Study of Platelet Activation by Severe Aortic Stenosis and Its Correction by Transcatheter Aortic Valve Implantation

"Peripheral venous citrated blood will be collected just before and 10-15 min after the implantation of the valve. Samples will be obtained after starting the infusion of contrast media. In peripheral venous blood before 24 h and after the procedure and at hospital discharge, 4-6 days when the usual transient thrombocytopenia after TAVI has recovered.~The results will be used to analyse the kinetics of haematological changes in peripheral blood following aortic valve replacement.~Platelet activation will be monitored by flow cytometry to assess the expression of specific membrane markers and the phosphorylation of signalling proteins, as well as the formation of platelet/monocyte aggregates."

In this group, only one sample (2 tubes filled with 4.5 ml, i.e. 9ml) will be obtained in venous peripheral blood to establish reference values in age-matched, aspirin-treated, atherosclerotic population.