METHODS FOR DETERMINING FRACTIONAL FLOW RESERVE

• US 20110178417A1
• Filed: 09/22/2009
• Published: 07/21/2011
• Est. Priority Date: 09/22/2008
• Status: Active Grant

• Current Assignee: 3DT Holdings LLC
• Original Assignee: 3DT Holdings LLC
• Inventors: Kassab, Ghassan S.
• Granted Patent: US 8,702,613 B2
• Time in Patent Office: Days
• US Class Current: 600/486
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/02158 provided with two or more sensor elements
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/0275 using tracers, e.g. dye dilution
• CPC Class Codes: A61B 5/028 by thermo-dilution
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/6852 Catheters

Abstract

Devices, systems, and methods for determining fractional flow reserve. At least one method for determining fractional flow reserve of the present disclosure comprises the steps positioning a device comprising at least two sensors within a luminal organ at or near a stenosis, wherein the at least two sensors are separated a predetermined distance from one another, operating the device to determine flow velocity of a second fluid introduced into me luminal organ to temporarily displace a first fluid present within the luminal organ, and determining fractional flow reserve at or near the stenosis based upon the flow velocity, a mean aortic pressure within the luminal organ, and at least one cross-sectional area at or near the stenosis. Devices and systems useful for performing such exemplary methods are also disclosed herein.

Claims

1. A method for determining fractional flow reserve within a luminal organ, the method comprising the steps of:

positioning a device comprising at least two sensors within a luminal organ at or near a stenosis, wherein the at least two sensors are separated a predetermined distance from one another;

operating the device to determine flow velocity of a second fluid introduced into the luminal organ to temporarily displace a first fluid present within the luminal organ; and

determining fractional flow reserve at or near the stenosis based upon the flow velocity, a mean aortic pressure within the luminal organ, and at least one cross-sectional area at or near the stenosis.

2. The method of claim 1, wherein the at least one cross-sectional area comprises:

a cross-sectional area of the luminal organ distal to the stenosis;

a cross-sectional area of the luminal organ proximal to the stenosis; and

at least one cross-sectional area of the luminal organ at the stenosis.

3. The method of claim 1, wherein the step of determining fractional flow reserve is further based upon a determination of volumetric flow between the at least two sensors.

4. The method of claim 3, wherein the determination of volumetric flow is based upon the flow velocity and the at least one cross-sectional area.

5. The method of claim 1, wherein the step of operating the device to determine flow velocity of a fluid introduced into the luminal organ comprises the steps of:

detecting the first fluid within the luminal organ using at least one of the at least two sensors, wherein the first fluid has a first parameter having a first value;

introducing the second fluid into the luminal organ, said second fluid temporarily displacing the first fluid within the luminal organ at the site of introduction, wherein the second fluid has a second paramater having a second value, the second value differing from the first value;

detecting the second value of the second parameter of the second fluid by the at least two sensors;

measuring time of detection of the second value of the second parameter of the second fluid by each of the at least two sensors; and

determining flow velocity of the second fluid within the luminal organ based upon the time of detection of the second value of the second parameter of the second fluid by each of the at least two sensors.

6. The method of claim 5, wherein the first parameter and the second parameter are conductivity, pH, temperature, or an optically-detectable substance.

7. The method of claim 1, further comprising the step of diagnosing a disease based upon the determination of flow velocity within a luminal organ.

8. The method of claim 1, wherein the determination of fractional flow reserve is indicative of a degree of stenosis within the luminal organ.

9. The method of claim 1, wherein the step of determining fractional flow reserve is performed using a data acquisition and processing system.

10. The method of claim 1, wherein the first fluid comprises blood and wherein the second fluid comprises saline.

11. A method for determining fractional flow reserve within a luminal organ, the method comprising the steps of:

positioning a device comprising at least two sensors within a luminal organ at or near a stenosis, wherein the at least two sensors are separated a predetermined distance from one another;

detecting blood within the luminal organ using at least one of the at least two sensors, wherein the blood has a first parameter having a first value;

introducing a fluid into the luminal organ, said fluid temporarily displacing the blood within the luminal organ at the site of introduction, wherein the introduced fluid has a second parameter having a second value, the second value differing from the first value;

detecting the second value of the second parameter of the introduced fluid by the at least two sensors;

measuring time of detection of the second value of the second parameter of the introduced fluid by each of the at least two sensors;

determining flow velocity of the introduced fluid within the luminal organ based upon the time of detection of the second value of the parameter of the introduced fluid by each of the at least two sensors; and

determining fractional flow reserve at or near the stenosis based upon a mean aortic pressure within the luminal organ, a cross-sectional area of the luminal organ distal to the stenosis, a cross-sectional area of the luminal organ proximal to the stenosis, and at least one cross-sectional area of the luminal organ at the stenosis.

