What is the current concept of ST‑segment–elevation myocardial infarction (STEMI) management?

Current Concept of STEMI Management

The cornerstone of modern STEMI management is immediate reperfusion via primary PCI performed within 120 minutes of diagnosis, supported by dual antiplatelet therapy (aspirin plus prasugrel or ticagrelor) and anticoagulation, with fibrinolysis reserved only when timely PCI is not achievable. 1

Initial Diagnosis and Time-Critical Actions

Obtain a 12-lead ECG within 10 minutes of first medical contact and initiate continuous ECG monitoring with defibrillator capacity immediately. 1, 2, 3 The moment of STEMI diagnosis (when the ECG shows ST-elevation or equivalent) becomes "time zero" for all subsequent time-dependent decisions. 1

ECG Patterns Beyond Classic ST-Elevation

Recognize that coronary occlusion can present without typical ST-elevation, including: 1, 2

• New left bundle branch block
• Ventricular pacing
• Hyperacute T-waves
• Isolated ST-depression in anterior leads with ST-elevation in aVR (suggesting left main or multivessel disease)
• Universal ST-depression with ST-elevation in aVR

In these atypical ECG presentations with ongoing ischemic symptoms, pursue an urgent primary PCI strategy immediately. 1, 2

Critical Initial Medications

• Aspirin 150-325 mg orally (or 250-500 mg IV if unable to swallow) should be administered immediately at first medical contact. 1, 2, 3
• Avoid routine oxygen therapy unless oxygen saturation is <90%. 1, 2, 3
• Morphine sulfate may be given for pain control and anxiety reduction. 3

Reperfusion Strategy Selection: The 120-Minute Rule

Primary PCI is the preferred reperfusion method when it can be performed within 120 minutes from STEMI diagnosis. 1, 2, 3 If the anticipated time from diagnosis to PCI-mediated reperfusion exceeds 120 minutes, initiate fibrinolysis immediately (within 10 minutes of STEMI diagnosis). 1

Primary PCI Strategy

Transfer patients directly to the catheterization laboratory, bypassing the emergency department and ICU. 1, 2, 3 PCI-capable centers must deliver 24/7 service without delay. 1

Technical Standards During Primary PCI

• Routine radial access is the standard of care to minimize bleeding complications. 1, 2
• Drug-eluting stents (DES) are the standard implant. 1, 2
• Routine thrombus aspiration is contraindicated. 1, 2
• Deferred stenting is contraindicated. 1

Antithrombotic Therapy for Primary PCI

Administer a potent P2Y12 inhibitor before or at the time of PCI: 1, 2, 3

• Prasugrel 60 mg loading dose, OR
• Ticagrelor 180 mg loading dose
• Clopidogrel only if prasugrel/ticagrelor unavailable

Anticoagulation during PCI: 1, 2

• Unfractionated heparin (UFH) 100 U/kg IV bolus (60 U/kg if GPIIb/IIIa inhibitors used)
• Enoxaparin or bivalirudin are alternatives
• Fondaparinux is contraindicated for primary PCI 2, 3

Fibrinolytic Strategy (When PCI Cannot Be Achieved Within 120 Minutes)

Initiate fibrinolysis as soon as possible, preferably in the pre-hospital setting. 2 Use a fibrin-specific agent: 2

• Tenecteplase (single weight-adjusted bolus 0.53 mg/kg, maximum 50 mg)
• Alteplase
• Reteplase

For patients ≥75 years, reduce tenecteplase dose by 50% to minimize stroke risk. 2

Adjunctive Therapy with Fibrinolysis

• Aspirin (oral or IV) 1, 2
• Clopidogrel (not prasugrel/ticagrelor with fibrinolysis) 1, 2
• Enoxaparin (preferred) or unfractionated heparin 1, 2
• Continue anticoagulation until revascularization or for hospital duration (up to 8 days) 2

Monitor for successful reperfusion at 60-90 minutes: assess symptom relief, hemodynamic stability, and ≥50% reduction in ST-segment elevation. 2

