Impact of CYP2C19 Genotype-guided Approach in Antiplatelet Therapy on Platelet Reactivity Index Among Coronary Artery Disease (CAD) Patients

Inclusion Criteria: * Males or females * Aged between 18 to 80 years old * Patients presents with stable CAD or acute coronary syndrome (ACS) * Eligible for percutaneous coronary intervention (PCI) * Willing to provide DNA sample via blood drawn for genotyping and platelet reactivity assessment * Willing and able to provide informed written consent Exclusion Criteria: * Primary PCI or rescue PCI * Any urgent/emergent coronary angiography procedure that would not allow for genetic testing to be performed before PCI * Failure of index PCI * Patient or physician refusal to enroll in the study * Patient with known CYP2C19 genotype prior to randomization * Planned revascularization of any vessel within 30 days post-index procedure and/or of the target vessel(s) within 12 months post-procedure * Anticipated discontinuation of clopidogrel or ticagrelor within the 12 months follow up period (e.g. for elective surgery) * History of ischaemic or haemorrhagic stroke * History of allergies to aspirin, ticagrelor, or clopidogrel * Suffering from HIV or any blood transmitted disease. * Considered at high risk of bleeding\* * Stage 5 chronic kidney disease (CKD) based on the National Kidney Foundation, Kidney disease quality outcome initiative (KDQOI) definition (Levey et al., 2005), or those who were on haemodialysis * Pre-existing liver cirrhosis * Pregnant women at any stage of gestation * Patient is receiving immunosuppressive therapy or has known immunosuppressive or autoimmune dise…