What is the treatment for ST-Elevation Myocardial Infarction (STEMI)?

Treatment of ST-Elevation Myocardial Infarction (STEMI)

Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy and must be performed within 90 minutes at PCI-capable hospitals or within 120 minutes from first medical contact for patients requiring transfer. 1, 2

Immediate Actions at First Medical Contact

• Obtain a 12-lead ECG within 10 minutes of first medical contact and initiate continuous ECG monitoring with defibrillator capacity 1, 2
• Administer aspirin 150-325 mg orally (chewable preferred) or IV 250-500 mg if unable to swallow immediately 1, 2
• Avoid routine oxygen therapy unless oxygen saturation is <90% 1, 2
• Administer morphine sulfate 4-8 mg IV with increments of 2 mg at 5-15 minute intervals for pain control, anxiety reduction, and decreased sympathetic drive 1

Transfer patients directly to the catheterization laboratory, bypassing the emergency department entirely. 1, 2

Reperfusion Strategy Selection

Primary PCI (Preferred Method)

• Primary PCI is superior to fibrinolysis when performed by an experienced team within the specified time windows 1, 2, 3
• Administer a potent P2Y12 inhibitor before or at the time of PCI: ticagrelor 180 mg loading dose (preferred in most patients) or prasugrel 60 mg loading dose 1, 2
• For prasugrel specifically: do NOT use in patients with prior TIA or stroke (contraindicated), age ≥75 years (generally not recommended except in high-risk diabetes or prior MI), body weight <60 kg (consider 5 mg maintenance dose instead of 10 mg), or patients likely to undergo urgent CABG 4
• Anticoagulation during PCI should use unfractionated heparin IV bolus at 100 U/kg (60 U/kg if GPIIb/IIIa inhibitors are used) 2
• Fondaparinux is contraindicated for primary PCI 1, 2
• Drug-eluting stents are the standard of care over bare-metal stents 2
• Radial access is preferred over femoral access when feasible 2

Fibrinolytic Therapy (When PCI Cannot Be Achieved Within Time Windows)

• Initiate fibrinolysis immediately, preferably in the pre-hospital setting, if anticipated time from STEMI diagnosis to PCI exceeds 120 minutes 2
• Use a fibrin-specific agent: tenecteplase (preferred for single bolus administration), alteplase, or reteplase 2
• For tenecteplase: administer single weight-adjusted IV bolus of 30-50 mg (0.53 mg/kg); reduce dose by 50% in patients ≥75 years old to reduce stroke risk 2
• Administer aspirin and clopidogrel 300 mg loading dose with fibrinolysis 2
• Continue anticoagulation with unfractionated heparin or enoxaparin for at least 48 hours and preferably for the duration of hospitalization (up to 8 days) 2
• Monitor for successful reperfusion at 60-90 minutes post-administration: assess symptom relief, hemodynamic stability, and ≥50% reduction in ST-segment elevation 2

Special Populations and High-Risk Scenarios

Cardiogenic Shock

• Perform emergency angiography and PCI immediately regardless of time from symptom onset 5, 1, 2
• Insert intra-aortic balloon pump for hemodynamic stabilization 5, 1
• Consider alternative left ventricular assist devices for refractory cardiogenic shock 5
• In the absence of contraindications, administer fibrinolytic therapy if patient is unsuitable for either PCI or CABG 5

Cardiac Arrest with Post-Resuscitation ST-Elevation

• Pursue primary PCI strategy immediately 2

Patients Presenting 12 Hours to 14 Days After Symptom Onset

• Randomize to treatment only after coronary angiography is performed 4

In-Hospital Pharmacotherapy

Antiplatelet Therapy

• Dual antiplatelet therapy (DAPT) with aspirin 75-100 mg daily plus ticagrelor 90 mg twice daily (preferred) or prasugrel 10 mg daily for 12 months 1, 2
• Continue aspirin indefinitely after the 12-month DAPT period 1, 2
• For patients with body weight <60 kg on prasugrel, consider reducing maintenance dose to 5 mg daily due to increased bleeding risk 4

Lipid Management

• Initiate high-intensity statin therapy immediately with target LDL-C <70 mg/dL (1.8 mmol/L) or ≥50% reduction from baseline 1, 2
• Obtain fasting lipid profile within 24 hours of presentation 5

Beta-Blockers

• Start oral beta-blockers in patients with heart failure and/or LVEF <40% unless contraindicated 1, 2

ACE Inhibitors/ARBs

• Start ACE inhibitors within 24 hours in patients with heart failure, LV systolic dysfunction, diabetes, or anterior infarct 2

Anticoagulation for Specific Indications

• Provide anticoagulant therapy with vitamin K antagonist for patients with atrial fibrillation (CHADS2 score ≥2), mechanical heart valves, venous thromboembolism, or hypercoagulable disorder 5
• Minimize duration of triple-antithrombotic therapy (vitamin K antagonist + aspirin + P2Y12 inhibitor) to limit bleeding risk; consider 14 days for fibrinolysis patients, then transition to vitamin K antagonist plus single antiplatelet agent 5
• Target INR 2.0-2.5 (lower than usual) when combining vitamin K antagonist with DAPT 5
• Consider anticoagulation for patients with anteroapical akinesis or dyskinesis 5

Gastrointestinal Protection

• Use a proton pump inhibitor in combination with DAPT in patients at high risk of gastrointestinal bleeding 2

Critical Pitfalls to Avoid

• Never delay primary PCI to obtain additional imaging, consultations, or neurosurgical evaluation of incidental findings—time is myocardium and STEMI is the immediate life-threatening emergency 1, 6
• Do not administer nitrates to patients who have taken phosphodiesterase-5 inhibitors (sildenafil, tadalafil, vardenafil) within 24-48 hours due to risk of severe hypotension 1
• Do not withhold reperfusion therapy based on age alone—elderly patients derive similar relative benefit 1
• Glucocorticoids and nonsteroidal anti-inflammatory drugs are potentially harmful for treatment of pericarditis after STEMI 5
• Routine thrombus aspiration and deferred stenting are contraindicated 2
• Do not use prasugrel in patients with prior TIA or stroke (absolute contraindication) 4
• Discontinue prasugrel at least 7 days prior to any surgery when possible 4
• Recognize that morphine coadministration with prasugrel can decrease the Cmax of prasugrel's active metabolite by 31% and delay onset of platelet inhibition up to 2 hours in some patients 4

Post-Discharge Management

• Continue aspirin 75-100 mg daily indefinitely 1, 2
• Continue P2Y12 inhibitor for 12 months unless excessive bleeding risk develops 1, 2
• Enroll all patients in cardiac rehabilitation programs 1, 2
• Provide smoking cessation counseling with pharmacological support 1, 2
• Perform routine echocardiography during hospitalization to assess LV/RV function, detect mechanical complications, and exclude LV thrombus 2

Arrhythmia Management

• Implantable cardioverter-defibrillator therapy is indicated before discharge in patients who develop sustained ventricular tachycardia/ventricular fibrillation more than 48 hours after STEMI, provided the arrhythmia is not due to transient or reversible ischemia, reinfarction, or metabolic abnormalities 5

Pre-Discharge Risk Stratification

• Perform noninvasive testing for ischemia before discharge in patients who have not had coronary angiography and do not have high-risk clinical features warranting angiography 5