Patterned tie layers for optimized catheter performance

Abstract

The intravascular catheter comprises a hypotube structure having an elongated tubular body having a proximal end, a distal end, a hypotube pattern of openings and solid elements disposed at the distal end of the tubular body, and a hypotube lumen extending between the proximal and distal ends of the tubular body. The intravascular catheter further comprises an inner polymeric liner disposed within the hypotube lumen, the inner polymeric liner having a liner lumen. The intravascular catheter further comprises a tie layer intermittently attaching the inner polymeric liner to the solid elements of the hypotube structure at at least one discrete bonded area along the length of the distal end of the tubular body.

Description

[Technical field]

[0001] The present disclosure relates generally to medical devices, and more particularly to medical catheters. [Background technology]

[0002] It is well known to use intravascular catheters to access and treat various types of diseases, such as vascular defects. For example, a suitable intravascular catheter can be inserted into the vascular system of a patient. A commonly used vascular application to access a target site in a patient involves inserting a guidewire through an incision in the femoral artery near the groin and advancing the guidewire until the target site is reached. A catheter is then advanced over the guidewire through a lumen within the catheter until the open distal end of the catheter is positioned at the target site. Concurrently with or after the distal end of the catheter is positioned at the target site, an intravascular implant is advanced through the lumen of the catheter via a delivery wire.

[0003] In certain applications, such as neurovascular therapy, catheters must pass through tortuous and complex vasculature. By using appropriately sized devices with the required performance characteristics such as "pushability," "steering ability," "torqueability," and most importantly, distal tip flexibility, virtually any target site within the vasculature can be accessed, including within the tortuous cerebral and peripheral vasculature. The force applied at the proximal end of those catheters needs to be adequately transferred to the distal end to achieve pushability (axial stiffness) and torqueability (rotation). Achieving a balance between those functions is highly desirable but difficult.

[0004] In such neurovascular therapeutic applications, as well as other applications involving the passage of various other devices, agents and / or fluids through a catheter into a patient's body cavities or spaces, the properties of the inner surface of the catheter's lumen or lumens can significantly affect the performance of the catheter. In particular, the lubricity of the inner surface can affect the ability to pass other devices, agents and / or fluids through the catheter's lumen or lumens.

[0005] To enhance lubricity, a low-friction liner (e.g., polytetrafluoroethylene (PTFE), expanded PTFE (ePTFE, e.g., unidirectional ePTFE or bidirectional ePTFE), fluoropolymer, perfluoroalkoxy, alkanes (PFA), fluorinated ethylene polyethylene (FEP), polyethylene (PE), or any combination thereof) can surround the lumen of the catheter. The liner can provide a smooth inner surface to facilitate threading of a guidewire, pacing lead, or other device through the lumen of the catheter. However, construction of such catheters is complicated by the difficulty of bonding the low-friction liner to the outer jacket of the catheter. For example, PTFE in its native form is nearly impossible to bond. Improper assembly of the liner into the catheter can result in delamination. This is a challenging failure mode in catheter construction that carries both risk and cost burden for many device manufacturers. It is usually discovered during final testing after manufacturing of the finished catheter assembly, resulting in a significant decrease in the yield of the final product. More importantly, delamination can lead to field failures and product recalls.

[0006] To prevent delamination between the inner liner and the outer jacket of the catheter, a tie layer in the form of a very thin thermoplastic coating may be added onto the inner polymer liner during construction of the catheter. This tie layer forms a melt-bondable substrate and improves adhesion to both the inner polymer liner and the outer jacket of the catheter. Alternatively, other forms of adhesives such as liquids, dispersions, or solids may be used.

[0007] There are currently many microcatheter designs that utilize hypotubes in their construction. Generally, hypotubes are long, thin-walled tubes formed from metals or metal alloys such as stainless steel, nickel-titanium alloys (e.g., Nitinol), hard plastics, and the like. Hypotubes often have micromachined features along their length. The distal end of the hypotube may have a slot pattern that enhances its flexibility while providing sufficient axial stiffness to maintain the pushability of the hypotube through the patient's vasculature. As mentioned above, it may be desirable to incorporate some type of inner liner into the slotted hypotube to provide a low friction interface with the device being pushed through the hypotube. Such a liner may be slightly undersized during manufacture to slide within the slotted hypotube. In other embodiments, the slotted tube may have reinforcements that provide more support and integrity to the liner as the catheter travels through the vasculature to reach the treatment site. In some cases, a polymer jacket may be added to the outer diameter of the slotted hypotube to provide a seal and minimize the external roughness of the hypotube slots while still allowing flexibility. This outer jacket may also seal the openings / slots in the hypotube and coat the inner surface of the hypotube.

