Brain Natriuretic Peptide in Hemodialysis Patients: Predictive Value for Hemodynamic Change during Hemodialysis and Cardiac Function

BACKGROUND: Though brain natriuretic peptide (BNP) is widely used as a clinical marker of cardiac function, there is considerable confusion in the interpretation of its value in hemodialysis (HD) patients whose BNPs are often elevated without cardiac diseases. The aim of the present study is to examine the predictive value of BNP for blood pressure (BP) fall during HD and cardiac function. METHODS: Subjects consisted of 205 (160 males, 45 females; age 66.5 +/- 10.5 years) consecutive uremic patients requiring maintenance HD who were admitted to our hospital during 2001-2004. One hundred and eleven cases had a history of ischemic heart disease. We measured BNP in all cases and collected clinical data including age, sex, duration of HD, blood examination and echocardiography. RESULTS: BNP of all 205 cases ranged from 6 to 16,097 pg/ml (median 831). During HD, the average BP change was -24.5 +/- 20.5 mm Hg, and 111 cases showed a systolic BP reduction >20 mm Hg. BNP did not predict the degree of BP fall. After adjusting confounding factors, the presence of ischemic heart disease, ultrafiltration rate, systolic BP before HD and serum sodium concentration showed a significant correlation with BP change (t = -2.84, -2.76, -4.68 and 2.90; p = 0.005, <0.01, <0.0001 and <0.005, respectively). In relation to echocardiographic indices, BNP >785 pg/ml could predict left ventricular dysfunction (fractional shortening of the left ventricle <30%, sensitivity 73%, specificity 65%). CONCLUSION: The level of BNP could not predict BP fall during HD. However, BNP is a good indicator of cardiac function even in uremic patients.