Asymmetric dimethylarginine as a useful risk marker of radial artery calcification in patients with advanced kidney disease.

INTRODUCTION    Medial arterial calcification is common in patients with chronic kidney disease (CKD) and is considered a risk factor for morbidity and mortality. OBJECTIVES    We aimed to evaluate the correlation between asymmetric dimethylarginine (ADMA) levels, radial artery calcification, and common carotid artery intima-media thickness (CCA‑IMT). PATIENTS AND METHODS    The study included 51 patients with CKD, in whom an arteriovenous fistula for hemodialysis access was created to collect radial artery samples for a histological examination, and 33 healthy volunteers, in whom the reference concentrations of ADMA were assessed. The concentrations of creatinine, albumin, calcium, phosphate, fibroblast growth factor 23, osteoprotegerin (OPG), osteopontin (OPN), osteocalcin, secreted protein acidic and rich in cysteine, interleukin 6, interleukin 18, pentraxin 3, stromal cell‑derived factor 1α (SDF1α), thrombomodulin, soluble tumor necrosis factor receptor II (sTNFRII), and matrix metalloproteinase 2 (MMP‑2) were determined. Radial artery fragments were stained for calcifications using alizarin red. The CCA‑IMT was assessed by ultrasonography. RESULTS    Patients with CKD had higher ADMA levels than controls. Patients with ADMA levels above the median were older, had higher levels of phosphate, fibroblast growth factor 23, OPG, OPN, PTX3, sTNFRII, MMP‑2, thrombomodulin, and they had more atherosclerotic plaques in the carotid artery. In multiple regression, log‑transformed (log)sTNFRII, MMP‑2, and SDF1α levels were independent predictors of log(ADMA). Patients with calcifications had higher ADMA levels. A similar correlation was observed between SDF1α and alizarin red staining grades 1 to 3. In logistic regression, ADMA levels positively predicted the presence of calcifications independently of age, hemodialysis status, Framingham risk score, and PTX3. CONCLUSIONS    Circulating ADMA levels indicate medial arterial calcification in patients with CKD.