Abstract: Apparatus (20) is provided for creating a connection between a first body lumen (114) of a subject and a second body lumen (116) of the subject. The apparatus (20) includes a first engagement portion (102) configured to engage a wall of a first body lumen (114), a second engagement portion (104) that engages a wall of a second body lumen (116), and a cylindrical connecting portion (106) connecting the first engagement portion (102) to the second engagement portion (104). The connecting portion (106) defines a channel therethrough for passage of fluid from the inner space of the lumen (114), through the flow channel, and into the inner space of the body lumen (116). The apparatus also includes a projection (200) coupled to the second engagement portion (104), and surrounds an external surface of the wall of the lumen (116). Other embodiments are also described.