Side branch preservation using tip detection-antegrade dissection re-entry after failed subintimal tracking and re-entry in chronic total occlusion: a case report.

Background: Techniques for treating difficult chronic total occlusions (CTOs) have evolved with the discovery of the tip detection-antegrade dissection re-entry (TDADR) guided by intravascular ultrasound (IVUS). This case demonstrates TDADR as a viable bailout in failed subintimal tracking and re-entry (STAR) technique. Case summary: A 78-year-old man with stable angina on optimal medical therapy had exertional angina pectoris secondary to a residual CTO lesion of the left circumflex coronary (LCX) artery. Percutaneous coronary intervention was performed for a mid-LCX CTO with a blunt proximal stump where the dissection plane expanded along the main vessel and side branch 2. Due to lack of promising collaterals for the retrograde approach, STAR successfully recanalized side branch 1. As main vessel failed to be recanalized, we proceeded with an AnteOwl IVUS-guided TDADR, intending guidewire penetration into the true lumen from the middle of the dissection plane at the main vessel, proximal to side branch 2 origin. Accurate wiring was achieved, and a guidewire was placed on side branch 2 for protection. After stent placement in the main vessel and kissing inflation, cutting balloon dilatation was performed to create re-entries for the STAR-induced extended main vessel haematoma. The procedure resulted in complete revascularization of main vessel and side branches. At 12-month follow-up, no further angina was reported, and coronary computed tomography showed patent side branches with no significant in-stent restenosis. Discussion: Imaging-based TDADR method was effective in our present case despite failed STAR technique. Limited IVUS and operator availability may become a barrier in implementing TDADR.