Plasma brain natriuretic peptide level in maintenance hemodialysis patients: relation to ventricular function and volume status

Background Brain natriuretic peptide (BNP) is widely used as a marker of cardiac dysfunction and a good predictor for both total and cardiovascular disease mortality in end-stage kidney disease patients. BNP levels are elevated in hemodialysis (HD) patients not only due to impaired kidney function but also because other variables such as left ventricular mass index, presence of cardiovascular disease, and volume overload are independent risk factors for high BNP in those patients. This study aims to assess the predialysis BNP levels and intradialytic BNP reduction values as markers of clinically assessed volume status and cardiac dysfunction in HD patients. Patients and methods The study was carried out on fifty maintenance HD patients in the Mansoura Nephrology and Dialysis Unit (MNDU). Complete physical examination before and after the mid-week HD session, including blood pressure, body weight, lower limb (LL) edema, lung auscultation, and neck vein evaluation. Laboratory investigations, including routine investigations, predialysis and postdialysis blood urea, with calculation of urea reduction ratio. Measurement of plasma levels of BNP before and after mid-week HD session using specific ELISA kits. Left ventricular mass was measured by echocardiography, and left ventricular mass index was calculated. Results There is a statistically significant decrease in BNP level after the HD session. There is no statistically significant difference between patients with left ventricular hypertrophy (LVH) and those without LVH as regards predialysis, postdialysis, and intradialytic reduction levels of BNP. Patients with low predialysis BNP levels below 100 pg/ml show a statistically significant decrease in postdialysis urea compared with those with high BNP levels above 100 pg/ml. However, there is a nonsignificant decrease in LVH and a nonsignificant increase in ejection fraction in low BNP level patients. Predialysis BNP shows a significant negative correlation with predialysis and postdialysis weight, while it shows a significant positive correlation with heart rate and serum albumin. The predialysis BNP is a good predictor for LL edema with area under the curve (AUC)=0.827 and P =0.006. The intradialytic BNP reduction level is an excellent predictor for LL edema (AUC=0.925, P <0.001), basal lung crepitations (AUC=0.982, P <0.001), and hypertension (AUC=0.965, P <0.001). Conclusion The presence of LVH in maintenance HD patients does not affect the level of predialysis, postdialysis, and intradialytic BNP reduction levels. The predialysis BNP may be a good predictor for LL edema, while the intradialytic BNP reduction level is an excellent predictor for LL edema, basal lung crepitations, and hypertension in maintenance HD patients.