Low Dose Intravenous (IV) Infusion of BNP in the Presence and Absence of Acute Type V Phosphodiesterase (PDE V) in Improving Renal Function in Hospitalized Chronic Heart Failure (CHF) Patients With Renal Dysfunction

The purpose of the study is to determine if low doses of BNP can improve renal function in people with chronic heart failure with renal dysfunction, also to determine whether Sildenafil assists with improvement. This study will enroll only hospitalized patients with heart failure.

The broad objective of this protocol is to advance our understanding of the pathophysiological mechanisms of human Cardiorenal Syndrome (CRS) with a specific emphasis upon the biological interaction between diuretic therapy, the renin-angiotensin-aldosterone-system (RAAS) and cyclic 3'-5'-guanosine monophosphate (cGMP) pathway. Chronic heart failure (CHF) as a result of left ventricular systolic dysfunction is a clinical syndrome with high mortality and morbidity. Renal dysfunction is a common and progressive complication of CHF and despite growing recognition of the frequent presentation of combined cardiac and renal dysfunction, or "Cardiorenal Syndrome (CRS)", its underlying pathophysiology is not well understood, with a lack of consensus as to its appropriate management. The main objective of this study is to extend the findings of the applicant's studies in both human and experimental CHF and determine if low dose intravenous (IV) (0.005/Kg/min) administration of BNP in hospitalized decompensated CHF patients with renal dysfunction would improve the renal function. Furthermore, based on our preliminary data, we also sought to assess if PDE V inhibition potentiated these renal enhancing actions. Hypothesis: Low dose IV infusion of BNP in hospitalized decompensated CHF patients with CRS will enhance renal and humoral functions as compared to standard therapy, which will be further potentiated by PDEV inhibition as evident by: Increased sodium excretion, Increased creatinine clearance Decreased plasma creatinine and blood urea nitrogen Suppression of the renin-angiotensin-aldosterone system, Increased renal cGMP generation