An anastomotic device (10) implantable into the human or animal body, the device being ring-shaped and having a T-shaped radial cross-section. The device consists of a radially outer annular part (12) and a radially inner annular part (14), the radially inner annular part (14) being axially less wide than the radially outer annular part (12), wherein the radially inner annular part (14) is configured to be interposed as a buttress between two segments to be anastomized (A, B), and sutured thereto, and the radially outer annular part (12) is configured to wrap around the anastomosis site.