- Prognostic value of plasma brain natriuretic peptide, urea nitrogen, and creatinine in outpatients >70 years of age with heart failure. Feola, M., Aspromonte, N., Canali, C., Ceci, V., Giovinazzo, P., Milani, L., Quarta, G., Ricci, R., Scardovi, A.B., Uslenghi, E., Valle, R. Am. J. Cardiol. (2005)