Latest Protocol for Myocardial Infarction (2025)

Classification of MI (Universal Definition)

STEMI Management Protocol

1. Immediate Actions (First 10 Minutes)

• 12-lead ECG within 10 minutes of arrival
• Aspirin 162–325 mg chewed immediately (buccal absorption for rapid COX-1 inhibition)
• Supplemental O₂ only if SpO₂ < 90% — routine O₂ is not recommended in normoxic patients
• IV access, continuous ECG monitoring, vitals

2. Reperfusion Strategy — The Core Decision

"In a large meta-analysis of 23 RCTs, pPCI was better than thrombolytic therapy at reducing death, reinfarction, and stroke in STEMI patients." — Fuster and Hurst's The Heart, 15th Ed.

3. Antiplatelet Therapy (Dual Antiplatelet — DAPT)

• Aspirin 75–100 mg daily (lifelong)
• P2Y12 inhibitor (add to aspirin):
  • Ticagrelor 180 mg load → 90 mg BID (preferred for ACS/PCI — stronger, reversible)
  • Prasugrel 60 mg load → 10 mg daily (preferred over clopidogrel post-PCI; avoid if prior stroke/TIA, age ≥75, weight <60 kg)
  • Clopidogrel 300–600 mg load → 75 mg daily (when ticagrelor/prasugrel not available or contraindicated)
• Duration: 12 months post-ACS as standard; may extend >12 months in high ischemic risk (diabetes, recurrent MI, CKD, complex CAD); may shorten to 1–6 months in high bleeding risk

4. Anticoagulation

• Unfractionated heparin (UFH) IV: most used peri-PCI (60–70 U/kg bolus, max 5000 U; target ACT 250–350 s)
• Bivalirudin (direct thrombin inhibitor): alternative to UFH, especially in HIT or high bleeding risk
• Enoxaparin (LMWH): 0.5 mg/kg IV for PCI, or 1 mg/kg SC BID for NSTEMI management
• Fondaparinux: preferred for NSTEMI medical management (not used with PCI)

5. Adjunctive Medical Therapy

NSTEMI / Unstable Angina Protocol

Risk Stratification First

• Very high risk (refractory ischemia, hemodynamic instability, VT/VF): Immediate PCI (<2 h)
• High risk (GRACE >140, troponin rise, dynamic ST changes): Early invasive (<24 h)
• Intermediate risk: Invasive within 24–72 h
• Low risk: Medical management; consider stress testing or CT coronary angiography

Key 2025 Updates vs Prior Guidelines

1. No routine oxygen in normoxic patients (was previously routine)
2. Colchicine (0.5 mg BID) — new recommendation for reducing pericarditis and potentially recurrent events post-MI
3. Inclisiran and PCSK9 inhibitors (evolocumab, alirocumab) — Class I for post-ACS patients not at LDL target on maximal statin therapy
4. Intravascular imaging (IVUS or OCT) during PCI — upgraded to Class I for complex lesions, guides stent sizing and deployment
5. Complete revascularization at index hospitalization vs. staged approach — now supported as equivalent (not mandatory immediate); individualized
6. Ticagrelor monotherapy after 1–3 months (dropping aspirin) — reasonable strategy in select high-bleeding-risk patients post-PCI
7. Outpatient GLP-1 RA initiation post-MI with obesity/T2DM — incorporated into discharge planning

Complications Management

Post-MI Secondary Prevention (Discharge)

1. DAPT for 12 months (aspirin + ticagrelor or prasugrel)
2. High-intensity statin — LDL target <55 mg/dL (1.4 mmol/L); add ezetimibe or PCSK9 inhibitor if needed
3. Beta-blocker — if LVEF ≤40% or HF
4. ACEi/ARB — if LVEF ≤40%, HF, DM, or HTN
5. Mineralocorticoid antagonist — if LVEF ≤40% + HF/DM
6. Cardiac rehabilitation — strongly recommended (reduces mortality ~25%)
7. Lifestyle modification — smoking cessation, Mediterranean diet, exercise, weight management
8. Implantable defibrillator (ICD) — if LVEF <35% persists at 40–90 days post-MI despite optimal medical therapy

Key Time Targets (Quality Metrics)

⚠️ Note: An erratum to the 2025 guideline was published (PMID 41212941) — check the official ACC/AHA site for the latest corrected version.