System and method for measuring cross-sectional areas and pressure gradients in luminal organs

• US 20080033316A1
• Filed: 08/14/2007
• Published: 02/07/2008
• Est. Priority Date: 02/21/2003
• Status: Active Grant

• Current Assignee: Electro-Cat, LLC
• Original Assignee: Electro-Cat, LLC
• Inventors: Kassab, Ghassan, Movahed, Mohamed, Gregersen, Hans
• Granted Patent: US 8,114,143 B2
• Time in Patent Office: Days
• US Class Current: 600/547
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/036 by means introduced into body tracts A61B5/032 and A61B5/035 take precedence
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/1076 for measuring dimensions inside body cavities, e.g. using catheters A61B3/1005 takes precedence
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61M 25/10 Balloon catheters A61M25/0125 takes precedence; embolectomy A61B17/22032; retractors A61B17/02; inflatable balloons for placing stents or stent-grafts A61F2/958 ; stomach balloons for treatment of obesity A61F5/0003; oesophagal tubes A61J15/00

Abstract

The invention comprises a system, catheter and method for measuring the cross-sectional areas and pressure gradients in any hollow organ, such as, for example, blood vessels. One embodiment of such a system includes: an impedance catheter capable of being introduced into a targeted site; a solution delivery source; a constant current source; a balloon inflation control device; and a data acquisition and processing system that receives conductance and/or pressure gradient data from the catheter and calculates the cross-sectional area of the targeted site. In one embodiment, the catheter has an inflatable balloon along its longitudinal axis, thereby enabling the breakup of any materials causing stenosis at the targeted site and/or distention and delivery of an optional stent into the targeted site.

Claims

1. An impedance catheter for measuring luminal cross-sectional area of blood vessels, heart valves, and other hollow visceral organs, for enabling selection of an appropriately sized stent or other medical device and for avoiding under or over deployment and under or over sizing of the stent or other medical device, comprising:

an elongated tubular body extending from a proximal body end to a distal body end, said body having an exterior surface and defining a first lumen along the longitudinal axis of the body, whereby enabling introduction of the catheter into a treatment site;

a first excitation impedance electrode and a second excitation impedance electrode along the longitudinal axis of the body, both located near the distal body end, said first excitation electrode comprising a first excitation impedance lead extending from said first excitation electrode to a data acquisition system near the proximal body end, said second excitation electrode comprising a second excitation impedance lead extending from said second excitation electrode to the data acquisition system;

a first detection impedance electrode and a second detection impedance electrode along the longitudinal axis of the body, both located in between the first and second excitation electrodes, said first detection electrode comprising a first detection impedance lead extending from said first detection electrode to the data acquisition system, said second detection electrode comprising a second detection impedance lead extending from said second detection electrode to the data acquisition system; and

a first suction/infusion port located near the distal end, wherein said first suction/infusion port is in communication with said first lumen, whereby enabling injection of two or more solutions into the treatment site;

wherein at least one of the first and second excitation electrodes are in communication with a constant current source, whereby enabling supply of constant electrical current to the treatment site, whereby enabling measurement of two or more conductance values at the treatment site, and whereby enabling calculation of cross-sectional area at the treatment site.

2. A system for measuring luminal cross-sectional area of blood vessels, heart valves, and other hollow visceral organs, for enabling selection of an appropriately sized stent or other medical device and for avoiding under or over deployment and under or over sizing of the stent or other medical device, comprising:

an impedance catheter extending from a proximal catheter end to a distal catheter end, said catheter capable of being introduced into a treatment site, said catheter further comprising;

a suction/infusion port near the distal catheter end;

two or more excitation electrodes; and

two or more detection electrodes;

a solution delivery source for injecting a solution through the catheter, through the suction/infusion port and into the treatment site, whereby enabling injection of two or more solutions into the treatment site;

a constant current source in communication with at least one of the excitation electrodes, whereby enabling supply of constant electrical current to the treatment site; and

a data acquisition and processing system in communication with the detection electrodes, whereby enabling measurement of two or more conductance values at the treatment site, and whereby enabling calculation of cross-sectional area at the treatment site.

