Purpose of the Atherosclerotic Cardiovascular Disease (ASCVD) Score
The primary purpose of the ASCVD score is to assess an individual's 10-year risk of developing atherosclerotic cardiovascular disease events (such as myocardial infarction or stroke) to guide appropriate preventive interventions, particularly decisions regarding statin therapy initiation.
What is the ASCVD Score?
The ASCVD score is calculated using the Pooled Cohort Equations (PCE) developed by the American College of Cardiology (ACC) and American Heart Association (AHA). It provides a percentage risk estimate of experiencing a first cardiovascular event within the next 10 years.
Key components of the ASCVD risk calculator:
- Age
- Sex
- Race (Black vs. non-Black)
- Total cholesterol
- HDL cholesterol
- Systolic blood pressure
- Treatment for hypertension
- Diabetes status
- Smoking status
Clinical Applications of the ASCVD Score
Risk Stratification Categories
The ASCVD risk score categorizes patients into risk groups 1:
- Low risk: <5% 10-year risk
- Borderline risk: 5% to <7.5% 10-year risk
- Intermediate risk: 7.5% to <20% 10-year risk
- High risk: ≥20% 10-year risk
Treatment Decision-Making
The ASCVD score serves as the foundation for:
Statin therapy decisions:
- Guides whether to initiate statin therapy based on risk thresholds
- Helps determine appropriate statin intensity (low, moderate, or high)
Risk-enhancing factor assessment:
- For patients with borderline (5% to <7.5%) or intermediate risk (7.5% to <20%), additional risk-enhancing factors can guide preventive interventions 1
Coronary artery calcium (CAC) scoring decisions:
- In intermediate-risk patients or selected borderline-risk patients, CAC scoring can further refine risk assessment when treatment decisions remain uncertain 1
Limitations and Refinements
Potential Miscalibration
The ASCVD score may overestimate or underestimate risk in certain subgroups 1. This has led to recommendations for additional risk assessment tools to refine predictions.
Role of Coronary Artery Calcium (CAC) Scoring
CAC scoring provides direct visualization of atherosclerosis and can significantly improve risk prediction:
- For patients with ASCVD risk <5%, CAC can confirm low-risk status or reclassify to higher risk 1
- For patients with ASCVD risk 5-20%, CAC can reclassify risk up or down 1
- For patients with ASCVD risk >20%, CAC is generally not recommended except in special circumstances 1
CAC scoring is particularly valuable in intermediate-risk patients where approximately half may be reclassified into a very low-risk category 2, potentially avoiding unnecessary statin therapy.
Clinical Implementation
Recommended Assessment Schedule
- Adults 40-75 years: Routine assessment of traditional cardiovascular risk factors and calculation of 10-year ASCVD risk using the PCE 1
- Adults 20-39 years: Assessment of traditional ASCVD risk factors at least every 4-6 years 1
- For younger adults with low short-term risk, lifetime or 30-year ASCVD risk estimation may be considered 1
Risk Discussion Process
The ASCVD score should initiate a clinician-patient discussion about risk-reducing strategies rather than serve as the sole decision factor for pharmacotherapy 1. This discussion should include:
- Review of calculated 10-year risk
- Consideration of risk-enhancing factors
- Discussion of CAC scoring when risk-based decisions remain uncertain
- Shared decision-making about preventive interventions
Common Pitfalls to Avoid
Treating the score in isolation: The ASCVD score should be the start of a risk discussion, not the sole determinant of treatment 1
Overlooking risk-enhancing factors: Additional factors beyond the calculator can significantly modify risk assessment 1
Ignoring age-specific considerations: For adults >75 years, discussions should consider benefits of preventive therapies in the context of comorbidities and life expectancy 1
Failing to recognize limitations in certain populations: The calculator may perform differently in various ethnic groups and special populations 1, 3
Missing opportunities for CAC scoring: In intermediate-risk patients, CAC scoring can significantly reclassify risk and alter treatment decisions 1, 2
The ASCVD risk calculator remains a cornerstone of cardiovascular risk assessment, but should be used as part of a comprehensive approach that includes consideration of additional risk factors, potential use of CAC scoring, and shared decision-making with patients.