Management of Non-Infarct Related Artery (Non-IRA) Lesions

Evaluate severe stenosis in non-IRA vessels (by angiography or FFR) and consider treatment before hospital discharge, either immediately during index PCI or staged later. 1 In cardiogenic shock, perform non-IRA PCI during the index procedure. 1

Special Clinical Scenarios

Cardiac Arrest with STEMI

Patients with resuscitated cardiac arrest and ST-elevation on post-resuscitation ECG should undergo primary PCI immediately. 1 For those without ST-elevation but high suspicion of ongoing ischemia, perform urgent angiography within 2 hours. 1 Initiate targeted temperature management early after resuscitation in patients who remain unresponsive. 1 Do not use pre-hospital cooling with rapid infusion of large volumes of cold IV fluid. 1

Cardiogenic Shock

Perform emergency angiography and PCI immediately regardless of time from symptom onset. 2, 3 Consider intra-aortic balloon pump or alternative left ventricular assist devices for hemodynamic stabilization. 2, 3

Late Presentation (>12 Hours from Symptom Onset)

Routine PCI of an occluded infarct-related artery >48 hours after STEMI onset is not indicated in asymptomatic patients. 1 However, in patients with hemodynamic instability, electrical instability, or ongoing symptoms, pursue primary PCI regardless of time delay. 1

In-Hospital Management and Monitoring

Monitor patients for at least 24 hours after reperfusion therapy. 1 Perform routine echocardiography during hospitalization to assess LV and RV function, detect mechanical complications, and exclude LV thrombus. 2

Pharmacotherapy During Hospitalization

Dual antiplatelet therapy (DAPT): 1, 2, 3

• Aspirin 75-100 mg daily PLUS
• Prasugrel 10 mg daily OR ticagrelor 90 mg twice daily
• Continue for 12 months

High-intensity statin therapy should be initiated immediately with target LDL-C <70 mg/dL (1.8 mmol/L) or ≥50% reduction. 2, 3

Beta-blockers should be started orally in patients with heart failure and/or LVEF <40% unless contraindicated. 1, 2, 3

ACE inhibitors should be initiated within 24 hours in patients with heart failure, LV systolic dysfunction, diabetes, or anterior infarct. 1, 2, 3

Special Populations Requiring Dose Adjustments

Patients on oral anticoagulants, those with renal insufficiency, and the elderly require careful attention to dose adjustments of antithrombotic therapies. 1 Patients with diabetes and those not undergoing reperfusion need additional monitoring. 1

Post-Discharge and Long-Term Management

Continue aspirin 75-100 mg indefinitely. 2, 3 Maintain DAPT for 12 months after PCI unless contraindications arise. 2, 3 Use a proton pump inhibitor (PPI) with DAPT in patients at high risk of gastrointestinal bleeding. 2

Enroll all patients in cardiac rehabilitation programs. 2, 3 Provide smoking cessation counseling with pharmacological support. 2, 3

MINOCA (Myocardial Infarction with Non-Obstructive Coronary Arteries)

A substantial proportion of STEMI patients do not have significant coronary stenosis on urgent angiography. 1 Perform additional diagnostic tests to identify the etiology and tailor appropriate therapy, which may differ from typical STEMI management. 1

Critical Pitfalls to Avoid

• Never delay primary PCI to obtain additional imaging or consultations—time is myocardium. 3
• Do not administer nitrates to patients who have taken phosphodiesterase-5 inhibitors within 24-48 hours due to severe hypotension risk. 3
• Do not withhold reperfusion therapy based on age alone—elderly patients derive similar relative benefit. 3
• Avoid routine thrombus aspiration and deferred stenting—both are contraindicated. 1, 2
• Women must receive equal treatment as men—they derive equal benefit from reperfusion and evidence-based therapies despite historical undertreatment. 1
• Atypical presentations (especially in women, elderly, and diabetic patients) may lead to delayed diagnosis—maintain high clinical suspicion. 2

Quality Improvement and Systems of Care

Pre-hospital management should be based on regional networks designed to deliver reperfusion therapy expeditiously, with coordination between EMS and hospitals using common written protocols. 1 EMS should alert the PCI center immediately after selecting the reperfusion strategy. 1 Use well-defined and validated quality indicators to measure and improve STEMI care. 1