Calcifications, Arterial Stiffness and Atherosclerosis

Vascular calcification can occur in either the intimal or medial layers of the arterial wall. Intimal calcification is associated with athero sclerosis, which is characterized by lipid accumulation, inflammation, fibrosis and development of focal plaques. Medial calcification is associated with arterio sclerosis, i.e. age- and metabolic disease-related structural changes in the arterial wall which are related to increased arterial stiffness. It has been hypothesized that vascular calcification, either intimal or medial, may directly increase arterial stiffness. Alternatively, arterial stiffness may contribute to the development of calcification and focal plaque. Ample evidence (i.e. animal data and studies of diabetes and end-stage renal disease) has demonstrated that medial calcification of elastic fibers contributes to increased arterial stiffness. Evidence linking intimal calcification with arterial stiffness is less definitive, partly because it is very difficult to differentiate vascular calcification due to focal plaques (intimal) from medial calcification, and partly because the number of studies has been small. Conclusion: Current evidence supports that medial calcification is associated with increases in arterial stiffness. The association between intimal (atherosclerotic-associated) calcification and arterial stiffness is less definitive.