Cardiorenal syndrome: understanding the connections between cardiac and renal disease.

Renal and cardiac diseases are nearly ubiquitous in hospitalized patients and common causes of morbidity in outpatients. Although the connection between the heart and kidneys is relatively well known in the medical community, a more formal classification for the clinical interplay of the two systems has been developed only recently. Cardiorenal syndrome was described by Italian nephrologist Claudio Ronco in 2008. This classification allows for justification of management strategies in these complex patients and will guide further research studies.