Methods and apparatus for an adjustable stiffness catheter

Patent metadata

Field	Value
Publication number	US-RE49557-E
Application number	US-202016790551-A
Country	US
Kind code	E1
Filing date	Feb 13, 2020
Priority date	Jan 6, 2011
Publication date	Jun 20, 2023
Grant date	Jun 20, 2023

Abstract

Apparatus and methods for an endovascular catheter that can be inserted within tortuous body anatomies and then selectively stiffened and fixed in place. In a particular embodiment, this stiffness is reversible. The stiffness or a comparable mechanical characteristic of the catheter assembly may be adjusted to a relatively low value during insertion (so that it easily navigates a guide wire or the like), and then subsequently adjusted to a relatively high value in situ to keep the catheter assembly substantially fixed in place (i.e., during delivery of an interventional device).

First claim

What is claimed is:

1. A catheter apparatus comprising:
a tubular body having a distal end, a proximal end, and a lumen defined therein, the tubular body having a first state, wherein the tubular body has a first value of a stiffness metric, and a second state, wherein the tubular body has a second value of the stiffness metric that is greater than the first value, the tubular body including:
at least two fluid impermeable layers defining a pressure-responsive chamber, and
an interstitial structure provided within the pressure-responsive chamber and comprising a plurality of layers including a first cylindrical layer of wrapped tape and a second cylindrical layer of wrapped tape coaxial with the first cylindrical layer of wrapped tape, the first and second cylindrical layers extending along an entire length of the pressure-responsive chamber,
the pressure responsive chamber configured to increase radial compression of the plurality of layers in response to negative internal pressure in the pressure-responsive chamber and to decrease radial compression of the plurality of layers in response to non-negative internal pressure in the pressure-responsive chamber,
the decrease in radial compression corresponding to a decrease in friction between the plurality of layers along of the interstitial structure and a decrease in the stiffness metric and the increase in radial compression of the plurality of layers of the interstitial structure corresponding to an increase in friction between the plurality of layers of the interstitial structure and an increase in the stiffness metric; and

a controller operatively coupled to the tubular body and configured to cause a change in the internal pressure within the pressure-responsive chamber to actuate the tubular body between the first state and second state.

2. The catheter apparatus of claim 1 , wherein the plurality of layers of the interstitial structure are configured to be substantially slideable slidable with respect to each other during the first state, and be substantially non-slidable with respect to each other during the second state.

3. The catheter apparatus of claim 2 , wherein the plurality of layers of the interstitial structure each define a substantially cylindrical, helically-wrapped layer.

4. The catheter apparatus of claim 1 , wherein the first layer of wrapped tape is a helically-wrapped ePTFE tape layer and the second layer of wrapped tape is a helically-wrapped ePTFE layer.

5. A catheter apparatus comprising:
a tubular body having a distal end, a proximal end, and a lumen defined therein, the tubular body including at least two fluid impermeable layers defining a pressure-responsive chamber and an interstitial structure provided within the pressure-responsive chamber, the interstitial structure comprising a first layer of wrapped tape and a second layer of wrapped tape, the first and second layers of wrapped tape extending along an entire length of the pressure-response chamber; and
activation means for selectably causing the tubular body to enter a first state and a second state;
wherein, in the first state, the tubular body has a first value of a stiffness metric that is equal to or less than a predetermined navigatibility navigability threshold;
wherein, in the second state, the tubular body has a second value of the stiffness metric that is greater than the first value and that is greater than or equal to a predetermined rigidity threshold value; and
wherein the activation means includes a controller communicatively coupled to the tubular body and adapted to place the tubular body in the second state by subjecting at least a portion of the tubular body to an increase in radial compression by causing negative pressure within the pressure-responsive chamber thereby causing the collapse of the pressure-responsive chamber.

6. The catheter apparatus of claim 5 , wherein the interstitial structure is adapted to exhibit radial compression in response to a change in internal pressure within the pressure responsive chamber caused by the controller.

7. The catheter apparatus of claim 6 , wherein the interstitial structure includes a layered structure having a plurality of layers configured to be substantially slideable slidable with respect to each other during the first state, and be substantially nonslideable non-slidable with respect to each other during the second state.

8. The catheter apparatus of claim 5 , wherein the pressure-responsive chamber is placed under negative pressure in the second state.

9. The catheter apparatus of claim 5 , wherein the controller is configured to cause the change of state by pneumatic activation.

10. The catheter apparatus of claim 5 , wherein the controller is a syringe.

11. The catheter apparatus of claim 5 , further comprising multiple discrete pressure-responsive chambers distributed along a length of catheter, and further wherein the activation means is configured to independently pressurize each of the discrete pressure-responsive chambers.

12. The catheter apparatus of claim 5 , wherein the first layer of wrapped tape is a helically-wrapped ePTFE tape layer and the second layer of wrapped tape is a helically-wrapped ePTFE layer.

13. A catheter comprising:
a catheter body having an outer body layer and an inner body layer disposed within the outer body layer to define an air-impermeable chamber there between, at least one of the inner and outer body layers comprising a flexible polymeric material that is at least partially collapsible upon a reduction of an internal pressure of the air-impermeable chamber; and an interstitial component (IC) disposed within the air-impermeable chamber, the interstitial component having at least two opposing portions including a first cylindrical layer and a second cylindrical layer coaxial with the first cylindrical layer and extending along an entire length of the air-impermeable chamber, the at least two opposing portions disposed between the inner and outer body layers and positioned to define a first state where the opposing portions are disposed such that the opposing portions slide across each other with minimal friction and to define a second state where the opposing portions abut each other such that layer-to-layer friction limits the opposing portions to slide with respect to each other, the first state defining a slidable engagement having a first state stiffness metric, the second state defining a non-slidable engagement having a second state stiffness metric, wherein a reversible transition from the first state to the second state is defined by the reduction of the internal pressure driving a collapse of the air-impermeable chamber during which at least one of the inner and outer body layers move towards the other to impart a radial force on the interstitial component, and wherein the reversible transition is further defined by a passive reversal of the collapse of the air-impermeable chamber to at least partially restore the first state during which the inner and outer body layers at least partially move away from each other to reestablish the space between the at least two opposing portions.

14. The catheter of claim 13, wherein the first cylindrical layer of the interstitial component has a first surface disposed to face a second surface of the second cylindrical layer of the interstitial component.

15. The catheter of claim 13, wherein bending of the body causes the first and second cylindrical layers of the interstitial component to slide across one another in the first state.

16. The catheter of claim 13, wherein the first and second cylindrical layer

Assignees

• Gore & Ass

Inventors

• Cully Edward H
• Duncan Jeffrey B
• Trapp Benjamin M

Classifications

• A61M2025/0025

  having a collapsible lumen · CPC title

• A61M25/0054

  with regions for increasing flexibility · CPC title

• A61M2025/0064

  which become stiffer or softer when heated · CPC title

• A61M2205/0266

  Shape memory materials · CPC title

• A61M25/0053 Primary

  having a variable stiffness along the longitudinal axis, e.g. by varying the pitch of the coil or braid · CPC title