12. (canceled)

13. A method for determining fractional flow reserve within a luminal organ using impedance, the method comprising the steps of:

positioning a device comprising a pair of excitation electrodes and at least two pairs of detection electrodes within a luminal organ at or near a stenosis, wherein the at least two pairs of detection electrodes are separated a predetermined distance from each other;

operating the device to determine flow velocity of a second fluid introduced into the luminal organ, said second fluid temporarily displacing a first fluid present within the luminal organ; and

determining fractional flow reserve at or near the stenosis based upon the flow velocity, a mean aortic pressure within the luminal organ, and at least one cross-sectional area at or near the stenosis.

14. The method of claim 13, wherein the at least one cross-sectional area comprises:

a cross-sectional area of the luminal organ distal to the stenosis;

a cross-sectional area of the luminal organ proximal to the stenosis; and

at least one cross-sectional area of the luminal organ at the stenosis.

15. The method of claim 13, wherein the step of determining fractional flow reserve is further based upon a determination of volumetric flow between the at least two pairs of detection electrodes.

16. The method of claim 15, wherein the determination of volumetric flow is based upon the flow velocity and the at least one cross-sectional area.

17. The method of claim 13, wherein the step of operating the device to determine flow velocity of a fluid introduced into the luminal organ comprises the steps of:

activating the pair of excitation electrodes to generate a field detectable by the detection electrodes;

detecting conductance of the first fluid having a first conductivity within the luminal organ using at least one pair of the at least two pairs of detection electrodes;

introducing the second fluid having a second conductivity into the luminal organ, said second fluid temporarily displacing the first fluid within the luminal organ at the site of introduction, wherein the first conductivity does not equal the second conductivity;

detecting the conductance of the second fluid by the at least two pairs of detection electrodes;

measuring time of conductance detection of the second fluid by each of the at least two pairs of detection electrodes; and

determining flow velocity of the second fluid within the luminal organ based upon the time of conductance detection by each of the at least two pairs of detection electrodes.

18. The method of claim 13, wherein the step of operating the device to determine flow velocity of a fluid introduced into the luminal organ comprises the steps of:

activating the pair of excitation electrodes to generate a field;

detecting conductance of the first fluid having a first conductivity within the luminal organ using at least one pair of the at least two pairs of detection electrodes;

introducing the second fluid having a second conductivity into the luminal organ, said second fluid temporarily displacing the first fluid within the luminal organ at the site of introduction, wherein the first conductivity does not equal the second conductivity;

detecting the conductance of the second fluid by the at least two pairs of detection electrodes;

measuring time of conductance detection of the second fluid using at least one pair of the at least two pairs of detection electrodes; and

determining flow velocity of the second fluid within the luminal organ based upon the time of conductance detection using;

(a) a first excitation electrode of the pair of excitation electodes and a first pair of detection electrodes of the at least two pairs of detection electrodes, and

(b) a second excitation electrode of the pair of excitation electodes and a second pair of detection electrodes of the at least two pairs of detection electrodes.

19. The method of claim 13, further comprising the step of diagnosing a disease based upon the determination of flow velocity within a luminal organ.

20. The method of claim 13, wherein the determination of fractional flow reserve is indicative of a degree of stenosis within the luminal organ.

21. The method of claim 13, wherein the step of determining fractional flow reserve is performed using a data acquisition and processing system.

22. The method of claim 13, wherein the first fluid comprises blood and wherein the second fluid comprises saline.

23. A method for determining fractional flow reserve within a luminal organ using impedance, the method comprising the steps of:

positioning a device comprising a pair of excitation electrodes and at least two pairs of detection electrodes within a luminal organ at or near a stenosis, wherein the at least two pairs of detection electrodes are separated a predetermined distance from each other;

activating the pair of excitation electrodes to generate a field detectable by the detection electrodes;

detecting conductance of blood within the luminal organ using at least one pair of the at least two pairs of detection electrodes, wherein the blood has a first conductivity;

introducing a fluid having a second conductivity into the luminal organ, said fluid temporarily displacing the blood at the site of introduction, wherein the first conductivity does not equal the second conductivity;

detecting the conductance of the introduced fluid by the at least two pairs of detection electrodes;

measuring time of conductance detection of the introduced fluid by each of the at least two pairs of detection electrodes;

determining flow velocity of the introduced fluid within the luminal organ based upon the time of conductance detection by each of the at least two pairs of detection electrodes; and

determining fractional flow reserve at or near the stenosis based upon a mean aortic pressure within the luminal organ, a cross-sectional area of the luminal organ distal to the stenosis, a cross-sectional area of the luminal organ proximal to the stenosis, and at least one cross-sectional area of the luminal organ at the stenosis.

24-44. -44. (canceled)