DAPT Substudy: Score to Personalize Optimal Dual Antiaggregation Therapy Duration

Original Title: Individualizing Treatment Duration of Dual Antiplatelet Therapy after Percutaneous Coronary Intervention: An Analysis from the DAPT Study. Presenter: Yeh RW.

Optimal dual antiplatelet therapy duration for patients receiving stents has started to become clearer, but a new scoring method (DAPT Score) may help single out patients who could either benefit or suffer from extended thienopyridine therapy.

The DAPT study (published in the New England Journal of Medicine last year) was designed in response to an FDA request to examine short vs. long term antiplatelet treatment in more than 25,000 PCI patients receiving conventional bare metal stents vs. drug eluting stents. Its main findings showed lower risks of stent thrombosis and MACCE, but a higher risk of bleeding when treatment was longer than 1 year.

The study analyzed 11,648 trial participants who completed the twelve months of dual antiaggregation therapy without incident and were randomized to continue taking aspirin with or without a thienopyridine. Researchers used multivariable models to predict the composite of infarction or stent thrombosis (ischemia model) and GUSTO moderate/severe bleeding, introducing this information in the form of a positive or negative whole number they called the DAPT Score.
Older age exclusively predicted increased bleeding risk while other factors resulted exclusive predictorsof more ischemic events, such as a history of PCI or infarction, stent diameter, chronic heart failure or left ventricular ejection fraction (LVEF) < 30%.
The DAPT Score ranges from -2 to 10 and comprises the following factors: age, diabetes, smoking habit, PCI or MI history, presence of chronic heart failure or LVEF < 30%, MI at presentation, vein graft PCI and stent diameter.

A DAPT Score of 2 was considered the cutoff value to know whether a patient should or should not receive extended therapy. Among those receiving extended dual antiaggregation therapy vs. placebo, patients with scores of <2 had a higher incidence of bleeding (P < .001), while those with scores of ≥ 2 had lower incidences of both combined ischemic events and death (P < .001 for both).

Among patients who have not had a major ischemic or bleeding event within the first year after PCI, the DAPT Score identified patients for whom ischemic benefits outweighed bleeding risks, and other patients where bleeding risks outweighed ischemic benefits.