ABSTRACT NUMBER: ESOC2026A145 RESIDUAL CALCIUM DENSITY REFLECTS PLAQUE VULNERABILITY AND CEREBROVASCULAR EVENT RISK IN SYMPTOMATIC CAROTID ARTERY DISEASE

Abstract Background and aims Carotid calcification features are readily quantifiable by CTA, yet their relationship with plaque vulnerability and rupture remains controversial. We investigated whether calcium score, volume, density, and residual (volume-normalized) calcium density are associated with carotid plaque vulnerability, symptomatic status, and recurrent ipsilateral ischemic stroke and transient ischemic attack (TIA). Methods Patients with recent TIA or ischemic stroke and ≥2mm carotid plaque with <70% stenosis underwent baseline CTA and MRI. Carotid calcifications were segmented on CTA (≥130 Hounsfield units), yielding calcium score, volume, and density. Volume-normalized residual calcium density was calculated as the standardized residuals from a log-transformed calcium density-volume model (Figure 1). Vulnerable plaque features (intraplaque hemorrhage, thin-or-ruptured fibrous cap, and lipid-rich necrotic core, and ulceration) were linked to calcium metrics. Associations between calcium metrics and recurrent ipsilateral TIA or ischemic stroke were assessed using Cox regression and adjusted for age, sex, stenosis. Results Among 193 patients (mean age 67.8±8.5 years, 144 (75%) men), 26 experienced ipsilateral ischemic stroke or TIA over median 5-year follow-up. Lower calcium density and residual calcium density were independently associated with vulnerable plaques (adjusted ORs: 0.40-0.60; Figure 2). Residual calcium density remained independently associated with symptomatic side (adjusted OR: 0.64, 95%CI: 0.47-0.88) and with recurrent TIA/stroke (adjusted HR: 0.53, 95%CI: 0.29-0.95). Calcium score, volume, and density were not independently associated with symptomatic side or recurrent events (Figure 3). Conclusions Residual calcium density is a robust, independent marker of carotid plaque vulnerability and ipsilateral ischemic stroke and TIA risk in patients with symptomatic carotid artery disease. Conflict of interest Juul Bierens: nothing to disclose; Daniel Bos: nothing to disclose; Paul J. Nederkoorn: nothing to disclose; Pim A. de Jong: nothing to disclose; Robert J. van Oostenbrugge: nothing to disclose; Luc J.M. Smits: nothing to disclose; Jae W. Song: nothing to disclose; Giuseppe Lanzino: nothing to disclose; M. Eline Kooi: nothing to disclose; Luca Saba: nothing to disclose. Figure 1 - belongs to Methods Figure 2 - belongs to Results Figure 3 - belongs to Conclusions