Combined introducer and expandable sheath

Abstract

Disclosed herein is a combined introducer and expandable sheath having an inner member and an outer elastic jacket. The inner member has a radially folded tapered section in an unexpanded state, the tapered section being mechanically unfolded and moved toward the inner wall of the elastic jacket by a medical device moving through the lumen of the inner member. Once the medical device has passed through the expanded lumen of the inner member, the compressed outer elastic jacket returns the expanded inner member to a radially folded unexpanded state. The structure may include a distal region that tapers to a rounded end. The proximal region also tapers to mate with a hemostatic valve housing.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 778,698, filed on December 12, 2018, and entitled “COMBINED INTRODUCER AND EXPANSIBLE SHEATH,” the contents of which are incorporated by reference. Technical Field

[0003] The present application is directed to embodiments of sheaths used with catheter-based techniques to introduce a prosthetic device, such as a heart valve or other implant, into the vasculature of a patient. Background Art

[0004] Intravascular delivery catheter assemblies are used to implant prosthetic devices, such as prosthetic heart valves, in locations in the body that are not easily accessible by surgery or that are desired to be accessed without invasive surgery. For example, aortic, mitral, tricuspid, and / or pulmonary valve prosthetic valves may be delivered to the treatment site using minimally invasive surgical techniques including transcatheter delivery methods.

[0005] A sheath may be used to safely guide a delivery device into a patient's vasculature (e.g., a femoral artery). A sheath typically has an elongated sleeve that is inserted into the vasculature and a housing that contains one or more sealing valves that allow the delivery device to be placed in fluid communication with the vasculature with minimal blood loss.

[0006] Radially expandable intravascular sheaths reduce the overall profile of the sheath to reduce the risk of damaging the vessel. Some radially expandable sheaths have complex mechanisms (such as ratchet mechanisms) that maintain the shaft or sheath in an expanded configuration once a device with a diameter greater than the original diameter of the sheath is introduced. Others may combine elasticity and folding to achieve expandability during the passage of a medical device, and then collapse after the medical device has passed.

[0007] Despite advances in expandable endovascular sheath technology, delivering and / or removing prosthetic devices and other materials to and / or from patients still poses risks to patients. For example, access to blood vessels (such as the femoral artery) remains a challenge due to the relatively large profile of the sheath and delivery system, which can cause longitudinal and radial tearing of the vessel during insertion. Prior to the introduction sheath, conventional methods of accessing blood vessels included dilating the vessel using multiple tapered introducers (also known as dilators) of gradually increasing diameter. This repeated insertion and vessel dilation can increase the amount of time the procedure takes, as well as the risk of damaging the vessel. Repeated insertion and vessel dilation can additionally dislodge calcified plaque within the vessel, creating an additional risk of clots caused by the displaced plaque.

[0008]

[0006] Thus, there remains a need for further improvements in sheaths for delivering intravascular systems for implanting heart valves and other prosthetic devices. Summary of the invention

[0009] The currently disclosed combined sheath and introducer (introducer sheath) includes a round and tapered distal tip, a small inner diameter, and a thick radially folded tapered section extending between the outer diameter and the inner diameter. The introducer sheath has a higher rigidity / durometer than a conventional sheath. Thus, because the introducer sheath will not buckle or bend when inserted into a patient's vascular site, it can be used without a dilator.

[0010] Thus, an exemplary combined introducer and expandable sheath according to the principles described herein may include: an elongated inner member having a plurality of radially folded conical sections extending in a longitudinal direction along a longitudinal axis in an unexpanded state, the inner member defining an inner cavity having an inner diameter; and an elongated outer elastomeric jacket extending at least partially on the inner member and having a spring bias toward the inner cavity of the inner member; wherein the inner member provides sufficient rigidity for a combined introducer and expandable sheath for insertion into a patient's vascular system. The inner member may define a central cavity extending in a longitudinal direction. A plurality of radially folded conical sections may be deployed toward the inner surface of the outer elastomeric jacket to expand the inner diameter of the inner cavity when a medical delivery device is inserted into the cavity. On the one hand, for example, the elongated inner member may be compressed against a portion of the inner surface of the outer elastomeric jacket to expand the inner diameter of the elongated inner member to an expanded configuration for passage of an implant. On the other hand, the inner member is compressible independently of the outer elastomeric jacket at the distal end of the seal.

