Antiplatelet in ACS

All Patients

• Aspirin, 325 mg daily, should be used in all patients except those allergic to aspirin.  Lower doses of aspirin (81-160 mg) can be implemented long term.  Clopidogrel 300 to 600 mg load followed by 75 mg daily should be administered to all patients allergic to aspirin. 

High Risk Patients

Defined as patients with elevated cardiac markers (troponin or CKMB), dynamic ECG changes (i.e. ST changes with chest pain that resolve with resolution of pain) and recurrent chest pain on standard therapy. Patients with diabetes and ACS are considered high risk.  The highest risk patients are those with recurrent chest pain despite treatment with aspirin and heparin and those with dynamic ST changes on ECG.

• Glycoprotein (GP) IIb-IIIa inhibitors (tirofiban or eptifibatide) should be administered in addition to aspirin and heparin.  We recommend, in particular, that patients with recurrent chest who are being urgently transferred to FAHC be treated before transfer with tirofiban or eptifibatide.  Patients with diabetes and ACS exhibit profound additional benefit from the adjunctive use of tirofiban or eptifibatide.
• Current evidence suggests that these patients are best treated invasively.  Thus, these patients should be transferred to a tertiary care unit for cardiac catheterization.  Unless coronary anatomy is known, we recommend that clopidogrel not be administered until cardiac catheterization is performed.  Up to 30% of these patients will require surgical revascularization and the risk of bleeding perioperatively is greater in those treated with clopidogrel.

Low to Moderate Risk Patients

• Aspirin and heparin (enoxaparin or unfractionated heparin) should be administered.  Recurrent chest pain stratifies the patient as high risk and tirofiban or eptifibatide should be administered before urgent transfer to a tertiary care center.
• If non-invasive evaluation (stress testing) is planned, clopidogrel should be considered in combination with aspirin.
• If invasive evaluation is planned, do not begin clopidogrel until or unless coronary anatomy is known (see above for bleeding risk with cardiac surgery).
• Clopidogrel (300-600 mg loading dose followed by 75 mg daily) should be given to patients scheduled for percutaneous coronary intervention, (300 mg > 12 hours before the procedure and 500 mg < 12 hours before theprocedure). Patients with chronic total occlusion should not be loaded with clopidogrel prior to the procedure.
• Clopidogrel 300 mg followed by 75mg daily should be administered in addition to aspirin and heparin in patients with know coronary anatomy and not planned to undergo CABG.

In patients exposed to clopidogrel in whom elective cardiac surgery (or any surgical procedure) is planned, the drug should be withheld for 5 to 7 days before surgery.

In patients undergoing percutaneous coronary intervention clopidogrel should be administered for at least 1 month and for up to 12 months in patients not at high risk for bleeding.  Continued treatment with clopidogrel after 1 month is associated with a 3% absolute reduction in the incidence of cardiac events and a 2% absolute increase in bleeding complications (primarily associated with surgical procedures).

In patients treated with clopidogrel plus aspirin greater than 30 days, the dose of aspirin should be decreased to 81 or 160 mg a day.