What is the initial management of a patient presenting with chest discomfort suggestive of angina pectoris?

Initial Management of Angina Pectoris

For patients presenting with chest discomfort suggestive of angina pectoris, obtain a 12-lead ECG within 10 minutes of arrival, measure cardiac-specific troponin immediately, and initiate aspirin 75-325 mg unless contraindicated. 1, 2

Immediate Assessment (First 10 Minutes)

Critical Actions

• Perform 12-lead ECG within 10 minutes and compare to prior tracings if available to differentiate ST-elevation MI (requiring immediate reperfusion) from non-ST-elevation acute coronary syndrome 1, 3
• Place patient on continuous cardiac monitoring with defibrillator nearby, as sudden ventricular fibrillation is the major preventable cause of early death 1, 2
• Measure cardiac-specific troponin (preferred over CK-MB or other markers) as the initial biomarker 1
• Administer aspirin 75-325 mg immediately (chewed for faster absorption) unless contraindicated 1, 2

Symptom Relief

• Give sublingual nitroglycerin 0.4 mg every 5 minutes for up to 3 doses for immediate symptom relief 2, 4
• If chest pain persists after 3 tablets over 15 minutes, this indicates high-risk acute coronary syndrome requiring hospital admission 1, 4
• Administer supplemental oxygen only if arterial saturation <90% confirmed by pulse oximetry 1, 3, 2

Risk Stratification (Within First Hour)

High-Risk Features Requiring Immediate Hospital Admission

Patients with any of the following must be admitted to the hospital immediately 1:

• Ongoing chest pain despite nitroglycerin (>20 minutes duration)
• ST-segment depression ≥0.05 mV or T-wave inversions ≥0.2 mV on ECG 1
• Elevated cardiac troponin levels (indicating NSTEMI rather than unstable angina) 1
• Hemodynamic instability (hypotension, new heart failure, pulmonary edema) 1, 2
• Major arrhythmias (repetitive ventricular tachycardia, ventricular fibrillation) 1
• Diabetes mellitus with any ischemic symptoms 1

Intermediate/Low-Risk Features Requiring Observation

Patients who are pain-free at presentation, have normal or nondiagnostic ECG, and normal initial troponin are candidates for observation in a chest pain unit or emergency department 1:

• Repeat ECG at 15-30 minute intervals if patient remains symptomatic or high clinical suspicion persists 1
• Repeat troponin measurement at 6-12 hours after symptom onset (not just after arrival) 1
• Observation period typically 6-12 hours but may extend to 24 hours depending on institutional protocols 1

Pharmacological Management for Confirmed ACS

Antiplatelet Therapy

• Continue aspirin 75-150 mg daily indefinitely 1, 2
• Add clopidogrel loading dose 300-600 mg, then 75 mg daily for 12 months 3, 2
• Consider ticagrelor as preferred P2Y12 inhibitor for moderate-to-high risk patients 3

Anticoagulation (Choose One)

• Enoxaparin 1 mg/kg subcutaneously every 12 hours (preferred for conservative management, lower risk of heparin-induced thrombocytopenia) 2
• Fondaparinux 2.5 mg subcutaneously once daily (associated with less bleeding than enoxaparin) 2
• Unfractionated heparin (if early invasive strategy planned) 1, 2

Anti-Ischemic Therapy

• Start oral beta-blocker promptly targeting heart rate 50-60 beats per minute unless contraindicated 1, 2
• Initiate intravenous nitroglycerin 5-10 mcg/min for ongoing ischemia or hypertension, titrating by 10 mcg/min every 3-5 minutes 2
• Add calcium channel blocker (dihydropyridine family) if symptoms persist despite beta-blocker and nitrates 1

Additional Mortality-Reducing Therapies

• Initiate high-intensity statin therapy immediately regardless of baseline LDL cholesterol 3, 2
• Start ACE inhibitor if patient has anterior MI, persistent hypertension, left ventricular dysfunction, heart failure, or diabetes 2

Disposition Decision Algorithm

Discharge Criteria (After Observation Period)

Patients may be discharged if all of the following are met 1:

• Pain-free throughout observation period
• Normal or unchanged ECG on serial tracings
• Normal cardiac biomarkers at 6-12 hours after symptom onset
• Negative stress test (treadmill, stress echo, or nuclear imaging) performed before discharge or within 72 hours as outpatient 1

Admission Criteria

Admit to hospital if any of the following develop during observation 1:

• Recurrent ischemic chest discomfort
• New ECG abnormalities on follow-up tracings
• Elevated cardiac biomarkers on repeat measurement
• Hemodynamic abnormalities (new or worsening heart failure)
• Positive stress test 1

Common Pitfalls to Avoid

• Do not rely on traditional CAD risk factors (age, smoking, hyperlipidemia) to determine admission versus discharge—symptoms, ECG, and troponin are far more important 1
• Do not discharge patients with normal initial troponin without waiting 6-12 hours from symptom onset, as troponin may not rise immediately 1
• Do not use total CK, AST, ALT, or LDH as primary tests for myocardial injury—cardiac-specific troponin is mandatory 1
• Do not assume nitroglycerin-responsive pain excludes ACS—many non-cardiac causes also respond to nitrates 4
• Avoid excessive nitroglycerin use as tolerance can develop with continuous high-dose administration 4
• Do not combine nitroglycerin with PDE-5 inhibitors (sildenafil, tadalafil, vardenafil) as severe hypotension may result 4