A Pilot Trial to Examine the Effect of High-Dose Niacin on Arterial Wall Inflammation Using Fluorodeoxyglucose Positron Emission Tomography

Rationale and Objectives Although studies have reported direct inhibition of inflammatory pathways with niacin, the effect of niacin on arterial wall inflammation remains unknown. We examined the effect of niacin on arterial18 F-fluorodeoxyglucose (FDG)–positron emission tomography (PET)/computed tomography (CT). Materials and Methods Nine statin-treated patients with coronary disease were randomized to niacin 6000 mg/day or placebo. FDG-PET/CT and lipids were assessed at baseline and at 12 weeks. FDG was quantified in the aorta, right carotid artery, and left carotid artery as the target-to-background ratio (TBR) and target-to-background difference (TBD). Results Eight patients completed the study. No significant changes in FDG measured by aortic, left carotid, or right carotid TBR or TBD were seen in either group. Compared to baseline, niacin-treated subjects exhibited a significant 29% reduction in low-density lipoprotein cholesterol (LDL-C; 95% confidence interval [CI], −50% to 8%; P = .01) and a nonsignificant 29% reduction in LDL particle number (LDL-P; 95% CI, −58% to 0.2%; P = .07). A nonsignificant 11% increase in HDL-C (95% CI, −15% to 37%; P = .30) and 8% decrease in HDL-P (95% CI, −44% to 28%; P = .51) were observed with niacin treatment. In a pooled analysis, changes in LDL-P were positively correlated with FDG uptake in the aorta (TBR r = 0.66, P = .08; TBD r = 0.75, P = .03), left carotid (TBR r = 0.65, P = .08; TBD r = 0.74, P = .03), and right carotid (TBR r = 0.54, P = .17; TBD r = 0.61, P = .11). Conclusions In this pilot study, adding niacin to statin therapy did not affect arterial wall inflammation measured by FDG-PET/CT. However, an association between changes in arterial FDG uptake and LDL-P was observed. Larger studies are needed to definitively examine the effect of niacin on arterial wall inflammation.