FRAMED BIODEGRADABLE YARN STRUCTURE AND METHOD

Abstract

The techniques of this disclosure generally relate to a prosthesis including framed biodegradable yarn graft material having a frame and biodegradable yarns combined with the frame. The biodegradable yarns seal tissue integration openings within the frame. The frame provides long term mechanical strength while the biodegradable yarns provide acute strength and impermeability to prevent endoleaks. As the biodegradable yarns degrade, the drop in textile density creates tissue integration openings, through which tissue grows. The integrate of tissue into the framed biodegradable yarn graft material provides biological fixation of the prosthesis in vessels and prevents endoleaks and migration of the prosthesis.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 62/591,601, filed on Nov. 28, 2017, entitled “ADVANCED GRAFT MATERIALS FOR ENDOVASCULAR APPLICATIONS” of Borglin et al., which is incorporated herein by reference in its entirety.

FIELD

The present technology is generally related to an intra-vascular device and method. More particularly, the present application relates to a device for treatment of intra-vascular diseases.

BACKGROUND

A conventional stent-graft typically includes a radially expandable reinforcement structure, formed from a plurality of annular stent rings, and a cylindrically shaped layer of graft material defining a lumen to which the stent rings are coupled. Stent-grafts are well known for use in tubular shaped human vessels.

To illustrate, endovascular aneurysmal exclusion is a method of using a stent-graft to exclude pressurized fluid flow from the interior of an aneurysm, thereby reducing the risk of rupture of the aneurysm and the associated invasive surgical intervention. The graft material of traditional stent-grafts is extremely hydrophobic and presents a hostile environment for the recruitment and proliferation of cells. The inability of tissue to integrate into the graft material prevents the biological fixation of the stent-graft in vessels and makes the stent-graft susceptible to endoleaks and migration.

SUMMARY

The techniques of this disclosure generally relate to a prosthesis including framed biodegradable yarn graft material having a frame and biodegradable yarns combined with the frame. The biodegradable yarns seal tissue integration openings within the frame. The frame provides long term mechanical strength while the biodegradable yarns provide acute strength and impermeability to prevent endoleaks. As the biodegradable yarns degrade, the drop in textile density creates tissue integration openings, through which tissue grows. The integrate of tissue into the framed biodegradable yarn graft material provides biological fixation of the prosthesis in vessels and prevents endoleaks and migration of the prosthesis.

In one aspect, the present disclosure provides a frame and biodegradable yarns combined with the frame.

In another aspect, the disclosure provides a prosthesis including a proximal seal zone including a framed biodegradable yarn graft material and an exclusion zone including permanent and impermeable graft material.

In yet another aspect, the disclosure provides a method including forming a prosthesis by forming a framed biodegradable yarn graft material by combining biodegradable yarns with a frame.

The details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a framed biodegradable yarn stent-graft in accordance with one embodiment.

FIG. 2 is an enlarged perspective view of a region II of the stent-graft of FIG. 1 in accordance with one embodiment.

FIG. 3 is a plan view of the region II of the stent-graft of FIG. 1 in accordance with one embodiment.

FIG. 4 is a cross-sectional view of a graft material along the line IV-IV of FIG. 3 upon initial deployment on a vessel wall in accordance with one embodiment.

FIG. 5 is an enlarged plan view of the section of the graft material of FIG. 3 after dissolution of biodegradable yarns in accordance with one embodiment.

FIG. 6 is a cross-sectional view of the graft material along the line VI-VI of FIG. 5 after a period of time after deployment on the vessel wall in accordance with one embodiment.

FIG. 7 is a cross-sectional view of a vessel assembly including the stent-graft of FIG. 1 after initial deployment within a vessel having a dissection in accordance with one embodiment.

FIG. 8 is an enlarged cross-sectional view of a region VIII of the vessel assembly of FIG. 7 in accordance with one embodiment.

FIG. 9 is a cross-sectional view of the region VIII of the vessel assembly of FIG. 7 after a period of time after deployment of the stent-graft within the vessel in accordance with one embodiment.

FIG. 10 is a cross-sectional view of a vessel assembly including a stent-graft in accordance with another embodiment.

