What are the current guidelines for the treatment of ST-Elevation Myocardial Infarction (STEMI)?

Current Guidelines for STEMI Treatment

Patients with STEMI presenting within 12 hours of symptom onset should receive immediate reperfusion therapy—primary PCI is preferred if it can be performed within 120 minutes of first medical contact; otherwise, fibrinolytic therapy should be administered. 1

Immediate Pre-Hospital and Emergency Management

Recognition and Initial Response

• Patients should chew aspirin 162-325 mg immediately upon symptom recognition unless absolutely contraindicated 1
• Emergency medical services should obtain 12-lead ECG within 10 minutes of first medical contact 1
• ECG monitoring with defibrillator capacity must be initiated immediately 1
• One sublingual nitroglycerin dose may be taken at symptom onset; if no improvement within 5 minutes, activate emergency services 1

Pre-Hospital Triage

• Regional STEMI networks should direct patients to primary PCI-capable centers operating 24/7 1
• Patients should bypass the emergency department and proceed directly to the catheterization laboratory 1
• Pre-hospital fibrinolysis is reasonable if EMS personnel are appropriately trained and PCI cannot be achieved within recommended timeframes 1

Reperfusion Strategy Selection

Primary PCI (Preferred Method)

• Primary PCI is indicated for all STEMI patients presenting within 12 hours of symptom onset if it can be performed within 120 minutes of first medical contact 1
• PCI is also recommended for patients with resuscitated cardiac arrest and ECG showing STEMI 1
• In asymptomatic patients, routine PCI of an occluded infarct-related artery >48 hours after STEMI onset is NOT indicated 1

Fibrinolytic Therapy (When PCI Unavailable)

• Administer fibrinolysis within 12 hours of symptom onset if primary PCI cannot be performed within 120 minutes 1
• Fibrin-specific agents (tenecteplase, alteplase, reteplase) are preferred over streptokinase due to non-antigenic properties 2
• Streptokinase is absolutely contraindicated within 6 months of previous exposure due to high risk of anaphylaxis 2
• If allergic reaction occurs during streptokinase infusion, slow the rate for isolated urticaria; if severe, stop and arrange rescue PCI 2

Acute Pharmacological Management

Antiplatelet Therapy

Dual Antiplatelet Therapy (DAPT) is mandatory:

• Aspirin: 162-325 mg loading dose (chewed), then 75-162 mg daily indefinitely 1
• P2Y12 Inhibitor: Add immediately to aspirin 1

For patients undergoing primary PCI:

• Prasugrel 60 mg loading dose, then 10 mg daily is preferred (reduces CV death, MI, and stroke compared to clopidogrel) 3
• Alternative: Ticagrelor (loading and maintenance per protocol) 1
• Clopidogrel 75 mg daily is acceptable but less effective 1

For patients receiving fibrinolysis:

• Clopidogrel 75 mg daily (loading dose may be considered) 1

Duration of DAPT:

• No stent: minimum 14 days 1
• Bare-metal stent: minimum 1 month, ideally 12 months unless high bleeding risk 1
• Drug-eluting stent: 12 months minimum (3 months for sirolimus, 6 months for paclitaxel) 1

Anticoagulation

• Unfractionated heparin is standard for primary PCI (enoxaparin or bivalirudin are alternatives) 1
• For fibrinolysis: enoxaparin preferred (unfractionated heparin is alternative) 1

Beta-Blockers

• Intravenous beta-blockers should NOT be given routinely in acute STEMI (Class III recommendation) 1
• Oral beta-blocker therapy should be initiated within 24 hours in patients without contraindications (heart failure, hypotension, bradycardia, heart block) 1
• Continue indefinitely 1

Contraindications to avoid:

• NSAIDs (except aspirin) must be discontinued immediately due to increased mortality, reinfarction, heart failure, and myocardial rupture risk 1
• Ibuprofen specifically blocks aspirin's antiplatelet effects 1

Post-Reperfusion Management (First 24-48 Hours)

Monitoring

• Continuous cardiac monitoring for minimum 24 hours 1
• Assess for complications: arrhythmias, heart failure, mechanical complications 1

ACE Inhibitor Initiation

Start ACE inhibitors early in high-risk patients:

• Anterior MI (LAD territory infarction) 4
• Previous MI 4
• Killip class ≥II 4
• LVEF <40% 1, 4
• Clinical or radiographic heart failure 1, 4

Dosing protocol for lisinopril:

• Confirm systolic BP ≥100 mmHg 4
• Check creatinine ≤2.5 mg/dL (men) or ≤2.0 mg/dL (women) 4
• Verify potassium ≤5.0 mEq/L 4
• Start lisinopril 5 mg orally within 24 hours 4
• Target dose: 10 mg daily 4
• Continue indefinitely (minimum 6 weeks) 4
• Hold if systolic BP drops below 100 mmHg or >30 mmHg below baseline 4

For ACE inhibitor intolerance:

• Switch to ARB (valsartan 20 mg initially, target 160 mg twice daily, or candesartan) if LVEF <40% or heart failure present 1, 4

Aldosterone Blockade

• Add to ACE inhibitor and beta-blocker in patients with LVEF ≤40% and diabetes or heart failure 1
• Contraindicated if creatinine >2.5 mg/dL (men) or >2.0 mg/dL (women), or potassium >5.0 mEq/L 1

Secondary Prevention and Long-Term Management

Lipid Management

• LDL-C goal: <70 mg/dL 1
• Start high-intensity statin therapy immediately 1
• If triglycerides ≥200 mg/dL after LDL goal achieved, consider adding fibrate or niacin 1

Lifestyle Modifications

• Smoking cessation: Mandatory counseling plus pharmacotherapy (nicotine replacement, bupropion) 1
• Exercise: Minimum 30 minutes daily or at least 3-4 times weekly 1
• Cardiac rehabilitation strongly recommended, especially for high-risk patients 1
• Weight management: Target BMI 18.5-24.9 kg/m²; waist <35 inches (women) or <40 inches (men) 1

Diabetes Management

• Target HbA1c <7% 1
• Aggressive modification of all cardiovascular risk factors 1

Anticoagulation (When Indicated)

• Atrial fibrillation: Warfarin (INR 2.0-3.0) 1
• LV thrombus: Warfarin for minimum 3 months, indefinitely if low bleeding risk 1
• When combining warfarin with DAPT: target INR 2.0-2.5 with low-dose aspirin (75-81 mg) and clopidogrel 75 mg 1

Additional Therapies

• Influenza vaccination annually 1
• Screen for depression, anxiety, and sleep disorders 1
• Consider cognitive-behavioral therapy and SSRIs for post-MI depression 1

Critical Pitfalls to Avoid

• Do not delay reperfusion therapy for any reason—time is myocardium 1
• Do not give IV beta-blockers acutely (increases mortality in certain subsets) 1
• Do not continue NSAIDs (except aspirin) 1
• Do not use streptokinase if given within previous 6 months 2
• Do not perform routine PCI of occluded artery >48 hours after symptom onset in asymptomatic patients 1
• Do not use antioxidant vitamin supplements (no proven benefit) 1