Recommendations for dual antiplatelet therapy

This paper by the American College of Cardiology and American Heart Association provides recommendation on dual antiplatelet therapy (DAPT). 

Dual antiplatelet therapy (DAPT) is a treatment for coronary heart disease involving the use of two antiplatelet (blood thinning) drugs. This is usually given as Aspirin together with either clopidogrel (Plavix), prasugrel (Effient) or ticagrelor (Brilinta). These drugs work by preventing blood from sticking together. It is often given to those at risk of suffering an ischemic event (insufficient blood supply) such as a heart attack. It is also often given after stent implantation (mesh wire structure to treat narrow or weak arteries).

The authors reviewed recent evidence and provided recommendations based on the strength of the evidence.

In general, studies show that a longer DAPT decreases ischemic complications but increases bleeding complications. Thus, a shorter duration of DAPT can be considered for those with lower ischemic risk but high bleeding risk. Based on moderate quality evidence, a daily Aspirin dose of 81 mg (range from 75 to 100 mg) is strongly recommended. Multiple studies show that Aspirin doses of less than 100 mg are associated with less bleeding than higher doses.

Evidence on the use of DAPT in patients with acute coronary syndrome (heart attack or insufficient blood supply to heart) was examined. One trial found that clopidogrel (for up to 1 year) and Aspirin resulted in a 2.1% reduction in ischemic events but also a 1.0% increase in major bleeding. After a stent implantation, moderate quality evidence strongly recommends the use of clopidogrel, prasugrel, or ticagrelor for at least 12 months. Those on medical therapy alone should use clopidogrel or ticagrelor for at least 12 months.

The use of DAPT was also examined in patients with stable ischemic heart disease (with no symptoms for more than 1 year). There is high-quality evidence recommending the use of clopidogrel after bare-metal stent implantation for at least 1 month. For patients with treated with drug-eluting stent, it is strongly recommended based on moderate quality evidence that clopidogrel should be given for at least 6 months. Five studies found that 3 to 6 months DAPT did not increase the risk of blood clotting in the stent when compared with 12 months of DAPT. 

Authors provided recommendations on the duration of DAPT, which is often dependent on the risk of major bleeding, the patient's condition, and history of stent implantation.