Different LD of Ticagrelor for Antiplatelet Effect in Patients With Non-ST-segment Elevation ACS Undergoing PCI

Inclusion Criteria: * Provision of informed consent prior to any study specific procedures. * Male or non-pregnant female; aged from 18 to 80 years old. * Patients with non-ST-segment elevation acute coronary syndromes who were scheduled to undergoing PCI. Exclusion Criteria: * Any contraindication against the use of ticagrelor. * On treatment with a P2Y12 receptor antagonist in past 30 days. * Known allergies to aspirin or ticagrelor. * On treatment with oral anticoagulant (Vitamin K antagonists, dabigatran, rivaroxaban). * Known blood dyscrasia or bleeding diathesis. * ST-segment elevation acute myocardial infarction. * Non-ST segment elevation acute coronary syndrome with high-risk features warranting emergency coronary angiography. * Left ventricular ejection fraction ≤30%; renal failure with creatinine 3 mg/dl; history of liver disease; an increased risk of bradycardia, and concomitant therapy with drugs interfering with CYP3A4 metabolism.