How should Atherosclerotic Cardiovascular Disease (ASCVD) risk be estimated and managed in patients at risk?

ASCVD Risk Assessment and Management

Primary Risk Assessment Tool

For adults aged 40-79 years, use the Pooled Cohort Equations (PCE) as your initial risk assessment tool to calculate 10-year ASCVD risk, which includes myocardial infarction, stroke, and cardiovascular death. 1

The PCE incorporates age, sex, race (Black vs. White), total cholesterol, HDL cholesterol, systolic blood pressure, antihypertensive treatment status, diabetes, and smoking status. 1, 2

Risk Categories and Treatment Thresholds

The 10-year ASCVD risk stratifies patients into four actionable categories 2, 3:

• Low risk (<5%): Lifestyle modifications only 2
• Borderline risk (5% to <7.5%): Consider statin therapy only if risk-enhancing factors are present 1, 2
• Intermediate risk (7.5% to <20%): Statin therapy should be initiated after clinician-patient discussion 1, 2
• High risk (≥20%): Statin therapy is mandatory 2

Risk Refinement Strategies

When to Use Risk-Enhancing Factors

For borderline and intermediate-risk patients where treatment decisions remain uncertain, incorporate these risk-enhancing factors 1, 2:

• Family history of premature ASCVD (men <55 years, women <65 years)
• Persistently elevated LDL-C ≥160 mg/dL
• Chronic kidney disease (eGFR 15-59 mL/min/1.73m²)
• Chronic inflammatory conditions (rheumatoid arthritis, psoriasis, HIV, inflammatory bowel disease)
• Metabolic syndrome
• South Asian ancestry
• Elevated high-sensitivity CRP (≥2.0 mg/L)
• Elevated lipoprotein(a) (≥50 mg/dL or ≥125 nmol/L)
• Elevated apolipoprotein B (≥130 mg/dL)

Coronary Artery Calcium (CAC) Scoring

Use CAC scoring when statin therapy decisions remain uncertain after calculating PCE risk and considering risk-enhancing factors, particularly in intermediate-risk patients. 1, 2

CAC score interpretation for treatment decisions 1:

• CAC = 0: Withhold statin therapy; reassure patient and focus on lifestyle modifications 1
• CAC 1-99: Favor lifestyle improvements; consider statin if >75th percentile for age/sex 1
• CAC 100-400: Strongly favor statin therapy 1
• CAC >400: Initiate high-intensity statin therapy plus aspirin 81 mg daily (if not high bleeding risk) 1

Special Population Considerations

Younger Adults (20-39 Years)

Assess traditional ASCVD risk factors every 4-6 years. 1 For adults 20-59 years, consider calculating lifetime or 30-year ASCVD risk rather than 10-year risk to capture long-term implications of risk factor burden. 1, 3

Patients with Diabetes

The PCE includes diabetes as a risk factor, though it does not account for diabetes duration or complications like albuminuria. 1 The calculator remains valid for patients with diabetes. 1

For diabetic patients with hypertension 1:

• Higher cardiovascular risk (existing ASCVD or ≥15% 10-year risk): Target BP <130/80 mmHg
• Lower cardiovascular risk (<15% 10-year risk): Target BP <140/90 mmHg

Populations Where PCE May Underestimate Risk

The PCE systematically underestimates risk in 1, 2:

• Chronic inflammatory conditions (ulcerative colitis, rheumatoid arthritis, HIV, psoriasis)
• Patients with socioeconomic disadvantage
• Chronic kidney disease with reduced eGFR

Populations Where PCE May Overestimate Risk

The PCE may overestimate risk in patients with excellent access to care and strong adherence to lifestyle modifications. 1 Recent data shows the PCE overestimates risk compared to contemporary cohorts, particularly in Black adults and those aged 70-75 years. 4, 5

Alternative Risk Calculators

PREVENT Equations (2023)

The newer PREVENT equations estimate 10-year and 30-year risk of ASCVD, CVD, and heart failure for adults aged 30-79 years. 4, 5 Key differences from PCE:

• Removes race as a variable
• Adds kidney function (eGFR and urine albumin-creatinine ratio)
• Includes current statin use
• Derived from more contemporary cohorts

PREVENT equations predict lower ASCVD risk than PCE across all demographic groups, with the largest differences in Black adults (10.9% vs 5.1%) and adults aged 70-75 years (22.8% vs 10.2%). 4 In the MESA cohort, PREVENT demonstrated better calibration than PCE, particularly in women, nonsmokers, patients with chronic kidney disease, and those with social deprivation. 5

Other Calculators for Specific Populations

Consider these alternatives when appropriate 2:

• MESA CAC calculator: Incorporates CAC score for 10-year CHD risk
• Reynolds Risk Score: Incorporates high-sensitivity CRP
• Framingham Risk Score: Historically used but now superseded by PCE

Critical Limitations and Pitfalls

Do Not Use Risk Calculators In:

• Patients with established ASCVD (prior MI, stroke, revascularization, peripheral arterial disease) 2
• Symptomatic patients requiring diagnostic evaluation 2

Common Errors to Avoid:

• Never rely solely on the calculated risk number without considering clinical context, risk-enhancing factors, and patient preferences 1, 2
• Do not use CAC scoring in symptomatic patients or those with established ASCVD 2
• Do not neglect lifestyle modifications regardless of whether pharmacotherapy is initiated 2
• Do not forget to reassess risk periodically, as risk factors change over time 2
• Do not make unilateral decisions without engaging patients in shared decision-making about preventive strategies 1, 2

Ethnic Group Limitations:

For Hispanic, Asian-American, and American Indian populations, use the sex-specific PCE for non-Hispanic Whites, recognizing this is an imperfect approximation. 1 ASCVD risk is generally lower in Hispanic and Asian-American populations and higher in American Indian populations compared to non-Hispanic Whites. 1

Practical Clinical Algorithm

1. Calculate baseline 10-year ASCVD risk using PCE (or PREVENT if available) for adults 40-79 years 1, 2

2. Categorize risk level (<5%, 5-7.5%, 7.5-20%, ≥20%) 2

3. For high-risk patients (≥20%): Initiate high-intensity statin therapy immediately 2

4. For intermediate-risk patients (7.5-20%): Recommend statin therapy after shared decision-making discussion 1, 2

5. For borderline-risk patients (5-7.5%): Assess risk-enhancing factors; if present, consider statin therapy 1, 2

6. If uncertainty persists in borderline or intermediate-risk patients: Order CAC scoring to reclassify risk upward or downward 1

7. Implement appropriate therapy based on final risk stratification, including lifestyle modifications, statin therapy, blood pressure management, and aspirin (if CAC >400 and not high bleeding risk) 1, 2

8. Reassess risk annually by evaluating traditional cardiovascular risk factors 1

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