Improved introducer sheath

Abstract

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

Description

[Technical field]

[0001] The technical field relates generally to introducer sheath devices for insertion into the body to provide intravascular access for various medical devices, including, but not limited to, all arterial and vasculature access, abdominal and thoracic, cerebrospinal, genitourinary and gynecological, upper gastrointestinal and colorectal surgery.

[0002] Embodiments generally provide an improved introducer sheath that resists axial compression of the sheath during insertion while not restricting the radial expansion and / or flexibility of the sheath. [Background technology]

[0003] Vascular introducer sheaths are common in endovascular procedures such as transcatheter aortic valve replacement (TAVR), angioplasty, and stenting to facilitate access to the vascular system for the introduction of removable devices such as wires, balloons, and pressure transducers, as well as the introduction and placement of implantable devices such as mechanical aortic valves and stents.

[0004] A vascular introducer sheath typically consists of a single or double layer hollow radial cuff or sleeve through which devices may be threaded after the introducer sheath has been inserted, manipulated, and positioned within the patient's vasculature. The sleeve terminates at one end in a radial collar that is positioned on the patient's skin and within the opening to the blood vessel. The collar typically contains a permeable seal that allows other medical devices to access and withdraw from the blood vessel while avoiding significant bleeding of the patient, and may also include one or more ports that allow fluids to be infused through the sleeve cavity and into the patient's vascular system.

[0005] If 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 that the sleeve will unintentionally compress, fold, wrinkle, or collapse during insertion due to shear forces between the insertion point and the outermost layer, or between the arterial wall and the outermost layer.

[0006] Single-layer introducer sheaths can impede insertion or create blockages within the artery that can prevent passage of the medical device, while dual-layer introducer sheaths expose the inner layer during insertion, creating additional hazards for the patient, including exposure to sharp edges and potential arterial injury from shear forces between the arterial wall and the inner layer.

[0007] As a result, in such a scenario, patients may experience excessive bleeding during or immediately after surgery, prolonged recovery times, excessive scarring or scar tissue at the insertion site, the need for more extensive or longer-term pain management after surgery, and in extreme cases, death.

[0008] Thus, there is a need for an improvement in such introducer sheaths that prevents axial compression or folding back during insertion while not unduly restricting the radial expansion and / or flexibility of the introducer sheath.

[0009] Such an improved introducer sheath is expected to improve the safety of medical procedures and reduce the incidence of failure during insertion of the introducer sheath. Summary of the Invention [Means for solving the problem]

[0010] In various aspects, embodiments of the present invention relate to an introducer sheath for protecting a luminal surface of a blood vessel, the introducer sheath including an annular collar defining an opening extending therethrough, a circumferentially contractible elongate sleeve attached to the annular collar, the elongate sleeve attached at a proximal opening of the elongate sleeve and defining a longitudinally extending lumen channel terminating at a distal opening of the elongate sleeve, the elongate sleeve including a circumferentially continuous elastomeric outer tube having two or more layers including an elastomeric layer extending longitudinally across the length of the sleeve and a circumferentially discontinuous support layer, the circumferentially discontinuous support layer being formed from one or more support elements extending longitudinally from the distal opening towards the proximal opening, the elastomeric outer tube having a smooth inner surface having a substantially round or circular cross-section.

[0011] This design ensures that the inner layer provided in the lumen channel moves 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, providing easy expansion and contraction. In particular, the smooth, circular nature of the inner surface provides a number of advantages. First, it helps to distribute the forces acting on the element more evenly, reducing the risk of localized wear and tear. Second, it maximizes the amount of contact surface area between the inner layer and the tube, which reduces friction and wear. Finally, it allows for a more consistent and predictable movement of the inner layer within the tube.

[0012] The term "round" should be understood herein to refer to a shape consisting of a curve that completely encloses a space. The term "substantially circular" should be understood herein to refer to a shape that closely approximates a perfect circle. Generally, a substantially circular shape has a uniform diameter throughout and does not exhibit significant bulges, depressions, or irregularities. The term may also encompass slightly elliptical or oval shapes, so long as it maintains a high degree of symmetry and overall circularity. For example, a shape is considered to be substantially circular if the deviation from a perfect circle does not exceed some predetermined tolerance level. For example, the deviation from the average diameter may always be less than 10%, 5%, 2%, or 1% of the average thickness of the elastomeric outer tube, or less than 0.05, 0.02, or 0.01 mm.

[0013] In a preferred embodiment, the support element or elements include a substantially crescent-shaped profile to increase section modulus without increasing thickness and are fabricated from polymeric materials known in the art.

[0014] In alternative embodiments, the support element or elements include wires or strips of stainless steel, nitinol, or any one of another materials known in the art that provide tensile stiffness. A preferred circumferentially discontinuous support layer can be formed from a combination of support elements, such as a combination of a wire or strip selected from those that provide tensile stiffness and a crescent-shaped polymeric material.

[0015] In an alternative embodiment, one or more of the support elements have an undulating outer surface to provide substantially rigid ridges and resilient grooves therebetween, allowing each support member to flex and for the radius of the one or more support elements to dynamically change with the radius of the elastomeric layer.

[0016] As used herein, the term "layer" is to be understood as a sheet or similar form of structure that may partially or completely cover another article or object. The term "layer" is not to unduly limit the structure 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 without being stacked or layered, but still be considered two separate layers in themselves.

[0017] As used herein, the term "proximal" should be understood to define a location closer to or to the location of the attachment point, and the term "distal" should be understood to define a location further from or at the opposite end of the attachment point. In the context of the elongate sleeve of the introducer sheath, the attachment point is the annular collar.

[0018] In embodiments, the circumferentially discontinuous support layer may be bonded to the elastomeric layer and / or bonded around the distal opening. The term "bonded" is understood herein to define an arrangement in which two or more separate objects are joined, connected, or linked such that they share a common action, function as a single object, or acquire common properties. This may be by embedding, gluing, welding, sewing, compression, friction, electromagnetic, or any other mechanism known to those skilled in the art. For purposes of illustration, the broad meaning of the term "bonded" as used herein includes, but is not limited to, bonds achieved by interference fit, friction fit, or other mechanical locking features (e.g., utilizing a process that temporarily increases the size of the elastomer). The term "circumferential contraction" is understood herein to define the ability of an object to contract its circumference from an expanded size to its original circumference or any circumference therebetween.

