A patient with prior CABG was referred for PCI of a RCA CTO with clear tapered proximal cap, long occlusion length, bifurcation at the distal cap, with the distal vessel filling via an epicardial collateral from the OM that was in turn filling via a saphenous vein graft. Antegrade wiring failed. Retrograde wiring through the epicardial collateral succeeded using a Caravel microcatheter and Suoh 03 guidewire. Retrograde advancement of a Gladius Mongo failed. We exchanged the Caravel for a Corsair microcatheter but during attempts to advance the microcatheter the retrograde guide position was lost. The AL1 guide engaging the SVG-OM1 was exchanged for an AL2 guide that provided stronger support. A guide extension was also used. A knuckled retrograde Gladius Mongo was advanced to the RCA ostium. Antegrade wiring attempts failed. The antegrade guide was changed from an AL1 to an AL2 and using the BASE technique an antegrade Gladius Mongo was advanced extraplaque in the proximal RCA. Reverse CART was successful but the retrograde microcatheter could not be advanced to the antegrade guide extension. The antegrade guide extension was inchwormed to the mid RCA over the retrograde microcatheter, followed by externalization of an R350 guidewire. A nice final result was achieved after stenting. An antegrade microcatheter was advanced into the epicardial collateral. Contrast injection in the collateral did not show any injury/perforation.
