title: Cardiorenal syndrome: refining the definition of a complex symbiosis gone wrong.
abstract: BACKGROUND
  The term "cardiorenal syndrome" has generally been reserved for declining renal function in the setting of advanced congestive heart failure. Considering the complex and bi-directional relationship between the heart and the kidneys, we postulate refining the definition to recognize the symbiotic nature of these organs.
  
  
  CONCLUSIONS
  We divide the cardiorenal syndrome into five subtypes: type I, acute cardiorenal syndrome; type II, chronic cardiorenal syndrome; type III, acute renocardiac syndrome; type IV, chronic renocardiac syndrome; and type V, secondary cardiorenal syndrome.
  
  
  CONCLUSIONS
  As early recognition of dysfunction in one organ may prove important in mitigating the spiral of co-dysfunction in both, the need for early and treatment-guiding biomarkers, along with their characteristics, are also discussed.
authors.affiliation: Department of Nephrology, St. Bortolo Hospital, Vicenza, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Ronco
authors.forename: Andrew A
authors.initials: AA
authors.lastname: House
authors.forename: Mikko
authors.initials: M
authors.lastname: Haapio
mesh_terms: D015415:Biomarkers; D006333:Heart Failure / Q000145:classification* / Q000175:diagnosis; D006801:Humans; D051436:Renal Insufficiency, Chronic / Q000145:classification* / Q000175:diagnosis; D013577:Syndrome; D009626:Terminology as Topic
chemical_list: D015415:Biomarkers