PARTICULARITIES OF CALCIFICATION OF THE HEART VALVULAR APPARATUS IN PATIENTS SUBJECT TO KIDNEY-REPLACEMENT THERAPY WITH PROGRAMMED HEMODIALYSIS

Abstract

SUMMARY. Studying of characteristics of cardiac valve calcification (CVC) as a manifestation of chronic kidney disease – mineral and bone disorder (CKD-MBD) is a highly relevant issue in clinical practice among patients with CKD stage V, as this condition is associated with increased cardiovascular morbidity and mortality in this patient population.

The aim – to identify risk factors for CVC in patients with CKD stage V through the analysis of key clinical and laboratory parameters.

Material and Methods. A single-center, cross-sectional cohort study was conducted at the hemodialysis department of the Ternopil Regional Clinical Hospital, within which 134 patients with CKD stage V were examined. In all patients, levels of vitamin D, C-reactive protein (CRP), lipid profile, urea, creatinine, total protein, and albumin , ferritin, ESR, intact parathyroid hormone (iPTH), calcium (Ca), phosphorus (P), alkaline phosphatase activity (ALP), and glycated hemoglobin (HbA1c) levels were measured. All patients performed two-dimensional echocardiography and X-rays of the spine and extremities. Circulating sclerostin (SCL) levels were determined using the automated sandwich ELISA SOST for humans with SimpleStep technology (ab221836) from Abcam (Cambridge, UK).

Results. CVC was detected in 48.5 % of the study participants, whose mean age was 59.32±11.7 years; 34 (52.3 %) were men and 31 (47.7 %) were women. According to the study results, patients with CVC differed significantly in age (59.32±11.17 vs. 51.42±14.14; p=0.002); in the number of patients with diabetes mellitus – there were significantly more such patients in the CVC group (16/24.6 % vs. 8/11.6 %; p=0.009); in terms of duration of hemodialysis treatment – patients with CVC were on hemodialysis significantly longer (58.00 vs. 29.00; p=0.003). In the group of patients with CVC, serum P levels were significantly higher (1.99 vs. 1.65; p=0.003), which was associated with lower Ca levels (2.06 vs. 2.26; p=0.027); significantly higher levels of circulating SCL (760.04 vs. 448.52; p=0.021); significantly higher levels of CRP (12.08 vs. 8.19; p=0.044). In addition, patients with CVC had a significantly higher incidence of low-energy fractures (vertebral and non-vertebral) (21/32.3 % vs. 6/8.7 %; p=0.001).

Conclusions. CVC, as a manifestation of CKD-MBD, is a common finding in patients with CKD stage V. Its development is primarily associated with age, the duration of renal replacement therapy with programmed hemodialysis, and diabetes mellitus. The laboratory basis for CVC is a severe mineral metabolism disorders in the form of hyperphosphatemia and hypocalcemia against a background of vitamin D deficiency in the context of chronic inflammation. Clinically, CVC is associated with an increased incidence of vertebral and non-vertebral fractures in patients with CKD stage V, which supports the concept of the bone-vascular axis. In addition, CVC is associated with a significant increase in circulating sclerostin levels, which is a modern marker of CKD-MBD in patients with CKD stage V.