The Impact of Selected Factors on the Cardiovascular System in Chronic Kidney Disease

the complete blood count was analyzed using Sysmex K-4500 Automated Hematology Analyzer (by GMI Inc., USA): * hemoglobin (HGB) \[g/dl\]; * red blood count (RBC) \[10\^12/l\]; * hematocrit (HCT) \[l/l\]; * white blood cells (WBC) \[10\^9/l\]; * platelet count (PLT) \[10\^9/l\]

body mass index (BMI) \[kg/m\^2\] was calculated by dividing a person's weight (post-HD weight in HD group) \[kg\] by the squared their body height \[m\]

Serum concentration of: * advanced glycation ends products (AGE) \[µg/mg protein\]; * 3-nitrotyrosine (3-NT) \[µmol/mg protein\]; * advanced oxidation protein products (AOPP) \[µmol/mg protein\]; * carboxymethyle(lysine) (CML) \[µg/mg protein\] were determined with the enzyme immunoassay methods (ELISA) using Shanghai Sunred Biological Technology Co kits, China.

metalloproteinases in the serum \[ng/ml\]: * metalloproteinase 9 (MMP-9) in the serum was determined by the ELISA method using the Quantikine Human MMP-9 (total) kit, by R&D Systems, Canada; * tissue inhibitor of metalloproteinase 1 (TIMP-1) in the serum - was determined by the ELISA method using the Quantikine Human TIMP-1 kit, manufactured by R&D Systems, Canada; * the MMP-9/TIMP-1 ratio was calculated by the quotient of the MMP-9 and the TIMP-1 concentration.

* total cholesterol (T-C) \[mg/dl\] - was assessed by routine techniques using Cobas Integra 400 plus biochemical analyzer by Roche Diagnostics, USA; * low-density lipoprotein cholesterol (LDL-C) \[mg/dl\] - was assessed by routine techniques using Cobas Integra 400 plus biochemical analyzer by Roche Diagnostics, USA; * high-density lipoprotein cholesterol (HDL-C) \[mg/dl\] - was assessed by routine techniques using Cobas Integra 400 plus biochemical analyzer by Roche Diagnostics, USA; * triglycerides (TG) \[mg/dl\] - were assessed by routine techniques using Cobas Integra 400 plus biochemical analyzer by Roche Diagnostics, USA; * the concentration of low-density lipoprotein (LDL-C) cholesterol - was determined from Friedewalds' equation (LDL-C \[mg/dl\] = total cholesterol (T-C) \[mg/dl\]- HDL-C \[mg/dl\]- TG\[mg/dl\]/5).

* iron concentration \[mg/dl\] - was analyzed with the Cobas Integra 400 plus biochemical analyzer from Roche Diagnostics, USA; * total iron-binding capacity (TIBC) \[mg/dl\] - was analyzed with the Cobas Integra 400 plus biochemical analyzer from Roche Diagnostics, USA; * the unsaturated iron-binding capacity (UIBC) \[mg/dl\] was determined by an equation in which iron concentration in plasma is subtracted from TIBC \[mg/dl\]; * ferritin \[ng/ml\] concentration was determined with the Modular E-170 biochemical analyzer from Roche Diagnostics, USA.

* high-sensitivity C-reactive protein (hsCRP) \[mg/l\] was measured using DADE Behring, USA and the DADE nephelometer Behring Analyzer II; * neopterin \[nmol/l\] was determined by using the Neopterin ELISA kit, DRG International, Inc., USA; * interleukin 18 (IL-18) \[pg/ml\] concentration was determined by Colorimetric Sandwich ELISA, Quantikine Human IL-18 R&D Inc., USA.

carotid intima-media thickness (IMT) \[mm\] was measured by The Accuson CV 70 system (Siemens) with a 10 megahertz (Mhz) transducer. Two longitudinal projections were assessed (anterolateral and posterolateral). The distal 1 cm of the common carotid artery just proximal to the bulb was measured by means of a computer analysis system (Medical Imaging Applications, LLC).

