Antiplatelet has been the cornerstones management in acute coronary syndrome. However, numbers of patients on these agents had episodes of adverse cardiovascular events. A 65-year-old woman underwent cardiac coronary bypass surgery and discharge on dual antiplatelet therapy (DAPT) aspirin and clopidogrel. Four months later, she was readmitted due to acute chest pain and coronary angiography showed subtotal stenosis in proximal and distal anastomosis of saphenous vein graft. Patient was managed with intravenous anticoagulant together with DAPT and showed good clinical improvement. One month later, she developed another episode of typical angina and underwent balloon angioplasty. Symptom reduced after intervention and patient continue to receive DAPT. Despite patient’s good adhered to daily antiplatelet regimen, one year later she developed another episode of acute chest pain and drug eluting stent was placed on saphenous vein graft. Two months later, patient was readmitted due to chest discomfort and she was anxious of having another episode of acute coronary syndrome. Repetitive episodes of thrombotic events in this patient had led to clinical suspicious of antiplatelet resistance. Platelet function test was performed, which showed a raised level of P2Y12 reaction unit (PRU) of 267, indicates a poor platelet response to clopidogrel. While platelet function test for aspirin demonstrate good aspirin response. Clopidogrel was discontinued and ticaglelor was prescribed together with aspirin. During two months of follow up, no episode of chest discomfort was reported.