Patterns of Neoatherosclerotic Plaque Complications in Patients With Stent Failure: An Optical Coherence Tomography Study

BACKGROUND: Neoatherosclerosis is a major mechanism of late and very late stent failure. While plaque rupture (PR) has traditionally been considered the dominant substrate, the prevalence and characteristics of other neoatherosclerotic plaque complications remain insufficiently defined. We aimed to investigate the morphological and clinical differences between neoatherosclerotic PR and plaque erosion (PE) using optical coherence tomography (OCT). METHODS: This retrospective single-center study included patients with stent failure undergoing OCT-guided percutaneous coronary intervention between January 2020 and December 2025. Patients with neoatherosclerosis-related stent failure were classified according to OCT findings as PR or PE. Clinical presentation, angiographic characteristics, OCT-derived plaque morphology, and long-term outcomes were compared. RESULTS: Among 103 screened patients, 44 met the inclusion criteria; 28 had PR, 14 had PE and 2 had instent eruptive calcific nodule. PR patients more frequently presented with STEMI and demonstrated significantly higher levels of macrophage infiltration (57.1% vs. 23.1%, p = 0.043), cholesterol crystals (60.7% vs. 28.6%, p = 0.050), lipid arc ≥ 180° (80% vs. 42.9%, p = 0.031), and thin-cap fibroatheroma (35.7% vs. 7.1%, p = 0.048). In contrast, layered plaque was markedly more prevalent in PE (92.9% vs. 48.3%, p = 0.004), and minimal in-stent lumen area was smaller in PE lesions (p = 0.039). Postprocedural thrombus protrusion was significantly more common in PR (81% vs. 27.5%, p = 0.005). Although not statistically significant, all-cause and cardiac mortality were numerically higher in PR patients during follow-up. CONCLUSIONS: Neoatherosclerotic PR and PE represent distinct mechanisms of stent failure with different inflammatory profiles, plaque morphology, and clinical presentations. PR is associated with higher lipid burden and inflammatory activity, whereas PE is characterized by layered neointima and lower inflammatory features. OCT-based plaque characterization may improve risk stratification and support personalized treatment strategies in late stent failure.