle modifications and consideration of statin therapy, especially if your score is ≥75th percentile for your age/sex/race 3

Score = 100-399 (Moderate Calcification)

• Indicates ≥7.5% 10-year cardiovascular disease risk regardless of your demographic characteristics 3
• Statin therapy benefits clearly exceed potential harm at this level 3
• Requires moderate-to-high intensity statin targeting ≥30-50% LDL-C reduction 3
• Associated with 10-20% 10-year cardiovascular event rate 3

Score = 400-999 (Severe Calcification)

• Denotes high risk with >20% 10-year event rate 3, 4
• The 2010 ACC/AHA guidelines recommend screening for clinically silent ischemia when scores exceed 400 1
• Requires aggressive preventive therapy including high-intensity statins, blood pressure control <130/80 mmHg, and comprehensive lifestyle modification 3, 4
• Associated with 7.2- to 10.8-fold increased risk of coronary death or heart attack compared to zero calcium 3

Score ≥1000 (Extensive Calcification)

• Indicates extremely elevated risk with continuous graded decrease in survival as scores increase beyond 1000 5
• Scores >2000 carry 13.26-fold greater mortality risk compared to zero calcium 5
• Requires maximal intensity risk-factor modification and close clinical follow-up every 3-6 months 4

Critical Limitations You Must Understand

• Calcium score reflects atherosclerotic burden, NOT degree of arterial narrowing—only 20% of total atherosclerosis contains calcium, and arterial remodeling often preserves lumen patency despite extensive plaque 3, 4
• The score has only 50% specificity for detecting ≥50% stenosis, meaning high calcium does NOT necessarily indicate blockages requiring stents or bypass 1, 4
• Calcium scoring cannot detect non-calcified "soft" plaques, which may represent more vulnerable, rupture-prone lesions 2, 3
• The European Society of Cardiology emphasizes that coronary calcification is neither a marker of plaque stability nor instability—it simply indicates total disease burden 1, 4

When Calcium Scoring is Most Useful

• Primary indication: Asymptomatic adults aged 40-75 with intermediate (7.5-20%) or borderline (5-7.5%) 10-year cardiovascular risk when statin decisions are uncertain 1, 3
• Helps reclassify risk in patients with risk-enhancing factors: family history of premature coronary disease, elevated lipoprotein(a) >50 mg/dL, metabolic syndrome, chronic inflammatory conditions 3
• NOT appropriate for symptomatic patients with chest pain—in the CONFIRM registry, 3.5% of symptomatic patients with zero calcium still had ≥50% stenosis 3

Common Pitfalls to Avoid

• Do not use calcium scoring to determine need for revascularization or replace functional testing when assessing for blockages 3
• Do not assume zero calcium excludes coronary disease in symptomatic patients—7-38% of symptomatic patients with zero calcium have obstructive disease 3
• Do not order calcium scoring in truly low-risk patients (<5% 10-year risk) as it rarely changes management 3
• Remember that statin therapy may paradoxically increase calcification over time, which does not indicate worsening prognosis 3