Medical kink resistant peel away sheath

Abstract

To provide devices and methods for providing a kink-resistant peel away sheath.SOLUTION: A device includes a sheath 300 for insertion into a vasculature of a patient. The sheath comprises a sheath body having an outer surface, a longitudinal axis and a lumen 108 formed through the sheath body 105. The sheath body comprises an inner layer 110 arranged about the longitudinal axis, an outer layer 120 coaxially arranged with the inner layer, and a support layer 130 positioned between the inner and outer layers, where the inner, outer and support layers are laminated together to form the sheath body. The sheath also comprises at least one shear line 144 positioned beneath the outer surface of the sheath body, and configured to facilitate the longitudinal separation of the sheath body along the at least one shear line.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit under 35 USC § 119(e) of U.S. Provisional Application No. 62 / 777,598, filed December 10, 2018, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] background Intravascular medical devices may include, but are not limited to, Impella® pumps, extracorporeal membrane oxygenation (ECMO) pumps, and balloon pumps. Impella® pumps may further include Impella 2.5® pumps, Impella 5.0® pumps, Impella CP® pumps, and Impella LD® pumps, all by Abiomed, Inc. of Danvers, MA. Peel-away introducers are disposable medical devices used to deliver medical devices into a patient's vasculature during cardiac catheterization procedures or other medical settings. The medical device is typically threaded into a peel-away sheath prior to insertion into the patient's vasculature. Once the medical device is positioned, the peel-away introducer may be removed. Such removal is necessary to allow other medical devices larger than the lumen in the sheath (and hub) to be inserted into the patient's arteriotomy. A standard peel-away introducer includes a proximal plastic hub connected to a sheath that allows the sheath to be torn apart. A medical device may be inserted through the plastic hub and into the sheath through which the device may be placed within the patient. Intravascular medical devices, such as intracardiac blood pumps, catheters, guidewires, leads, etc., may be introduced into the patient's vasculature through the peel-away introducer.

[0003] In one approach, the physician tears the introducer sheath by cracking the plastic introducer hub (if present) and peeling away the shaft of the sheath body. To tear the introducer sheath, a separation force must be applied to the sheath body. The physician then grasps the hub and breaks it along the axial notch or crease at the proximal end of the sheath. The sheath can tear along its long axis and peel away axially along the shear line or crease on one or both sides of the sheath. The introducer's peel-away sheath allows the introducer to be removed or removed without disturbing or removing the medical device after it has been inserted through the introducer and into the patient.

[0004] In a typical manufacturing technique, the peel-away sheath is formed from a single extruded plastic tube. Such extruded plastic tube is typically rigid and is positioned within the patient using a dilator. Once inserted within the patient's vasculature, the dilator is removed. In complex medical procedures, it may be necessary to reposition the sheath or apply additional lateral force (pushing force) to the sheath, for example to further secure the sheath to the patient. This may cause the extruded tube to kink or bend, thereby blocking the sheath passageway, which further complicates the medical procedure. Furthermore, due to the nature of currently available sheaths, additional procedures are required to prevent the sheath from kinking. Such procedures include suturing or taping the sheath in the desired position to prevent the sheath from collapsing or bending. The additional steps complicate the use of the sheath and also increase the overall profile of the procedure. Summary of the Invention

[0005] overview Approaches are disclosed herein to address various problems and shortcomings of the state of the art as discussed above. More specifically, devices and methods are disclosed herein for providing a kink-resistant peel-away sheath. In one embodiment, the device of the present invention comprises a sheath for insertion into a patient's vasculature. The sheath comprises a sheath body having an outer surface, a longitudinal axis, and a lumen formed therethrough. The sheath body comprises an inner layer arranged about the longitudinal axis, an outer layer arranged coaxially with the inner layer, and a support layer positioned between the inner layer and the outer layer; the inner layer, the outer layer, and the support layer are laminated together to form the sheath body. The sheath also comprises at least one shear line formed in the sheath body; the at least one shear line is positioned below an outer surface of the sheath body and configured to facilitate longitudinal separation of the sheath body along the at least one shear line.

[0006] The support structure allows the sheath to withstand large pushing forces without the formation of kinks. This results in a more pushable sheath while maintaining flexibility for complex intravascular procedures. Additionally, the formation of shear lines in the sheath structure allows for easy separation of the kink-resistant sheath.

[0007] In some embodiments, the support layer is arranged coaxially between the inner layer and the outer layer. Such a coaxial arrangement allows each layer to have a similar thickness around the circumference of the sheath body. In certain embodiments, the inner layer and the outer layer comprise an extrusion. In some embodiments, the inner layer and the outer layer are made of any one of polyether block amide (such as PEBAX or PebaSlix®), a polyethylene material, a polytetrafluoroethylene (PTFE) material, a high density polyethylene (HDPE) material, a medium density polyethylene (MDPE) material, and a low density polyethylene (LDPE) material.

[0008] In some embodiments, the shear lines may be linear or non-linear. In certain embodiments, each shear line may be formed by a monofilament positioned between the inner layer and the support layer and / or between the support layer and the outer layer before the inner layer, outer layer, and support layer are laminated. In further embodiments, the monofilament may be made of a material with a melting point that is higher than, equal to, or lower than the melting point of the material used in the inner and outer layers. In some embodiments, the monofilament extends longitudinally along the sheath body. In certain embodiments, the monofilament extends helically along the longitudinal axis. Such variations allow for the creation of kink-resistant sheaths that meet the needs of physicians based on the medical procedure at hand.

[0009] In certain embodiments, the monofilament may comprise a rod made from any one of polyetheretherketone (PEEK), polyether block amide (such as PEBAX or PebaSlix®), polyethylene material, polytetrafluoroethylene (PTFE) material, nylon, high density polyethylene (HDPE) material, medium density polyethylene (MDPE) material, low density polyethylene (LDPE) material, and stainless steel.

[0010] In some embodiments, the monofilament may be fused to the support layer. In further embodiments, the sheath may include two shear lines, thereby facilitating tearing of the kink-resistant sheath. In certain embodiments, the monofilament may be radially spaced 180° apart about the longitudinal axis of the sheath. In further embodiments, a void may be created between the monofilament and at least one of the inner layer and the outer layer. In some embodiments, the monofilament may be removable from the sheath body. Removal of the monofilament leaves a void in the sheath body, which allows the kink-resistant sheath to easily split.

[0011] In certain embodiments, the at least one shear line may comprise at least one weak joint formed by splitting the sheath body along its longitudinal axis; and reflowing the split sheath body to create the at least one weak joint that reconnects the split sheath bodies. In some embodiments, the at least one shear line may comprise multiple weak joints formed by splitting the sheath body into multiple portions along its longitudinal axis; inserting a thin extruded layer into the lumen of the sheath body; and reflowing the split sheath body with the thin extruded layer to create the multiple weak joints that reconnect the split sheath bodies. Such an alternative to forming a shear line results in a kink-resistant sheath that is easier to fabricate, but does not kink or collapse the sheath upon application of greater compression forces. In further embodiments, the support layer may comprise a braid or coil. In some embodiments, the support layer may comprise a spiral laser-cut layer. In certain embodiments, the sheath body may be pre-scored along the shear line, which facilitates separation of the sheath body as less force is required for the physician to tear the sheath apart.

