Improvements to introducer sheaths

Abstract

The present disclosure relates generally to improved introducer sheaths for insertion into the body to provide endovascular access to various medical devices, to introducer sheaths that can be inserted while providing resistance to frictional forces that otherwise may cause unintentional compression of the outermost layer of the sheath. Embodiments generally include an introducer sheath including a circumferentially continuous elastomeric outer layer, and a support element.

Description

Invention Name

[0001] Improvements to the Introducer Sheath

[0002] Technical Field The present invention relates generally to introducer sheath devices for insertion into the body to provide intravascular access for various medical devices. This includes, but is not limited to, all arterial and vasculature access, abdominal and thoracic, cerebrospinal, genitourinary and gynecological, upper gastrointestinal and colorectal surgeries.

[0003] Embodiments generally provide improvements in introducer sheaths that resist axial compression of the sheath during insertion without limiting radial expansion and / or flexibility of the sheath. Background Art

[0004] Vascular introducer sheaths are common for endovascular procedures, such as transcatheter aortic valve replacement (TAVR), angioplasty, and stenting, to facilitate access to the vascular system for introduction of removable devices (such as guidewires, balloons, pressure transducers) and for introduction and placement of implantable devices (such as mechanical aortic valves and stents).

[0005] The vascular guide sheath is typically composed of a single or double layer hollow radial cuff or sleeve, through which the device can be passed once the guide sheath is inserted, manipulated and placed in the patient's vascular system. The sleeve terminates at one end in a radial collar that is positioned on the patient's skin and in an opening to the blood vessel. The collar typically contains a permeable seal to allow other medical devices to enter and be withdrawn from the blood vessel while avoiding significant patient blood loss, and may include one or more inlets to allow fluid to enter the patient's vascular system through the sleeve cavity.

[0006] Where the introducer sheath or the outermost layer of the introducer sheath is constructed of an elastomer or other non-rigid material, there is a risk of accidental compression, folding, shrinking or collapse of the sleeve during insertion due to shear forces between the insertion point and the outermost layer or between the arterial wall and the outermost layer.

[0007] For a single-layer introducer sheath, this may prevent insertion into the artery or create a blockage in the artery that prevents the passage of the medical device. For a double-layer introducer sheath, this may expose the inner layer during insertion, thereby causing additional hazards to the patient, such as arterial damage caused by exposure to sharp edges or shear forces between the arterial wall and the inner layer.

[0008] As a result, in such scenarios, the patient may experience excessive blood loss during or immediately after surgery, increased recovery time, excessive scarring and scar tissue formation at the insertion site, the need for greater pain management or prolonged pain management after surgery, or, in extreme cases, death.

[0009] Therefore, there is a need for improvements in such introducer sheaths that prevent axial compression or collapse during insertion while not unduly restricting radial expansion and / or flexibility of the introducer sheath.

[0010] It is expected that improving the introducer sheath in this manner will improve the safety of medical procedures and reduce the incidence of failure during insertion of the introducer sheath. Summary of the invention

[0011] In various aspects, embodiments of the present invention relate to a guide sheath for protecting the luminal surface of a blood vessel, the guide sheath comprising: an annular collar defining an opening extending through the collar, the annular collar having a circumferentially retractable elongated sleeve attached thereto, the elongated sleeve attached at the proximal opening of the elongated sleeve and extending longitudinally to define a luminal channel terminating at the distal opening of the elongated sleeve, the elongated sleeve comprising a circumferentially continuous elastomeric outer tube having two or more layers including an elastomeric layer extending longitudinally and spanning the entire length of the sleeve and a circumferentially discontinuous support layer, wherein the circumferentially discontinuous support layer is formed by one or more support elements extending longitudinally from the distal opening toward the proximal opening, and wherein the elastomeric outer tube has a smooth inner surface and a substantially round or circular cross-section.

[0012] This design ensures that the inner layer disposed in the cavity channel can move smoothly and easily within the outer tube without being hindered by friction or other forces, so that the inner layer can slide against the inner surface to provide ease of expansion and retraction. In particular, the smooth and rounded nature of the inner surface provides a number of benefits. First, it helps to more evenly distribute any forces acting on the element, thereby reducing the risk of localized wear or damage. Second, it maximizes the amount of surface area in contact between the inner layer and the tube, which in turn reduces friction and wear. Finally, it allows for more consistent and predictable movement of the inner layer within the tube.

[0013] The term "round" is understood herein to mean a shape consisting of a curve that completely encloses space. The term "substantially round" is understood herein to mean a shape that is very close to a perfect circle. Typically, a substantially round shape will have a uniform diameter from beginning to end and will not exhibit significant bulges, recesses or irregularities. The term may also encompass slightly elliptical or oval shapes, provided that they maintain a high degree of symmetry and overall circularity. For example, a shape is considered to be substantially round if the deviation from a perfect circle does not exceed a certain predetermined tolerance level. For example, the deviation from the mean diameter may always be less than 10%, 5%, 2% or 1% of the mean thickness of the outer elastomeric tube, or less than 0.05 mm, 0.02 mm or 0.01 mm.

[0014] In a preferred embodiment, the one or more support elements comprise a substantially crescent-shaped profile to provide increased section modulus without increasing thickness, and are fabricated from a polymer material known in the art.

[0015] In an alternative embodiment, the one or more support elements include a guide wire or strip composed of any of stainless steel, nitinol, or another material known in the art for providing tensile stiffness. The preferred circumferentially discontinuous support layer can be formed by a combination of a support element, such as a wire or strip selected from those materials that provide tensile stiffness, and a crescent-shaped polymer material.

[0016] In an alternative embodiment, the one or more support elements are corrugated at their outer surface to create substantially rigid ridge portions and resilient groove portions therebetween. This configuration allows each support member to flex so that the radius of the one or more support elements can dynamically change with the radius of the elastomeric layer.

[0017] The term "layer" is understood herein as a sheet or similar form of construction that can partially or completely cover another article or object. The term "layer" should not be overly limited in its construction so as to imply the presence of one or more other layers, articles or objects. For example, an article may include two or more layers that may be joined at their edges rather than in a laminated or layered manner and still be considered as two separate layers in their own right.

[0018] The term "proximal" is understood herein to define a location close to or at the attachment point, while the term "proximal" is understood to be a location distal to or at the opposite end of the attachment point. In the context of the elongated sleeve of the introducer sheath, the attachment point is the annular collar.

