Prolonged dual antiplatelet therapy (DAPT) after implantation of newer-generation drug-eluting stents (DES) involves a tradeoff between reductions in stent thrombosis and myocardial infarction (MI) and increases in major hemorrhage. This according to a primary analysis from a review off 11 randomized controlled trials (RCTs) that enrolled 33,051 patients with coronary artery disease who received predominantly newer-generation DES. Researchers found:

• Use of DAPT for 12 months resulted in no significant differences in incidence of death (OR=1.17), major hemorrhage (OR=0.87), MI (OR=0.87), or stent thrombosis (OR=0.87) when compared with use for 3 to 6 months.

• Use of DAPT for 18 to 48 months was associated with no difference in incidence of all-cause death (OR=1.14) but was associated with increased major hemorrhage (OR=1.58), decreased MI (OR=0.67), and decreased stent thrombosis (OR=0.42), when compared with use for 6 to 12 months.

• A risk-benefit analysis found 3 fewer stent thromboses and 6 fewer MIs but 5 more major bleeds per 1,000 patients treated with prolonged DAPT.

• Use of DAPT >1 year after MI reduced the composite risk of cardiovascular death, MI or stroke (HR=0.84) but increased major bleeding (HR=2.32).

Citation: Bittl JA, Baber U, Bradley SM, Wijeysundera DN. Duration of dual antiplatelet therapy: A systematic reviews for the 2016 ACC/AHA Guideline focused update on duration of dual antiplatelet therapy in patients with coronary artery disease: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. [Published online ahead of print March 29, 2016]. Circulation. doi:10.1161/CIR.0000000000000405.

Commentary: In the late 1990’s, antiplatelet therapy was used for 4 weeks after PCI to decrease the rate of stent thrombosis. As time went on, 4 weeks of antiplatelet therapy was extended to an indefinite period as it became apparent that the risk of stent thrombosis extended beyond 6 months. The rate of stent thrombosis has changed over the last decade as the types of drug-eluting stents have changed. The rate of stent thrombosis in the newer DES are about half that of the older stents. The conclusion of this meta-analysis is that patients should be given DAPT for 3 to 6 months to prevent early and late stent-related thrombotic events. Continuation of DAPT past 12 months means a tradeoff between lowering the risk of stent thrombosis and increasing the risk of major bleeding. The authors conclude, “the declining risk of late stent thrombosis with newer-generation DES and the inability to predict life-threatening bleeding limits the appeal of 18 to 48 months of DAPT over 6 to 12 months of therapy.” —Neil Skolnik, MD