N-terminal proBNP—Marker of Cardiac Dysfunction, Fluid Overload, or Malnutrition in Hemodialysis Patients?

Abstract

Background and objectives: N-terminal probrain type natriuretic peptide (NTproBNP) has been proven to be a valuable biomarker for predicting cardiac events and mortality in the hemodialysis population. However recent reports have suggested that NTproBNP is a marker of volume overload rather than one of cardiac dysfunction. Therefore this study investigated the effect of fluid volume status on NTproBNP.Design, setting, participants, & measurements: Volume status was determined pre-and postdialysis in 72 stable hemodialysis outpatients by multifrequency bioimpedance, and the relationship to NTproBNP values was examined.Results: The mean and median NTproBNP values were 931.9 ؎ 230 and 242 (90 to 688) pmol/L, respectively. On simple correlation, NTproBNP was associated with markers of volume overload and cardiac dysfunction. However, on logistical regression analysis, the strongest association was with the predialysis ratio of extracellular water/total body water (␤ 26.6, F29.6, P ‫؍‬ 0.000), followed by postdialysis mean arterial blood pressure (␤ 0.14, F17.1, P ‫؍‬ 0.000), dialysate calcium concentration (␤ ؊1.19, F14.1, P ‫؍‬ 0.002), and change in extracellular fluid volume with dialysis (␤ 0.27, F7.4, P ‫؍‬ 0.009) Conclusions: In this study, NTproBNP was not associated with cardiac dysfunction as assessed by transthoracic echo or nuclear medicine scintigraphy but was dependent on factors associated with volume overload. However, because bioimpedance results can also be affected by malnutrition with loss of cell mass, NTproBNP may be elevated not only in patients with volume overload, but also those with malnutrition.

Evaluation of volume overload by bioelectrical impedance analysis, NT-proBNP and inferior vena cava diameter in patients with stage 3&4 and 5 chronic kidney disease

“…28 In another study by Booth et al, a strong association was found between NT-proBNP and the predialysis ratio of extracellular water/total body water. 29 Our study agrees with these previous reports by showing that NT-proBNP was significantly higher in the CKD patients with overhydration compared to patients without, and it was significantly positively correlated with OH/ECW (reflecting overhydration).…”

Does peritoneal dialysate affect body composition assessments using multi-frequency bioimpedance in peritoneal dialysis patients?

“…Multi-frequency bio-impedance is being increasingly used to assess volume status in peritoneal [17] and haemodialysis patients [18]. As the water content of different tissues varies, for example being greater in muscle compared to fat, bioimpedance can be used to assess body composition, with comparable results to dual energy X ray absorptiometry [19].…”

NT-proBNP and Troponin T Levels Differ after Haemodialysis with a Low versus High Flux Membrane

“…Notable is that TnT has molecular size of 37 kDa but also exists as fragments ranging in size from 8 kDa to 30 kDa (26,27), and troponin I has size between 21 kDa to 24 kDa (28). The cardiac markers are all predictors of increased risk of mortality (13,17,18,21,24,(29)(30)(31)(32).…”