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

Inclusion Criteria: * Patients admitted to St Mary's Hospital, Mayo Clinic Rochester MN with NYHA class III-IV decompensated CHF with renal dysfunction as Calculated creatinine clearance of equal or less than 60 ml/min but greater than 20 ml/min using the Cockcroft-Gault formula. Exclusion Criteria: * Cause of acute renal dysfunction can be reasonably ascribed to factors other than heart failure or its treatment * Known intrinsic renal diseases or renal artery stenosis of =\>50% * Patients taking Nitrates within the previous 24 hours * Patients needing emergency coronary revascularization or those who may have rapidly changing cardiac function (i.e. patients with acute myocardial infarction or shock) * Peritoneal or hemodialysis within 90 days or anticipation that dialysis or ultrafiltration of any form will be required during the study period * Systolic blood pressure \< 90 mmHg or cardiogenic shock. * Requirement of pressors for maintenance of blood pressure. * Intra-aortic blood pump use. * History of significant uncorrected renal artery stenosis as defined by \>50% stenosis. * Severe aortic or mitral stenosis or significant LV outflow tract obstruction. Hgb \< 10 mg/dL * Pregnant or nursing women. * Contraindication to nesiritide. * Inability to have NSAID dose held for up to 30 hours, if being treated with these medications. * Administration of radiocontrast medium within 7 days of enrollment or anticipated use of such agents during the study