[0019] In a preferred embodiment, the inner surface of the elastomeric outer tube is formed partially by the elastomeric layer and partially by the support layer.

[0020] The elongated sleeve preferably includes a coiled, expandable inner sheet positioned longitudinally within a lumen defined by the circumferentially continuous elastomeric outer tube and positioned substantially in contact with the luminal surface of the circumferentially continuous elastomeric outer tube.

[0021] The one or more support elements preferably extend longitudinally, spanning the entire length of the sleeve, and are bonded to the inner luminal surface of the continuous elastomeric layer, such that 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.

[0022] Preferably, the support element or elements are formed of a semi-rigid material. As used herein, the term "semi-rigid" should be understood to define a material or structure that is somewhat flexible but has some degree of stiffness or rigidity, as opposed to being completely flexible or completely rigid. Preferably, the support element or elements are harder than the elastomeric element. More preferably, the support element or elements are formed of polyurethane.

[0023] Preferably, the one or more support elements are formed of a biocompatible material and have k about equal to or greater than 0.1, where k is represented by the following formula: k=F / δ / l, in the formula; k = longitudinal stiffness (Newton per millimeter per meter (N / mm / m)) F = applied longitudinal force in Newtons (N) δ = elongation, deflection (millimeters (mm)) l = length of the support element in metres (m).

[0024] Preferably, the one or more support elements have k approximately equal to or greater than 2 N / mm / m. More preferably, the one or more support elements have k approximately equal to or greater than 4 N / mm / m.

[0025] The term stiffness according to the above formula describes the ratio between a force applied to a body and the resulting deflection in the direction of that force. This deflection may be due to elastic or inelastic stretching or compression of the material forming the body, or wrinkling or distortion of the shape of the body.

[0026] Preferably, the support element or elements comprise a biocompatible material selected from the group consisting of polyurethane, polyolefin, polypropylene, polyethylene, styrenic polymers, polyester, polycarbonate, fluorinated polymers, polyamide, polyether block amide, polyoxymethylene, polyimide, polyetherimide, polyetheretherketone, stainless steel including titanium and titanium alloys, alloys and blends. They may also be made from fibrous or woven materials including cotton, carbon, aramid, polyamide, polyester.

[0027] Preferably, the circumferentially continuous elastomeric outer tube is formed from a biocompatible material and has a kr approximately equal to or greater than about 1.5, where kr is expressed by the formula: kr=ki / k0=(F*δ0) / (F*δi), in the formula; kr = stiffness ratio of the modified elastomer layer to the original k0 = longitudinal stiffness of the original elastomer layer (N / mm / m) ki = longitudinal stiffness of the modified elastomer layer (N / mm / m) F = applied longitudinal force (N) δ0 = elongation, deflection of the original elastomer layer (mm) δi = elongation, deflection of the modified elastomer layer (mm, in).

[0028] Preferably, the circumferentially continuous elastomeric outer tube has a kr greater than or equal to about 2.5. More preferably, the circumferentially continuous elastomeric outer tube has a kr greater than or equal to about 3.5.

[0029] Longitudinal stiffness is understood to define the ratio between a force applied to the length of a body and the resulting deflection along that length.

[0030] To actually compare the shear stiffness of the support element to the shear stiffness of the elastomeric layer, one would need to apply an equal shear force to each, where the shear force is comparable to the shear force encountered during insertion of the introducer sheath into the incision, measure the deflection of each, and calculate the ratio as described in the formula above.

[0031] 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.

[0032] Preferably, the one or more support elements comprise a material selected from the group consisting of fibrous materials, textiles, metals, metal alloys, polymers, mixtures or composites thereof, and the selected material has an elastic modulus at least 50 times that of the continuous elastomeric layer, e.g., measured according to ASTM D638 or ASTM D412 or ASTM D792.

[0033] More preferably, the one or more support elements comprise a material having a modulus of elasticity at least 200 times that of the continuous elastomeric layer. More preferably, the one or more support elements comprise a material having a modulus of elasticity approximately 300 times that of the continuous elastomeric layer.

[0034] In a further aspect, an embodiment of the present invention is a system for protecting a luminal surface of a blood vessel, comprising an introducer sheath formed from an annular collar defining an opening extending therethrough, with a circumferentially contractible elongate sleeve attached to the annular collar, the elongate sleeve being attached at a proximal opening of the elongate sleeve and defining a longitudinally extending luminal channel terminating at a distal opening of the elongate sleeve, the elongate sleeve being formed of two or more layers including a longitudinally extending continuous elastomeric layer spanning the length of the sleeve and a circumferentially discontinuous support layer. the elongate sleeve is positioned longitudinally within a lumen formed by the circumferentially continuous elastomeric outer tube and includes a coiled expandable inner sheet positioned in substantial contact with the luminal surface of the circumferentially continuous elastomeric outer tube, the circumferentially discontinuous support layer being formed from one or more support elements extending longitudinally from the distal opening towards the proximal opening, and the elastomeric outer tube having a smooth inner surface with a substantially circular cross-section.

[0035] A preferred system further includes a dilator having a dilator tip of a larger diameter than the distal opening of the elongate sleeve, the dilator tip being configured to pass through a lumen formed by the expandable inner sheet along the length of the circumferentially contractible elongate sleeve.

[0036] The one or more support elements preferably extend longitudinally, extending the entire length of the sleeve from or near the distal opening to the proximal opening, or as close to the proximal opening as possible, and are bonded to the inner luminal surface of the continuous elastomeric layer, such that 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.

[0037] In alternative embodiments, the support element or elements may extend partially along the length of the sleeve or may be circumferentially discontinuous along that length. Alternatives to bonding include adhesives, stitching, reflowing materials, co-extrusion, encapsulation (or lamination), or other such methods known in the art that increase friction therebetween.

[0038] The one or more support elements are preferably formed from a biocompatible material and have k approximately equal to or greater than 1, where k is represented by the formula: k=F / δ / l, in the formula; k = longitudinal stiffness in Newtons per millimeter per meter (N / mm / m) F = applied longitudinal force in Newtons (N) δ = elongation, deflection (millimeters (mm)) l = length of the support element in metres (m).

