What is the initial treatment for Coronary Artery Disease (CAD)?

Initial Treatment for Coronary Artery Disease

For patients with established chronic coronary artery disease, initiate low-dose aspirin (75-100 mg daily) as the cornerstone of antiplatelet therapy, combined with a beta-blocker for symptom control, and high-intensity statin therapy regardless of baseline LDL cholesterol. 1

Antiplatelet Therapy for Event Prevention

Single antiplatelet therapy is the standard for stable CAD:

• Aspirin 75-100 mg once daily is the first-line antiplatelet agent, reducing the combined risk of non-fatal MI, non-fatal stroke, or vascular death from 8.2% to 6.7% per year, translating to 15 fewer serious vascular events per 1000 patients treated annually. 1

• Clopidogrel 75 mg daily is the alternative if aspirin is absolutely contraindicated or not tolerated. 1

• Dual antiplatelet therapy (aspirin plus clopidogrel) is NOT recommended for stable CAD beyond 12 months post-acute coronary syndrome or post-PCI, as single antiplatelet therapy is preferred to reduce bleeding risk. 1

Important caveat: While aspirin increases major GI and extracranial bleeding from 0.07% to 0.10% per year, the reduction in ischemic events substantially outweighs bleeding risks in secondary prevention. 1

Antianginal Therapy for Symptom Control

Beta-blockers are the initial antianginal medication for most patients:

• Start with a beta-blocker (e.g., metoprolol) targeting a heart rate of 50-60 beats per minute unless contraindications exist (sick sinus syndrome, atrioventricular conduction disorders, severe PAD, or severe COPD). 1

• Short-acting nitrates (sublingual nitroglycerin 0.4 mg) should be prescribed for immediate relief of breakthrough angina symptoms. 1, 2

If beta-blocker monotherapy fails to control symptoms:

• Add a dihydropyridine calcium channel blocker (CCB) as the preferred combination for most patients. 1

• Avoid combining beta-blockers with non-dihydropyridine CCBs (verapamil or diltiazem) due to excessive bradycardia risk. 1

If beta-blockers are contraindicated or not tolerated:

• Use long-acting nitrates, ranolazine, nicorandil, or trimetazidine as alternative first-line agents, particularly in patients with low heart rate or blood pressure. 1

Lipid-Lowering Therapy

High-intensity statin therapy is mandatory:

• Initiate high-intensity statin therapy immediately (e.g., atorvastatin 40-80 mg or rosuvastatin 20-40 mg) regardless of baseline LDL cholesterol level, with a target LDL <100 mg/dL (ideally <70 mg/dL). 1, 2, 3

• No evidence supports routine use of nonstatin monotherapy (bile acid sequestrants, niacin, ezetimibe, or fibrates) as alternatives. 4

ACE Inhibitor Therapy

ACE inhibitors provide mortality benefit beyond blood pressure control:

• Start an ACE inhibitor (e.g., enalapril, ramipril, or perindopril) in all CAD patients, particularly those with diabetes, left ventricular dysfunction (LVEF ≤40%), hypertension, or heart failure. 1, 3, 5

• ACE inhibitors reduce cardiovascular death, MI, and stroke through mechanisms independent of blood pressure lowering. 5

• Angiotensin receptor blockers (ARBs) are acceptable alternatives if ACE inhibitors are not tolerated. 3

Risk Factor Modification

Lifestyle interventions are non-negotiable:

• Tobacco cessation is the single most important modifiable risk factor and must be addressed at every visit. 4

• Prescribe structured exercise programs (cardiac rehabilitation when available) and weight loss for overweight patients. 3, 4

• Optimize management of diabetes mellitus and hypertension to target goals (HbA1c <7%, BP <130/80 mmHg in most patients). 1, 4

Special Considerations for Acute Presentations

If the patient presents with unstable angina or acute coronary syndrome:

• Immediate hospitalization with continuous ECG monitoring is required, along with aspirin 150-325 mg loading dose, clopidogrel 300-600 mg loading dose, parenteral anticoagulation (enoxaparin, fondaparinux, or unfractionated heparin), and risk stratification for early invasive strategy. 2, 3

• Dual antiplatelet therapy (aspirin plus ticagrelor 90 mg twice daily or clopidogrel 75 mg daily) should continue for 12 months after ACS, then transition to single antiplatelet therapy. 1, 3

Common Pitfalls to Avoid

Do not use aspirin doses >100 mg daily for chronic stable CAD, as higher doses increase bleeding risk without additional efficacy for long-term secondary prevention. 1, 6

Do not continue dual antiplatelet therapy beyond indicated durations (12 months post-ACS or 6 months post-elective PCI) unless the patient has persistently high ischemic risk and low bleeding risk. 1

Do not prescribe short-acting dihydropyridine CCBs (e.g., immediate-release nifedipine) as they may increase adverse cardiovascular events. 1

Do not withhold beta-blockers in patients with prior MI, as they have proven mortality benefit in this population. 1, 7