Cardio-renal syndromes: report from the consensus conference of the acute dialysis quality initiative

Abstract

A consensus conference on cardio-renal syndromes (CRS) was held in Venice Italy, in September 2008 under the auspices of the Acute Dialysis Quality Initiative (ADQI). The following topics were matter of discussion after a systematic literature review and the appraisal of the best available evidence: definition/classification system; epidemiology; diagnostic criteria and biomarkers; prevention/protection strategies; management and therapy. The umbrella term CRS was used to identify a disorder of the heart and kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction in the other organ. Different syndromes were identified and classified into five subtypes. Acute CRS (type 1): acute worsening of heart function (AHF-ACS) leading to kidney injury and/or dysfunction. Chronic cardio-renal syndrome (type 2): chronic abnormalities in heart function (CHF-CHD) leading to kidney injury and/or dysfunction. Acute reno-cardiac syndrome (type 3): acute worsening of kidney function (AKI) leading to heart injury and/or dysfunction. Chronic reno-cardiac syndrome (type 4): chronic kidney disease leading to heart injury, disease, and/or dysfunction. Secondary CRS (type 5): systemic conditions leading to simultaneous injury and/or dysfunction of heart and kidney. Consensus statements concerning epidemiology, diagnosis, prevention, and management strategies are discussed in the paper for each of the syndromes.

Figure 1

Pathophysiology and definitions of the five subtypes of cardio-renal syndrome (modified by Ronco et al.).

Figure 2

In cardio-renal syndromes, there are two important aspects: the first is the sequence of organ involvement and the second is the bi-directionality of signalling leading to a vicious cycle. Another important aspect is the time frame in which the derangements occur (chronic or acute). In all cases, there are moments in which prevention is possible, in others mitigation of the insult is potentially feasible, in others, therapeutic strategies must be implemented. At different times, a crucial role is played by imaging techniques and biomarkers enabling the clinician to make an early diagnosis, establish illness severity, and to potentially predict outcomes. This flowchart describes a series of conditions indicating that patients may move from one type to another of cardio-renal syndromes.