What is the treatment for unstable angina?

Treatment of Unstable Angina

All patients with unstable angina should be hospitalized immediately, preferably in a coronary care unit, and receive aspirin, anticoagulation, beta-blockers, and nitroglycerin as initial therapy, followed by risk stratification to determine whether an early invasive strategy with coronary angiography is needed. 1, 2

Immediate Management Upon Presentation

Initial Stabilization and Monitoring

• Hospitalize immediately in a coronary care unit with continuous ECG monitoring for ischemia and arrhythmia detection 1, 2, 3
• Administer supplemental oxygen if arterial saturation is <90% or respiratory distress is present 3
• Provide sublingual nitroglycerin for immediate symptom relief with proper usage instructions 1, 2

Core Pharmacological Therapy (Start Immediately)

Antiplatelet Therapy:

• Aspirin 162-325 mg loading dose immediately, then 75-150 mg daily indefinitely—this significantly reduces risk of myocardial infarction, stroke, or death by 5.5% 1, 2, 3
• Clopidogrel 75 mg daily should be added unless urgent CABG is planned within 24 hours 4, 1, 3

Anticoagulation:

• Enoxaparin (low molecular weight heparin) is preferred over unfractionated heparin unless CABG is planned within 24 hours 1
• Alternative options include unfractionated heparin, fondaparinux, or bivalirudin based on institutional protocols 1, 3

Beta-Blockers:

• Administer intravenously in hemodynamically stable patients without contraindications (avoid in asthma, symptomatic peripheral vascular disease, or first-degree heart block) 1, 2
• Transition to oral maintenance therapy during hospitalization 1, 2

Nitrates:

• Intravenous nitroglycerin for acute symptom management and ongoing ischemia 1, 2, 3
• Transition to long-acting nitrates for maintenance, ensuring a daily "nitrate-free" interval to prevent tolerance 2

Statins:

• Initiate high-intensity statin therapy before hospital discharge—early initiation improves outcomes and increases long-term adherence 4, 1

Risk Stratification (Perform Within First 24 Hours)

High-Risk Features Requiring Early Invasive Strategy

Patients with any of the following should undergo coronary angiography within 4-48 hours 4, 1, 3:

• Recurrent angina/ischemia at rest or with low-level activity despite intensive medical therapy 4
• Elevated troponin T or troponin I 4, 1
• New or presumably new ST-segment depression 4
• Hemodynamic instability 4, 1
• Sustained ventricular tachycardia or major arrhythmias 4, 1
• Recurrent ischemia with heart failure symptoms, S3 gallop, pulmonary edema, or new/worsening mitral regurgitation 4
• Depressed left ventricular systolic function (ejection fraction <0.40) 4
• PCI within 6 months or prior CABG 4

Early Invasive vs. Conservative Strategy

• High-risk patients: Early invasive strategy with routine coronary angiography within 48 hours followed by revascularization reduces death, MI, or rehospitalization (15.9% vs 19.4% at 6 months) 1
• Lower-risk patients: Initial conservative strategy with invasive evaluation only if symptoms persist despite optimal medical therapy or objective evidence of ischemia develops 4, 3

Revascularization Decision-Making

Percutaneous Coronary Intervention (PCI)

• Indicated for single or multi-vessel disease amenable to PCI in high-risk patients 1
• Use bare metal stents if non-cardiac surgery is planned soon after intervention 1
• Diabetic patients with single-vessel disease and inducible ischemia may benefit from PCI 4

Coronary Artery Bypass Grafting (CABG)

• Strongly preferred for significant left main disease, three-vessel disease (especially with depressed LV function), or diabetic patients with multivessel disease 4, 1
• Use internal mammary arteries when possible, as this improves survival and reduces late complications 4
• Discontinue clopidogrel 5-7 days before elective CABG 3

Long-Term Management and Secondary Prevention

Mandatory Long-Term Medications

• Aspirin 75-150 mg daily indefinitely 4, 1, 2
• Beta-blockers continued long-term, particularly in post-MI patients 4, 1, 2
• Statins for all patients with coronary disease, targeting LDL <100 mg/dL (ideally <70 mg/dL) 4, 1
• ACE inhibitors for patients with heart failure, LV dysfunction (EF <0.40), hypertension, or diabetes 4, 1
• Clopidogrel 75 mg daily for at least 12 months if PCI performed 1

Lifestyle Modifications

• Smoking cessation with referral to cessation programs 4
• Tight glucose control in diabetic patients 4
• Weight optimization and daily exercise 4

Critical Pitfalls to Avoid

• Never administer fibrinolytic therapy to patients with unstable angina/NSTEMI without ST-segment elevation 3
• Avoid immediate-release or short-acting dihydropyridine calcium antagonists (e.g., short-acting nifedipine) as they may increase adverse cardiac events 2
• Do not delay treatment while waiting for cardiac biomarker results—initial management should be based on clinical presentation 3
• Do not discharge prematurely—observe for at least 6-12 hours with serial ECGs and cardiac biomarkers 3
• Ensure nitrate-free intervals when using long-acting nitrates to prevent tolerance 2

Follow-Up Strategy

• High-risk patients: Return in 1-2 weeks 4
• Low-risk medically treated or revascularized patients: Return in 2-6 weeks 4
• Patients with recurrent unstable angina or severe chronic stable angina despite medical management should undergo coronary arteriography 4