[0011] The combined introducer and expandable sheath may include a strain relief portion extending distally from the proximal end of the outer elastic jacket. The outer elastic jacket may be attached to the strain relief portion. The inner member may include a tapered and rounded distal end. The inner member may have a fixed position longitudinally relative to the outer elastic jacket. In one aspect, the outer elastic jacket is fused to the inner member.

[0012] The inner cavity can be at least partially defined by the inner surface of the radially folded tapered section in the unexpanded state. The thickness t of the tapered section measured in the unexpanded state is 0.045 inches to 0.07 inches from the inner surface of the tapered section to the outer surface of the tapered section. In some embodiments of the combined introducer and expandable sheath, each radially folded tapered section widens as it extends radially outward. The selected tapered section can be connected to the first circumferentially adjacent tapered section at the internal connection point and connected to the second circumferentially adjacent tapered section at the external connection point. In the unexpanded state, the internal connection point can be positioned adjacent to the inner cavity of the inner member and the external connection point can be positioned adjacent to the outer surface of the inner member. The internal connection point and the external connection point can be thinner than the tapered section of the inner member in the radial direction. In this way, the inner member of the combined introducer and expandable sheath thins and widens along its circumferential travel (traveling). A plurality of outwardly extending gaps may extend radially outwardly from the inner cavity (between adjacent tapered sections), and a plurality of inwardly extending gaps may extend radially inwardly from the outer surface of the inner member. The inwardly and outwardly extending gaps each run at least a portion of the length of the inner member.

[0013] According to the principles described herein, a method for delivering a prosthetic device may include: positioning a combined introducer and expandable sheath within a vascular site of a patient, the combined introducer and expandable sheath comprising an elongated inner member having a plurality of radially folded conical sections extending in a longitudinal direction along a longitudinal axis in an unexpanded state, the inner member defining an inner cavity having an inner diameter; and an elongated outer elastic jacket extending at least partially over the inner member and having a biasing spring directed toward the inner cavity of the inner member; wherein the inner member provides sufficient rigidity for the combined introducer and expandable sheath for insertion into a vascular site; guiding the prosthetic device into the inner cavity of the inner member; advancing the prosthetic device through the inner cavity so that the prosthetic device applies a local radially outward force on the inner surface of the inner member and locally unfolds the plurality of radially folded conical sections of the inner member into an expanded configuration; and after the prosthetic device has passed through the cavity, restoring the inner member to an unexpanded state under the push of the outer elastic jacket. The method may further include positioning the combined introducer and expandable sheath without having performed any prior expansion steps on the vascular site. The plurality of radially folded tapered segments may be deployed toward the inner surface of the outer elastic jacket to expand the inner diameter of the cavity when the medical delivery device is inserted into the cavity. In some embodiments, deploying the plurality of radially folded tapered segments further includes widening the gaps extending inwardly and outwardly between adjacent tapered segments. Deploying the plurality of radially folded tapered segments may further include bending the inner member at a plurality of inner connection points and a plurality of outer connection points. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figures 1A-1C A conventional expandable sheath ( Figure 1C ) and a delivery device for deployment through a sheath ( Figure 1A-1B ) side view.

[0015] Figure 2 A perspective view of a conventional expandable sheath is shown.

[0016] Figure 3A Shown is a cross-section of a combined introducer and expandable sheath in an unexpanded state, according to principles described herein.

[0017] Figure 3B Shows Figure 3A Enlarged cross section of .

[0018] Figure 4 Shown is a cross-section of a combined introducer and expandable sheath in an expanded state, according to principles described herein.

[0019] Figure 5 Shown is an inner member of a combined introducer and expandable sheath according to the principles described herein. DETAILED DESCRIPTION

[0020] The following description of certain examples of the inventive concept should not be used to limit the scope of the claims. Through the following description, other examples, features, aspects, embodiments and advantages will become apparent to those skilled in the art. As will be appreciated, the device and / or method can have other different and obvious aspects without departing from the spirit of the inventive concept. Therefore, the drawings and description should be considered to be illustrative rather than restrictive in nature.