[0012] In some embodiments, the support layer may comprise at least one S-shaped wire having turns held in an interlocking orientation by a removable mandrel. In other embodiments, the support layer may comprise a plurality of S-shaped wires held in an interlocking orientation by a corresponding number of removable mandrels. Such S-wires provide an alternative support structure in which the interlocking wires help to hold the S-wires in place during lamination and also help to provide shear lines upon removal from the sheath body after lamination.

[0013] In certain embodiments, the at least one shear line may be positioned within at least one of the inner layer, the outer layer, and the support layer. In other embodiments, the at least one shear line may extend longitudinally along at least a portion of the length of the sheath body. In some embodiments, the at least one shear line may comprise any one of a void, a frangible seam, and a frangible joint formed within the sheath body. In certain embodiments, the support layer may be made from any one of polyetheretherketone (PEEK), polyether block amide (such as PEBAX or PebaSlix®), a polyethylene material, a polytetrafluoroethylene (PTFE) material, nylon, a high density polyethylene (HDPE) material, a medium density polyethylene (MDPE) material, a low density polyethylene (LDPE) material, and stainless steel.

[0014] In another aspect, a method for making a kink resistant peel away sheath is described. The method includes providing a tubular inner layer having a longitudinal axis and a lumen formed therethrough. The method then includes providing an outer layer arranged coaxially with the inner layer. The next step in the method is providing a support layer laminated between the inner layer and the outer layer to form a sheath body. The method also includes reflowing the sheath body to fuse the inner layer, the outer layer, and the support layer. The next step in the method is forming at least one shear line positioned below an outer surface of the sheath body, the at least one shear line configured to facilitate longitudinal separation of the sheath body along the at least one shear line.

[0015] In some embodiments, the method further includes arranging a support layer coaxially between the inner layer and the outer layer. In other embodiments, the method includes inserting at least one monofilament between the inner layer and the support layer or between the support layer and the outer layer prior to reflowing the sheath body. In certain embodiments, the method also includes removing the monofilament after reflowing. In some embodiments, the monofilament may comprise a rod made of any one of polyetheretherketone (PEEK), polyether block amide (such as PEBAX or PebaSlix®), polyethylene material, polytetrafluoroethylene (PTFE) material, nylon, high density polyethylene (HDPE) material, medium density polyethylene (MDPE) material, low density polyethylene (LDPE) material, and stainless steel. In certain embodiments, the sheath comprises two shear lines.

[0016] In some embodiments, the method may further include scoring the sheath body prior to the reflowing step. In other embodiments, the method may further include radially separating the monofilaments 180° about the longitudinal axis. In certain embodiments, the method additionally includes splitting the sheath body along the longitudinal axis; and reflowing the split sheath body to create at least one weakened seam that reconnects the split sheath body. In some embodiments, forming each shear line in the sheath body further includes splitting the sheath body along the longitudinal axis; inserting a thin extruded layer into the lumen of the sheath body; and reflowing the split sheath body to create at least one weakened seam that reconnects the split sheath body.

[0017] In another embodiment, the step of providing a support layer laminated between the inner layer and the outer layer further includes interlocking a plurality of S-shaped wires wrapped around the inner layer with a corresponding number of removable mandrels, where each mandrel is removable to form a shear line in the sheath body.

[0018] In a further aspect, a sheath body is provided having an outer surface, a longitudinal axis, and a lumen formed therethrough. Also provided is a support means laminated within and extending longitudinally along the sheath body, and a shear means positioned below the outer surface of the sheath body, the sheath means configured to facilitate longitudinal separation of the sheath body along the at least one shear means.

[0019] In some embodiments, the support means may comprise a support layer. In other embodiments, the shear means may comprise at least one shear line. In further embodiments, the sheath body may comprise an inner layer arranged about the longitudinal axis and an outer layer arranged coaxially with the inner layer, and the support means is laminated between the inner layer and the outer layer. In some embodiments, the support means may be arranged coaxially between the inner layer and the outer layer. In other embodiments, the inner layer and the outer layer may comprise an extrusion.

[0020] In certain embodiments, the inner and outer layers may be made from any one of polyether block amides (such as PEBAX or PebaSlix®), polyethylene materials, polytetrafluoroethylene (PTFE) materials, high density polyethylene (HDPE) materials, medium density polyethylene (MDPE) materials, and low density polyethylene (LDPE) materials.

[0021] In some embodiments, the at least one shear line may be linear or non-linear. In certain embodiments, each shear line may be formed by a monofilament positioned between the inner layer and the support layer and / or between the support layer and the outer layer before the inner layer, the outer layer, and the support layer are laminated. In other embodiments, the monofilament may be made of a material with a melting point higher than, equal to, or lower than the melting point of the material used in the inner and outer layers. In some embodiments, the monofilament may extend longitudinally along the sheath body. In certain embodiments, the monofilament may extend helically along the longitudinal axis.

[0022] In further embodiments, the monofilament may comprise a rod made from any one of polyetheretherketone (PEEK), polyether block amide (such as PEBAX or PebaSlix®), polyethylene material, polytetrafluoroethylene (PTFE) material, nylon, high density polyethylene (HDPE) material, medium density polyethylene (MDPE) material, low density polyethylene (LDPE) material, and stainless steel. In some embodiments, the monofilament may be fused to the support layer. In other embodiments, the sheath may comprise two shear lines. In other embodiments, the monofilament may be radially spaced 180° apart about the longitudinal axis. In certain embodiments, a gap may be created between the monofilament and at least one of the inner layer and the outer layer. In some embodiments, the monofilament may be removable from the sheath body.

[0023] In some embodiments, the at least one shear line may comprise at least one weakened seam formed by splitting a sheath body along a longitudinal axis; and reflowing the split sheath body to create the at least one weakened seam reconnecting the split sheath bodies. In other embodiments, the at least one shear line may comprise multiple weakened seams formed by splitting a sheath body along a longitudinal axis into multiple portions; inserting a thin extruded layer into a lumen of the sheath body; and reflowing the split sheath body with the thin extruded layer to create the multiple weakened seams reconnecting the split sheath bodies.

[0024] In certain embodiments, the support layer may comprise a braid or coil. In other embodiments, the support layer may comprise a spirally wound laser cut layer. In further embodiments, the sheath body may be pre-scored along the shear line. In some embodiments, the support layer may comprise at least one S-shaped wire having convolutions held in an interlocking orientation by a removable mandrel. In other embodiments, the support layer may comprise a plurality of S-shaped wires held in an interlocking orientation by a corresponding number of removable mandrels.

