Recommended ASCVD Score for Cardiovascular Risk Assessment
The recommended ASCVD score threshold for guiding preventive interventions is 7.5% for 10-year risk, with borderline risk defined as 5% to <7.5%, and consideration of coronary artery calcium (CAC) scoring for risk refinement in these categories. 1
ASCVD Risk Categories and Thresholds
The American College of Cardiology/American Heart Association (ACC/AHA) guidelines define ASCVD risk categories as follows:
- Low risk: <5% 10-year ASCVD risk
- Borderline risk: 5% to <7.5% 10-year ASCVD risk
- Intermediate risk: 7.5% to <20% 10-year ASCVD risk
- High risk: ≥20% 10-year ASCVD risk
These risk categories are calculated using the Pooled Cohort Equations, which incorporate age, sex, race, total cholesterol, HDL cholesterol, systolic blood pressure, treatment for hypertension, diabetes, and current smoking status 1, 2.
Risk-Based Treatment Algorithm
For patients with 10-year ASCVD risk ≥7.5% (Intermediate to High Risk):
- Generally recommended for statin therapy
- High-intensity statin to reduce LDL-C by ≥50% for high-risk patients
- Moderate-intensity statin for intermediate-risk patients 1
For patients with 10-year ASCVD risk 5% to <7.5% (Borderline Risk):
- Consider risk-enhancing factors and shared decision-making
- CAC scoring can guide statin decisions 1
For patients with 10-year ASCVD risk <5% (Low Risk):
- Generally not recommended for statin therapy unless risk-enhancing factors present
- Selected patients with family history of premature ASCVD may benefit from CAC scoring 1
Role of Coronary Artery Calcium (CAC) Scoring in Risk Refinement
CAC scoring provides significant value in refining ASCVD risk assessment, particularly for borderline and intermediate-risk patients:
- CAC = 0: Consider withholding statin therapy in patients without diabetes, active smoking, or family history of premature ASCVD 1
- CAC = 1-99: Consider moderate-intensity statin therapy 1
- CAC ≥100 or ≥75th percentile for age/sex/race: Recommend moderate to high-intensity statin therapy 1
CAC scoring has demonstrated superior discrimination compared to risk calculators alone in identifying patients with high atherosclerotic burden 3. Studies show that CAC = 0 identifies a large group of patients at very low risk despite being statin-eligible by the Pooled Cohort Equations 1.
Impact on Treatment Decisions
Incorporating CAC scoring into risk assessment can significantly impact treatment decisions:
- Approximately 57% of borderline-risk patients have CAC = 0 with an ASCVD event rate of only 1.5% (statins not recommended) 1
- In contrast, borderline-risk patients with CAC > 0 have a 7.4% event rate (statins recommended) 1
- Similarly, in intermediate-risk patients, those with CAC = 0 have a 4.6% event rate versus 10.4% in those with CAC > 0 1
This approach can reclassify statin eligibility in approximately 14% of patients, preventing unnecessary statin therapy in some while identifying others who would benefit despite lower calculated risk 1.
Important Caveats and Considerations
- Age is the strongest contributor to 10-year predicted ASCVD risk. Even older adults without traditional risk factors may have elevated ASCVD risk and experience events 4
- CAC scoring is not recommended for patients with established ASCVD, as they already qualify for intensive preventive therapy 1
- CAC = 0 does not exclude obstructive coronary artery disease in symptomatic patients 1
- Risk-enhancing factors (family history of premature ASCVD, elevated inflammatory markers, etc.) should be considered when ASCVD risk calculation falls in borderline zones 1, 2
By using the recommended ASCVD risk thresholds and incorporating CAC scoring when appropriate, clinicians can more accurately identify patients who will benefit most from preventive interventions while avoiding unnecessary treatment in others.