Media Calcification and Intima Calcification Are Distinct Entities in Chronic Kidney Disease

Abstract

Calcification of the vascular tree is common in physiologic and pathologic conditions, i.e., aging, diabetes, dyslipidemia, genetic diseases, and diseases with disturbances of calcium metabolism. In chronic kidney disease, vascular calcification is even more common, develops early, and contributes to the markedly increased cardiovascular risk in this particular population. Pathomorphologically, atherosclerosis (i.e., plaque-forming degenerative changes of the aorta and of large elastic arteries) and arteriosclerosis (i.e., concentric media thickening of muscular arteries) can be distinguished. Increasing knowledge about calcification together with improved imaging techniques provided evidence that also vascular calcification has to be divided into two distinct entities according to the specific sites of calcification within the vascular wall: Patchy calcification of the intima in the vicinity of lipid or cholesterol deposits as present in plaque calcification and calcification of the media in the absence of such lipid or cholesterol deposits, known as Mö nckeberg-type atherosclerosis. The two types of calcification may vary according to the type of vessel (large elastic versus smaller muscular type artery) and proximal versus distal sites of the arterial tree. Furthermore, clinical studies showed that it is not purely academic to distinguish between intimal and medial calcification but rather relevant for the clinical presentation, treatment, and prognosis because each type leads to different clinical consequences. In vivo studies in animal models provided evidence in favor of common pathomechanisms between vascular calcification and atherosclerosis; however, there is other, strong experimental and clinical evidence that pleads for the continued distinction between intimal and medial calcification.

Progression of Coronary Artery Calcification and Thoracic Aorta Calcification in Kidney Transplant Recipients

“…Vascular calcification may involve either the intima, in association with inflammation and atherosclerosis, or the media, causing vascular stiffness. Both processes often coexist in advanced CKD and cannot be distinguished by imaging techniques, including computed tomography (CT) (6). Still, vascular calcification strongly predicts CVD and all-cause mortality not only in hemodialysis and peritoneal dialysis patients (7-9) but also in RTR (10)(11)(12).…”

Breast Arterial Calcification

“…Calcification in the medial layer is independent of atherosclerosis or inflammation, occurs in small arteries in addition to large arteries, and is thought to be detrimental by decreasing arterial compliance (8). It is observed specifically in renal failure, diabetes, and aging (9), but its pathophysiology and natural history are otherwise poorly understood.…”

Acute tumoral calcinosis due to severe hyperphosphatemia in a maintenance hemodialysis patient

“…However, nutritional counseling helped the patient to improve his dietary habits after the occurrence of tumoral calcinosis and reduced his phosphate levels to 3-4 mg/dL. CKD-MBD is associated with two types of ectopic calcification [6]. Alpha-klotho is a co-receptor of fibroblast growth factor 23 (FGF23), which is involved in phosphate and calcium homeostasis [7].…”