Expandable Guide Sheath

Abstract

A system for delivering a medical implant has an expandable guiding sheath that can be locally expanded and stretched to allow passage of a delivery catheter and implant, such as a prosthetic heart valve secured to a balloon catheter, and the expandable sheath can be configured such that the local expansion is proportional to the local surface stretch.

Description

[Technical Field]

[0001] This application claims priority to U.S. Provisional Patent Application No. 62 / 740,690, filed October 3, 2018, which is incorporated herein by reference in its entirety.

[0002] The present invention relates to systems and methods for delivering and deploying medical implants, such as prosthetic heart valves, and more particularly to methods and devices that use an expandable sheath to accommodate implant delivery. [Background technology]

[0003] Catheter systems, such as treatment, delivery, and / or deployment catheters, are used to treat patients internally. For example, delivery catheter systems are used to deliver and deploy prosthetic devices, such as prosthetic heart valves, to locations within the body. Prosthetic heart valves can be delivered to treatment sites within a patient (e.g., aortic, mitral, tricuspid, and / or pulmonary valve locations) using transcatheter techniques.

[0004] Introducing sheaths can be used to safely introduce delivery devices, such as delivery catheters, into a patient's vasculature using a variety of approaches, such as a transfemoral approach via the femoral artery. Such introducing sheaths protect local tissue and facilitate the introduction of the delivery catheter into the patient. A typical introducing sheath generally has an elongated sleeve that is inserted into the vasculature and a housing that remains outside the patient's body, the housing containing one or more sealing valves that minimize blood loss out of the sheath when a delivery device is advanced into the patient through the elongated sleeve and housing.

[0005] Conventional methods of accessing a vessel such as the femoral artery prior to the introduction of a delivery system involve dilating the vessel using multiple dilators or sheaths of progressively increasing diameter. This repeated insertion and vessel dilation can increase the amount of time the procedure takes and the risk of damage to the vessel.

[0006] Radially expanding access sheaths are known in the art. Such sheaths may have complex mechanisms, such as ratcheting mechanisms, that maintain the sheath in an expanded configuration when a device with a diameter larger than the original diameter of the sheath is introduced. Other sheaths are capable of elastic deformation and temporary elastic radial expansion in response to outward pressure generated by a delivery catheter or other device passing through the sheath. Some of these sheaths elastically deform / radially expand in a localized area when a wider portion of the delivery catheter is inserted, and then return to a smaller (e.g., original) diameter once this wider portion of the delivery system has passed that particular portion of the sheath. However, localized radial expansion can cause a change in the overall length of the sheath, which can alter the position of multiple portions of the sheath within the patient's vasculature. Furthermore, current expandable sheath technology cannot alleviate compression across the entire length of the delivery catheter body and may actually increase sheath compression forces as the sheath expands. These compressive forces may interfere with advancement of the catheter / implant through the sheath and / or may require high delivery forces to advance the catheter / implant through the sheath. Summary of the Invention [Problem to be solved by the invention]

[0007] There is a need for a delivery sheath that can locally radially expand to accommodate a delivery catheter / device without causing a change in the overall length of the sheath, and there is also a need for a delivery sheath that relieves compression on a larger delivery catheter as it is threaded through the sheath body. The present invention meets these needs. [Means for solving the problem]

[0008] The present invention provides systems, devices, and methods for accessing a patient's body using an access sheath and a delivery / deployment / treatment catheter, such as may be desirable during a heart valve implantation procedure, such as transcatheter heart valve delivery.

[0009] In one embodiment, a sheath is configured that can locally stretch in response to and proportional to a corresponding local radial expansion, and / or vice versa, i.e., locally radially expand in response to and proportional to a corresponding local surface stretch. The local surface stretching allows the overall length of the sheath to remain constant during the local radial expansion. The local radial expansion can create a larger diameter lumen that can accommodate larger structures and can also reduce compressive forces on catheters and / or implants passing through the sheath. Preferably, the local surface stretching can occur directly in response to the local radial expansion and without the application of any other force (other than the force causing the local radial expansion). Preferably, the local radial expansion can occur directly in response to the local surface stretching and without the application of any other force (other than the force causing the local surface stretching).