[0019] In an embodiment, the circumferentially discontinuous support layer can be bonded to the elastomer layer and / or bonded around the distal opening. The term "bonding" should be understood herein as defining a kind of arrangement, wherein two or more discrete objects are linked, connected, or linked so that they share a common operation, act as a single object, or present a common characteristic. This can be by embedding, adhesion, welding, suturing, compression, friction, electromagnetic or some other mechanisms known to those skilled in the art. For the purpose of illustration, the width of the term "bonding" as used herein includes but is not limited to the combination realized by interference fit, friction fit or by other mechanical locking features (e.g., utilizing a process that temporarily increases the size of the elastomer). The term "circumferential retraction" should be understood herein as defining the ability of an object to retract its circumference from an expanded size to its initial circumference or the circumference therebetween.

[0020] In a preferred embodiment, the inner surface of the elastomeric outer tube is formed partly by the elastomeric layer and partly by the support layer.

[0021] The elongate sleeve preferably includes a coiled expandable inner sheet positioned longitudinally within an inner lumen formed by a circumferentially continuous elastomeric outer tube and positioned in substantial contact with a luminal surface of the circumferentially continuous elastomeric outer tube.

[0022] The one or more support elements preferably extend longitudinally, span the entire length of the sleeve, and are bonded to the luminal surface of the continuous elastomeric layer, whereby the circumferentially discontinuous support layer is configured to resist longitudinal compression of the circumferentially continuous elastomeric outer tube along the entire length of the sleeve.

[0023] Preferably, the one or more support elements are formed of a semi-rigid material. The term "semi-rigid" is understood herein to define a material or structure that is flexible to some extent but has a degree of stiffness or rigidity, as opposed to being completely flexible or completely rigid. Preferably, the one or more support elements are more rigid than the elastomeric element. More preferably, the one or more support elements are formed of polyurethane.

[0024] Preferably, the one or more support elements are formed of a biocompatible material and have a k substantially equal to or greater than 0.1, wherein k is represented by the following formula: k = F / δ / l, where: k = longitudinal stiffness, in Newtons / millimeter / meter (N / mm / m) F = applied longitudinal force in Newtons (N) δ = extension, deflection, in millimeters (mm) l = length of the support element in meters (m).

[0025] Preferably, the one or more support elements have a k substantially equal to or greater than 2 N / mm / m. More preferably, the one or more support elements have a k substantially equal to or greater than 4 N / mm / m.

[0026] The term "stiffness" according to the above formula describes the ratio between the force applied to the body and the resulting deflection in the direction of that force. This deflection may be due to elastic or inelastic elongation or compression of the material forming the body, or to shrinkage or distortion of the body's geometry.

[0027] Preferably, the one or more support elements comprise a biocompatible material selected from the group consisting of polyurethanes, polyolefins, polypropylene, polyethylene, styrene polymers, polyesters, polycarbonates, fluorinated polymers, polyamides, polyether block amides, polyoxymethylenes, polyimides, polyetherimides, polyetheretherketones, titanium and titanium alloys, stainless steel, including alloys and blends. It may also be made of fiber or woven materials, including cotton, carbon, aramid, polyamide and polyester.

[0028] Preferably, the circumferentially continuous elastomeric outer tube is formed of a biocompatible material and has a kr substantially equal to or greater than 1.5, wherein kr is represented by the following formula: kr=ki / k0=(F*δ0) / (F*δi), where: kr = stiffness ratio of the improved elastomer layer to the original layer k0 = longitudinal stiffness of the original elastomer layer (N / mm / m) ki = longitudinal stiffness of the modified elastomer layer (N / m / m / m) F = Applied longitudinal force (N) δ0 = extension of the original elastomer layer, deflection (mm) δi = extension, deflection of the modified elastomeric layer (mm, in).

[0029] Preferably, the circumferentially continuous elastomeric outer tube has a kr substantially equal to or greater than 2.5. More preferably, the circumferentially continuous elastomeric outer tube has a kr substantially equal to or greater than 3.5.

[0030] Longitudinal stiffness is understood here to define the ratio between the force applied to the length of the body and the resulting deflection along that length.

[0031] An actual comparison of the shear stiffness of the support element with that of the elastomeric layer requires applying equal shear forces to each (where the shear forces are comparable to those encountered during insertion of the introducer sheath into the incision) and measuring the deflection of each to obtain a ratio, as described in the above formula.

[0032] Preferably, the circumferentially continuous elastomeric outer tube comprises a biocompatible material selected from the group consisting of silicone, isoprene, latex and latex substitute rubbers, and other thermoplastic elastomers.

[0033] Preferably, the one or more supporting elements comprise a material selected from the group consisting of a fibrous material, a textile, a metal, a metal alloy, a polymer, a mixture thereof or a composite material, the selected material having a modulus of at least 50 times that of the continuous elastomeric layer, for example as measured according to ASTM D638 or ASTM D412 or ASTM D792.

[0034] More preferably, the one or more support elements comprise a material having a modulus of at least 200 times that of the continuous elastomeric layer. Still more preferably, the one or more support elements comprise a material having a modulus of about 300 times that of the continuous elastomeric layer.

[0035] In a further aspect, embodiments of the present invention are directed to a system for protecting a luminal surface of a blood vessel, the system comprising an introducer sheath formed of an annular collar defining an opening extending therethrough, the annular collar having a circumferentially retractable elongated sleeve attached thereto, the elongated sleeve attached at a proximal opening of the elongated sleeve and extending longitudinally to define a luminal passage terminating at a distal opening of the elongated sleeve, the elongated sleeve comprising a circumferentially continuous elastomeric outer tube having two or more layers, the two or more layers The elongated sleeve comprises a continuous elastomeric layer extending longitudinally and spanning the entire length of the sleeve and a circumferentially discontinuous support layer, the elongated sleeve comprising a rolled expandable inner sheet, the expandable inner sheet being longitudinally positioned within an inner cavity formed by the circumferentially continuous elastomeric outer tube and being positioned to substantially contact the luminal surface of the circumferentially continuous elastomeric outer tube, wherein the circumferentially discontinuous support layer is formed by one or more support elements extending longitudinally from the distal opening toward the proximal opening, and wherein the elastomeric outer tube has a smooth inner surface and a substantially circular cross-section.

[0036] The preferred system further comprises a dilator having a dilator tip having a larger diameter than the distal opening of the elongate sleeve, wherein the dilator tip is configured to pass through the lumen formed by the expandable inner sheet along the length of the circumferentially retractable elongate sleeve.

[0037] The one or more support elements preferably extend longitudinally, from the distal opening or near the distal opening to the proximal opening or as close to the proximal opening as possible, across the entire length of the sleeve, and are bonded to the luminal surface of the continuous elastomeric layer, whereby the circumferentially discontinuous support layer is configured to resist longitudinal compression of the circumferentially continuous elastomeric outer tube along the entire length of the sleeve.

