Expandable sheath

Inventors: Pu Zhou (Dove Canyon, CA); Erik Bulman (Lake Forest, CA); Timothy A. Geiser (Laguna Niguel, CA); Michael G. Valdez (Riverside, CA); Yidong M. Zhu (Irvine, CA); Baigui Bian (Laguna Niguel, CA); Sonny Tran (Westminster, CA); Richard D. White (Costa Mesa, CA); Thanh Huy Le (Oceanside, CA); Tung T. Le (Costa Mesa, CA); Alpana Kiran Gowdar (Irvine, CA)

Assignee: Edwards Lifesciences Corporation

A61M25/0662 A61F2/2433 A61F2/958 A61F2/011 A61M25/0023 A61M2025/0024

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Quick Facts

Patent No.: US 12685842
App. No.: 16/936,763
Granted: Jul 21, 2026
Kind: B2

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Abstract

A delivery sheath includes an outer tubular layer and an initially folded inner tubular layer. When an implant passes therethrough, the outer tubular layer expands and the inner tubular layer unfolds into an expanded lumen diameter. The sheath may also include selectively placed longitudinal support rods that mediate friction between the inner and outer tubular layers to facilitate easy expansion, thereby reducing the push force needed to advance the implant through the sheath's lumen.

Claims (36)

1 . A sheath comprising:

a circumferentially continuous elastic outer tubular layer defining an initial elastic lumen extending axially therethrough, the initial elastic lumen having an initial diameter; and

an inner tubular layer extending through the initial elastic lumen of the elastic outer tubular layer and comprising at least three circumferentially spaced, longitudinally extending thick wall segments and at least three circumferentially spaced, longitudinally extending thin wall segments, each of the at least three circumferentially spaced, longitudinally extending thin wall segments extending between two adjacent thick wall segments of the at least three circumferentially spaced, longitudinally extending thick wall segments so as to define an expanded lumen extending axially through the inner tubular layer, the expanded lumen having an expanded diameter larger than the initial diameter of the initial elastic lumen;

wherein the at least three circumferentially spaced, longitudinally extending thick wall segments compose a larger circumferential portion of the inner tubular layer than the at least three circumferentially spaced, longitudinally extending thin wall segments;

wherein the inner tubular layer, in a compressed condition, forms at least three circumferentially spaced folds, each of the at least three circumferentially spaced folds including a three-layer thickness in a radial direction comprised of portions of two adjacent thick wall segments of the at least three circumferentially spaced, longitudinally extending thick wall segments and a thin wall segment of the at least three circumferentially spaced, longitudinally extending thin wall segments sandwiched therebetween, with the two adjacent thick wall segments overlapping circumferentially;

wherein the sheath further comprises an arc-shaped retainer extending along a longitudinal portion of the sheath, the arc-shaped retainer defining a crescent-shaped space corresponding with a circumferential arc-length of a folded over portion of the inner tubular layer and configured to receive the folded over portion;

wherein the inner tubular layer, in a locally expanded condition, has the at least three circumferentially spaced, longitudinally extending thick wall segments and the at least three circumferentially spaced, longitudinally extending thin wall segments unfolded and expanded apart; and

wherein the inner tubular layer is configured to be urged by the elastic outer tubular layer at least partially back to the compressed condition after passage of an implant through the expanded lumen.

2 . The sheath of claim 1 , wherein the at least three circumferentially spaced, longitudinally extending thick wall segments do not overlap circumferentially when in the locally expanded condition.

3 . The sheath of claim 1 , wherein each of the at least three circumferentially spaced folds forms a stiffening element when in the compressed condition.

4 . The sheath of claim 1 , wherein at least one of an outer surface of the inner tubular layer or an inner surface of the elastic outer tubular layer has a lubricious coating.

5 . The sheath of claim 4 , wherein the lubricious coating forms a layer between the inner tubular layer and the elastic outer tubular layer, which allows free relative sliding of the elastic outer tubular layer and the inner tubular layer.

6 . The sheath of claim 4 , wherein the lubricious coating is disposed between the at least three circumferentially spaced, longitudinally extending thin wall segments and the at least three circumferentially spaced, longitudinally extending thick wall segments when in the compressed condition.

7 . The sheath of claim 4 , wherein the lubricious coating layer is disposed along the outer surface of the inner tubular layer when the sheath is in the locally expanded condition.

8 . The sheath of claim 1 , wherein an inner diameter of the inner tubular layer forms a circular cross-section.

9 . The sheath of claim 1 , wherein an outer diameter of the inner tubular layer forms a circular cross section.

10 . The sheath of claim 1 , further comprising a radiopaque tubular layer extending around a longitudinal portion of the elastic outer tubular layer.

11 . The sheath of claim 1 , wherein a distal portion of the elastic outer tubular layer is adhered to an expanded outer surface of the inner tubular layer.

12 . The sheath of claim 1 , wherein a distal portion of the elastic outer tubular layer and a distal portion of the inner tubular layer are adhered or sealed to each other.

13 . The sheath of claim 1 , wherein the longitudinal portion of the sheath including the arc-shaped retainer limits blood flow between various layers of the sheath.

14 . The sheath of claim 1 , wherein a distal portion of the sheath has a flared shape folded into an overlapping arrangement.

15 . The sheath of claim 1 , wherein the inner tubular layer is made of high-density polyethylene.

16 . The sheath of claim 1 , wherein the at least three circumferentially spaced, longitudinally extending thick wall segments includes a first, second, and third wall segment, each equally spaced apart about a circumference of the inner tubular layer, and

wherein the at least three thin wall segments includes a first, second, and third thin wall segment, each equally spaced about the circumference of the inner tubular layer.

17 . The sheath of claim 1 , wherein the at least three circumferentially spaced, longitudinally extending thick wall segments end at substantially a same longitudinal position.

18 . A method of inserting an implant into a blood vessel of a patient, the method comprising:

inserting a sheath at least partially into the blood vessel;

advancing the implant through the sheath, thereby exerting an outwardly directed radial force onto an inner tubular layer of the sheath which is initially compressed;

unfolding at least three circumferentially spaced folds of the inner tubular layer, thereby removing a circumferential overlap between two adjacent thick wall segments and also removing a folded over portion of the inner tubular layer from an arc-shaped retainer extending along a longitudinal portion of the sheath;

expanding apart at least three thick wall segments and at least three thin wall segments of the inner tubular layer to locally expand the inner tubular layer, the at least three thick wall segments composing a larger circumferential portion of the inner tubular layer than the at least three thin wall segments;

removing the implant from the sheath; and

locally contracting the inner tubular layer from the locally expanded condition at least partially back to a compressed condition using an inwardly directed radial force of an elastic outer tubular layer.

19 . The method of claim 18 , wherein the inner tubular layer is coaxially disposed inside an elastic lumen defined by the elastic outer tubular layer, the method further comprising advancing the inner tubular layer in an axial direction, with respect to the elastic outer tubular layer.

20 . The method of claim 18 , wherein the expanding apart the at least three thick wall segments and the at least three thin wall segments further comprises sliding two overlapping adjacent thick wall segments circumferentially away from each other.

21 . The method of claim 18 , wherein the expanding apart the at least three thick wall segments and the at least three thin wall segments further comprises fully exposing the at least three thin wall segments to an inner lumen of the inner tubular layer.

22 . The method of claim 18 , further comprising limiting blood flow between various layers of the sheath.