[0010] The sheath of the present invention may exhibit a negative Poisson's ratio. In prior art expandable sheaths, the act of passing a delivery catheter through the sheath causes radial expansion of the sheath, but also causes an increase in compressive force on the delivery catheter by the sheath, which typically requires a high insertion force to advance the catheter through the sheath. In contrast, the sheath of the present invention has a negative Poisson's ratio, and radial expansion of the sheath (which may be caused by longitudinal tensile force and / or radial expansion force) results in a decrease in the compressive force from the sheath due to sheath expansion. This decrease in compressive force during radial expansion reduces the sheath's internal resistance to advancement of the catheter / implant through the sheath. This may reduce the overall force required to introduce and advance the delivery catheter / implant through the sheath, facilitating a less complex procedure and reducing the forces exerted on the patient's anatomical structures during the procedure.

[0011] Preferably, the sheath can be configured such that radial expansion and stretching are proportional and coordinated with one another, such that radial expansion is proportional to local surface stretching and / or local surface stretching is proportional to radial expansion. Radial expansion can be caused in whole or in part by a local longitudinal tensile force along the sheath. For example, advancing a catheter through the sheath can cause a local longitudinal tensile force on the sheath, which can cause local surface stretching, which in turn can cause local radial expansion. Stretching can be caused in whole or in part by a radially outward force along the length of the sheath. For example, expansion of a device within the sheath can cause a local radial expansion force on the sheath, which can cause radial expansion, which in turn can cause local surface stretching.

[0012] Sheaths according to the present invention may include a stent-like frame that provides desired expansion / stretching / Poisson's ratio performance, and the stent-like frame may provide improved kink resistance / performance even at very small diameters and very small wall thicknesses.

[0013] The sheath of one embodiment of the present invention includes an insertion body and a hub. The insertion body is elongated and configured to be advanced into a patient, such as into the femoral artery. The sheath may include an outer elastic layer, an inner lining layer, and a stent-like frame between the inner and outer layers, and may further include an adhesive to secure the layers / frame together. The stent-like frame may be configured to locally radially expand in response to localized surface stretching of the stent-like frame and / or to locally stretch in response to localized radial expansion. The sheath may be configured to slidingly receive a catheter (such as a delivery catheter with an implant mounted therein) and to locally radially expand and stretch in response to the catheter being slidingly advanced through the sheath.

[0014] The stent-like frame of the sheath may have a plurality of circumferential links, a plurality of nodes, and a plurality of longitudinal links. A plurality of ring-shaped elements extend around the periphery of the stent-like frame, each ring-shaped element having circumferential links that alternate with the nodes and extend circumferentially around the ring-shaped element. Adjacent ring-shaped elements may be secured to one another by longitudinal links that extend longitudinally between and connect the nodes of adjacent ring-shaped elements. When the stent-like frame is in an unexpanded and unstretched configuration, the longitudinal and circumferential links have a more curved shape, and when the stent-like frame is in an expanded and stretched configuration, the longitudinal and circumferential links have a less curved shape.

[0015] Expansion of the stent-like frame can at least partially straighten the circumferential links, which at least partially rotate the nodes, which at least partially straighten the longitudinal links. Elongation of the stent-like frame can at least partially straighten the longitudinal links, which at least partially rotate the nodes, which at least partially straighten the circumferential links.

[0016] A system for delivering a prosthetic heart valve into a patient's native annulus according to one embodiment of the present invention includes a guide sheath, a delivery catheter configured to be advanced through an inner vessel of the patient, and an implant secured relative to the delivery catheter.

[0017] A method of the present invention for treating a patient, such as by delivering a cardiac valve repair implant into the patient's heart, may include the steps of: forming an incision in the patient leading from an access site on the patient's outer surface into a first blood vessel; advancing a distal end of an access sheath through the incision and into the first blood vessel, the access sheath being configured to locally radially expand and locally stretch when the catheter and implant are advanced through the access sheath; advancing a guidewire from the access site through the incision, the access sheath, and the first blood vessel to a location at or adjacent to a treatment site; advancing a distal end of a catheter along the guidewire to the treatment site, the distal end of the catheter including locally expanding and locally superficially stretching the access sheath in response to advancement of the catheter through the access sheath; performing treatment at the treatment site via the catheter; removing the catheter from the patient; removing the guidewire from the patient; removing the access sheath from the patient; and closing the incision. The first blood vessel may be the femoral artery, and the distal end of the access sheath may be advanced into the aorta. The treatment site may be at or adjacent to a heart valve. The catheter may be a delivery catheter having a prosthetic heart valve at its distal end. Localized stretching of the access sheath may be caused by longitudinal tension applied to the access sheath by advancement of the catheter, and localized expansion of the access sheath is caused by localized stretching of the access sheath. The systems, devices, and / or methods of the present invention may be used in a variety of catheter-based procedures, including minimally invasive and percutaneous procedures. In some embodiments, these methods / systems / devices may involve transapical delivery through a small incision in the chest. In other embodiments, these methods / systems / devices may be utilized in transatrial procedures. In still other embodiments, these methods / systems / devices may be utilized in percutaneous procedures, such as via one or more catheters within a patient's arterial system (e.g., through the femoral or brachial arteries).

