BIFURCATED SIDE-ACCESS INTRAVASCULAR STENT GRAFT
A bifurcated intravascular stent graft comprises primary stent segments and a primary graft sleeve, forming a main fluid channel and having a side opening therethrough. An external graft channel formed on the primary graft sleeve has a first end communicating with the side opening and an open second end outside the primary graft sleeve, thereby providing a branch flow channel from the main channel out through the side opening and external graft channel. The primary stent segments and graft sleeve engage an endoluminal surface of a main vessel and form substantially fluid-tight seals. The stent graft further comprises a secondary stent graft, which may be positioned partially within the external graft channel, through the open second end thereof, and partially within a branch vessel. The secondary stent graft engages the inner surface of the external graft channel and the endoluminal surface of the branch vessel, thereby forming substantially fluid-tight seals.
This application is a Continuation of U.S. application Ser. No. 13/906,247, filed May 30, 2013, which is a division of U.S. application Ser. No. 10/277,641, filed Oct. 22, 2002, the contents of which are hereby incorporated by reference in their entireties.
BACKGROUND FieldThe field of the present invention relates to intravascular stent grafts. In particular, a bifurcated side-access intravascular stent graft and methods for fabricating and deploying the same are described herein.
DiscussionIn many instances of vascular disease, a damaged, weakened, and/or enlarged portion of a blood vessel must be protected from intravascular fluid pressure. Continued exposure to such fluid pressure may result in progression of damage to the affected area and/or vessel failure, accompanied by significant morbidity or even sudden death. A well-established technique for treating such vascular damage is the use of transluminally-deployed stent grafts.
Briefly, a stent graft comprises two major components, a stent and a graft. The stent (one or more) typically takes the form of a somewhat stiff tube-like structure inserted into an affected vessel and fixed in place. The stent may serve to maintain a patent vessel lumen, may serve as structural support for the vessel, and/or may serve as an attachment/seal for a graft. A graft typically takes the form of a flexible tube or sleeve which is at least somewhat fluid-tight (although varying degrees of permeability may be desirable for a variety of reasons). When secured within a vessel using stents (a single stent the length of the graft, a pair of stent segments at the ends of the graft, or multiple stent segments spaced along the length of the graft), the graft becomes a surrogate vessel-within-a-vessel, and bears the brunt of the intravascular fluid pressure. It has become common practice to bridge damaged vessel segment using a sufficiently long graft secured within the vessel with stent segments.
Complications arise, however, when vessel damage occurs near a vessel branch point. More elaborate, multi-component devices are required to both shield the damaged vessel portion while maintaining blood flow through the main and branch vessels. Such devices are described in the following patents and references cited therein. Each of the following patents is hereby incorporated by reference as if fully set forth herein: U.S. Pat. Nos. 5,906,641; 6,093,203; 5,855,598; 5,972,023; 6,129,756; 5,824,040; 5,628,787; and 5,957,974.
Many of the prior-art devices are suitable for vessel branches where the branch vessel leaves the main vessel at a relatively small angle (less than about 45°, or example). For larger branching angles (as large as about 90° or even up to about 180°, for example) many prior art devices are not suitable. Such large branching angles occur at several potentially important repair sites (particularly along the abdominal aorta, at the renal arteries, celiac artery, superior and inferior mesenteric arteries, for example). Another drawback common to many devices of the prior-art is the need for transluminal access through the branch vessel from a point distal of the repair site. In many instances such access is either impossible (celiac artery, mesenteric arteries, renal arteries) or extremely difficult and/or dangerous (carotid arteries). Still other previous devices do not provide a substantially fluid-tight seal with the branch vessel, thereby partially defeating the purpose of the stent graft (i.e., shielding the repaired portion of the main vessel and/or branch vessel from intravascular fluid pressure).
It is therefore desirable to provide a bifurcated side-access intravascular stent graft and methods for fabricating and deploying the same, wherein the stent graft may be deployed transluminally to repair vessels having large-angle branch vessels (ranging from about 0° up to about 180°, for example). It is therefore desirable to provide a bifurcated side-access intravascular stent graft and methods for fabricating and deploying the same, providing a substantially fluid-tight seal with the main vessel and the branch vessel. It is therefore desirable to provide a bifurcated side-access intravascular stent graft and methods for fabricating and deploying the same, wherein the stent graft may be deployed transluminally without distal access through the branch vessel. It is therefore desirable to provide a bifurcated side-access intravascular stent graft and methods for fabricating and deploying the same, wherein the stent graft may be readily and accurately positioned relative to the branch vessel.
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention.
