What is coronary artery disease (CAD) and how is it treated?

Coronary Artery Disease (CAD): Definition and Treatment

Coronary artery disease is atherosclerotic narrowing of the coronary arteries that can present as stable angina, acute coronary syndromes, or asymptomatic ischemia, and is treated with guideline-directed medical therapy (GDMT) as the foundation for all patients, with revascularization reserved for specific high-risk anatomic patterns or refractory symptoms. 1, 2, 3

What is CAD?

CAD results from obstructive atherosclerotic plaque buildup in the coronary arteries that supplies blood to the heart muscle. Patients may be completely asymptomatic, experience stable angina (predictable chest discomfort with exertion), present with acute coronary syndromes (unstable angina or myocardial infarction), or suffer sudden cardiac death 4. The disease exists on a spectrum from mild non-obstructive disease to severe multi-vessel involvement.

The clinical presentation varies significantly:

• Typical angina: Substernal chest pressure/discomfort triggered by exertion or emotional stress, relieved by rest or nitroglycerin within minutes
• Angina equivalents: Dyspnea on exertion, arm/jaw/neck pain, or fatigue (particularly common in women and elderly patients) 3
• Asymptomatic: Many patients have significant disease without symptoms

Treatment Approach: A Hierarchical Strategy

Foundation: Guideline-Directed Medical Therapy (GDMT) for ALL Patients

Every patient with CAD—regardless of symptoms or revascularization plans—must receive comprehensive medical therapy. This is non-negotiable and forms the cornerstone of treatment 4, 1, 2.

1. Antiplatelet Therapy

• Aspirin 81 mg daily indefinitely for all patients 5, 2
• Dual antiplatelet therapy (aspirin + P2Y12 inhibitor) for 12 months after acute coronary syndrome or stent placement:
  • Clopidogrel 75 mg daily, OR
  • Ticagrelor 90 mg twice daily, OR
  • Prasugrel 10 mg daily (post-ACS only) 5

2. Lipid-Lowering Therapy

• High-intensity statin for all patients unless contraindicated 2, 6
• Add ezetimibe if LDL remains elevated on maximum tolerated statin
• Consider PCSK9 inhibitors or inclisiran for very high-risk patients or those with inadequate LDL reduction 6
• Target: LDL-C reduction of ≥50% from baseline

3. Blood Pressure Control

• Target systolic BP 120-130 mmHg (general population) or 130-140 mmHg (age >65 years) 1
• Beta-blockers preferred in patients with prior MI or reduced ejection fraction 7, 1
• ACE inhibitors or ARBs for patients with diabetes, LV dysfunction, or prior MI 7, 1
• Add thiazide diuretics as needed for BP control 7
• Caution: Avoid lowering diastolic BP below 60 mmHg, which may worsen myocardial ischemia 7

4. Antianginal Medications (for symptomatic patients)

Stepwise approach 1, 8:

• First-line: Beta-blocker (e.g., metoprolol, carvedilol)
• Second-line additions if symptoms persist:
  • Long-acting calcium channel blocker (amlodipine, diltiazem, or verapamil)
  • Long-acting nitrates (isosorbide mononitrate)
  • Ranolazine
• Avoid: Combining beta-blocker with non-dihydropyridine CCB (diltiazem/verapamil) due to bradycardia and heart failure risk 7

5. Diabetes Management (if applicable)

• SGLT2 inhibitors (empagliflozin, canagliflozin, or dapagliflozin) for cardiovascular protection 1, 6
• GLP-1 receptor agonists (liraglutide or semaglutide) for additional cardiovascular benefit 1, 6
• Target HbA1c <7% while avoiding hypoglycemia 1

6. Lifestyle Modifications

• Smoking cessation (most impactful intervention) 2, 8
• Regular aerobic exercise
• Weight loss if overweight/obese
• Mediterranean-style diet

When to Add Revascularization

Revascularization (PCI or CABG) is NOT routinely superior to GDMT alone for preventing death or MI in stable CAD patients 4, 2. The COURAGE, BARI 2D, and ISCHEMIA trials consistently showed no mortality benefit from routine revascularization in stable patients with moderate-to-severe ischemia 4, 2.

Clear Indications for Revascularization:

1. Anatomic Indications (to improve survival):

• Left main disease ≥50% stenosis → CABG preferred; PCI reasonable for low-medium complexity 9
• Three-vessel disease with normal LV function → CABG may be reasonable 9
• Proximal LAD involvement with multi-vessel disease → Consider CABG 9

2. Symptomatic Indications:

• Lifestyle-limiting angina despite maximal medical therapy (≥2 antianginal drugs at optimal doses) 1
• Unstable angina or acute coronary syndrome → Urgent revascularization indicated 5

3. High-Risk Features:

• Severe LV systolic dysfunction (EF ≤35%) with viable myocardium 2
• Large area of ischemia on stress testing with high-risk anatomy 1

Revascularization Strategy Selection:

Choose CABG over PCI when:

• Left main disease with high anatomic complexity (SYNTAX score >22) 9
• Three-vessel disease, especially with diabetes 9
• Reduced LV function with multi-vessel disease 9
• Radial artery graft preferred over saphenous vein for second most important vessel after LAD 9

Choose PCI when:

• Single or two-vessel disease without proximal LAD involvement
• Left main disease with low anatomic complexity in non-surgical candidates 9
• Patient preference after shared decision-making
• Use radial artery access to reduce bleeding complications 9, 1

Critical Pitfalls to Avoid

1. Do NOT revascularize based solely on angiographic stenosis severity without either symptoms or documented ischemia—the "oculostenotic reflex" does not improve outcomes 10, 2

2. Do NOT assume revascularization prevents MI in stable patients—contemporary trials show GDMT alone is equally effective for preventing death/MI 4, 2

3. Do NOT lower diastolic BP below 60 mmHg in CAD patients—this can precipitate ischemia 7

4. Do NOT combine ACE inhibitor with ARB—no benefit and increased harm 1

5. Do NOT stop P2Y12 inhibitor prematurely after stent placement—maintain for full 12 months minimum 5

Special Populations

Elderly patients (>65 years):

• Target systolic BP 130-140 mmHg (higher than younger patients) 1
• Careful attention to medication side effects and drug interactions 1
• Drug-eluting stents preferred; radial access reduces bleeding 1

Women:

• Higher prevalence of microvascular dysfunction and vasospastic angina 3
• More likely to present with atypical symptoms (dyspnea, fatigue) 3
• Same treatment principles apply

Heart failure with CAD:

• Invasive coronary angiography recommended to assess for revascularization opportunity 2
• SGLT2 inhibitors and GLP-1 agonists provide additional benefit 1, 6

Follow-Up Strategy

• Annual clinical evaluation minimum for stable patients 2
• Assess symptom control, medication adherence, risk factor targets, and functional status 2
• Repeat stress testing only if symptoms worsen or change—not routinely 1
• Coronary CTA not recommended for routine surveillance 1

The evidence strongly supports that optimal medical therapy is the foundation for all CAD patients, with revascularization providing symptom relief in refractory cases and potential survival benefit only in specific high-risk anatomic patterns. 4, 1, 9, 2