[0039] The circumferentially continuous elastomeric outer tube is alternatively formed from a biocompatible material and has a kr approximately equal to or greater than 1.5, where kr is expressed by the formula: kr=ki / k0=(F*δ0) / (F*δi), in the formula; kr = stiffness ratio of the modified elastomer layer to the original k0 = longitudinal stiffness of the original elastomer layer (N / mm / m) ki = longitudinal stiffness of the modified elastomer layer (N / mm / m) F = applied longitudinal force (N) δ0 = elongation, deflection of the original elastomer layer (mm) δi = elongation, deflection of the modified elastomer layer (mm, in).

[0040] The one or more support elements preferably comprise a material selected from the group consisting of fibrous materials, textiles, metals, metal alloys, polymers, mixtures or composites thereof, where the selected material has an elastic modulus at least 50 times that of the continuous elastomeric layer.

[0041] To provide the necessary structural improvement, the support element should have a higher tensile and flexural modulus than the elastomeric material. As the difference in modulus increases, the required size of the support element decreases, i.e., the effect of the support on the radial expansion stiffness decreases. For example, a titanium support element requires a much smaller cross section than a polyurethane support element to obtain the same longitudinal stiffness effect. The support element also needs to have some flexibility to allow the device to bend inside the patient's body. Buckling resistance must also be considered. A small stainless steel wire may have very good tensile extension resistance, but would require resizing to maintain sufficient compression resistance. In this respect, the material of the support element may have a modulus 10,000 times that of the elastomer (e.g., 40A TPE at 0.2 MPa vs. stainless steel at 210 GPa).

[0042] In a further aspect, an embodiment of the invention provides an introducer sheath comprising a circumferentially continuous elastomeric sleeve having two or more layers including a longitudinally continuous elastomeric layer spanning the entire length of the sleeve and a circumferentially discontinuous support layer bonded to the continuous elastomeric layer and formed from one or more support elements, the circumferentially contractible elongated sleeve having a circumferentially continuous elastomeric layer extending longitudinally and defining a lumen channel terminating at a distal opening of the elongated sleeve, the elongated sleeve being configured to have ... The present invention relates to a method comprising the steps of: obtaining an introducer sheath including an outer tube, the support layer being bonded around a distal opening and extending longitudinally therefrom toward a proximal opening; obtaining an expandable inner sheet; and positioning the expandable inner sheet longitudinally within a lumen formed by a circumferentially continuous elastomeric outer tube, the expandable inner sheet positioned in substantial contact with a 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.

[0043] A preferred method may further include the steps of obtaining a dilator having a dilator tip with a diameter larger than the distal opening of the elongate sleeve, and moving the dilator tip through the lumen formed by the expandable inner sheet and along the length of the circumferentially contractible elongate sleeve.

[0044] A preferred method may further include passing the dilator tip and the introducer sheath through the vessel wall.

[0045] Embodiments are designed to provide an introducer sheath that can be inserted into a blood vessel without wrinkling, folding, or compressing in the direction opposite to the direction of insertion, but while still allowing radial expansion and / or tangential bending.

[0046] The functionality of the embodiment relies on a novel design whereby a support element or spine is incorporated into a circumferentially continuous elastomeric outer sleeve of a contractible elongate sleeve and extends longitudinally. The continuous elastomeric layer is preferably the outermost layer of the elongate sleeve through which the introducer or dilator is threaded and maintains the ability to flex during insertion.

[0047] Since wrinkling, folding, or compression of the elongated sleeve can lead to insertion failure, the incorporation of axially resistant support elements into a circumferentially discontinuous support layer enhances the functionality of the improved introducer sheath.

[0048] The introducer sheath preferably provides a balance of properties including sufficient bendability to navigate the vascular flow network, sufficient rigidity to prevent kinking and buckling, and sufficient elasticity to contract when expanded circumferentially or when unintentionally bent or kinked.

[0049] A design concept according to embodiments is provided by the combination of a continuous elastomeric layer and a circumferentially discontinuous support layer that provide complementary physical properties not available in a single component. In particular, the circumferentially discontinuous support layer of the embodiments provides stiffness and the circumferentially continuous elastomeric outer layer provides elasticity, each providing sufficient bendability for navigation through a patient's vasculature.

[0050] In a preferred embodiment of the invention, the support element or elements are substantially longitudinally straight.

[0051] As used herein, longitudinal is understood to define the direction through the lumen channel defined by the proximal and distal openings, from the proximal end opening to the distal end opening, or from the distal end opening to the proximal end opening.

[0052] The term "radial" is understood herein to define a direction substantially perpendicular to the axial direction.

[0053] The term "substantially linear" is understood herein to define a structure that is generally linear, but may contain some non-linear elements that do not affect the overall orientation and shape on a macroscale.

[0054] The term "substantially in contact" is understood herein to define an assembly in which a significant portion of a surface is in contact with another surface, but not necessarily in contact with the entirety of each surface.

[0055] In a preferred embodiment, the expandable inner sheet is an expandable inner layer formed by wrapping a single sheet onto itself and is characterized as having an outwardly directed annular resistance.

[0056] The expandable inner sheet may include notches, slits, and other sections to improve or modify the physical properties of the elongate sleeve, particularly the bendability, kink resistance, or elasticity of the elongate sleeve.

[0057] The expandable inner sheet may be integrally formed from a substantially homogeneous rigid polymeric material including notches or cutouts. The expandable inner sheet may be configured to be coiled in an overlapping arrangement in its relaxed state and to be helically coiled about the longitudinal axis of the circumferentially contractible elongate sleeve.

[0058] In certain embodiments, the support element may extend partially from the distal end of the circumferentially contractible elongate sleeve to the proximal end of the circumferentially contractible elongate sleeve, and may extend intermittently or continuously therebetween.

[0059] In various embodiments, the profile of the circumferentially continuous elastomeric outer tube along the length of the circumferentially contractible elongate sleeve can be a constant radius or a dynamic radius, thereby forming the sleeve axially tapered or as a tapered portion.

[0060] In preferred constructions and embodiments, the support element is a substantially linear extrusion extending longitudinally from the distal end of the circumferentially contractible elongate sleeve to the proximal end of the circumferentially contractible elongate sleeve.

[0061] The support element may be made from the same or similar material as the circumferentially continuous elastomeric outer tube, with varying consistency or density, may be made from the same material as the expandable inner layer, or may be made from a metal substrate or other material.

