**Author details**

coronary circulation, and within the microcatheter, a 330-cm long special externalization wire can be advanced from retrogradely and outside of the body (so-called "externalization"). After wire externalization, balloon dilation and stent implantation will then be performed

Most CTO lesions can be recanalized by antegrade techniques. In about 30%, a retrograde technique is necessary due to the complex morphology of the CTO (**Figure 5**). An escalation of the recanalization strategy is valuable, because an antegrade attempt may be successful in the case of a complex morphology of the CTO. Retrograde methods reveal a high technical expertise and should only be performed independently by interventional cardiologists with sufficient training in antegrade techniques (i.e., >300 antegrade CTO-interventions, >50/year) and additional training in retrograde techniques (25 retrograde cases as second and primary operator each), as stated in a consensus document of the EuroCTO-club [9]. In the presence of high expertise in all recanalization techniques, availability of necessary specific materials and a possible widened indication up to 90% of CTOs can be recanalized. However, the high

• Retrograde passage of

• Kissing wires (marker wire)

on

on

collaterals

p" – wires • Contralateral injec-

**Escalating strategy for recanalization**

**Antegrade Retrograde**

**Figure 5.** Escalating strategies for recanalization (CART, controlled antegrade and retrograde tracking).

• Reverse CART • Externaliza-

• Tip-in, rendez-vous

antegradely using the externalization wire.

• "Tapered -

• Microcatheters

• Parallel wire technique

**6. Recanalization strategies**

92 Interventional Cardiology

Michael Behnes1 \* and Kambis Mashayekhi2

\*Address all correspondence to: michael.behnes@umm.de

1 First Department of Medicine, University Medical Centre Mannheim (UMM), Faculty of Medicine Mannheim, University of Heidelberg, Mannheim, Germany

2 Division of Cardiology and Angiology II, University Heart Center Freiburg Bad Krozingen, Bad Krozingen, Germany