[0025] In some embodiments, the at least one shear line may be positioned within at least one of the inner layer, the outer layer, and the support layer. In certain embodiments, the at least one shear line may extend longitudinally along at least a portion of the length of the sheath body. In further embodiments, the at least one shear line may comprise any one of a void, a weak seam, and a weak joint formed within the sheath body.

[0026] In other embodiments, the support layer may be made from any one of polyetheretherketone (PEEK), polyether block amide (such as PEBAX or PebaSlix®), a polyethylene material, a polytetrafluoroethylene (PTFE) material, nylon, a high density polyethylene (HDPE) material, a medium density polyethylene (MDPE) material, a low density polyethylene (LDPE) material, and stainless steel.

[0027] In another aspect, a method of using the aforementioned sheath to treat a patient with a ventricular assist device is provided, the method comprising inserting the sheath into an arteriotomy of the patient at a first position, the method then comprises separating the sheath by splitting the sheath body, and finally, the method comprises inserting the ventricular assist device into the arteriotomy of the patient at the first position. [Brief description of the drawings]

[0028] These and other objects and advantages will become apparent from the following detailed description considered in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout.

[0029] [Figure 1] 1 illustrates an exemplary peel away sheath according to one embodiment of the present disclosure. [Diagram 2] 2 illustrates an exemplary cross-sectional view of the peel-away sheath of FIG. 1. [Diagram 3] 3 illustrates the exemplary peel away sheath of FIGS. 1 and 2 being separated along a shear line in the sheath body. [Figure 4] 1 illustrates an exemplary peel away sheath separated along a helical shear line in the sheath body according to one embodiment of the present disclosure. [Diagram 5]FIGURE 5A illustrates an exemplary support layer of the peel-away sheath of FIGURE 1 having two S-shaped wires held in an interlocking orientation by two removable mandrels according to one embodiment of the present disclosure, and FIGURE 5B illustrates removal of the mandrels of the support layer illustrated in FIGURE 5B to separate the sheath body. [Figure 6] 1 illustrates an exemplary cross-sectional view of a further embodiment of a kink-resistant peel-away sheath of the present disclosure with a separated and reflowed sheath portion. [Figure 7] 13A-13C show exemplary cross-sectional views of other various aspects of the kink-resistant peel-away sheath of the present disclosure with the sheath portion reflowed over a separated thin extruded layer. [Figure 8] 1 shows an exemplary flow chart of a method for making a kink-resistant peel-away sheath according to one embodiment of the present disclosure. [Figure 9] 1 shows an exemplary flow chart of a method for using a kink-resistant peel-away sheath according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Detailed Description Certain exemplary embodiments will be described so that the devices and methods described herein may be generally understood. Although the embodiments and features described herein are specifically described for use in connection with a kink-resistant peel-away sheath for use in an intravascular procedure involving a ventricular assist device, it will be understood that all components and other features outlined below may be combined with one another in any suitable manner and may be adapted and applied to other types of procedures requiring a kink-resistant peel-away sheath.

[0031] The devices and methods described herein use a sheath structure that includes inner and outer layers and a support layer to strengthen the sheath. These layers are subjected to a heat treatment (reflow) where the layers are laminated together to produce a laminate of layers. Such a reinforced laminate structure allows the sheath to be subjected to a larger pushing force without causing the sheath to kink or collapse.

[0032] The sheath may also include a monofilament or rods, such as nylon rods, inserted into the layered structure of the sheath body and positioned between the outer layer and the support layer. During the lamination process, the monofilament does not fuse to the inner and outer layers of the sheath body, allowing for removal after heat treatment. When the monofilament is removed, a void remains in its place. Such a void thins the sheath body in the immediate vicinity of the void, thereby forming a shear line within the sheath body near which the sheath separates or tears when subjected to a separation force, such as when the physician pulls the sheath apart. The sheath body tears along the shear line in a controlled and predetermined manner.

[0033] In other embodiments, the shear line may be formed by a frangible seam. Here, the laminated sheath body may be split into at least two parts along the longitudinal axis. The split portions of the sheath body may then be reassembled and reflowed once more such that a frangible seam is formed between the two split portions of the sheath body (e.g., by melting the split portions). The frangible seam is formed within the sheath body and below the outer surface of the sheath body. Such a frangible seam requires less separation force to break, thereby allowing for easy tearing of the reinforced sheath. In a further embodiment, the split portions of the seam are reassembled onto the single extruded layer. The reassembled structure may then be subjected to an additional reflow process such that the split portions of the sheath body are fused to the outer surface of the single extruded layer, thereby forming a frangible connection. Similar to a seam, the frangible connection is thinner than the thickness of the layered sheath body and therefore requires less separation force to break the connection, thereby allowing for easy tearing of the reinforced sheath. A frangible connection is also formed below the exterior surface of the sheath body.

[0034] The reinforced laminate construction of the sheath body and the shear lines formed thereon provide a flexible peel away sheath that can withstand greater forces, such as, but not limited to, pushing forces. The increased pushability of such a sheath allows the sheath to be used without the need for a hub as described above, thereby reducing the profile of the kink resistant peel away sheath.

[0035] 1 illustrates a close-up view of an exemplary kink-resistant sheath 100 according to one embodiment of the present disclosure. The sheath 100 is suitable for insertion into an arteriotomy of a patient, such as the femoral artery. The sheath 100 comprises a sheath body 105 extending along a longitudinal axis 106 and having a lumen 108 extending therethrough. In certain embodiments, the sheath body 105 may be tubular with a circular cross-section, although the sheath body 105 may be of any shape and configuration.

[0036] The lumen of the sheath body 105 is open for the passage of a ventricular assist device, such as a percutaneous pump (not shown). One example of such a percutaneous pump is the Impella 2.5™ pump system by Abiomed, Inc. of Danvers, Massachusetts. Such pumps generally include a catheter body with a pump head at the distal end of the catheter body and a handle at the proximal end of the catheter body. In most cases, the pump head has a diameter larger than that of the catheter body. It will be understood that although a percutaneous heart pump is described herein, any other percutaneous or intravascular medical device may be used in conjunction with the present disclosure.

[0037] The sheath body 105 includes an inner layer 110 arranged along a longitudinal axis 106 of the sheath body 105. The inner layer 110 may include an extruded layer having a lumen formed therethrough. The lumen of the inner layer 110 forms the lumen of the sheath body 105. The inner layer 110 may include a first material. In some embodiments, the inner layer 110 may be tubular with a circular cross-section, an inner surface, and an outer surface. The sheath body 105 may also include an outer layer 120. Similar to the inner layer 110, the outer layer 120 may include an extruded layer. The outer layer 120 may include a second material. In some embodiments, the outer layer 120 may be tubular with a circular cross-section, an inner surface, and an outer surface. The outer layer 120 is arranged about the longitudinal axis 106 of the sheath body 105 such that the outer layer 120 is coaxial with the inner layer 110. In this configuration, the outer layer 120 is concentrically arranged around the inner layer 110 along the length of the sheath body 105. In some embodiments, the outer layer 120 may be concentrically arranged around the inner layer 110 along a portion of the length of the sheath body 105.