The embodiments shown in the Figures are exemplary, and should not be construed as limiting the scope of the present invention as disclosed and/or claimed herein.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTSFor purposes of the present written description and/or claims, “proximal” shall denote the direction along a vessel system in which multiple smaller vessels come together to form a larger vessel, and “distal” shall denote the opposite direction, i.e., the direction in which a larger vessel divides into multiple smaller vessels. For an arterial system proximal therefore corresponds to “upstream”, while distal corresponds to “downstream”. It should be noted that fora venous system or a lymphatic system, the correspondence would be reversed. The correspondence may vary for other vascular or duct systems.
A bifurcated intravascular primary stent graft 100 according to the present invention is illustrated in
A bifurcated intravascular stent graft according to the present invention may comprise a primary stent graft 100 and may further comprise a secondary stent graft 300 as illustrated in
The stent graft of the present invention is particularly well-suited for repair of main vessel segments where a branch vessel leaves the main vessel at an angle approaching 90°. Previous bifurcated stent graft devices enable repairs where a branch vessel leaves the main vessel at a substantially smaller angle of less than about 45°. This condition does not obtain at several potentially important vessel repair sites. Other previous devices enable repair at such high-angled branches only when transluminal access to a distal portion of the branch vessel is possible. In many instances such access is either impossible (celiac artery, mesenteric arteries, renal arteries) or extremely difficult and/or dangerous (carotid arteries). Still other previous devices do not provide a substantially fluid-tight seal with the branch vessel, thereby partially defeating the purpose of the stent graft (i.e., shielding the repaired portion of the main vessel and/or branch vessel from intravascular fluid pressure).
The stent graft of the present invention, in contrast, addresses these issues. As shown in
After delivery and deployment of bifurcated primary stent graft 100 at the repair site 30, secondary stent graft 300 is then delivered to the repair site and deployed, as illustrated in
Once deployed, incoming fluid flow (i.e., arterial or venous blood flow in the typical deployment scenario) may enter either open end 230 or 240 of bifurcated stent graft 100 and pass through main fluid flow channel 235. Upon reaching the inner open end 270 of internal graft channel 260, the incoming fluid flow divides into a portion continuing to flow in the main fluid flow channel 235 and a portion flowing through the branch fluid flow channel within internal graft channel 260 and through side opening 250. The fluid flow in main channel 235 continues out of bifurcated stent graft 100 and back into the main vessel 20. The branch fluid flow channel comprises a portion of internal graft channel 260 and the interior of secondary stent graft 300, and the branch fluid flow passes into the open inner end 270 of internal graft channel 260, into the open first end 330 of secondary stent graft 300, through secondary stent graft 300 (and therefore through side opening 250), out of open second end 340 of secondary stent graft 300, and into branch vessel 40. Stent graft 300 may preferably be made sufficiently flexible to be bent through angles ranging from about 0° through about 180° while still forming a portion of the branch fluid flow channel. In this way the bifurcated stent graft of the present invention may be used to repair main vessels near where branch vessels leave the main vessel at arbitrarily large angles, even approaching about 180°. To facilitate longitudinal and/or rotational alignment of bifurcated primary stent graft 100 relative to the lumen of the branch vessel, side opening 250 through primary graft sleeve 200 may be made substantially larger than the lumen, thereby increasing the range of positions of bifurcated primary stent graft 100 that nevertheless enable passing secondary stent graft 300 through side opening 250 and into branch vessel 40. It may be desirable for internal graft channel 260 to increase in size with distance from inner open end 270, so that the size of the open inner end of internal graft channel 260 may substantially match the size of secondary stent graft 300 and/or the lumen of branch vessel 40, while the outer open end of internal graft channel 260 may substantially match the relatively enlarged size of side opening 250.
