- Relevant clinical history and physical exam:
A 58 years old man with effort angina was admitted to our hospital for the PCI for CTO lesion. He received drug-eluting stent (Cypher 3.0 * 33mm) in distal LCX lesion due to STEMI at other hospital about 4 months ago. The target lesion was a CTO lesion in the proximal LAD. The distal LAD was well filled through the rich collateral channels via septal branch. His risk factor was only smoking. The creatinine value was 0.8 mg/dL (estimated GFR = 90).

- Relevant test results prior to catheterization:
The transthoracic echocardiography showed normal LV function (ejection fraction = 55%). Other non-invasive studies were not performed.

- Relevant catheterization findings:
The target lesion was a CTO lesion in the proximal LAD. The distal LAD was well filled through the rich collateral channels via septal branch. (Figure 1, Figure 2, Figure 3)

- Procedural step:
A 8Fr XB 3.5 guiding catheter was engaged in the left and a 5Fr JR-4.0 guiding catheter in the right coronary artery through the bi-femoral approach, respectively. At first, the antetrograde approach was attempted. Initially, a 0.014 inch Floppy guidewire was inserted into the Ramus intermediate (RI) branch and IVUS was performed. By the IVUS guiding, initially 0.014 inch Miracle 3g wire was advanced to the LAD occlusion site. (Figure 4) After failing the first guidewire passage, consequent approaches with Miracle 12g and 0.014 inch Conquest pro wire were performed. However these wires could not cross into the distal true channel. After failing anterograde approach, we decided to change the strategy to the retrograde approach and changed right guiding catheter to 7Fr JR-4.0 guiding catheter. Initially, the combination of an the Fielder FC guidewire and a Progreat