ABSTRACT NUMBER: ESOC2026A537 RISK FACTOR PROFILES FOR MEDIAL VS. INTIMAL INTRACRANIAL ARTERIAL CALCIFICATION DETERMINED ON A CT VISUAL SCALE IN PATIENTS WITH STROKE/TIA: A POPULATION-BASED VALIDATION STUDY

Abstract Background and aims CT-visualised intracranial arterial calcification (CT-IAC) is associated with stroke and dementia, but medial (arterial media) and intimal (mainly plaque) calcification represent distinct pathophysiological entities. We aimed to validate an existing visual scale for distinguishing medial from intimal CT-IAC against renal impairment and other candidate risk factors. Methods In patients with stroke/TIA from a UK population-based study, location (medial/intimal) and severity of CT-IAC was assessed using visual scales in both internal carotid arteries. Patients were grouped into medial, intimal, or mixed CT-IAC subtypes (Table 1). Multivariable logistic regression determined whether intimal CT-IAC was primarily related to risk factors for atherosclerosis (male sex and hyperlipidaemia) and medial CT-IAC to renal dysfunction. Results Among 731 patients (mean age=75.2±11.4 years), 207 (28.3%) had medial CT-IAC and 362 (49.5%) intimal CT-IAC. Risk factors for severe medial CT-IAC were age (adjusted OR=1.09,1.06-1.12,p<0.001), female sex (1.99,1.32-3.00,p=0.001), non-cerebral arterial disease (2.16,1.38-3.38,p=0.001), and renal function (SCr – aOR/30μmol/L=1.24,1.04-1.47,p=0.016; CKD stage – aOR/stage=1.56,1.08-2.26,p=0.017). Risk factors for severe intimal CT-IAC were age (1.06,1.01-1.11,p=0.010), hyperlipidaemia (2.24,1.00-5.00,p=0.049), and male sex (aOR for ≥moderate CT-IAC=1.59,1.16-2.29,p=0.005). Mediation analysis indicated that approximately 61.5% of the effect of CKD stage≥4 on overall CT-IAC severity was mediated through medial CT-IAC (Figure 1). Conclusions Compared with intimal CT-IAC, medial CT-IAC is more strongly associated with renal impairment, female sex, and non-cerebral arterial disease, whereas intimal CT-IAC is more strongly associated with hyperlipidaemia and male sex. The CT visual scale may be useful for distinguishing CT-IAC subtypes in aetiologic and prognostic studies. Conflict of interest Dr Ke (Michael) Li is supported by the Clarendon and COSF Funds. Prof Rothwell and the Oxford Vascular Study are supported by grants from the Wellcome Trust and the NIHR Biomedical Research Centre, Oxford. Table 1 - belongs to Conclusions Figure 1 - belongs to Conclusions