Drive mechanism for powering intravascular blood pumps

• US 4,895,557 A
• Filed: 12/07/1987
• Issued: 01/23/1990
• Est. Priority Date: 12/07/1987
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Nimbus Medical, Inc. (Thoratec LLC)
• Inventors: Carriker, John W., Moise, John C., Baxter, Reginald R.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Lewis, Ralph
• Application Number:
  US07/129,714
• Time in Patent Office: 778 Days
• Field of Search: 128/1 D, 128/305, 128/DIG. 3, 604/22, 604/151, 604/267, 623/3, 415/DIG. 4, 415/213 C, 417/352-354, 310/54, 600/16-18
• US Class Current: 600/16
• CPC Class Codes: A61M 60/13 by means of a catheter allowing explantation, e.g. catheter pumps temporarily introduced via the vascular system
• CPC Class Codes: A61M 60/135 inside a blood vessel, e.g. using grafting
• 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 60/216 including a rotating member acting on the blood, e.g. impeller
• CPC Class Codes: A61M 60/279 Peristaltic pumps, e.g. roller pumps
• CPC Class Codes: A61M 60/414 transmitted by a rotating cable, e.g. for blood pumps mounted on a catheter
• CPC Class Codes: A61M 60/422 the force acting on the blood contacting member being electromagnetic, e.g. using canned motor pumps
• CPC Class Codes: A61M 60/462 Electromagnetic force
• 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 60/857 Implantable blood tubes
• CPC Class Codes: Y10S 415/90 Rotary blood pump

Abstract

A disposable, sterilizable cable drive unit for an intravascular blood pump includes a rotor enclosed in a fluid-tight enclosure which can be slipped into the stator of a drive motor. The unit is connectable to a constant-rate purge fluid supply and to a dual-lumen cable sheath. One lumen provides a sterile purge fluid path; the other carries the drive cable to the blood pump and provides a return path for a flushing fluid in which the cable is immersed. The flushing unit is derived from the purge fluid supply at a constant rate, and the rotor may also be immersed in it if desired. The unit is held in the drive motor by a manually operated detent, and the self-centering action of the rotor aligns it with the stator when the motor is energized. The motor is mounted on a gimbal so as to be alignable with the cable sheath at its point of insertion into the patient'"'"'s vascular system, in order to prevent stresses on the patient and kinks in the cable sheath.

Claims

1. A cable drive for an intravascular blood pump, comprising:

(a) a motor having a stator surrounding a hollow space; and

(b) a cable drive unit removably insertable into said hollow space, said cable drive unit including;

(i) fluid-tight housing means having a fluid inlet and a fluid outlet, and a fluid passage connecting the same;

(ii) rotor means disposed within said housing means, said rotor means being arranged to be rotated when said housing means is inserted into said stator and said stator is energized; and

(iii) means on said rotor means for receiving a drive cable extending though said fluid outlet.

2. A combined sterilizable drive and purge fluid supply system for an intravascular blood pump, comprising:

(a) a source of purge fluid;

(b) an intravascular blood pump;

(c) cable sheath means connected to said blood pump for conveying purge fluid to said blood pump;

(d) flexible cable means connected to said blood pump for driving said blood pump, said cable means being positioned in said cable sheath means longitudinally thereof;

(e) a drive motor stator surrounding a hollow space;

(f) a fluid-tight cable drive removably insertable into said hollow space said cable drive unit including

(i) a housing; and

(ii) rotor means rotatably supported within said housing, said rotor means being connected to said cable means to rotate the same;

(g) tubing means for conveying said purge fluid from said purge fluid source to said cable drive unit; and

(h) purge fluid pump means for pumping purge fluid through said tubing means, said tubing means, cable drive unit and cable sheath being interconnected so as to provide a continuous purge fluid flow path therethrough from said purge fluid source to said blood pump.

3. The system of claim 2, in which said cable sheath means include a pair of lumens, one of said lumens being conectable to said tubing means, and the other lumen containing said cable means and being connectable to fluid discharge means.

4. The system of claim 3, further comprising discharge pump means for pumping fluid through said other lumen toward said fluid discharge means.

5. The system of claim 4, in which said discharge pump means are of a type arranged to convey fluid at a constant rate toward said fluid discharge means.

6. The system of claim 3, in which said cable drive unit further includes a fluid passage through said housing, and said other lumen is connectable to said fluid discharge means through said fluid passage.

7. The system of claim 6, in which said rotor is positioned in said fluid passage.

8. The system of claim 7, in which said rotor is coated to prevent corrosion by the fluid in said fluid passage.

9. The system of claim 2, in which said stator is gimbaled so that its axis is substantially omnidirectionally movable.

10. The system of claim 2, in which the interconnection between said rotor means and said cable means is such as to permit free relative movement between said rotor means and said cable means in the axial direction but not in the rotary direction.

11. The system of claim 2, in which said purge fluid pump means are of a type arranged to convey fluid at a constant rate through said tubing.

12. A disposable, sterilizable intravascular axial flow blood pump assembly, comprising:

(a) a blood pump;

(b) a cable drive unit insertable into and removable from a hollow space formed by the stator of an elector motor without disassembly of said motor said cable drive unit including a rotor for said motor;

(c) a cable sheath connecting said blood pump and said cable drive unit in fluid tight relationship; and

(d) a flexible drive cable operatively connecting said motor rotor and the rotor of said blood pump;

(e) said drive cable extending through said cable sheath, and said cable sheath forming a fluid conduit for conveying fluid between said cable drive unit and said blood pump.

13. A disposable, sterilizable intravascular axial flow blood pump assembly, comprising:

(a) a blood pump;

(b) a cable drive unit removable insertable into a hollow space formed by the stator of an electric motor, said cable drive unit including a rotor for said motor;

(c) a cable sheath connecting said blood pump and said cable drive unit in fluid tight relationship; and

(d) a flexible drive cable operatively connecting said motor rotor and the rotor of said blood pump;

(e) said drive cable extending through said cable sheath, and said cable sheath forming a fluid conduit for conveying fluid between said cable drive unit and said blood pump; and

(f) said cable sheath having a pair of lumens, one of said lumens forming a fluid path for conveying purge fluid from said cable drive unit to said blood pump, the other of said lumens forming a fluid path for conveying flushing fluid from said blood pump to said cable drive unit, and said drive cable extending through said other lumen.

14. The assembly of claim 13, in which said lumens are substantially concentric.

15. The assembly of claim 13, further including means for diverting a portion of any fluid flowing through said one lumen toward said blood pump into said other lumen at said blood pump for returning it to said cable drive unit.