Abstract 20739: Compared to C-Reactive Protein and Homocysteine, [18F]-FDG PET/CTA Uptake is Directly Related to Intraplaque Inflammatory Burden of High-Risk Carotid Plaque: A Sub-Study of the Canadian Atherosclerosis Imaging Network (CAIN-2)
Background: Inflammation may contribute to plaque instability. C-reactive protein (CRP) and total homocysteine (tHcy) are considered to be putative risk factors for cardiovascular disease. It is suggested that CRP and tHcy are associated with plaque inflammatory activity, although this relationship has not been established. [18F]-fluorodeoxyglucose (FDG) uptake imaged with positron emission tomography (PET) and computed tomography (CT) may also serve as a biomarker of plaque inflammation. The aim of the current investigation was to determine whether FDG, CRP and tHcy are directly related to intraplaque inflammatory burden, as defined by the extent of macrophage-specific CD68 immunohistology.
Methods: Fifty-eight patients (67±9 years, 17 female) scheduled for carotid endarterectomy were prospectively recruited for FDG PET/CT imaging the internal carotid arteries. tHcy and CRP were available for 44 and 52 patients, respectively. Maximum FDG uptake normalized to blood (tissue to blood ratio - TBR) was measured for carotid plaque. Following carotid endarterectomy, excised plaque was immunostained for macrophage-specific CD68 immunohistology and whole-slide digitized images were used to quantify CD68 expression.
Results: Maximum carotid FDG uptake correlated with the extent of intraplaque CD68 expression (r=0.53, p<0.0001). There was no relationship between the extent of carotid CD68 expression and serum levels of CRP (r=-0.1, p=0.53), nor tHcy (r=0.06, p=0.70).
Conclusion: FDG uptake in high-risk carotid plaque is directly related to the extent of intraplaque inflammation. C-reactive protein and homocysteine may not be robust markers of carotid plaque instability, as defined by inflammatory activity.
Author Disclosures: M.S. Cocker: None. J. Spence: None. R.R. Hammond: None. R.A. deKemp: None. C. Lum: None. A. Hill: None. S. Nagpal: None. G. Stotts: None. L. Garrard: None. J.N. DaSilva: None. J. Tardif: None. R. Beanlands: None.
- © 2016 by American Heart Association, Inc.