Abstract: The invention relates to an implantable blood pump of the type comprising a shell, a closed deformable bag, an inlet valve and an outlet valve, a drum arranged to roll over a wall of the bag, a bracket mounted to rotate about the axis of the drum and connected by an inextensible flexible component to one of the end edges of the bag, and an electric motor integrated inside the drum and suitable for driving the bracket and the drum in mutual and antagonistic rotation over a fraction of a turn to compress the bag which winds onto the drum to expel blood fluid. According to the invention, the outer shell is rigid and constitutes a sealed housing in which the bag can deform, and the bag is made, at least in part, of a material that is inextensible in two directions so that its original volume remains constant, said bag thus being made insensitive to external underpressure tending to increase its volume while blood fluid is being expelled.

Abstract: Inside a flexible shell (10), a deformable pocket (20) is connected to blood circulation via an inlet valve (30) and an outlet valve (40). The pocket is compressed by a floating assembly comprising a drum (50), and a bracket (60) rotatable about the axis thereof. One of the edges (21) of the pocket (20) is fixed to the drum (50); the opposite edge (22) is connected to the bracket (60) by a traction link (70), for example an inextensible sheet. Relative rotation between the drum and the bracket over a fraction of a turn enables the pocket (20) to be wrapped around the drum (50) and the assembly returns to its starting position under the effect of venous pressure. The disposition of the various components provides a self-adapting lever which limits mechanical losses to rolling friction between the drum and the pocket.