Abstract 19815: Staging Atherosclerotic Disease and Vessel Remodeling with [18F]-Sodium Fluoride, a Novel Biomarker of Active Calcification: Sub-study of the Canadian Atherosclerosis Imaging Network (CAIN-2)
Background: [18F]-sodium fluoride (NaF) positron emission tomography (PET) uptake may serve as a marker of active calcification. Osteopontin regulates active calcification within plaque. Positive vessel remodeling is a marker of vulnerable plaque.
We hypothesized that active calcification within carotid plaque, as determined by NaF PET/CT uptake, is associated with osteopontin expression and positive vessel remodeling.
Methods: Eleven patients (69±5 years, 3 females) scheduled for carotid endarterectomy were prospectively recruited for NaF PET/CT imaging of the carotids. The bifurcation of the common carotid was used as the reference point; maximum NaF uptake normalized to blood (tissue to blood ratio - TBR) was measured at every PET slice extending 2 cm above and below the bifurcation.
Using NASCET criteria, cross-sectional vessel area was measured and related to proximal and distal segments, generating a vessel remodeling index (RI) for every PET slice. Regions with a RI ≤ 1.0 were classified as positive remodeling.
Excised plaque was immunostained for osteopontin and whole-slide digitized images were used to quantify osteopontin expression. Pathology was co-registered with PET.
Results: Immunohistology was available for 8 plaques. As a result of intraplaque clustering, a meta-analysis was performed and demonstrated that NaF uptake was related to intraplaque osteopontin expression (r=0.37, p=0.03) (Figure 1). NaF uptake was greater in regions with positive vessel remodeling (TBR=2.6±0.9 with positive (n=185) vs. 1.6±0.6 (n=46) without positive remodeling, p<0.001).
Conclusion: Atherosclerosis is a progressive disease. Along this continuum, we have found that there is inter-plaque variability in calcific activity and NaF uptake correlated with osteopontin expression. NaF uptake is directly related to vessel remodeling. Thus, NaF is a novel biomarker of active calcification and may serve as a tool to stage atherosclerosis.
Author Disclosures: M.S. Cocker: None. J. Spence: None. G. Wells: None. R. Hammond: None. B. McArdle: None. R. deKemp: None. C. Lum: None. T. Karavardanyan: None. A. Adeeko: None. A. Hill: None. S. Nagpal: None. G. Stotts: None. C. Kelly: None. J. Brennan: None. L. Garrard: None. M. Alturkustani: None. L. Hammond: None. J. DaSilva: None. M. Yaffe: None. J. Tardif: None. R. Beanlands: None.
- © 2014 by American Heart Association, Inc.