What are the statin (HMG-CoA reductase inhibitor) indications for someone with known Coronary Artery Disease (CAD) but no history of Myocardial Infarction (MI)?

Statin Therapy for Known CAD Without Prior MI

For patients with known coronary artery disease (CAD) but no history of myocardial infarction, high-intensity statin therapy is indicated for all patients ≤75 years of age, and moderate-to-high-intensity statin therapy is reasonable for those >75 years. 1

Primary Recommendation by Age

Patients ≤75 Years Old

• High-intensity statin therapy should be initiated or continued as first-line therapy (Class I recommendation) 1
• High-intensity statins include: 1
  • Atorvastatin 40-80 mg daily
  • Rosuvastatin 20-40 mg daily
• If high-intensity statin is contraindicated or not tolerated, use moderate-intensity statin therapy (Class I recommendation) 1
• Moderate-intensity options include: 1
  • Atorvastatin 10-20 mg daily
  • Rosuvastatin 5-10 mg daily
  • Simvastatin 20-40 mg daily
  • Pravastatin 40-80 mg daily

Patients >75 Years Old

• It is reasonable to initiate moderate- or high-intensity statin therapy after evaluating potential benefits, adverse effects, drug-drug interactions, frailty, and patient preferences (Class IIa recommendation) 1
• If already tolerating high-intensity statin therapy, it is reasonable to continue (Class IIa recommendation) 1
• Recent evidence in older CAD patients (≥65 years) showed that moderate-intensity statins provided similar outcomes to high-intensity statins, supporting the guideline's more conservative approach in this age group 2

FDA-Approved Indications

The FDA labels explicitly support statin use for patients with clinically evident CAD: 3, 4

• Pravastatin is indicated "to reduce the risk of coronary death, myocardial infarction, myocardial revascularization procedures, stroke or transient ischemic attack, and slow the progression of coronary atherosclerosis in adults with clinically evident CHD" 3
• Atorvastatin is indicated "to reduce non-fatal MI, fatal and non-fatal stroke, revascularization procedures, hospitalization for congestive heart failure, and angina in adults with clinically evident CHD" 4

Intensification Strategy for Very High-Risk Patients

If the patient meets "very high-risk" criteria (multiple major ASCVD events OR one major ASCVD event plus multiple high-risk conditions), consider additional therapy: 1

Very high-risk is defined as: 1

• History of multiple major ASCVD events (recent ACS within 12 months, history of MI, ischemic stroke, symptomatic PAD), OR
• One major ASCVD event PLUS multiple high-risk conditions (diabetes, hypertension, CKD with eGFR 15-59, current smoking, persistently elevated LDL-C ≥100 mg/dL on maximally tolerated statin, history of heart failure)

For very high-risk patients on maximally tolerated statin with LDL-C ≥70 mg/dL: 1

• Adding ezetimibe is reasonable (Class IIa recommendation) 1
• If LDL-C remains ≥70 mg/dL or non-HDL-C ≥100 mg/dL on maximal statin plus ezetimibe, adding a PCSK9 inhibitor is reasonable (Class IIa recommendation), though cost-effectiveness is limited at current pricing 1

Important Clinical Considerations

Drug Interactions and Monitoring

• Evaluate for potential drug-drug interactions, particularly in older patients on multiple medications 1
• Monitor for statin-associated muscle symptoms (SAMS), especially with higher doses 1, 4
• Consider baseline and follow-up liver enzyme testing as clinically indicated 4

Special Populations

• Patients with heart failure with reduced ejection fraction due to ischemic heart disease: Consider moderate-intensity statin if reasonable life expectancy (3-5 years) and not already on statin for ASCVD (Class IIb recommendation) 1
• Patients with chronic kidney disease: Use moderate-intensity statins rather than high-intensity in those with eGFR <60 mL/min/1.73 m² 1

Common Pitfalls to Avoid

• Do not withhold statins based solely on LDL-C levels - the benefit in established CAD is independent of baseline LDL-C 1, 5
• Do not delay initiation - statins should be started before hospital discharge in acute settings to improve adherence 1
• Do not undertitrate in younger patients - high-intensity therapy provides incremental benefit in those ≤75 years 1, 6
• Do not automatically use high-intensity statins in patients >75 years - moderate-intensity may be equally effective with better tolerability 7, 2

Evidence Quality

The recommendations are based on multiple large randomized controlled trials demonstrating that statins reduce cardiovascular events, coronary revascularization, and all-cause mortality in patients with established CAD 1, 8, 9. The Cholesterol Treatment Trialists meta-analysis showed a 15% additional reduction in major vascular events with more intensive versus less intensive statin regimens 1. Recent real-world evidence confirms these benefits extend across the spectrum of CAD severity, even in patients without obstructive disease 9.