Stent pump

1. A stent pump for intravascular, intraventricular or intraatrial placement inside the human heart comprising:

a preferably tubular housing having an inlet and an outlet,

an impeller, and

a stream former, wherein the impeller and optionally the stream former are arranged within the housing, wherein the stream former is arranged downstream of the impeller, and the housing, the stream former and/or the impeller are deployable from a first position, in which the housing, the stream former and/or the impeller are folded for being arranged within a delivery device, into a second, expanded position, in which the housing, the stream former and/or the impeller are deployed, characterized in that the housing comprises an inlet section and an impeller section, the inlet section being arranged upstream of the impeller section, whereby the inlet section comprises a tapering cross section at the orifice to the impeller section, which narrows towards the impeller section and the housing comprises means for imparting a rotational flow component to the blood, namely guiding elements or vanes protruding inwardly from the wall of the housing, which are arranged in the inlet section of the housing, wherein a direction of rotation resulting from the rotational flow component corresponds to a direction of rotation of the impeller.

2. The pump of claim 1 , characterized in that the impeller is arranged to be displaceable in an axial direction relative to the housing between a first and a second axial position, wherein in its first axial position the impeller is arranged outside the housing, when the impeller and the housing are folded for being arranged within a delivery device, and in its second axial position the impeller is arranged within the housing, when said housing and said impeller are deployed.

3. The pump of claim 1 , characterized in that the housing and/or the stream former and/or the impeller are made of a shape-memory alloy, preferably of nitinol.

4. The pump of claim 1 , characterized in that the pump further comprises a preferably flexible drive for driving a mandrel arranged within the housing and fixed to the impeller.

5. The pump of claim 4 , characterized in that it further comprises a magnetic coupling, which couples the mandrel to the drive.

6. The pump of claim 4 , characterized in that the mandrel is arranged in a semipermeable tube with a hygroscopic inner surface and a hyperosmolar outer surface.

7. The pump of claim 1 , characterized in that the housing has a wall that is impermeable to blood.

8. The pump of claim 7 , characterized in that the wall of the housing is configured as a flexible hose or as a cage made of wire or cut from a stent tube and carrying a flexible jacket, a cage or a wire helix made from a laminated wire, the lamination being made of PET, silicone or PTFE.

9. The pump of claim 1 , characterized in that the housing comprises fixing means for fixing the housing in a vessel.

10. The pump of claim 9 , characterized in that the fixing means comprise a radially expandable and blood permeable element or a radially expandable cage, that surrounds the housing.

11. The pump of claim 10 , characterized in that the radially expandable element is formed by a distal section of the housing, which in its expanded state preferably widens in the flow direction.

12. The pump of claim 10 , characterized in that the impeller and optionally the stream former is arranged in the radially expandable element.

13. The pump of claim 1 , characterized in that the impeller comprises a conical body that carries vanes.

14. The pump of claim 13 , characterized in that the vanes of the impeller have a hyperboloid shape.

15. The pump of claim 13 , characterized in that the vanes of the impeller are made of preferably foldable wires and/or sheets.

16. The pump of claim 1 , characterized in that the stream former comprises substantially parallel fins extending in an axial direction.