The following are 10 points to remember about this clinical update on the kidney in heart failure (HF):

1. Over 50% of patients with acute and chronic HF, both with preserved and reduced ejection fraction, have an estimated glomerular filtration rate (GFR) <60 ml/min/1.73 m².
2. Worsening renal function (WRF), in patients with a background of renal dysfunction, is a distinct entity. WRF is associated with increased mortality in both inpatients and outpatients, with larger increases in serum creatinine predicting worse outcomes.
3. Unprovoked WRF carries a worse prognosis than that occurring in the setting of hemoconcentration, complete decongestion, or reduction in blood pressure.
4. While patients who have the best diuretic response/efficiency may show the greatest increases in creatinine, these patients still may have the best clinical outcome. At least in acute HF, then, some increase in serum creatinine may be acceptable and not associated with adverse outcomes.
5. WRF associated with the initiation of renin-angiotensin-aldosterone system inhibitors (angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, and mineralocorticoid receptor antagonists) is often not associated with poor outcomes, as there is clearly a beneficial effect of these therapies.
6. There is an association between increased central venous pressure or venous congestion and reduced GFR.
7. Impaired renal function in HF does not necessarily and not simply present as a reduction in GFR, as albuminuria is also frequently observed. There is a stepwise increase in the risk of HF hospitalizations and mortality from normo- to micro- and macro-albuminuria.
8. The majority of risk associated with renal dysfunction is generally restricted to patients with either an elevated N-terminal pro–B-type natriuretic peptide or an elevated blood urea nitrogen-to-creatinine ratio.
9. Although ultrafiltration directly reduces venous congestion, in the CARESS-HF study in patients with WRF and persistent congestion admitted for acute HF, ultrafiltration was actually inferior to stepped pharmacologic therapy.
10. Future studies should help differentiate between true and “pseudo”-worsening renal function (where the clinical status of a patient improves or stays equal even though serum creatinine increases).

Keywords: Albuminuria, Angiotensin Receptor Antagonists, Angiotensin-Converting Enzyme Inhibitors, Blood Pressure, Blood Urea Nitrogen, Central Venous Pressure, Creatinine, Diuretics, Glomerular Filtration Rate, Hospitalization, Hyperemia, Kidney, Mineralocorticoid Receptor Antagonists, Natriuretic Peptide, Brain, Prognosis, Renal Insufficiency, Renin-Angiotensin System, Ultrafiltration

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