Researchers are observing the values of proEnkephalin (PENK) via a blood draw in hospitalized patients that are volume overloaded requiring diuresis. If changes in PENK are found, physicians may predict values of change in kidney function during treatment.

The purpose of this study will be to probe if values of proEnkephalin, called PENK in this proposal, can identify those patients who develop AKI. This biomarker is an opioid that is rapidly released in response to renal injury. At a cut-off value of 100pmol/L, it has been reported to have excellent sensitivity and specificity for detecting renal injury. PENK has been shown to be prognostic of WRF and outcomes in patients with acute heart failure but requires evaluation of efficacy in detecting AKI in standard of care clinical practice settings. In this study we propose to evaluate the baseline presence of plasma and/or serum levels of biomarkers of renal injury and changes in these biomarkers during the course of in-hospital intravenous diuretic therapy. The question is if threshold values of the biomarkers can be identified and if those threshold values would indicate a clinically significant change in renal function that would warrant a change in diuretic therapy to occur. In this context the quantitative assessment of intravascular volume will provide objective corroboration as to volume status in relation to biomarker levels and changes during treatment. If this approach can be proven to be fruitful, it would be anticipated that a subsequent study, a clinical trial, to test the hypothesis that biomarkers of AKI, specifically PENK, could be used to identify and avoid AKI in hospitalized patients with decompensated HF.

Inclusion Criteria:

• Age > 18 years
• LVEF <50% measured within 6 months of index hospitalization
• Clinically identified volume overload with at least one sign of volume overload (pre-admission fluid weight gain, edema, increased DOE, PND, orthopnea, JVD on examination) and a need for intravenous diuretic therapy

Exclusion Criteria:

• Baseline sCr >3.0mg/dL and K+ <3.0 and >5.5mEq/L
• Hemoglobin < 9.0g/dL
• Systemic systolic blood pressure consistently <100mm Hg
• Patients being treated with hemodialysis, CKD stage 5 or s/p renal transplantation
• S/P cardiac transplant or LVAD implantation/total artificial heart
• Pregnancy or of child bearing potential
• Allergy to iodine
• Unable to provide informed consent to participate in the study