Implantable heart assist system and method of applying same

• US 6,387,037 B1
• Filed: 12/23/1999
• Issued: 05/14/2002
• Est. Priority Date: 10/09/1997
• Status: Expired due to Term

• Current Assignee: TC1 LLC (Abbott Laboratories Incorporated), Thoratec LLC
• Original Assignee: ORQIS Medical Corporation
• Inventors: Viole, Anthony J., Gharib, Morteza, Bolling, Steven F., Gaddis, Mary Lynn, Aldea, Gabriel
• Primary Examiner(s): LAYNO, CARL HERNANDZ
• Application Number:
  US09/470,841
• Time in Patent Office: 873 Days
• Field of Search: 600/16, 600/17
• US Class Current: 600/16
• CPC Class Codes: A61M 1/3621 Extra-corporeal blood circuits single-needle circuits A61M1/30
• CPC Class Codes: A61M 1/3623 Means for actively controlling temperature of blood
• CPC Class Codes: A61M 1/3655 Arterio-venous shunts or fistulae
• CPC Class Codes: A61M 25/0026 Multi-lumen catheters with stationary elements catheter assemblies comprising a catheter in combination with a guide tube, sheath or sleeve A61M2025/0681; catheters comprising telescoping coaxial elements A61M2025/0175
• CPC Class Codes: A61M 25/007 Side holes, e.g. their profiles or arrangements; Provisions to keep side holes unblocked
• CPC Class Codes: A61M 60/117 for assisting the heart, e.g. transcutaneous or external ventricular assist devices
• 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 60/152 branching on and drawing blood from a blood vessel
• CPC Class Codes: A61M 60/165 implantable in, on, or around the heart
• CPC Class Codes: A61M 60/232 Centrifugal pumps
• CPC Class Codes: A61M 60/237 the blood flow through the rotating member having mainly axial components, e.g. axial flow pumps
• CPC Class Codes: A61M 60/274 the inlet and outlet being the same, e.g. para-aortic counter-pulsation blood pumps
• CPC Class Codes: A61M 60/31 for enhancement of in vivo organ perfusion, e.g. retroperfusion
• CPC Class Codes: A61M 60/408 the force acting on the blood contacting member being mechanical, e.g. transmitted by a shaft or cable
• CPC Class Codes: A61M 60/515 Regulation using real-time patient data
• CPC Class Codes: A61M 60/538 Regulation using real-time blood pump operational parameter data, e.g. motor current
• CPC Class Codes: A61M 60/876 Implantable batteries

Abstract

An extracardiac pumping system and method for using it supplement the circulation of blood, including the cardiac output, in a patient without any component thereof being connected to the patient'"'"'s heart. A battery powered pump may be implanted subcutaneously and attached to an inflow conduit fluidly coupled to a patient'"'"'s femoral artery via a subcutaneous anastomosis connection. The pump draws blood from the inflow conduit and discharges it through an outflow conduit fluidly coupled to a second peripheral artery via another subcutaneous anastomosis connection. The battery may be charged extracorporeally and the pump may be operated in either a continuous or pulsatile fashion in synchronization with the patient'"'"'s heart. The conduits can be housed in a multi-lumen catheter and a reservoir may be provided which fluidly communicates with the inflow conduits. An additional feature may keep blood traveling extracorporeally within the system at or near body temperature. The system is capable of adjusting outflow from the pump to optimize the mixing of red blood cells in the aorta and thereby enhance oxygen delivery to tissues by minimizing blood cell concentration in the center of the aorta.

Claims

1. An extracardiac pumping system for supplementing blood circulation in a patient without any component thereof being connected to the patient'"'"'s heart, the extracardiac system comprising:

a pump configured to pump blood through the patient at subcardiac flow rates, said pump having an average flow rate that, during normal operation thereof, is substantially below that of the patient'"'"'s heart when healthy;

an inflow conduit fluidly coupled to the pump to direct blood to the pump from a first blood vessel branching off from a blood vessel attached to the patient'"'"'s heart, the inflow conduit having a first end sized and configured to couple to the first blood vessel; and

a reservoir fluidly coupled to the inflow conduit, said reservoir being adapted to house a volume of blood from which the pump may draw blood.