[0018] It should be understood that each of the elements disclosed herein can be used with any and all elements disclosed herein, even if that particular combination of elements may not be explicitly shown in the drawings herein. In other words, based on the description of a particular device, one skilled in the art should have little difficulty combining the features of any two such devices. It should therefore be understood that many of these elements are interchangeable, and the present invention encompasses all permutations thereof.

[0019] Other objects, features and advantages of the present invention will become apparent from a consideration of the following detailed description. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a side view of a system for delivering a device to a location within a patient via a catheter, according to one embodiment of the present invention. [Figure 2A] FIG. 1 is a side view of a sheath according to one embodiment of the present invention. [Figure 2B] FIG. 2 is an end view (cross section) of a sheath according to one embodiment of the present invention. [Figure 3A] FIG. 1 is a side view of a system during transcatheter device delivery through a sheath, according to one embodiment of the present invention. [Figure 3B] FIG. 1 is a side view of a system during transcatheter device delivery through a sheath according to an embodiment of the present invention. [Figure 3C] FIG. 1 is a side view of a system during transcatheter device delivery through a sheath according to an embodiment of the present invention. [Figure 4A] 1 is a perspective view of a stent-like frame according to one embodiment of the present invention. [Figure 4B] 1 is a perspective view of a stent-like frame according to one embodiment of the present invention. [Figure 5A] FIG. 4C is a side view of a sheath including a stent-like frame such as the frame shown in FIGS. 4A and 4B. [Figure 5B]FIG. 5B is a side view of the sheath of FIG. 5A with a delivery catheter advanced therethrough. [Figure 6A] 10A-10C illustrate operational features of a node portion of a stent-like frame for use with a sheath, according to one embodiment of the present invention. [Figure 6B] 10A-10C illustrate operational features of a node portion of a stent-like frame for use with a sheath according to one embodiment of the present invention. [Figure 7A] FIG. 10 shows a stent-like frame portion in an unexpanded state, according to one embodiment of the present invention. [Figure 7B] FIG. 10 shows a stent-like frame portion in a partially expanded state, according to one embodiment of the present invention. [Figure 7C] FIG. 10 shows a stent-like frame portion in a fully expanded state, according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] FIG. 1 illustrates a system 10 according to the present invention for delivering and deploying a prosthetic heart valve 12 or other medical device to a desired site within a patient. The system 10 includes a delivery catheter 14 (e.g., a balloon catheter) on which a prosthetic heart valve is advanced through a delivery sheath 16. Typically, the sheath 16 is passed through an incision 18 in the patient and routed into a vessel 22, such as a transfemoral vessel, such that a distal end 24 of the sheath 16 is inserted into the vessel 22. The sheath 16 may include a hub 26 at its proximal end 28, and a hemostatic valve 30 may be housed within the hub 26 to prevent fluid loss through the hub 26. The delivery catheter 14, loaded with the prosthetic valve 12, may be inserted and advanced within the sheath 16 to advance and position the prosthetic device 12 at a desired treatment location within the patient. A sheath 16 according to one embodiment of the present invention is illustrated in FIGS. 2A-2C. The sheath 16 has a distal end 24 and a proximal end 28, with the proximal end 28 having an elongated insertion body 32 and a hub 26. A sheath lumen 34 extends through the sheath 16 from the proximal end 28 to the distal end 24.

