Cardiovascular Calcification in Chronic Hemodialysis Patients: Contributors Interplay

Abstract

Traditional cardiovascular risk factors are common among chronic kidney disease (CKD) patients. However the high prevalence of atherosclerosis and arterial calcification in CKD is far beyond the explanation by common cardiovascular risk factors. The aim of this study is to determine the incidence of cardiovascular calcification and its relation to demographic data, hemodialysis data and laboratory biomarkers and to evaluate the cardiovascular risk of atherosclerosis in hemodialysis patients. Fourty CKD patients on regular hemodialysis and twenty healthy volunteers were subjected to echocardiography, carotid ultrasound and laboratory studies including serum parathrmone (PTH), 25(OH) vitamin D, feutin and osteoprotegerin levels (OPG). The echocardiographic data showed a statistically significant increase in interventricular septum thickness (IVST), posterior wall thickness (PWT) and left ventricular mass index (LVMI) in patients group compared to the controls. Thirty patients (75%) had valvular calcification. There was significant increase in carotid intima-media thickness (CIMT) in patients group. Serum levels of Ph, PTH and Osteoprotegerin were significantly increased, however, serum levels of Ca, Vitamin D and Feutin were significantly decreased in patients group. Serum level of Ph, and Osteoprotogerin were significantly increased while Vitamin D and feutin were significantly decreased in patients with valvular calcification compared to patients without valvular calcifications. The level of Vitamin D and Fetuin were negatively correlated with creatinine, PTH and osteoprotogerin. While, the level of osteoprotogerin and PTH were positively correlated with creatinine and with each other, they were negatively correlated with HDL-c and eGFR. CIMT was positively correlated with LVMI, PWT, urea, creatinine, CRP, Ca and was negatively correlated with EF%, eGFR, HDL-c, vitamin D and Feutin. We concluded that hemodialysis patients with valvular calcifications were older in age, with a longer hemodialysis duration and showed higher Ph level, Ca x P product and OPG level and lower 25(OH)-vitamin D and fetuin A level. Also, they showed lower EF % and were on lower doses of alphacalcidol and higher doses of calcium compared to patients without valvular calcifications. So, our study points to the importance of administration of active vitamin D derivatives to decrease the risk of valvular calcification and atherosclerosis. Serum fetuin A and osteoprotegerin can be used as a simple, easily performed biomarkers mirroring valvular calcification in hemodialysis patients. Further studies should be done to assess trials for the addition of fetuin A in the treatment of CKD patients to prevent the occurrence of calcification.