Peripheral artery calcifications evaluated by histology correlate to those detected by CT: relationships with fetuin-A and FGF-23

Background: Calcification of arteries is a frequent occurrence in hemodialysis (HD) patients and is linked to mortality. This study was conducted to evaluate the correspondence between coronary calcification scores and calcifications observed histologically in peripheral arteries in HD patients. In addition the association of humoral parameters including fetuin-A and fibroblast growth factor 23 (FGF-23) with arterial calcifications was studied. Patients and methods: HD patients (n=44) were studied with multislice computed tomography (CT) and histological quantification of arterial calcifications in the lower epigastric artery sampled at the time of renal transplant. In addition, humoral assays were performed including fetuin-A and FGF-23. Results: There was a significant correlation between medial calcification of the artery and Agatston scores. Natural logarithm (Ln) FGF-23 significantly correlated to Ln Agatston score but not to Ln medial calcification. A significant negative correlation between fetuin-A and Ln FGF-23 was observed, changing to borderline significance after correction for age and Ln HD age. Ln Agatston score in a multiregression analysis was predicted by Ln FGF-23 and age. Conclusions: The association found between histologically evaluated calcification of the media of a peripheral artery in HD and the multislice CT Agatston scores is in favor of a generalized arterial calcification, either intimal or of tunica media, when calcium deposits are found in the coronary arteries. The association of FGF-23 with coronary calcification score, already reported, and less so with histological medial calcification is in favor of a link between the protein and intimal more than the medial calcification. FGF-23 may be considered a potential biomarker of arterial calcification in HD patients. The negative association between fetuin-A and FGF-23 may suggest a linkage between these humoral substances, vascular calcifications and mortality. The nature of this linkage requires further studies.