3. IVUS guide antegrade stump location and overcoming tough proximal cap

Antegrade stump ambiguity should be overcome with IVUS guide. The IVUS should be placed in the branch nearest to the antegrade stump and angiograms in multiple views taken to confirm stump location. In rare cases where there is antegrade stump ambiguity but no usable side branch near the stump for IVUS, retrograde wiring up to the proximal cap may help remove ambiguity safely.
If the proximal cap is tough and a side branch is available next to the proximal cap, a Twin lumen catheter (Crusade/Twinpass) should be placed onto the side branch wire to allow stronger back up force for wiring the proximal cap. A high penetration wire such as Conquest 12 g/Gaia 3rd should be used in these cases but once the high penetration wire punctures the proximal cap. After successful puncture of proximal cap, step down to a lower penetration power wire (e.g. XTA or Gaia 2nd) should be used.

Once the wire has made some progress into the proximal CTO, the Twin lumen catheter can be exchanged for a corsair to drill into the CTO to allow better wire support for the crossing of the CTO. If the twin lumen catheter with high penetration wire cannot puncture the proximal cap, side branch anchor balloon with a corsair supported high penetration wire can be tried. If this fails, a large OTW balloon can be used to anchor the corsair in the vessel proximal to the proximal cap to give strong back up force for high penetration wire to puncture the proximal cap. As a last resort, a high penetration wire can be used to puncture into the subintimal space of the vessel wall proximal to the CTO and a corsair tip can be placed into the subintimal space. Through this corsair, a knuckle wire can then be used to knuckle pass the tough proximal cap. Intentional Cross Boss and Stingray can be used after this to complete the wire crossing.