Blood pump

• US 6,245,007 B1
• Filed: 01/28/1999
• Issued: 06/12/2001
• Est. Priority Date: 01/28/1999
• Status: Expired due to Term

• Current Assignee: Terumo Cardiovascular Systems Corporation (Terumo Corporation)
• Original Assignee: Terumo Cardiovascular Systems Corporation (Terumo Corporation)
• Inventors: Bedingham, William, Castro, Gustavo H., Gonzalez, Bernard A.
• Primary Examiner(s): LAYNO, CARL HERNANDZ
• Application Number:
  US09/239,440
• Time in Patent Office: 866 Days
• Field of Search: 600/16, 600/18
• US Class Current: 600/16
• CPC Class Codes: A61M 60/148 in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices
• CPC Class Codes: A61M 60/165 implantable in, on, or around the heart
• CPC Class Codes: A61M 60/174 discharging the blood to the ventricle or arterial system via a cannula internal to the ventricle or arterial system
• CPC Class Codes: A61M 60/216 including a rotating member acting on the blood, e.g. impeller
• CPC Class Codes: A61M 60/414 transmitted by a rotating cable, e.g. for blood pumps mounted on a catheter
• CPC Class Codes: A61M 60/812 Vanes or blades, e.g. static flow guides
• CPC Class Codes: A61M 60/824 Hydrodynamic or fluid film bearings
• CPC Class Codes: A61M 60/829 having a purge fluid supply
• CPC Class Codes: A61M 60/865 Devices for guiding or inserting pumps or pumping devices into the patient's body

Abstract

A blood pump comprising a pump mechanism having an outer sleeve, an inner sleeve, and an impeller. The pump mechanism is movable between a closed and preferably retracted position wherein one or both of an inlet port and an outlet port are sealed by the inner and/or outer sleeve for inserting the pump mechanism into the heart, and an open and preferably extended position wherein the inlet and outlet ports are open to allow the impeller to pump blood through the ports. The pump mechanism preferably retracts so that it has less length and is more readily maneuvered when it is in its closed position. Also disclosed are a bearing portion received within a cap of the impeller with a flow of lubricating liquid between the bearing portion and cap, and a method of using the pump.

Claims

1. An intravascular blood pump, comprising:

a cable assembly having;

an outer sheath;

an inner sheath partially enclosed within the outer sheath; and

a drive cable partially enclosed within the inner sheath; and

a pump mechanism comprising

an outer sleeve having a port therein and being attached to the outer sheath;

an inner sleeve in sliding engagement with the outer sleeve, the inner sleeve being attached to the inner sheath; and

an impeller mounted within at least one of the inner and outer sleeves, the impeller being attached to the drive cable;

the inner and outer sleeves being movable relative to one another between;

a retracted position wherein the port is sealed by the inner sleeve; and

an extended position wherein the port is open to permit fluid communication through the port with the impeller.

2. The intravascular blood pump according to claim 1 further comprising a locking mechanism attached to one of the inner sheath or the outer sheath and adapted to engage the other sheath for locking the pump mechanism in the extended position.

3. The intravascular blood pump according to claim 1 wherein the inner sleeve further comprises:

a support member attached to the inner sheath proximally of the impeller, and

a distal member adjacent the impeller distally of the impeller.

4. The intravascular blood pump according to claim 3 wherein the port constitutes a first port, the pump mechanism further having a second port adjacent the distal member, the second port being open when the pump mechanism is in the extended position and is closed by the outer sleeve when the pump mechanism is in the retracted position.

5. The intravascular blood pump according to claim 3 wherein

the inner sheath is attached to the support member by means of a spindle, the spindle having an interior lumen, a flange and a bearing portion, the bearing portion having at least one slot and at least one fluid connection between the interior lumen and the slot;

and

the impeller comprises a cap attached to the drive cable, the cap having a flange disposed adjacent the flange on the spindle;

the blood pump further comprises means for introducing a flow of fluid into the inner sheath so that the flow of fluid passes through the slot so as to provide a layer of fluid between the cap and the bearing portion of the spindle.

6. The intravascular blood pump according to claim 5 wherein the fluid connection between the interior lumen and the slot is a cut-down portion adjacent the distal end of the bearing portion.

7. The intravascular blood pump according to claim 1 further comprising:

an inflatable balloon mounted on the outer sheath adjacent the pump mechanism; and

means for inflating the balloon.

