Optimal Duration of Dual Antiplatelet Therapy After Stent-assisted Coiling

Inclusion Criteria: * subjects over 19 years old * subjects with modified Rankin Scale (mRS) ≤ 2 * subjects with unruptured intracranial aneurysms * subjects with appropriated aspirin and clopidogrel reaction units after dual antiplatelet preparation (100 mg of aspirin and 75 mg of clopidogrel) for at least 5 days before procedure \[measured using VerifyNow\] 1. aspirin reaction unit (ARU) \< 550 2. P2Y12 reaction unit (PRU): 85\~219 * subjects who agreed to this study (with informed consent) Exclusion Criteria: * subjects with neurological deficits (mRS ≥ 3) * subjects with an allergic reaction to antiplatelets (aspirin and clopidogrel) or contrast * subjects with a high risk of hemorrhage such ICH or severe gastric ulceration * subjects with coagulopathy * subjects with thrombocytopenia (\<100,000/mm3) * subjects with liver diseases (\> 100IU/L of aspartate aminotransferase or alanine aminotransferase) * subjects with renal diseases (\> 2mg/dL of serum creatinine) * subjects with underlying diseases that need to maintain dual antiplatelet drugs or anticoagulants. * subjects with a high risk of strokes (atrial fibrillation, over 70% cerebral artery stenosis or cerebral artery occlusion, moyamoya disease, vascular malformations, etc) * subjects with uncontrolled congestive heart failure or angina * subjects with malignant tumors * subjects with a positive pregnancy test (serum or urine) * subjects who are unconscious at the time of diagnosis. * subjects who are unable to complete the required follow-ups * subjects with life-threatening diseases * subjects with medical conditions with a life expectancy of less than two years * subjects who are determined to be disqualified by researchers