- Aspirin 325 mg
- Clopidogrel (Plavix) 600 mg, then 75 mg once daily OR Ticagrelor (Brilanta) 180 mg, then 90 mg twice daily
- Unfractionated heparin bolus of 60 units/ kg not exceeding 4,000 units, followed by an infusion of 12 units/kg/hour, with monitoring of the activated partial thromboplastin time every 6 hours with a goal value of 50 to 70 seconds or 1.5 to 2.5 times control.
Aspirin irreversibly acetylates the enzyme cyclooxygenase-1, blocking intraplatelet formation of thromboxane A2, a potent platelet aggregator and endothelial vasoconstrictor.
Heparin binds to antithrombin and induces a conformational change, causing rapid inhibition of factor IIa (thrombin), factor IXa, and factor Xa, thus preventing further thrombus propagation (FIGURE 4). An intravenous bolus of 60 units/kg produces a time to peak of 5 to 10 minutes and a half-life of 30 to 60 minutes.
The CURE trial randomized 12,526 patients with non-ST-elevation ACS to receive clopidogrel or placebo in addition to standard therapy. Clopidogrel was associated with a 20% lower rate of cardiovascular death, myocardial infarction, or stroke in both low- and high-risk patients regardless of whether an invasive or conservative strategy was pursued.
However, patients who underwent coronary artery bypass grafting (CABG) had a 53% higher risk of bleeding (an absolute risk of 3.3%) if they received clopidogrel within 5 days of the surgery. This has led to the practice in some centers of delaying giving clopidogrel until after the coronary anatomy has been defined.