What is the initial management of a patient presenting with unstable angina to the Emergency Room?

Initial Management of Unstable Angina in the Emergency Room

Patients presenting with unstable angina to the Emergency Room should receive immediate oxygen supplementation, continuous ECG monitoring, aspirin (162-325 mg chewed), sublingual nitroglycerin, and intravenous access, followed by risk stratification to determine the timing of invasive management. 1

Immediate Assessment and Stabilization

First Steps (0-10 minutes)

• Place patient on cardiac monitor immediately with emergency resuscitation equipment nearby
• Obtain 12-lead ECG within 10 minutes of arrival 1
• Establish IV access
• Administer oxygen if:
  • SaO2 < 90%
  • Respiratory distress present
  • Cyanosis present
  • High-risk features present 1
• Obtain vital signs and brief focused history

Initial Pharmacological Management

1. Antiplatelet therapy:

   • Administer aspirin 162-325 mg (chewed, non-enteric coated) immediately 1, 2
   • Consider P2Y12 inhibitor (ticagrelor preferred over clopidogrel) 2

2. Anti-ischemic therapy:

   • Administer sublingual nitroglycerin (0.4 mg) every 5 minutes for a maximum of 3 doses 1
   • If pain persists, initiate IV nitroglycerin (starting at 10 μg/min, titrating up to 200 μg/min) 1
   • Avoid in patients with:
     • Systolic BP < 90 mmHg or > 30 mmHg below baseline
     • Severe bradycardia or tachycardia
     • Right ventricular infarction
     • Recent use of phosphodiesterase-5 inhibitors 1

3. Anticoagulation:

   • Initiate parenteral anticoagulation with one of:
     • Enoxaparin (1 mg/kg SC every 12 hours)
     • Unfractionated heparin (60-70 U/kg IV bolus [max 5000 U] followed by 12-15 U/kg/hr [max 1000 U/hr]) 1, 2
     • Fondaparinux (2.5 mg SC daily) 2

4. Beta-blockers:

   • Administer oral beta-blockers within first 24 hours unless contraindicated
   • Avoid IV beta-blockers in patients with:
     • Signs of heart failure
     • Low cardiac output
     • Risk factors for cardiogenic shock 1

Risk Stratification and Triage

High-Risk Features (Requiring Immediate Attention)

• Ongoing or recurrent chest pain despite initial therapy
• Hemodynamic instability
• Dynamic ST-segment changes (≥0.5 mm depression or transient elevation)
• Elevated cardiac troponin levels
• Signs of heart failure (S3 gallop, pulmonary edema)
• New or worsening mitral regurgitation
• Sustained ventricular arrhythmias 1

Triage Decision

1. Very high-risk patients (hemodynamic instability, refractory angina):

   • Admit to Coronary Care Unit
   • Immediate invasive strategy (<2 hours) 2
   • Consider glycoprotein IIb/IIIa inhibitors (eptifibatide, tirofiban) 3

2. High-risk patients (elevated troponin, dynamic ECG changes):

   • Admit to Coronary Care Unit
   • Early invasive strategy (<24 hours) 2

3. Intermediate-risk patients:

   • Admit to cardiology ward
   • Invasive strategy within 72 hours 2

4. Low-risk patients:

   • Consider chest pain unit observation
   • Serial ECGs and cardiac biomarkers
   • Non-invasive stress testing before discharge 1, 4

Common Pitfalls and Caveats

• Delayed diagnosis: Do not wait for troponin elevation to initiate treatment; unstable angina may not show troponin elevation initially 2
• Inadequate monitoring: All patients require continuous ECG monitoring as ventricular fibrillation is a major preventable cause of death 1
• Overuse of oxygen: Routine oxygen is not necessary in normoxemic patients but is reasonable during initial stabilization 1
• Inappropriate use of NSAIDs: Avoid all NSAIDs (except aspirin) due to increased risk of mortality, reinfarction, and heart failure 1
• Delayed invasive management: Patients with ongoing symptoms despite medical therapy require urgent angiography rather than prolonged medical stabilization 2
• Overlooking atypical presentations: Elderly patients and women may present with atypical symptoms such as dyspnea, nausea, or fatigue rather than classic chest pain 1

By following this structured approach to the initial management of unstable angina, emergency physicians can rapidly stabilize patients, initiate appropriate therapy, and determine the optimal timing for invasive management, thereby reducing morbidity and mortality.