[0038] In alternative embodiments, the one or more support elements may extend partially along the length of the sleeve and may be circumferentially discontinuous along its length. Alternatives to "bonding" may include adhesives, stitching, material reflow, coextrusion, encapsulation (or lamination), or other such methods known in the art for increasing friction therebetween.

[0039] The one or more support elements are preferably formed of a biocompatible material and have a k substantially equal to or greater than 1, wherein k is represented by the formula: k = F / δ / l, where: k = longitudinal stiffness, in Newtons / millimeter / meter (N / mm / m) F = applied longitudinal force in Newtons (N) δ = extension, deflection, in millimeters (mm) l = length of the support element in meters (m).

[0040] The circumferentially continuous elastomeric outer tube is alternatively formed of a biocompatible material and has a kr substantially equal to or greater than 1.5, wherein kr is represented by the formula: kr=ki / k0=(F*δ0) / (F*δi), where: kr = stiffness ratio of the improved elastomer layer to the original layer k0 = longitudinal stiffness of the original elastomer layer (N / mm / m) ki = longitudinal stiffness of the modified elastomer layer (N / m / m / m) F = Applied longitudinal force (N) δ0 = extension of the original elastomer layer, deflection (mm) δi = extension, deflection of the modified elastomeric layer (mm, in).

[0041] The one or more supporting elements preferably comprise a material selected from the group consisting of: a fibrous material, a textile, a metal, a metal alloy, a polymer, a mixture thereof or a composite material, the selected material having a modulus of at least 50 times that of the continuous elastomeric layer.

[0042] The support element should have a higher tensile modulus and flexural modulus than the elastomeric material to provide the desired structural improvement. As the modulus difference increases, the required size of the support element decreases, which means that the influence of the support on the radial expansion stiffness is reduced. For example, for the same longitudinal stiffness effect, the cross-section of the support element made of titanium can be much smaller than that of the polyurethane support element. The support element also needs to have a certain flexibility to allow the device to bend through the patient's anatomical structure. Also consider the anti-buckling property-a small stainless steel wire will have very good tensile elongation, but the size will need to be determined to maintain sufficient compression resistance. From this point of view, the modulus of the support element material can be 10,000 times the modulus of the elastomer (for example, 40A TPE at 0.2MPa to stainless steel at 210GPa).

[0043] In a further aspect, an embodiment of the invention is directed to a method comprising the steps of obtaining an introducer sheath formed of an annular collar defining an opening extending through the collar, the annular collar having a circumferentially retractable elongated sleeve attached thereto, the elongated sleeve attached at a proximal opening of the elongated sleeve and extending longitudinally to define a lumen passageway terminating at a distal opening of the elongated sleeve, the elongated sleeve comprising a circumferentially continuous elastomeric outer tube having two or more layers, the two or more layers comprising a plurality of elastomeric outer tubes extending longitudinally and extending across the sleeve. A continuous elastomeric layer extending along the entire length of the tube, and a circumferentially discontinuous support layer bonded to the continuous elastomeric layer and formed by one or more support elements, the support layer being bonded around the distal opening and extending longitudinally from the distal opening toward the proximal opening; obtaining an expandable inner sheet; longitudinally positioning the expandable inner sheet within an inner cavity formed by the circumferentially continuous elastomeric outer tube, and positioning it to be substantially in contact with the luminal surface of the circumferentially continuous elastomeric outer tube, whereby the circumferentially discontinuous support layer is configured to resist longitudinal compression of the circumferentially continuous elastomeric outer tube.

[0044] The preferred method may further include the steps of obtaining a dilator having a dilator tip having a larger diameter than the distal opening of the elongated sleeve; and passing the dilator tip through the lumen formed by the expandable inner sheet along the length of the circumferentially retractable elongated sleeve.

[0045] The preferred method may further comprise the step of passing the dilator tip and introducer sheath through the vessel wall.

[0046] Embodiments are designed to provide an introducer sheath that can be inserted into a blood vessel without crimping, folding, or compressing opposite the direction of insertion, while still allowing radial expansion and / or tangential flexing.

[0047] The functionality of the embodiments depends on a novel design in which the support element or spine is incorporated into a circumferentially continuous elastomeric outer tube of a retractable elongated sleeve and extends longitudinally. The continuous elastomeric layer is the outermost layer of the elongated sleeve through which the introducer or dilator passes and preferably retains the ability to bend during insertion.

[0048] Collapse, folding or compression of the elongated sleeve may result in insertion failure, and therefore incorporating axially blocking support elements into the circumferentially discontinuous support layer will result in improved functionality of the improved introducer sheath.

[0049] The introducer sheath preferably provides a balance of properties, including sufficient bendability to navigate through a network of vascular channels, sufficient rigidity to prevent kinking and buckling, and sufficient elasticity to retract when circumferentially expanded or when inadvertently bent or kinked.

[0050] According to an embodiment, the design concept is provided by a combination of a continuous elastomeric layer and a circumferentially discontinuous support layer, which imparts complementary physical properties that cannot be provided by any single component. Specifically, the circumferentially discontinuous support layer of the embodiment provides rigidity, while the circumferentially continuous elastomeric outer layer provides elasticity, and each provides a sufficient degree of bendability to navigate through the patient's vascular system.

[0051] In a preferred embodiment of the invention, the one or more support elements are substantially linear in the longitudinal direction.

[0052] Longitudinal is understood herein to define a direction through a lumen passage defined by a proximal opening and a distal opening, from a proximal opening to a distal opening, or from a distal opening to a proximal opening.

[0053] The term "radial direction" is understood herein to define a direction that is substantially perpendicular to the axial direction.

[0054] The term "substantially linear" is understood herein to define a configuration that is largely linear but may contain some non-linear elements that do not affect the overall directionality and shape on a macroscopic scale.

[0055] The term "substantially in contact" is understood herein to define an assembly where a significant portion of one surface is in contact with another surface, however, contact is not required with the entirety of each surface.

[0056] In a preferred embodiment, the expandable inner sheet is an expandable inner layer formed by a single sheet rolled upon itself and is characterized by an outward annular resistance.

[0057] The expandable inner sheet may include cuts, slits and other sections to improve or modify the physical properties of the elongated sleeve, particularly the bendability, kink resistance or elasticity of the elongated sleeve.

[0058] The expandable inner sheet may be integrally formed of a substantially uniform rigid polymer material including notches or cutouts.The expandable inner sheet may be configured to be rolled into an overlapping arrangement in its relaxed state and helically wound around the longitudinal axis of the circumferentially retractable elongate sleeve.

[0059] In some embodiments, the support element may extend partially from the distal end of the circumferentially retractable elongated sleeve to the proximal end of the circumferentially retractable elongated sleeve. It may extend intermittently or continuously therebetween.

