What treatment can a patient with Acute Coronary Syndrome (ACS) and positive troponin I expect in transit for Percutaneous Coronary Intervention (PCI)?

Pre-Hospital and Transit Management for ACS with Positive Troponin I En Route to PCI

A patient with ACS and positive troponin I should immediately receive aspirin 162-325 mg (non-enteric-coated, chewable), a P2Y12 inhibitor loading dose (preferably ticagrelor 180 mg or clopidogrel 300-600 mg), and parenteral anticoagulation (enoxaparin 1 mg/kg SC or bivalirudin) during transport to PCI. 1

Immediate Antiplatelet Therapy

Aspirin Administration

• Non-enteric-coated, chewable aspirin 162-325 mg should be given immediately upon recognition of ACS, regardless of prior aspirin use 1
• This should occur as soon as possible after presentation, ideally in the pre-hospital setting 1
• Aspirin is mandatory prior to PCI and reduces ischemic complications 1

P2Y12 Inhibitor Loading

Ticagrelor is the preferred first-line P2Y12 inhibitor for patients with positive troponin (high-risk features) being transported for PCI 1:

• Ticagrelor 180 mg loading dose should be administered pre-hospital 1
• Ticagrelor is recommended over clopidogrel for early invasive strategy 1, 2

Clopidogrel is the alternative when ticagrelor is unavailable or contraindicated 1:

• Clopidogrel 300-600 mg loading dose (600 mg preferred for faster onset) 1
• The 600 mg loading dose provides more consistent platelet inhibition, though it increases bleeding risk slightly 1, 3

Prasugrel should NOT be given pre-hospital because it requires knowledge of coronary anatomy and is contraindicated in patients with prior stroke/TIA 1

Parenteral Anticoagulation During Transport

Anticoagulation must be initiated immediately in addition to antiplatelet therapy, regardless of treatment strategy 1, 2:

First-Line Options

Enoxaparin is highly recommended as first-line anticoagulation 1, 2:

• 1 mg/kg subcutaneous every 12 hours (or 1 mg/kg once daily if creatinine clearance <30 mL/min) 1
• Continue for duration of hospitalization or until PCI is performed 1
• An initial 30 mg IV loading dose may be used in selected patients 1

Bivalirudin is recommended for high bleeding risk patients or elderly 1:

• 0.10 mg/kg loading dose followed by 0.25 mg/kg/hour infusion 1
• Particularly appropriate for patients at high bleeding risk 1
• Continue until PCI is performed 1, 4

Alternative Option

Unfractionated heparin (UFH) if enoxaparin is not available 1, 2:

• 70-100 units/kg IV bolus (weight-adjusted) 2
• Continue for 48 hours or until PCI is performed 1

Critical warning: Fondaparinux should NOT be used if primary PCI is planned, as it increases catheter thrombosis risk 1

Additional Medications During Transport

Pain Management

Opioids (morphine) should be titrated carefully according to pain evaluation 1:

• Use the minimum effective dose, as opioids may interfere with oral antiplatelet absorption 1
• Nitroglycerin can be used for ongoing chest pain 5

GP IIb/IIIa Inhibitors (Conditional)

GP IIb/IIIa inhibitors may be considered in specific high-risk scenarios 1:

• Only in patients with extensive infarct presenting early (<2 hours after symptom onset) 1
• Preferred agents: eptifibatide or tirofiban 1
• Only use in patients at LOW bleeding risk 1
• This is a Class IIb recommendation (may be considered, not routine) 1

Critical Pitfalls to Avoid

Medication Errors

• Never give prasugrel pre-hospital - coronary anatomy must be known first 1
• Never use fondaparinux if PCI is planned - requires additional UFH bolus and increases catheter thrombosis 1
• Do not use immediate-release nifedipine without beta-blocker therapy 1
• Avoid IV beta-blockers in patients with risk factors for shock 1

Dosing Considerations

• If patient already on clopidogrel 75 mg daily, give an additional 300 mg loading dose before PCI 1
• If enoxaparin given <8-12 hours before PCI, give additional 0.3 mg/kg IV dose at time of PCI 1
• If fondaparinux was mistakenly given, must administer 85 units/kg UFH IV immediately before PCI (60 units/kg if GP IIb/IIIa inhibitor used) 1

Patient-Specific Contraindications

• Withhold all antithrombotic therapy if high bleeding risk or uncertain STEMI diagnosis 1
• Aspirin allergy: use clopidogrel 300 mg loading dose as sole antiplatelet 1

Monitoring During Transport

Continuous ECG monitoring and vital signs assessment are mandatory 1:

• Monitor for hemodynamic instability or signs of heart failure 1
• Assess for cardiogenic shock, which may require transfer to facility with circulatory support capability 1
• Document pain response to therapy 1

The goal is rapid transport to a facility with 24/7 PCI capability, as time to revascularization directly impacts outcomes 1, 2