[0038] The sheath 100 further includes a support layer 130 arranged between the inner layer 110 and the outer layer 120. In this configuration, the support layer 130 is effectively sandwiched between the first layer 110 and the second layer 120. The support layer 130 may include a braided structure that reinforces the inner layer 110 and the outer layer 120 of the sheath body 105. The support structure 130 may be tubular with a circular cross-section. In some embodiments, the support layer 130 may extend along the length of the sheath body 105. In other embodiments, the support layer 130 may extend along a portion of the length of the sheath body 105. Although FIG. 1 illustrates the support layer 130 as a tubular braided structure, it will be understood that the support layer 130 may include other structures, such as the support layer of FIGS. 5A-5B in the following description. For example, the support structure 130 may comprise a tubular coil or at least one S-wire wound around the outer surface of the inner layer 110 releasably interlocked with a corresponding number of mandrels. Such reinforcement prevents the sheath 110 from kinking while maintaining its flexibility when inserted or pushed into the patient's vasculature. Additionally, the support layer 130 may comprise a laser cut extrusion. The laser cut extrusion may include a spiral laser cut layer. The laser cut extrusion may be cut according to any pattern that enhances the pushability of the sheath while maintaining its flexibility. By pushability, it is meant that the construction of a peel away sheath according to the present disclosure allows a greater pushing force to be applied to the sheathing when inserting the sheathing into the patient's vasculature without forming kinks or bends in the sheathing. The support structure may comprise a third material.

[0039] In some embodiments, the thickness of the inner layer 110 may be equal to the thickness of the outer layer 120. In other embodiments, the inner layer 110 and the outer layer 120 may be of different thicknesses to control the stiffness of the sheath 100. Additionally, in some embodiments, the support layer 130 may be thinner than the inner layer 110 and the outer layer 120. In certain embodiments, the inner layer 110 and the outer layer 120 may comprise an extrusion.

[0040] In some embodiments, the first material used for the inner layer 110 may comprise any one of a polyether block amide (such as PEBAX or PebaSlix®), a polyethylene material, a polytetrafluoroethylene (PTFE) material, a high density polyethylene (HDPE) material, a medium density polyethylene (MDPE) material, and a low density polyethylene (LDPE) material. In some embodiments, the second material used for the outer layer 120 may comprise the first material; that is, the inner layer 110 and the outer layer 120 may be made of the same material. Furthermore, in certain embodiments, the third material used for the support layer 130 may comprise any one of a polyether ether ketone (PEEK), a polyether block amide (such as PEBAX or PebaSlix®), a polyethylene material, a polytetrafluoroethylene (PTFE) material, a nylon, a high density polyethylene (HDPE) material, a medium density polyethylene (MDPE) material, a low density polyethylene (LDPE) material, and a stainless steel.

[0041] FIG. 1 also shows two monofilaments or rods 140, 145 arranged with the support layer 130 between the inner layer 110 and the outer layer 120. In some embodiments, the rods 140, 145 are arranged between the outer layer 120 and the support layer 130. In other embodiments, the rods 140, 145 may be arranged between the inner layer 110 and the support layer 130. The rods 140, 145 may be radially symmetric about the longitudinal axis 106 of the sheath body 105. As shown in FIG. 1, the rods 140, 145 are radially 180° apart from each other about the longitudinal axis 106 of the sheath 100. In certain embodiments, the rods 140, 145 may be made of the same material type as the support layer 130; i.e., the rods 140, 145 may be made of a third material as defined above. In some embodiments, the rods 140, 145 may comprise nylon rods extending longitudinally about the axis 106. It will be understood that although two rods are shown in Figure 1, any number of rods may be included within the sheath 100 according to the present disclosure. Additionally, in the following description, nylon rods are illustrated in various embodiments. However, it will be understood that rods of any material type may be used, as defined by the third material type.

[0042] It should be noted that the use of different materials for the rods than those used for the inner, outer, and support layers results in spaces immediately adjacent the rods within the sheath 100 after lamination. In some embodiments, such spaces facilitate removal of the rods while the sheath is in use.

[0043] In certain embodiments, the layered arrangement depicted in FIG. 1 is subjected to a reflow cycle in which the layered configuration is exposed to heat based on a temperature profile. The heat may be implemented as a thermal zone moving along the length of the sheath body 105. The heat treatment causes the inner layer 110, the outer layer 120, and the support layer 130 to laminate together to form the sheath body 105 as a single layer. The lamination of the layers increases the flexibility and pushability of the sheath 100 while preventing the formation of kinks in the sheath body 105. Although the reflow causes the inner layer 110, the outer layer 120, and the support layer 130 to laminate together, the use of different material types for these layers prevents the support layer 130 from fusing with the inner layer 110 and the outer layer 120 after reflow. This results in weak points along the length of the sheath body 105 between the inner layer 110 and the support layer 130 and between the support layer 130 and the outer layer 120.

[0044] The reflow cycle may have multiple variables, such as peak reflow temperature, heat zone length, heat zone speed, and residence time. Exemplary peak reflow temperatures include about 150°C to about 350°C for nylon, about 220°C to about 290°C for PEBAX, and about 110°C to about 126°C for polyethylene. In certain embodiments, the peak reflow temperature used in the reflow cycle depends on the heat zone length and / or heat zone speed referenced to the sheath body 105. It should be noted that the term "about" indicates a range of ±20% of the stated value. In certain embodiments, the maximum temperature of the reflow cycle may be lower than the melting point of the material used for the rods. As such, the rods 140, 145 do not fuse to the inner layer 110, the outer layer 120, and the support layer 130 during reflow. In some embodiments, the rods 140, 145 may be removed from the sheath body 105 after reflow, thereby leaving voids 142, 146 (as shown in FIG. 2). In other embodiments, the maximum temperature of the reflow cycle may be greater than the melting point of the material used for the rods 140, 145. In some embodiments, the maximum temperature of the reflow cycle may be the same as the melting point of the material used for the rods 140, 145.

[0045] In some embodiments, the rods 140, 145 may be made from the same material type as the support layer 130. In such embodiments, the rods 140, 145 and the support layer 130 are fused together during reflow. This forms a composite support structure within the sheath body 105. This composite support structure also has points of weakness along the length of the sheath body 105 between the inner layer 110 and the composite support structure, and between the composite support structure and the outer layer 120.

