Catheter and method for calculating fractional flow reserve

Patent metadata

Field	Value
Publication number	US-11272850-B2
Application number	US-201715671686-A
Country	US
Kind code	B2
Filing date	Aug 8, 2017
Priority date	Aug 9, 2016
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

A catheter for measuring a fractional flow reserve includes a proximal shaft, a distal shaft coupled to a distal portion of the proximal shaft, and a pressure sensor coupled to the distal shaft. The distal shaft includes a middle wall portion configured to extend through a stenosis in a vessel. The middle wall portion of the distal shaft includes at least one skive reducing the cross-sectional profile of the middle wall portion. The middle wall portion may further include at least one stiffening wire for increasing columnar stiffness of the middle wall portion.

First claim

What is claimed is:

1. A catheter for measuring a fractional flow reserve, the catheter comprising:
a proximal shaft;
a distal shaft defining a guidewire lumen configured to receive a guidewire therein and including a proximal wall portion, a middle wall portion, and a distal wall portion;
a pressure sensor coupled to the distal wall portion of the distal shaft;
a skive in the middle wall portion configured to reduce a cross sectional area of the middle wall portion, extending longitudinally along an entire length of the middle wall portion configured to extend across an intra-stenosis lumen of a stenosis of a patient vessel, configured to extend around a majority of a circumference of the distal shaft in at least a portion of the middle wall portion, and extending radially through the middle wall portion exposing the guidewire lumen; and
at least one stiffening wire embedded in a wall of the distal shaft at the middle wall portion and configured to increase columnar strength of the distal shaft at the middle wall portion.

2. The catheter of claim 1 , wherein the stiffening wire extends past the middle wall portion into at least one of the proximal wall portion and the distal wall portion.

3. The catheter of claim 1 , wherein the stiffening wire terminates at a proximal end and a distal end of the middle wall portion.

4. The catheter of claim 1 , further comprising at least one pressure sensor wire extending through the proximal wall portion, the middle wall portion, and the distal wall portion, the at least one pressure sensor wire being coupled to the pressure sensor.

5. The catheter of claim 1 , wherein the skive is further configured to reduce a portion of an intra-stenosis lumen blocked by the catheter when the middle wall portion is deployed across a vascular stenosis.

6. The catheter of claim 1 , wherein the at least one stiffening wire is embedded in a same section of the middle wall portion as the skive is located.

7. The catheter of claim 1 , wherein the skive extends a varying depth into the distal shaft relative to the diameter of the distal shaft along the length.

8. The catheter of claim 1 , wherein the skive is configured to enable increased blood flow through the intra-stenosis lumen when the guidewire remains in place.

9. The catheter of claim 1 , wherein the skive is configured to enable blood flow through the guidewire lumen when the guidewire is retracted.

10. A method for calculating a fractional flow reserve in a vessel using a catheter, the method comprising:
delivering a distal shaft of the catheter to a treatment site in the vessel via a guidewire, the distal shaft defining a guidewire lumen configured to accommodate the guidewire and having a distal wall portion, a middle wall portion, and a proximal wall portion, the middle wall portion having a skive reducing a cross sectional profile of the distal shaft at the middle wall portion, extending radially through the middle wall portion to expose the guidewire lumen, configured to extend around a majority of a circumference of the distal shaft in at least a portion of the middle wall portion, and extending longitudinally along an entire length of the middle wall portion configured to extend across an intra-stenosis lumen of a stenosis of a patient vessel, and at least one stiffening wire embedded with a wall of the distal shaft at the middle wall portion, the at least one stiffening wire configured to increase columnar strength of the distal shaft at the middle wall portion, the catheter including a pressure sensor coupled to the distal wall portion, wherein the distal shaft is delivered to the treatment site such that the distal wall portion is disposed on a distal side of a stenosis of the vessel, the skive of the middle wall portion is disposed through an intra-stenosis lumen of the stenosis, and the proximal wall portion is disposed on a proximal side of the stenosis of the vessel,
measuring the distal pressure distal of the stenosis using the pressure sensor;
measuring a proximal pressure proximal of the stenosis; and
calculating the fractional flow reserve using the measured distal pressure and the measured proximal pressure.

11. The method of claim 10 , wherein the stiffening wire extends past the middle wall portion into at least one of the proximal wall portion and the distal wall portion.

12. The method of claim 10 , wherein the stiffening wire terminates at a proximal end and a distal end of the middle wall portion.

13. The method of claim 10 , wherein the catheter further comprises at least one pressure sensor wire extending through the proximal wall portion, the middle wall portion, and the distal wall portion, the at least one pressure sensor wire being coupled to the pressure sensor.

14. The method of claim 10 , wherein the middle wall portion having the skive disposed through the intra-stenosis lumen reduces a portion of the intra-stenosis lumen blocked by the catheter with respect to the distal wall portion being disposed through the intra-stenosis lumen.

15. The method of claim 10 , wherein the at least one stiffening wire is embedded in a same section of the middle wall portion as the skive is located.

16. The method of claim 10 , wherein the skive extends a varying depth into the distal shaft relative to the diameter of the distal shaft along the length.

17. The method of claim 10 , further comprising retracting the guidewire to permit blood flow through the exposed guidewire lumen prior to measuring a distal pressure.

18. The method of claim 10 , wherein measuring the distal pressure and measuring the proximal pressure are performed with the guidewire remaining in the guidewire lumen of the middle wall portion.

Assignees

• Medtronic Vascular Inc

Inventors

• Finn Ronan
• Kelly John
• Fleming Matthew

Classifications

• A61B5/6852

  Catheters · CPC title

• A61B5/026

  Measuring blood flow {(A61B3/1233, A61B3/1241 take precedence)} · CPC title

• A61B5/02007

  Evaluating blood vessel condition, e.g. elasticity, compliance · CPC title

• A61B2562/0247

  Pressure sensors · CPC title

• A61B5/0215 Primary

  by means inserted into the body · CPC title