An endovascular prosthesis (100) comprises a structural member (131), which defines, when the prosthesis (100) assumes an expanded state, a substantially tubular structure (111), and two wings (107, 108), which are coupled to a proximal end (118) of the tubular structure (111). If the wings (107, 108) are placed within and in contact with a right circular cylinder (102), which has a diameter of between 2.5 and 3 cm, such that a distal end (119) of the tubular structure (111) is outside the cylinder (102): (a) an axis (116) of the tubular structure (111) defines an angle of between 75 and 90 degrees with an axis (106) of the cylinder (102), (b) the wings (107, 108) at least partially occupy respective arcs (103A, 103B) of the cylinder (102), at least one of which arcs (103A, 103B) has an angle of no more than 180 degrees, and (c) the wings (107, 108) have respective greatest axial lengths (104) along the cylinder axis (106), at least one of which is at least 1.5 times a diameter (122) of the tubular structure (111).
