Plasma myeloperoxidase, NT‐proBNP, and troponin‐I in patients on CAPD compared with those on regular hemodialysis

Myeloperoxidase (MPO) is a hemoprotein that is released during inflammation and may lead to irreversible protein and lipid modification, increasing levels of oxidized low density lipoprotein, and promoting athrogenesis. Recently, it has been considered as a risk factor for cardiovascular diseases. Similarly, the measurement of carotid intima-media thickness gives an indication about the degree of atherosclerosis and prediction of clinical cardiovascular events. Elevated white blood cells counts may indicate a state of acute inflammation and follow its progression. Dialysis patients are at a high risk of developing cardiovascular disease compared with healthy subjects. The role of N-terminal pro-brain natriuretic peptide and increased cardiac troponin in identification and prognostication of cardiovascular diseases in end-stage renal disease patients has been investigated. The current study aimed to evaluate plasma MPO and its possible relationship with carotid intima-media thickness, troponin I, N-terminal pro-brain natriuretic peptide (NT-proBNP), and insulin resistance as measured by homeostatic model assessment (HOMA index) in a cohort of Saudi patients who are undergoing hemodialysis (HD) vs. continuous ambulatory peritoneal dialysis for end-stage renal disease. Plasma MPO was significantly higher in patients on continuous ambulatory peritoneal dialysis (CAPD) than in those on HD and in normal subjects (P<0.001). Conversely, NT-proBNP plasma levels were significantly higher in patients on HD (both predialysis and postdialysis) than in those on CAPD (P<0.01) and than normal subjects. Similarly, plasma troponin-I levels were significantly higher in patients on HD compared with those of CAPD and than normal subjects (P<0.001). Plasma troponin-I and NT-proBNP levels were positively correlated in the 3 groups namely those on CAPD, Pre-HD, and post-HD (r: 0.464 and P=0.047; r: 0.330 and P=0.013; and r: 0.452 and P=0.024), respectively. There was no correlation between the MPO level and carotid intima-media thickness (P>0.05). However, plasma MPO level correlated positively with the white blood cell count in patients on CAPD and in those on HD (P<0.05). Our findings suggest an increased oxidative stress in CAPD patients compared with HD patients, while the reported difference in plasma NT-proBNP and troponin-I may be related to the rapid decline of residual renal function in HD and type of membrane used in the HD dialysis procedure itself.