[0062] In an alternative embodiment, the circumferentially continuous elastomeric outer tube may be optimized for both containing the support element or for smooth insertion of the introducer sheath into the patient.

[0063] In a preferred embodiment, the support elements may be coupled to an inner surface of a circumferentially continuous elastomeric outer tube and extend longitudinally along the length of the circumferentially shrinkable elongate sleeve from the distal end of the circumferentially shrinkable elongate sleeve to the proximal end of the circumferentially shrinkable elongate sleeve, and may extend intermittently or continuously therebetween.

[0064] In a preferred embodiment, the expandable inner sheet is a helically coiled sheet of stiff polymeric material configured to be coiled in an overlapping arrangement in a relaxed state and to be helically coiled about the longitudinal axis of the circumferentially contractible elongate sleeve.

[0065] In alternative embodiments and configurations, the addition of an expandable inner sheet may be applied to any of the alternative embodiments and configurations of the circumferentially continuous elastomeric outer tube.

[0066] In a preferred embodiment, the expandable inner sheet is expanded by insertion of a dilator or surgical instrument into the lumen of the circumferentially contractible elongate sleeve, the expansion of the expandable inner sheet subsequently expanding the portion of the circumferentially continuous elastomeric outer tube that is not reinforced by the circumferentially discontinuous support layer.

[0067] In a further aspect, the embodiment relates to a method of using an introducer sheath, comprising obtaining an introducer sheath according to any one of the embodiments defined herein, passing a rigid introducer or dilator through an inner lumen channel of the introducer sheath, and introducing the introducer sheath into a blood vessel.

[0068] In a further aspect, the embodiment relates to a method of manufacturing an introducer sheath comprising 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.

[0069] In a further aspect, the embodiment relates to a method of manufacture that may include the additional steps of obtaining a second sleeve layer according to a preferred embodiment of the present invention, attaching the second sleeve layer to a rigid collar at a proximal opening, and disposing the second sleeve layer within a continuous elastomeric layer. [Brief description of the drawings]

[0070] [Figure 1a] 1A and 1B provide front perspective views of prior art introducer sheaths, with FIG. 1(a) providing a front perspective view of a two-layer composite introducer sheath and FIG. 1(b) providing a front perspective view of a single layer sheath. [Figure 1b] 1A and 1B provide front perspective views of prior art introducer sheaths, with FIG. 1(a) providing a front perspective view of a two-layer composite introducer sheath and FIG. 1(b) providing a front perspective view of a single layer sheath. [Figure 2a]Providing side cross-sectional views of the prior art problem at three stages, FIG. 2(a) shows an introducer sheath known in the art prior to insertion, FIG. 2(b) shows the introducer sheath and skin-body interface during insertion, and FIG. 2(c) shows the resulting wrinkling of the skin surface after insertion. [Figure 2b] Providing side cross-sectional views of the prior art problem at three stages, FIG. 2(a) shows an introducer sheath known in the art prior to insertion, FIG. 2(b) shows the introducer sheath and skin-body interface during insertion, and FIG. 2(c) shows the resulting wrinkling of the skin surface after insertion. [Figure 2c] Providing side cross-sectional views of the prior art problem at three stages, FIG. 2(a) shows an introducer sheath known in the art prior to insertion, FIG. 2(b) shows the introducer sheath and skin-body interface during insertion, and FIG. 2(c) shows the resulting wrinkling of the skin surface after insertion. [Diagram 3] FIG. 1 shows a front perspective view of an introducer sheath according to one embodiment of the present invention. [Figure 4a] 4(a) provides a detailed front perspective view according to one embodiment of the present invention, where FIG. 4(a) shows an improvement to the outer layer of one embodiment, and FIG. 4(b) shows the improved outer layer in conjunction with an inner layer. [Figure 4b] 4(a) provides a detailed front perspective view according to one embodiment of the present invention, where FIG. 4(a) shows an improvement to the outer layer of one embodiment, and FIG. 4(b) shows the improved outer layer in conjunction with an inner layer. [Diagram 5] FIG. 4(b) shows a detailed cross-sectional view of the embodiment shown in FIG. 4(a) taken along line AA. [Figure 6a] Detailed cross-sectional side views of various embodiments of the present invention are provided, with FIG. 6(a) showing a support element "in line" with the outer layer of the sleeve, FIG. 6(b) showing a support element "external" to the outer surface of the sleeve, and FIG. 6(c) showing a support element "laminated" within the outer layer of the sleeve. [Figure 6b]Detailed cross-sectional side views of various embodiments of the present invention are provided, with FIG. 6(a) showing a support element "in line" with the outer layer of the sleeve, FIG. 6(b) showing a support element "external" to the outer surface of the sleeve, and FIG. 6(c) showing a support element "laminated" within the outer layer of the sleeve. [Figure 6c] Detailed cross-sectional side views of various embodiments of the present invention are provided, with FIG. 6(a) showing a support element "in line" with the outer layer of the sleeve, FIG. 6(b) showing a support element "external" to the outer surface of the sleeve, and FIG. 6(c) showing a support element "laminated" within the outer layer of the sleeve. [Figure 7a] 7(a) provides side cross-sectional views of a sleeve according to one embodiment of the present invention at three stages during use, with FIG. 7(a) showing the introducer sheath before insertion, FIG. 7(b) showing the improved introducer sheath and skin-body interface during insertion, and FIG. 7(c) showing how the outer layer of the improved introducer sheath passes smoothly through the skin after insertion. [Figure 7b] 7(a) provides side cross-sectional views of a sleeve according to one embodiment of the present invention at three stages during use, with FIG. 7(a) showing the introducer sheath before insertion, FIG. 7(b) showing the improved introducer sheath and skin-body interface during insertion, and FIG. 7(c) showing how the outer layer of the improved introducer sheath passes smoothly through the skin after insertion. [Figure 7c] 7(a) provides side cross-sectional views of a sleeve according to one embodiment of the present invention at three stages during use, with FIG. 7(a) showing the introducer sheath before insertion, FIG. 7(b) showing the improved introducer sheath and skin-body interface during insertion, and FIG. 7(c) showing how the outer layer of the improved introducer sheath passes smoothly through the skin after insertion. [Figure 8] 1 provides a front perspective view of an alternative embodiment of the present invention having multiple support elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0071] Some embodiments of the invention are described in the following examples.

