STEMI Management
Primary percutaneous coronary intervention (PCI) is the definitive reperfusion strategy for STEMI and must be performed within 90 minutes of first medical contact, with patients transported directly to the catheterization laboratory bypassing the emergency department. 1
Immediate Diagnosis and Pre-Hospital Care
Obtain and interpret a 12-lead ECG within 10 minutes of first medical contact to diagnose STEMI (ST-elevation >0.1 mV in at least two contiguous leads, new left bundle branch block, or true posterior MI). 1
Emergency Medical Services (EMS) should diagnose STEMI in the field and activate the catheterization laboratory before hospital arrival, transporting patients directly to PCI-capable centers 24/7. 1, 2, 3
Initiate continuous ECG monitoring with defibrillator capacity immediately as coronary reperfusion may cause arrhythmias including sinus bradycardia, accelerated idioventricular rhythm, and ventricular tachycardia. 1
For inferior STEMI, obtain right-sided ECG leads (V3R-V4R) to screen for right ventricular infarction, which occurs in 30-50% of inferior STEMIs and dramatically alters hemodynamic management (avoid nitrates, diuretics, morphine; use aggressive IV fluid resuscitation). 4
Immediate Pharmacotherapy
Antiplatelet Therapy
Administer aspirin 150-325 mg oral (chewable) or IV immediately as soon as STEMI is diagnosed. 1, 4
Add a potent P2Y12 inhibitor before or at the time of PCI, with the following hierarchy: 1, 4
Anticoagulation
For primary PCI: Administer unfractionated heparin as weight-adjusted IV bolus followed by infusion. 1, 5
For fibrinolytic therapy: Administer enoxaparin IV followed by subcutaneous (preferred over unfractionated heparin). 1, 5
Reperfusion Strategy Selection
Primary PCI (Preferred Strategy)
Primary PCI is indicated for all STEMI patients presenting within 12 hours of symptom onset when it can be performed within 90-120 minutes of first medical contact. 1
Systems goal: First medical contact-to-balloon time ≤90 minutes for PCI-capable hospitals. 1
For interhospital transfer: Door-to-balloon time at the second hospital should be within 90 minutes from first hospital door. 1
Direct transport to PCI centers is preferred over transport to the nearest hospital if interhospital transfer will subsequently be required. 1
Primary stenting reduces subsequent target-vessel revascularization compared to balloon angioplasty alone, with no difference in mortality or reinfarction rates. 1
Fibrinolytic Therapy (When PCI Cannot Be Delivered Timely)
If primary PCI cannot be performed within 90-120 minutes of STEMI diagnosis, initiate fibrinolytic therapy within 30 minutes of hospital presentation using a fibrin-specific agent (tenecteplase, alteplase, or reteplase). 1, 5
The mortality benefit of PCI over fibrinolysis exists only when PCI is delayed by no more than 60 minutes compared to when fibrinolysis could be initiated. 1
Fibrinolysis is particularly important when symptom duration is <3 hours, as more ischemic myocardium can be salvaged. 1
Tenecteplase Dosing
Administer tenecteplase as a single weight-adjusted IV bolus: 5
- 30 mg for weight <60 kg
- 35 mg for 60-69 kg
- 40 mg for 70-79 kg
- 45 mg for 80-89 kg
- 50 mg for ≥90 kg
For patients ≥75 years old, reduce dose by 50% to reduce stroke risk. 5
Post-Fibrinolytic Management
Transfer to a PCI-capable center must be initiated immediately after fibrinolysis, without waiting to assess reperfusion success. 5, 6
Perform rescue PCI immediately if: 5, 6
- <50% ST-segment resolution at 60-90 minutes
- Persistent chest pain
- Hemodynamic or electrical instability
Perform routine angiography and PCI of the infarct-related artery 2-24 hours after successful fibrinolysis, which reduces mortality by 38% and reinfarction by 41%. 4, 5
Special Populations
For fibrinolytic-ineligible patients (contraindications to fibrinolysis): 1
- Primary PCI should be performed within 12 hours of symptom onset
- Consider PCI for patients presenting 12-24 hours after symptom onset if they have severe CHF, hemodynamic/electrical instability, or persistent ischemic symptoms
For patients with cardiogenic shock: 1, 5
- Transport immediately to a facility capable of cardiac catheterization and rapid revascularization
- Primary PCI is preferred over fibrinolytic therapy
For resuscitated cardiac arrest patients with ECG consistent with STEMI: 1
- Primary PCI is indicated
- Initiate targeted temperature management early (32-36°C for 24 hours)
- Do not use pre-hospital cooling with rapid infusion of large volumes of cold IV fluid
Adjunctive Medical Therapy
Beta-Blockers
Initiate early oral beta-blocker therapy within 24 hours in patients who are not at high risk for complications (avoid in patients with signs of heart failure, low output state, increased risk for cardiogenic shock, or other contraindications). 1
ACE Inhibitors/ARBs
Start ACE inhibitors early in stable high-risk patients (anterior MI, previous MI, Killip class ≥II, heart failure signs, LVEF <0.40) and continue indefinitely. 1
Use ARBs in patients intolerant of ACE inhibitors who have heart failure or LVEF <0.40. 1
Statins
Initiate high-intensity statin therapy immediately with target LDL-C <70 mg/dL (preferably within 24 hours of STEMI). 1, 4
Aldosterone Blockade
Add aldosterone blockade in patients without significant renal dysfunction or hyperkalemia who are already receiving therapeutic doses of an ACE inhibitor, have LVEF ≤0.40, and have either diabetes or heart failure. 1
Critical Contraindications and Pitfalls
Nitrate Contraindication
Avoid nitrates in patients who have taken phosphodiesterase-5 inhibitors (contraindicated for at least 48 hours after tadalafil), as the combination can cause severe, potentially fatal hypotension. 6
Avoid nitrates in right ventricular infarction (identified by ST elevation in V3R-V4R); use morphine for pain control instead. 4, 6
Bleeding Risk with Fibrinolysis
Tenecteplase increases bleeding risk, including intracranial hemorrhage. 7
Absolute contraindications to fibrinolysis include: 1, 5
- Prior intracranial hemorrhage
- Known structural cerebral vascular lesion
- Ischemic stroke within 3 months
- Suspected aortic dissection
- Active bleeding
- Significant closed-head trauma within 3 months
Avoid intramuscular injections and minimize arterial punctures during and after fibrinolytic therapy. 7
Facilitated PCI Strategy
Do not use full-dose fibrinolysis followed by immediate planned PCI (facilitated PCI), as this strategy may be harmful with trends toward worse outcomes including increased mortality, cardiogenic shock, CHF, recurrent MI, and repeat revascularization. 1, 7
In patients with large STEMI, choose either thrombolysis or PCI as the primary treatment strategy, not both simultaneously. 7
Post-Reperfusion Care
Continue dual antiplatelet therapy for 12 months unless excessive bleeding risk develops. 1, 4
Perform routine echocardiography during hospitalization to assess LV/RV function, detect mechanical complications, and exclude LV thrombus. 4, 6
Monitor patients for at least 24 hours after reperfusion therapy for arrhythmias and complications. 1
Discontinue NSAIDs (except aspirin) due to increased risks of mortality, reinfarction, hypertension, heart failure, and myocardial rupture. 1