**3. Vascular calcification in chronic kidney disease**

Cardiovascular disease is the leading cause of death in patients with CKD, especially among those with end stage renal disease (ESRD) [76, 77]. This high cardiovascular risk may be in part due to excess VC [78, 79].

The prevalence of vascular calcification in CKD patients increases with progressively decreasing kidney function and is greater than the general population [21, 80]. In patients with estimated glomerular filtration rate (eGFR) less than 60 mL/ min/1.73 m2 and not on dialysis, VC is known to be present in 47 to 83%. In dialysis adult patients, coronary artery calcification (CAC) has been detected in 51–93% and valvular calcification in 20–47% [2, 5, 81].

Increased CV risk may be due to CAC, with remarkably high prevalence in patients undergoing dialysis [8, 76, 82, 83]. It can be said that 20-year-old patients in dialysis have the same CV mortality risk as 80–90 year-old non-diabetic and non-uraemic subjects [82]. This may be associated with dialysis vintage, the intake of supplemental calcium, particularly with calcium-containing phosphate binders, and the mean calcium-phosphorus ion product.

#### **3.1 Clinical significance**

The diagnosis of CKD–Mineral Bone Disease (MBD) includes the detection of extra-osseous calcification, such as arterial, valvular, and myocardial calcification [5].

The clinical significance of vascular calcification depends on the site (ie, medial or intimal) and type of the affected arteries. Intimal calcification is associated with the formation and progression of atherosclerotic lesions and is associated with the development of plaques and occlusive lesions as in coronary artery disease, cerebrovascular disease, and peripheral vascular disease [9].

Tunica media calcification was initially considered to be clinically nonsignificant [9]. However, it was later demonstrated in CKD and ESRD patients that was associated with decreased vascular distensibility and increased vessel stiffness and pulse pressure with consequent progression of intimal lesions [9, 11, 84–86]. London et al. conducted a study including 202 HD patients which showed that medial calcification had major impact on clinical outcome, being an independent prognostic marker for all cause and CV mortality in chronic HD patients independently of classical atherogenic factors, with close association to time on HD [8].

#### *3.1.1 Coronary artery calcification*

Coronary artery calcification (CAC) is common and progressive in young adults with ESRD who are undergoing dialysis [21]. Some studies reveal an association between CAC and CVD in this population [80, 83].

Coronary artery calcification score, measured noninvasively by electron-beam computed tomography (EBCT), was found to be an independent predictor of overall *Vascular Calcification and Cardiovascular Risk in Chronic Kidney Disease: A Problem That Is… DOI: http://dx.doi.org/10.5772/intechopen.99886*

mortality in dialysis patients [87]. In one study with 39 patients undergoing HD, those with CAC had higher serum phosphorus concentrations, higher calcium–phosphorus ion product in serum, and their daily intake of calcium-containing phosphatebinding agents was nearly two times greater than those without calcification [21].
