From the Guidelines
Primary percutaneous coronary intervention (PCI) is the preferred treatment for STEMI if it can be performed within 90 minutes of first medical contact, as it has been shown to be superior to fibrinolytic therapy in reducing morbidity and mortality. The American College of Cardiology/American Heart Association (ACC/AHA) guideline for the management of STEMI outlines that primary PCI should be performed timely in patients with acute STEMI 1. If primary PCI cannot be performed in a timely manner, timely fibrinolytic therapy is an acceptable alternative therapeutic strategy. The treatment of STEMI requires immediate reperfusion therapy to restore blood flow to the affected coronary artery.
Some key points to consider in the treatment of STEMI include:
- Aspirin (162-325 mg loading dose, then 81 mg daily) and a P2Y12 inhibitor such as ticagrelor (180 mg loading dose, then 90 mg twice daily) or prasugrel (60 mg loading dose, then 10 mg daily) should be given immediately 1.
- Anticoagulation with unfractionated heparin (60 units/kg IV bolus, maximum 4000 units, followed by 12 units/kg/hour infusion) or enoxaparin (30 mg IV bolus followed by 1 mg/kg subcutaneously every 12 hours) is also essential.
- Additional medications include high-intensity statins (atorvastatin 80 mg or rosuvastatin 40 mg daily), beta-blockers (metoprolol 25-50 mg orally every 6 hours), and ACE inhibitors or ARBs for patients with anterior MI, heart failure, or reduced ejection fraction.
- Supplemental oxygen should be provided if oxygen saturation is below 90%.
- Rapid reperfusion is critical because "time is muscle" - each minute of delay increases myocardial damage and mortality risk, as noted in the European Society of Cardiology guidelines 1.
- Following acute treatment, dual antiplatelet therapy should continue for at least 12 months, with other medications typically continued indefinitely.
It's worth noting that while the 2005 European Society of Cardiology guidelines provide valuable insights into the treatment of STEMI, the more recent 2017 ACC/AHA guideline 1 takes precedence in guiding current clinical practice.
From the FDA Drug Label
Prasugrel tablets are indicated to reduce the rate of thrombotic CV events (including stent thrombosis) in patients with acute coronary syndrome (ACS) who are to be managed with percutaneous coronary intervention (PCI) as follows: Patients with unstable angina (UA) or non-ST-elevation myocardial infarction (NSTEMI) Patients with ST-elevation myocardial infarction (STEMI) when managed with primary or delayed PCI.
The treatment of STEMI with prasugrel involves a loading dose of 60 mg followed by a daily dose of 10 mg, in addition to aspirin (75 mg to 325 mg) daily 2. The loading dose can be administered at the time of diagnosis in STEMI patients presenting within 12 hours of symptom onset, although most received prasugrel at the time of PCI.
- Key considerations:
- Prasugrel has been shown to reduce the rate of a combined endpoint of cardiovascular death, nonfatal myocardial infarction (MI), or nonfatal stroke compared to clopidogrel in STEMI patients managed with PCI.
- The difference between treatments was driven predominantly by MI, with no difference on strokes and little difference on CV death.
- Prasugrel may be administered with or without food.
- Important warnings:
- Prasugrel can cause significant, sometimes fatal, bleeding.
- Do not use prasugrel in patients with active pathological bleeding or a history of transient ischemic attack (TIA) or stroke.
- In patients ≥75 years of age, prasugrel is generally not recommended, because of the increased risk of fatal and intracranial bleeding and uncertain benefit, except in high-risk situations 2.
From the Research
Treatment of STEMI
The treatment of ST-segment elevation myocardial infarction (STEMI) involves various pharmacological and interventional approaches.
- Antithrombotic therapy, including antiplatelet and anticoagulant agents, is the cornerstone of pharmacological treatment to optimize clinical outcomes in patients with STEMI undergoing primary percutaneous coronary intervention (PPCI) 3.
- Dual antiplatelet therapy with aspirin and an oral P2Y12-receptor inhibitor is pivotal for the acute and long-term treatment of patients with STEMI undergoing PPCI 3.
- The optimal timing for the initiation of dual antiplatelet therapy is still uncertain, but pretreatment with P2Y12 inhibitors in combination with aspirin has been shown to be associated with better outcomes 4.
Anticoagulant Therapy
- Intravenous anticoagulant drugs available for PPCI include the indirect thrombin inhibitors unfractionated heparin and low-molecular-weight heparin, and the direct thrombin inhibitor bivalirudin 3.
- Enoxaparin, a low molecular weight heparin, may provide better outcomes when used for PPCI compared to unfractionated heparin, with a reduction in all ischemic complications and no increase in major bleeding 5.
Aspirin Therapy
- The optimal dose of aspirin for STEMI patients is unclear, but studies suggest that an initial dose of 162 mg may be as effective as and perhaps safer than 325 mg for the acute treatment of STEMI 6.
- Aspirin loading may attenuate the protective effects of other interventions, such as statins, ticagrelor, and ischemic postconditioning, on infarct size limiting effects 7.
P2Y12 Inhibitors
- Prasugrel and ticagrelor provide a more prompt, potent, and predictable antiplatelet effect compared with clopidogrel, which translates into better clinical outcomes 3.
- Pretreatment with P2Y12 inhibitors in combination with aspirin has been shown to be associated with a reduction in definite stent thrombosis, all-cause death, and cardiogenic shock, with no significant increase in major bleeding events 4.