Acute kidney injury (AKI) is a frequent disease in conventional hospital departments and in intensive care units. It's associated with a high risk to develop chronic kidney disease (CKD), even after a single small AKI episode. It's also associated with an important morbi-mortality, particularly cardiovascular (CV). Some studies have already showed a link between AKI and CV risk but pathologic mechanisms implicated are still unknown. In AKI and CKD, numerous substances, called uremic toxins (UT) are accumulating in blood. In CKD, those toxins, and particularly Indoxyl sulfate (IS), are known to have cardiac and vascular deleterious consequences. However, in AKI, whether acute accumulation of UT may trigger CV complications is unknown.

The purpose of this study is that during AKI, a high UT concentration, in particular IS, would be associated with early vascular and cardiac dysfunctions that can be characterized by the persistence of an accelerated pulse wave velocity (PWV). The main objective is to evaluate the correlation between UT concentrations (especially IS) and arterial stiffness (PWV measurement) at three months of an AKI episode in conventional hospital departments and in the intensive care unit of nephrology.

Inclusion Criteria:

• Age over 18 years old.
• Patients hospitalized in conventional hospital departments and in intensive care units of nephrology.
• Patients with moderate to severe AKI (KDIGO 2 or 3) without dialysis.
• AKI from functional or organic aetiology

Exclusion Criteria:

• Patients with severe CKD (GFR<45ml/min/1.73 m2) or with kidney transplants.
• Patients with AKI from septic or obstructive aetiology.
• Patients with AKI from toxic aetiology whose toxic would be also responsable of cardia toxicity.
• Patients with sepsis or blood inflammation.
• Patients with severe chronic cardia dysfunction.
• Patients with arrhythmia or complete heart block.
• Patients with peripheral artery occlusive disease.
• Pregnancy.
• Patients on palliative care.