DETAILED DESCRIPTION

FIG. 1 is a perspective view of a framed biodegradable yarn stent-graft 100 in accordance with one embodiment. Referring now to FIG. 1, stent-graft 100, sometimes called a prosthesis, includes a framed biodegradable yarn graft material 102 and one or more stent rings 104 coupled to graft material 102. Illustratively, stent rings 104 are self-expanding stent rings, e.g., nickel titanium alloy (NiTi), sometimes called Nitinol, or self-expanding members. The inclusion of stent rings 104 is optional and in one embodiment stent rings 104 are not included. In another embodiment, stent rings 104 are balloon expandable stents.

In accordance with this embodiment, graft material 102 includes a proximal opening 106 at a proximal end 108 of graft material 102 and a distal opening 110 at a distal end 112 of graft material 102.

Further, stent-graft 100 includes a longitudinal axis L. A lumen 114 is defined by graft material 102, and generally by stent-graft 100. Lumen 114 extends generally parallel to longitudinal axis L and between proximal opening 106 and distal opening 110 of stent-graft 100.

As used herein, the proximal end of a prosthesis such as stent-graft 100 is the end closest to the heart via the path of blood flow whereas the distal end is the end furthest away from the heart during deployment. In contrast and of note, the distal end of the catheter is usually identified to the end that is farthest from the operator/handle while the proximal end of the catheter is the end nearest the operator/handle.

For purposes of clarity of discussion, as used herein, the distal end of the catheter is the end that is farthest from the operator (the end furthest from the handle) while the distal end of stent-graft 100 is the end nearest the operator (the end nearest the handle), i.e., the distal end of the catheter and the proximal end of stent-graft 100 are the ends furthest from the handle while the proximal end of the catheter and the distal end of stent-graft 100 are the ends nearest the handle. However, those of skill in the art will understand that depending upon the access location, stent-graft 100 and the delivery system descriptions may be consistent or opposite in actual usage.

Graft material 102 is cylindrical having a substantially uniform diameter. However, in other embodiments, graft material 102 varies in diameter, is bifurcated at distal end 112, and/or is a multi-limbed device for branching applications. Graft material 102 includes an inner surface 116 and an opposite outer surface 118, e.g., cylindrical surfaces in accordance with this embodiment.

FIG. 2 is an enlarged perspective view of the region II of stent-graft 100 of FIG. 1 in accordance with one embodiment. FIG. 3 is a plan view of the region II of stent-graft 100 of FIG. 1 in accordance with one embodiment. Referring now to FIGS. 1, 2, and 3 together, graft material 102 includes a frame 220 and biodegradable yarns 222.

In one embodiment, frame 220 is permanent, e.g., will last in the human body for an extended period of time such as 10 years or more. Frame 220 is sometimes called non-absorbable, and persistent. In one embodiment, frame 220 is polyester terephthalate (PET), expanded polyester terephthalate (ePET), nickel titanium alloy (NiTi), or other permanent graft material or textile.

In contrast to frame 220, biodegradable yarns 222 are a biodegradable material, i.e., are biodegradable. As used herein, biodegradable means capable of being broken down in the human body, e.g., through contact with fluid such as blood and/or tissue such as a vessel wall. Examples of biodegradable yarns 222 include polymer polyglycolic-lactic acid (PLGA), poly(glycerol sebacate) (PGS), Polyglycolic acid (PGA), or Poly Lactic Acid (PLA).

Frame 220 provides long term mechanical strength while biodegradable yarns 222 provide acute strength and impermeability to prevent endoleaks. As discussed in further detail below, as biodegradable yarns 222 degrade, the drop in textile density creates tissue integration openings, sometimes called ingress channels, through which tissue grows.

In accordance with this embodiment, frame 220 includes permanent yarns 224. Biodegradable yarns 222 are combined with permanent yarns 224 and more generally with frame 220 to form graft material 102. Generally, graft material 102 includes permanent yarns 224 and biodegradable yarns 222 which are woven, knitted, sewn, or otherwise combined to create graft material 102. In one embodiment, yarns are long string like members, sometimes called threads, fibers, filaments, or cylindrical structures.

Biodegradable yarns 222 are illustrated as including a plurality of vertical biodegradable yarns 222V and a plurality of horizontal biodegradable yarns 222H. Similarly, permanent yarns 224 illustrated as including a plurality of vertical permanent yarns 224V and a plurality of horizontal permanent yarns 224H. Yarns 222V, 222H, 224V, 224H are interlaced with one another.