[0046] For various aspects of the present disclosure, the presence of the rods 140, 145 within the reflowed sheath body 105 results in voids 142, 146 being formed along the length of the sheath body 105. As previously discussed, the voids 142, 146 extend longitudinally along the length of the rods 140, 145 when located within the sheath body 105. Thus, voids 142, 146 may form between the inner layer 110 and the support layer 130, and between the support layer 130 and the outer layer 120. Furthermore, as previously discussed, such surrounding material may be any one of the first, second, or third material types depending on the position of the rods 140, 145 prior to reflow. Thus, voids 142, 146 may form between the rods 140, 145 and the surrounding material of the sheath body 105 during reflow. Although it has been described that the rods 140, 145 may be removed from the sheath body 105 after reflow, this need not always be the case. In certain embodiments, the rods 140, 145 may remain within the sheath body 105 during use. It will be understood that even if the rods 140, 145 remain within the sheath body 105, voids 142, 146 still exist after reflow, but if the rods 140, 145 are not removed from the sheath body 105 after reflow, these voids 142, 146 are filled with the rods 140, 145. The voids 142, 146 thus serve as longitudinally extending shear lines 144, 148 within the sheath body 105 at which the sheath body 105 separates when subjected to a separation force. These shear lines 144, 148 extend longitudinally along the sheath body 105 and are positioned below the exterior surface of the sheath body 105. The gaps 142, 146 thus aid in separation of the sheath body 105 when the sheath is subjected to a separation force.

[0047] 2 shows a cross-sectional view 200 of the kink-resistant sheath 100 of FIG. 1 after layers 110, 120, 130 have been reflowed and after nylon rods 140, 145 have been removed, thereby leaving voids 142, 146 extending longitudinally along the length of the sheath body 105. As can be seen in the cross-sectional view in FIG. 2, when nylon rods 140, 145 are removed from the sheath body 105, the amount of material remaining near the voids 142, 146 is reduced compared to other sections of the sheath body 105. This thinning of the material of the sheath body 105 reduces the mechanical strength of the sheath body 105 near the voids 142, 146. Thus, when the sheath body 105 is subjected to a separation force, such as when a physician attempts to pull the sheath 100 apart, the reduced mechanical strength of the sheath body 105 along the voids 142, 146 causes the sheath 100 to tear longitudinally along the voids 142, 146. In essence, the voids 142, 146 intentionally reduce the mechanical strength of the sheath body 105 at desired locations such that tearing of the sheath body 105 is controlled and localized to occur only along the voids 142, 146. The voids 142, 146 thus serve as longitudinally extending shear lines 144, 148 within the sheath body 105 at which the sheath body 105 will separate when subjected to a separation force. In some embodiments, the voids 142, 146 may extend longitudinally along only a portion of the length of the sheath body 105.

[0048] Additionally, in certain embodiments, the voids 142, 146 may be positioned in or between at least one of the inner layer 110, the outer layer 120, and the support layer 130 based on the reflow cycle and material type discussed above. For example, the voids 142, 146 may be formed only in the inner layer 110, only in the outer layer 120, only in the support layer 130, between the inner layer 110 and the support layer 130, between the outer layer 120 and the support layer 130, or in all three layers. In any case, since the voids 142, 146 are formed inside the sheath body 105, the shear lines 144, 148 are not formed on the outer surface of the sheath body 105. Instead, the shear lines 144, 148 are formed below the outer surface and inside the sheath body 105.

[0049] Additionally, the exterior surface of the sheath body 105 may be pre-scored adjacent the gaps 142, 146. Such scores may be made with a razor blade. Although not shown in FIG. 2, the pre-scored lines form longitudinal grooves in the exterior surface of the sheath body 105 that are aligned with the shear lines 144, 148. Thus, a separation force applied to the sheath body 105 causes the sheath body to shear along the shear lines 144, 148, thereby causing longitudinal separation of the sheath body 105 along the shear lines 144, 148. Although FIGS. 1 and 2 depict a sheath with two shear lines 144, 148, it will be understood that any number of shear lines may be implemented in a sheath according to the present disclosure. Thus, when the sheath 100 is pulled apart, the sheath body 105 separates longitudinally along the shear lines 144, 148 and not elsewhere along the sheath 100. In some embodiments, the outer surface of the support layer 130 may be pre-scored; i.e., the surface of the support layer 130 that is in contact with the outer layer 120 may be pre-scored. Such scores may be made with a razor blade. The outer surface of the support layer 130 pre-scores the sheath body 105 prior to subjecting it to a reflow cycle. The scores on the outer surface of the support layer 130 aid in the separation of the sheath body 105 when the sheath 100 is pulled apart.

[0050] FIG. 3 illustrates a sheath 300 according to one embodiment of the present disclosure when subjected to a shear force that separates the sheath body. The sheath 300 has the same features as the sheath 100 in FIG. 1. As previously described, such a shear force may be applied to the sheath 300 as it is pulled apart. The sheath 300 has the same features as the sheath 100 in FIG. 1, although only one shear line 144 is illustrated in FIG. 3. Such a shear line may be formed by removable nylon rods 140, 145, similar to those in FIG. 1 and FIG. 2; in that case, voids 142, 146 are formed after the nylon rods 140, 145 are removed from the sheath body 105. Although the shear lines 144 are shown positioned on the exterior surface of the sheath body 105 in FIG. 3, it will be understood from the above description that the shear lines 144 are located within the sheath body 105 and below the exterior surface of the sheath body 105. As shown in FIG. 3, the sheath body 105 separates along the shear lines 144. Such shear lines 144 are essentially formed within the sheath body 105 by the voids 142. The reduced amount of material in the shear body 105 along the voids 142 also reduces the force required to separate or tear the sheath 300. Furthermore, because the sheath body 105 has the support structure 130 fused therein, the sheath 300 can withstand pushing forces during use (e.g., as the sheath 300 is pushed into the vasculature of a patient) without buckling or kinking.

[0051] It will be appreciated that the kink-resistant peel-away sheaths 100, 200, and 300 of Figures 1-3 as described above may be implemented as introducer sheaths for inserting a ventricular assist device into the vasculature of a patient. When used as an introducer sheath, the distal end of the sheath body 105 may be coupled to an introducer hub, such as the introducer sheath hub described in U.S. Provisional Patent Application No. 62 / 672,212 and the introducer hub described in U.S. Patent Application No. 15 / 438,171, the entire contents of which are incorporated herein by reference. Such introducer hubs are configured with notches and wings that allow the hub to easily split into at least two sections upon application of a small amount of force. When such a hub is coupled to a kink-resistant peel-away sheath of the present disclosure, separation of the sheath body 105 along the shear lines 144, 148 occurs when the hub splits, thereby allowing a physician to perform controlled separation of the sheath body 105.

