Systems and methods for evaluating hemodialysis arteriovenous fistula maturation

Patent metadata

Field	Value
Publication number	US-11234649-B2
Application number	US-201916293496-A
Country	US
Kind code	B2
Filing date	Mar 5, 2019
Priority date	Jan 14, 2014
Publication date	Feb 1, 2022
Grant date	Feb 1, 2022

Abstract

The invention relates to evaluation of maturity of arteriovenous (AV) fistula using guidewires that measure intravascular blood flow and/or pressure. The invention provides methods of evaluating AV fistula maturation using an instrumented guidewire to measure intravascular flow and/or pressure. By using a small diameter guidewire that does not interfere substantially with the flow, an accurate measurement can be made that is useful for identifying when a fistula is mature and therefore ready to be used for hemodialysis. The flow of blood through the fistula is measured using the guidewire and the measured flow and/or pressure of blood is used to determine if the fistula is mature.

First claim

What is claimed is:

1. A tangible, non-transient computer readable medium comprising microprocessor executable instructions that, when executed, perform operations comprising:
receiving, from a flow sensor, a first flow rate measurement of blood through a fistula in fluid communication with a vessel;
receiving, from a pressure sensor, a first pressure measurement of blood adjacent the fistula;
determining, using the first flow rate measurement and the first pressure measurement, whether a therapy to the fistula is indicated;
providing a result indicative of a need to apply therapy to the fistula;
after determining whether the therapy to the fistula is indicated, receiving a second flow rate measurement of blood through the fistula and a second pressure measurement of blood adjacent the fistula; and
determining, using the second flow rate measurement and the second pressure measurement, whether further therapy to the fistula is indicated.

2. The tangible, non-transient computer readable medium of claim 1 , wherein the microprocessor executable instructions for determining, using the first flow rate measurement and the first pressure measurement, whether a therapy to the fistula is indicated comprises comparing the first flow rate measurement to a predetermined flow rate.

3. The tangible, non-transient computer readable medium of claim 2 , whereupon the first flow rate measurement equal to or greater than the predetermined flow rate, the therapy is indicated.

4. The tangible, non-transient computer readable medium of claim 3 , wherein the predetermined flow rate is 600 mL/min.

5. The tangible, non-transient computer readable medium of claim 1 , wherein the microprocessor executable instructions for determining, using the first flow rate measurement and the first pressure measurement, whether a therapy to the fistula is indicated comprises determining whether the fistula is mature.

6. The tangible, non-transient computer readable medium of claim 1 , wherein the microprocessor executable instructions for determining, using the first flow rate measurement and the first pressure measurement, whether a therapy to the fistula is indicated comprises determining a level of maturation of the fistula.

7. The tangible, non-transient computer readable medium of claim 6 , wherein determining the level of maturation of the fistula is based upon whether the first flow rate measurement is equal to or greater than a predetermined flow rate.

8. The tangible, non-transient computer readable medium of claim 7 , wherein the predetermined flow rate of blood is 600 mL/min.

9. The tangible, non-transient computer readable medium of claim 6 , wherein determining the level of maturation of the fistula is based upon whether the first pressure measurement is greater than a predetermined pressure.

10. The tangible, non-transient computer readable medium of claim 9 , wherein the first pressure measurement is indicative of a fractional flow reserve.

11. The tangible, non-transient computer readable medium of claim 10 , wherein the predetermined pressure is 0.80.

12. The tangible, non-transient computer readable medium of claim 7 , wherein determining a level of maturation of the fistula is based upon whether the first pressure measurement is greater than a predetermined pressure.

13. The tangible, non-transient computer readable medium of claim 12 , wherein the first pressure measurement is indicative of a fractional flow reserve.

14. The tangible, non-transient computer readable medium of claim 13 , wherein the predetermined pressure is 0.80.

15. The tangible, non-transient computer readable medium of claim 1 , wherein the microprocessor executable instructions for determining, using the first flow rate measurement and the first pressure measurement, whether a therapy to the fistula is indicated comprises comparing the first pressure measurement to a predetermined pressure.

16. The tangible, non-transient computer readable medium of claim 15 , whereupon the first pressure measurement being greater than the predetermined pressure, the therapy is indicated.

17. The tangible, non-transient computer readable medium of claim 16 , wherein the predetermined pressure is 0.80.

18. A system for assessing a fistula, the system comprising:
a guidewire comprising a flow sensor and a pressure sensor; and
a computer communicatively coupled to the guidewire, wherein the computer comprises a memory and executable instructions stored in the memory, whereupon being executed, the executable instructions perform operations comprising:
receiving, from the flow sensor, a first flow rate measurement of blood through a fistula in fluid communication with a vessel;
receiving, from the pressure sensor, a first pressure measurement of blood adjacent the fistula;
determining, using the first flow rate measurement and the first pressure measurement, whether a therapy to the fistula is indicated;
providing a result indicative of a need to apply therapy to the fistula;
receiving a second flow rate measurement of blood through the fistula and a second pressure measurement of blood adjacent the fistula; and
determining, using the second flow rate measurement and the second pressure measurement, whether further therapy to the fistula is indicated.

19. The system of claim 18 , wherein the microprocessor executable instructions for determining, using the first flow rate measurement and the first pressure measurement, whether the therapy to the fistula is indicated comprises comparing the first flow rate measurement to a predetermined flow rate and comparing the first pressure measurement to a predetermined pressure.

20. The system of claim 19 , whereupon the first flow rate measurement being equal to or greater than the predetermined flow rate and the first pressure measurement being equal greater than the predetermined pressure, the therapy is indicated.

Assignees

• Volcano Corp
• Philips Image Guided Therapy Corp

Inventors

• Matsubara Bradley S
• Unser John

Classifications

• A61M2025/09083

  having a coil around a core · CPC title

• A61M2025/09175

  having specific characteristics at the distal tip · CPC title

• A61M25/09

  Guide wires · CPC title

• A61B8/06

  Measuring blood flow · CPC title

• A61B5/0265

  using electromagnetic means, e.g. electromagnetic flowmeter · CPC title