Acute renal failure is a frequent and severe postoperative complication of cardiac surgery performed under extracorporeal circulation.

It is an independent risk factor for mortality and significantly increases the length of hospital stay.

The origin of renal insufficiency after extracorporeal circulation is multifactorial (long duration of extracorporeal circulation, hemodynamic instability per and post-extracorporeal circulation, prolonged hypotension, transfusion ...).

Nevertheless, an entirely different pathophysiological mechanism, though not recent, is less often mentioned but shows renewed interest. This is the concept of renal venous congestion which may be responsible for impaired renal function in the absence of cardiac dysfunction. Based on Guyton's circulatory model, the investigators approach this systemic venous hypertension through the measurement of the Pmsf-PVC gradient.

Inclusion Criteria:

• age> 18 years

• subject having signed an informed consent

• scheduled heart surgery:

  • Valve replacement
  • Coronary artery bypass

Exclusion Criteria:

• Any urgent surgery or redux
• Severe preoperative chronic renal failure (stage III) defined by GFR <30ml / min
• Existence of rhythm disorders (permanent ACFA) or serious cardiac conduction disorders, patients with Pacemaker
• Preoperative alteration of left ventricular ejection fraction with LVEF <40%
• Major haemodynamic instability with refractory shock defined by dobutamine ≥10μg / kg / min and / or norepinephrine ≥ 1μg / kg / min and / or epinephrine ≥ 0.2μg / kg / min.
• Intra-aortic versus assisted pelvic balloon
• Contraindication to femoral arterial catheterization
• Subject under the protection of justice, subject under guardianship or under tutorship
• Impossibility of giving the subject informed information (subject in emergency situation, difficulties in understanding the subject)

Major patient with scheduled heart surgery