3. An impedance catheter, comprising:

an elongated tubular body extending from a proximal body end to a distal body end, said body having an exterior surface and defining a first lumen along the longitudinal axis of the body;

a first excitation impedance electrode and a second excitation impedance electrode along the longitudinal axis of the body, both located near the distal body end, said first excitation electrode comprising a first excitation impedance lead extending from said first excitation electrode to a data acquisition system near the proximal body end, said second excitation electrode comprising a second excitation impedance lead extending from said second excitation electrode to the data acquisition system;

a first detection impedance electrode and a second detection impedance electrode along the longitudinal axis of the body, both located in between the first and second excitation electrodes, said first detection electrode comprising a first detection impedance lead extending from said first detection electrode to the data acquisition system, said second detection electrode comprising a second detection impedance lead extending from said second detection electrode to the data acquisition system; and

a first suction/infusion port located near the distal end, wherein said first suction/infusion port is in communication with said first lumen.

4. The impedance catheter of claim 3, wherein the first lumen is in communication with a source of a solution to be injected through the first lumen, through the first suction/infusion port into a targeted treatment site.

5. The impedance catheter of claim 4, wherein the solution comprises an NaCl solution.

6. The impedance catheter of claim 3, further comprising a first pressure port along the longitudinal axis of the elongated body, located near the distal end, wherein said first pressure port is in communication with at least one pressure conduit, wherein said pressure conduit is in communication with a pressure transducer.

7. The impedance catheter of claim 3, further comprising:

a second lumen defined by the body and located along the longitudinal axis of the body; and

an inflatable balloon along the longitudinal axis of the elongated body, located near and proximal relative to the first suction/infusion port, wherein the inflatable balloon extends from a balloon proximal end to a balloon distal end, wherein the inflatable balloon is in communication with the second lumen.

8. The impedance catheter of claim 7, wherein the second lumen is in communication with a balloon inflation control device.

9. The impedance catheter of claim 7, further comprising:

a third excitation impedance electrode and a fourth excitation impedance electrode along the longitudinal axis, both located between the proximal balloon end and the distal balloon end, said third excitation electrode comprising a third excitation impedance lead extending from said third excitation electrode to the proximal body end, said fourth excitation electrode comprising a fourth excitation impedance lead extending from said fourth excitation electrode to the proximal body end; and

a third detection impedance electrode and a fourth detection impedance electrode along the longitudinal axis of the body, both located in between the third and fourth excitation electrodes, said third detection electrode comprising a third detection impedance lead extending from said third detection electrode to the proximal body end, said fourth detection electrode comprising a fourth detection impedance lead extending from said fourth detection electrode to the proximal body end.

10. The impedance catheter of claim 7, further comprising a second suction/infusion port located between the proximal balloon end and the distal balloon end, wherein said second suction/infusion port is in communication with said first lumen.

11. The impedance catheter of claim 3, further comprising an ultrasound transducer near the distal end of the elongated body.

12. The impedance catheter of claim 7, further comprising a stent located over the balloon, said stent capable of being distended and implanted into the treatment site.

13. A system for measuring a cross-sectional area of a targeted treatment site, comprising:

an impedance catheter extending from a proximal catheter end to a distal catheter end, said catheter further comprising a suction/infusion port near the distal catheter end;

a solution delivery source for injecting a solution through the catheter, through the suction/infusion port and into the treatment site;

a constant current source; and

a data acquisition and processing system that receives conductance data from the catheter and determines the cross-sectional area of the treatment site.

14. The system of claim 13, wherein the data acquisition processing system further comprises a processing unit.

15. The system of claim 13, wherein the data acquisition processing system further comprises a personal computer.

16. The system of claim 13, wherein the solution comprises an NaCl solution.

17. The system of claim 13, wherein the treatment site comprises a body lumen.

18. The system of claim 13, further comprising a fluid heating unit in communication with the fluid delivery source.

19. The system of claim 13, wherein the catheter further comprises an inflatable balloon along its longitudinal axis.

20. The system of claim 13, wherein the catheter further comprises a pressure transducer near the distal catheter end.

21. The system of claim 20, wherein the data acquisition and processing system receives pressure data from the pressure transducer and determines the cross-sectional area of the treatment site.

22. A method for constructing a three-dimensional model of a treatment site, comprising:

introducing an impedance catheter into the treatment site;

measuring a first cross-sectional area at a first point along the longitudinal axis;

pulling back the catheter to a second point along the longitudinal axis at a first speed, wherein the second point is located proximally relative to the first point along the longitudinal axis;

measuring a second cross-sectional area at the second point along the longitudinal axis; and

constructing a three-dimensional model of the treatment site along the longitudinal axis based in part on the first and second cross-sectional area measurements.

