Clinical benefits of serum BNP measurement in patients with chronic kidney disease

Jun, Sang Hoon; Choi, Soo Jeong; Kim, Jin Kuk; Hwang, Seung Duk

Abstract

BACKGROUND: B-type natriuretic peptide (BNP) regulates excretion of water and sodium in the kidney, and serum levels of BNP are increased in the settings of decreased ventricular contractility and myocardial overload. Serum levels of BNP and renal function are important prognostic factors in congestive heart failure, and when renal function deteriorates, BNP level is increased. This study aimed to assess the clinical benefits of BNP measurement in patients with chronic kidney disease (CKD) for prediction of congestive heart failure (CHF).
METHODS
Serum levels of BNP were measured in 75 patients with CKD who admitted to Soonchunhyang university Bucheon hospital between the period of April 2003 and April 2004. The clinical data, laboratory findings and echocardiographic findings in these patients were compared retrospectively.
RESULTS
The average BNP level of the 75 patients was 1,645.3+/-1,830.9 pg/mL. There were no differences in BNP levels between K/DOQI CKD stages. Levels of BNP were higher in CKD patients with heart failure compared to those without heart failure. BNP levels showed a negative correlation to left ventricular ejection fraction and significant elevation in patients with pulmonary congestion and weight gain on admission. There was no difference in BNP levels in patients with or without left vetricular hypertrophy, and diabetes mellitus. The best cutoff level of BNP for evaluation of heart failure in patients with CKD was 500 pg/mL, with a sensitivity of 78%, specificity of 53%, positive predictive value of 34%, and negative predictive value of 88%, respectively.
CONCLUSION
BNP levels showed no difference with the degree of renal failure in patients with CKD, and levels were increased with heart failure in patients with CKD. We discovered though, that in patients with CKD the measurement of serum BNP is a useful factor in assessment of coexisting heart failure, volume status and ischemic heart disease.