[0022] The elongate insertion body 32 of the sheath 16 may be formed from a multi-layer structure. In the particular embodiment shown, a low-friction liner 36 (PTFE, FEP, PEBAX, etc., which may be blended with a lubricious material, such as PEBAX with PROPEL®) is provided and defines the wall of the sheath lumen 34. The low-friction liner 36 facilitates the advancement of catheters and other devices through the sheath 16. A layer of adhesive 38, such as a tie-layer adhesive, may be provided. A stent-like frame 40 may provide desired expansion / contraction characteristics. An elastomeric jacket 42 may surround the sheath exterior. With respect to the liner 36, adhesive 38, stent-like frame 40, and jacket 42, it should be noted that an insertion body 32 according to the present invention may include all, none, or any combination of these elements. For example, the stent-like frame 40 may be used, but the inner liner 36, adhesive 38, and / or outer jacket / liner 42 may not be used. The insertion body 32 is generally configured such that localized surface length expansion in the wall portions of the insertion body 32 allows for localized radial expansion while still maintaining a constant overall length by allowing for localized strain in the wall portions caused by radial expansion. Preferably, the insertion body 32 has a length 44 sufficient to allow the sheath distal end portion 24 to extend to a desired location within the patient (e.g., a desired location within a blood vessel, such as the ascending aorta accessed via a transfemoral approach), while the hub 26 remains outside the patient.

[0023] Lengths 44 within the scope of the present invention include 12-18 inches (30-45 cm), 14-16 inches (35-40 cm), etc. (for transfemoral approaches), although other lengths are also within the scope of the present invention depending on the particular application. The insertion body 32 may have an initial outer diameter 46A small enough to easily fit through the access point, target vessel (e.g., the aorta), and any intervening body features (e.g., the femoral artery). Initial (unexpanded) outer diameters within the scope of the present invention include 3-8 mm for transfemoral procedures, although other outer diameters are also within the scope of the present invention depending on the particular application. During expansion, the outer diameter of the sheath may optionally expand by 20% (or more), 30% (or more), 40% (or more), or even 50% (or more).

[0024] 3A-3C illustrate a sheath 16 according to the present invention having an insertion body portion 32 that expands locally both radially and longitudinally during catheter advancement while maintaining the same overall insertion body length 44. As shown in FIG. 3A, prior to advancement of the catheter and implant through the sheath 16, the insertion body portion 32 of the sheath 16 has a diameter 46 and an overall length 44. As shown in FIG. 3B, when a delivery catheter 14 with an attached implant 12 (e.g., a prosthetic heart valve) is advanced through the sheath 16, the insertion body portion 32 radially expands locally around the implant 12. As the sheath / insertion body portion 32 expands, the compressive force of the sheath / insertion body portion is relieved due to the negative Poisson's ratio of the stent-like frame 40 during radial expansion. This relief of compressive force results in less resistance from the sheath to advancement of the catheter / implant through the sheath.

[0025] The localized radial expansion induces contour distortions along the outer surface of the insertion body portion 32, such as the "shoulders" 48 formed on the insertion body portion 32 on each side of the implant 12. These surface distortions would result in overall sheath shortening if not accompanied by localized surface stretching of the sheath's outer surface. As shown in FIG. 3B, the localized surface stretching results in a surface distance or contour length 50 (i.e., the distance along the surface of the insertion body portion) that is longer than the overall "liner" length 44 of the sheath insertion portion 32. As a result, the overall length 44 of the sheath insertion portion 32 remains constant as the sheath surface's surface distance / contour length 50 changes to accommodate the radial expansion of the sheath 16. As shown in FIG. 3C, after the catheter and implant are removed from the sheath 16, the insertion portion 32 returns to its original diameter.

[0026] 4A-4B show a stent-like frame 40 for use with a sheath 16 according to one embodiment of the present invention. The stent-like frame 40 includes a series of circumferentially extending links 50 having circumferential link ends 52 secured to nodes 54 to form ring-shaped elements 55 extending radially around the stent-like frame, and longitudinally extending links 56 having longitudinal link ends 58 secured to nodes 54 to connect adjacent ring-shaped elements 55. Each node is secured to four links, with two circumferential link ends 52 secured to opposite sides of each node 54 and two longitudinal link ends 58 secured to opposite sides of each node 54. This particular configuration of the nodes 54 and links 50, 52 results in a frame 40 in which localized radial expansion inherently induces a corresponding localized surface length elongation, which returns the stent-like frame 40 to its original surface length when the stent-like frame 40 returns to its original diameter. And vice versa. This particular configuration of the nodes 54 and links 50, 52 results in a frame 40 in which localized radial expansion inherently induces a corresponding localized surface length elongation, which returns the stent-like frame 40 to its original diameter when the stent-like frame 40 returns to its original surface length.

