Patients with acute coronary syndrome (ACS) require platelet inhibition after treatment. P2Y12 receptor blockage is a well-known, proved method of urgent and effective blockade of the platelet activation, and is applied to the current practice protocol. Ticagrelor is a well-performing P2Y12 receptor blocking agent which is used in these patients. In the same matter, it is essential to prescribe the exact dosage to optimize efficacy within the safety limits. However current studies are based on Western countries, whereas there has been no Ticagrelor patient registry in East-Asia. Thus it is reasonable to study the use of Ticagrelor in a large registry of Korean ACS patients.

The BK registry is a Prospective, Open-label, Multi-center, Real world, Registry, with prospective registration of patients receiving the medication, Ticagrelor. All subjects are to be followed up for 18 months after diagnosis and treatment for ACS.

The purpose of this study is to observe and register clinical data including Major Adverse Cardiovascular Endpoints and any total bleeding occurrence in Korean ACS patients treated with Ticagrelor during 18 month follow-up. Also, the purpose includes to determine compliance of Ticagrelor during post-approval commercial use and to determine prescription pattern of Ticagrelor during post-approval commercial use.

Inclusion Criteria:

1. Provision of informed consent prior to any study specific procedures. Alternatively, a legally authorized patient representative may agree to the patient's participation in this study and sign the informed consent form.
2. Patients who are taking ticagrelor and acetylsalicylic acid daily or Patients who are taking ticagrelor only according to label. All treatment modalities for Acute coronary syndrome (invasive and non-invasive) are allowed.

Exclusion Criteria:

• None

ACS pateints who use Brilinta as a anti-platelet agent