Relation Between the Value of Platelet Clot Stiffness (PCS) Obtained by Sonorheometric Method of Delocalized Hemostasis (QUANTRA®), and the Presence of a Disorder of Primary Hemostasis, in Cardiac Surgery Patients. PLAQUA-Study

Study of the Relationship Between the Value of PCS (Platelet Clot Stiffness - Parameter Evaluating Platelet Participation in Clot Formation) Obtained by Sonorheometric Method of Delocalized Hemostasis (QUANTRA®), and the Presence of a Disorder of Primary Hemostasis, in Cardiac Surgery Patients. PLAQUA-Study

The goal of this study is to determine whether the Platelet Clot Stiffness (PCS) measured by QUANTRA® is predictive of an abnormality in primary haemostasis intraoperatively in cardiac surgery performed under extracorporeal circulation.

The aim is to compare the assessment of platelet function by QUANTRA® (data called PCS, obtained in around ten minutes) with laboratory tests which are validated, but which cannot be used in current practice (response time too long, in particular). We are therefore seeking to determine whether QUANTRA is reliable in the search for a primary hemostasis anomaly, defined by significant thrombocytopenia (platelet count below 100G/L), and/or a prolongation of platelet occlusion time measured by PFA-200® (normal or increased).

This clinical research project will last 12 months. It will take place in the cardiac surgery operating room at CHU Félix Guyon, and will involve 100 patients.

Patients who have consented to participate in this research project will be managed in the operating room in the usual way, with no change to their usual care (in terms of treatments received). At the end of the surgery, we will add 3 blood samples (maximum 8.1ml) for analysis to assess platelet function and compare with QUANTRA data.

This blood sample will be the only procedure performed. Medical management remains standard and will not be disrupted by this test.

Inclusion Criteria:

Patients

• Hospitalized for scheduled cardiac surgery performed under extracorporeal circulation, including coronary bypass, valve replacement, aortic arch and combined surgeries.

Exclusion Criteria:

Patients:

• with preoperative hematocrit < 35% and preoperative platelet count < 80,000 G/L (validity of PFA-200® Test)
• With known congenital or acquired Willebrand's disease, or known platelet dysfunction.
• On double antiaggregation, not discontinued at the time of surgery
• Vulnerable patients: minors or protected adults, pregnant women, patients not affiliated to the social security system.
• Emergency situation