A sample of plasma and whole blood will be obtained at 4 time points (pre-procedural, early post-procedural, at hospital discharge and during an eventual visite at 3 or 6 months post-procedural). Test for platelet reactivity (LTA, light transmittance aggregometry and Elisa PRI, Platelet reactivity index), multimeric VWF (von Willebrand factor) and blood level of NET: neutrophil extracellular traps(flow cytometry and ELISA) analyses will be performed at the time of blood sampling. Aliquots of plasma will be stored and frozen for further analyses

There are two major objectives:

• To correlate changes in VWF, platelet reactivity and blood level of NET after TAVR with clinical outcomes
• To correlate changes in VWF, platelet reactivity and blood level of NET with antithrombotic regimens after TAVR (direct anticoagulants apixaban versus standard of care, ie Vitamin K antagonist or antiplatelet therapy).

Inclusion Criteria:

• patient undergoing TAVR intervention
• agreement given

Exclusion Criteria:

• severe thrombopenia ( <40.10^9/L)

Patient undergoing TAVR