In accordance with this embodiment, each yarn 222, 224 is interlaced with the other yarns 222, 224 in a weaving pattern, e.g., an over under pattern. For example, two adjacent horizontal permanent yarns 224H are interlaced, e.g., in an over under or weaving pattern, with two adjacent vertical horizontal permanent yarns 224V in the view of FIGS. 2 and 3. This pattern is repeated to form frame 220.

Similarly, each biodegradable yarn 222 interlaced with frame 220 and the other biodegradable yarns 222 in a weaving pattern. In accordance with this embodiment, there is a ratio of three biodegradable yarns 222 to each permanent yarn 224, e.g., a 3/1 ratio. More generally, there are more biodegradable yarns 222 than permanent yarns 224. In addition, a diameter D1 of biodegradable yarns 222 is less than a diameter D2 of permanent yarns 224.

However, depending upon the application, the size of yarns 222, 224 and the weave pattern can be different than that illustrated in FIGS. 2-3. For example, the ratio of biodegradable yarns 222 to permanent yarns 224 is more or less than 3/1 in other embodiments. Further, diameter D1 of biodegradable yarns 222 is equal to or greater than diameter D2 of permanent yarns 224 in other embodiments.

The illustrated arrangement of yarns 222, 224, e.g., woven, is illustrative only and in light of this disclosure those of skill in the art will understand that yarns 222, 224 can be combined in any one of a number of different fashions to form graft material 102. For example, yarns 222, 224 are woven, knitted, sewn, or otherwise combined to create graft material 102.

A tissue integration opening 226, e.g., a space, is defined by the two adjacent horizontal permanent yarns 224H and the two adjacent vertical permanent yarns 224V illustrated in FIGS. 2 and 3. More particularly, tissue integration opening 226 is defined by two adjacent vertical permanent yarns 224V and two adjacent horizontal permanent yarns 224H. The other tissue integration openings 226 in graft material 102 are defined in a similar manner.

Tissue integration openings 226 are sealed by biodegradable yarns 222. In accordance with the embodiment illustrated in FIGS. 2 and 3, tissue integration openings 226 are sealed by three horizontal biodegradable yarns 222H interlaced with three vertical biodegradable yarns 222V. Generally, tissue integration openings 226 in frame 220 are sealed by biodegradable yarns 222.

As tissue integration openings 226 are sealed by biodegradable yarns 222, graft material 102 is essentially impermeable. In one embodiment, there are small pores 228, sometimes called interstices 228, between yarns 222, 224. Pores 228 are typically formed due to the overlapping nature of yarns 222, 224 and the inability to make yarns 222, 224 completely flush with one another along the entire length of yarns 222, 224. However, pores 228 are sufficiently small that fluid leakage through pores 228 is negligible. Although pores 228 are illustrated, in other embodiments, graft material 102 has an absence of pores and is completely impermeable.

Over time, biodegradable yarns 222 biodegrade and dissolve. This removes biodegradable yarns 222 from tissue integration openings 226 of frame 220, sometimes called opens tissue integration openings 226. Once opened, tissue integration openings 226 provide ingress channels in graft material 102 to encourage tissue integration therein. An example of the dissolution of biodegradable yarns 222 and tissue integration into tissue integration openings 226 is set forth below in reference to FIGS. 3-6.

FIG. 4 is a cross-sectional view of graft material 102 along the line IV-IV of FIG. 3 upon initial deployment on a vessel wall 402 in accordance with one embodiment.

Referring now of FIGS. 1, 3 and 4 together, stent-graft 100 is deployed within a vessel including the vessel wall 402. For example, stent-graft 100 is deployed to treat an abdominal aortic aneurysm, a thoracic aortic aneurysm, a dissection, or other medical condition.

Upon initial deployment, biodegradable yarns 222 remain in their original form and are undissolved. As discussed above, prior to dissolution of biodegradable yarns 222, graft material 102 is essentially impermeable. This, in turn, minimizes and essentially eliminates leaks through graft material 102, e.g., type IV endoleaks.

Paying particular attention to FIGS. 1 and 4 together, stent-graft 100 contacts vessel wall 402. Accordingly, fluid flows though stent-graft 100, i.e., through lumen 114. Due to the impermeability of stent-graft 100, vessel wall 402 including any defect associated therewith, e.g., a dissection or aneurysm, are excluding from the pressurized fluid flow through stent-graft 100.

