An endovascular prosthesis (200) includes a stent-graft (240) and an external coagulation inducer (750). The stent-graft (240) includes a first portion (734A) of structural strut members (730) and a first portion (736A) of a graft member (732), which, when the endovascular prosthesis (200) is unconstrained in a radially-expanded state, together are shaped so as to define a blood-carrying tubular structure defining a lumen. The external coagulation inducer (750) includes an extra-luminal skirt (760), which includes a second portion (734B) of the structural strut members (730) and a second portion (736B) of the graft member (732), and is configured to assume: (i) when the endovascular prosthesis (200) is removably disposed in a delivery sheath, a radially- compressed delivery state, in which the structural strut members (730) of the first portion (734A) do not coincide with the structural stent members (730) of the second portion (734B), and (ii) when the endovascular prosthesis (200) is unconstrained, a radially- expanded state, in which the extra-luminal skirt extends (760) radially outward from an external surface (252) of the stent-graft (240).
