Acute Coronary Syndrome

Dual antiplatelet therapy
  1. Aspirin 325 mg
  2. Clopidogrel (Plavix) 600 mg, then 75 mg once daily OR  Ticagrelor (Brilanta) 180 mg, then 90 mg twice daily
  1. 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.
Percutaneous Intervention


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.