Evaluation of Effectiveness and Safety of Antegrade and Retrograde Approach of Percutaneous Coronary Intervention for Chronic Total Occlusions

Inclusion criteria

• Patients aged>=19
• Patients who have a CTO lesion in at least one or more epicardial coronary artery 2.5 mm in blood vessel diameter
• Patients who have symptoms of angina or objectively proven myocardial ischemia (asymptomatic myocardial ischemia, stable or unstable angina, non - -ST-segment elevation myocardial infarction)
• Patients who voluntarily agreed to the protocol and the clinical follow-up plan (or let their representative do this), and signed the informed consent form approved by the IRB of each study institute

Exclusion criteria

• Patients who are pregnant or lactating or have childbearing potential Patients in whom contrast medium and heparin are contraindicated or who are hypersensitive to them
• Patients in whom aspirin, clopidogrel, ticagrelor and prasugrel, cilostazol are contraindicated
• Patients scheduled to undergo a surgery, etc. that requires discontinuance of an antiplatelet drug within 12 months after participation in the study
• Acute ST elevation myocardial infarction at the time of hospitalization
• Terminally ill patients with their life expectancy < one year
• Patients who have serious diseases other than cardiac diseases that may affect limitation of residual life time or observation of the protocol (e.g. oxygen-independent chronic obstructive pulmonary disease, persisting hepatitis or serious hepatic insufficiency, severe renal disease, etc. Be left up to the discretion of the investigator.)