[0021] For the purpose of this description, certain aspects, advantages and novel features of the disclosed embodiments are described herein. The described methods, systems and devices should not be construed as limiting in any way. On the contrary, the present disclosure is directed to all novel and non-obvious features and aspects of the various disclosed embodiments (individually and in various combinations and sub-combinations with each other). The disclosed methods, systems and devices are not limited to any specific aspects, features or combinations thereof, nor do the disclosed methods, systems and devices require the presence of any one or more specific advantages or solutions to problems.

[0022] Unless incompatible therewith, features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein. All features disclosed in this specification (including any attached claims, abstracts and drawings), and / or all steps of any method or process so disclosed may be combined in any combination, except that at least some of such features and / or steps in the combination are mutually exclusive. The invention is not limited to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any attached claims, abstracts and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0023] It should be understood that any patent, publication, or other public material, in whole or in part, that is considered to be incorporated by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other public materials set forth in the present disclosure. Thus, to the extent necessary, the present disclosure expressly set forth herein supersedes any conflicting material incorporated by reference herein. Any material or portion thereof that is considered to be incorporated by reference herein but conflicts with existing definitions, statements, or other public materials set forth herein is incorporated only to the extent that no conflict arises between the incorporated material and the existing public materials.

[0024] As used in the specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly indicates otherwise. Ranges may be expressed herein as from "about" one particular value and / or to "about" another particular value. When such a range is expressed, another aspect includes from a particular value and / or to another particular value. Similarly, when a value is expressed as an approximation by using the antecedent "about", it will be understood that the particular value forms another aspect. It will also be further understood that each endpoint in the range is meaningful whether relative to the other endpoint or independent of the other endpoint.

[0025] "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0026] Throughout the description and claims of this specification, the word "comprise" and variations of the word, such as "comprising and comprises", means "including but not limited to", and is not intended to exclude, for example, other additives, components, integers or steps. "Exemplary" means "an example of..." and is not intended to convey an indication of a preferred or ideal aspect. "Such as" is not used in a limiting sense, but for the purpose of explanation.

[0027] As used herein, the terms "proximal" and "distal" refer to regions of a sheath, catheter, or delivery assembly. "Proximal" means the region closest to the handle of the device, while "distal" means the region farthest from the handle of the device.

[0028] As used herein, the terms "tube" or "tubular" are not meant to limit the shape to a circular cross-section. Instead, a tube or tubular may refer to any elongated structure having a closed cross-section and a lumen extending axially therethrough. A tube may also have some slits or openings selectively located therein - although it will still provide a sufficiently closed structure to contain other components within its lumen(s).

[0029] As described above, current procedures for inserting sheaths to deliver prosthetic devices can damage the vascular site. This is due in part to the use of introducers (also known as dilators), which are rigid, tapered solid rods that can be inserted into the vascular site to gradually widen the site in preparation for the introduction of the sheath. Repeated insertion of these dilators can result in damage to the vascular site and, in some cases, can displace plaque, which can lead to further complications during the procedure. In addition, expandable sheaths are being made in increasingly smaller diameters, which presents challenges for the expansion mechanism to fit into smaller spaces.

[0030] A combined introducer and expandable sheath (hereinafter referred to as the introducer sheath) is disclosed herein. The introducer sheath provides an expandable sheath that can be inserted without the need for a preliminary expansion step using a conventional introducer. The unitary structure acts as both an introducer and a sheath, eliminating the time and risk involved in expanding a vessel. Wide radial folds that extend the wall thickness of the inner member allow for a high degree of expansion. The distal region tapers to a rounded end to facilitate expansion of a vascular site. The proximal region also tapers to mate with a hemostatic valve housing.

[0031] Figures 1A-1CA conventional delivery device 110 and sheath 9 for delivering a prosthetic implant (such as a prosthetic heart valve) to a patient are illustrated. It should be understood that the delivery device 110 described herein is merely exemplary, and other similar delivery systems can certainly be used with the disclosed introducer sheath 10. The delivery device 110 illustrated herein generally includes a steerable guide catheter 114 and a balloon catheter 116 extending through the guide catheter 114. Figure 1A-1B The guide catheter 114 and balloon catheter 116 illustrated in the drawings are adapted to slide longitudinally relative to each other to facilitate delivery and positioning of a prosthetic heart valve at an implantation site in a patient's body. The guide catheter 114 includes a handle portion 120 and an elongated guide tube or shaft 122 ( Figure 1B ).

