What is the management of unstable angina?

Management of Unstable Angina

Patients with unstable angina should be hospitalized immediately, preferably in a coronary care unit, and receive dual antiplatelet therapy (aspirin plus clopidogrel), anticoagulation, anti-ischemic medications, and risk stratification to determine the need for early invasive coronary angiography. 1

Immediate Hospitalization and Initial Stabilization

• Admit all patients to a coronary care unit or monitored bed with continuous ECG monitoring to detect ischemia and arrhythmias 2, 1
• Place patients on bed rest while ischemia is ongoing, but mobilize to chair and bedside commode when symptom-free 2
• Provide supplemental oxygen to patients with cyanosis, respiratory distress, or high-risk features, confirming adequate arterial oxygen saturation 2

Antiplatelet Therapy

• Administer aspirin 162-325 mg immediately (or 75-150 mg if already on chronic therapy) and continue indefinitely, as this significantly reduces the risk of myocardial infarction, stroke, or death 3, 1, 4
• Start clopidogrel 75 mg daily in addition to aspirin unless urgent CABG is planned within 24 hours 1, 4
• Continue dual antiplatelet therapy with aspirin and clopidogrel for at least 12 months 1

Anticoagulation

• Begin anticoagulation with either unfractionated heparin (UFH) or low molecular weight heparin (LMWH) during the acute phase 1
• Enoxaparin is preferable to UFH unless coronary artery bypass grafting is planned within 24 hours 1

Anti-Ischemic Therapy

Beta-Blockers

• Administer intravenous beta-blockers to hemodynamically stable patients, followed by oral maintenance therapy 2, 1
• Do NOT give IV beta-blockers to patients with contraindications to beta blockade, signs of heart failure, low-output state, or risk factors for cardiogenic shock, as this may be harmful 2

Nitrates

• Use intravenous nitroglycerin for acute management of ongoing ischemia, followed by long-acting nitrates for maintenance therapy 2, 1
• Provide short-acting nitroglycerin for immediate symptom relief with proper usage instructions 1

Calcium Channel Blockers

• Consider non-dihydropyridine calcium channel blockers (verapamil or diltiazem) as initial therapy in the absence of severe LV dysfunction or contraindications 2

ACE Inhibitors/ARBs

• Administer ACE inhibitor orally within first 24 hours if pulmonary congestion present or LVEF ≤0.40, in the absence of hypotension (systolic BP <100 mm Hg or <30 mm Hg below baseline) 2
• Use ARB if ACE inhibitor intolerant and patient has heart failure signs or LVEF ≤0.40 2

Risk Stratification

High-Risk Features (Requiring Early Invasive Strategy)

• Recurrent ischemia despite intensive medical therapy 2, 1
• Elevated cardiac biomarkers (troponin) 1
• ST-segment deviation ≥0.05 mV or new bundle-branch block 2
• Hemodynamic instability or depressed LV function (LVEF <0.40) 2, 1
• Serious ventricular arrhythmias 2, 1
• Heart failure symptoms, S3 gallop, or new/worsening mitral regurgitation 2
• Early post-infarction unstable angina 1

Low-Risk Features (Conservative Strategy Appropriate)

• Absence of rest pain or nocturnal pain 3
• Normal or unchanged ECG 3
• No troponin elevation 3
• No rest pain within 12 hours 2

Invasive vs. Conservative Strategy

Early Invasive Strategy (Preferred for Intermediate-High Risk)

• Perform routine coronary angiography within 48 hours followed by revascularization for intermediate to high-risk patients 1
• 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
• Emergency or urgent cardiac catheterization is indicated for patients with ongoing ischemia refractory to initial medical therapy or hemodynamic instability 2

Conservative Strategy (For Low-Risk Patients)

• Initially conservative (invasive selective) strategy is appropriate for low-risk patients 3
• Perform noninvasive stress testing after stabilization 2
• Reserve invasive intervention for failure of optimal medical therapy or objective evidence of ischemia 2, 3

Revascularization Options

Percutaneous Coronary Intervention (PCI)

• Consider PCI for appropriate coronary anatomy in intermediate-high risk patients 1
• Use bare metal stents or balloon angioplasty if non-cardiac surgery is planned soon after intervention 1

Coronary Artery Bypass Grafting (CABG)

• CABG is strongly preferred for:
  • Significant left main disease 1
  • Three-vessel disease, particularly with depressed LV function 1
  • Diabetic patients with multivessel disease 1

Lipid Management

• Initiate high-intensity statin therapy before hospital discharge for all patients 1
• Early statin initiation improves outcomes and increases long-term adherence 1
• Target LDL cholesterol <100 mg/dL 1
• The MIRACL trial showed that atorvastatin 80 mg daily started 24-96 hours after acute coronary syndrome reduced the composite endpoint from 17.4% to 14.8% at 16 weeks 2
• Consider fibrate or niacin if HDL cholesterol <40 mg/dL 2

Medications to AVOID

• Do NOT administer NSAIDs (except aspirin), whether nonselective or COX-2-selective, during hospitalization due to increased risks of mortality, reinfarction, hypertension, heart failure, and myocardial rupture 2

Long-Term Management and Secondary Prevention

Pharmacotherapy

• Continue aspirin 75-150 mg daily indefinitely 1
• Maintain beta-blocker therapy long-term, particularly in post-MI patients 1
• Continue statin therapy for all patients with coronary disease 1
• Consider ACE inhibitors for patients with LV dysfunction, hypertension, or diabetes 1

Lifestyle Modifications

• Smoking cessation with referral to cessation programs 1
• Weight optimization and daily exercise 1
• Dietary modifications 2
• Tight glucose control in diabetic patients 1
• Control of hypertension 2

Follow-Up Strategy

• High-risk patients should return in 1-2 weeks 1
• Low-risk medically treated or revascularized patients should return in 2-6 weeks 1
• Perform serial cardiac biomarker assessments (troponin) during hospitalization 3

Common Pitfalls to Avoid

• Do not delay aspirin administration while awaiting diagnostic confirmation 1
• Do not give IV beta-blockers to patients with signs of heart failure or cardiogenic shock risk 2
• Do not withhold early invasive strategy from women at high or intermediate risk with obstructed coronary arteries suitable for revascularization, despite some conflicting trial data 2
• Do not discharge patients on intensive medical therapy without initiating statin therapy, as in-hospital initiation dramatically increases long-term adherence (from 10% to 91% in the CHAMP study) 2