Anticoagulation Therapy in Myocardial Infarction
Recommendations for Anticoagulation
- The American College of Cardiology/American Heart Association (ACC/AHA) recommends heparin or enoxaparina as anticoagulants of choice for patients with myocardial infarction, with a bolus of 60 U/kg (maximum 4000 U) followed by an infusion of 12 U/kg/hour (maximum 1000 U/hour) for heparin, and 1 mg/kg every 12 hours for enoxaparina, in patients under 75 years without significant renal dysfunction 1, 2, 3
- For patients with ST-elevation myocardial infarction (STEMI), heparin or enoxaparina can be used, with a target aPTT of 1.5-2.0 times control (50-70 seconds) for 48 hours 1, 2, 3
- For patients with non-ST-elevation myocardial infarction (NSTEMI), heparin or enoxaparina can be used, with a bolus of 60-70 U/kg (maximum 5000 U) followed by an infusion of 12-15 U/kg/hour for heparin, and 1 mg/kg twice daily for enoxaparina 1, 2, 5
Considerations for Low Molecular Weight Heparin (LMWH) Use
- The ACC/AHA guidelines recommend against using LMWH in patients over 75 years receiving thrombolytic therapy due to increased risk of bleeding 3, 4
- LMWH should not be used as an alternative to unfractionated heparin in patients with significant renal dysfunction receiving thrombolytics 3, 4
Special Considerations
- In patients with right ventricular infarction and hypotension, avoid aggressive initial anticoagulation until hemodynamic stabilization is achieved with intravenous fluids 7
- Bemiparina should not be administered in patients with active uncontrolled bleeding, such as those with recent evacuation of vesical clots 6