[0032] Figure 1C A conventional expandable sheath 9 is illustrated for introducing a delivery device 110 and a prosthetic device into a patient's body. The conventional expandable sheath 9 has a generally tubular configuration that defines a central lumen to guide the passage of a delivery system for a prosthetic heart valve. At the proximal end, the expandable sheath 9 includes a hemostatic valve to prevent leakage of pressurized blood. Typically, during use, the distal end of the sheath 9 is passed into a patient's blood vessel (such as a femoral artery) by sliding the lumen of the sheath 9 over a previously inserted introducer (which may have the shape of a rigid tapered rod). The introducer is then removed through the lumen of the sheath 9. The delivery device 110 (and its implant) can then be inserted into the lumen of the sheath 9 through the hemostatic valve and advanced through the patient's vascular system, where the implant is delivered and implanted in the patient's body.

[0033] Typically, as described above, in order to insert a conventional sheath 9 into a patient's blood vessel, an introducer (also referred to as a dilator) must be inserted into the vasculature before the sheath 9. The introducer provides sufficient rigidity to not buckle or bend during insertion, and then a more relaxed conventional sheath 9 can be inserted over the introducer and into the blood vessel. During a conventional procedure, once the sheath 9 is inserted into the patient's blood vessel (before the delivery device 110 is inserted through the sheath 9), the introducer is removed. In accordance with the principles described herein, the combined introducer and expandable sheath has an integral structure that acts as both an introducer and a sheath, thereby eliminating the preliminary steps of dilating the blood vessel site and removing the introducer prior to inserting the delivery device.

[0034] like Figure 2 As shown in FIG. 1 , in one embodiment, a combined introducer and expandable sheath 10 (hereinafter, introducer sheath 10 ) includes an outer resilient jacket 330 extending along a longitudinal axis of the sheath. Figure 3A and Figure 4 A cross section of an introducer sheath 10 is illustrated, wherein the same structure functions as both a sheath and a dilator. Figure 5An embodiment of the inner member of the introducer sheath 10 is shown (without the outer jacket elastomeric 330 for illustrative purposes).

[0035] Figure 3A A cross-section of an introducer sheath 10 in an unexpanded state is illustrated. As illustrated, the introducer sheath 10 includes an outer elastic jacket 330 and an inner member 334 within the elastic jacket 330. In the unexpanded state, the inner member 334 defines an inner cavity 338 having an inner diameter ID. In an exemplary embodiment, the unexpanded inner diameter of the inner member 334 (i.e., the diameter of the inner cavity 338) may be approximately 0.04 inches (a size compatible with a guidewire having an outer diameter of approximately 0.038 inches). In the unexpanded state, the outer diameter OD of the introducer sheath 10 including the elastic jacket 330 may be approximately 0.13 inches to approximately 0.18 inches. In the expanded state (e.g. Figure 4 ), the inner diameter ID (expanded ID) of the inner member 334 may be about 0.28 inches to about 0.33 inches. This high expanded inner diameter ID is imparted by the high inner surface area distributed by the many radial folds; in cross section, the entire circumference of the unexpanded inner surface of the inner member 334 (including the surface within the radial folds) is greater than the circumference of a circle with a diameter of 0.30 inches. In the expanded state, the outer diameter OD of the introducer sheath 10 may be about 0.34 inches to about 0.37 inches.

[0036] In the unexpanded state, the inner member 334 includes a plurality of radially folded tapered sections 342. The inner cavity 338 is at least partially defined by a plurality of inner surfaces 343 of the tapered sections 342. Figure 3A As shown in , each tapered section 342 widens as it extends radially outward (from the inner surface 343 of the tapered section 342 to the outer surface 345 of the tapered section 342). Typically, the thickness t of the tapered section (measured from the inner surface 343 to the outer surface 345 when the introducer sheath 10 is in an unexpanded state) can be in the range of about 0.045 inches to about 0.07 inches. Compared with conventional sheaths that generally have a wall thickness of about 0.010 inches to about 0.020 inches, this thickness is relatively high. This relatively large thickness gives the introducer sheath 10 disclosed herein greater columnar strength to help eliminate the need for an introducer / dilator during the insertion procedure. In addition, compared with current expandable sheaths that utilize pleats as part of the expansion mechanism, the relative thickness of the radial pleats is high. This greater radial pleat thickness allows a very high degree of expansion (a greater difference between the unexpanded outer diameter and the expanded outer diameter), which is conducive to the design of a smaller profile sheath.