23. The method of claim 22, further comprising the steps of:

pulling back the catheter to a third point along the longitudinal axis at a second speed, wherein the third point is located proximally relative to the second point along the longitudinal axis, wherein the second speed is equal to the first speed;

measuring a third cross-sectional area at the third point along the longitudinal axis; and

constructing a three-dimensional model of the treatment site along the longitudinal axis based in part on the third cross-sectional area measurement.

24. The method of claim 22, wherein the treatment site comprises a body lumen.

25. The method of claim 24, wherein the body lumen comprises a blood vessel.

26. A method for constructing a three-dimensional model of a treatment site, comprising:

introducing an impedance catheter into the treatment site;

measuring a first cross-sectional area at a first point along the longitudinal axis;

pushing forward the catheter to a second point along the longitudinal axis at a first speed, wherein the second point is located distally relative to the first point along the longitudinal axis;

measuring a second cross-sectional area at the second point along the longitudinal axis; and

constructing a three-dimensional model of the treatment site along the longitudinal axis based in part on the first and second cross-sectional area measurements.

27. The method of claim 26, further comprising the steps of:

pushing forward the catheter to a third point along the longitudinal axis at a second speed, wherein the third point is located distally relative to the second point along the longitudinal axis, wherein the second speed is equal to the first speed;

measuring a third cross-sectional area at the third point along the longitudinal axis; and

constructing a three-dimensional model of the treatment site along the longitudinal axis based in part on the third cross-sectional area measurement.

28. The method of claim 26, wherein the treatment site comprises a body lumen.

29. The method of claim 28, wherein the body lumen comprises a blood vessel.

30. An impedance catheter assembly, comprising:

an elongate wire extending from a proximal wire end to a distal wire end;

a catheter comprising an elongate tube extending from a proximal tube end to a distal tube end, said tube having an exterior surface and defining a tube lumen along the longitudinal axis of the tube, said tube surrounding the wire coaxially;

a first excitation impedance electrode and a second excitation impedance electrode along the longitudinal axis of the wire, both located near the distal wire end, said first excitation electrode comprising a first excitation impedance lead extending from said first excitation electrode to a data acquisition system near the proximal wire end, said second excitation electrode comprising a second excitation impedance lead extending from said second excitation electrode to the data acquisition system; and

a first detection impedance electrode and a second detection impedance electrode along the longitudinal axis of the wire, both located in between the first and second excitation electrodes, said first detection electrode comprising a first detection impedance lead extending from said first detection electrode to the data acquisition system, said second detection electrode comprising a second detection impedance lead extending from said second detection electrode to the data acquisition system.

31. The assembly of claim 30, wherein the wire comprises a pressure wire.

32. The assembly of claim 30, wherein the catheter comprises a sensor for measurement of flow.

33. The assembly of claim 30, wherein the wire comprises a guide wire.

34. The assembly of claim 30, wherein the catheter comprises a guide catheter.

35. The assembly of claim 30, wherein the wire and catheter are dimensioned so that a first solution can be infused through the tube lumen.

36. The assembly of claim 35, wherein the first solution comprises an NaCl solution.

37. A system for measuring a cross-sectional area of a targeted treatment site, comprising:

an impedance catheter assembly;

a solution delivery source for injecting a solution through the assembly and into the treatment site;

a constant current source; and

a data acquisition and processing system that receives conductance data from the assembly and determines the cross-sectional area of the treatment site.

38. The system of claim 37, wherein the assembly comprises:

an elongate wire extending from a proximal wire end to a distal wire end;

a catheter comprising an elongate tube extending from a proximal tube end to a distal tube end, said tube having an exterior surface and defining a tube lumen along the longitudinal axis of the tube, said tube surrounding the wire coaxially;

a first excitation impedance electrode and a second excitation impedance electrode along the longitudinal axis of the wire, both located near the distal wire end, said first excitation electrode comprising a first excitation impedance lead extending from said first excitation electrode to a data acquisition system near the proximal wire end, said second excitation electrode comprising a second excitation impedance lead extending from said second excitation electrode to the data acquisition system; and

a first detection impedance electrode and a second detection impedance electrode along the longitudinal axis of the wire, both located in between the first and second excitation electrodes, said first detection electrode comprising a first detection impedance lead extending from said first detection electrode to the data acquisition system, said second detection electrode comprising a second detection impedance lead extending from said second detection electrode to the data acquisition system.