Without departing from inventive concepts disclosed and/or claimed herein, any suitable configuration and/or materials (currently known or hereafter developed) may be employed for stent segments 210, 220, 290, 310, and/or 320. Many suitable configurations for intravascular stents have been developed over the years, as disclosed in the incorporated references and in references cited therein (U.S. Pat. Nos. 5,855,598 and 6,093,203 are of particular note for containing many examples). Such stent configurations may include but are not limited to braids (open-lattice or closely-woven), helical structural strands, sinusoidal structural strands, mesh-like materials, diamond-shaped mesh, rectangular shaped mesh, functional equivalents thereof, and/or combinations thereof. Materials should be sufficiently strong, bio-compatible, hemo9 compatible, corrosion-resistant, and fatigue-resistant, and may include metals, plastics, stainless steels, stainless spring steels, cobalt-containing alloys, titanium-containing alloys, nitinol, nickel-containing alloys, nickel-titanium alloys, composite materials, clad composite materials, other functionally equivalent materials (extant or hereafter developed), and/or combinations thereof. Whatever its construction, a stent graft may typically be delivered transluminally to a vascular repair site with the stent segment in a radially compressed configurations having a delivery diameter sufficiently small to pass through any required vessels to the repair site. Once positioned properly, the stent segment may be radially enlarged to a deployed diameter. The stent segment may be fabricated so that the delivery diameter is achieved through elastic radial compression of the stent segment (maintained during transluminal delivery by a sleeve or equivalent device). Once properly positioned, the sleeve or equivalent device may be removed, thereby allowing the stent segment to expand to its deployed diameter. The deployed diameter may be smaller than the uncompressed diameter of the stent segment, so that residual elastic expanding force exerted by the stent segment may serve to hold the vessel open, fix the stent in place in the vessel, and/or form a substantially fluid-tight seal with the endoluminal surface of the vessel (in conjunction with a graft sleeve). Alternatively, the stent segment may comprise material(s) that undergo plastic deformation. The stent graft may be delivered transluminally with the stent segment having a delivery diameter sufficiently small to allow delivery to the repair site. The stent segment may then be expanded (by an intra-luminal balloon catheter or other functionally equivalent device) to a deployed diameter, and may maintain the deployed diameter due to plastic deformation of the stent segment during expansion. The
expanded stent segment may serve to engage the endoluminal surface of the vessel to hold the vessel open, hold the stent graft in position, and/or form a substantially fluid-tight seal with the vessel. Other methods of delivery and/or deployment may be employed without departing from inventive concepts disclosed and/or claimed herein.
Whatever configuration of stent segment(s) is employed, the stent segment must be adapted to engage the endoluminal surface of the vessel. This may be accomplished by any suitable method (currently known or hereafter developed; for example as disclosed in the incorporated references and in references cited therein), including but not limited to: elastic or plastic expansion; sutures; ligatures; clips; barbs; endoluminal cellular overgrowth; functional equivalents thereof; and/or combinations thereof.
First and second stent segments corresponding to a single graft sleeve of a single stent graft have been shown herein as separate structural elements. Pairs of first and second stent segments (segments 210 and 220, for example, or 310 and 320) may be mechanically connected by a stent coupling member. Three longitudinal wires 215 are shown serving to connect stent segments 210 and 220 of primary stent graft 100, while longitudinal wires 315 are shown serving to connect stent segments 310 and 320 in
Without departing from inventive concepts disclosed and/or claimed herein, any suitable configuration and/or materials (currently known or hereafter developed) may be employed for primary graft sleeve 200, partition 280, and/or graft sleeve 300. Such sleeve materials may include, but are not limited to: continuous sheets; interwoven textile strands; multiple filament yarns (twisted or un-twisted); monofilament yarns; PET (Dacron), polypropylene, polyethylene, high-density polyethylene, polyurethane, silicone, PTFE, polyolefins, ePTFE, biologically-derived membranes (such as swine intestinal submucosa), functional equivalents thereof, and/or combinations thereof. The graft sleeve may be delivered at the size appropriate for deployment at the repair site, or may be a smaller size and stretched (plastically deformed) at the repair site to the desired deployed size. Graft sleeves are shown herein outside the corresponding stent segment, but the stent segment may equivalently be outside the corresponding graft sleeve. The graft sleeve and corresponding stent segment(s) may be operatively coupled by any suitable method (currently known or hereafter developed), including but not limited to: sutures, ligatures, clips, barbs, adhesives (silicone, siloxane polymer, fluorosilicones, polycarbonate urethanes, functional equivalent thereof, and/or combinations thereof); functional equivalent thereof, and/or combinations thereof. Alternatively, a graft sleeve and corresponding stent segment(s) may comprise a single integral structure. Without departing from inventive concepts disclosed and/or claimed herein, an end of a graft sleeve and the corresponding stent segment may extend longitudinally substantially equally (as shown in the Figures), the graft sleeve may extend longitudinally beyond the stent segment, or the stent segment may extend longitudinally beyond the graft sleeve. Without departing from inventive concepts disclosed and/or claimed herein, a graft sleeve may be adapted to engage an endoluminal vessel surface by endoluminal cellular invasion (by manipulation of graft sleeve porosity or other equivalent technique), thereby substantially fixing the graft sleeve to the vessel and forming a substantially fluid-tight seal therewith.
