Acute Stent Thrombosis Following Reprotrusion of a Calcified Nodule in the Left Main Coronary Artery

Calcified nodule (CN) is a high-risk phenotype of coronary artery calcification that causes in-stent restenosis frequently. Stent thrombosis (ST) is a critical complication following percutaneous coronary intervention, and its onset is associated with severely calcified lesions. However, the association between CN and ST remains unclear. Moreover, while reprotrusion of CNs through the stent strut is not uncommon immediately after stenting, the risk of ST associated with this acute reprotrusion of CNs is not well recognized. We present a case of a 70-year-old female who developed acute ST following reprotrusion of a CN in the left main coronary artery. After the successful stenting to a large CN, a prominent acute protrusion occurred, followed by the acute occlusion of the implanted stent due to massive thrombus formation. This case highlights the importance of careful monitoring for thrombus formation even after good stent expansion, especially when large acute reprotrusion of CNs is observed.