Bioelectrical Impedance Vector Analysis and Brain Natriuretic Peptide in the Evaluation of Patients with Chronic Kidney Disease in Hemodialitic Treatment

Abstract

Introduction: Setting dry weight (DW) in hemodialysis (HD) patients is still a hard issue. Several clinical, hematochemical, and instrumental parameters have been considered. In the last years, bioelectrical impedance vector analysis (BIVA) became the main method to evaluate body composition and water body percentage. However, it is still difficult to assess the nutritional status and identify a correct DW in HD patients.

Aim: The aim of the study was to set DW and nutritional status, combining BIVA with phase angle (PhA) and serum brain natriuretic peptide (BNP) in HD patients.

Methods: We evaluated PhA and BNP modifications before (T0), after HD section (T1), and after 60 days (T2), in all patients treated in our HD center.

Results: A total of 50 patients (36 males) with a mean age of 70.1 ± 8.85 years were recruited. We did not report significant changes in BNP and PhA between T0 and T1, while they were significantly different between T0 and T2. We also reported a significant difference between T0 and T2 in ECW/TBW, while we did not show significant variations in ECM/BMC between T0, T1, and T2 indicating a stability of the nutritional status. PhA, BNP, and ECW/TBW returned to a normal value in patients in which we reached a DW, also considering clinical parameters such as blood pressure and antihypertensive therapy. The weight loss obtained with the evaluation of the BIVA and the BNP was 1.2-5.7 kg, greater than that calculated empirically which stood at around 0.9-4.3 kg.

Conclusion: We suggest to carry out BIVA with PhA combined with BNP to assess an adequate DW and evaluate a correct nutritional status in HD patients.

Keywords: Bioelectrical impedance vector analysis; Brain natriuretic peptide; Dry weight; Hemodialysis; Phase angle.