What is the management of Acute Coronary Syndrome (ACS) with ST-Elevation Myocardial Infarction (STEMI)?

Management of ST-Elevation Myocardial Infarction (STEMI)

Primary percutaneous coronary intervention (PCI) performed within 120 minutes of STEMI diagnosis is the definitive reperfusion strategy and should be initiated immediately, with patients transferred directly to the catheterization laboratory bypassing the emergency department. 1

Initial Assessment and Diagnosis

• Obtain a 12-lead ECG within 10 minutes of first medical contact and initiate continuous ECG monitoring with defibrillator capacity immediately in all patients with suspected STEMI. 1, 2

• Do not administer routine oxygen therapy unless oxygen saturation is below 90%. 1, 2

• Assess for STEMI equivalents including new left bundle branch block, isolated ST depression in anterior leads with ST elevation in aVR (suggesting left main or multivessel disease), and hyperacute T-waves. 1

Reperfusion Strategy Selection

The critical decision point is whether primary PCI can be performed within 120 minutes of STEMI diagnosis:

Primary PCI Strategy (Preferred)

• If primary PCI can be performed within 120 minutes, proceed immediately to the catheterization laboratory with the patient bypassing the emergency department and CCU/ICCU. 1, 2

• PCI-capable centers must deliver 24/7 service and perform primary PCI without delay. 1, 2

• Use radial artery access as the standard approach and implant drug-eluting stents routinely. 1, 2

• Do not perform routine thrombus aspiration or deferred stenting—both are contraindicated. 1, 2

Fibrinolytic Strategy (When PCI Delayed)

• If the anticipated time from STEMI diagnosis to PCI exceeds 120 minutes, initiate fibrinolytic therapy immediately (within 10 minutes of STEMI diagnosis), preferably in the pre-hospital setting. 1, 2

• Use a fibrin-specific agent: tenecteplase, alteplase, or reteplase. 1, 2

• All patients receiving fibrinolysis must be transferred to a PCI-capable center immediately after fibrinolytic administration. 1, 2

Antithrombotic Therapy

For Primary PCI

• Administer aspirin 150-325 mg orally (chewable) or 250-500 mg IV if unable to swallow as soon as possible. 1, 2

• Add a potent P2Y12 inhibitor before or at the time of PCI: 1, 2

  • Prasugrel 60 mg loading dose, then 10 mg daily (preferred in most STEMI patients undergoing PCI) 3
  • Ticagrelor 180 mg loading dose, then 90 mg twice daily (alternative potent option) 1, 2
  • Clopidogrel 600 mg loading dose only if prasugrel and ticagrelor are unavailable or contraindicated 1, 2

• Administer unfractionated heparin as IV bolus at 100 U/kg (60 U/kg if GPIIb/IIIa inhibitors are used). 2

• Do not use fondaparinux for primary PCI—it is contraindicated. 1, 2

For Fibrinolytic Strategy

• Administer aspirin orally or IV. 1, 2

• Add clopidogrel 300 mg loading dose (not prasugrel or ticagrelor, which are not indicated for fibrinolytic strategy). 1, 2

• Anticoagulation with enoxaparin IV followed by subcutaneous (preferred over unfractionated heparin) or unfractionated heparin as weight-adjusted IV bolus followed by infusion, continued until revascularization or for hospital stay up to 8 days. 1, 2

Critical Prasugrel Considerations

Prasugrel is contraindicated in patients with:

• Prior transient ischemic attack (TIA) or stroke at any time 3
• Active pathological bleeding 3

Exercise caution with prasugrel in:

• Patients ≥75 years: generally not recommended due to increased fatal and intracranial bleeding risk, except in high-risk situations (diabetes or prior MI) where benefit may outweigh risk 3
• Patients <60 kg: reduce maintenance dose to 5 mg daily due to increased bleeding risk 3
• Patients likely to undergo urgent CABG: do not start prasugrel; if already on prasugrel, discontinue at least 7 days before surgery when possible 3

Post-Fibrinolysis Management

• Perform rescue PCI immediately if fibrinolysis fails (<50% ST-segment resolution at 60-90 minutes) or at any time with hemodynamic/electrical instability or worsening ischemia. 1, 2

• Perform angiography and PCI of the infarct-related artery between 2-24 hours after successful fibrinolysis. 1, 2

• Perform emergency angiography and PCI immediately in patients developing heart failure or cardiogenic shock. 1, 2

Special Populations

Cardiac Arrest with STEMI

• Proceed with primary PCI strategy in patients with resuscitated cardiac arrest and ST-elevation on post-resuscitation ECG. 1, 2

• 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 immediately after return of spontaneous circulation. 1

Cardiogenic Shock

• Perform emergency angiography and PCI immediately in patients with cardiogenic shock. 1, 2

• Consider PCI of non-infarct related arteries during the index procedure in cardiogenic shock. 1

In-Hospital Management

• Perform routine echocardiography during hospitalization to assess LV/RV function, detect mechanical complications, and exclude LV thrombus. 2

• Continue dual antiplatelet therapy (aspirin 75-100 mg daily plus prasugrel 10 mg daily or ticagrelor 90 mg twice daily) for 12 months unless excessive bleeding risk develops. 1, 2

• Initiate high-intensity statin therapy immediately with target LDL-C <70 mg/dL (1.8 mmol/L) or ≥50% reduction from baseline. 2

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

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

• Add a proton pump inhibitor in patients at high risk of gastrointestinal bleeding on dual antiplatelet therapy. 2

Post-Discharge Management

• Continue aspirin 75-100 mg daily indefinitely. 2

• Continue dual antiplatelet therapy for 12 months after PCI. 2

• Provide smoking cessation counseling with pharmacological support. 2

• Enroll patients in cardiac rehabilitation programs—this is strongly recommended. 2

Critical Pitfalls to Avoid

• Never delay primary PCI to obtain additional imaging or consultations—time is myocardium. The benefit of reperfusion is highly time-dependent, with greatest mortality benefit within the first 3 hours of symptom onset. 4

• Never withhold reperfusion therapy in asymptomatic patients beyond 48 hours—routine PCI of an occluded infarct-related artery >48 hours after STEMI onset is not indicated. 1

• Never discontinue dual antiplatelet therapy prematurely in the first few weeks after ACS—this dramatically increases the risk of subsequent cardiovascular events including stent thrombosis. 3

• Recognize atypical presentations, especially in women, elderly, and diabetic patients, which may lead to delayed diagnosis and treatment. 2

• Never use prasugrel in patients with prior TIA or stroke—use ticagrelor or clopidogrel instead. 3