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EP-4736929-A2 - EXPANDABLE SHEATH WITH RADIOPAQUE FEATURES

EP4736929A2EP 4736929 A2EP4736929 A2EP 4736929A2EP-4736929-A2

Abstract

An introducer sheath can be used to safely introduce a delivery apparatus into a patient's vasculature (e.g., via the femoral artery). It is advantageous to visualize the placement of an introducer sheath within the vasculature using an imaging system. The sheaths disclosed herein include radiopaque features that assist with imaging without sacrificing the low profile, expandability, and other advantageous aspects of the introducer sheath.

Inventors

  • NEUMANN, YAIR A.
  • DAVIDESKO, AMIR
  • HICKS, Kristen
  • SHITRIT, Roy

Assignees

  • Edwards Lifesciences Corporation

Dates

Publication Date
20260506
Application Date
20211013

Claims (15)

  1. An expandable sheath for deploying a medical device, comprising: a first polymeric layer (707); a braided layer (704) positioned radially outward of the first polymeric layer (707), the braided layer (704) comprising a plurality of filaments (733) braided together; a radiopaque feature positioned radially outward of the first polymeric layer (707); and a second polymeric layer (709) positioned radially outward of the braided layer (704) and the radiopaque feature, the second polymeric layer (709) coupled to the first polymeric layer (707) such that the braided layer (704) and the radiopaque feature are encapsulated between the first and second polymeric layers (709); wherein when a medical device is passed through the sheath, the diameter of the sheath expands from a first diameter to a second diameter around the medical device.
  2. The expandable sheath of claim 1, wherein the radiopaque feature is a radiopaque polymer layer.
  3. The expandable sheath of claim 1, wherein the radiopaque feature is a longitudinally extending cord (717).
  4. The expandable sheath of claim 1, wherein the radiopaque feature is adjacent to and does not directly contact the braided layer (704).
  5. The expandable sheath of claim 4, wherein the radiopaque feature is positioned distal to a distal end (719) of the braided layer (704).
  6. The expandable sheath of claim 5, wherein the radiopaque feature comprises a circumferentially extending series of chevrons (723a-d).
  7. The expandable sheath of claim 6, wherein the chevrons of the circumferentially extending series of chevrons (723a-d) are connected to form a zig-zagged ring (721).
  8. The expandable sheath of claim 4, wherein the radiopaque feature is positioned within a cell of the braided layer (704).
  9. The expandable sheath of any one of claims 4-8, wherein the radiopaque feature is indirectly coupled to a filament (733) of the braided layer (704).
  10. The expandable sheath of any one of claims 1-3, wherein the radiopaque feature directly contacts a filament (733) of the braided layer (704).
  11. The expandable sheath of claim 10, wherein the filament (733) mates with a groove on the radiopaque feature.
  12. The expandable sheath of claim 10, wherein the radiopaque feature comprises a radiopaque coating on the filament (733).
  13. The expandable sheath of claim 10, wherein distal ends of two circumferentially adjacent filaments (733a, 733b) are joined by the radiopaque feature.
  14. The expandable sheath of claim 1, wherein a filament (733) of the braided layer (704) extends through a lumen of the radiopaque feature (735; 736; 737).
  15. The expandable sheath of claim 14, wherein the radiopaque feature is a coil (735) or a tube (736).

Description

RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application number 63/091,722, filed October 14, 2020, which is incorporated by reference in its entirety for all purposes. FIELD The present application relates to expandable introducer sheaths for prosthetic devices such as transcatheter heart valves, and methods of making the same. BACKGROUND Endovascular delivery catheter assemblies are used to implant prosthetic devices, such as a prosthetic valve, at locations inside the body that are not readily accessible by surgery or where access without invasive surgery is desirable. For example, aortic, mitral, tricuspid, and/or pulmonary prosthetic valves can be delivered to a treatment site using minimally invasive surgical techniques. An introducer sheath can be used to safely introduce a delivery apparatus into a patient's vasculature (e.g., the femoral artery). An introducer sheath generally has an elongated sleeve that is inserted into the vasculature and a housing that contains one or more sealing valves that allow a delivery apparatus to be placed in fluid communication with the vasculature with minimal blood loss. Such introducer sheaths may be radially expandable. However, such sheaths tend to have complex mechanisms, such as ratcheting mechanisms that maintain the sheath in an expanded configuration once a device with a larger diameter than the sheath's original diameter is introduced. Existing expandable sheaths can also be prone to axial elongation as a consequence of the application of longitudinal force attendant to passing a prosthetic device through the sheath. Such elongation can cause a corresponding reduction in the diameter of the sheath, increasing the force required to insert the prosthetic device through the narrowed sheath. Accordingly, there remains a need in the art for an improved introducer sheath for endovascular systems used for implanting valves and other prosthetic devices. SUMMARY Expandable sheaths with one or more radiopaque features are disclosed herein. The radiopaque features improve visualization of the sheath within the body during a medical procedure. In some aspects, the sheath wall includes a tubular foil layer that functions as the radiopaque feature. The sheath wall also includes a tubular first polymeric layer that defines an inner lumen. The tubular, radiopaque foil layer is positioned radially outward of the first polymeric layer and extends circumferentially around the first polymeric layer. In a collapsed state, the sheath wall has a plurality of longitudinally extending folds that create a plurality of circumferentially spaced ridges and a plurality of circumferentially spaced valleys. When a medical device passes through the inner lumen of the sheath, it applies an outward radial force on the sheath wall. This outward force causes the sheath wall to expand radially from the collapsed state to an expanded state by at least partially unfolding the plurality of longitudinally extending folds such that the ridges and valleys level out. Unfolding the plurality of longitudinally extending folds causes a decrease in the total thickness of the sheath wall. In some aspects, the decrease in the sheath wall thickness can be detected by an imaging modality as a decrease in radiopacity. In some aspects, the sheath wall includes a second polymeric layer positioned radially outward of the foil layer. The foil layer can be encapsulated or sandwiched between the first and second polymeric layers. Some expandable sheaths disclosedd herein can include a first polymeric layer, a braided layer positioned radially outward of the first polymeric layer (the braided layer comprising a plurality of filaments braided together), a radiopaque feature positioned radially outward of the first polymeric layer, and a second polymeric layer positioned radially outward of the braided layer and the radiopaque feature. The second polymeric layer is coupled to the first polymeric layer such that the braided layer and the radiopaque feature are encapsulated between the first and second polymeric layers. When a medical device is passed through the sheath, the diameter of the sheath expands from a first diameter to a second diameter around the medical device. Some embodiments can include one or more additional radiopaque features. The one or more additional radiopaque features may be of the same type as the first radiopaque feature, or of one or more different types of radiopaque features. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a delivery system for a cardiovascular prosthetic device, according to one aspect.FIG. 2 illustrates an expandable sheath that can be used in combination with the delivery system of FIG. 1, according to one aspect.FIG. 3 is a magnified view of a portion of the expandable sheath of FIG. 2.FIG. 4 is a side elevation cross-sectional view of a portion of the expandable sheath of FIG. 2.FIG. 5A is a magnified view of a portion of the expandab