What is the recommended treatment for a patient presenting with unstable angina?

Treatment of Unstable Angina

Patients with unstable angina should receive immediate aspirin 75-150 mg daily, dual antiplatelet therapy with clopidogrel, intravenous beta-blockers, anticoagulation with heparin, and be hospitalized in a coronary care unit for close monitoring, with high-risk patients requiring early invasive coronary angiography within 48 hours. 1, 2

Immediate Management

Hospitalization and Monitoring

• All patients with suspected unstable angina must be hospitalized, preferably in a coronary care unit, for continuous ECG monitoring and aggressive treatment 1, 2
• Patients with chest pain persisting >20 minutes despite sublingual nitroglycerin require immediate admission 3

Initial Pharmacotherapy (Start Immediately)

Antiplatelet Therapy:

• Aspirin 75-150 mg should be administered immediately and continued indefinitely - this provides a 6.6% absolute risk reduction in MI, stroke, or vascular death (number needed to treat = 15) 4, 1
• Clopidogrel 75 mg daily should be added to aspirin and continued for at least 12 months unless urgent CABG is planned within 24 hours 4, 2
• The CURE trial demonstrated a 20% reduction in cardiac death, MI, or stroke with dual antiplatelet therapy 4

Beta-Blockers:

• Administer intravenous beta-blockers initially (e.g., metoprolol 5 mg IV every 5 minutes for total 15 mg), followed by oral maintenance therapy 4, 1
• Beta-blockade reduces progression to MI by 13% 4
• Contraindications include ongoing heart failure, hemodynamic instability, or bronchospasm 4

Anticoagulation:

• Start either unfractionated heparin (5,000 U bolus, then 1,000 U/h titrated to APTT 2x control) or low molecular weight heparin immediately 4, 1
• Enoxaparin is preferable to unfractionated heparin unless CABG is planned within 24 hours 2, 5

Nitrates:

• Give sublingual nitroglycerin 0.4 mg every 5 minutes for up to 3 doses for immediate symptom relief 4, 1
• If symptoms persist after 3 sublingual doses, start continuous intravenous nitroglycerin and titrate to symptom relief or blood pressure response 4, 5
• Transition to oral or topical nitrates after 24 hours to avoid tolerance 4

Morphine:

• Administer morphine sulfate 1-5 mg IV for symptoms not relieved after 3 sublingual nitroglycerin tablets or for recurrent pain despite therapy 4
• Repeat every 5-30 minutes as needed with careful blood pressure monitoring 4

Risk Stratification (Within First 8-12 Hours)

High-Risk Features Requiring Early Invasive Strategy: 4, 1, 2

• Recurrent ischemia (chest pain or dynamic ST-segment changes, particularly ST depression or transient ST elevation)
• Elevated troponin levels
• Hemodynamic instability (hypotension, pulmonary edema)
• Major arrhythmias (ventricular tachycardia, ventricular fibrillation)
• Early post-infarction unstable angina

Invasive Management for High-Risk Patients

GP IIb/IIIa Inhibitors:

• Add a GP IIb/IIIa inhibitor (tirofiban, eptifibatide, or abciximab) in high-risk patients when cardiac catheterization and PCI are planned 4, 2
• The PRISM-PLUS trial showed 32% risk reduction in death, MI, and refractory ischemia at 7 days with tirofiban plus heparin versus heparin alone 6
• Continue for 12-24 hours after PCI 4

Coronary Angiography:

• Perform coronary angiography within 48 hours for all intermediate to high-risk patients 2
• The TACTICS-TIMI 18 trial demonstrated that early invasive strategy reduced death, MI, or rehospitalization (15.9% vs 19.4%) compared to conservative strategy 2

Revascularization Decision:

• Left main or three-vessel disease (especially with LV dysfunction): CABG is strongly preferred 4, 2, 7
• Single-vessel disease: PCI of culprit lesion is first choice 4
• Double-vessel disease: either PCI or CABG may be appropriate depending on anatomy, comorbidities, and patient preference 4

Additional Therapies

ACE Inhibitors:

• Start ACE inhibitors for patients with LV systolic dysfunction, heart failure, diabetes, or persistent hypertension despite nitrates and beta-blockers 4, 2
• Can be initiated in ED but not mandatory in this setting 4

Statins:

• Initiate high-intensity statin therapy before hospital discharge regardless of baseline LDL cholesterol 4, 2
• The CHAMP study showed in-hospital statin initiation increased 1-year treatment rates from 10% to 91% 4
• Target LDL cholesterol <100 mg/dL 4, 2

Critical Pitfalls to Avoid

• Never use short-acting dihydropyridine calcium channel blockers (e.g., immediate-release nifedipine) without concurrent beta-blockade - these increase adverse outcomes 4, 1
• Do not administer thrombolytic therapy - it is not beneficial and potentially harmful in unstable angina without ST-elevation 7, 5
• Avoid nitrate tolerance by ensuring a daily nitrate-free interval when using long-acting nitrates 1
• Withhold clopidogrel for 5-7 days if elective CABG is planned 5

Long-Term Management (Post-Discharge)

• Aspirin 75 mg daily indefinitely 1, 2
• Clopidogrel 75 mg daily for at least 12 months 2
• Beta-blockers continued indefinitely 2
• Statins continued indefinitely with LDL goal <100 mg/dL 4, 2
• ACE inhibitors for LV dysfunction, hypertension, or diabetes 2
• Smoking cessation, weight optimization, daily exercise, and tight glucose control in diabetics 2