Interventional Cardiology. Группа авторов

for treatment of severe resistant coronary lesions [28].

Microcatheters

      Microcatheters constitute over the wire support systems that contribute to the success of both antegrade and retrograde recanalization techniques. They were specifically developed to enhance lesion crossing and can substantially increase the support offered to the guidewire when they are engaged within the lesion. Microcatheters also allow reshaping or changing the guidewire without losing the distal position. They prevent prolapse of the guidewire and improve its penetration ability. Microcatheters can also straighten a tortuous artery proximal to the lesion and increase the guidewire torque. They can also be used to inject contrast dye to visualize the distal vessel. Due to their small profile, they can also cross the lesion when small balloons fail to do so. A wide range of microcatheters are currently available and they can be divided into different categories according to their characteristics:

       Large diameter microcatheters, such as the Corsair (Asahi Intecc, Nagoya, Japan), Turnpike and Turnpike Spiral (Teleflex, Wayne, PA, USA). Larger microcatheters are usually used to improve guidewire support during antegrade CTO crossing.

       Small diameter microcatheters, such as the Finecross (Terumo, Somerset, New Jersey), Caravel (AsahiIntecc), Turnpike LP (Teleflex), and Micro 14 (BTG, London, United Kingdom). Like the larger ones, they are used to increase guidewire support but, thanks to their smaller diameter, they are also particularly useful to negotiate tortuosity and cross severe lesions.

       Angulated microcatheters, such as the Supercross (Teleflex) and Venture (Teleflex), used to access side branches. Recently, the steerable microcatheter (SwiftNINJA, Sumitomo Bakelite, Tokyo, Japan), which has a remote controlled flexible tip manipulated using a dial in the handgrip, was developed, enabling the operator to change the angle of the microcatheter tip manually, and potentially makes selective catheterisation easier [29]

       Dual lumen microcatheters, such as the TwinPass and TwinPassTorque (Teleflex); Sasuke (Asahi), NHancer Rx (IMDS, The Netherlands). They consist of a rapid delivery system exchange in the distal segment associated with an OTW lumen along the catheter. Although each device has its own peculiar characteristics, all these devices share a common feature, that is the presence of two lumens, whose purpose is to allow precise and independent handling of two different guidewires. The rapid exchange distal port is at the distal end of the catheter, while the OTW lumen starts some mm more proximally and runs the whole length of the catheter. Two radiopaque markers are positioned in order to identify the exit ports of both lumens. The role of dual lumen microcatheters has been expanding [30,31] and they can be used for: parallel wire technique; antegrade wiring of CTOs with side branch at the proximal cap; wiring distal true lumen without losing access to a distal side branch near the distal cap; antegrade wiring of the distal true lumen if the externalized retrograde guidewire crossed a collateral close to the distal.

       Plaque modification microcatheters, such as the Tornus (Asahi Intecc), and Turnpike Gold (Teleflex): they are specifically designed for difficult crossing cases and may enlarge a channel through an uncrossable lesions after successful guidewire crossing. Tornus is advanced rotating counterclockwise, whereas the Turnpike Gold is advanced by rotating clockwise. Rotating in the opposite direction is needed for removal.

Conclusions

      A good operator will have a thorough knowledge of the advantages and limitations of each specific piece of equipment, familiarity with their specific characteristics and modalities of use, and a preparedness to change to an alternative strategy or strategies if required.

       Interactive multiple choice questions are available for this chapter on www.wiley.com/go/dangas/cardiology

      References

      1 1 Hamon M, Sabatier R, Zhao Q, et al. Mini‐invasive strategy in acute coronary syndromes: direct coronary stenting using 5 Fr guiding catheters and transradial approach. Catheter CardiovascInterv 2002; 55(3): 340–343.

      2 2 de Bruyne B, Stockbroeckx J, Demoor D, et al. Role of side holes in guide catheters: observations on coronary pressure and flow. Cathet Cardiovasc Diagn 1994; 33(2): 145–152.

      3 3 Pym J, Brown P, Pearson M, Parker J. Right Gastroepiploic‐to‐coronary artery bypass: the first decade of use. Circulation 1995; 92(9): 45–49.

