Radially-expandable tubular elements for use in the construction of medical devices

• US 5,201,756 A
• Filed: 03/06/1992
• Issued: 04/13/1993
• Est. Priority Date: 06/20/1990
• Status: Expired due to Term

• Current Assignee: Credit Suisse First Boston (Credit Suisse)
• Original Assignee: Danforth Biomedical Incorporated
• Inventors: Sharkey, Hugh R., Horzewski, Michael J., Danforth, John W., Kraus, Jeff L.
• Primary Examiner(s): Thaler, Michael H.
• Application Number:
  US07/846,742
• Time in Patent Office: 403 Days
• Field of Search: 606/198, 604/104, 604/158, 604/264, 604/53, 604/164, 604/171, 128/4, 128/6
• US Class Current: 606/198
• CPC Class Codes: A61M 2025/0024 Expandable catheters or sheaths
• CPC Class Codes: A61M 25/0023 by the form of the lumen, e.g. cross-section, variable diameter
• CPC Class Codes: A61M 25/0662 Guide tubes

Abstract

A radially expandable intravascular medical device is disclosed. The device typically includes two members. The first member is an outer tube-shaped sheath which is radially expandable by being formed from elastic material or other means and having relatively low column strength. The second member is an inner portion extending throughout the outer tube. This inner portion includes a slit to allow it to expand radially as well. Using the structure diagnostic, therapeutic, or other desired objects may be conveyed through the device yet still enable the device to have a smaller cross-sectional area throughout most of its length than the object conveyed therethrough.

Claims

1. A composite tube for an intravascular medical device, the composite tube capable of conveying an object of a first cross-sectional profile therethrough, the composite tube comprising:

an outer tube having a first elasticity and radially expandable between a first position and a second position, the first position having a second cross-sectional profile smaller than the first cross-sectional profile, the second position having a third cross-sectional profile larger than the first cross-sectional profile; and

an inner member disposed inside the outer tube and extending longitudinally through the outer tube, the inner member having a second elasticity less than the first elasticity and defining a coaxially self-supporting channel, the inner member formed to include a sheet of material having a first edge and a second edge slidably overlapped in a rolled configuration forming a slit between the first edge and the second edge;

said outer tube being circumferentially continuous and fluid-impermeable and extending the full length of said inner tube.

2. A composite tube as in claim 1 wherein:

the outer tube is relatively flexible possessing a first column strength; and

the inner member is relatively inflexible possessing a second column strength the second column strength being greater than the first column strength.

3. A composite tube as in claim 1 wherein:

the inner member and the outer tube extend over a first length; and

the inner member is divided into at least two portions, a first portion having a first rigidity and a second portion having a second rigidity.

4. A composite tube of claim 1 having a proximal end and a distal end, the distal end being more flexible than the proximal end.

5. A composite tube for an intravascular medical device, the composite tube comprising:

an inner layer including a rolled sheet of material with a first elasticity, the rolled sheet having a first longitudinal edge and a second longitudinal edge overlapping to form a circumferentially coexisting junction wherein said first longitudinal edge and said second longitudinal edge are circumferentially slidable relative to each other to allow radial expansion and contraction of the rolled sheet of material; and

an outer tube of material having a second elasticity, the second elasticity greater than the first elasticity, the outer tube bonded to the inner layer between said first longitudinal edge and said second longitudinal edge wherein the cross-sectional profile of the outer tube is selected to elastically constrict the radial displacement of said first longitudinal edge and said second longitudinal edge;

said outer tube being circumferentially continuous and fluid-impermeable and extending the full length of said inner layer.

6. A composite tube as in claim 5 wherein the inner layer is constructed to provide coaxial support to the composite tube.

7. A composite tube of claim 5 further comprising a proximal end and a distal end wherein the distal end has a greater flexibility than the proximal end.

8. A composite tube as in claim 5 wherein the inner layer defines a radially expandable tube having a proximal end and a distal end, wherein said proximal end has a first rigidity and said distal end has a second rigidity and said first rigidity and said second rigidity are unequal.

9. The composite tube of claim 5 further comprising a fiber optic bundle disposed longitudinally in said inner layer.

10. A composite tube for an intravascular medical device, the composite tube comprising:

an outer tube having a first radial elasticity; and

an inner layer disposed within said outer tube, the inner layer formed from a sheet of relatively unpliant material wrapped into the configuration of a tube wherein an inside surface of said sheet and an outside surface of said sheet circunferentially overlap along a sliding junction, said inner layer longitudinally bonded to said outer tube and radially expandable therein;

said outer tube being circumferentially continuous and fluid-impermeable and extending the full length of said inner layer.

12. The composite tube of claim 10 further comprising a fiber optic bundle disposed longitudinally in said inner layer.

11. A composite tube for conveying a medical device therethrough, the composite tube comprising:

a first section having an outer tube of a first rigidity, a first resiliency and defining a shaft, an inner layer disposed within the outer tube, the inner layer formed of a sheet of material of a second rigidity and a second resiliency and rolled into a generally tubular configuration with an inside surface and an outside surface generally overlapping, wherein the outer tube has a first cross-sectional profile in the natural assembled condition and permits radial expansion upon conveyance of a device having a second, larger cross-sectional profile through said inner layer forcing said inner layer to expand radially and communicating radial forces upon said outer tube as said overlapping edges slide relative to each other;

said outer tube being circumferentially continuous and fluid-impermeable and extending the full length of said inner layer.