What is the dose for a heparin bolus in Acute Coronary Syndrome (ACS)?

From the Guidelines

The dose for a heparin bolus in Acute Coronary Syndrome (ACS) is 60 units/kg (maximum 5,000 units) for unstable angina and non-ST-segment elevation myocardial infarction, and 60 units/kg (maximum 4,000 units) when given in conjunction with fibrinolytic agents for treatment of ST-segment elevation myocardial infarction.

Key Points

• The American College of Cardiology recommends a heparin bolus of 60 to 70 units/kg (maximum 5,000 units) followed by an infusion of 12 to 15 units/kg/h (maximum 1,000 units/h) for unstable angina and non-ST-segment elevation myocardial infarction 1.
• When heparin is given in conjunction with fibrinolytic agents for treatment of ST-segment elevation myocardial infarction, the recommended bolus is about 60 units/kg (maximum 4,000 units) and the infusion is 12 units/kg/h (maximum of 1,000 units/kg/h) 1.
• Weight-based dosing of 60 to 70 U/kg of heparin is used in primary PCI, rather than fixed bolus or ACT-guided dosing 1.
• The effective biological half-life of heparin increases from ≈30 minutes after an IV bolus of 25 U/kg to 60 minutes with an IV bolus of 100 U/kg, and unfractionated heparin has heterogeneous anticoagulation effects and multiple limitations 1.
• Monitoring of aPTT and full weight adjustment of heparin may decrease the risk of non-cerebral bleeding complications 1.

From the FDA Drug Label

Table 1: Recommended Adult Full-Dose Heparin Regimens for Therapeutic Anticoagulant Effect *Based on 68 kg patient METHOD OF ADMINISTRATION FREQUENCY RECOMMENDED DOSE Intermittent Intravenous Injection Initial Dose 10,000 units, either undiluted or in 50 to 100 mL of 0. 9% Sodium Chloride Injection, USP

The dose for a heparin bolus in Acute Coronary Syndrome (ACS) is 10,000 units by intermittent intravenous injection, as an initial dose. 2

From the Research

Heparin Bolus Dose in Acute Coronary Syndrome (ACS)

• The recommended initial heparin bolus dose for patients with ACS is 60 U/kg (maximum, 4000 U) when administered with alteplase for ST-elevation myocardial infarction 3.
• For patients with non-ST elevation myocardial infarction and unstable angina, an initial bolus of 60 to 70 U/kg (maximum, 5000 U) is recommended 3.
• A study published in 2008 found that the most frequent bolus dose used in practice was 5,000 U (42.7%) 4.
• Another study published in 1995 compared a standard-care nomogram with a weight-adjusted nomogram and found that the weight-adjusted nomogram, which used an 80 U/kg IV bolus, achieved adequate anticoagulation more rapidly 5.
• The goal of heparin therapy is to achieve an activated partial thromboplastin time (aPTT) of 50 to 70 seconds 3.

Factors Affecting Heparin Dosing

• Excess weight-adjusted heparin bolus or infusion dose is associated with an increased risk of major bleeding 4.
• Factors such as age and female sex are strongly associated with excess weight-adjusted dosing 4.
• The relationship between weight-adjusted heparin dose and major bleeding does not vary independently by sex or age 4.

Recent Guidelines and Recommendations

• Recent guidelines specify that a bolus of unfractionated heparin is recommended during percutaneous coronary intervention in certain circumstances, such as if the patient is receiving a non-vitamin K antagonist oral anticoagulant or if the international normalized ratio is <2.5 in a patient being treated with a vitamin K antagonist 6.