Impact of Optimal Medical Therapy in the Dual Antiplatelet Therapy Study

Area of Science:

• Cardiovascular Medicine
• Clinical Trials
• Pharmacology

Background:

• Optimal medical therapy (OMT) and dual antiplatelet therapy (DAPT) improve outcomes in coronary heart disease.
• The impact of OMT on the effectiveness of DAPT remains unclear.

Purpose of the Study:

• To investigate whether optimal medical therapy (OMT) modifies the treatment effect of extended dual antiplatelet therapy (DAPT) in patients post-coronary stenting.
• To evaluate the efficacy and safety of continued thienopyridine therapy versus placebo in patients receiving or not receiving OMT.

Main Methods:

• The DAPT Study randomized 11,648 patients to 18 months of continued thienopyridine or placebo after an initial year of DAPT.
• OMT was defined as concurrent use of statin, beta-blocker, and ACE inhibitor/ARB.
• Outcomes included myocardial infarction, major adverse cardiovascular events, and bleeding.

Main Results:

• Continued thienopyridine reduced myocardial infarction regardless of OMT status (interaction P=0.103).
• Rates of major adverse cardiovascular and cerebrovascular events were reduced by continued thienopyridine, with a significant effect observed in patients not on OMT (HR, 0.63; P<0.001).
• Bleeding rates increased with continued thienopyridine in patients on OMT (HR, 2.13; P<0.001), but not significantly in those off OMT (HR, 1.30; P=0.189).

Conclusions:

• Continued thienopyridine therapy effectively reduces myocardial infarction rates in patients with coronary heart disease, irrespective of OMT.
• The benefits of extended DAPT on major adverse cardiovascular events and the associated bleeding risk should be considered in the context of OMT use.