导丝体外化技术
逆向导丝通过CTO病变到达近端血管真腔后，继续将导丝与微导管进入正向指引导管。可以通过以下2种方法完成导丝轨道建立技术。
1.RG3体外化专用导丝 通过逆向指引导管—微导管—正向指引导管途径送入RG3导丝至正向指引出口，最后退出微导管，建立正向轨道。体外化导丝能提供足够的支撑力，但是会增加供体血管缺血时间。
2.穿微导管技术 当逆向微导管到达正向指引导管时，送至正向指引导管转弯部位，而正向导丝前端塑形的弯度不呈半圆形，此时，旋转正向导丝，操作幅度可稍大，即可穿入逆向微导管（图17—0—11）。逆向微导管简单易行，能提高逆向PCI效率，减少供体血管缺血时间，但对开口异常的血管支撑力差。因此正向导丝进入微导管后，尽量送远导丝，甚至到达对侧的指引导管，以增加支撑力。
此外，有些情况下，如当逆向微导管无法到达正向指引导管时，也可采用反穿微导管技术，即在正向指引导管内送入正向微导管（通常使用Finecross微导管），并在正向指引导管转弯部位操作逆向导丝穿入正向微导管。(https://www.daowen.com)
逆向介入治疗CTO病变时，常常需要转换或同时使用多种方案，根据术者的经验与病变的情况及时调整。随着术者经验的积累、手术专用器械的更新，逆向CTO技术的开展愈发有效。侧支导丝探查技术、内膜下寻径技术等均需要特殊技巧与学习过程，所幸的是逆向技术的成功开展是可复制的。基于“ESC理念”等标准化介入流程，希望能提高手术效率与安全性，减少使用多种器械造成浪费，同时能降低手术治疗门槛，提高CTO介入治疗手术成功率。
图17—0—11 穿微导管技术
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