2. An extracardiac pumping system for supplementing blood circulation in a patient without any component thereof being connected to the patient'"'"'s heart, the extracardiac system comprising:

a pump configured to pump blood through the patient at subcardiac flow rates, said pump having an average flow rate that, during normal operation thereof, is substantially below that of the patient'"'"'s heart when healthy;

an inflow conduit fluidly coupled to the pump to direct blood to the pump from a first blood vessel;

an outflow conduit fluidly coupled to the pump to direct blood from the pump to a second blood vessel; and

a multi-lumen catheter housing at least two lumens, a first lumen fluidly connected to the inflow conduit and a second lumen fluidly connected to the outflow conduit, at least one lumen also fluidly connected to a blood vessel branching off from a blood vessel connected to the patient'"'"'s heart;

whereby the system is applied to the patient at a single site and whereby blood may flow from the first blood vessel through the first lumen in the multi-lumen catheter into the inflow conduit and where blood may flow from the pump through the outflow conduit into the second lumen and into the second blood vessel.

3. A method of supplementing blood circulation in a patient using an extracardiac system comprising a pump, an inflow conduit and an outflow conduit, said method of using the extracardiac system not involving connecting any component of the extracardiac system to the patient'"'"'s heart, the method comprising the steps of:

inserting a multi-lumen catheter into the patient at a first blood vessel branching off from a blood vessel that is connected to the patient'"'"'s heart, the multi-lumen catheter housing at least two lumens, a first lumen in fluid communication with the first blood vessel and the inflow conduit, a second lumen fluidly connected to a second blood vessel and the outflow conduit, said inflow and outflow conduits being fluidly coupled to the pump;

withdrawing blood from the first blood vessel at subcardiac flow rates; and

delivering blood from the pump through the outflow conduit to the second blood vessel.

4. The method of claim 3 wherein the first blood vessel from which blood is withdrawn is from the group consisting of subclavian, axillary, femoral and carotid arteries.

5. An extracardiac pumping system for supplementing blood circulation in a patient without any component thereof being connected to the patient'"'"'s heart, the extracardiac system comprising:

a pump configured to pump blood through the patient at subcardiac flow rates, said pump having an average flow rate that, during normal operation thereof, is substantially below that of the patient'"'"'s heart when healthy;

an inflow conduit fluidly coupled to the pump to direct blood to the pump from a peripheral blood vessel, the inflow conduit having a first end comprising an intake port, the first end further comprising a wall having at least one hole therein to permit the passage of blood from the intake port through said hole; and

an outflow conduit fluidly coupled to the pump to direct blood from the pump to a second blood vessel.

6. An extracardiac pumping system for supplementing blood circulation in a patient without any component thereof being connected to the patient'"'"'s heart, the extracardiac system comprising:

a pump configured to pump blood through the patient at subcardiac flow rates, said pump having an average flow rate that, during normal operation thereof, is substantially below that of the patient'"'"'s heart when healthy;

an inflow conduit fluidly coupled to the pump to direct blood to the pump from a first blood vessel,

an outflow conduit fluidly coupled to the pump to direct blood from the pump to a peripheral blood vessel, the outflow conduit having a first end comprising an outlet port, the first end further comprising a wall having at least one hole therein to permit the passage of blood through said hole.

7. An extracardiac pumping system for supplementing blood circulation in a patient without any component thereof being connected to the patient'"'"'s heart, the extracardiac system comprising:

a pump configured to pump blood through the patient at subcardiac flow rates, said pump having an average flow rate that, during normal operation thereof, is substantially below that of the patient'"'"'s heart when healthy;

an inflow conduit fluidly coupled to the pump to direct blood to the pump from a first peripheral blood vessel, the inflow conduit having a first end sized and configured to couple to the first peripheral blood vessel;

an outflow conduit fluidly coupled to the pump to direct blood from the pump to a second blood vessel; and

means for minimizing heat loss from the blood that flows through the system.

