Progression of Medial Arterial Calcification in CKD

INTRODUCTION: Medial arterial calcification is common in chronic kidney disease (CKD) and portends poor clinical outcomes, but its progression relative to the severity of CKD and the role of other risk factors is unknown because of the lack of reliable quantification. METHODS: Calcification of breast arteries detected by mammography, which is exclusively medial and correlates with medial calcification in peripheral arteries and with cardiovascular outcomes, was used to measure the progression of medial arterial calcification in women with CKD and end-stage renal disease (ESRD). Measurements showed intra- and interobserver correlations of 0.98, an interstudy variability of 8% to 11%, and a correlation with computed tomographic measurements of 0.92. RESULTS: Progression of calcification was measured in 60 control subjects (estimated glomerular filtration rate (eGFR) ≥ 90 ml/min per 1.73 m(2)) and 137 subjects with CKD (eGFR < 90 ml/min per 1.73 m(2)). Progression in control subjects was linear over time and independent of age. The rate of progression was increased in CKD but only at eGFR < 40 ml/min per 1.73 m(2) (median, 8.1 vs. 3.9 mm/breast/yr in controls; P = 0.006). Progression accelerated markedly in subjects with ESRD (median, 20 mm/breast/yr; n = 36), but did not differ from controls after kidney transplantation (n = 25). Diabetes significantly augmented progression in subjects with CKD and ESRD but not in controls. CONCLUSION: Mammography is a convenient and reliable method to measure the progression of medial arterial calcification. Progression does not increase until advanced stages of CKD, accelerates markedly in ESRD, and returns to control rates after kidney transplantation. Diabetes significantly increases progression in CKD and ESRD.