What are the guidelines for managing ST-Elevation Myocardial Infarction (STEMI)?

Management of ST-Elevation Myocardial Infarction (STEMI)

Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy for STEMI patients when it can be performed within 90 minutes of first medical contact, with fibrinolytic therapy recommended if PCI cannot be achieved within 120 minutes. 1

Initial Assessment and Management

• Immediately administer 162-325 mg of non-enteric coated aspirin to all STEMI patients upon first medical contact 1
• Administer supplemental oxygen to maintain arterial saturation >90% only in patients with pulmonary congestion or hypoxemia 1
• Provide morphine sulfate for patients with ongoing ischemic pain or pulmonary congestion 1
• Administer oral beta-blockers promptly to patients without contraindications (such as heart failure, hypotension, or bradycardia) 1, 2
• Intravenous beta-blockers may be reasonable for patients with tachyarrhythmias or hypertension without contraindications 1
• Initiate intravenous nitroglycerin in the first 48 hours for persistent ischemia, heart failure, or hypertension 2

Reperfusion Strategies

• Primary PCI should be performed within 90 minutes of first medical contact (door-to-balloon time) 1
• For patients presenting to non-PCI capable facilities, transfer for primary PCI if first medical contact-to-device time can be achieved within 120 minutes 1
• If primary PCI cannot be performed within 120 minutes, administer fibrinolytic therapy (such as tenecteplase) within 30 minutes of hospital arrival 1, 3
• Administer antiplatelet therapy before PCI, including aspirin and a P2Y12 inhibitor (prasugrel, ticagrelor, or clopidogrel) as early as possible 1, 4
• Caution is advised with prasugrel in patients ≥75 years, <60 kg, or with history of stroke/TIA due to increased bleeding risk 4

Management of Complications

Cardiogenic Shock

• Emergency revascularization (PCI or CABG) is recommended regardless of time delay from MI onset for patients with cardiogenic shock 1, 2
• Intra-aortic balloon counterpulsation (IABP) is recommended for patients with cardiogenic shock not quickly reversed with pharmacological therapy 2, 5
• IABP is also indicated for STEMI patients with low-output state or recurrent ischemic chest discomfort with hemodynamic instability 2

Mechanical Complications

• Ventricular septal rupture, free wall rupture, and papillary muscle rupture require urgent surgical consultation 2
• CABG should be performed at the same time as repair of ventricular septal or free wall rupture 2

Arrhythmias

• Ventricular fibrillation or pulseless VT should be treated with unsynchronized electric shock 2
• Refractory polymorphic VT should be managed with aggressive reduction of myocardial ischemia, beta-blockers, and IABP 2

Post-STEMI Care

Pharmacotherapy

• Continue aspirin 75-162 mg daily indefinitely 2
• Maintain dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor for at least 12 months in patients receiving stents 1
• Initiate ACE inhibitors within 24 hours in all patients, particularly those with anterior MI, previous MI, heart failure, or LVEF <0.40 2, 1
• Consider angiotensin receptor blockers (ARBs) in patients intolerant of ACE inhibitors 2
• Start beta-blockers in all eligible patients and continue indefinitely 2
• Initiate high-intensity statin therapy in all patients without contraindications 1
• Consider aldosterone blockade in patients with LVEF ≤0.40 and either diabetes or heart failure, without significant renal dysfunction or hyperkalemia 2

Risk Factor Modification

• Target LDL-C should be substantially less than 100 mg/dL using statins as first-line therapy 2
• Maintain blood pressure <140/90 mmHg or <130/80 mmHg for patients with diabetes or chronic kidney disease 2
• Implement diabetes management with a goal HbA1c <7% 2
• Encourage smoking cessation with counseling and pharmacotherapy 2
• Recommend physical activity of at least 30 minutes, 3-4 days per week 2
• Target BMI of 18.5-24.9 kg/m² and appropriate waist circumference (<35 inches for women, <40 inches for men) 2

Special Considerations

• For patients ≥75 years with cardiogenic shock, emergency revascularization can be effective, especially with good prior functional status 1
• Avoid nifedipine (immediate-release form) in STEMI patients due to reflex sympathetic activation, tachycardia, and hypotension 2
• Beta-blockers or calcium channel blockers should not be administered to patients with frank cardiac failure, pulmonary congestion, or signs of low-output state 1
• Monitor for bleeding complications with fibrinolytic therapy and antiplatelet agents, especially in elderly patients, those with low body weight, or renal dysfunction 3, 4

Complications to Monitor

• Bleeding risk is increased with fibrinolytic therapy and antiplatelet agents, particularly intracranial hemorrhage 3, 4
• Reperfusion arrhythmias may occur and should be managed with standard anti-arrhythmic measures 3
• Deep vein thrombosis or pulmonary embolism should be treated with full-dose low molecular weight heparin and warfarin 2
• Recurrent ischemia requires escalation of medical therapy and urgent cardiac catheterization 2