In patients with stable ischemic heart disease undergoing percutaneous coronary intervention (PCI), the transradial approach is recommended to reduce access site bleeding and vascular complications. The transradial approach facilitates an earlier time to ambulation and lower rates of vascular and bleeding complications, and it is especially effective in patients who take anticoagulation drugs or are severely obese. The abnormal vessel route from the radial to the ascending aorta is an impediment to guiding catheter insertion and stabilization. PCI operators may have difficulty passing devices such as small balloons and microcatheters even after successful wire crossing through the true lumen. This is one of the major reasons for technical failure of transradial intervention for chronic total occlusion (CTO). The advantages of the transradial approach may be offset by the disadvantages regarding guiding back-up support and available devices/strategies in the treatment of complex CTO.