**3. Indications for DAPT**

#### **3.1 Atrial fibrillation**

About 40% of patients with atrial fibrillation have a high risk of having CAD. DAPT prevents the risk of thrombotic complications in patients with atrial fibrillation that are undergoing percutaneous coronary intervention [24]. DAPT is preferable to triple therapy with an oral anticoagulant (OAC) due to low risk of bleeding and other thrombotic complications [24–26]. Clopidogrel is a drug of first choice; however, prasugrel and ticagrelor have been recently approved for treating patients with high ischemic risk and high risk of hemorrhage and stent thrombosis associated with clopidogrel [27].

However, prasugrel is contraindicated in patients undergoing treatment with aspirin and OAC due to the risk of hemorrhage [28].

#### **3.2 Acute coronary syndrome**

DAPT can be prescribed for prevention of ACS and other adverse cardiovascular (CVS) events. A combination of aspirin and ticagrelor or prasugrel is commonly recommended for treating patients with ACS within 6–12 months [29, 30]. DAPT is recommended for treating patients with ACS and atrial fibrillation who are at a risk of developing coronary artery disease, which may necessitate PCI with stents [31]. Clopidogrel can be replaced with ticagrelor in rare cases [32, 33]. Cangrelor, a potent intravenous P2Y12 inhibitor with fast onset of action, can be indicated for treating unconscious ACS patients on emergency who are unable to absorb an oral P2Y12 inhibitor [34].

#### **3.3 Coronary artery disease**

DAPT with aspirin and clopidogrel is recommended for patients with CAD in order to avert atherothrombotic events. In patients undergoing elective stent implantation, DAPT with aspirin and clopidogrel is usually recommended for 3–6 months [30, 35].

#### **3.4 Myocardial infarction, ischemic events, and stroke**

In previous years, DAPT with aspirin and clopidogrel or ticagrelor was formerly recommended for preventing recurrent stroke especially in patients with high risk of transient ischemic attack and noncardioembolic mild stroke [36]. However, DAPT has been found in previous studies to reduce the incidence of stroke and CVS-related death, thus making it effective for stroke prevention. Because DAPT reduces the risk of minor stroke and high transient ischemic attack in these patients, DAPT can be recommended in combination with aspirin and a P2Y12 inhibitor for acute treatment of patients with acute noncardioembolic minor ischemic stroke [37].

Novel and trending studies have compared the efficacy of other potent P2Y12 antagonist such as ticagrelor and prasugrel with clopidogrel especially in preventing nonfatal MI, ischemic CVS events, stroke, and other CVS-related death [38]. DAPT with aspirin and clopidogrel is also approved for treating patients with severe stenosis of the intracranial artery [39] and chronic symptomatic peripheral artery diseases (PADs) [40].
