International Circulation: Could you share with us your experience of the radial approach intervention and what are some of the advantages and disadvantages of the radial approach?

Prof. Saito: Of course， the advantage of the transradial approach for chronic total occlusion is that the patient can walk， stand up immediately after the procedure. That is the significant advantage， especially for elderly patients. But， it has a lot of disadvantages for chronic total occlusion. Firstly， it is difficult to take a simultaneous bilateral angiography. From the femoral approach， we can easily make a double puncture.But， for the radial approach – of course， we could take the bi-radial approach， but I don’t think it a good choice for the patient. Secondly normally we use a 6 frame guiding catheter from the radial artery. Of course， in some patients we can use a 7 frame， even 8 frame， guiding catheters， but normally we use the 6 frame. By using 6 frame guiding catheters the back-up support is weaker than for the 7 or 8 frame guided catheters. The third reason we have is that because of the limitations of the size of the guiding catheters， some of the techniques which have been developed for the chronic total occlusion cannot be used. For example， ultrasound guiding technique – we cannot do it， so we have several disadvantages.

International Circulation: Obviously， there has been a lot of work of CTO in Japan - the CTO Club etcetera – what is the success rate for PCI with CTO in Japan?

Prof. Saito: Yes， that is a very difficult question to answer because of course it depends on which patients we have to include， but normally our success rate is above 90%.

International Circulation: Can you introduce the skill of using the guide wire crossing the entire CTO and reaching the distal true lumen?

Prof. Saito:First of all we have to make the adequate selection of guide wire. Nowadays we very often start with plastic jacket tapered hydrophic wires， especially if we think there are some micro-channels with the total occlusion. In other cases we normally start with a Miracle 3 equivalent guide wire. Then， if this wire cannot pass through， we directly step up to the Conquest Pro or Miracle 12， and we skip the middle strengths.

International Circulation: What are the complications that you frequently encounter and how do you handle them?

Prof. Saito: I think the most frequent complication we have is， of course， penetration by the guide wires， but normally the guide wire penetration is a kind of safe complication， because if we do not pass anything like a balloon， normally the bleeding will stop spontaneously， so even is we have guide wire penetration we continue the procedure. But the most serious complication is of course that sometimes we may have active bleeding from the artery and have to make a tamponade. So we almost always have to be ready for the pre-cardio synthesis. And， the other complication we may have is some distal embolization after the recanalization， but we cannot predict. However， normally the angioplastical CTO is a kind of safe procedure.

International Circulation: And how about the role of multi-slice CT in CTO， can you talk about that please?

Prof. Saito: Yes， that is helpful because by doing the CT angiography， we can identify whether there is a calification or not， so it’s very important to choose the correct guide wire. Also， especially for the ostial chronic total occlusions， by taking the CT， we may identify where the entry point is， and that is very important.

International Circulation: How about finding the true lumen by MSCT?

Prof. Saito: Of course， in the total occlusion part， the contrast cannot go in， but still we can identify it because we can see some black there， so we can identify where the entry point is – that is very important information， especially for the ostial.

International Circulation: Is there any research into new treatment of CTO that you have done and what are the advances that you see coming out recently or in the near future?

Prof. Saito: Above all， we are focusing on the refinement of the retrograde approach and also we are still trying to improve the guide wire. In addition， we may start randomized comparisons starting from the plastic jacket hydrophic wire or conventional wire for CTO. That is perhaps a new trend.