[0037] Figure 3A An enlarged portion is shown in Figure 3B In. Figure 3B, a selected tapered segment 347 is connected to a first circumferentially adjacent tapered segment 349 at an inner connection point 359, which is located adjacent to the inner cavity 338 defined by the inner member 334. The same selected tapered segment 347 is connected to a second circumferentially adjacent tapered segment 351 at an outer connection point 361, which is located adjacent to the outer surface 353 of the inner member 334. The connection points 359, 361 are thinner in the radial direction than the tapered segment 342 of the inner member 334, so that the inner member 334 becomes thinner and wider as it travels along its circumference (e.g., as shown in FIG. 1 ). Figure 4 ). Figure 3A As shown in FIG. 3 , in this manner, the inner member 334 defines a plurality of outwardly extending gaps 355 that extend radially outward from the inner cavity 338. Figure 5 As shown in , the outwardly extending gap 355 runs at least a portion of the length of the inner member 334. Figure 3A and Figure 5 As shown in FIG. 1 , a plurality of inwardly extending gaps 357 extend radially inwardly from the outer surface of the inner member 334 and also extend at least a portion of the length of the inner member 334. Each of the outwardly extending gaps 355 and the inwardly extending gaps 357 is at least partially defined by two adjacent tapered sections 342. Figure 4 As shown in FIG. 3 , during expansion, the inner member 334 bends at the inner connection point 359 and the outer connection point 361 to separate the tapered section 342 and widen the inwardly extending gap 357 and the outwardly extending gap 355 .

[0038] Figure 4 A cross section of the introducer sheath 10 in an expanded state is illustrated. As illustrated, when expanded, the elastic jacket 330 thins and the radially folded tapered section 342 of the inner member 334 unfolds toward the elastic jacket 330 to expand / widen the lumen 338. The expansion is provided by inserting a medical delivery device. For example, the device can be a transcatheter heart valve (THV) delivery device, which is provided over a guidewire through the lumen of the inner member 334. As shown in FIG. Figure 4 As illustrated in FIG. 1 , the medical delivery device mechanically pushes open the tapered section 342 of the inner member 334. As the medical device is inserted into the lumen 338 of the inner member 334, the outer elastic jacket 330 also expands to an increased outer diameter. When the medical device is removed, the outer jacket material provides sufficient elasticity to return the folded inner member 334 to an unexpanded / folded state after the THV has passed and provide hemostasis for the passage outside the inner member.

[0039] Figure 5The inner member 334 of the introducer sheath 10 according to the principles described herein is illustrated. As illustrated in its unexpanded / folded state, the inner member 334 is substantially cylindrical and can be extruded to have a proximal bump / taper 346. During the manufacturing process, the proximal bump / taper 346 is conducive to the cooperation of the introducer sheath 10 with a wider hemostatic valve housing. In addition, the ratio of the outer diameter to the inner diameter at the bump / taper 346 area is higher than the ratio of the outer diameter to the inner diameter at other areas along the length of the introducer sheath 10. This higher OD / ID is converted into more wall material (greater wall thickness t), which gives good force transmission along the length of the introducer sheath 10. At the distal end, the inner member 334 can also include a tapered and rounded end 350 to assist the expansion of the vascular system during the introduction of the introducer sheath 10.

[0040] The inner member 334 can be fixed relative to the outer elastic jacket or jacket or can "float" relative to the outer sheath. For example, the inner member 334 and the outer elastic jacket 330 can be attached in a fixed position by, for example, an adhesive or thermal bonding so that they do not move relative to each other or can be connected to each other. For example, the inner member 334 and the outer elastic jacket 330 can be attached at the end 350 of the introducer sheath 10, or they can be attached along a portion of the length of the introducer sheath 10.