[0052] 4 shows a sheath 400 according to a further embodiment of the present disclosure. The sheath 400 includes a sheath body 405 having a structure similar to that of the sheath body 105; that is, the sheath body 405 includes an inner layer 410, an outer layer 420 arranged coaxially around the inner layer 410, a support layer 430 positioned between the inner layer 410 and the outer layer 420, and a nylon rod. As with the sheath 100, the nylon rod may be positioned within the sheath 400 between the outer layer 420 and the support layer 430 or between the inner layer 410 and the support layer 430. However, unlike the sheath 100 of FIG. 1, where the rods 140, 145 extend linearly along the longitudinal axis of the sheath body 105, in the sheath 400 the rods extend helically around the longitudinal axis of the sheath body 405. In this configuration, the nylon rod effectively forms a double helix extending longitudinally around the sheath body 405. In doing so, the helically wrapped nylon rod provides additional strength and stiffness to the sheath 400, which is beneficial when inserting the sheath 400 into the patient's vasculature. This ensures that the sheath 400 does not kink during insertion into the patient. After the layered sheath body 405 and nylon rod are reflowed, voids 442, 446 are formed along the length of the sheath body 105. In some embodiments, the nylon rod may be removed from the sheath body 405 to leave in place of the nylon rod voids 442, 446 extending longitudinally along the sheath body 405 in a double helix fashion. As noted with respect to FIG. 1, each of the voids 442, 446 forms a helical shear line 444, 448 extending longitudinally along the sheath body 405. 1 and 2, and sheath 300 in FIG. 3, the shear lines 444 are located within the sheath body 405 and below the exterior surface of the sheath body 405. It will be understood that the helical rod disclosed with respect to the sheath 400 in FIG. 4 is not the same as the support layer comprising a coil or laser cut spirals disclosed above with respect to the sheath 100 in FIG.

[0053] To separate the sheath body 405, instead of applying a separation force to either side of the sheath body (as with sheath 100), the physician simply unrolls the distal end of the sheath body 405 to tear the sheath 405 apart. With shear lines forming intertwining helices in the structure, the sheath body 405 tears like ribbons when subjected to a shear force, as depicted in FIG.

[0054] 5A-5B show a sheath 500 according to a further embodiment of the present disclosure. The sheath 500 comprises a sheath body 505 comprising an inner layer 510, an outer layer 520 arranged coaxially around the inner layer 510, and a support layer 530 positioned between the inner layer 510 and the outer layer 520. FIG. 5A shows a detailed configuration of the support layer 530 according to one embodiment of the present disclosure. Unlike the sheath 100 shown in FIG. 1, in which the support layer 130 comprises a tubular braided structure, the support layer 530 comprises interwoven S-wires 532, 534. The S-wires 532, 534 are additionally interlocked with mandrels 540, 545. In this configuration, the S-wires 532 alternately wrap around and around the mandrels 540, 545 in a zigzag pattern across the upper half of the outer surface of the inner layer 510. Similarly, the S-wire 534 alternately wraps around and around the mandrels 540, 545 in a zigzag fashion across the lower half of the outer surface of the inner layer 510. Additionally, the S-wires 532, 534 and the mandrels 540, 545 are arranged such that the S-wires 532, 534 interweave with each other around each mandrel 540, 545. Thus, as shown in FIG. 5A, the S-wires 532, 534 are arranged alternately above and below the mandrels while moving longitudinally along each mandrel 540, 545. In this manner, the mandrels 540, 545 lock the S-wires 532, 534 in place around the inner layer 510. Although only two S-wires and two mandrels are shown in FIG. 5A, embodiments with any number of S-wires and mandrels are also within the scope of the present disclosure.

[0055] Similar to the previously described sheaths, the inner layer 510, outer layer 520, and support layer 530 of the sheath 500 are reflowed so that the layers are fused together. The interwoven S-wires 532, 534 within the fused layers of the sheath body 505 increase the flexibility and pushability of the sheath 500 while preventing the formation of kinks when the sheath is inserted into the patient's vasculature. After the reflow process, the mandrels 540, 545 are withdrawn in a manner similar to the nylon rods previously described. Such withdrawal of the mandrels 540, 545 is depicted in FIG. 5B, leaving voids 542, 546 within the sheath body 505. The voids 542, 546 extend longitudinally along the sheath body 505 and define shear lines within the sheath body 505. For example, void 542 defines a shear line on one side of sheath body 505 (not shown), while void 546 defines another shear line 565 on the opposite side of sheath body 505. In the embodiment shown in Figures 5A-5B, the shear line is generally sinusoidal due to the position of the peaks and troughs in S-wires 532, 534 embedded within sheath body 505 relative to voids 542, 546. Although the shear lines in Figures 5A-5B are described as being generally sinusoidal, it will be understood that the shear lines may take any shape and configuration. Similar to sheaths 100, 300, and 400 described in previous embodiments, the shear lines in Figure 5B are located within the sheath body 505 and below the exterior surface of the sheath body 505. When the sheath 500 is subjected to a separation force, such as when the sheath 500 is pulled apart by a physician, the sheath body 505 separates into a first portion 550 and a second portion 560. As with the sheaths previously described, the sheath lines define the manner in which the sheath separates when subjected to a separation force. Thus, the shear lines aid in the separation of the sheath body 505 into the first portion 550 and the second portion 560 when the sheath 500 is pulled apart.

[0056] FIG. 6 illustrates a cross-sectional view of a sheath 600 according to a further embodiment of the present disclosure. The sheath 600 has a longitudinal axis that extends into or out of the page. Unlike previously described sheaths, the sheath 600 does not utilize longitudinal voids to create shear lines within the sheath body. The sheath 600 includes an inner layer 610, an outer layer 620 arranged coaxially around the inner layer 610, and a support layer 630 positioned between the inner layer 610 and the outer layer 630. The support layer 630 may be configured in any manner as previously described with respect to FIGS. 1-4 and 5A-5B. In the embodiment of FIG. 6, the inner layer 610, the outer layer 620, and the support layer 630 are subjected to a first reflow process that fuses the respective layers together to form the sheath body 605.

[0057] The sheath body 605 is then split along its longitudinal axis into a first portion 650 and a second portion 660. The sheath body 605 may be split, for example, by laser cutting. The first portion 650 and the second portion 660 are then physically reassembled. The physically reassembled sheath body 605 is then subjected to a second reflow process. The second reflow process may be different from the first reflow process. For example, the temperature profile used may have a lower peak temperature or the peak temperature used may be applied for a shorter period of time. This second reflow process causes the first portion 650 and the second portion 660 to fuse together along the edges where the sheath body 605 was split. This results in the formation of frangible seams 670, 675 along the length of the sheath body 605. The temperature profile of the second reflow process is selected such that when the first portion 650 and the second portion 660 are fused together, as shown in FIG. 6, the frangible seams 670, 675 are located inside the sheath body 605, such that the seams 670, 675 do not extend to the outer surface of the sheath body 605.

[0058] The seams 670, 675 are easily broken upon application of a separation force. Thus, the reassembled sheath body 605 is easily separated at the first portion 650 and the second portion 660 when subjected to a separation force, such as when the sheath 600 is pulled apart by the physician. The seams 670, 675 thus define a shear line along the sheath body 605 at which the sheath separates. As with the sheaths previously described, the shear line defines the manner in which the sheath 600 separates when subjected to a separation force. The fused inner layer 610, outer layer 620, and support layer 630 of the sheath body 605 enhance the flexibility and pushability of the sheath 600 while preventing the formation of kinks in the sheath body 605. Additionally, the frangible seams 670, 675 allow the sheath body 605 to be easily separated or torn apart. Additionally, the frangible seams 670 , 675 are located within the sheath body 605 such that the seams 670 , 675 do not extend to the exterior surface of the sheath body 605 , so that the shear lines of the sheath 600 are located within the sheath body 605 and below the exterior surface of the sheath body 605 .

