What is the initial management of unstable angina in the emergency department?

Initial Management of Unstable Angina in the Emergency Department

Immediately place the patient on continuous cardiac monitoring with bed/chair rest, administer aspirin 162-325 mg (non-enteric coated, chewed), initiate anticoagulation, and begin risk stratification to determine timing of invasive strategy. 1, 2

Immediate Stabilization (First 10 Minutes)

Monitoring and Positioning

• Place patient on continuous ECG monitoring and enforce bed/chair rest to detect arrhythmias and reduce myocardial oxygen demand 1
• Obtain 12-lead ECG immediately to rule out ST-elevation MI requiring different management pathway 1

Oxygen Therapy

• Administer supplemental oxygen only if arterial oxygen saturation is <90%, respiratory distress, or high-risk features for hypoxemia (use pulse oximetry for continuous monitoring) 1, 2
• Avoid routine oxygen in normoxic patients as it provides no benefit 2

Antiplatelet Therapy

• Administer aspirin 162-325 mg immediately (non-enteric coated, chewed for faster buccal absorption) unless documented allergy 1, 2, 3
• Continue aspirin 75-100 mg daily indefinitely 2, 3
• Add a P2Y12 inhibitor before diagnostic angiography (upstream administration): ticagrelor 180 mg loading dose (then 90 mg twice daily) is preferred, or clopidogrel 300-600 mg loading dose (then 75 mg daily) 2, 3

Anticoagulation

• Initiate parenteral anticoagulation immediately in all patients with unfractionated heparin (bolus 5,000 U followed by infusion of 1,000 U/h titrated to APTT approximately 2 times control) or enoxaparin 1, 2, 3
• For early invasive strategy, use unfractionated heparin or enoxaparin; fondaparinux is preferred for conservative strategy due to lower bleeding risk 2

Symptom Management

Nitroglycerin Administration

• For ongoing ischemic chest discomfort, give sublingual nitroglycerin 0.4 mg every 5 minutes for maximum of 3 doses 1
• After 3 sublingual doses, assess need for intravenous nitroglycerin if pain persists 1
• Intravenous nitroglycerin is indicated in first 48 hours for persistent ischemia, heart failure, or hypertension 1
• Contraindications to nitroglycerin: systolic blood pressure <90 mmHg, severe bradycardia or tachycardia, right ventricular infarction, or phosphodiesterase inhibitor use within 24-48 hours 2, 3

Pain Control

• If chest discomfort persists despite nitroglycerin, administer morphine sulfate intravenously (2-4 mg doses) 1, 2
• Use morphine cautiously as it may delay P2Y12 inhibitor absorption 2

Pharmacologic Therapy (Within First 24 Hours)

Beta-Blockers

• Initiate oral beta-blocker therapy within first 24 hours unless patient has signs of heart failure, evidence of low-output state, increased risk for cardiogenic shock, or contraindications (PR interval >0.24 seconds, second or third degree heart block, active asthma/reactive airway disease) 1, 2, 3
• Risk factors for cardiogenic shock include: age >70 years, systolic blood pressure <120 mmHg, sinus tachycardia >110 or heart rate <60, increased time since symptom onset 1
• For hypertensive patients without contraindications, intravenous beta-blockers at presentation are reasonable 1

Calcium Channel Blockers

• For continuing or frequently recurring ischemia when beta-blockers are contraindicated, use nondihydropyridine calcium channel blocker (verapamil or diltiazem) in absence of clinically significant left ventricular dysfunction 1
• Never use immediate-release dihydropyridine calcium channel blockers (nifedipine) without adequate beta-blockade 2, 3

ACE Inhibitors/ARBs

• Administer ACE inhibitor orally within first 24 hours to patients with pulmonary congestion or left ventricular ejection fraction ≤0.40, unless hypotensive (systolic blood pressure <100 mmHg or <30 mmHg below baseline) 1, 2, 3
• Use angiotensin receptor blocker for ACE inhibitor-intolerant patients with heart failure or LVEF ≤0.40 1, 2, 3

Risk Stratification and Management Strategy Selection

Immediate Risk Assessment

• Perform immediate risk stratification using GRACE or TIMI score to determine timing of invasive strategy 2, 3
• High-risk features include: refractory angina, hemodynamic instability, electrical instability, elevated cardiac troponin with high-risk features, symptoms at rest >20 minutes, recent syncope/presyncope 1, 2, 3

Invasive Strategy Timing

• Early invasive strategy (angiography within 12-24 hours) is mandatory for high-risk patients (GRACE score >140) 1, 2, 3
• For initially stabilized high-risk patients, early invasive strategy (within 12-24 hours) is superior to delayed approach 1
• Conservative strategy (selective invasive) may be considered only for low-to-intermediate risk patients who are initially stabilized 1, 2, 3

GP IIb/IIIa Inhibitors

• Consider eptifibatide or tirofiban upstream (before angiography) in very high-risk patients, particularly if delay to catheterization is anticipated 2, 4
• Do not give abciximab upstream; use only if PCI is imminent with no delay to angiography 2

Critical Pitfalls to Avoid

Medications to Discontinue

• Discontinue all NSAIDs (except aspirin) immediately due to increased risks of mortality, reinfarction, hypertension, heart failure, and myocardial rupture 1, 2, 3
• Avoid omeprazole and esomeprazole with clopidogrel due to reduced antiplatelet effect; use other PPIs if gastroprotection needed 2

Management Errors

• Do not delay angiography in high-risk patients for "medical stabilization" as early invasive approach (within 24 hours) reduces ischemic events 1, 2
• Do not administer routine supplemental oxygen to normoxic patients 2
• Recognize that women and elderly patients frequently present atypically with dyspnea, fatigue, or nausea rather than classic chest pain 1, 5