The purpose of this study is to show that the radiation exposure of the left distal radial artery approach is superior to the conventional right radial artery approach in terms of less radiation exposure.

The conventional radial approach is now recognized as the basic technique in coronary artery surgery. Compared to the femoral artery access, the main advantage is the increased stability due to the reduction of massive bleeding. Due to these advantages, recent guidelines recommend the conventional radial approach as the basic approach for all acute myocardial infarction (AMI) cases with or without ST-segment elevation. In particular, in the case of ST-segment elevation myocardial infarction (STEMI), new antiplatelet agents such as Ticagrelor and Prasugrel and strong antiplatelet agents such as Glycoprotein inhibitors have been used to prevent major vascular complications. For these many operators, primary percutaneous coronary intervention (PCI) through the radial artery is recommended. At this time, the operator prefers the right radial artery approach because of the comfort of performing the procedure on the patient's right side. However, the operator sometimes has to substitute the left radial artery or femoral artery access due to difficulty in manipulating the catheter due to severe tortuousness of the right subclavian artery. Although the left radial artery approach requires less operation time and radiographic imaging time due to less tortuousness of the left subclavian artery, the right conventional radial approach is still preferred due to the ergonomic inconvenience of having to lean toward the patient. Patients undergoing coronary angiography (CAG) were randomly assigned to the left snuffbox approach and the right conventional radial approach, and the surgeons' radiation exposure between the two approaches was evaluated and compared.

Inclusion Criteria:

1. Patients aged 20 years or older
2. Patients scheduled for coronary angiography and intervention

Exclusion Criteria:

1. When the pulse of the Left distal radial artery cannot be palpated
2. When the pulse of the right conventional radial artery cannot be palpated
3. In case of arteriovenous fistula
4. Acute myocardial infarction (AMI) patients
5. In case femoral artery access must be performed (state of shock, etc.)
6. In case of atrioventricular block
7. When an ergonovine provocation test is required
8. When the patient refuses to consent to the study
9. a pregnant or nursing woman