What are the management strategies for stable vs unstable angina?

Management Strategies for Stable vs Unstable Angina

The management of angina requires different approaches based on whether it is stable or unstable, with unstable angina requiring immediate hospitalization and aggressive intervention while stable angina can be managed with a stepwise pharmacological approach and selective revascularization. 1

Stable Angina Management

Pharmacological Therapy

First-Line Medications

1. Anti-ischemic/Anti-anginal Therapy

   • Beta-blockers: First-line therapy for symptom control, especially beneficial in post-MI patients and those with LV dysfunction 1
   • Short-acting nitrates: For acute symptomatic relief of anginal episodes 1
   • Calcium channel blockers: Alternative first-line therapy when beta-blockers are contraindicated or poorly tolerated 1

2. Preventive Therapy (to reduce mortality and morbidity)

   • Aspirin: 75-150 mg daily for all patients without contraindications 1, 2
   • Statins: For all patients with coronary disease to target LDL-C <70 mg/dL 1, 2
   • ACE inhibitors: Indicated for patients with coexisting hypertension, diabetes, or LV dysfunction; should be considered in all patients with proven coronary disease 1

Second-Line Medications

• Long-acting nitrates: Added when symptoms are not controlled with beta-blockers or calcium channel blockers 1
  • Require a daily "nitrate-free" interval of 10-12 hours to prevent tolerance 2
• Combination therapy: Consider combining different classes of anti-anginal drugs when monotherapy is insufficient 1

Revascularization

• Indications for coronary arteriography: When symptoms are not satisfactorily controlled by medical therapy 1
• Percutaneous Coronary Intervention (PCI):
  • Effective for symptom relief when medical therapy fails 1
  • No evidence for mortality reduction compared to medical therapy 1, 3
• Coronary Artery Bypass Grafting (CABG):
  • Highly effective for symptom relief 1
  • Reduces mortality in specific subgroups: left main stem stenosis, proximal LAD stenosis, three-vessel disease (especially with impaired LV function) 1

Follow-up

• Evaluate every 4-6 months during first year of therapy, then annually if stable 1
• Monitor for:
  • Changes in physical activity level
  • Changes in anginal symptoms
  • Medication tolerance
  • Success in risk factor modification
  • Development of new comorbidities 1

Unstable Angina Management

Unstable angina is part of the acute coronary syndrome spectrum and requires:

Immediate Interventions

• Hospitalization for close monitoring
• Intensive anti-ischemic therapy:
  • Intravenous nitroglycerin
  • Beta-blockers (unless contraindicated)
  • Dual antiplatelet therapy (aspirin plus P2Y12 inhibitor) 2
• Early invasive strategy with coronary angiography and revascularization for high-risk patients 2

Pharmacological Therapy

• Dual antiplatelet therapy: Aspirin plus clopidogrel/ticagrelor/prasugrel 2
• Anticoagulation: Unfractionated or low-molecular-weight heparin
• High-intensity statin therapy: Started immediately 2
• Beta-blockers: To reduce heart rate and myocardial oxygen demand
• ACE inhibitors: Particularly for patients with reduced LV function, diabetes, or hypertension 2

Key Differences in Management Approach

Aspect	Stable Angina	Unstable Angina
Setting	Outpatient	Inpatient/Emergency
Urgency	Non-urgent	Urgent/emergent
Initial therapy	Oral medications	IV medications often needed
Antiplatelet	Single (aspirin)	Dual antiplatelet therapy
Revascularization	Selective, based on symptoms	Early invasive approach often indicated
Risk stratification	Exercise testing, imaging	Troponin, risk scores (TIMI, GRACE)

Special Considerations

Refractory Angina

For patients with persistent symptoms despite optimal medical therapy who are not candidates for revascularization:

• Enhanced external counterpulsation
• Spinal cord stimulation
• Transmyocardial revascularization 1, 4

Microvascular Angina

• Often affects women with normal or near-normal coronary arteries
• May account for up to 40% of angina cases
• Calcium channel blockers are first-line therapy 1

Common Pitfalls to Avoid

1. Underutilizing preventive therapies: Ensure all stable angina patients receive aspirin and statins unless contraindicated
2. Inadequate dose optimization: Optimize dosing of one drug before adding another; avoid rushing to triple therapy 1
3. Overlooking non-atherosclerotic causes: Consider microvascular dysfunction, especially in women with normal coronaries 1
4. Failing to recognize unstable angina: New-onset, worsening, or rest angina requires urgent evaluation
5. Neglecting risk factor modification: Smoking cessation, blood pressure control, and diabetes management remain essential components of therapy 2

By following these evidence-based approaches, clinicians can effectively manage both stable and unstable angina to improve symptoms, quality of life, and long-term outcomes.