In the present invention, a substantially fluid-tight seal between a stent graft and a vessel may be achieved by adapting the graft sleeve and corresponding stent segment to engage the endoluminal surface of the vessel. This may be readily achieved by using a graft sleeve outside the stent segment. Expansion of the stent segment (either elastic or plastic) may then serve to press the graft sleeve against the inner vessel surface, thereby forming the substantially fluid-tight seal. For a graft sleeve inside the stent segment, a substantially fluid-tight connection between the stent segment and the graft sleeve is required, thereby resulting in a substantially fluid-tight seal between the graft sleeve and vessel surface when the stent segment engages the vessel surface. Without departing from inventive concepts disclosed and/or claimed herein, many other functionally equivalent configurations (currently known or hereafter developed) may be contrived for operatively coupling a graft sleeve to a stent segment, and for engaging an endoluminal surface of the vessel and forming a substantially fluid-tight seal therewith.
Internal graft channel 260 and partition 280 may be formed in a variety of functionally equivalent ways without departing from inventive concepts disclosed and/or claimed herein. As shown in
The primary graft sleeve 200 shown in
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
Claims
1. A stent graft comprising:
- a primary stent construct;
- a primary graft coupled to the primary stent construct, the primary graft extending between a first end and a second end, the primary graft having an outer surface and an inner surface, the inner surface of the primary graft defining a primary fluid flow channel between the first end and the second end, the primary graft having a side opening into the primary flow channel between the first end and the second end; and
- a secondary graft coupled lengthwise along an outer surface of the primary graft, the secondary graft defining an external graft channel extending along the outer surface of the primary graft such that the primary graft channel and the external graft channel extend in a common longitudinal direction, the external graft channel defining an external fluid flow channel communicating with the primary fluid flow channel through the side opening in the primary graft, the secondary graft including an end at least partially opening in a common direction with the first end or the second end of the primary graft, the end of the secondary graft being configured to couple with a branch member having a branch fluid flow channel to connect the branch fluid flow channel of the branch member to the primary fluid flow channel of the primary graft member through the side opening in the primary graft.
2. The stent graft of claim 1, further comprising a secondary stent construct coupled to the secondary graft to maintain patency of the external graft channel.
3. The stent graft of claim 2, wherein the secondary stent construct extends along a majority of the secondary graft.
4. The stent graft of claim 1, further comprising a secondary stent construct configured to maintain patency of the end of the secondary graft that is configured to couple with a branch member.
5. The stent graft of claim 1, wherein the secondary graft defines a raised surface relative to the outer surface of the primary graft.
6. A bifurcated stent graft comprising:
- one or more stents;
- a primary graft coupled to the one or more stents having a first end and a second end forming a primary fluid flow channel; and
- one or more external graft channels formed by graft material coupled to an outer surface of the primary graft configured to communicate with the primary fluid flow channel through a side opening in the primary graft, the one or more external graft channels including an end at least partially opening in a common direction with the first end or the second end of the primary graft configured to accept a branch member and connect the branch member to the primary fluid flow channel through the side opening in the primary graft.
7. The bifurcated stent graft of claim 6, wherein the one or more external graft channels form a second fluid flow channel that includes at least portion that extends along the outer surface of the primary graft.
8. The bifurcated stent graft of claim 7, wherein the one or more external graft channels include a stent portion arranged at or adjacent to the end of the one or more external graft channels.
9. The bifurcated stent graft of claim 8, wherein an outer surface of the one or more external graft channels is spaced apart from the outer surface of the primary graft. The bifurcated stent graft of claim 9, wherein the stent portion maintains the second fluid flow channel spaced apart from the outer surface of the primary graft.
11. The bifurcated stent graft of claim 6, wherein the one or more stents include a first stent arranged at or adjacent to the first end of the primary graft and a second stent arranged at or adjacent the second end of the primary graft, the first stent and the second stent being configured to form substantially fluid-tight seals with an endoluminal surface of a vessel near the first end and the second end of the primary graft by engagement of the first stent and the second stent with the vessel.
12. The bifurcated stent graft of claim 6, wherein the branch member is configured to communicate with a fluid volume that is substantially isolated from intravascular volumes both upstream and downstream of the primary graft.
13. The bifurcated stent graft of claim 6, wherein the branch member includes a proximal end configured to form a substantially fluid-tight seal within the one or more externa channels and a distal end configured to form a substantially fluid-tight seal within a branch vessel.
14. The bifurcated stent graft of claim 6, wherein the one or more external graft channels includes at least two external graft channels arranged at different longitudinal and circumferential positions along the outer surface of the primary graft.
15. The bifurcated stent graft of claim 14, wherein the at least two external graft channels includes a first external graft channel having an end at least partially opening in a common direction with the first end or the second end of the primary graft and a second external graft channel having an end at least partially opening in a common direction with the first end or the second end of the primary graft, wherein the opening of the first external graft channel is spaced apart from the second external graft channel circumferentially about the outer surface of the primary graft.