[0059] FIG. 7 illustrates a cross-sectional view of a sheath 700 according to a further embodiment of the present disclosure. The sheath 700 has a longitudinal axis that extends into or out of the page. Similar to the sheath 600 in FIG. 6, the sheath 700 does not utilize a longitudinal gap to create shear lines within the sheath body. The sheath 700 includes an inner layer 710 having a lumen 715 running therethrough, an outer layer 720 arranged coaxially around the inner layer 710, and a support layer 730 positioned between the inner layer 710 and the outer layer 730. The support layer 730 may be configured in any manner as described above with respect to FIGS. 1-4 and 5A-5B. In the embodiment of FIG. 7, the inner layer 710, the outer layer 720, and the support layer 730 are subjected to a first reflow process that fuses the respective layers together to form the sheath body 705.

[0060] The sheath body 705 is then split along the longitudinal axis into a first portion 750 and a second portion 760. The sheath body 705 may be split, for example, by laser cutting. The first portion 750 and the second portion 760 are then arranged around an extruded layer 770 having a lumen therethrough. The lumen of the extruded layer 770 is concentric with the lumen 715 and has a smaller diameter than the lumen 715. The extruded layer 770 is dimensioned such that when the first portion 750 and the second portion 760 are arranged around the extruded layer 770, the split edges of the first and second portions do not meet, thereby leaving gaps 755, 765 extending longitudinally along the sheath body 705. The assembly is then subjected to a second reflow process. The second reflow process may differ from the first reflow process. For example, the temperature profile used may have a lower peak temperature or the peak temperature used may be applied for a shorter period of time. This second reflow process fuses the extruded layer 770 to the inner surfaces of the first and second portions 750, 760 of the split sheath body 705. This results in the formation of frangible connections 780, 785 in the gaps 755, 765 that extend along the length of the sheath body 705, as shown in Figure 7. The temperature profile of the second reflow process is selected such that when the first and second portions 750, 760 are fused together, the connections 780, 785 in the gaps 755, 765 are located inside the sheath body 705, such that the connections 780, 785 do not extend to the outer surface of the sheath body 705, as shown in Figure 7.

[0061] Extruded layer 770 may have any thickness. Preferably, extruded layer 770 is thinner than inner layer 710 and outer layer 720. In some embodiments, extruded layer 770 may comprise any one of a polyether block amide (such as PEBAX or PebaSlix®), a polyethylene material, a polytetrafluoroethylene (PTFE) material, a high density polyethylene (HDPE) material, a medium density polyethylene (MDPE) material, and a low density polyethylene (LDPE) material.

[0062] The connections 780, 785 are easily broken upon application of a separation force to the first portion 750 and the second portion 760 of the sheath body 705, such as when the sheath 700 is pulled apart by a physician. The connections 780, 785 thus define a shear line along the sheath body 705 at which the sheath 700 separates. In the case of the sheath 700, the shear line coincides with the gaps 755, 765 in the sheath body 705. As with the previously described sheaths, the shear line defines the manner in which the sheath 700 separates when subjected to a separation force. The fused inner layer 710, outer layer 720, and support layer 730 of the sheath body 705 enhance the flexibility and pushability of the sheath 700 while preventing the formation of kinks in the sheath body 705. The frangible connections 780, 785 allow the sheath body 705 to be easily separated or torn apart. Additionally, the frangible connections 780 , 785 are located within the sheath body 705 such that they do not extend to the outer surface of the sheath body 705 , so that the shear line of the sheath 700 is located within the sheath body 705 and below the outer surface of the sheath body 705 .

[0063] A method of making a kink resistant peel away sheath, such as the sheaths described above, will now be described with reference to method 800 of FIG. 8. The method begins at step 810 where an inner layer is provided. Here, the inner layer comprises an open tubular layer having a lumen running therethrough. The inner layer may comprise a first material. Next, a support layer is arranged coaxially with the inner layer, per step 820. The support layer may be tubular with a circular cross section. The support layer may comprise a third material. The support layer may comprise a braided structure that strengthens the inner layer, such as support layer 130 shown in FIG. 1. Alternatively, the support layer may comprise a tubular coil, as shown in FIGS. 5A-5B, or at least one S-wire wrapped around the outer surface of the inner layer, releasably interlocked with a corresponding number of mandrels. Additionally, the support layer may comprise a laser cut extrusion, cut according to any pattern that enhances the pushability of the sheath while maintaining its flexibility.

[0064] In addition to the support layer, monofilaments or rods, such as nylon rods 140, 145, 440, 445 described with respect to Figures 1-4, may be positioned radially on the outer surface of the support layer. Any number of rods may be used in the layered structure. Preferably, two rods may be used, radially spaced 180° apart from each other about the long axis of the sheath. The rods may extend linearly along the long axis of the sheath. In other configurations, the rods may form a helix on the outer surface of the support layer.

[0065] In step 830, an outer layer is coaxially arranged on the inner layer and the support layer to provide a layered structure such as that shown in FIG. 1. Optionally, if rods are used, the outer layer is arranged to include the inner layer, the support layer, and the rods as shown in FIG. 1. The outer layer may comprise a second material. In some embodiments, the thickness of the inner layer may be equal to the thickness of the outer layer. In other embodiments, the inner and outer layers may have different thicknesses to control the stiffness and flexibility of the sheath. Additionally, in some embodiments, the support layer may be thinner than the inner and outer layers. In step 840, the layered structure is subjected to a reflow cycle in which the layered structure is exposed to heat based on a temperature profile. The heat treatment causes the inner, outer, and support layers to laminate together to form the sheath body as a single fused layer. The lamination of the layers increases the flexibility and pushability of the sheath while preventing the formation of kinks in the sheath body. In certain embodiments, the maximum temperature of the reflow cycle is below the melting point of nylon. Thus, in embodiments where the nylon rod is inserted adjacent the outer surface of the support layer (step 820), the rod does not fuse to the other remaining layers, thereby allowing it to be removed from the sheath body after the reflow process, leaving in its place a void, such as voids 142, 146 in Figure 2. In some embodiments, the rod does not need to be removed from the laminated structure of the sheath body.

[0066] At step 850, shear lines are formed in the sheath body. The shear lines comprise lines or voids formed in the sheath body where a small force is required to separate the sheath bodies. Such shear lines may be formed in areas where the thickness of the sheath body has been reduced, such as by pre-scoring the outer surface of the sheath body with a razor blade. For embodiments utilizing nylon rods during reflow, the sheath body reduces in thickness in the area of ​​the nylon rod. Thus, when the rod is removed, a void remains in that location in the sheath body. The formation of such voids results in a thinning of the sheath body in the area immediately adjacent the void, thereby forming the shear lines. In such embodiments, when a separation force is applied to the sheath body, it naturally tears or tears the sheath body at these thinned areas.