[0060] In various embodiments, the profile of the circumferentially continuous elastomeric outer tube along the length of the circumferentially retractable elongate sleeve may have a constant radius or a dynamic radius, whereby the sleeve is formed to be tapered or a tapered portion in the axial direction.

[0061] In a preferred configuration and embodiment, the support element is a substantially straight extrusion that extends longitudinally from the distal end of the circumferentially retractable elongate sleeve to the proximal end of the circumferentially retractable elongate sleeve.

[0062] The support element may be made of the same or similar material as the circumferentially continuous elastomeric outer tube, having varying solidity or density, the support element may be made of the same material as the expandable inner layer, or the support element may be made of a metal substrate or other material.

[0063] In alternative embodiments, a circumferentially continuous elastomeric outer tube may be optimized for accommodation of a support element or for smooth insertion of an introducer sheath into a patient.

[0064] In a preferred embodiment, the support element may be bonded to the inner surface of the circumferentially continuous elastomeric outer tube and extend longitudinally along the length of the circumferentially retractable elongated sleeve from the distal end of the circumferentially retractable elongated sleeve to the proximal end of the circumferentially retractable elongated sleeve. It may extend intermittently or continuously therebetween.

[0065] In a preferred embodiment, the expandable inner sheet is a spirally wound sheet of rigid polymeric material configured to be wound in its relaxed state into an overlapping arrangement and helically wound about the longitudinal axis of the circumferentially retractable elongate sleeve.

[0066] In alternative embodiments and configurations, the addition of an expandable inner sheet may be applied to any of these alternative embodiments and configurations of a circumferentially continuous elastomeric outer tube.

[0067] In a preferred embodiment, the expandable inner sheet expands as the dilator or surgical instrument is inserted into the lumen of the circumferentially retractable elongated sleeve. The expansion of the expandable inner sheet causes the subsequent expansion of the circumferentially continuous elastomeric outer tube at the portion not reinforced by the circumferentially discontinuous support layer.

[0068] In a further aspect, an embodiment relates to a method of using an introducer sheath, the method comprising the steps of obtaining an introducer sheath according to any one of the embodiments defined herein; passing a rigid introducer or dilator through the lumen of the introducer sheath; and introducing the introducer sheath into a blood vessel.

[0069] In a further aspect, an embodiment relates to a method of manufacturing an introducer sheath, the method comprising the steps of obtaining a rigid collar and a continuous elastomeric layer according to a preferred embodiment of the present invention; and attaching the continuous elastomeric layer to the rigid collar at a proximal opening.

[0070] In another aspect, an embodiment relates to a manufacturing method, which may include the following additional steps: obtaining a second sleeve layer according to a preferred embodiment of the present invention; attaching the second sleeve layer to the rigid collar at the proximal opening; and placing the second sleeve layer within the continuous elastomeric layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figures 1(a) and 1(b) provide front perspective views of prior art guide sheaths, wherein 1(a) provides a front perspective view of a double-layer composite guide sheath, and 1(b) provides a front perspective view of a single-layer sheath.

[0072] Figure 2(a) to Figure 2(c) Side cross-sectional views of three stages of the prior art problem are provided, wherein 2(a) shows an introducer sheath known in the art prior to insertion, 2(b) shows the introducer sheath and skin-body interface during insertion, and 2(c) shows the final wrinkling that occurs on the skin surface after insertion.

[0073] Figure 3 A front perspective view of an introducer sheath according to an embodiment of the present invention is provided.

[0074] 4(a) and 4(b) provide detailed front perspective views of embodiments according to the present invention, wherein 4(a) shows a modification of the outer layer of the illustrated embodiment, and 4(b) shows the modified outer layer, as well as the inner layer.

[0075] Figure 5 A detailed cross-sectional view of the embodiment shown in FIG. 4( a ) along line AA is provided.

[0076] Figure 6(a) to Figure 6(c) Detailed side cross-sectional views of various embodiments of the present invention are provided, wherein 6(a) shows a support element "in line" with the outer layer of the sleeve, 6(b) shows a support element "outside" the outer surface of the sleeve, and 6(c) shows a support element "laminated" within the outer layer of the sleeve.

[0077] Figure 7(a) to Figure 7(c) Side cross-sectional views of three stages during use of a sleeve according to an embodiment of the present invention are provided, wherein 7(a) shows an introducer sheath before insertion, 7(b) shows the improved introducer sheath and skin-body interface during insertion, and 7(c) shows the outer layer of the improved introducer sheath smoothly passing through the skin after insertion.

[0078] Figure 8 A front perspective view of an alternative embodiment of the present invention having multiple support elements is provided.

[0079] Several embodiments of the invention are described in the following examples. DETAILED DESCRIPTION

[0080] Referring to FIG. 1 , known guide sheaths in the prior art take one of two general forms. FIG. 1( a) illustrates a double-layer guide sheath 100 known in the art. Such a double-layer guide sheath is composed of three main components, namely, a collar 110, an outer layer 120, and an inner layer 130. The double-layer guide sheath shown in FIG. 1( a) is composed of a coiled inner layer 130 that allows the guide sheath 100 to expand and retract radially and is loosely coiled within an elastomeric outer layer 120 so that each layer can slide against another layer to provide ease of movement within a blood vessel. One or both of the outer layer 120 or the inner layer 130 can be bonded to the collar 110. The collar 110 provides an opening for introducing a dilator into the lumen of the inner layer 130.

[0081] FIG. 1( b) illustrates an alternative single-layer introducer sheath 150 known in the art, which is generally constructed of two main components; a rigid annular collar 160 and an elongated sleeve 170. The collar 160 is a hollow structure bonded to the elongated sleeve 170. The collar 160 allows material to be introduced into the lumen 180 of the sleeve 170 through the opening of the sleeve. The annular collar 160 is formed of a rigid material to allow a user to manipulate the collar and pass an object or material through it into the lumen 180. It terminates in an opening of similar diameter to the opening of the sleeve 170 so that the sleeve 170 can be placed and secured therein, thereby joining the two components.

[0082] Both forms of prior art introducer sheaths are formed by an elongated flexible tube attached to a collar. During the insertion of the introducer sheath into a blood vessel, the form of the introducer sheaths 100 and 150 is maintained by a dilator which is placed within the introducer sheath prior to use and through which the medical device is introduced.

[0083] Since the outer surface of the introducer sheath must be smooth and flexible to avoid snagging or tearing delicate blood vessels, in both cases, the outer layer 120 and sleeve 170 may be formed of materials that tend to fold or collapse during insertion; thereby creating the possibility of failed insertion.