      4 4 Isshiki T, Yamaguchi T, Nakamura M, et al. Postoperative angiographic evaluation of gastroepiploic artery grafts: technical considerations and short‐term patency. CathetCardiovascDiagn 1990; 21(4): 233–238.

      5 5 Alam M, Safi AM, Mandawat MK, et al. Successful percutaneous stenting of a right gastroepiploic coronary bypass graft using monorail delivery system: a case report. Catheter CardiovascInterv 2000; 49(2): 197–199.

      6 6 Colombo A, Mikhail GW, Michev I, et al. Treating chronic total occlusions using subintimal tracking and reentry: The STAR Technique. Catheter CardiovascInterv 2005; 64(4): 407–411.

      7 7 Jafary FH. When one won’t do it, use two—double ‘buddy’ wiring to facilitate stent advancement across a highly calcified artery. Catheter CardiovascInterv 2006; 67(5): 721–723.

      8 8 Hamood H, Makhoul N, Grenadir E, et al. Anchor wire technique improves device deliverability during PCI of CTOs and other complex subsets. Acute Cardiac Care 2006; 8(3): 139–142.

      9 9 Fujita S, Tamai H, Kyo E, et al. New technique for superior guiding catheter support during advancement of a balloon in coronary angioplasty: the anchor technique. Catheter CardiovascInterv 2003; 59(4): 482–488.

      10 10 Takahashi S, Saito S, Tanaka S, et al. New method to increase a backup support of a 6 French guiding coronary catheter. Catheter CardiovascInterv 2004; 63(4): 452–456.

      11 11 Mamas MA, Eichhöfer J, Hendry C, et al. Use of the Heartrail II catheter as a distal stent delivery device: an extended case series. EuroIntervention 2009; 5(2): 265–271.

      12 12 Hiwatashi A, Iwabuchi M, Yokoi H, et al. PCI using a 4‐Fr “child” guide catheter in a “mother” guide catheter: Kyushu KIWAMI® ST registry. CathetCardiovascIntervent 2010; 76(7): 919–923.

      13 13 Fraser DG, Mamas MA. Guide catheter extensions: where are they taking us? EuroIntervention 2012; 8(3): 299–301.

      14 14 de Man FHAF, Tandjung K, Hartmann M, et al. Usefulness and safety of the GuideLiner catheter to enhance intubation and support of guide catheters: insights from the TwenteGuideLiner registry. EuroIntervention 2012; 8(3):336–344.

      15 15 Chan PH, Alegria‐Barrero E, Foin N, et al. Extended use of the GuideLiner in complex coronary interventions. Eurointervention 2015; 11: 325–35

      16 16 Fabris E. et al.; Guide extension, unmissable tool in the armamentarium of modern interventional cardiology. A comprehensive review; Int J Cardiol. 2016 Nov 1; 222:141–147.

      17 17 Yamane M, Muto M, Matsubara T, et al. Contemporary retrograde approach for the recanalisation of coronary chronic total occlusion: on behalf of the Japanese Retrograde Summit Group. EuroIntervention 2013; 9(1): 102–109.

      18 18 Tsuchikane E, Yamane M, Mutoh M, et al. Japanese multicenter registry evaluating the retrograde approach for chronic coronary total occlusion. Cathet Cardiovasc Intervent 2013; 82(5): E654–661.

      19 19 Secco GG, Di Mario C. A new dedicated ultrashort steerable balloon for side branch ostial dilatation. Catheter Cardiovasc Interv. 2011; 77:363–6.

      20 20 Mauri L, Bonan R, Weiner BH, et al. Cutting balloon angioplasty for the prevention of restenosis: results of the Cutting Balloon Global Randomized Trial. Am J Cardiol. 2002; 90: 1079–1083.

      21 21 Sadamatsu K, Yoshida K, Yoshidomi Y, et al. Comparison of pre‐dilation with a non‐compliant balloon versus a dual wire scoring balloon for coronary stenting. World J Cardiovasc Dis 2013; 3:395–400.

      22 22 Jujo K, Saito K, Ishida I, et al. Intimal disruption affects drug‐eluting cobalt‐chromium stent expansion: a randomized trial comparing scoring