B-Type Natriuretic Peptide (BNP) and Amino-Terminal proBNP in Patients With CKD: Relationship to Renal Function and Left Ventricular Hypertrophy

Background: Most patients with chronic kidney disease (CKD) develop cardiovascular complications. Natriuretic peptides are novel markers that can be used to identify and monitor heart failure, but the effect of renal disease on these markers is not fully understood. The aim of the present study is to explore the relationship among circulating B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) concentrations and clinical variables in a cohort of patients with CKD. Methods: Plasma BNP and NT-proBNP concentrations and left ventricular (LV) mass index were measured in 213 predialysis patients with CKD. Results: Plasma BNP and NT-proBNP concentrations increased with declining estimated glomerular filtration rate (GFR; P < 0.0001). Estimated GFR had an independent effect on plasma BNP (P = 0.0028) and, to a greater extent, plasma NT-proBNP (P < 0.0001) concentrations: mean BNP concentration increased by 20.6% per 10-mL/min/1.73 m2 (0.17-mL/s) reduction in estimated GFR compared with 37.7% for NT-proBNP. NT-proBNP/BNP ratio increased with CKD stage (P < 0.0001). Median plasma BNP and NT-proBNP concentrations were greater in patients with LV hypertrophy (P < 0.0001), and LV mass index had an independent effect on both BNP (P = 0.0223) and NT-proBNP (P < 0.0017). Conclusion: Estimated GFR and LV mass index have independent effects on both plasma BNP and NT-proBNP concentrations in patients with CKD. NT-proBNP appears to be affected more by declining kidney function, in keeping with the hypothesis that its clearance is predominantly renal. Our data have significant implications for application of these peptides as cardiac biomarkers in patients with CKD.