[0072] Referring to FIG. 1, introducer sheaths known in the prior art take one of two general forms. FIG. 1(a) shows a dual-layer introducer sheath 100 known in the art. Such dual-layer introducer sheaths are comprised of three main components: a collar 110, an outer layer 120, and an inner layer 130. The dual-layer introducer sheath shown in FIG. 1(a) is comprised of a coiled inner layer 130 that is loosely coiled within an elastomeric outer layer 120 to allow radial expansion and contraction of the introducer sheath 100, so that the layers can slide over each other to facilitate movement within the vessel. Either the outer layer 120 or the inner layer 130, or both, may be bonded to a collar 110. The collar 110 provides an opening for introducing a dilator into the lumen of the inner layer 130.

[0073] FIG. 1(b) shows an alternative single layer introducer sheath 150, which is well known in the art, and which is comprised primarily of two components: a rigid annular collar 160 and an elongated sleeve 170. The collar 160 is a hollow structure coupled to the elongated sleeve 170. The collar 160 allows for the introduction of material into the lumen 180 of the sleeve 170 through an opening in the sleeve. The annular collar 160 is formed of a rigid material so that a user can manipulate the collar to pass objects or materials into the lumen 180. It terminates in an opening of approximately the same diameter as the opening in the sleeve 170, allowing the sleeve 170 to be placed and secured therein, thereby joining the two components.

[0074] Both forms of prior art introducer sheaths are formed of an elongated flexible tube attached to a collar. The configuration of introducer sheaths 100 and 150 is maintained by a dilator placed within the introducer sheath prior to use during insertion of the introducer sheath into a blood vessel and during introduction of a medical instrument therethrough.

[0075] Because the outer surface of the introducer sheath must be smooth and flexible to avoid catching or tearing fragile blood vessels, in either case, outer layer 120 and sleeve 170 may be formed from materials that are prone to folding or wrinkling during insertion, potentially resulting in failed insertion.

[0076] 2(a)-2(c) show in more detail the problems caused by the prior art devices. FIG. 2 shows the problems with the prior art devices in the form of two layers, but the problems exist for all introducer sheaths made of a smooth and flexible outer material. FIG. 2(a) shows the prior art introducer sheath of FIG. 1(a) before insertion. Prior to introduction into the blood vessel, a dilator 200 is inserted through the collar 110 (not shown) with the tip 210 of the dilator extending through the distal opening 220 and optimally positioned relative to the inner layer 230 and outer layer 240. An opening or incision 250 is made in the skin 260 of the patient 270 to provide an access path for the introducer sheath 100 and the dilator 200 through the arterial wall 280 to the artery 290.

[0077] FIG. 2(b) shows the prior art introducer sheath of FIG. 1(a) during insertion and engagement with the incision 250 and skin 260. The dilator tip 210 is inserted into the incision 250, thereby expanding the opening sufficiently to allow the introducer sheath 100 to access the arterial interior 290. During insertion, the outer layer 240 contacts the skin 260 and the inner surface of the incision 250. Friction against the outer layer 240 and the elasticity of the material forming the outer layer 240 causes the outer layer 240 to wrinkle, compress, and fold in a direction from the distal opening 220 toward the proximal end (not shown). This wrinkle 292 exposes the inner layer 230. Sharp edges formed at the distal opening typically catch and cause injury to the incision 250 or the arterial wall 280 during insertion.

[0078] FIG. 2(c) shows the prior art introducer sheath of FIG. 1(a) during insertion into an artery 290. Once the outer layer 240 wrinkles, the inner layer 230 is exposed. The dilator tip 210 continues to advance within the arterial interior 290, followed by the introducer sheath 100. The wrinkled outer layer 292, 240 may cause damage to the arterial wall 280 from a sharp edge of the inner layer 230 at the distal opening 220 or from catching of the wrinkled outer layer 292, 240 on the arterial wall 280. Such an insertion failure may require the use of a new introducer sheath for a retry of the introducer sheath insertion, which poses further risks to the patient.

[0079] The problems illustrated in Figures 2(a)-2(c) also apply to single-layer introducer sheaths of the type shown in Figure 1(b). Although no sharp inner layers are exposed, wrinkling or folding of the single-layer sleeve can lead to suboptimal insertion, obstruction, and subsequent insertion failure.

[0080] 3 illustrates an improved introducer sheath in accordance with an embodiment of the present invention. The introducer sheath 300 is generally comprised of two main components, a rigid annular collar 310 coupled to an elongated sleeve 320 at the sleeve's proximal end 330. The collar 310 is a hollow, rigid structure configured to allow a user to supply material through the collar to the lumen of the sleeve 320 from an opening in the sleeve at the proximal end 330. The collar 310 may include an inlet (not shown) for allowing fluid to enter the lumen of the introducer sheath 300, and is formed of a rigid material such that a user can manually manipulate the collar to pass objects or materials through an opening 312 formed in the proximal end 332 of the collar 310. The collar 310 terminates at a distal end 334 in a narrowed opening approximately the same diameter as the opening in the sleeve 320 at the sleeve's proximal end 330. The similar diameters of the distal end 334 of the collar 310 and the proximal end 330 of the sleeve allow the sleeve 320 to be placed and secured within the collar 310, thereby joining the two components.

[0081] The sleeve 320 extends away from the proximal end 330 of the collar 310 at key points along its length to facilitate insertion through an incision made 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 facilitate insertion and advancement of the sheath within the vessel. The sleeve 320 is expandable and contractible, allowing a larger dilator, valve, or other medical device to be introduced into the patient through the lumen of the sleeve 320, allowing it to expand around the device and gently press against the vessel lumen wall as it navigates through the vessel, and once the device is removed, it contracts to a size close to its original size for gentle removal from the patient.

[0082] Sleeve 320 is formed from two thin, flexible layers: an elastomeric outer tube 350 and an expandable inner layer 360. Outer elastomeric tube 350 is formed as an elongated tube that maintains within it a coiled, expandable inner sheet that forms expandable inner layer 360. Outer elastomeric tube 350 improves upon the prior art with the addition of a semi-rigid support layer that is configured as an expanded semi-rigid support element 370.

[0083] Outer elastomeric tube 350 is formed from an elastomeric material that is capable of stretching when pressure is applied from the lumen of sleeve 320, but allowing sleeve 320 to return to substantially its original diameter when the internal pressure is relieved. In the relaxed state, outer elastomeric tube 350 has a wall thickness of less than 0.4 mm, and preferably less than 0.2 mm.

