What is the management of ST-Elevation Myocardial Infarction (STEMI) in a patient without access to Percutaneous Coronary Intervention (PCI) and thrombolysis?

Management of STEMI Without Available PCI and Thrombolysis

When both PCI and thrombolysis are unavailable, focus on immediate supportive medical therapy, aggressive risk factor management, and urgent transfer arrangements to a facility capable of definitive reperfusion therapy. 1

Immediate Medical Therapy

Without reperfusion options, initiate the following medications immediately:

• Aspirin 162-325 mg (chewed for rapid absorption) to inhibit platelet aggregation 1, 2
• Clopidogrel 300 mg loading dose (or 600 mg if younger than 75 years) as dual antiplatelet therapy 2
• Oral beta-blockers (metoprolol 25-50 mg or equivalent) within the first 24 hours if no contraindications exist (heart failure, hypotension, bradycardia, or heart block) 1
• ACE inhibitors (or ARBs if ACE-intolerant) within 24 hours, particularly for anterior MI, heart failure, or ejection fraction <40% 1
• High-intensity statin therapy (atorvastatin 80 mg or rosuvastatin 40 mg) immediately 1
• Anticoagulation with unfractionated heparin (60 units/kg bolus, maximum 4000 units, followed by 12 units/kg/hour infusion, maximum 1000 units/hour) or low-molecular-weight heparin (enoxaparin 1 mg/kg subcutaneously every 12 hours) 2, 3

Urgent Transfer Protocol

Arrange immediate transfer to a PCI-capable facility regardless of time delay from MI onset, as this represents the only definitive treatment option. 1

Transfer priorities:

• Patients with cardiogenic shock or acute severe heart failure should be transferred immediately for cardiac catheterization and revascularization, irrespective of time delay from MI onset 1
• All other STEMI patients should be transferred as rapidly as possible, with a system goal of first medical contact-to-device time of 120 minutes or less 1
• Communicate clearly with the receiving facility about the patient's clinical status, time of symptom onset, ECG findings, and current hemodynamic stability 1
• Bypass the emergency department at the receiving facility and transfer directly to the catheterization laboratory when possible 2

Supportive Care During Stabilization

While awaiting transfer, provide:

• Supplemental oxygen only if oxygen saturation is <90% or respiratory distress is present (avoid routine oxygen in normoxic patients) 1
• Intravenous morphine 2-4 mg for pain relief if needed, with increments every 5-15 minutes (use cautiously as it may delay antiplatelet absorption) 1
• Continuous cardiac monitoring for arrhythmias, with defibrillator immediately available 1, 2
• Hemodynamic monitoring with frequent vital signs assessment 1

Special Circumstances Requiring Immediate Attention

Cardiogenic Shock:

• Transfer immediately even without reperfusion capability, as mortality approaches 50-80% without revascularization 1
• Consider intra-aortic balloon pump if available to improve coronary perfusion during transfer 4
• Avoid routine inotropes unless absolutely necessary for hemodynamic support 1

Ventricular Arrhythmias:

• Defibrillate ventricular fibrillation or pulseless ventricular tachycardia immediately 1
• Amiodarone 150 mg IV over 10 minutes for sustained ventricular tachycardia with pulse, followed by 1 mg/min infusion for 6 hours 1
• Avoid prophylactic lidocaine (increases mortality) 1

Complete Heart Block:

• Transcutaneous or transvenous pacing if symptomatic bradycardia or hemodynamic compromise 1
• Atropine 0.5-1 mg IV may be attempted first for inferior MI with bradycardia 1

Critical Time Windows and Prognosis

The mortality benefit of reperfusion therapy diminishes significantly after 12 hours from symptom onset, but patients with ongoing ischemia may still benefit up to 24 hours. 1

• Within 0-2 hours: Maximum myocardial salvage potential—transfer urgency is absolute 1
• 2-12 hours: Substantial benefit remains—aggressive transfer efforts justified 1
• 12-24 hours: Consider transfer if ongoing ischemia (persistent chest pain, ST-elevation, hemodynamic instability) 1
• Beyond 24 hours: Reperfusion therapy generally not indicated unless ongoing ischemia or cardiogenic shock 1

Common Pitfalls to Avoid

• Do not delay aspirin or other medical therapy while arranging transfer—these should be administered simultaneously 1, 2
• Do not wait for cardiac biomarkers to confirm diagnosis if ECG shows STEMI—treatment decisions are based on ECG and clinical presentation 1
• Do not administer NSAIDs (except aspirin) as they increase mortality and risk of myocardial rupture 1
• Do not give calcium channel blockers routinely in acute STEMI—they do not improve outcomes and may cause harm 1
• Do not delay transfer to perform echocardiography or other diagnostic tests unless they will change immediate management 1

Documentation and Communication

Ensure clear documentation of:

• Time of symptom onset (critical for reperfusion decisions at receiving facility) 1
• ECG findings with specific ST-segment elevation measurements 1
• Contraindications to fibrinolysis (in case receiving facility considers pharmaco-invasive strategy) 2
• Medications administered with exact times and doses 1
• Hemodynamic status and any complications during stabilization 1