Arterial inflammation measured by 18F-FDG-PET-CT to predict coronary events in older subjects

Abstract

Background and aims: Although ¹⁸F-fluorodeoxyglucose (FDG) uptake has emerged as a sensitive and reliable marker of atherosclerotic inflammation, its additive predictive value for future coronary disease in older subjects is unknown. The aim of this study was to test the prognostic value of aortic inflammation detected via FDG-positron emission tomography (PET)-computed tomography (CT) in older subjects.

Methods: We retrospectively utilized the records of 309 subjects aged over 65 years, without a history of coronary artery disease, who underwent ¹⁸F-FDG-PET-CT mostly due to the clinical suspicion of cancer, but eventually turned out to be cancer-free. Target-to-background ratio (TBR) was calculated at the ascending aorta. The endpoint was occurrence of coronary heart disease (CHD) events.

Results: During a median follow-up of 3.9 years, 28 subjects experienced CHD events and 12 patients died due to non-CHD causes. The highest TBR tertile was associated with a high CHD event rate, accounting for death due to non-CHD causes as a competing risk (Gray test, p = 0.005). In a Fine and Gray competing risk proportional hazard regression model, TBR was associated with significantly high CHD events independently of FRS, with a hazard ratio (HR) of 1.19 per 0.1 TBR increase (p < 0.001). Likewise, a significant increase in the area under the curve (from 0.57 to 0.73, p = 0.028) and a significant improvement in net reclassification (0.42, p = 0.038) were observed when TBR was added to the model with FRS alone.

Conclusions: In older subjects with no history of malignant disease or overt coronary artery disease, arterial inflammation evaluated by FDG uptake provides information on future occurrence of coronary artery events.

Keywords: Coronary heart disease event; Framingham risk score; Prognosis.