8. A method of providing blood circulation for a surgical patient, comprising the steps of:

(a) providing an intravascular blood pump, comprising;

a cable assembly having;

an outer sheath;

an inner sheath partially enclosed within the outer sheath; and

a drive cable partially enclosed within the inner sheath; and

a pump mechanism comprising

an outer sleeve having a first port therein and being attached to the outer sheath;

an inner sleeve in sliding engagement with the outer sleeve, the inner sleeve being attached to the inner sheath and at least partly defining a second port distally located relative to the first port; and

an impeller mounted within the inner sleeve, the impeller being attached to the drive cable;

the pump mechanism being movable between a retracted position wherein at least one of the first and second ports is sealed by one of the inner and outer sleeves, and an extended position wherein the first and second ports are open to permit fluid communication with the impeller;

(b) making an incision at the apex of the heart;

(c) while maintaining the intravascular blood pump in its retracted position to close at least one of the first and second ports, inserting the blood pump through the incision;

(d) placing the intravascular blood pump in it extended position and causing a portion of the inner sleeve to pass through one of the heart valves so that the second port is on the opposite side of the heart valve relative to the first port; and

(e) rotating the drive cable to thereby rotate the impeller to circulate blood.

9. The method according to claim 8 further comprising the step of locking the pump mechanism in the extended position.

10. The method according to claim 8 wherein the both the first and second ports are closed when the pump mechanism is in its retracted position.

11. The method according to claim 8 wherein the intravascular blood pump further comprises an inflatable balloon mounted on the outer sheath adjacent the pump mechanism;

the intravascular blood pump is inserted through the incision with the balloon a deflated condition;

the method further comprises the steps of

inflating the balloon after the inserting of the intravascular blood pump; and

withdrawing the cable assembly sufficiently to bring the balloon in contact with the inner wall of the heart.

12. An intravascular blood pump, comprising:

a driver; and

a pump mechanism comprising;

inner and outer sleeves in sliding interengagement, one of the inner and outer sleeves including a port, and the other of the inner and outer sleeves being movable relative to the port between a first position sealing the port and a second position wherein the port is open;

an impeller mounted within at least one of the inner and outer sleeves the impeller being operatively connected to the driver to rotate the impeller to pump fluid through the port; and

a controller operatively connected to the inner and outer sleeves to move them between the first and second positions.

13. The intravascular blood pump according to claim 12, wherein the driver comprises a drive cable, and the controller comprises at least one sheath enclosing the drive cable.

14. The intravascular blood pump according to claim 13 wherein the sheath is an inner sheath and wherein the controller further comprises an outer sheath, so that the inner sheath is partially enclosed within the outer sheath.

15. The intravascular blood pump according to claim 14 further comprising a locking mechanism attached to one of the inner sheath or the outer sheath and adapted to engage the other sheath for locking the pump mechanism in the second position.

16. The intravascular blood pump according to claim 14 wherein the inner sleeve further comprises:

a support member on the proximal side of the impeller, the inner sheath being attached to the support member

a distal member adjacent the impeller on the distal side of the impeller.

17. The intravascular blood pump according to claim 16 wherein the port constitutes a first port, the pump mechanism further having a second port adjacent the distal member that is open when the pump mechanism is in the second position and is closed when the pump mechanism is in the first position.

18. The intravascular blood pump according to claim 16 wherein

the inner sheath is attached to the support member by means of a spindle, the spindle having an interior lumen, a flange and a bearing portion, the bearing portion having at least one slot and at least one fluid connection between the interior lumen and the slot;

the impeller comprises a cap attached to the drive cable, the cap having a flange disposed adjacent the flange on the spindle; and

the blood pump further comprising means for introducing a flow of fluid into the inner sheath so that the flow of fluid passes through the slot so as to provide a layer of fluid between the cap and the bearing portion of the spindle.

19. The intravascular blood pump according to claim 18 wherein the fluid connection between the interior lumen and the slot is a cut-down portion adjacent the distal end of the bearing portion.

20. The intravascular blood pump according to claim 12 further comprising an inflatable balloon mounted on the outer sheath near the pump mechanism, and means for inflating the balloon.

