- Relevant catheterization findings:
The target lesion was a CTO lesion in the proximal RCA. The distal RCA was well filled through the rich collateral channels of the left anterior descending artery via the septal perforators.(Figure 2, Figure 3)

- Procedural step:
A 8Fr EBU-3.5SH-90CM and a SL1.0-SH guiding catheter (Launcher®) were engaged in the left and a 7Fr JR -4.0 guiding catheter in the right coronary artery through the bi-femoral approach, respectively. At first, the retrograde approach was attempted. We planned reverse-CART technique. We attempted to use least contrast amount due to LV dysfunction and renal function impairement.

By using the combination of an Fielder FC 0.014 inch guide-wire and a Finecross® 0.014 inch 1.8 Fr -130cm microcatheter, the arterial lumen distal to the CTO lesion was successfully reached through the septal branch via the left anterior descending artery.(Figure 4) By exchanging the system to a combination of X-treme guide-wire and Channel catheter 0.015 inch 2.6 Fr-130cm (Coronary Micro-Guide catheter), penetration the occlusion was attempted.(Figure 5) However, the occluded segment was so hard that retrograde wire at the distal entry point of the CTO lesion was not unsatisfactory. So, antegrade approach with Fielder FC 0.014 inchi guide-wire and Ryujin 1.5 *15mm OTW balloon was attempted. Successful crossing by a stiff guidewire into the subintimal space parallel to the true lumen proximal to the CTO lesion was achieved. (Figure 6) At this point, the reverse-CART technique was performed and a Ryujin® 2.5-mm OTW balloon was introduced antegradely. The balloon was inflated in the proximal part of the CTO lesion to create a large false lumen, which was connected with the true lumen proximal to the CTO lesion. (Figure 7) Following this balloon inflation, the retrograde guidewire (X-treme) was easily passed into the subintimal space to then reach the proximal true lumen. Retrograde wire was inserted into right guiding catheter lumen and then channel catheter was inserted into right guiding catheter. (Figure 8, Figure 9) The 0.014 inch – 300 cm Fielder wire was inserted from left guiding catheter to right guiding catheter forming wire loop (retrograde wire externalization). From the guide-wire tip outside of right sheath, predilation with Ryujin 2.5 * 15mm balloon was performed. (Figure 10) After IVUS examination, we deployed three drug-eluting stents (Xience-V 3.0 * 28 mm at proximal RCA, Xience-V 2.5 *28mm and Taxus-liberte 2.75 * 38 mm in distal RCA, sequentially). (Figure 11) Final angiogram showed successful revascularization at RCA CTO lesion. We used only 250 cc amount of contrast (Visipaque).