[0027] The embodiment of Figures 4A-4B is merely one example of a specific geometry in accordance with the present invention. It should be noted that other stent-like frame configurations that achieve the desired negative Poisson's ratio are also within the scope of the present invention. Additionally, the stent-like frames of the present invention may be formed from a variety of materials. For example, frame 40 may be formed from a memory material, such as nitinol, that can locally expand / stretch the sheath in response to outward pressure caused by the catheter and implant being advanced through the sheath, and then return the sheath to its original diameter / local surface length when the catheter / implant is released from the sheath.

[0028] 5A and 5B show the insertion portion 32 of the sheath 16 including a stent-like frame 40, such as that shown in FIGS. 4A-4B. The other layers in the particular embodiment shown (e.g., inner liner 36, elastomeric jacket 42, etc.) are relatively transparent to allow the frame 40 to be seen. As shown in FIG. 5B, as the delivery catheter 14 and implant 12 are advanced through the sheath 16, the insertion portion 32 and stent-like frame 40 locally deform (including local radial expansion and stretching) to accommodate the catheter 14 and implant 12, while maintaining the overall length of the sheath.

[0029] The operational characteristics of the general node-and-link design of the present invention involve specific interactions between each link and node. As shown in FIG. 6A, prior to localized expansion and stretching, circumferential links 50 and longitudinal links 56 have a pronounced curvature. When radially outward or other forces induce radial expansion, this radial expansion stretches circumferential links 50 to a less curved / straightened configuration. As circumferential links 50 stretch and straighten, circumferential link ends 52 transmit a force to nodes 54, inducing a rotational moment on nodes 54. This rotational moment rotates nodes 54 through an angle 60, which in turn transmits the rotational moment through nodes 54 to longitudinal link ends 58, causing them to rotate and thus at least partially straighten longitudinal links 56. As shown in FIG. 6B, this at least partial straightening of longitudinal links 56 results in a localized surface stretching of the stent structure. Similarly, when a longitudinal tensile force or other stretch-inducing force causes a localized surface stretch, the surface stretch causes longitudinal links 56 to stretch to a less curved / straighter configuration. As longitudinal links 56 stretch and straighten, longitudinal link ends 58 transmit a force to nodes 54, inducing a rotational moment on nodes 54. This rotational moment causes nodes 54 to rotate through angle 60, which in turn transmits the rotational moment through nodes 54 to circumferential link ends 52, causing them to rotate and thus at least partially straighten circumferential links 50. As shown in FIG. 6B, the at least partial straightening of circumferential links 50 causes localized radial expansion of the stent structure.

[0030] Note that the angle 60 through which the node is rotated may be relatively large: for example, the angle could be between 30 and 60 degrees, between 30 and 90 degrees, 30 degrees (or more), 45 degrees (or more), 60 degrees (or more), or even 90 degrees (or more).

[0031] A particular stent-like frame section 70, as shown in Figures 7A-7C, includes longitudinal links 72 having narrow central portions 74 and wide end portions 76 where the links are fixed relative to nodes 78. Similarly, this particular stent-like frame section 70 includes circumferential links 82 having narrow central portions 84 and wide end portions 86 where the links are fixed relative to nodes 78. This combination of narrow central portions and wide end portions makes it easier to bend the links 72, 82 into a straighter shape at their central portions 74, 84 and more difficult to bend the links 72, 82 at or adjacent their end portions 76, 86 where they are fixed relative to nodes 78. As a result, when the links are straightened, it is easier to transmit rotational moments to or from the nodes 78 via the links 72, 82.

[0032] Nodes 78 according to the present invention may include internal cutouts, such as the circular cutouts 88 shown in Figures 7A-7C, which reduce the mass of the nodes 78 and, in turn, the entire stent frame. The reduced node mass reduces the rotational moment of inertia of each node 78, which makes it easier to rotate each node 78 and transfer rotational moment from the circumferential links 82 to the longitudinal links 72 and vice versa.

