Abstract 2756: Carotid Plaque Inflammation On 18 F-Fluorodeoxyglucose Positron Emission Tomography Predicts Early Stroke Recurrence- The Dublin Carotid Atherosclerosis Stroke Study

Abstract

Background Symptomatic carotid stenosis is associated with a 3-fold risk of early stroke recurrence compared to other stroke subtypes. Current carotid imaging techniques rely on estimating plaque-related lumen narrowing but do not evaluate intra-plaque inflammation, a key mediator of plaque rupture and thromboembolism. Using combined 18 F-fluorodeoxyglucose positron emission tomography/CT (FDG-PET/CT) we investigated the relationship between inflammation-related FDG uptake and stroke recurrence. Methods Consecutive patients with a recent (median 6.5 days [IQR 4-8]) stroke, TIA, or retinal embolism and ipsilateral carotid stenosis ( ≥50%) were included. FDG uptake was quantified as mean standardised uptake values (SUV, g/ml). Patients were followed prospectively for stroke recurrence. Results 60 patients were included (25 stroke, 29 TIA, 6 retinal embolism). 22% (13/60) had stroke recurrence within 90 days. FDG uptake in ipsilateral carotid plaque was greater in patients with early recurrent stroke (mean SUV 1.85 [SD 0.44] vs. 1.58 [SD 0.32] g/ml, p=0.02). On life-table analysis, 90-day recurrence rates with mean SUV greater than a 2.14g/ml threshold were 80% (CI 41.8-99.2%) versus 22.9% (CI 12.3-40.3%) with SUV ≤2.14g/ml (log-rank p<0.0001). In a Cox regression model including age and degree of stenosis (50-69% or ≥70%), mean plaque FDG uptake was the only independent predictor of stroke recurrence (adjusted hazard ratio 6.1, CI 1.3-28.8, p=0.02). Conclusion In recently-symptomatic carotid stenosis, inflammation-related FDG uptake was associated with early stroke recurrence, independent of the degree of stenosis. Plaque FDG-PET may identify patients at highest risk for stroke recurrence, who may be selected for immediate revascularisation or intensive medical treatment.