[0084] Figure 2(a) to Figure 2(c) The problems caused by the prior art devices are shown in more detail. Although FIG. 2 shows the problem of the prior art device in a two-layer form, this problem exists for all introducer sheaths formed of a smooth and flexible outer layer material. FIG. 2( a) shows the prior art introducer sheath of FIG. 1( a) prior to insertion. Prior to being introduced into a blood vessel, the dilator 200 is inserted through the collar 110 (not shown) so that the dilator tip 210 extends through the distal opening 220 and is optimally positioned against the inner layer 230 and the outer layer 240. An opening or incision 250 is formed in the skin 260 of the patient 270 to provide access for the introducer sheath 100 and dilator 200 through the arterial wall 280 and into the artery 290.

[0085] FIG. 2( b) illustrates the prior art introducer sheath of FIG. 1( a) during insertion and when engaged with the incision 250 and the skin 260. The dilator tip 210 is inserted into the incision 250, thereby expanding the opening enough to allow the introducer sheath 100 to enter the interior 290 of the artery. During the insertion process, the outer layer 240 contacts the skin 260 and the inner surface of the incision 250. The friction against the outer layer 240 and the elasticity of the material forming the outer layer 240 cause the outer layer 240 to shrink, compress and fold in a direction from the distal opening 220 toward the proximal end (not shown). This shrinkage 292 exposes the inner layer 230. The sharp edges formed at the distal opening often catch on the incision 250 or the arterial wall 280 during the insertion process and cause damage thereto.

[0086] FIG. 2( c) shows the prior art introducer sheath of FIG. 1( a) during insertion into an artery 290. Once collapse of the outer layer 240 occurs, the inner layer 230 is exposed. The dilator tip 210 continues to enter the interior 290 of the artery, and the introducer sheath 100 follows. The collapsed outer layers 292, 240 cause damage to the arterial wall 280 due to the sharp edge of the inner layer 230 at the distal opening 220, or due to the collapse of the outer layers 292, 240. Cause damage to the arterial wall 280. This failed insertion requires another attempt at introducer sheath insertion using a new introducer sheath, which in turn introduces further risk to the patient.

[0087] Figure 2(a) to Figure 2(c) The problems shown also apply to single-layer introducer sheaths of the type shown in Figure 1(b). Although no sharp inner layer is exposed, any collapse or folding of the single-layer sleeve may lead to suboptimal insertion, blockage, and subsequent insertion failure.

[0088] Figure 3 An improved guide sheath according to an embodiment of the present invention is shown. The guide sheath 300 is generally composed of two main components: a rigid annular collar 310 is coupled to an elongated sleeve 320 at the sleeve proximal end 330. The collar 310 is a hollow rigid structure and is configured to allow a user to feed material through the collar, through an opening at the sleeve proximal end 330 into the lumen of the sleeve 320. The collar 310 may include an inlet (not shown) to allow fluid to enter the lumen of the guide sheath 300, and is formed of a rigid material to allow a user to manipulate the collar and pass an object or material therethrough via an opening 312 formed at the proximal end 332 of the collar 310. The collar 310 terminates at a distal end 334 in a narrowed opening having a diameter similar to the opening of the sleeve 320 at the sleeve ring proximal end 330. The similarity in diameter of the distal end 334 of the collar 310 and the proximal end 330 of the sleeve enables the sleeve 320 to be placed and secured within the collar 310, thereby joining the two components together.

[0089] The sleeve 320 extends away from the proximal end 330 of the collar 310 at a critical point along the length of the sleeve 320 to facilitate insertion into an incision formed to access the patient's vascular system. The sleeve 320 is a smooth, flexible structure that tapers in part between the proximal end 330 and the distal end 340 to ease insertion and navigation of the sheath within the vessel. The sleeve 320 is expandable and retractable to enable a wider dilator, valve, or other medical device to be introduced into the patient's body through the lumen of the sleeve 320; the sleeve can expand around the device and can gently press against the luminal wall of the vessel as it is advanced through the vessel; and then once the device is removed, also retract to a size similar to its original size so that it can be gently removed from the patient.

[0090] The sleeve 320 is formed of two thin flexible layers: an elastomeric outer tube 350 and an expandable inner layer 360. The elastomeric outer tube 350 is formed as an elongated tube within which is maintained a coiled expandable inner sheet material forming the expandable inner layer 360. The elastomeric outer tube 350 is improved upon the prior art by the addition of a semi-rigid support layer in the form of a widened semi-rigid support element 370.

[0091] The elastomeric outer tube 350 is formed of an elastomeric material that can be stretched when pressure is applied from within the lumen of the sleeve 320, and the sleeve 320 also substantially returns to its original diameter once the internal pressure is relaxed. In a relaxed state, the elastomeric outer tube 350 has a wall thickness of less than 0.4 mm, preferably less than 0.2 mm.

[0092] With reference to Fig. 4 (a) and Fig. 4 (b), the elastomeric outer tube 350 is formed of multiple layers including an elastomeric layer 410 and a semi-rigid support layer 420. The elastomeric layer 410 is formed of silicone to maximize elasticity and minimize wall thickness, thereby minimizing the risk of damaging the vascular system. However, those skilled in the art may select other materials for this purpose by evaluating potential materials and selecting those materials with suitable properties. Suitable materials may include materials such as latex rubber or non-latex substitutes (including nitrile rubber, polyvinyl chloride, chloroprene rubber, polypropylene and polyisoprene, polyurethane, other thermoplastic elastomers, etc.).

[0093] The elastomeric layer 410 is formed by an extrusion process and is shaped by the process to receive the semi-rigid support element 370 within a groove formed longitudinally within the luminal surface 430 of the elastomeric layer 410. The elastomeric layer 410 and the semi-rigid support member 370 are formed into complementary shapes and bonded together by co-extrusion so that the resulting elastomeric outer tube 350 is formed of the assembled and bonded elastomeric layer 410 and the semi-rigid support element 370.

[0094] The semi-rigid support element 370 is constructed of a polymeric material. It is formed into a substantially crescent or D-shape and is contained within a complementary shape formed by the elastomeric layer 410. The shape and semi-rigid support member extend longitudinally from the distal end 340 toward the collar 310. In a preferred embodiment, the semi-rigid support element 370 extends completely from the distal end 340 to the collar 310 without interruption.

[0095] The elastomeric outer tube 350 maintains the expanded inner layer 360 in a coiled form within the lumen of the elastomeric outer tube 350, which contacts and applies an outward force to the luminal surface 430 of the elastomeric layer 410. Once coiled and positioned within the luminal surface 430 of the elastomeric layer 410, the elastomeric outer tube 350 and the inner layer 360 form a sleeve lumen 440 to create a composite sheath.

