Clinical Impact of Calcified Nodules in Patients with Severely Calcified Lesions Treated by Rotational Atherectomy: A Serial Optical Coherence Tomography Study

ABSTRACT Background Percutaneous coronary intervention (PCI) for lesions with calcified nodules (CNs) is associated with worse outcomes than PCI for other calcified lesions. We aimed to clarify the relationship between CNs at index PCI, optical coherence tomography (OCT) findings at 8-month follow-up, and clinical outcomes using serial OCT. Methods This retrospective observational study utilized data from a prospective, single-center registry. We conducted consecutive PCI for calcified lesions requiring rotational atherectomy (RA) with OCT guidance. We categorized 51 patients (54 lesions) into those with (16 patients [16 lesions]) and without CNs (35 patients [38 lesions]). Results Post-PCI, stent expansion was comparable between the two groups, and CN-like protrusion was observed in 75% of patients in the CN group. Follow-up OCT at 8 months revealed in-stent CNs in 54% of treated CN lesions with CN-like protrusion, whereas non-CN lesions lacked in-stent CNs. The CN group exhibited greater maximum neointimal tissue (NIT) thickness than the non-CN group (p<0.001). Multivariate linear regression analysis demonstrated that CN was associated with maximum NIT (p=0.02). Consequently, the CN group exhibited a higher clinically-driven target lesion revascularization (TLR) rate than the non-CN group at 1 (p=0.009) and 5 years (p=0.02). TLR primarily occurred in lesions with maximum CN angles >180°. Conclusions Following RA treatment with acceptable stent expansion, the presence of CNs before PCI correlated with greater neointimal tissue formation with in-stent CNs, resulting in a higher TLR rate, especially in lesions with maximum CN angles exceeding 180°. What is Known Calcified lesions with calcified nodules (CNs) are associated with a higher target lesion revascularization (TLR) rate in percutaneous coronary intervention (PCI) than other types of calcified lesions. In-stent CNs may appear after PCI for CNs and is a major cause of increased TLR rates after PCI for CNs. The relationship between calcified plaque morphology at the index PCI, neointimal tissue characteristics concerning in-stent CN location and frequency during follow-up, and subsequent clinical outcomes has not been explored with serial optical coherence tomography. What the Study Adds Follow-up OCT at 8 months revealed in-stent CNs in 54% of treated CN lesions with CN-like protrusion, whereas non-CN lesions lacked in-stent CNs. PCI for CNs exhibited a higher clinically-driven target lesion revascularization rate than PCI for lesions without CNs, primarily in lesions with maximum CN angles >180°.