Unfolding the Hidden: Indirect Culotte Stenting in a Parallel Left Anterior Descending Artery System for Chronic Total Occlusion – A Challenging Percutaneous Coronary Intervention

Chronic total occlusion (CTO) is a technically challenging lesion, and coronary variants such as a parallel left anterior descending (LAD) artery can obscure the target vessel. Parallel LAD is a rare congenital variant that can complicate interpretation when coexisting with CTO. Herein, the case of a 54-year-old woman who underwent percutaneous coronary intervention in November 2022 for a presumed LAD and presented with exertional angina is reported. Repeat angiography in January 2024 revealed an untreated proximal CTO of the true LAD. The previously treated vessel was reclassified as a large first diagonal branch representing the parallel LAD, whereas the vessel previously interpreted as a septal branch was identified as the true LAD. Antegrade wire escalation enabled CTO crossing followed by stent implantation in an indirect culotte configuration with kissing balloon inflation and proximal optimization. Final angiography demonstrated thrombolysis in myocardial infarction grade III flow in both vessels without complications.