Carotid FDG Uptake Improves Prediction of Future Cardiovascular Events in Asymptomatic Individuals

Abstract

ObjectivesThis study sought to investigate the role of carotid fluoro-2-deoxyglucose (FDG) uptake as an independent prognostic indicator and to determine whether its addition improves risk prediction beyond the Framingham risk score (FRS) and carotid intima-media thickness (CIMT). BackgroundThe prognostic value of carotid FDG uptake independent of and incremental to traditional cardiovascular risk factors and CIMT in asymptomatic individuals has not been evaluated. MethodsWe measured carotid FDG uptake and CIMT in 1,089 asymptomatic adults (51.8 ± 6.3 years of age, 94.3% males) who underwent positron emission tomography/computed tomography imaging and examined the prognostic value of carotid FDG uptake compared with traditional risk factors and CIMT. ResultsCardiocerebrovascular events occurred in 19 participants (1.74%) during an average follow-up of 4.2 years (range 1.0 to 5.5 years). Multivariable Cox proportional hazards analyses revealed that high carotid FDG uptake (hazard ratio: 2.98; 95% confidence interval: 1.17 to 7.62; p = 0.022) and high CIMT (hazard ratio: 2.82; 95% confidence interval: 1.13 to 7.03; p = 0.026) were independent predictors of events. Comparison of predictive power demonstrated that adding carotid FDG uptake, but not CIMT, to the FRS significantly increased the time-dependent area under the receiver-operating characteristic curve from 0.60 to 0.73 (p = 0.04). Furthermore, improvement approaching significance was achieved by adding carotid FDG uptake to the FRS plus CIMT, which increased the area under the receiver-operating characteristic curve from 0.65 to 0.75 (p = 0.07). Net reclassification for event prediction was similarly improved by addition of carotid FDG uptake to the FRS (net reclassification index, 40.1%; p = 0.06), as well as the FRS plus CIMT (net reclassification index, 32.9%; p = 0.07). ConclusionsHigh carotid FDG uptake predicts cardiovascular events independent of traditional risk factors and CIMT in asymptomatic adults and may add to risk stratification beyond the FRS and CIMT.