FIG. 5 is an enlarged plan view of the section of graft material 102 of FIG. 3 after dissolution of biodegradable yarns 222 in accordance with one embodiment. FIG. 6 is a cross-sectional view of graft material 102 along the line VI-VI of FIG. 5 after a period of time after deployment on vessel wall 402 in accordance with one embodiment.

Referring now of FIGS. 1, 5-6 together, after a period of time, biodegradable yarns 222 (see FIGS. 3-4) dissolve. However, frame 220 including permanent yarns 224 remain in the same configuration as when initially deployed or approximately there so.

Biodegradable yarns 222 slowly dissolve over a period of time. As biodegradable yarns 222 dissolve, tissue integration openings 226 are uncovered by biodegradable yarns 222 and opened.

Over time, biodegradable yarns 222 are replaced with tissue 604 from vessel wall 402 that integrates within and through tissue integration openings 226 as illustrated in FIG. 6. Tissue 604 encases frame 220 including permanent yarns 224 and fills tissue integration openings 226 preventing leakage through tissue integration openings 226 in accordance with this embodiment. The integrate of tissue 604 into graft material 102 provides biological fixation of stent-graft 100 in vessels and prevents endoleaks and migration of stent-graft 100. Generally, stent-graft 100 becomes integrated with the vessel including vessel wall 402.

As discussed below in reference to FIGS. 7-10, stent-graft 100 is used to cover and treat various defects in a vessel.

FIG. 7 is a cross-sectional view of a vessel assembly 700 including stent-graft 100 of FIG. 1 after initial deployment within a vessel 702 having a dissection in accordance with one embodiment. FIG. 8 is an enlarged cross-sectional view of a region VIII of vessel assembly 700 of FIG. 7 in accordance with one embodiment. In FIG. 7, stent-ring 104 is not illustrated for simplicity.

Referring to FIGS. 1, 7-8 together, a dissection is a condition in which an inner layer 706 of vessel 702 tears to have a dissection opening 708. Fluid, e.g., blood, flows through dissection opening 708 and into a false lumen 710 between inner layer 706 and one or more other outer layers 712 of vessel 702. Left untreated, false lumen 710 can rupture outer layers 712 of vessel 702 leading to serious complications and often death.

In accordance with this embodiment, stent-graft 100 is deployed to cover and exclude dissection opening 708. As discussed above, when initially deployed, stent-graft 100 is impermeable thus sealing dissection opening 708 and preventing pressurized fluid flow through false lumen 710.

FIG. 9 is a cross-sectional view of region VIII of vessel assembly 700 of FIG. 7 after a period of time after deployment of stent-graft 100 within vessel 702 in accordance with one embodiment. Referring now to FIGS. 1, 7-9, due to the covering and exclusion of the dissection with stent-graft 100, dissection opening 708 heals and closes and false lumen 710 collapses. At the same time, biodegradable yarns 222 dissolve allowing tissue 904 integration into tissue integration openings 226 of stent-graft 100 including between permanent yarns 224 of frame 220.

FIG. 10 is a cross-sectional view of a vessel assembly 1002 including a stent-graft 1000 in accordance with another embodiment. Stent-graft 1000 of FIG. 10 is similar to stent-graft 100 of FIG. 1 and only the significant differences are discussed below. Stent-graft 1000 is illustrated with an absence of stent-rings 104 for simplicity but includes stent-rings 104 in other embodiments.

In accordance with this embodiment, a graft material 1001 and more generally stent-graft 1000 includes at least three zones 1004, 1006, 1008 in accordance with this embodiment. Proximal seal zone 1004 extends from proximal end 108 to exclusion zone 1006. Exclusion zone 1006 extends from proximal seal zone 1004 to distal seal zone 1008. Distal seal zone 1008 extends from exclusion zone 1006 to distal end 112.

Proximal seal zone 1004 and distal seal zone 1008 include framed biodegradable yarn graft material 102 similar to that discussed. More particularly, only proximal seal zone 1004 and distal seal zone 1008 include framed biodegradable yarn graft material 102 having frame 220 and biodegradable yarns 222.

