What is the work‑up for a patient with ST‑segment‑elevation myocardial infarction (STEMI) who is a candidate for percutaneous coronary intervention (PCI)?

Work-up for Primary PCI in STEMI

The work-up for a STEMI patient proceeding to primary PCI consists of immediate 12-lead ECG acquisition within 10 minutes, aspirin administration, P2Y12 inhibitor loading, anticoagulation, and direct transfer to the catheterization laboratory—bypassing the emergency department entirely. 1

Immediate Actions at First Medical Contact (≤10 Minutes)

ECG and Diagnosis

• Obtain and interpret a 12-lead ECG within 10 minutes of first medical contact to confirm ST-segment elevation or STEMI-equivalent patterns (new LBBB, isolated anterior ST-depression with aVR elevation, hyperacute T-waves). 1
• Initiate continuous ECG monitoring with defibrillator capacity immediately, as 60-92% of life-threatening ventricular arrhythmias occur within the first 24-48 hours. 1, 2, 3
• The moment of ECG-confirmed ST-elevation becomes "time zero" for all subsequent reperfusion decisions. 1

Initial Pharmacotherapy

• Administer aspirin 150-325 mg orally (chewed or soluble/non-enteric-coated) or 250-500 mg IV if the patient cannot swallow—this is mandatory regardless of bleeding risk because mortality benefit supersedes bleeding concerns. 1, 4, 3
• Give morphine sulfate for pain control and anxiety reduction, which also reduces sympathetic drive and myocardial oxygen demand. 3
• Avoid routine supplemental oxygen unless peripheral oxygen saturation is <90%. 1, 3

Pre-PCI Antithrombotic Regimen

P2Y12 Inhibitor Loading

• Administer a potent P2Y12 inhibitor before or at the time of PCI: prasugrel 60 mg loading dose or ticagrelor 180 mg loading dose. 1, 3
• Use clopidogrel 600 mg loading dose only if prasugrel or ticagrelor are unavailable or contraindicated. 1
• For patients with active bleeding or high bleeding risk, defer P2Y12 loading until after diagnostic angiography confirms the need for PCI to minimize unnecessary exposure. 4

Anticoagulation

• Unfractionated heparin (UFH) 100 U/kg IV bolus is the standard anticoagulant; reduce to 60 U/kg if a GPIIb/IIIa inhibitor is used. 1, 4
• Enoxaparin or bivalirudin are acceptable alternatives (Class IIa), but UFH is preferred for its short half-life and reversibility with protamine in bleeding scenarios. 1, 4
• Fondaparinux is contraindicated for primary PCI. 1, 4, 3

Laboratory and Imaging Work-Up

Essential Laboratory Tests

• Obtain baseline troponin, complete blood count, renal function (creatinine/eGFR), and electrolytes immediately. 1
• Fasting lipid profile within 24 hours of presentation to guide statin therapy. 1
• These tests should not delay transfer to the catheterization laboratory—they can be drawn en route or upon arrival. 1, 3

Imaging

• No pre-PCI imaging (echocardiography, CT, etc.) is required or recommended—time is myocardium, and any delay worsens outcomes. 1, 3
• Routine echocardiography should be performed during hospitalization (not pre-PCI) to assess LV/RV function, detect mechanical complications, and exclude LV thrombus. 1

Transfer and Timing Protocols

Direct Catheterization Laboratory Transfer

• Transfer the patient directly to the catheterization laboratory, bypassing the emergency department and coronary care unit. 1, 4
• PCI-capable centers must deliver 24/7 service and perform primary PCI without delay, even during off-hours. 1

Time Targets

• For patients presenting directly to a PCI-capable hospital: door-to-balloon time ≤60 minutes (preferably ≤90 minutes maximum). 1
• For patients requiring transfer: first-medical-contact-to-device time ≤120 minutes. 1, 4
• If anticipated PCI delay exceeds 120 minutes, fibrinolysis should be initiated within 10-30 minutes of diagnosis instead. 1, 4

Mandatory Primary PCI Regardless of Delay

Primary PCI is indicated irrespective of time from symptom onset in the following scenarios:

• Cardiogenic shock or acute severe heart failure. 1, 3
• Contraindications to fibrinolytic therapy (active bleeding, recent stroke, terminal illness). 1, 4
• Failed fibrinolysis (persistent symptoms or <50% ST-segment resolution at 60-90 minutes). 1, 4

Pre-Hospital and EMS Protocols

EMS Responsibilities

• EMS personnel must be trained and equipped to perform and interpret 12-lead ECG with telemetry capability to transmit to the receiving hospital. 1
• Pre-hospital STEMI diagnosis allows immediate catheterization laboratory activation during ambulance transfer, reducing treatment delays and mortality. 1
• Regional networks with written STEMI management protocols should coordinate EMS, non-PCI hospitals, and PCI centers to optimize reperfusion delivery. 1

Pre-Hospital Medication Administration

• Aspirin and anticoagulation can be administered in the ambulance after STEMI diagnosis. 1
• P2Y12 inhibitor administration in the ambulance (versus in-hospital) is being studied but is not yet standard practice. 5

Critical Pitfalls to Avoid

• Never delay primary PCI to obtain additional imaging, consultations, or to "stabilize" non-life-threatening conditions—the mortality risk from untreated STEMI exceeds procedural risks. 1, 4, 3
• Do not administer nitrates to patients who have taken phosphodiesterase-5 inhibitors within 24-48 hours due to risk of severe hypotension. 3
• Do not withhold aspirin or P2Y12 inhibitors because of bleeding concerns—the immediate threat of stent thrombosis is greater than manageable bleeding. 4
• Do not withhold reperfusion therapy based on age alone—elderly patients derive similar relative benefit from primary PCI. 3
• Avoid routine thrombus aspiration and deferred stenting—both are contraindicated in contemporary practice. 1, 4

Technical Considerations During PCI

• Use routine radial arterial access to minimize bleeding complications. 1, 4
• Implant drug-eluting stents (DES) as the default device. 1, 4
• Evaluate severe non-infarct-related artery (non-IRA) stenoses before hospital discharge, either during the index PCI or in a staged procedure; in cardiogenic shock, perform non-IRA PCI during the index procedure. 4

Post-PCI Monitoring

• Monitor all STEMI patients for at least 24 hours after reperfusion therapy, with extended monitoring up to 48 hours reasonable given that 8-10% of ventricular arrhythmias occur after the initial 24 hours. 2
• Continue aspirin 75-100 mg daily plus prasugrel 10 mg daily or ticagrelor 90 mg twice daily for 12 months. 1, 3