What are the differences in management and treatment between unstable angina and stable angina?

Management Differences Between Unstable and Stable Angina

Unstable angina requires immediate hospitalization with aggressive antiplatelet therapy, anticoagulation, and early invasive management, while stable angina can be managed primarily with outpatient medical therapy and selective invasive evaluation based on risk stratification. 1

Clinical Presentation and Diagnosis

• Unstable angina presents as: (1) rest angina lasting up to 20 minutes, (2) rapidly increasing crescendo angina over 4 weeks or less, or (3) new onset severe angina within 2 months of initial presentation 2
• Stable angina is characterized by predictable chest discomfort with exertion or emotional stress that is relieved by rest and/or nitroglycerin, with a consistent pattern over time 2
• Unstable angina is part of the acute coronary syndrome spectrum, sharing a common pathophysiological mechanism with myocardial infarction involving plaque rupture or erosion 2
• ECG changes in unstable angina include ST-segment depression or T-wave inversion, while stable angina may have normal ECG at rest with changes only during stress 2

Initial Management Approach

Unstable Angina

• Immediate hospitalization with continuous ECG monitoring for ischemia and arrhythmia detection 2, 1
• Aggressive antiplatelet therapy including aspirin 75-325 mg/day and P2Y12 inhibitors 2, 1
• Anticoagulation with unfractionated heparin or low-molecular-weight heparin (enoxaparin preferred) 2, 1
• Early risk stratification using clinical criteria, ECG changes, and cardiac biomarkers (troponin) 2, 1
• Early invasive strategy with coronary angiography within 24-48 hours for high and intermediate-risk patients 2

Stable Angina

• Outpatient evaluation and management with risk factor modification 2
• Symptom control with anti-anginal medications (beta-blockers, calcium channel blockers, nitrates) 2
• Non-invasive testing for diagnosis and risk stratification (exercise ECG, stress imaging) 2
• Selective coronary angiography based on symptom severity, risk factors, and non-invasive test results 2

Pharmacological Management

Unstable Angina

• Dual antiplatelet therapy (aspirin plus P2Y12 inhibitor) is mandatory 2, 1
• Anticoagulation with heparin products until revascularization or clinical stabilization 2
• Early initiation of high-intensity statin therapy 2, 1
• Beta-blockers for all patients without contraindications 2, 3
• Consider glycoprotein IIb/IIIa inhibitors in high-risk patients undergoing PCI 2

Stable Angina

• Aspirin 75-100 mg daily for all patients without contraindications 2
• Beta-blockers as first-line anti-anginal therapy 2, 3
• Calcium channel blockers or long-acting nitrates as alternatives or add-on therapy 2
• Statins for all patients regardless of baseline lipid levels 2
• Consider ranolazine for patients with persistent symptoms despite other anti-anginal medications 4, 2

Revascularization Strategy

Unstable Angina

• Early invasive strategy (24-48 hours) recommended for most patients 2
• Immediate invasive approach (<2 hours) for very high-risk features (refractory angina, hemodynamic instability) 2
• PCI with stenting plus dual antiplatelet therapy is the preferred approach 2
• CABG for patients with left main disease, complex multivessel disease, or diabetes with multivessel disease 2

Stable Angina

• Revascularization considered when symptoms are not adequately controlled with optimal medical therapy 2
• Decision based on coronary anatomy, symptom severity, and objective evidence of ischemia 2
• PCI primarily for symptom relief rather than mortality benefit in most patients 2
• CABG preferred for complex multivessel disease, left main disease, or diabetic patients with multivessel disease 2

Follow-up and Long-term Management

Unstable Angina

• Close follow-up after discharge (high-risk patients within 1-2 weeks) 1
• Dual antiplatelet therapy for at least 12 months after PCI 2
• Aggressive secondary prevention with risk factor modification 2, 1
• Long-term beta-blocker therapy, particularly after MI 2, 3

Stable Angina

• Regular outpatient follow-up to assess symptom control and optimize medical therapy 2
• Periodic reassessment of risk and consideration for revascularization if symptoms worsen 2
• Lifelong aspirin and statin therapy 2
• Strict control of risk factors (diabetes, hypertension, smoking) 2

Common Pitfalls and Caveats

• Failure to recognize unstable angina as a medical emergency requiring immediate hospitalization 1
• Delaying antiplatelet therapy in unstable angina patients 1
• Abrupt discontinuation of beta-blockers in patients with coronary artery disease, which can precipitate worsening angina or MI 3
• Inadequate risk stratification in patients with chest pain 1
• Overlooking the importance of secondary prevention measures in both conditions 2, 1
• Treating all angina patients with the same approach rather than tailoring therapy based on risk profile 2