[0041] The inner member 334 and the outer elastomeric jacket 330 may be formed independently or in an integral process. If formed independently, the elastomeric jacket 330 may be expanded by known means, the inner member 334 is inserted into the elastomeric jacket 330 and the elastomeric jacket 330 is allowed to contract around the inner member 334. The compressive force of the elastomeric jacket 330 around the inner member 334 may be sufficient to reduce the movement between the elastomeric jacket 330 and the inner member 334, sufficient to function as described herein.

[0042] The material of inner member 334 has considerable column strength, to provide rigidity for elastic jacket 330 for catheter insertion, high lubricity for guide wire and THV to pass through, and high flexibility, so the expansion force is low. For example, inner member 334 can be made of material (such as high-density polyethylene, fluoropolymer, Teflon (polytetrafluoroethylene, Teflon) or other materials). In some embodiments, inner member 334 can have a hardness of about 45D to about 65D. Therefore, introducer sheath 10 provides enough rigidity to be inserted through the skin of the patient and enter the circulatory system. Alternative is to use co-extruded inner member to obtain desired characteristics in the desired position.

[0043] Although the foregoing embodiments of the present disclosure have been described in some detail by way of illustration and example for purposes of clarity and understanding, it will be apparent to those skilled in the art that certain changes and modifications may be made within the spirit and scope of the present disclosure. It is intended that the scope of the invention disclosed herein should not be limited by the specific disclosed embodiments described above, but should be determined only by a fair reading of the following claims.

Claims

1. A combined introducer and expandable sheath comprising: an elongated inner member having a plurality of radially folded tapered sections extending in a longitudinal direction along a longitudinal axis in an unexpanded state, the inner member defining an inner lumen having an inner diameter; an elongated outer resilient jacket extending at least partially over the inner member and having a spring biased toward the inner cavity of the inner member; The thickness of the conical section measured in the unexpanded state is t The inner surface of the tapered section is 0.045 inches to 0.07 inches from the inner surface of the tapered section to the outer surface of the tapered section so that the inner member provides sufficient rigidity for the combined introducer and expandable sheath to be inserted into the vasculature of a patient.

2. The combined introducer and expandable sheath of claim 1, wherein the inner member defines a central lumen extending in the longitudinal direction.

3. A combined introducer and expandable sheath according to claim 1 or 2, wherein the plurality of radially folded tapered sections unfold toward the inner surface of the outer elastic jacket to expand the inner diameter of the inner cavity when a medical delivery device is inserted into the inner cavity.

4. The combined introducer and expandable sheath of claim 1 or 2, further comprising a strain relief portion extending distally from the proximal end of the outer elastic jacket, wherein the outer elastic jacket is attached to the strain relief portion.

5. The combined introducer and expandable sheath of claim 1, wherein the inner member further comprises a tapered and rounded distal tip.

6. A combined introducer and expandable sheath according to claim 1 or 2, wherein the inner member has a fixed position longitudinally relative to the outer elastic jacket.

7. A combined introducer and expandable sheath according to claim 1 or 2, wherein in an unexpanded state, the inner cavity is at least partially defined by the inner surface of the radially folded conical section.

8. A combined introducer and expandable sheath according to claim 1 or 2, wherein the inner member has a hardness of 45D to 65D.

9. A combined introducer and expandable sheath according to claim 1 or 2, wherein each radially folded tapered section widens as it extends radially outward.

10. The combined introducer and expandable sheath of claim 9, wherein a selected tapered segment is connected to a first circumferentially adjacent tapered segment at an inner connection point and to a second circumferentially adjacent tapered segment at an outer connection point.

11. The combined introducer and expandable sheath of claim 10, wherein in an unexpanded state, the inner connection point is positioned adjacent to the inner lumen of the inner member and the outer connection point is positioned adjacent to an outer surface of the inner member.

12. A combined introducer and expandable sheath according to any one of claims 10 or 11, wherein the inner and outer connection points are thinner in a radial direction than the tapered section of the inner member.

13. The combined introducer and expandable sheath of claim 11, wherein the inner member thins and widens as it progresses circumferentially.

14. The combined introducer and expandable sheath of claim 9, further comprising a plurality of outwardly extending gaps extending radially outward from the inner cavity and between adjacent tapered sections, and a plurality of inwardly extending gaps extending radially inward from an outer surface of the inner member.

15. The combined introducer and expandable sheath of claim 14, wherein the inwardly and outwardly extending gaps each run at least a portion of the length of the inner member.

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