However, exclusion zone 1006 is formed of non-biodegradable material, is permanent, and impermeable. For example, in accordance with various embodiments, exclusion zone 1006 is graft material made of polyester terephthalate (PET), ePET, or other similar graft material or textile.

Stent-graft 1000 is deployed into a vessel 1010 to exclude an aneurysm 1012 using any one of a number of techniques well known to those of skill in the art. More particularly, proximal seal zone 1004 and distal seal zone 1008 are deployed proximally and distally to aneurysm 1012, respectively.

Proximal seal zone 1004 and distal seal zone 1008 directly contact a vessel wall 1014 of vessel 1010. Over time, biodegradable yarns 222 of proximal seal zone 1004 and distal seal zone 1008 dissolve. This allows tissue integration into proximal seal zone 1004 and distal seal zone 1008 of stent-graft 1000 in a manner similar to that discussed above. This, in turn, prevents leakage around proximal seal zone 1004 and distal seal zone 1008 and migration of stent-graft 1000.

Further, exclusion zone 1006 is deployed over aneurysm 1012, i.e., to exclude aneurysm 1012. Accordingly, blood flows through exclusion zone 1006 and more generally through stent-graft 1000 thus excluding aneurysm 1012. As exclusion zone 1006 may not contact vessel wall 1014 but span aneurysm 1012, exclusion zone 1006 does not include biodegradable material such that tissue integration openings 226, e.g., see tissue integration openings 226 of FIGS. 5-6, are not created in stent-graft 1000 in exclusion zone 1006.

It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques). In addition, while certain aspects of this disclosure are described as being performed by a single module or unit for purposes of clarity, it should be understood that the techniques of this disclosure may be performed by a combination of units or modules associated with, for example, a medical device.

In one or more examples, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include non-transitory computer-readable media, which corresponds to a tangible medium such as data storage media (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer).

Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor” as used herein may refer to any of the foregoing structure or any other physical structure suitable for implementation of the described techniques. Also, the techniques could be fully implemented in one or more circuits or logic elements.

Claims

1. A prosthesis comprising:

a frame; and

biodegradable yarns combined with the frame.

2. The prosthesis of claim 1 where the frame comprises permanent yarns.

3. The prosthesis of claim 2 wherein a diameter of the permanent yarns is greater than a diameter of the biodegradable yarns.

4. The prosthesis of claim 2 wherein there are more biodegradable yarns than permanent yarns.

5. The prosthesis of claim 1 wherein the frame comprises tissue integration openings.

6. The prosthesis of claim 5 wherein the tissue integration openings are sealed by the biodegradable yarns.

7. The prosthesis of claim 5 wherein each of the tissue integration openings are defined by two adjacent vertical permanent yarns of the frame and two adjacent horizontal permanent yarns of the frame.

8. The prosthesis of claim 1 wherein the frame and the biodegradable yarns are woven together.

9. The prosthesis of claim 1 further comprising a framed biodegradable yarn graft material comprising the frame and the biodegradable yarns.

10. The prosthesis of claim 9 further comprising at least one stent ring coupled to the framed biodegradable yarn graft material.

11. A prosthesis comprising:

a proximal seal zone comprising a framed biodegradable yarn graft material; and

an exclusion zone comprising permanent and impermeable graft material.

12. The prosthesis of claim 11 further comprising:

a distal seal zone comprising the framed biodegradable yarn graft material.

13. The prosthesis of claim 12 wherein the exclusion zone extends from the proximal seal zone to the distal seal zone.

14. The prosthesis of claim 11 wherein the framed biodegradable yarn graft material comprises permanent yarns combined with biodegradable yarns.

15. The prosthesis of claim 14 wherein the permanent yarns are woven with the biodegradable yarns.

16. A method comprising:

forming a prosthesis comprising:

forming a framed biodegradable yarn graft material by combining biodegradable yarns with a frame.

17. The method of claim 16 further comprising sealing tissue integration openings within the frame with the biodegradable yarns.

18. The method of claim 17 further comprising deploying the prosthesis within a vessel, wherein the framed biodegradable yarn graft material contacts a vessel wall of the vessel.

19. The method of claim 18 wherein the biodegradable yarns biodegrade opening the tissue integration openings.

20. The method of claim 19 wherein tissue from the vessel wall fills the tissue integration openings and encases the frame.