[0084] 4(a) and 4(b), the outer elastomeric tube 350 is formed from multiple layers, including an elastomeric layer 410 and a semi-rigid support layer 420. The elastomeric layer 410 is formed from silicone to maximize elasticity and minimize wall thickness, thereby minimizing the risk of damage to the vascular system. However, one of ordinary skill in the art can select other materials for this purpose by evaluating potential materials and selecting a material with appropriate properties. Suitable materials may include materials such as latex rubber or non-latex alternatives, including nitrile rubber, polyvinyl chloride, neoprene, polypropylene and polyisoprene, polyurethane, other thermoplastic elastomers, and the like.

[0085] Elastomeric layer 410 is formed from an extrusion process, during which it is shaped to receive semi-rigid support element 370 within a groove formed longitudinally in luminal surface 430 of elastomeric layer 410. Elastomeric layer 410 and semi-rigid support element 370 are formed into complementary shapes and bonded together by coextrusion, such that the resulting outer elastomeric tube 350 is formed from the assembled and bonded elastomeric layer 410 and semi-rigid support element 370.

[0086] Semi-rigid support element 370 is constructed from a polymeric material. It is formed into a substantially crescent or D-shape and is received within a complementary shape formed by elastomeric layer 410. This shape and the semi-rigid support member extend longitudinally from distal end 340 towards collar 310. In a preferred embodiment, semi-rigid support element 370 extends entirely from distal end 340 to collar 310 without interruption.

[0087] Outer elastomeric tube 350 maintains expandable inner layer 360 in a coiled configuration within the lumen of outer elastomeric tube 350 which contacts and applies an outward force against luminal surface 430 of elastomeric layer 410. When coiled and positioned within luminal surface 430 of elastomeric layer 410, outer elastomeric tube 350 and inner layer 360 form a sleeve lumen 440 to form a composite sheath.

[0088] FIG. 5 shows a cross section of the outer elastomeric tube 350 along the line AA shown in FIG. 4(a). Referring to FIG. 5, the semi-rigid support element 370 has a thickness of 0.1 mm to 0.5 mm and is co-extruded to fill a location along the generally circular profile of the outer elastomeric tube 350, so that the luminal surface 430 of the elastomeric layer 410 is intact and complete. In this configuration, the profile of the outer elastomeric tube 350 protrudes outward, and the profile of the semi-rigid support element 370 protrudes longitudinally. In this configuration, the outermost surface of the semi-rigid support element 370 is surrounded by an elastomeric layer 410 of a thickness less than or similar to the remaining portion of the elastomeric layer 410.

[0089] FIG 4(a) illustrates a preferred configuration and embodiment, and is described in more detail in FIG 5, in which outer elastomeric tube 350 has a substantially circular profile with a smooth, uniform, circular inner surface and protrusions along the length of its outer surface that correspond to the shape of semi-rigid support element 370. As shown in FIGs 4(a) and 4(b), the outermost surface of outer elastomeric tube 350 transitions from a smooth cylinder to a smooth taper, bevel, or chamfer such that the protrusions on the outer surface of outer elastomeric tube 350 do not interfere with the incision or artery during insertion.

[0090] The outermost surface of outer elastomeric tube 350 is of uniform thickness such that it extends over semi-rigid support element 370 revealing its profile at the outermost surface of outer elastomeric tube 350 .

[0091] A range of alternative shapes and configurations may be selected by the skilled artisan depending on the desired properties of the elastomeric material or semi-rigid support element, or ease of manufacture. Particularly useful configurations are shown in Figures 6(a), 6(b), and 6(c).

[0092] Figure 6(a) shows an alternative construction of elastomeric layer 410 and semi-rigid support element 370, where semi-rigid support element 370 remains substantially crescent shaped with an inner radius that matches the inner radius of elastomeric layer 410, such that the combination of these two components results in a substantially circular profile, but without the portions of elastomeric layer 410 that protrude in the preferred embodiment of Figure 5. This alternative construction is formed by bonding or affixing each of the side edges of semi-rigid support element 370 that are in contact with elastomeric layer 410 to elastomeric layer 410 to form a circumferentially continuous outer elastomeric tube 350. In this configuration, the layers are not laminated or bonded on their top and bottom surfaces.

[0093] 6(b) shows an alternative embodiment of elastomeric layer 410 and semi-rigid support element 370, where semi-rigid support element 370 is again substantially crescent shaped, but with an inner radius that matches the outer radius of elastomeric layer 410, and is affixed to its outer surface. In this embodiment, therefore, the inner surface of semi-rigid support element 370 that contacts elastomeric layer 410 needs to be affixed thereto or formed therewith in order to form outer elastomeric tube 350.

[0094] FIG. 6(c) shows an alternative configuration of the elastomeric layers 410 and the semi-rigid support element 370, where the semi-rigid support element 370 remains substantially crescent shaped, but is laminated between two elastomeric layers 410. The outer elastomeric tube 350 has a substantially circular exterior profile, but a portion of that profile is modified to have a protrusion at a larger radius than the remainder of the profile. The outer elastomeric tube 350 has a smooth, substantially circular, continuous interior profile. The semi-rigid support element 370 is housed between the outermost and innermost elastomeric layers 410 and within the protrusion at the exterior surface of the outer elastomeric tube 350.

[0095] By encapsulating or laminating the semi-rigid support element 370 within the material of the outer elastomeric tube 350, the two components can be assembled without the need for bonding or gluing. This configuration is particularly advantageous in cases where bonding of the semi-rigid support element 370 or the elastomeric layer 410 may not be possible, as the semi-rigid support element can be held in the desired position by lamination or pressure rather than bonding. Such cases may arise when the material is chemically incompatible with the bonding agent (e.g., when metallic semi-rigid support elements are used) or when bonding would increase manufacturing costs or difficulty.

[0096] 7(a), 7(b), and 7(c) show solutions to problems of the prior art according to embodiments described herein. FIG. 7(a) shows an improved introducer sheath as described herein prior to insertion. A dilator 200 is inserted through the collar 310 with the dilator tip 210 extending through the distal opening 220 and positioned against the inner layer 230 and outer layer 240, thereby being supported in place by the semi-rigid support element 370. An opening or incision 250 is made in the skin 260 of the patient 270, providing an access path for the introducer sheath 300 and dilator 200 through the arterial wall 280 to the artery 290.

