❤️ Coronary Artery Calcium Score Risk Reclassification Simulator

Pooled Cohort Equations Place the Patient in an Intermediate Zone

Traditional risk factors alone leave many patients in an ambiguous middle category.

• 7.5–20%: PCE risk band (Intermediate 10-yr ASCVD risk)
• Uncertain: Guideline role (Statin decision not clear-cut)
• CAC scan: Next step (Class IIa recommendation)
• ~30%: Population share (Adults fall in this band)

Why intermediate risk needs more data

Risk calculators alone cannot decide statin therapy for everyone.

Non-Contrast Gated CT Captures the Coronary Tree

A quick, low-dose scan images calcium deposits along the arteries.

• ~1 mSv: Radiation dose (Low-dose gated protocol)
• <10 sec: Scan time (Single breath-hold)
• None: Contrast used (Non-contrast acquisition)
• 3 mm: Slice thickness (Standard CAC protocol)

Imaging protocol basics

ECG-gated slices freeze cardiac motion during the sweep.

Density-Weighted Plaque Area Yields the Agatston Score

Each calcified focus is scored by area and peak density.

• Area × density: Formula basis (Weighted factor 1–4)
• ≥130 HU: Threshold (Pixel calcium cutoff)
• 0–1000+: Score range (Agatston units)
• ~5 min: Reader time (Semi-automated software)

Scoring calcified lesions

Software sums weighted area across all detected plaques.

Zero Calcium Supports Stepping the Risk Category Down

A CAC of zero often means statins can be safely deferred.

• ~50%: CAC=0 prevalence (Of intermediate-risk adults)
• ~5 years: Warranty period (Low event rate window)
• Reasonable: Statin deferral (Per guideline consensus)
• High: NPV (Very low near-term events)

The power of a negative scan

Absence of calcium reclassifies many patients to low risk.

High CAC Reclassifies the Patient Upward to High Risk

A high score triggers earlier, more intensive statin therapy.

• ≥300: High CAC cutoff (Agatston units)
• ≥75th: Percentile flag (Age/sex adjusted)
• High: Statin intensity (Guideline-directed escalation)
• ↑ 2–3×: Event risk (Vs. baseline PCE estimate)

Acting on a high score

High CAC prompts high-intensity statins and closer follow-up.

CAC scoring reclassifies roughly one in three intermediate-risk patients.