Microcatheter with modified ptfe liner

Patent metadata

Field	Value
Publication number	US-2020353206-A1
Application number	US-202016941342-A
Country	US
Kind code	A1
Filing date	Jul 28, 2020
Priority date	Jul 16, 2013
Publication date	Nov 12, 2020
Grant date	—

Abstract

A microcatheter with an enhanced inner liner that has low of friction and improved toughness which facilitates delivery of expandable vascular reconstruction devices.

First claim

1 . A method of making a catheter, the method comprising:
longitudinally stretching a portion of a PTFE tube having an initial length to a longer length that is 25% to 100% of the initial length of the portion to create a PTFE liner, wherein the longitudinally-stretched PTFE liner has a tensile strength greater than 20 kilopound per square inch (kpsi), wherein the catheter is configured to deploy an expandable device, and wherein an internal surface of the longitudinally-stretched PTFE liner has a radial coefficient of friction of 0.07 to 0.25 with respect to the expandable device, the radial coefficient of friction being a ratio of a radial force exerted by the expandable device on the longitudinally-stretched PTFE liner to a force required to pull the expandable device through the longitudinally-stretched PTFE liner when the expandable device is positioned within the catheter; wrapping a coil over at least a segment of the PTFE liner; and disposing a sheath over the coil.

2 . The method of claim 1 , wherein longitudinally stretching the portion of the PTFE tube to create the PTFE liner comprises:
tensioning the PTFE tube to lengthen at least the portion of the PTFE tube by about 25% to 100% of the initial length of the portion.

3 . The method of claim 1 , wherein longitudinally stretching the portion of the PTFE tube to create the PTFE liner comprises:
tensioning the PTFE tube while heating the PTFE tube, to lengthen at least the portion of the PTFE tube by about 25% to 100% of the initial length of the portion.

4 . The method of claim 1 , wherein the PTFE tube is characterized by an initial internal diameter, and wherein longitudinally stretching the PTFE tube to create the PTFE liner comprises:
drawing down the initial internal diameter of the PTFE tube by about 20% to 25% of the initial internal diameter.

5 . The method of claim 1 , wherein longitudinally stretching the portion of the PTFE tube to create the PTFE liner comprises:
applying heat over different longitudinal regions of the PTFE tube at different speeds while tensioning the PTFE tube to create different degrees of stretching.

6 . The method of claim 1 , wherein longitudinally stretching the portion of the PTFE tube to create the PTFE liner comprises:
tensioning the PTFE tube by suspending the PTFE tube vertically; attaching weights to the PTFE tube; and heating the PTFE tube to lengthen at least the portion of the PTFE tube.

7 . The method of claim 1 , wherein wrapping the coil over at least the segment of the PTFE liner comprises wrapping the coil over a distal segment of the PTFE liner, the method further comprising:
wrapping the coil over a proximal segment of the PTFE liner.

8 . The method of claim 1 , where the longitudinally-stretched PTFE liner has a tensile strength of about 28 kpsi.

9 . The method of claim 1 , wherein the longitudinally-stretched PTFE liner spans an entire length of the catheter.

10 . The method of claim 1 , wherein the longitudinally-stretched PTFE liner spans only a portion of a length of the catheter.

11 . The method of claim 1 , further comprising positioning the expandable device within the longitudinally-stretched PTFE liner, wherein the expandable device exerts the radial force on the longitudinally-stretched PTFE liner.

12 . The method of claim 1 , wherein the catheter further comprises proximal cross wound coils disposed over the PTFE liner in a proximal region of the catheter, the method further comprising wrapping the cross wound coils over a proximal segment of the PTFE liner.

13 . The method of claim 1 , wherein the portion of the PTFE tube has an initial radial coefficient of friction, and wherein the portion of the longitudinally-stretched PTFE liner has a lower radial coefficient of friction that is decreased by at least about 20% of the initial radial coefficient of friction.

14 . The method of claim 1 , wherein the portion of the PTFE tube has an initial tensile strength, and wherein the portion of the longitudinally-stretched PTFE liner has a greater tensile strength that is increased by about 50% to about 100% of the initial tensile strength.

15 . A method of making a catheter, the method comprising:
longitudinally stretching a portion of a PTFE tube having an initial length to a longer length that is 25% to 100% of the initial length of the portion to create the PTFE liner, wherein the longitudinally-stretched PTFE liner has a tensile strength greater than 20 kilopound per square inch (kpsi), wherein the catheter is configured to deploy an expandable device, and wherein an internal surface of the longitudinally-stretched PTFE liner has a radial coefficient of friction with respect to the expandable device, the radial coefficient of friction being a ratio of a radial force exerted by the expandable device on the longitudinally-stretched PTFE liner to a force required to pull the expandable device through the longitudinally-stretched PTFE liner when the expandable device is positioned within the catheter, wherein the portion of the PTFE tube has an initial radial coefficient of friction, and wherein the portion of the longitudinally-stretched PTFE liner has a lower radial coefficient of friction that is decreased by at least about 20% of the initial radial coefficient of friction; wrapping a coil over at least a segment of the PTFE liner; and disposing a sheath over the coil.

16 . The method of claim 15 , wherein longitudinally stretching the portion of the PTFE tube to create the PTFE liner comprises:
tensioning the PTFE tube while heating the PTFE tube, to lengthen at least the portion of the PTFE tube by about 25% to 100% of the initial length of the portion.

17 . The method of claim 15 , wherein the PTFE tube is characterized by an initial internal diameter, and wherein longitudinally stretching the PTFE tube to create the PTFE liner comprises:
drawing down the initial internal diameter of the PTFE tube by about 20% to 25% of the initial internal diameter.

18 . A catheter including a 25% to 100% longitudinally-stretched PTFE liner, wherein the longitudinally-stretched PTFE liner has a tensile strength greater than 20 kilopound per square inch (kpsi), wherein the catheter is configured to deploy an expandable device, and wherein an internal surface of the longitudinally-stretched PTFE liner has a radial coefficient of friction with respect to the expandable device, the radial coefficient of friction being a ratio of a radial force exerted by the expandable device on the longitudinally-stretched PTFE liner to a force required to pull the expandable device through the longitudinally-stretched PTFE liner when the expandable device is positioned within the catheter, wherein the portion of the PTFE tube has an initial radial coefficient of friction, and wherein the portion of the longitudinally-stretched PTFE liner has a lower radial coefficient of friction that is decreased by at least about 20% of the initial radial coefficient of friction.

19 . The catheter of claim 18 , further comprising the expandable device positioned within the longitudinally-stretched PTFE liner, wherein the expandable device exerts the radial force on the longitudinally-stretched PTFE liner.

20 . The catheter of claim 18 , wherein the portion of the PTFE tube has an initial tensile strength, and wherein the portion of the longitudinally-stretched PTFE liner has a greater tensile strength that is increased by about 50% to about 100% of the initial tensile strength.

Assignees

• Covidien Lp

Inventors

• Dinh James Q
• Valko Jeffrey J
• Strauss Brian M
• Peralta Adriana X

Classifications

• A61M2025/0047

  the inner layer having a higher lubricity · CPC title

• A61F2/95

  Instruments specially adapted for placement or removal of stents or stent-grafts · CPC title

• A61M25/0045

  multi-layered, e.g. coated (coating materials A61L29/08) · CPC title

• A61M25/005

  with embedded materials for reinforcement, e.g. wires, coils, braids · CPC title

• A61B2017/1205

  Introduction devices · CPC title