Читать книгу Interventional Cardiology - Группа авторов - Страница 135

By placing one guide catheter inside another, the advantages of the passive support provided by a large guide catheter are combined with the ability to actively engage the smaller catheter into the target vessel (Figure 5.5) [10]. Compatibility of different guide catheter lengths and diameter is a limiting factor. Mainly a 6 Fr, 110 cm long “child” guide catheter is combined within an 85 or 90 cm 7 or 8 Fr “mother” guide catheter. These limitations have been overcome by the use of dedicated longer and smaller coaxial catheters. The Heartrail II® “five‐in‐six catheter system” comprises a flexible‐tipped, long (120 cm) 5 Fr catheter advanced through a standard 6 Fr guiding catheter to deeply intubate the target vessel. This system uses the target vessel itself to provide the extra backup support required for stent delivery. Furthermore, the absence of a primary curve and the flexibility of its tip permit the “child” catheter to remain coaxial with the target vessel, thereby minimizing the risk of catheter‐induced coronary dissection. Use of this system has been shown to be useful in the treatment of CTO cases where such increased backup support is important. However, its use requires removal of the Y‐connector, making the procedure more demanding [11].

The Kiwami® 4 Fr‐in‐6 Fr catheter measures 120 cm, 1.43mm (outer diameter) 1.27mm (inner diameter); the inner layer is coated with polytetrafluoroethylene (PTFE) and the surface is coated with a hydrophilic surface up to 15 cm from the tip of the catheter. The backstream prevention valve (Terumo) is connected to the guide catheter of 6 or 7 Fr. The conventional Y‐connector is attached to Kiwami® (child) which was inserted in the 6 or 7 Fr (mother) catheter. Because the effective length of Kiwami® is 120 cm, the projected length from the mother catheter differs depending on the length of mother catheter used [12]. The 4 Fr‐in‐6 Fr Kiwami® catheter is probably the most deliverable among the GC extensions, but has the smallest lumen (0.050 inch) and requires meticulous attention to details to avoid air embolism [13].