Sandbox:DN

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Dima Nimri, M.D. [2]

Overview

Dual antiplatelet therapy (or DAPT) refers to the combination of aspirin and a P2Y12 receptor antagonist. DAPT is approved for SIHD and interventions for ACS, such as stent placement following PCI or CABG. The duration of treatment with DAPT for each of these categories differs and guidelines for treatment have been updated in the 2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease. Much of the studies done on DAPT compared the use of different types of P2Y12 receptor antagonists, the dosage of drugs, as well as the duration of treatment. The current consensus is that the use of DAPT is associated with decreased risk of stent thrombosis, MI and stroke. However, the benefits of treatment should be weighed against the increased risk of major bleeding in certain patient populations.

Types and Dosage of Drugs

Aspirin

Aspirin 81 mg once daily (range 75-100 mg) is used in all patients with SIHD, stent placement following PCI or CABG. The use of aspirin should be continued indefinitely.

P2Y12 Inhibitors

There are several P2Y12 inhibitors currently on the market and they are given in the following doses:

• Clopidogrel: 75 mg once daily
• Ticagrelor: 90 mg once daily
• Prasugrel: 10 mg once daily

The drug of choice and duration of treatment depends on the medical condition and current recommendations.

Recommendations

The 2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease includes recommendations for ACS treated with medical therapy and/or PCI, ACS treated with CABG, as well as stable ischemic heart disease:

• Unstable Angina/ NSTEMI Treated with Medical Therapy Alone
• STEMI Treated with Medical Therapy Alone
• Following PCI
• CABG for NSTEMI
• CABG for STEMI
• Stable Ischemic Heart Disease

The DAPT score

The DAPT score is a risk score derived from the DAPT Trial. It has been designed as a helpful tool for the continuation of dual antiplatelet therapy following PCI and the insertion of a drug-eluting stent (DES). A low DAPT score is associated with a higher risk of bleeding and a smaller reduction in ischemia. On the other hand, a high DAPT score translates into a greater reduction in ischemia, with a smaller risk of bleeding. The cut-off point has been set at the value of 2, such that a score of ≥2 is associated with a favorable benefit-to-risk ratio for prolonged DAPT, while a score of less than 2 is associated with an unfavorable benefit-to-risk ratio.

Variable	Points
Age ≥75 years	-2
Age 65 to less than 75 years	-1
Age less than 65 years	0
Current cigarette smoker	1
Diabetes Mellitus	1
MI at presentation	1
Prior PCI or prior MI	1
Prior PCI or prior MI	1
Stent diameter less than 3mm	1
Paclitaxel-eluting stent	1
CHF or LVEF less than 30%	2
Saphenous vein graft PCI	2