8. A method for improving cross-sectional distribution of blood cells within a portion of the vascular system of a patient, the method comprising the steps of:

supplementing the patient'"'"'s cardiac output, said supplementing step comprising communicating blood at subcardiac rates between a peripheral blood vessel to a different blood vessel using an extracardiac system that does not have any component thereof being connected to the patient'"'"'s heart, said system including a pump;

assessing flow characteristics in a portion of the patient'"'"'s vascular system, and

adjusting the output of the pump to foster turbulent blood flow downstream of the heart.

9. The method of claim 8 wherein the step of assessing flow characteristics comprises determining the Reynolds number (N_R) for the flow through a portion of the patient'"'"'s vascular system, said determining step comprising the steps of:

measuring the diameter (d) of at least one blood vessel;

determining the viscosity (ν

) of the blood flowing through said vessel; and

determining the velocity (V) of the blood flowing through said vessel;

whereby N_R may be determined by the following equation;

$N_R=\frac{V·<br><br>d}{\mathrm{\upsilon <br><br>}}.$

10. The method of claim 9 wherein the step of determining the velocity of the blood flow is performed when said flow is being provided both by the patient'"'"'s heart output and the pump supplementing the patient'"'"'s heart.

11. The method of claim 9, wherein the step of adjusting the pump comprises varying the discharge of the pump so that the peak Reynolds number for the flow through the portion of the patient'"'"'s vascular system being assessed is at least approximately 2300.

12. The method of claim 11, wherein the peak Reynolds number is 2300 when the corresponding Womersley number for the flow is above about 5.

13. The method of claim 8, wherein the portion of the vascular system being assessed is the aorta.

14. A method for supplementing the circulation of blood in a patient while minimizing blood cell concentration at the center of a blood vessel in the patient'"'"'s circulatory system, said method using an extracardiac heart assist system without connecting any component of the system to the patient'"'"'s heart, the method comprising the steps of:

connecting a distal end of an inflow conduit to a first blood vessel to permit the flow of blood to a pump from the first blood vessel;

connecting a distal end of an outflow conduit to a second blood vessel to permit the flow of blood away from the pump to the second blood vessel;

operating the pump to perfuse blood through the patient'"'"'s circulatory system at subcardiac rates;

determining the velocity of blood flowing in the patient'"'"'s aorta; and

adjusting the pump output accordingly.

15. The method of claim 14 wherein the step of operating the pump is performed prior to the step of determining the velocity of blood flow.

16. The method of claim 14 wherein the step of connecting a distal end of either the inflow or outflow conduit to a blood vessel comprises connecting to a blood vessel that branches off from a blood vessel directly connected to the patient'"'"'s heart.

17. An extracardiac pumping system for supplementing blood circulation in a patient without any component thereof being connected to the patient'"'"'s heart, the extracardiac system comprising:

a pump configured to pump blood through the patient at subcardiac flow rates, said pump having an average flow rate that, during normal operation thereof, is substantially below that of the patient'"'"'s heart when healthy;

an inflow conduit fluidly coupled to the pump to direct blood to the pump from a first blood vessel that branches off from a blood vessel directly connected to the heart, the inflow conduit having a first end sized and configured to couple to the first blood vessel; and

an outflow conduit fluidly coupled to the pump to direct blood from the pump to a second blood vessel that branches off from a blood vessel directly connected to the heart, the outflow conduit having a first end sized and configured to couple to the second blood vessel.

18. The extracardiac pumping system of claim 17 further comprising means for portably carrying a portion of the extracardiac system that resides extracorporeally on the patient, the carrying means configured to carry at least the pump of said system.