What is the treatment for unstable angina?

Treatment of Unstable Angina

Patients with unstable angina should be hospitalized immediately in a coronary care unit and started on aspirin 75-150 mg daily, intravenous beta-blockers (if hemodynamically stable), anticoagulation with low molecular weight heparin (preferably enoxaparin unless CABG planned within 24 hours), and short-acting nitroglycerin for symptom relief. 1, 2

Immediate Hospitalization and Monitoring

• All patients with suspected unstable angina require immediate hospitalization, preferably in a coronary care unit, for close monitoring and aggressive treatment 1, 2
• This is critical because unstable angina represents an acute coronary syndrome that can rapidly progress to myocardial infarction or death 1

Initial Pharmacological Management

Antiplatelet Therapy (Highest Priority)

• Aspirin 75-150 mg daily should be administered immediately as it significantly reduces the risk of myocardial infarction, stroke, or death by 5.5% (number needed to treat = 15) 3, 1, 2
• Add clopidogrel 75 mg daily in addition to aspirin, unless urgent CABG is planned within 24 hours 1
• Continue dual antiplatelet therapy (aspirin + clopidogrel) for at least 12 months 1

Beta-Blockers

• Start intravenous beta-blockers in hemodynamically stable patients, followed by oral maintenance therapy 1, 2
• Beta-selective agents without intrinsic sympathomimetic activity are preferred 2
• Do not abruptly discontinue beta-blockers in patients with coronary artery disease, as this can cause severe exacerbation of angina, myocardial infarction, and ventricular arrhythmias 4
• When discontinuing is necessary, taper gradually over 1-2 weeks with careful monitoring 4

Anticoagulation

• Begin anticoagulation with low molecular weight heparin (LMWH) or unfractionated heparin (UFH) 1, 2
• Enoxaparin is preferable to UFH unless CABG is planned within 24 hours 1

Nitrates

• Provide short-acting nitroglycerin for immediate symptom relief with proper usage instructions 1, 2
• Use intravenous nitroglycerin for acute management, followed by long-acting nitrates for maintenance therapy 2
• Ensure a daily "nitrate-free" interval when using long-acting nitrates to avoid tolerance 2

Statins

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

Risk Stratification

High-Risk Features (Requiring Early Invasive Strategy)

• Recurrent ischemia despite optimal medical therapy 1, 2
• Elevated cardiac biomarkers (troponin) 2
• Hemodynamic instability 1, 2
• Major arrhythmias 1, 2
• Early post-infarction unstable angina 1, 2

Invasive Management

• For intermediate to high-risk patients, perform early coronary angiography within 48 hours followed by revascularization 1, 2
• The TACTICS-TIMI 18 trial demonstrated that early invasive strategy reduced death, MI, or rehospitalization at 6 months (15.9% vs 19.4%) compared to conservative strategy 1
• If symptoms persist despite optimal medical therapy, coronary angiography followed by appropriate revascularization (PCI or CABG) is indicated 2

Revascularization Decision-Making

Percutaneous Coronary Intervention (PCI)

• Use bare metal stents or balloon angioplasty when non-cardiac surgery is planned soon after intervention 1
• PCI is appropriate for patients with anatomically suitable lesions and persistent symptoms 1

Coronary Artery Bypass Grafting (CABG)

• CABG should be performed for significant left main disease, three-vessel disease (particularly with depressed left ventricular function), or diabetic patients with multivessel disease 1
• CABG improves both prognosis and symptom relief in these high-risk anatomic subsets 1

Long-Term Management (After Stabilization)

Antiplatelet Therapy

• Continue aspirin 75-150 mg daily indefinitely 1, 2
• After 18 months of aspirin therapy, patients with history of unstable angina should be treated according to stable angina recommendations (aspirin 75 mg daily continued long-term) 3

Other Medications

• Maintain beta-blocker therapy long-term, particularly in post-MI patients 1, 2
• Continue statin therapy for all patients with coronary disease 1, 2
• Consider ACE inhibitors for patients with left ventricular dysfunction, hypertension, or diabetes 1

Critical Pitfalls to Avoid

• Never use immediate-release or short-acting dihydropyridine calcium antagonists as they may increase adverse cardiac events 2
• Do not abruptly discontinue beta-blockers, as this can precipitate severe angina exacerbation, MI, or ventricular arrhythmias 4
• Avoid combining verapamil or diltiazem with beta-blockers in patients with heart failure due to negative inotropic effects 5
• Do not routinely withdraw chronically administered beta-blocking therapy prior to major surgery 4
• In patients with bronchospastic disease requiring beta-blockers, use the lowest possible dose and ensure bronchodilators are readily available 4
• In pheochromocytoma, beta-blockers must be given only after alpha-blocker initiation to avoid paradoxical hypertension 4