Collapsible catheter and method for calculating fractional flow reserve

Patent metadata

Field	Value
Publication number	US-11219741-B2
Application number	US-201715672749-A
Country	US
Kind code	B2
Filing date	Aug 9, 2017
Priority date	Aug 9, 2017
Publication date	Jan 11, 2022
Grant date	Jan 11, 2022

Abstract

A catheter for measuring a fractional flow reserve includes a proximal shaft, a distal shaft coupled to the proximal shaft, a pressure sensor coupled to the distal shaft, and at least one pressure sensor wire operably connected to the pressure sensor. The proximal shaft includes a radially expanded configuration and a radially collapsed configuration, wherein the proximal shaft has a first outer diameter in the radially expanded configuration and a second outer diameter smaller than the first outer diameter in the radially collapsed configuration. The distal shaft defines a guidewire lumen configured to receive a guidewire therein.

First claim

What is claimed is:

1. A catheter for measuring a fractional flow reserve, the catheter comprising:
a proximal shaft, wherein at least a proximal portion of the proximal shaft adjacent a hub of the catheter coupled to a proximal end of the proximal shaft includes a radially expanded configuration and a radially collapsed configuration, wherein at least the proximal portion of the proximal shaft has a first outer diameter in the radially expanded configuration and a second outer diameter in the radially collapsed configuration, wherein the first outer diameter is larger than the second outer diameter;
a distal shaft coupled to the proximal shaft, the distal shaft defining a guidewire lumen configured to receive a guidewire therein, wherein at least a portion of the distal shaft is not collapsible; and
a pressure sensor coupled to the distal shaft.

2. The catheter of claim 1 , further comprising a stiffening shaft movable within an expansion lumen of the proximal shaft, wherein the proximal shaft is in the radially expanded configuration with the stiffening shaft disposed in the expansion lumen, and wherein the proximal shaft is in the radially collapsed configuration with the stiffening shaft removed from the expansion lumen.

3. The catheter of claim 2 , wherein the proximal shaft is formed of a shape memory material including a pre-set shape.

4. The catheter of claim 3 , wherein the pre-set shape of the proximal shaft is the radially collapsed configuration, and wherein the proximal shaft is expanded to the radially expanded configuration by the stiffening shaft.

5. The catheter of claim 4 , wherein the proximal shaft comprises an extruded elastic material such that in the radially collapsed configuration the extruded elastic material collapses the expansion lumen, and wherein the stiffening shaft extending through the expansion lumen expands the expansion lumen such that the proximal shaft is in the radially expanded configuration.

6. The catheter of claim 4 , wherein the proximal shaft comprises a circumferentially continuous material layer, an elastic frame, and a partially non-circumferentially continuous material layer connected to the elastic frame and surrounding the circumferentially continuous material layer, the partially non-circumferentially continuous material layer having a gap,
wherein in the radially collapsed configuration the gap has a first circumferential length, and wherein in the radially expanded configuration the gap has a second circumferential length larger than the first circumferential length.

7. The catheter of claim 6 , wherein the circumferentially continuous layer includes a fold in the collapsed configuration, and wherein the circumferentially continuous layer unfolds to expand to the radially expanded configuration.

8. The catheter of claim 1 , further comprising at least one pressure sensor wire operably connected to the pressure sensor, wherein the at least one pressure sensor wire extends proximally from the pressure sensor within a distal shaft wall and extends proximally into a proximal shaft wall of the proximal shaft.

9. A method for calculating a Fractional Flow Reserve in a vessel, the method comprising the steps of:
delivering a catheter to a treatment site in the vessel, the catheter including a pressure sensor coupled to a distal shaft, a proximal shaft including a proximal end coupled to a hub, and a stiffening shaft disposed within an expansion lumen of the proximal shaft disposed at least adjacent to a proximal portion of the proximal shaft adjacent the hub, wherein the catheter is delivered to the treatment site with the stiffening shaft disposed in the expansion lumen and such that the pressure sensor is located on a distal side of a stenosis of the vessel;
removing the stiffening shaft from the expansion lumen such that at least the proximal portion of the proximal shaft collapses from a radially expanded configuration to a radially collapsed configuration, wherein at least a portion of the distal shaft does not collapse;
measuring a distal pressure distal of the stenosis using the pressure sensor;
measuring a proximal pressure on a proximal side of the stenosis, wherein the proximal pressure is measured with the proximal shaft in the radially collapsed configuration;
calculating the Fractional Flow Reserve using the measured distal pressure and the measured proximal pressure.

Assignees

• Medtronic Vascular Inc

Inventors

• Fleming Matthew
• Jones Timothy
• Hillas Joshua

Classifications

• A61M2025/0024

  Expandable catheters or sheaths · CPC title

• A61B5/02158

  provided with two or more sensor elements · CPC title

• A61B5/02028

  Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction · CPC title

• A61M2205/0266

  Shape memory materials · CPC title

• A61B5/02007

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