[0067] In some embodiments, the first material used for the inner layer may comprise any one of polyether block amide (such as PEBAX or PebaSlix®), polyethylene material, polytetrafluoroethylene (PTFE) material, high density polyethylene (HDPE) material, medium density polyethylene (MDPE) material, and low density polyethylene (LDPE) material. In some embodiments, the second material used for the outer layer may comprise the first material; that is, the inner layer and the outer layer may be made of the same material. Furthermore, in certain embodiments, the third material used for the support layer may comprise any one of polyetheretherketone (PEEK), polyether block amide (such as PEBAX or PebaSlix®), polyethylene material, polytetrafluoroethylene (PTFE) material, nylon, high density polyethylene (HDPE) material, medium density polyethylene (MDPE) material, and low density polyethylene (LDPE) material.

[0068] FIG. 9 illustrates an exemplary method 900 of using a kink-resistant peel-away sheath, such as any of the sheaths previously described, according to one embodiment of the present disclosure. The method 900 begins at step 910, where the kink-resistant peel-away sheath is inserted into a patient's arteriotomy, such as the femoral artery. As previously described, any of the previously described sheaths may have a tip formed on the end of the sheath body proximal to the patient. Such a tip may be beveled to aid in insertion into the patient. The laminated construction of the sheath body allows the sheath to withstand large pushing forces, such as those used to insert the sheath into the patient, without kinking, bending, or buckling. In certain embodiments, a dilator may be inserted into the lumen of the sheath prior to insertion into the patient. The dilator aids in positioning the sheath in areas of the patient's body that are difficult to penetrate with the sheath alone. Once inserted, the dilator is removed from the lumen of the sheath.

[0069] In step 920, the inserted sheath is removed to insert the medical device into the patient. As previously described, such a medical device may be a cardiac pump with a narrow diameter catheter body and a larger diameter pump head. To insert the pump head into the patient's arteriotomy, the sheath needs to be removed or torn apart. To tear the sheath, a separation force is applied to either side of the distal end of the sheath body to pull the sheath body apart. Such a separation force may be applied by a physician. As previously described, the sheath body contains shear lines that run along the longitudinal length of the sheath body and are located below the outer surface of the sheath body. Such shear lines are weak points in the sheath body structure. Thus, when the distal end of the sheath body is subjected to a separation force, the sheath body easily separates or tears apart. Once the sheath body is torn apart, the larger diameter portion of the medical device, such as the pump head, can be advanced into the patient's arteriotomy for use, as shown in step 930 of FIG. 9. The use of a peel-away sheath in accordance with aspects of the present disclosure allows for greater pushing forces to be applied to the sheath during positioning without kinking, bending, or buckling of the sheath, while ensuring that the sheath is easily torn apart during a medical procedure.

[0070] If desired, the different steps discussed herein may be performed in different orders and / or simultaneously with one another. Furthermore, if desired, one or more of the above-mentioned steps may be optional or may be combined.

[0071] The foregoing is merely illustrative of the principles of the present disclosure, and the devices and methods of the present invention may be practiced other than in the described embodiments, which are presented for purposes of illustration and not limitation. It should be understood that the devices and methods disclosed herein, although illustrated for use in the manufacture of kink-resistant peel-away sheaths, may also be applied to other systems in which a rigid, yet flexible, open passage into the patient's vasculature is required during an intravascular procedure.

[0072] After reading this disclosure, those skilled in the art will have variations and modifications. The features of the present disclosure may be implemented in any combination and subcombination (including multiple subordinate combinations and subcombinations) with one or more other features described herein. The various features described or illustrated above, including their components, may be combined or integrated into other systems. Furthermore, certain features may be omitted or not implemented.

[0073] Examples of changes, substitutions, and alterations are ascertainable by one of ordinary skill in the art and can be made without departing from the scope of the information disclosed herein. All references cited herein are incorporated by reference in their entirety and made a part of this application.

Claims

1. 1. A method of making a kink resistant peel away sheath, comprising: providing a sheath body comprising a tubular inner layer having a longitudinal axis and a lumen formed therethrough, an outer layer arranged coaxially with the inner layer, and a support layer disposed between the inner and outer layers; splitting the sheath body along a line parallel to the longitudinal axis; reassembling the split sheath body; reflowing the reassembled sheath body to form at least one weakened seam reconnecting the sheath body, the at least one weakened seam configured to allow the sheath body to be longitudinally separated along the weakened seam.

2. The method of claim 1 , wherein the step of providing a sheath body includes the step of reflowing the inner layer, the outer layer, and the support layer to fuse the inner layer, the outer layer, and the support layer together.

3. The method of claim 1 or claim 2, wherein the at least one weak joint is a weak seam.

4. 4. The method of claim 3, wherein the step of reflowing the reassembled sheath body uses a temperature profile selected such that the weak seam is located within the sheath body and does not extend to an exterior surface.

5. The method of any one of claims 1 to 4, further comprising the step of arranging the support layer coaxially between the inner and outer layers.

6. the splitting step includes splitting the sheath body into a first portion and a second portion along a line parallel to the longitudinal axis; The method of any one of claims 1 to 5, wherein the reassembling step comprises reassembling the first and second parts.

7. The method of claim 6 , wherein the reflow process forms a first weakened seam and a second weakened seam along the reconnected edges of the first and second portions.

8. The method of any one of claims 1 to 7, wherein the inner and outer layers comprise extrusions.

9. The method according to any one of claims 1 to 8, wherein the inner and outer layers are made from any one of the following materials: Polyether block amides (such as PEBAX or PebaSlix®), polyethylene materials, polytetrafluoroethylene (PTFE) materials, high density polyethylene (HDPE) materials, medium density polyethylene (MDPE) materials, and low density polyethylene (LDPE) materials.

10. The method of any one of claims 1 to 9, wherein the support layer comprises a braid or a coil.

11. The method of any one of claims 1 to 9, wherein the support layer comprises a spirally wound laser cut layer.

12. 12. The method of claim 1, wherein the step of providing a support layer laminated between the inner layer and the outer layer further comprises interlocking a plurality of S-shaped wires wound around the inner layer with a corresponding number of removable mandrels, each mandrel being removable to form a shear line in the sheath body.

13. The method according to any one of claims 1 to 12, wherein the support layer is made from any one of the following materials: Polyetheretherketone (PEEK), Polyether block amide (such as PEBAX or PebaSlix®), Polyethylene materials, Polytetrafluoroethylene (PTFE) materials, Nylon, High Density Polyethylene (HDPE) materials, Medium Density Polyethylene (MDPE) materials, Low Density Polyethylene (LDPE) materials, Stainless Steel.

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