[0097] FIG. 7(b) illustrates the improved introducer sheath of FIG. 4(b) during insertion and engagement with the incision 250 and skin 260. The dilator tip 210 is inserted into the incision 250, thereby dilating the opening sufficiently to allow the introducer sheath 100 access to the arterial interior 290. During insertion, 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, where friction against the outer layer 240 as the dilator 200 passes through the opening or incision 250 is resisted by the semi-rigid support element 370, thereby minimizing wrinkling, compression, and folding of the outer layer 240 in a direction from the distal opening 220 toward the proximal end (not shown). This prevents exposure of the inner layer 230 and any sharp edges that typically form at the distal opening that could catch and damage the incision 250 or artery wall 280 during insertion.

[0098] Figure 7(c) shows the modified introducer sheath of Figure 4(b) during deeper insertion into artery 290. The inner layer 230 is minimally exposed while positioned within artery 290, and its sharp edges are protected by outer layer 220. The chance of failed insertion is reduced, but also the chance of damage to the vessel in the event of removal and reinsertion is reduced.

[0099] The issues illustrated in Figures 7(a)-7(c) also apply to the single layer introducer sheath illustrated in Figure 4(a). Although the inner layer cannot be exposed, the semi-rigid support element 370 similarly reduces the risk that the single layer may wrinkle or fold back, which can lead to suboptimal insertion, blockage, and subsequent failure conditions.

[0100] 8 shows an alternative construction of an improved introducer sheath in which an outer elastomeric tube 850, through which a lumen 840 penetrates, 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 outer elastomeric tube 810 and are constructed like the semi-rigid support elements 870. The outer elastomeric tube 850 is constructed in accordance with the outer elastomeric tube 850 in all other respects. However, the construction of FIG. 8 may be preferred when the material selected for the construction of the elastomeric layer 810 is very thin or very soft. Such materials are commonly preferred for insertion into small containers, for example in ophthalmic microsurgery.

[0101] Elastomeric layer 810 is molded to receive each semi-rigid support element 870, such that the resulting outer elastomeric tube 850 is formed from the assembled elastomeric layer 810 and semi-rigid support elements 870 that maintain the expandable inner layer therein.

[0102] Each semi-rigid support element 870 is positioned along the interior circular profile of outer elastomeric tube 850 such that the inner surface of outer elastomeric tube 850 remains intact and intact. The exterior profile of the exterior surface of outer elastomeric tube 850 is molded by the profile of each semi-rigid support element 870 such that the outermost surface of each semi-rigid support element 870 is covered by elastomeric layer 810 to approximately the same thickness as the remainder of outer elastomeric tube 870.

[0103] For particularly sensitive insertions, the outermost surface of outer elastomeric tube 850 is of uniform thickness such that elastomeric layer 810 is partially thicker between each of the semi-rigid support elements 870 and thinner where it extends over each of the semi-rigid support elements 870, thereby providing outermost and innermost surfaces of outer elastomeric tube 870 that are substantially smooth, circular and uniform.

[0104] Throughout this specification, the word "comprise" or variations such as "comprises" or "comprising" are understood to mean the inclusion of a stated element, integer, or step, or group of elements, integers, or steps, but not the exclusion of other elements, integers, or steps, or groups of elements, integers, or steps.

[0105] It is understood that the terms "fasten" or "fasten," "connect," or "seal," when used alone or with other terms, such as "means," may be used interchangeably when an interpretation of the term may be deemed functionally interchangeable with another term by one of ordinary skill in the art. Moreover, the use of one of the foregoing terms does not exclude an interpretation in which the other term is included.

[0106] Various devices and device components as described herein may be provided in a variety of sizes and / or dimensions as desired. The appropriate size and / or dimensions will vary depending on the specification or field of use of the components to be connected, and may be selected by one of ordinary skill in the art.

[0107] It will be understood that features, elements and / or characteristics described with respect to one embodiment of the present disclosure may, if desired, be used in conjunction with other embodiments of the present invention.

[0108] Although preferred embodiments of the present disclosure have been disclosed for purposes of illustration, those skilled in the art will recognize that various modifications, additions, and substitutions can be made without departing from the scope and spirit of the disclosure and the appended claims.

[0109] When an element or layer is referred to as being "on" or "inside" another element or layer, it is understood that the element or layer can be directly on or inside the other element or layer, or there can be intervening elements or layers. In contrast, when an element is referred to as being "directly on" or "directly inside" another element or layer, there are no intervening elements or layers present.

[0110] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0111] In this specification, terms such as first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or sections, but it is understood that these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or section from another region, layer, or section. Thus, a first element, component, region, layer, or section can be referred to as a second element, component, region, layer, or section without departing from the teachings of the present disclosure.

[0112] Spatially relative terms such as "lower", "upper", "top", "bottom", "left", "right" and the like may be used herein to facilitate describing the relationship of one element or feature to another element or feature as depicted in the figures. It is understood that the spatially relative terms are intended to encompass different orientations of the structure during use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as "lower" relative to other elements or features would be oriented "upper" relative to other elements or features. Thus, the exemplary term "lower" can encompass both an orientation of up and down. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should be interpreted accordingly.

[0113] The terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly dictates otherwise. Furthermore, as used herein, the terms "including," "comprises," and / or "comprising" specify the presence of stated features, integers, steps, operations, elements, and / or components, but are understood not to exclude the presence and addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0114] The presently described embodiments are described herein with reference to, for example, illustrations and / or cross-sectional illustrations that are schematic diagrams of the presently described preferred embodiments (and intermediate structures). As such, variations from the shapes of the illustrations are to be expected as a result, for example, of manufacturing techniques and / or tolerances. Thus, the presently described embodiments should not be construed as limited to the particular shapes of the components illustrated herein but should include, for example, deviations in shapes that result from manufacturing.

[0115] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by a person of ordinary skill in the art to which this description belongs. Terms, such as terms defined in commonly used dictionaries, should be interpreted as having a meaning consistent with the meaning in the context of the relevant art, and it is further understood that they should not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0116] The use of phrases such as "one embodiment," "embodiment," "exemplary embodiment," and the like in this specification means that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the description. The appearances of such phrases in various places in this specification do not necessarily all refer to the same embodiment. Moreover, when a particular feature, structure, or characteristic is described in connection with any embodiment, one of ordinary skill in the art can implement and / or use such feature, structure, or characteristic in connection with other embodiments.

