Coronary chronic total occlusion (CTO) is a very common disease, clinically it takes up about one-third of patients receiving cardiac catheterization treatment. In the past 20 years, CTO lesions represent the most difficult challenge of the cardiac catheterization treatment, as it is a highly complex lesion with only a very low success rate in treatment. The latest development is a retrograde approach surgery, which becomes a very important method in the percutaneous CTO treatment, able to improve the success rate by about 20%. The conventional anterograde surgery often uses a sharp and hard wire to puncture the CTO, its success or failure mostly depends on the surgeon hand feeling, whereas in the aspect of retrograde surgery, it is first to select the most appropriate collateral circulation and then use a super-smooth wire plus a microcatheter, if they both can smoothly pass to the remote end of CTO, then subsequent practice includes the following technologies: direct crossing, kissing wire technique, CART and reverse CART. Currently, there are two strategies after successful direct crossing or reverse CART (1) externalization: which is, after the retrograde wire and microcatheter are advanced into the antegrade guiding catheter, a 300cm wire is used to pass through the anterograde wire from the retrograde direction, and complete the subsequent procedure in an anterograde manner. This practice was published in 2009, and is used by most CTO surgery nowadays. (2) rendezvous is another method was published by Dr. Kazuaki Mitsufuji in 2007. After the retrograde wire and microcatheter are advanced into the antegrade guiding catheter, another anterograde microcatheter and retrograde microcatheter are used at the maximal bending location of the antegrade guiding catheter to enable a wire to enter retrograde microcatheter from the anterograde microcatheter. However, most of the operators consider it too difficult. In response to this shortcoming, a new catheter is disclose