21. An intravascular blood pump adapted to be inserted into a heart via the apex of the heart, the blood pump comprising:

a cable assembly having;

an outer sheath;

an inner sheath partially enclosed within the outer sheath; and

a drive cable partially enclosed within the inner sheath; and

a pump mechanism comprising;

an inner sleeve operatively connected to the inner sheath;

a distal member operatively connected to the inner sleeve and/or the inner sheath;

an outer sleeve having an inlet port therein, the outer sleeve being in sliding engagement with the inner sleeve and operatively connected to the outer sheath such that axial movement of the outer sheath relative to the inner sheath moves the outer sleeve axially relative to the inner sleeve between

a closed position in which the inlet port is sealed by the inner sleeve and the outer sleeve sealingly engages the distal member; and

an open position in which the inlet port is not sealed by the inner sleeve and the outer sleeve is spaced from the distal member to define an outlet port between the distal member and the outer sleeve; and

an impeller mounted within at least one of the inner and outer sleeves, the impeller being operatively connected to the drive cable so that the impeller is rotated when the drive cable rotates.

22. The intravascular blood pump according to claim 21 further comprising a locking mechanism attached to one of the inner sheath or the outer sheath and adapted to engage the other sheath for locking the pump mechanism in the open position.

23. The intravascular blood pump according to claim 21 wherein the inner sleeve further comprises a support member and the inner sheath is attached to the support member.

24. The intravascular blood pump according to claim 23 wherein

the inner sheath is attached to the support member by means of a spindle, the spindle having an interior lumen, a flange and a bearing portion, the bearing portion having at least one slot and at least one fluid connection between the interior lumen and the slot, and wherein

the impeller comprises a cap attached to the drive cable, the cap having a flange disposed adjacent but not contacting the flange on the spindle.

25. The intravascular blood pump according to claim 24 further comprising means for introducing a flow of fluid into the inner sheath so that the flow of fluid passes through the slot so as to provide a layer of fluid between the cap and the bearing portion of the spindle.

26. The intravascular blood pump according to claim 21 further comprising an inflatable balloon mounted on the outer sheath near the pump mechanism, and means for inflating the balloon.

27. An intravascular blood pump comprising:

a sheath having a flange, the sheath comprising;

an internal lumen;

a bearing portion generally adjacent the flange, the bearing having;

an end;

at least one slot extending substantially between the flange and the end; and

at least one channel along the end of the bearing portion providing fluid communication between the internal lumen and the slot;

a drive cable partially enclosed within the internal lumen of the sheath;

an impeller mounted on the drive cable so that the impeller is rotated when the drive cable rotates, the impeller having a cap receiving the bearing portion of the sheath, the cap slideably engaging the end of the bearing portion for rotation relative to the bearing portion, the cap having a flange disposed adjacent but not contacting the flange of the sheath to form a gap permitting the escape of fluid from the layer of fluid between the cap and bearing portion to purge the gap of blood; and

means for introducing a flow of fluid into the lumen of the sheath so that the flow of fluid passes through the slot to provide a layer of fluid between the cap and the bearing portion.

28. The intravascular blood pump according to claim 27 wherein the slot comprises a plurality of longitudinally extending slots substantially equally spaced apart along the bearing portion and the channel comprises a plurality of channels along the end of the bearing portion providing fluid communication between the internal lumen and plurality of slots.

29. The intravascular blood pump according to claim 27 wherein the pump includes a proximal inlet and distal outlet, and the force of blood being pumped by the impeller tends to drive the cap toward the end of the bearing portion.

30. An intravascular blood pump comprising:

a pump housing having a central axis, and an inlet and an outlet defining upstream and downstream directions;

an inlet flow straightener within the housing downstream of the inlet for aligning blood entering the pump housing via the inlet with the central axis;

an impeller within the housing downstream of the inlet flow straightener, the impeller being mounted for rotation to pump blood from the inlet to the outlet; and

an outlet flow straightener within the housing downstream of the impeller, the outlet flow straightener including vanes extending substantially from the impeller substantially to the outlet, the vanes curving from a relatively radial orientation with respect to the central axis to a relatively axial orientation with respect to the central axis to decrease the circumferential component of the velocity of the blood before the blood exists the outlet;

wherein the pump housing is generally cylindrical, the outlet extends generally circumferentially around the pump housing, and the pump housing forms a generally conical or frustoconical structure adjacent the outlet opening to encourage radially outward flow of blood through the outlet.

31. The blood pump according to claim 30 wherein the inlet comprises a plurality of inlet openings spaced radially apart along the pump housing.

32. The blood pump according to claim 31 further comprising a drive cable operatively connected to the impeller to rotate the impeller, the inlet flow straightener including a passageway through which the drive cable extends to operatively connect to the impeller.