trated in FIGS. 8 to 10 are, respectively, similar to the solutions represented in FIGS. 5 to 7, which have just been described, with the difference represented by the presence, inside the prosthesis 1 of FIGS. 8 to 10, of a stent element designated as a whole by 30. [0140] The positioning and/or spreading-out in situ of devices such as the ones illustrated in the figures of the attached drawings