"Tip-In" technique for retrograde chronic total occlusion revascularization

Use of the retrograde approach significantly improves the success rate of chronic total occlusion (CTO) percutaneous coronary intervention. The most commonly applied retrograde technique is placing a guidewire just distal to the distal cap using collateral vessels, with subsequent retrograde crossing of the occlusive segment. This is followed by advancement of a microcatheter and externalization of a long guidewire to allow antegrade delivery of balloons and stents. However, there are occasions when a microcatheter or balloon cannot be delivered retrogradely through the occlusive segment, resulting in procedure failure. We describe the "tip-in" technique, which involves intubation of the retrograde guidewire with an antegrade microcatheter to allow successful revascularization of a CTO after failure to externalize.