What is the management approach for a patient with ST-Elevation Myocardial Infarction (STEMI)?

Management of ST-Elevation Myocardial Infarction (STEMI)

The cornerstone of STEMI management is immediate reperfusion therapy, with primary percutaneous coronary intervention (PCI) being the preferred strategy when it can be performed within 90 minutes of first medical contact or 120 minutes for patients requiring transfer to a PCI-capable facility. 1, 2, 3

Initial Assessment and Management

• Immediately administer 162-325 mg of non-enteric coated aspirin to all STEMI patients upon first medical contact 1, 2, 3
• Perform a 12-lead ECG and have it interpreted by an experienced physician within 10 minutes of emergency department arrival 1
• Administer supplemental oxygen only to patients with arterial oxygen saturation <90% or respiratory distress 1, 2
• Provide morphine sulfate for patients with ongoing ischemic pain or pulmonary congestion 1, 2
• Initiate oral beta-blocker therapy promptly in patients without contraindications (heart failure, hypotension, bradycardia) 4, 1, 2
• Consider intravenous beta-blockers for patients with tachyarrhythmias or hypertension without contraindications 4, 3
• Administer intravenous nitroglycerin for persistent ischemia, heart failure, or hypertension in the first 48 hours 2

Reperfusion Strategy Decision-Making

• Primary PCI is the preferred reperfusion strategy when it can be performed within 90 minutes of first medical contact (door-to-balloon time) 1, 2, 3
• For patients presenting to non-PCI capable facilities, transfer for primary PCI if first medical contact-to-device time can be achieved within 120 minutes 1, 2
• If primary PCI cannot be performed within 120 minutes, administer fibrinolytic therapy within 30 minutes of hospital arrival 1, 2
• For high-risk patients presenting within 2 hours of symptom onset, the PCI-related delay should not exceed 90 minutes 1

Primary PCI Strategy

• Administer dual antiplatelet therapy before PCI, including aspirin and a P2Y12 inhibitor (prasugrel, ticagrelor, or clopidogrel) as early as possible 1, 3
• For patients receiving stents, dual antiplatelet therapy should be continued for at least 12 months 1, 2, 5
• Clopidogrel should be administered with a 300 mg loading dose followed by 75 mg daily maintenance dose 5
• Consider the patient's CYP2C19 metabolizer status when prescribing clopidogrel, as poor metabolizers may have reduced antiplatelet effect 5

Management of Complications

• For cardiogenic shock, emergency revascularization is recommended regardless of time delay from MI onset 1, 2, 3
• Intra-aortic balloon counterpulsation is useful for patients with cardiogenic shock not quickly stabilized with pharmacological therapy 1, 2, 3
• For patients ≥75 years with cardiogenic shock, emergency revascularization should still be considered, especially in those with good prior functional status 1, 2, 3
• Ventricular septal rupture, free wall rupture, and papillary muscle rupture require urgent surgical consultation 1, 2

Post-STEMI Care

• Continue aspirin 75-162 mg daily indefinitely 4, 2
• Initiate ACE inhibitors within 24 hours in patients with anterior STEMI, heart failure, or ejection fraction ≤0.40 4, 1, 2
• Consider angiotensin receptor blockers (ARBs) in patients intolerant of ACE inhibitors 2
• Start high-intensity statin therapy in all STEMI patients without contraindications 1, 3
• Continue beta-blockers in all eligible patients indefinitely 4, 2
• Manage blood pressure to a target level of less than 140/90 mm Hg and to less than 130/80 mm Hg for patients with diabetes or chronic kidney disease 4
• Initiate hypoglycemic therapy in diabetic patients to achieve HbA1c less than 7% 4

Special Considerations

• Avoid immediate-release nifedipine in STEMI patients due to reflex sympathetic activation, tachycardia, and hypotension 4, 2
• Do not administer beta-blockers or calcium channel blockers to patients with frank cardiac failure, pulmonary congestion, or signs of low-output state 1, 3
• For patients requiring anticoagulation (atrial fibrillation, LV thrombus), warfarin should be prescribed with an INR target of 2.0-3.0 4
• In patients requiring triple therapy (aspirin, P2Y12 inhibitor, and warfarin), an INR of 2.0-2.5 is recommended with low-dose aspirin (75-81 mg) and clopidogrel 75 mg 4

Common Pitfalls to Avoid

• Do not delay reperfusion therapy to wait for cardiac biomarker results; initiate treatment based on clinical presentation and ECG findings 1
• Avoid diltiazem and verapamil in patients with STEMI and associated systolic LV dysfunction and CHF 4
• Do not rely on serial biomarker measurements to diagnose reinfarction within the first 18 hours after STEMI onset 1
• Avoid discontinuing clopidogrel prematurely in patients with stents due to increased risk of stent thrombosis 5