Apparatus and method for selective separation of blood cholesterol

• US 5,152,743 A
• Filed: 08/20/1990
• Issued: 10/06/1992
• Est. Priority Date: 08/05/1988
• Status: Expired due to Term

• Current Assignee: Matria Healthcare, Inc. (Abbott Laboratories Incorporated)
• Original Assignee: Healthdyne, Inc. (Abbott Laboratories Incorporated)
• Inventors: Gorsuch, Reynolds G. F., Atkin, John
• Primary Examiner(s): Green, Randall L.
• Assistant Examiner(s): CLARKE, ROBERT A
• Application Number:
  US07/570,029
• Time in Patent Office: 778 Days
• Field of Search: 604/4-7, 604/48, 604/52, 604/53, 604/20, 604/29, 604/405, 604/406, 210/645, 210/646, 422/48
• US Class Current: 604/6.09
• CPC Class Codes: A61B 5/14528 invasively
• CPC Class Codes: A61B 5/14557 specially adapted to extracorporeal circuits
• CPC Class Codes: A61M 1/1678 intracorporal peritoneal dialysis A61M1/28
• CPC Class Codes: A61M 1/34 Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
• CPC Class Codes: A61M 1/3403 Regulation parameters
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/3553 remote, e.g. between patient's home and doctor's office
• CPC Class Codes: A61M 2205/3584 using modem, internet or bluetooth

Abstract

Selective separation of blood cholesterol by cascade filtration. An in vivo filter is implanted within a blood vessel to separate plasma from blood, and the separated plasma is removed to an extracorporeal secondary filter which removes low density lipoprotein (LDL) from the plasma. The in vivo portion of the apparatus comprises a number of microporous hollow fibers sized to permit diffusion of plasma, but not cellular or other larger blood components, through the fiber pores to the hollow interior of the fibers. The secondary filter passes the removed plasma along membrane walls formed by fibers sized to block passage of LDL while permitting passage of other plasma components, so that approximately 95 percent of LDL is separated from the plasma before the plasma is returned to the body in real time after removing the LDL cholesterol.

Claims

1. An apparatus using in vivo separation of plasma from blood for selective separation of blood cholesterol, comprising:

at least one elongated microporous fiber having a hollow interior, said fiber being dimensioned to be received within a blood vessel without significantly obstructing fluid flow through said blood vessel, the pore size of the fiber being sufficient to allow plasma to diffuse through the pores into the hollow interior of the fiber but not sufficient to allow cellular components larger than plasma to diffuse therethrough;

the hollow interior of said elongated fiber being in fluid communication with a means for conducting plasma comprising a first hollow tube which connects to the hollow interior of the fiber and permits passage of plasma from the fiber, and a second hollow tube which returns plasma to said blood vessel;

extracorporeal filter means receiving the plasma passing through the first tube and removing low density lipoproteins from the plasma; and

means conducting the plasma from the extracorporeal filter means to the second hollow tube for return to the blood vessel.

2. Apparatus as in claim 1, wherein the last-mentioned means comprises a pump for moving the plasma from the extracorporeal filter means to the second hollow tube.

3. Apparatus as in claim 1, wherein the fiber is composed of a polymeric material having a pore size of from about 0.1 to 1.0 μ

m.

4. Apparatus as in claim 1, wherein the fiber is composed of a polymeric material having a pore size of about 0.2 to 0.8 μ

m.

5. Apparatus as in claim 1, wherein the fiber is composed of a polymeric material having a pore size of about 0.4 to 0.6 μ

m.

6. Apparatus as in claim 1, wherein the extracorporeal filter means comprises at least one hollow fiber of polymeric material having pore size sufficient to allow the low density lipoprotein in the plasma to diffuse through the pores but not sufficient to allow plasma components larger than low density lipoprotein to diffuse therethrough.

7. Apparatus as in claim 4, wherein the fiber of the extracorporeal filter means has a pore size of about 0.003 to 0.004 μ

m.

8. An apparatus using in vivo separation of plasma from blood for separation of blood cholesterol, comprising:

at least one elongated microporous fiber having a hollow interior and dimensioned to fit within a blood vessel;

the pore size of the fiber being sufficient to allow plasma to diffuse through the pores into the hollow interior but not sufficient to allow cellular components larger than plasma to diffuse therethrough;

a header connected in fluid flow communication with the interior of the fiber;

a first hollow tube connected to the header to receive the plasma from the interior of the fiber;

extracorporeal means receiving the plasma passing through the first tube and operative to remove low density lipoprotein from the plasma;

a second hollow tube connected to the header and receiving the plasma from the extracorporeal means; and

a pump operative to return the plasma, after the removal of low density lipoprotein therefrom, through the second hollow tube to the header for return to the blood vessel.

9. The apparatus as in claim 8, wherein the microporous fiber has a pore size of about 0.1 to 1.0 μ

m.

10. A method using in vivo separation of plasma from blood for selective separation of blood cholesterol, comprising the steps of:

implanting in a blood vessel at least one elongated microporous fiber having a hollow interior and dimensioned for placement within a blood vessel without significantly obstructing fluid flow through the blood vessel, the pore size of the elongated microporous fiber being sufficient to allow plasma to diffuse through the pores into the hollow interior of the fiber but not sufficient to allow cellular components larger than plasma to diffuse therethrough;

placing the hollow interior of said elongated fiber in fluid communication with a first hollow tube which permits passage of plasma from the fiber;

removing plasma from the blood vessel through the first hollow tube;

treating the removed plasma to remove low-density lipoprotein from the plasma; and

then

re-infusing the plasma into the blood vessel.

11. A method for selective removal of blood cholesterol from a patient, comprising the steps of:

separating plasma in vivo within a blood vessel of the patient from cellular components larger than plasma of blood therein;

removing the separated plasma from the blood vessel and extracorporeally treating the removed plasma to remove low density lipoprotein from the plasma; and

then

reinfusing the plasma into the blood vessel.