[0096] Figure 5 A cross section of the elastic outer tube 350 along the line AA shown in FIG. 4( a ) is provided. Figure 5 , the semi-rigid support element 370 has a thickness between 0.1 mm and 0.5 mm and is shaped by coextrusion to fill a position co-linear with the generally circular contour of the elastomeric outer tube 350; this allows the luminal surface 430 of the elastomeric layer 410 to be uninterrupted and complete. In this form, the contour of the elastomeric outer tube 350 protrudes outwardly, while the contour of the semi-rigid support element 370 protrudes longitudinally. In this form, the outermost surface of the semi-rigid support element 370 is surrounded by the elastomeric layer 410 with a thinner or similar thickness than the rest of the elastomeric layer 410.

[0097] FIG. 4( a ) shows a preferred configuration and embodiment, which will be Figure 5 4( a) and 4( b), the outermost surface of the elastomeric outer tube 350 transitions from a smooth cylindrical shape to a smooth tapered, rounded, or chamfered shape so that the protrusions in the outer surface of the elastomeric outer tube 350 do not interfere with the incision or artery during insertion.

[0098] The outermost surface of the elastomeric outer tube 350 has a uniform thickness such that it extends over the semi-rigid support element 370 , thereby exposing the outline of the semi-rigid support element on the outermost surface of the elastomeric outer tube 350 .

[0099] A range of alternative shapes and configurations may be selected by the skilled person depending on the desired properties of the elastomeric material or semi-rigid support element or the ease of manufacture. Particularly useful configurations are shown in Figures 6(a), 6(b) and 6(c).

[0100] FIG6( a) shows another configuration of the elastomeric layer 410 and the semi-rigid support element 370, wherein the semi-rigid support element 370 remains substantially crescent-shaped and its inner radius corresponds to the inner radius of the elastomeric layer 410, so that the combination of the two components produces a substantially circular profile, however, the elastomeric layer 410 is Figure 5 This alternative construction is formed by bonding or attaching each side edge of the semi-rigid support element 370 that contacts the elastomeric layer 410 to the elastomeric layer 410 to form a circumferentially continuous elastomeric outer tube 350. In this configuration, the layers are not laminated or bonded on their upper or lower surfaces.

[0101] 6( b) illustrates an alternative embodiment of the elastomeric layer 410 and the semi-rigid support element 370, wherein the semi-rigid support element 370 is also substantially crescent-shaped, but its inner radius matches the outer radius of the elastomeric layer 410 and is attached to the outer surface of the elastomeric layer. Thus, this embodiment requires that the inner surface of the semi-rigid support element 370 be in contact with the elastomeric layer 410 to be attached thereto or formed therewith to create the elastomeric outer tube 350.

[0102] FIG6( c ) illustrates an alternative configuration of an elastomeric layer 410 and a semi-rigid support element 370, wherein the semi-rigid support element 370 remains substantially crescent-shaped, however, it is laminated between two elastomeric layers 410. The elastomeric outer tube 350 has a substantially circular outer profile that is modified such that a portion of the profile has a protrusion with a larger radius than the remainder of the profile. The elastomeric outer tube 350 has a smooth, substantially circular, continuous inner profile. The semi-rigid support element 370 is contained between the outermost elastomeric layer 410 and the innermost elastomeric layer 410, and is contained within the protrusion in the outer surface of the elastomeric outer tube 350.

[0103] Encapsulating or laminating the semi-rigid support element 370 within the material of the elastomeric outer tube 350 allows the two components to be assembled without the need for bonding or attachment. This form of construction is particularly advantageous in situations where bonding of the semi-rigid support element 370 or the elastomeric layer 410 may not be possible; because the semi-rigid support element can be held in the desired position by lamination or pressure rather than bonding. Such situations may occur where the material is chemically incompatible with the bonding agent (e.g., in the case of a semi-rigid support element using metal) or where bonding increases manufacturing costs or difficulties.

[0104] FIG. 7( a), FIG. 7( b) and FIG. 7( c) illustrate the prior art problems solved by the embodiments described herein. FIG. 7( a) illustrates the improved guide sheath described herein prior to insertion. Dilator 200 is inserted through collar 310, and dilator tip 210 extends through distal opening 220 and is positioned against inner layer 230 and outer layer 240, whereby it is supported in place by semi-rigid support element 370. An opening or incision 250 is formed in skin 260 of patient 270 to provide access for guide sheath 300 and dilator 200 through arterial wall 280 into artery 290.

[0105] FIG. 7( b) illustrates the improved guide sheath of FIG. 4( b) during insertion and when engaging the incision 250 and the skin 260. The dilator tip 210 is inserted into the incision 250, thereby expanding the opening enough to allow the guide sheath 100 to enter the interior 290 of the artery. During the insertion process, the outer layer 240 contacts the skin 260 and the inner surface of the incision 250. The semi-rigid support element 370 stabilizes the position of the outer layer 240 in the longitudinal direction, wherein the friction of the outer layer 240 caused during the passage of the dilator 200 through the opening or incision 250 is prevented by the semi-rigid support element 370, thereby minimizing the shrinkage, compression or folding of the outer layer 240 in the direction from the distal opening 220 toward the proximal end (not shown). This prevents the inner layer 230 and the sharp edges typically formed at the distal opening from being exposed, which can catch and damage the incision 250 or the arterial wall 280 during the insertion process.

[0106] FIG7( c ) shows the improved introducer sheath of FIG4( b ) during deeper insertion into artery 290. Inner layer 230 is minimally exposed in artery 290, and its sharp edges are protected by outer layer 220. However, even in the event of removal and reinsertion, the likelihood of insertion failure is reduced, as is the likelihood of damaging the vessel.

[0107] Figure 7(a) to Figure 7(c) The problems shown also apply to the single layer introducer sheath illustrated in Figure 4(a). Although there is no possibility of exposing the inner layer, collapse or folding of the single layer may lead to suboptimal insertion, blockage and subsequent failure conditions, and thus the semi-rigid support element 370 similarly reduces the risk.

[0108] Figure 8 An alternative construction of an improved introducer sheath is shown in which an elastomeric outer tube 850 having a lumen 840 therethrough is constructed of an elastomeric layer 810 and three semi-rigid support elements 870. The three semi-rigid support elements 870 are equally spaced around the substantially circular profile of the elastomeric outer tube 810 and are constructed in accordance with the semi-rigid support elements 870. The elastomeric outer tube 850 is constructed in accordance with the elastomeric outer tube 850 in all other respects. However, Figure 8 The construction of may be preferred in cases where the material selected for construction of the elastomeric layer 810 is very thin or very soft. Such materials are often preferred for insertion into small blood vessels, such as in ophthalmic microsurgery.

