Latest Management of Acute Myocardial Infarction
Primary percutaneous coronary intervention (PCI) within 90–120 minutes of ECG diagnosis is the definitive treatment for STEMI, with immediate aspirin plus a potent P2Y12 inhibitor (prasugrel or ticagrelor) started before or during the procedure. 1
Immediate Diagnosis and Triage
Obtain and interpret a 12-lead ECG within 10 minutes of first medical contact to distinguish STEMI from non-ST elevation acute coronary syndrome. 2, 1 This is the critical decision point that determines your reperfusion strategy.
- Initiate continuous ECG monitoring with defibrillator capability immediately in all suspected cases to detect and treat life-threatening arrhythmias. 2, 1
- Do not routinely administer supplemental oxygen unless oxygen saturation is <90%—routine oxygen therapy is contraindicated. 2, 1
Reperfusion Strategy: The Time-Critical Decision
For STEMI: Primary PCI is Mandatory
Transfer the patient directly to the catheterization laboratory, bypassing the emergency department entirely, to minimize door-to-balloon time. 2, 1 The clock starts at ECG confirmation, not symptom onset.
Primary PCI must be performed within 90–120 minutes of STEMI diagnosis. 1 This represents the most recent guideline standard and supersedes older 12-hour symptom-based windows for decision-making.
Technical PCI Standards:
- Use radial artery access preferentially—this is now Class I, Level A evidence. 1
- Implant drug-eluting stents as standard of care for culprit lesions. 2, 1
- Routine thrombus aspiration is contraindicated (Class III). 1
- Deferred stenting is contraindicated (Class III). 1
When PCI Cannot Be Achieved Within 120 Minutes
If primary PCI is unavailable within the 120-minute window, initiate fibrinolytic therapy immediately—ideally within 10 minutes of diagnosis. 1 This is a firm time-based algorithm, not a subjective decision.
- Use fibrin-specific agents: tenecteplase, alteplase, or reteplase. 1, 3
- Administer fibrinolysis in the pre-hospital setting when possible to reduce time to reperfusion. 1
- All patients receiving fibrinolysis must be transferred immediately to a PCI-capable center for planned coronary angiography 2–24 hours after successful thrombolysis. 1
Critical contraindication: Fibrinolytic therapy is absolutely contraindicated in patients with acute stroke, regardless of anticipated PCI delay. 4 Prolonged CPR >10 minutes is a relative contraindication. 3
Antithrombotic Therapy: The Dual Pathway
For Primary PCI Patients
Aspirin 150–325 mg (oral or IV) immediately on presentation. 1
A potent P2Y12 inhibitor must be given before or at the time of PCI:
- Prasugrel 60 mg loading dose (preferred in most patients) 2, 1
- Ticagrelor 180 mg loading dose (alternative to prasugrel) 2, 1
- Clopidogrel is reserved only when prasugrel or ticagrelor are unavailable or contraindicated—this is now downgraded to Class IIb. 1
Unfractionated heparin (weight-adjusted IV bolus) is the preferred anticoagulant during PCI. 1 Enoxaparin or bivalirudin may be used as alternatives. 1 Fondaparinux is contraindicated for primary PCI. 1
For Fibrinolysis Patients
Aspirin (oral or IV) is administered concomitantly with fibrinolysis. 1, 3
Clopidogrel (not prasugrel or ticagrelor) is given after fibrinolysis. 1, 3 This is a critical distinction—the potent P2Y12 inhibitors are reserved for the PCI pathway.
Enoxaparin IV followed by subcutaneous dosing is preferred over unfractionated heparin in the fibrinolysis pathway. 1
Long-Term DAPT
Continue aspirin plus prasugrel or ticagrelor for 12 months after the acute event. 2, 1 This represents the standard duration based on one-year DAPT trials. 2
Co-prescribe a proton-pump inhibitor for patients at high gastrointestinal bleeding risk. 1
Multivessel Disease Management
In clinically stable patients with multivessel disease, severe non-infarct-related artery stenoses should be treated before hospital discharge, either during the index PCI or in a staged procedure. 1 This represents a shift toward complete revascularization rather than culprit-only strategies.
Use angiographic assessment or fractional flow reserve (FFR) to guide revascularization decisions in non-culprit vessels. 1
In cardiogenic shock, PCI of non-infarct-related lesions may be performed during the index procedure. 1
Post-Cardiac Arrest STEMI: A Special Algorithm
For resuscitated patients with ST-elevation on post-resuscitation ECG, primary PCI is mandatory. 2, 3 Do not delay for neurological assessment.
Initiate targeted temperature management early in unresponsive patients. 2, 3 However, pre-hospital cooling with rapid infusion of cold IV fluids is not recommended. 2, 3
If no ST-elevation but ongoing ischemic suspicion exists, perform urgent coronary angiography within 2 hours after excluding non-coronary causes. 1
Post-Procedure Medical Management
Initiate oral beta-blocker once hemodynamically stable (avoid IV beta-blockers in the acute phase). 4
Start ACE inhibitor within 24 hours if no contraindications, particularly with anterior MI, heart failure, or LVEF ≤40%. 4
Begin high-intensity statin therapy immediately. 4
MINOCA: The Diagnostic Challenge
A substantial proportion of STEMI patients have no significant coronary stenosis on angiography (MINOCA). 2, 1 This requires a different diagnostic and therapeutic approach.
Perform additional diagnostic tests—cardiac MRI, intravascular ultrasound (IVUS), or optical coherence tomography (OCT)—to identify the etiology (spontaneous coronary artery dissection, coronary vasospasm, myocarditis, takotsubo cardiomyopathy). 2, 1 Treatment must be tailored to the specific etiology rather than following standard STEMI protocols.
Critical Pitfalls to Avoid
Do not perform routine PCI of an occluded infarct-related artery >48 hours after STEMI onset in asymptomatic patients—this is contraindicated (Class III, Level A). 2, 1
Never use GP IIb/IIIa inhibitors in patients with acute stroke, as they dramatically increase intracranial hemorrhage risk. 4
Avoid triple antithrombotic therapy (aspirin + P2Y12 inhibitor + anticoagulation) in the immediate post-procedure period unless absolutely necessary. 4
System-Level Quality Indicators
Establish regional STEMI networks with 24/7 high-volume PCI centers to ensure timely reperfusion. 2, 1 Written, standardized protocols linking emergency medical services and hospitals should be developed. 1
Measure and audit validated quality indicators (door-to-balloon time, reperfusion rates, mortality) to continuously improve care. 2, 1 The gap between guideline-based treatment and actual care remains significant in many systems. 2