[0033] In FIG. 7A , the stent-like frame 40 is shown in a pre-expanded, pre-stretched configuration. Note that the stent-like frame can be formed in a variety of ways, such as by laser cutting or other cutting from a tube (e.g., a metal tube such as a Nitinol tube). As shown in FIG. 7B , when a portion of the stent-like frame is expanded, straightening of the circumferential links 82 rotates the nodes 78, thereby bending the longitudinal links 72 into a straighter configuration. Similarly, as shown in FIG. 7B , when a portion of the stent-like frame is stretched, straightening of the longitudinal links 72 rotates the nodes 78, thereby bending the circumferential links 82 into a straighter configuration. As shown in FIG. 7C , when fully expanded, the nodes 78 are further rotated, and the circumferential links 82 and longitudinal links 72 are nearly completely straight, resulting in a combination of local radial expansion and proportional local surface stretching.

[0034] Various approaches for treatment involving advancing a catheter into position through a sheath are within the scope of the present invention. One preferred approach (e.g., for aortic valve treatment) is a transcatheter approach via the femoral artery. This method may also include the deployment of a transcatheter aortic valve replacement (TAVR), which may also be performed using the same transcatheter approach.

[0035] In one example of a procedure according to the present invention for deploying a prosthetic aortic heart valve according to the present invention, femoral artery access is obtained through an access sheath according to the present invention sized for use in a TAVR procedure. An incision is made in the patient leading to an internal blood vessel, such as the femoral artery. With the hub positioned outside the patient's body adjacent the incision / access site, the distal end of the access sheath is advanced through the incision and femoral artery to a desired location within the aorta. A guidewire is advanced from the femoral access site through the aortic arch and into the patient's left ventricle. The steerable shaft of the imaging catheter and / or delivery catheter can be advanced over the guidewire, such as by standard over-the-wire techniques, to advance the distal end of the device to the target location. For example, the device may have a guidewire lumen. Echo and / or fluoroscopic and / or other visualization techniques may be utilized, along with electrophysiological 3D mapping techniques. Treatment and implant deployment may then be performed, such as by deploying the prosthetic heart valve at the target location. Once proper deployment is confirmed, the catheter may be removed from the patient, the guidewire may be removed from the patient, the sheath may be removed from the patient, and the incision may be closed, such as with sutures.

[0036] It should be noted that each embodiment and each element thereof disclosed herein may be used with any other embodiment and each element thereof disclosed herein.

[0037] Any dimensions given are examples, and devices according to the invention may have dimensions outside of those particular values ​​and ranges. The dimensions and shape of a device and its elements are determined by its particular application.

[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. In order to facilitate review of the various embodiments of the present disclosure, the following explanations of terms are provided.

[0039] The singular forms "a," "an," and "the" include plural referents unless the context clearly indicates otherwise. The term "or" refers to one element or a combination of two or more of the listed alternative elements, unless the context clearly indicates otherwise.

[0040] The term "comprises" means "has." For example, a device that includes or comprises A and B encompasses A and B, but may optionally include C or other components other than A and B. Furthermore, a device that includes or comprises A or B encompasses A or B or A and B, and optionally includes one or more other components, such as C.

[0041] The term "subject" refers to both human and other animal subjects. In some embodiments, the subject is a human or other mammal, such as a primate, cat, dog, cow, horse, rodent, sheep, goat, or pig. In certain examples, the subject is a human patient.

[0042] Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure, suitable methods and materials are described below. In case of conflict, the present specification, including language, will control. Furthermore, these materials, methods, and examples are illustrative only and not intended to be limiting.

[0043] It should be noted that various individual features of the processes and systems of the present invention may be described herein in the context of only one exemplary embodiment. A particular selection of a description herein relating to a single exemplary embodiment should not be construed as a limitation that a particular feature is applicable only to the embodiment with which it is described. Any feature described herein is equally applicable, additional, or interchangeable with any or all of the other exemplary embodiments described herein, in any combination, grouping, or configuration. In particular, the use of one reference numeral herein to illustrate, define, or describe a particular feature does not imply that the feature cannot be associated with or considered equivalent to another feature in another drawing or description. Furthermore, if more than one reference numeral is used in a drawing, this should not be construed as limiting this use to only those embodiments or features, but rather that these reference numerals are equally applicable to similar features, or that no reference numeral is used, or another reference numeral is omitted.