[0117] Embodiments are also intended to encompass or otherwise cover methods of using and making any or all of the above disclosed elements.

[0118] Although the present invention has been described above with reference to specific embodiments, it should be understood that the present invention is not limited to these disclosed embodiments. Many modifications and other embodiments of the present invention will occur to those skilled in the art upon reading the teachings of this disclosure. These are intended to be and are covered by both the disclosure and the appended claims.

[0119] All publications mentioned in this specification are incorporated herein by reference. Any discussion of documents, acts, materials, devices, articles or the like which has been included in this specification is solely for the purpose of describing the background of the invention and is not to be construed as an admission that any or all of such matter constitutes part of the prior art or was common general knowledge in the fields relevant to the invention as it existed in Australia or anywhere else prior to the priority date of each claim in this application.

[0120] It is intended that the scope of the invention be determined by properly interpreting and constructing the appended claims and their legal equivalents, as interpreted by one of ordinary skill in the art in reliance on the disclosures of this specification and the accompanying drawings.

Claims

1. 1. An introducer sheath for protecting a luminal surface of a blood vessel, comprising: an annular collar defining an opening extending therethrough; a circumferentially contractible elongated sleeve attached to the annular collar, the elongated sleeve being attached at a proximal opening of the elongated sleeve and defining a longitudinally extending lumen channel terminating at a distal opening of the elongated sleeve; the elongate sleeve includes a circumferentially continuous elastomeric outer tube having two or more layers including a longitudinally extending elastomeric layer spanning the length of the sleeve and a circumferentially discontinuous support layer; the circumferentially discontinuous support layer is formed from one or more support elements extending longitudinally from the distal opening toward the proximal opening; The elastomeric outer tube has a smooth inner surface with a substantially round cross-section. Introducer sheath.

2. 2. The introducer sheath of claim 1, wherein 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 introducer sheath of claim 1 , wherein an exterior surface of the elastomeric outer tube is formed by the elastomeric layer.

4. 2. The introducer sheath of claim 1, wherein the elongated sleeve includes a coiled, expandable inner sheet positioned longitudinally within a lumen defined by the circumferentially continuous elastomeric outer tube and positioned substantially in contact with a luminal surface of the circumferentially continuous elastomeric outer tube.

5. 2. The introducer sheath of claim 1, wherein the one or more support elements extend longitudinally, extend along the entire length of the sleeve, and are bonded to an interior luminal surface of the continuous elastomeric layer, such that 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 one or more support elements are formed of a biocompatible material and have a k value about equal to or greater than 0.1, where k is represented by the following formula: k=F / δ / l, where; k = longitudinal stiffness (Newtons per millimeter per meter (N / mm / m)) F = applied longitudinal force in Newtons (N) δ = extension, deflection (millimeters (mm)) l = length of the support element in meters (m), The introducer sheath of claim 1 .

7. The circumferentially continuous elastomeric outer tube is formed from a biocompatible material and has a kr value approximately equal to or greater than about 1.5, where kr is expressed by the formula: kr=ki / k0=(F*δ0) / (F*δi), in the formula; kr = stiffness ratio of the modified elastomer layer to the original 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 = elongation or deflection of the original elastomer layer (mm) δi=elongation, deflection of the modified elastomer layer (mm); The introducer sheath of claim 1 .

8. 2. The introducer sheath of claim 1, wherein the one or more support elements comprise a material selected from the group consisting of fibrous materials, textiles, metals, metal alloys, polymers, mixtures or composites thereof, the selected material having an elastic modulus at least 50 times that of the continuous elastomeric layer.

9. 2. The introducer sheath of claim 1, wherein the circumferentially discontinuous support layer is formed from a combination of support elements including wires or strips of any one of stainless steel, nitinol, or a mixture or composite thereof, and a polymeric material formed into a crescent shape.

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

11. 11. The system of claim 10, comprising a dilator having a dilator tip of a larger diameter than the distal opening of the elongate sleeve, the dilator tip configured to pass through a lumen formed by the expandable inner sheet along the length of the circumferentially contractible elongate sleeve.

12. 11. The system of claim 10, wherein the one or more support elements extend longitudinally, extend along the entire length of the sleeve, and are bonded to an interior luminal surface of the continuous elastomeric layer, such that 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 one or more support elements are formed of a biocompatible material and have a k value about equal to or greater than 1, where k is represented by the following formula: k=F / δ / l, where; k = longitudinal stiffness in Newtons per millimeter per meter (N / mm / m) F = applied longitudinal force in Newtons (N) δ = extension, deflection (millimeters (mm)) l = length of the support element in meters (m), The system of claim 10.

14. The circumferentially continuous elastomeric outer tube is formed of a biocompatible material and has a kr value approximately equal to or greater than 1.5, where kr is expressed by the formula: kr=ki / k0=(F*δ0) / (F*δi), in the formula; kr = stiffness ratio of the modified elastomer layer to the original k0 = longitudinal stiffness of the original elastomer layer (N / mm / m) ki = longitudinal stiffness of the modified elastomer layer (N / mm / m) F = applied longitudinal force (N) δ0 = elongation or deflection of the original elastomer layer (mm) δi=elongation, deflection of the modified elastomer layer (mm); The system of claim 10.

15. 11. The system of claim 10, wherein the one or more support elements comprise a material selected from the group consisting of fibrous materials, textiles, metals, metal alloys, polymers, mixtures or composites thereof, the selected material having an elastic modulus at least 50 times that of the continuous elastomeric layer.

16. 11. The system of claim 10, wherein the circumferentially discontinuous support layer is formed from a combination of support elements including wires or strips of any one of stainless steel, nitinol, or a mixture or composite thereof, and a polymeric material formed into a crescent shape.

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

18. obtaining a dilator having a dilator tip with a diameter larger than the distal opening of the elongate sleeve; moving the dilator tip through a lumen formed by the expandable inner sheet and along the length of the circumferentially contractible elongate sleeve; 20. The method of claim 17, comprising:

19. Passing the dilator tip and introducer sheath through the vessel wall.

20. The method of claim 18, comprising:

Images