Relationship between renal function and plasma brain natriuretic peptide in patients with heart failure

OBJECTIVES This study sought to evaluate the relationship between brain natriuretic peptide (BNP), renal function, and the severity of congestive heart failure (CHF). BACKGROUND Both BNP and renal function are prognostic predictors in CHF patients. METHODS We measured the plasma BNP level in the aortic root and coronary sinus in 366 consecutive patients with CHF. Estimated glomerular filtration rate (eGFR) by the Cockcroft-Gault equation was used as an indicator of renal function. RESULTS By stepwise multivariate analyses, hemodynamic parameters such as left ventricular ejection fraction (LVEF) and left ventricular end-diastolic pressure (LVEDP) but not eGFR were independent predictors of a transcardiac increase (coronary sinus-aortic root) in BNP. Regarding the plasma level of BNP in the aortic root, not only LVEF (p < 0.0001) and LVEDP (p < 0.0001) but also eGFR (p < 0.0001) were independent predictors. Patients were divided into two groups, patients with an eGFR >= 60 ml/min (group 1, n = 229) and patients with an eGFR <60 ml/min (group 2, n = 137). There was no difference in LVEF, LVEDP, or the transcardiac gradient of BNP between the two groups, but the plasma level of BNP in the aortic root was approximately two-fold greater in group 2 than in the group 1. CONCLUSIONS These findings suggest that decreased clearance from the kidney contributes to the elevated BNP in CHF patients with renal dysfiinction, especially in patients with an eGFR <60 ml/min.