[0109] The elastomeric layer 810 is shaped to accommodate each semi-rigid support element 870 such that the resulting elastomeric outer tube 850 is formed by the assembled elastomeric layer 810 and semi-rigid support elements 870 that maintain the expanded inner layer therein.

[0110] Each semi-rigid support element 870 is positioned co-linearly with the inner circular contour of the elastomeric outer tube 850, such that the inner surface of the elastomeric outer tube 850 is uninterrupted and complete. The outer contour of the outer surface of the elastomeric outer tube 850 is shaped by the contour of each semi-rigid support element 870, such that the outermost surface of each semi-rigid support element 870 is covered by the elastomeric layer 810 with a thickness similar to the rest of the elastomeric outer tube 870.

[0111] For particularly sensitive insertions, the outermost surface of the elastomeric outer tube 850 has a uniform thickness such that portions of the elastomeric layer 810 are thicker between the individual semi-rigid support elements 870 and thinner where they extend onto each semi-rigid support element 870 to provide a substantially smooth, rounded, and uniform outermost and innermost surface of the elastomeric outer tube 870.

[0112] Throughout this specification, the word "comprise" or variations such as "comprising" or "including" will be understood to imply the inclusion of stated elements, integers or steps, or groups of elements, integers or steps, but not the exclusion of any other elements, integers or steps, or groups of elements, integers or steps.

[0113] It should be understood that the terms "fastener" or "fastening", "coupling" or "sealing" can be used interchangeably when used alone or with other terms (such as "device" or others), where a person skilled in the art considers the interpretation of the term to be functionally interchangeable with the other term. Further, the use of one of the above terms does not exclude the interpretation when the other term is included.

[0114] As described herein, various devices and components of the devices can be provided in various sizes and / or dimensions as required. Suitable sizes and / or dimensions will vary according to the specifications or use locations of the connecting components, which can be selected by those skilled in the art.

[0115] It will be appreciated that features, elements and / or characteristics described with respect to one embodiment of the disclosure may be used with other embodiments of the invention, as desired.

[0116] Although the preferred embodiments of the present disclosure have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the disclosure and the accompanying claims.

[0117] It should be understood that when an element or layer is referred to as being “on” or “in” another element or layer, the element or layer can be directly on or within the other element or layer or on or within intervening elements or layers. In contrast, when an element is referred to as being “directly on” or “directly within” another element or layer, there are no intervening elements or layers present.

[0118] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0119] It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or sections in this article, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish an element, component, region, layer or section from another region, layer or section. Therefore, without departing from the teaching content of the present disclosure, the first element, component, region, layer or section can be referred to as the second element, component, region, layer or section.

[0120] Spatially relative terms, such as "lower", "upper", "top", "bottom", "left", "right", etc., may be used herein for convenience of description to describe the relationship of one element or feature to another one or more elements or features as shown in the accompanying drawings. It should be understood that in addition to the orientations depicted in the accompanying drawings, spatially relative terms are also intended to cover different orientations of the structure in use or operation. For example, if the device in the accompanying drawings is turned over, the element described as "lower" relative to other elements or features will be oriented "up" relative to the other elements or features. Therefore, the exemplary term "lower" can include both upper and lower orientations. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0121] The terms used in this article are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "a", "an", and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It will be further understood that the terms "comprise", "include", and / or "comprising" when used in this specification indicate the presence of stated features, integers, steps, operations, elements, and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, and / or groups thereof.

[0122] Embodiments of the present specification are described herein with reference to, for example, figures and / or cross-sectional views that schematically illustrate preferred embodiments (and intermediate structures) of the present specification. As such, variations in the illustrated shapes due to, for example, manufacturing techniques and / or tolerances are contemplated. Thus, the embodiments of the present specification should not be construed as limited to the specific shapes of the components illustrated herein, but rather include deviations in shapes due to, for example, manufacturing.

[0123] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this specification belongs. It will be further understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such herein.

[0124] Any reference in this specification to "one embodiment," "an embodiment," "an example embodiment," etc. means that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of this specification. The appearances of such phrases in various places in this specification do not necessarily all refer to the same embodiment. Further, when a particular feature, structure, or characteristic is described in conjunction with any embodiment, it is also within the knowledge of those skilled in the art to implement and / or use such feature, structure, or characteristic in conjunction with other embodiments.

[0125] The embodiments are also intended to include or otherwise cover methods of use and methods of manufacture of any or all of the elements disclosed above.

[0126] Although the present invention has been described above in the sense of specific embodiments, it should be understood that the present invention is not limited to the disclosed embodiments. When reading the teaching content of the present disclosure, many modifications and other embodiments of the present invention will occur to those skilled in the art to which the present invention belongs, and these modifications and other embodiments are intended to be covered by the present disclosure and the appended claims.

[0127] All publications mentioned in this specification are incorporated herein by reference. Any discussion of documents, acts, devices, articles and the like which have been included in this specification is for the purpose of providing a context for the present invention only. It should not be taken as an admission that any or all of these matters form part of the prior art base or are common general knowledge in the field relevant to the present invention as it existed in Australia or elsewhere before the priority date of the claims of this application.

[0128] It is actually intended that the scope of the present invention should be determined by proper interpretation and construction of the appended claims and their legal equivalents as understood by those skilled in the art relying on the disclosure in this specification and the drawings.

Claims

1. A guide sheath for protecting the luminal surface of a blood vessel, the guide sheath comprising: an annular collar defining an opening extending through the collar, The annular collar has a circumferentially retractable elongated sleeve attached thereto, the elongated sleeve being attached at a proximal opening of the elongated sleeve and extending longitudinally to define a lumen passage terminating at a distal opening of the elongated sleeve, The elongated sleeve comprises a circumferentially continuous elastomeric outer tube having two or more layers including an elastomeric layer extending longitudinally and spanning the entire length of the sleeve and a circumferentially discontinuous support layer, wherein the circumferentially discontinuous support layer is formed by one or more support elements extending longitudinally from the distal opening toward the proximal opening, and The elastic outer tube has a smooth inner surface and a substantially circular cross-section.

2. The guide sheath according to claim 1, characterized in that: The inner surface of the elastomeric outer tube is formed by the elastomeric layer and the support layer, preferably the support layer forms less than 50%, more preferably less than 25% of the inner surface.

3. The guide sheath according to claim 1, characterized in that: The outer surface of the elastomeric outer tube is formed by the elastomeric layer.

4. The guide sheath according to claim 1, characterized in that: The elongated sleeve includes a coiled expandable inner sheet positioned longitudinally within an inner lumen formed by the circumferentially continuous elastomeric outer tube and positioned in substantial contact with a luminal surface of the circumferentially continuous elastomeric outer tube.