[0044] In view of the numerous possible embodiments to which the inventive principles of this disclosure may be applicable, it is to be understood that these illustrated embodiments are merely examples of the invention and should not be construed as limiting the scope of the invention. Rather, the scope of the invention is defined by the appended claims. We therefore claim as our invention all that comes within the scope and spirit of the claims. [Explanation of symbols]

[0045] 10 Systems 12 Artificial heart valves, artificial valves, prosthetic devices, implants 14 Delivery catheter 16 Delivery sheath 18 Incision 22 tubes 24 Sheath distal end 26 Hub 28 Proximal end of sheath 30 Hemostasis valve 32 Elongated insertion body, insertion body portion, sheath / insertion body portion, sheath insertion portion, insertion portion 34 See-through Lumen 36 Low friction liner, inner liner 38 Adhesive 40 Stent-like frame 42 Elastomer jacket, outer jacket / liner 44 Length, total length of insertion body, total length 46 diameter 46A initial outer diameter 48 Shoulder 50 surface distance / contour length, circumferentially extending link, link 52 Circumferential link end, link 54 nodes 55 ring-shaped elements 56 Longitudinal extension link 58 Longitudinal link end 60 angle 70 Stent-like frame part 72 Longitudinal Link 74 Narrow central part 76 Wide end part 78 nodes 82 circumferential links 84 Narrow central part 86 Wide end part 88 Circular notch

Claims

1. 1. A system for delivering a prosthetic heart valve to a patient's native annulus, comprising: a delivery sheath comprising an insertion body and a hub, the insertion body having an outer elastic layer, an inner lining layer, and a stent-like frame between the outer elastic layer and the inner lining layer; the stent-like frame having a plurality of ring-shaped elements and a plurality of longitudinally extending links; each of the plurality of longitudinally extending links has a narrow central portion and a plurality of wide end portions; each of the ring-shaped elements having a plurality of circumferentially extending links interleaved with a plurality of nodes; one longitudinally extending link of the plurality of longitudinally extending links extends between two of the nodes of two adjacent ring-shaped elements; the nodes of a portion of the stent-like frame in the expanded configuration are rotated relative to the nodes of the portion of the stent-like frame in the unexpanded configuration, causing localized radial expansion of the stent-like frame in response to localized surface stretching of the stent-like frame. a delivery sheath; a delivery catheter configured to be advanced through an internal vessel of a patient; an implant fixed relative to said delivery catheter; Equipped with the delivery sheath is configured to slidingly receive the delivery catheter having the implant mounted thereon and to locally radially expand and elongate in response to the delivery catheter having the implant mounted thereon being slidingly advanced through the delivery sheath.

2. 2. The system of claim 1, wherein while the portion of the stent-like frame is in the unexpanded configuration, the longitudinally extending links and the circumferentially extending links have a more curved shape than while the portion of the stent-like frame is in the expanded configuration.

3. 3. The system of claim 2, wherein the node is rotated while the portion of the stent-like frame is in the expanded configuration by more than 30 degrees and less than 90 degrees relative to its position while the portion of the stent-like frame is in the unexpanded configuration.

4. The system of claim 3 , wherein the portion of the stent-like frame in the expanded configuration has a surface that is longer in length than the portion in the unexpanded configuration.

5. The system of claim 4 , wherein the portion of the stent-like frame in the expanded configuration has the same linear length as the portion of the stent-like frame in the unexpanded configuration.

6. 3. The system of claim 2, wherein the node is rotated by more than 30 degrees and less than 60 degrees while the portion of the stent-like frame is in the expanded configuration relative to its position while the portion of the stent-like frame is in the unexpanded configuration.

7. The system of claim 6 , wherein the portion of the stent-like frame has the same linear length while the portion is in the expanded configuration and the unexpanded configuration.

8. The system of claim 7 , wherein the stent-like frame has the same overall linear length while the portion is in the expanded configuration and the unexpanded configuration.

9. The system of claim 1 , wherein each of a plurality of said circumferentially extending links has said narrow central portion and said wide end portions.

10. The system of claim 1 , wherein each of the plurality of nodes has an internal notch.

11. The system of claim 10 , wherein the internal cutout is a circular cutout.

12. The system of claim 1 , wherein ends of two of the circumferentially extending links are fixed to opposite sides of each of the nodes.

13. The system of claim 1 , wherein ends of two of the longitudinally extending links are fixed on opposite sides of each of the nodes.

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