Mechanism of Stent Failure in Patients with Eruptive Calcified Nodule Treated with Rotational Atherectomy

Abstract

Background Percutaneous coronary intervention (PCI) for lesions with eruptive calcified nodules (CNs) is associated with worse outcomes compared with that for other calcified lesions. We aimed to clarify the relationship between eruptive CNs at index PCI, optical coherence tomography (OCT) findings at the 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 eruptive CNs (35 patients [38 lesions]). Results Post-PCI, stent expansion was comparable between the two groups, and CN-like protrusion was found in 75% of lesions with eruptive CNs. Follow-up OCT at 8 months revealed in-stent CNs in 54% of treated eruptive CN lesions, whereas lesions without eruptive CNs lacked in-stent CNs. Multivariate linear regression analysis demonstrated that eruptive CN was associated with maximum neointimal tissue (NIT) thickness (regression coefficient 0.303; 95% confidence interval: 0.057–0.549, p=0.02). Consequently, patients with eruptive CNs exhibited a higher clinically-driven target lesion revascularization (TLR) rate than did those without at 1 year (31.3% vs. 2.9%, p=0.009) and 5 years (43.8% vs. 11.4%, p=0.02). TLR primarily occurred in lesions with maximum eruptive CN arc angles>180°. Conclusions Following RA treatment with acceptable stent expansion, eruptive CNs before PCI correlated with greater NIT formation with in-stent CNs, resulting in a higher TLR rate, particularly in lesions with maximum eruptive CN arc angles exceeding 180°.