Heart failure and renal insufficiency often coexist in the same patient. Customarily, this condition is described as 'cardio-renal syndrome'. In this situation mortality increases significantly as the renal dysfunction worsen. Treating these patients is challenging, due to their instability (congestion needs to be controlled, while maintaining, or not worsening, organ perfusion), making in-hospital and mid-term mortality hard to improve. Congestion represent the key characteristic of this syndrome, and its treatment is far from been standardized, considering that the condition represent, still, the first cause of re-hospitalization for these patients. Present treatment should be modified, because barely accounts for renal physiology and is responsible for 'resistance to diuretics', which eventually becomes iatrogenic, and non 'sodium-dependent' hyponatraemia. It is then important to emphasize the importance of the 'sequential nephron blockade', to decrease the number of 'non-responder' to diuretics, and the possible role of the 'acquaretics'.
Keywords: Diuretics; Heart failure; Renal insufficiency.