16. The bifurcated stent graft of claim 9, wherein the first external graft channel is spaced apart from the second external graft channel longitudinally along the outer surface of the primary graft.
17. A bifurcated stent graft comprising:
- a primary stent graft coupled to the one or more stents having a first end and a second end forming a primary fluid flow channel; and
- two or more secondary stent grafts formed by graft material coupled to an outer surface of the primary stent graft, each of the two or more secondary stent graft being spaced apart from one another circumferentially about the outer surface of the primary graft and configured to communicate with the primary fluid flow channel through a corresponding side opening in the primary graft to accept a branch member and connect the branch member to the primary fluid flow channel through the side opening in the primary graft.
17. The bifurcated stent graft of claim 17, wherein the two or more secondary stent grafts are spaced apart longitudinally along the outer surface of the primary stent graft.
18. The bifurcated stent graft of claim 17, wherein the two or more secondary stent grafts each form secondary fluid flow channels that include at least portion of each of the secondary fluid flow channels that extend along the outer surface of the primary stent graft.
19. The bifurcated stent graft of claim 18, wherein the two or more secondary stent grafts each include a stent portion arranged at or adjacent to the end of the secondary stent grafts.
20. The bifurcated stent graft of claim 19, wherein an outer surface of each of the secondary stent grafts are spaced apart from the outer surface of the primary stent graft.
21. An endoprosthesis for repair of a damaged portion of an aorta, the endoprosthesis comprising:
- a primary graft coupled to the a first stent at a first end of the primary graft and a second stent arranged at a second end of the primary graft, the primary graft having an outer surface configured to engage a tissue wall of the aorta and an inner surface configured to define a primary fluid flow lumen between the first end and the second end, the primary graft having a side opening into the primary flow lumen between the first end and the second end; and
- an external graft channel extending along the outer surface of the primary graft, defining an external fluid flow channel communicating with the primary fluid flow channel through the side opening in the primary graft extending substantially in a common longitudinal direction as the primary flow lumen, the secondary graft including an end section at least partially opening in a common direction with the first end or the second end of the primary graft; and
- a branch member having a branch fluid flow channel configured to engage the end section of the external graft channel and to connect the branch fluid flow channel of the branch member to the primary fluid flow channel of the primary graft member through the side opening in the primary graft.
22. The endoprosthesis of claim 21, wherein the primary graft is configured to substantially isolate the damaged portion of the aorta from intravascular fluid pressure and the branch member is configured to allow blood flow to a branch vessel.
23. The endoprosthesis of claim 21, wherein the branch member is configured to extend within the external graft channel external to the primary flow lumen.
24. The endoprosthesis of claim 21, wherein the branch member is configured to engage with the section of the external graft channel in a fluid tight arrangement.
25. A method of deploying a stent graft within a vessel, the method comprising:
- arranging an endoprosthesis within the vessel, the endoprosthesis including a primary stent construct, a primary graft coupled to the primary stent construct, the primary graft extending between a first end and a second end, the primary graft having an outer surface and an inner surface, the inner surface of the primary graft defining a primary fluid flow channel between the first end and the second end, the primary graft having a side opening into the primary flow channel between the first end and the second end, and a secondary graft coupled lengthwise along an outer surface of the primary graft, the secondary graft defining an external graft channel extending along the outer surface of the primary graft such that the primary graft channel and the external graft channel extend in a common longitudinal direction, the external graft channel defining an external fluid flow channel communicating with the primary fluid flow channel through the side opening in the primary graft, the secondary graft including an end at least partially opening in a common direction with the first end or the second end of the primary graft; and
- engaging a first end portion of a branch member with the end of the secondary graft, the branch member having a branch fluid flow channel to connect the branch fluid flow channel of the branch member to the primary fluid flow channel of the primary graft member through the side opening in the primary graft; and
- arranging a second end portion of the branch member within a branch vessel extending from the vessel.
26. The method of claim 25, wherein the primary graft is configured to substantially isolate the damaged portion of the aorta from intravascular fluid pressure and the branch member is configured to allow blood flow to a branch vessel.
27. The method of claim 25, wherein the branch member is configured to extend within the external graft channel external to the primary flow lumen.
29. The method of claim 25, wherein the branch member is configured to engage with the section of the external graft channel in a fluid tight arrangement.
Type: Application
Filed: Nov 20, 2020
Publication Date: Mar 11, 2021
Inventor: Stephen F. Quinn (Eugene, OR)
Application Number: 17/100,345