5. The guide sheath according to claim 1, characterized in that: The one or more support elements extend longitudinally, span the entire length of the sleeve, and are bonded to the luminal surface of the continuous elastomeric layer, whereby the circumferentially discontinuous support layer is configured to resist longitudinal compression of the circumferentially continuous elastomeric outer tube along the entire length of the sleeve.

6. The introducer sheath according to claim 1, characterized in that: The one or more support elements are formed of a biocompatible material and have a k value substantially equal to or greater than 0.1, wherein k is represented by the following formula: k = F / δ / l, where: k = longitudinal stiffness, in Newtons / millimeter / meter (N / mm / m) F = applied longitudinal force in Newtons (N) δ = extension, deflection, in millimeters (mm) l = length of the support element in meters (m).

7. The introducer sheath according to claim 1, characterized in that: The circumferentially continuous elastomeric outer tube is formed of a biocompatible material and has a kr value substantially equal to or greater than 1.5, wherein kr is represented by the following formula: kr=ki / k0=(F*δ0) / (F*δi), where: kr = stiffness ratio of the improved elastomer layer to the original layer k0 = longitudinal stiffness of the original elastomer layer (N / mm / m) ki = longitudinal stiffness of the modified elastomer layer (N / mm) F = Applied longitudinal force (N) δ0 = extension of the original elastomer layer, deflection (mm) δi = extension of the modified elastomeric layer, deflection (mm).

8. The introducer sheath according to claim 1, characterized in that: The one or more support elements comprise a material selected from the group consisting of: a fibrous material, a textile, a metal, a metal alloy, a polymer, a mixture thereof or a composite material, the selected material having a modulus of at least 50 times that of the continuous elastomeric layer.

9. The introducer sheath according to claim 1, characterized in that: The circumferentially discontinuous support layer is formed by a combination of a support element and a crescent-shaped polymer material, wherein the support element includes a guide wire or strip composed of any one of stainless steel, Nitinol, or a mixture or composite thereof.

10. A system for protecting a luminal surface of a blood vessel, the system comprising an introducer sheath formed of: an annular collar defining an opening extending through the collar, The annular collar has a circumferentially retractable elongated sleeve attached thereto, the elongated sleeve being attached at a proximal opening of the elongated sleeve and extending longitudinally to define a lumen passage terminating at a distal opening of the elongated sleeve, The elongated sleeve comprises a circumferentially continuous elastomeric outer tube having two or more layers including a continuous elastomeric layer extending longitudinally and across the entire length of the sleeve and a circumferentially discontinuous support layer, The elongated sleeve includes a coiled expandable inner sheet positioned longitudinally within an inner lumen formed by the circumferentially continuous elastomeric outer tube and positioned in substantial contact with a luminal surface of the circumferentially continuous elastomeric outer tube, in, The circumferentially discontinuous support layer is formed by one or more support elements extending longitudinally from the distal opening toward the proximal opening, and The elastic outer tube has a smooth inner surface and a substantially circular cross-section.

11. The system according to claim 10, characterized in that A dilator is included having a dilator tip having a larger diameter than a distal opening of the elongated sleeve, wherein the dilator tip is configured to pass through an inner lumen formed by the expandable inner sheet along the length of the circumferentially retractable elongated sleeve.

12. The system according to claim 10, characterized in that The one or more support elements extend longitudinally, span the entire length of the sleeve, and are bonded to the luminal surface of the continuous elastomeric layer, whereby the circumferentially discontinuous support layer is configured to resist longitudinal compression of the circumferentially continuous elastomeric outer tube along the entire length of the sleeve.

13. The system according to claim 10, characterized in that The one or more support elements are formed of a biocompatible material and have a k value substantially equal to or greater than 1, wherein k is represented by the following formula: k = F / δ / l, where: k = longitudinal stiffness, in Newtons / millimeter / meter (N / mm / m) F = applied longitudinal force in Newtons (N) δ = extension, deflection, in millimeters (mm) l = length of the support element in meters (m).

14. The system according to claim 10, characterized in that The circumferentially continuous elastomeric outer tube is formed of a biocompatible material and has a kr value substantially equal to or greater than 1.5, wherein kr is represented by the following formula: kr=ki / k0=(F*δ0) / (F*δi), where: kr = stiffness ratio of the improved elastomer layer to the original layer k0 = longitudinal stiffness of the original elastomer layer (N / mm / m) ki = longitudinal stiffness of the modified elastomer layer (N / m / m / m) F = Applied longitudinal force (N) δ0 = extension of the original elastomer layer, deflection (mm) δi = extension of the modified elastomeric layer, deflection (mm).

15. The system according to claim 10, characterized in that The one or more support elements comprise a material selected from the group consisting of: a fibrous material, a textile, a metal, a metal alloy, a polymer, a mixture thereof or a composite material, the selected material having a modulus of at least 50 times that of the continuous elastomeric layer.

16. The system according to claim 10, characterized in that The circumferentially discontinuous support layer is formed by a combination of a support element and a crescent-shaped polymer material, wherein the support element includes a guide wire or strip composed of any one of stainless steel, Nitinol, or a mixture or composite thereof.

17. A method comprising the steps of: Obtaining an introducer sheath formed by an annular collar defining an opening extending through the collar, the annular collar having a circumferentially retractable elongated sleeve attached thereto, the elongated sleeve attached at a proximal opening of the elongated sleeve and extending longitudinally to define a lumen passageway terminating at a distal opening of the elongated sleeve, the elongated sleeve comprising a circumferentially continuous elastomeric outer tube having two or more layers including a continuous elastomeric layer extending longitudinally and spanning the entire length of the sleeve, and a circumferentially discontinuous support layer bonded to the continuous elastomeric layer and formed by one or more support elements, the support layer bonded around the distal opening and extending longitudinally from the distal opening toward the proximal opening; obtaining an expandable inner sheet; positioning the expandable inner sheet longitudinally within the lumen formed by the circumferentially continuous elastomeric outer tube and in substantial contact with the luminal surface of the circumferentially continuous elastomeric outer tube, Thereby, the circumferentially discontinuous support layer is configured to resist longitudinal compression of the circumferentially continuous elastomeric outer tube.

18. The method according to claim 17, characterized in that The following steps are involved: obtaining a dilator having a dilator tip having a larger diameter than a distal opening of the elongated sleeve; The dilator tip is passed through the lumen formed by the expandable inner sheet and along the length of the circumferentially retractable elongate sleeve.

19. The method according to claim 18, characterized in that The following steps are involved: The dilator tip and introducer sheath are passed through the vessel wall.

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