Blood pump with in-situ attaching motor stators

1. A blood pump, comprising:

a housing having an interior and an exterior, the housing defining a housing axis and an axial direction along the housing axis;

a pump rotor configured to be received within the interior of the housing, the pump rotor including a magnet; and

a stator having a plurality of stator units, each stator unit having a coil and a delivery configuration and an operative configuration, the plurality of stator units in the delivery configuration having a delivery diameter, each stator unit being configured to slide successively along a common shaft, the plurality of stators units in the operative configuration being configured to:

be disposed around the exterior of the housing; and

form an assembled pump having a diameter greater than the delivery diameter.

2. The blood pump of claim 1 , wherein the housing defines a housing axis and axial directions along the housing axis, each coil within each unit of the plurality of stator units including a coil axis and an electrical conductor arranged in one or more turns surrounding the coil axis, the stator in the operative configuration having the units disposed around the housing axis with the coil axes of the units transverse to the housing axis.

3. The blood pump of claim 2 , wherein in the delivery configuration:

the stator has a delivery axis;

the coil axes are transverse to the delivery axis; and

at least one of the units is offset from another one of the units in a direction along the delivery axis.

4. The blood pump of claim 3 , wherein in the delivery configuration the units of the stator are disposed in a row along the delivery axis, with each of the units being offset from an adjacent one of the units in a direction along the delivery axis.

5. The blood pump of claim 3 , wherein the housing has an exterior surface including one or more arcuate surfaces coaxial with the housing axis, and wherein each of the units has an interior surface in the form of a partial surface of revolution around a unit axis transverse to the coil axis of that unit, the interior surfaces of each units confronting the arcuate surfaces of the housing when the stator is in the operative configuration.

6. The blood pump of claim 1 , wherein the stator includes a flexible member including one or more coils, the flexible member extending around the housing when the stator is in the operative condition.

7. The blood pump of claim 6 , wherein when the stator is in the operative configuration, the flexible member forms a tube and the pump housing is disposed within the tube, and wherein the flexible member is folded when the stator is in the delivery configuration.

8. A blood pump implantation assembly, comprising:

a delivery device;

a pump mounted to the delivery device proximate a distal end thereof, the pump including a pump housing, a rotor configured to be disposed within the pump housing and a stator having stator units, the pump in the operative configuration having the units disposed around the housing axis with the coil axes of the units transverse to the housing axis;

the pump in a delivery condition having the stator units offset from the pump housing and having the stator define a first diameter, the delivery device being configured to transition the pump from the delivery condition to an operative condition in which the stator is in an operative configuration disposed around the pump housing and defines a second diameter larger than the first diameter, each stator unit being configured to slide successively along a common shaft in the delivery condition.

9. The assembly of claim 8 , wherein the housing has a housing axis extending proximally and distally when the pump is in the delivery condition, the stator including a plurality of units, each unit including a coil having a coil axis and an electrical conductor arranged in one or more turns surrounding the coil axis.

10. The assembly of claim 9 , wherein in the delivery configuration the coil axes are transverse to a major longitudinal axis of the delivery device and at least one of the units is offset from another one of the units along the major longitudinal axis.

11. The assembly of claim 10 , wherein in the delivery configuration the units of the stator are arranged successively along the major longitudinal axis.

12. The assembly of claim 11 , wherein the delivery device is configured to advance the units along the major longitudinal axis toward the pump housing to bring the pump from the delivery condition to the operative condition.

13. The assembly of claim 8 , wherein the stator includes a flexible member including one or more coils, the flexible member extending around the housing when the pump is in the operative condition.

14. The assembly of claim 13 , wherein the flexible member is a tube having a wall, the wall defining a bore and the housing being disposed within the bore when the pump is in the operative condition, the flexible member being folded along one or more fold axes when the pump is in the delivery configuration.

15. The assembly of claim 8 , wherein the pump is releasably mounted to the delivery device.

16. A method of implanting a blood pump in the body of a living subject, comprising:

advancing the pump into the body of the subject to a target location, the pump being in a delivery condition in which a stator of the pump having stator units is separate from a pump housing and the pump has a delivery diameter; and

sliding the stator units successively along a common shaft; and

transitioning the pump to an operative condition, the stator being disposed around the pump housing and the pump has an operative diameter greater than the delivery diameter when in the operative condition.

17. The method of claim 16 , further comprising applying electrical power to the stator to provide a rotating magnetic field within the housing while the pump is in the operative condition a rotor within the housing is rotated and the rotor impels blood through the housing.

18. The method of claim 17 , wherein advancing the pump into the body of the subject to a target location step includes advancing the pump through vasculature of the subject.

19. The method of claim 16 , wherein transitioning the pump to an operative condition includes at least one from the group consisting of retracting and advancing a portion of a delivery device, the delivery device including the stator in the delivery condition.