Acute decompensated heart failure (ADHF) is the leading cause of admission to hospital in the US, and is associated with high mortality, morbidity, and major cost to the health care system. Much of this cost relates to prolonged hospitalizations from acute deterioration in kidney function (AKI), which in turn is associated with further cardiovascular events such as recurrent ADHF. Strategies for early detection minimization and prevention of AKI would therefore be of tremendous benefit to both the patient and the health care system.

A common reason for hospitalization in ADHF is that of altered volume status and renal impairment. Also, many patients with ADHF have underlying hypertension and/or a recent acute coronary syndrome. Hypertension, diabetes and chronic kidney disease (CKD) are independent risk factors for cardiovascular disease, and diabetes is the leading cause of CKD. Therefore, patients presenting with ADHF are at high risk for CV events, more so if they develop AKI. Therefore, strategies to detect changes in renal status early may allow for more rapid intervention with appropriate drug and other therapies to attenuate AKI and subsequent complications, which may in turn result in prevention of early readmissions with HF.

Most ADHF patients have underlying chronic heart failure (CHF). CHF is a major cost to the health care system. About two thirds of this cost relates to hospitalization for acute deterioration in heart failure (HF). Strategies to minimize or prevent HF hospitalization therefore are of tremendous benefit to both the patient and the health care system.

The most frequent reason for hospitalization in a CHF patient is that of altered volume status and renal impairment. Therefore, as with ADHF, strategies for early detection of changes in renal status may allow for intervention with appropriate drug and other therapies to attenuate, or even prevent, the need for the patient to return to hospital.

Many approaches have been studied in relation to this concept. Deterioration in renal function is a harbinger of a need for hospitalization, and indeed a predictor of medium term mortality. However, current measures of renal function are relatively crude with a considerable lag between an insult to the kidney and its translation to a measurable deterioration in renal function reflected by worsening serum creatinine. Thus, diagnostic tests that evaluate renal injury which are modulated early in the time course of this process may have considerable utility not only in the ADHF setting but also in predicting decompensation in the CHF setting.

Inclusion Criteria:

1. Males and Females

2. Age >18years

3. Confirmed written informed consent

4. Acute decompensated heart failure cohort defined as:

   • Objective evidence of heart failure (of any cause/etiology) demonstrated by typical symptoms/signs combined with an imaging modality (see appendix for criteria)
   • Requirement for intravenous diuretic whilst either an inpatient or in an emergency room setting with intravenous diuretics, vasodilators or inotropes
   • No ejection fraction cut-off will be required, ie both systolic and diastolic heart failure patients can be enrolled

5. Chronic Heart Failure cohort defined as:

   • Echocardiographic evidence of systolic or diastolic heart failure (see appendix for criteria)
   • CHF patients in Class III and class IV NYHA symptoms who have had a minimum of one acute decompensated episode in the previous six months
   • Evidence of impaired renal function (eGFR <60 ml/min)

Exclusion Criteria:

1. Patients with a history of a psychological illness or condition such as to interfere with the patient's ability to understand the requirements of the study
2. Not meeting entry criteria for ADAF (as above)
3. At the discretion of the treating physician

Acute and chronic heart failure