Relationship between fluid status as assessed by bioimpedance analysis and NT-pro BNP, blood pressure and left ventricular mass index in hemodialysis patients.

Abstract

Maintenance of fluid status within an optimal range and accurate assessment of dry weight (DW) is essential in patients on intermittent haemodialysis (HD) treatment. In this study, we aimed to investigate the association of fluid status measured by bioimpedance analysis (BIA) with N-terminal pro-B natriuretic peptide (NT-proBNP), blood pressure and left ventricular mass index (LVMI) in hemodialysis patients. A total of 45 hemodialysis patients were enrolled in the study. N-terminal pro-B natriuretic peptide (NT-proBNP) was measured by immunoassay. Blood pressure (BP) was recorded. Echocardiographic examinations were performed in all patients. Multifrequency bioimpedance analysis was used to assess pre- and post-dialysis fluid status. Overhydration/ extracellular water (OH/ECW) ratio was used as fluid status index and OH/ECW ratio >0.15 was defined as clinical overhydration. Patients were divided into two groups; overhydrated (OH/ECW>0.15) and non-overhydrated (OH/ECW≤0.15). OH/ECW, systolic blood pressure (SBP), diastolic blood pressure (DBP), LVMI and NT-proBNP levels were significanly reduced after hemodialysis session. The presence of overhydration was more frequent in pre-HD patients compared to post-HD patients (31.1% vs 13.3%, p=0.004). OH/ECW was positively correlated with pre-and post-HD SBP, DBP, LVMI and NT-proBNP (p<0.05). Overhydrated patients had significantly higher values of pre-HD and post-HD SBP, DBP, LVMI and NT-proBNP compared to non-overhydrated patients. In addition, SBP, DBP, LVMI and NT-proBNP levels were significantly reduced after hemodialysis in both overhydrated and non-overhydrated patients group. This study revealed that OH/ECW ratio was significantly associated with SBP, DBP, LVMI and NT-proBNP.