For non-invasive cardiological examinations, the Portapres device (Finapres Medical Systems (FMS), the Netherlands), the SphygmoCor tonometer (AtCor Medical), the Colin blood pressure monitor (BMP)-7000 (Japan) were used. Main assessed variables: heart rate (HR) \[beats per minute \[bpm\]\]; ejection duration (ED) \[millisecons\]; peripheral systolic (pSBP) and diastolic blood pressure (pDBP) \[mm Hg\]; peripheral mean arterial pressure (pMAP) \[mm Hg\]; peripheral end-systolic pressure (pESP) \[mm Hg\]; central systolic (cSBP) and diastolic blood pressure (cDBP) \[mm Hg\]; central mean arterial pressure (cMAP) \[mm Hg\]; central augmented pressure (cAP) \[mmHg\]; central mean pressure of diastole (cMPD)\[mm Hg\]; central mean pressure of systole (cMPS) \[mm Hg\]; central end-systolic pressure (cESP) \[mm Hg\].

The following parameters of vessel stiffness were assessed by Pulse Trace 2000 (Micro Medical Ltd., Rochester, Kent, United Kingdom): * reflection index (RI) \[in percentages \[%\]\]; * vascular stiffness index (SI) \[m/s\]; * peripheral pulse pressure (pPP) \[mm Hg\]; * central puls pressure (cPP) \[mm Hg\] * peripheral pulse pressure/central pulse pressure (pPP/cPP ratio).

During a 2-year follow-up from the enrollment to this study, CV-related fatal incidents history has been recorded for each subject separately. The primary endpoint was fatal acute myocardial infarction (AMI) or acute ischemic stroke or any unexpected or sudden death only if autopsy proved CV-related. If there was doubt about the cause of death or there was no contact with the patient during the two years from study enrollment, that patient was excluded and not considered further.

glucose (Glu) \[mg/dl\] was assessed in the serum by a routine technique using Cobas Integra 400 plus biochemical analyzer by Roche Diagnostics, USA.

klotho \[ng/ml\] - was analyzed in the serum by Human KL(Klotho) \[ng/ml\] ELISA Kit, Shanghai Sunred Biological Technology Co kit, China.

FGF-23 \[pg/ml\] - was analyzed in rhe serum using Human FGF-23 ELISA Kit, Sigma-Aldrich, USA.

* total and ionized calcium \[mg/dl\], * phosphate \[mg/dl\], * intact parathormone (iPTH) \[mg/dl\] were assessed by routine techniques using Cobas Integra 400 plus biochemical analyzer by Roche Diagnostics, USA.

activity of: * alanine transaminase (ALT) \[U/l\]; * aspartate transaminase (AST) \[U/l\]; * alkaline phosphatase (ALP) \[U/l\] were assessed by routine techniques using Cobas Integra 400 plus biochemical analyzer by Roche Diagnostics, USA.

* total protein (TP) \[g/dl\]; * albumin (ALB) \[g/dl\] were assessed in the serum by routine techniques using Cobas Integra 400 plus biochemical analyzer by Roche Diagnostics, USA.

* creatinine in the serum \[mg/dl\] - the assay is based on the reaction of creatinine with sodium picrate as described by Jaffe (Jaffes' colorimetric method) - was assessed by routine techniques using Cobas Integra 400 plus biochemical analyzer by Roche Diagnostics, USA; * urea \[mg/dl\] in the serum - was assessed by routine techniques using Cobas Integra 400 plus biochemical analyzer by Roche Diagnostics, USA.

myeloperoxidase (MPO) \[ng/ml\] in the serum- was determined by the ELISA method using the Quantikine Human MPO test by R&D Systems kit, Canada.

soluble receptor for advanced glycation end products (sRAGE) \[µg/mg protein\] in the serum was tested with enzymatic immunoassay (Quantikine ELISA) using R&D Systems kit, Canada.

* methylglyoxal (MG) \[µg/mg protein\]; * carboxyethyle(lysine) (CEL) \[µg/mg protein\]; * carbamyl protein groups \[µg/mg protein\] were assessed in the serum by competitive enzyme immunoassay (competitive ELISA) using kits from Cell Biolabs Inc, USA.

* potassium (K) \[mmol/l\]; * sodium (Na) \[mmol/l\]; * magnesium (Mg) \[mg/dL\] were assessed in the serum by routine techniques using Cobas Integra 400 plus biochemical analyzer by Roche Diagnostics, USA.

NT-proBNP \[fmol/ml\] - was analyzed in the serum by enzyme immunoassay using the Nt-proBNP kit from Biomedica, Slovakia.

eGFR \[ml/min/1.73m\^2\] - according to the Kidney Disease: Improving Global Outcomes (KDIGO) 2012 recommendations was calculated based on the Modification of Diet in Renal Disease (MDRD) formula: eGFR = 186 x \[creatinine concentration in mg/dl\] - 1.154 x \[age in years\] - 0.203 x \[0.724\] for the female gender.