The kit (10) of the invention includes a valve bearing (16) that can be radially deformed. The bearing (16) includes an outer peripheral wall (22) defining a central passage (40) having an axis (X-X&prime). The bearing (16) further includes an inner peripheral wall (24) defining an inner lumen (44) having a radial dimension lower than that of the central passage (40). The kit (10) includes a prosthetic valve (18) to be placed on the inner peripheral wall (24). The inner peripheral wall (24) extends in the central passage axially relative to the outer wall (22). The valve bearing (16) includes a means (26) for maintaining the inner peripheral wall (24) radially remote from the outer peripheral wall (22). The inner peripheral wall (24) and the maintaining means (26) define an inner blood circulation region (56) containing the lumen (44) which is tightly isolated from an outer region (58).
