Expandable introducer sheath

• US 6,183,443 B1
• Filed: 10/26/1998
• Issued: 02/06/2001
• Est. Priority Date: 10/15/1992
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Thome, Scott P., Richardson, Andrew G., Tay, Sew-Wah, Keith, Peter T., Kratoska, William F.
• Primary Examiner(s): Kennedy, Sharon
• Assistant Examiner(s): Thompson, Michael M
• Application Number:
  US09/179,231
• Time in Patent Office: 834 Days
• Field of Search: 604/280, 604/264, 604/523, 604/524, 604/526, 604/527, 604/530, 604/531, 604/532, 604/164, 604/170
• US Class Current: 604/164.03
• CPC Class Codes: A61B 17/3439 with means for changing the inner diameter of the cannula, e.g. expandable A61B17/3423, A61B17/3431 take precedence; catheters A61M25/0662
• CPC Class Codes: A61B 2017/00867 shape memory effect
• CPC Class Codes: A61M 2025/0024 Expandable catheters or sheaths
• CPC Class Codes: A61M 25/0662 Guide tubes

Abstract

The present invention comprises a method and device for providing an expandable introducer sheath. The method of employing the inventive device comprises inserting an elongate flexible tubular sheath into a vessel (with a proximal end of the sheath extending proximally outward through the skin), to slidably receive intravascular devices. When a larger size introducer sheath is desired, the sheath is manipulated while still in the vessel to expand its inner diameter to a larger size. In one embodiment, the sheath is made of a shape-memory polymer and is manipulated by inserting a heated mandrel (with an outer diameter larger than the inner diameter of the sheath) within the sheath to cause the sheath to expand to an inner diameter at least approximately equal to an outer diameter of the mandrel. The shape-memory polymer material ensures that the sheath will retain its expanded inner diameter. Alternatively, the sheath is formed from a telescoping multi-tubular arrangement of progressively larger tubes. In any case, insertion of the inventive sheath into the skin requires only a single small puncture which is then only expanded as needed while the sheath remains in place.

Claims

1. A sheath system for introducing intravascular devices percutaneously, the sheath system comprising:

a first elongate flexible tubular sheath for placement within a vessel to slidably receive intravascular devices, the first sheath including a wall having a continuous outer surface, the outer surface defining an outer diameter;

a second elongate flexible tubular sheath for placement within a vessel to slidably receive intravascular devices comprising a polymer material, the second sheath being coaxially slidable over the first sheath and being capable of percutaneously entering the vessel by distal advancement of the second sheath over the first sheath, the second sheath comprising a wall having a continuous outer surface and defining a first inner diameter at least equal to the outer diameter of the first sheath, the second sheath wall being selectively permanently expandable while within the vessel to define a second, larger inner diameter and maintaining a substantially uniform tubular shape without an additional member extending through the second sheath, wherein the polymer material is a shape-memory polymer having a glass transition temperature greater than the normal temperature of the human body so that the second sheath is capable of being forcibly expanded to define the second larger diameter and maintain the second diameter after the polymer has cooled to a temperature less than the glass transition temperature; and

an elongate mandrel having an outer diameter greater than the inner diameter of the of the second sheath, and having a heated proximal end, such that as the heated proximal end of the mandrel is forcibly inserted into the second sheath, the shape memory polymer is heated beyond the glass transition temperature and expands to define the second, larger diameter.

2. The sheath system of claim 1, wherein the shape memory polymer material is a polyurethane material with a tightly controlled glass transition temperature of about 45 degrees Celsius.

3. The sheath system of claim 1 wherein the second sheath further comprises:

a tubular braided material matrix embedded in the shape memory polymer material.