Significance of plasma B-type natriuretic peptide in hemodialysis patients: blood sample timing and comorbidity burden.

Plasma B-type natriuretic peptide (BNP) concentration was evaluated in end-stage renal disease patients to verify if measurements before or after the session could furnish different information. BNP levels in plasma from 52 hemodialysis (HD) patients were measured both before and after the first session of the week. Echocardiographic studies were also performed and patients were followed over a period of 28 months. BNP removal from plasma was influenced by equilibrated Kt/V and patient characteristics. Initial plasma BNP concentration was correlated both with cardiac systolic function (LVEF) and mortality rate, independent of blood sample timing (before or after HD). A relative risk of death of 2.67 was found for plasma BNP levels above 335 pg/mL or 232 pg/mL, before and after HD, respectively. Higher BNP levels were observed in patients with higher burden of comorbidity, as measured by the Charlson Comorbidity Index; however, statistical significance was obtained only for BNP measured before HD. In conclusion, measurement of plasma BNP could give a valuable risk stratification of HD patients while cutting costs, by confining echocardiographic studies only to cases with BNP levels above the established cutoff values.