[0008] However, it has been found that even the thinnest PTFE liners can add unacceptable stiffness to the distal end of a slotted hypotube catheter. In particular, the slotted hypotube structure 1, which includes a pattern of openings (e.g., slots) 2 and solid elements (e.g., struts) 4 shown in FIG. 1, requires that the openings 2 of the hypotube structure 1 be free to open and close in response to bending forces in order to provide flexibility. If the inner polymer liner 4 is intimately and continuously bonded to the inner surface of the solid elements 3 of the hypotube structure 1 via a tie layer 5, the inner polymer liner 4 must stretch in order to open the openings 2. This can require a relatively high rate of stretch since only the polymer spanning the openings 2 can stretch. In the distal region of the slotted hypotube catheter, the inner polymer liner is by far the dominant element in terms of stiffness.

[0009] The close / continuous bond between the inner liner and the hypotube structure not only adversely affects the flexibility of the distal region of the slotted hypotube catheter, but past experience has shown that it also adversely affects the torqueability and maneuverability of the catheter structure. In particular, the relatively large strains required to bend the distal region of the slotted hypotube catheter can lead to plastic deformation of the inner polymer liner, which can cause permanent bending in the distal region of the catheter. Application of torque to a deformed catheter can result in violent movement of the distal end of the catheter, adversely affecting the steerability of the catheter.

[0010] One approach to address this issue is to provide a "floating" inner polymer liner that is bonded to the slotted hypotube structure at discrete locations to prevent the liner from bunching or moving independently of the slotted hypotube structure. However, such floating liners must be constructed of composite materials reinforced with metal coils or braids to prevent collapse under vacuum, and must be loosely toleranced to fit properly within the hypotube structure (so that the liner can slide into the hypotube structure), both of which lead to increased wall thickness. Furthermore, in order for the inner polymer liner to "float" within the slotted hypotube structure (i.e., there is space between the slotted hypotube structure and the inner polymer liner between the bonded discrete locations), the outer diameter of the catheter must be increased to maintain patency of the operating lumen within the catheter. This floating liner must be laboriously bonded to the hypotube structure at discrete locations through the slots in the hypotube structure, resulting in time-consuming manufacture.

[0011] Thus, there is a continuing need for an efficient manner of bonding an inner polymer lining to a slotted hypotube structure without unduly increasing the bending stiffness of the slotted hypotube structure. [Brief description of the drawings]

[0012] The drawings illustrate the design and utility of preferred embodiments of the disclosed invention, with similar elements being commonly labeled. It should be noted that the drawings are not drawn to scale, and that elements of similar structure or function are designated by similar reference numerals throughout the drawings. It should also be noted that the drawings are intended only to facilitate the description of the embodiments. They are not intended as an exhaustive description of the invention, nor are they intended to limit the scope of the invention, which is defined only by the appended claims and their equivalents. Furthermore, an exemplary embodiment of the disclosed invention need not have all of the disclosed aspects or advantages. Moreover, an aspect or advantage described in connection with a particular embodiment of the disclosed invention is not necessarily limited to that embodiment, and may be implemented in any other embodiment, even if not so illustrated.

[0013] In order to better understand how the above-mentioned and other advantages and objects of the disclosed invention are obtained, a more particular description of the disclosed invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the accompanying drawings, the invention will be described and explained with additional specificity and detail using the accompanying drawings, with the understanding that these drawings depict only typical embodiments of the invention and are therefore not to be considered as limiting its scope.

[0014] [Figure 1] FIG. 1 is a longitudinal cross-sectional view of a prior art slotted hypotube structure. [Diagram 2] FIG. 2 is a side view of one embodiment of an intravascular catheter, particularly showing the distal end of the intravascular catheter in a straight configuration. [Diagram 3] FIG. 3 is a side view of the intravascular catheter of FIG. 2, particularly showing the distal end of the intravascular catheter in a curved configuration. [Figure 4] 4 is a side view of the distal end of one embodiment of a hypotube structure used in the intravascular catheter of FIG. [Diagram 5]FIG. 5 is a perspective view of the distal end of the hypotube structure of FIG. [Figure 6] 6 is a cross-sectional view of the distal end of one embodiment of the catheter body of the intravascular catheter of FIG. 2. [Figure 7] FIG. 7 is a longitudinal cross-sectional view of the distal end of the catheter body of FIG. 6, particularly showing one embodiment of the tie layer. [Figure 8] FIG. 8 is a perspective view of the distal end of another embodiment of a hypotube structure used in the catheter body of FIG. [Figure 9] FIG. 9 is a perspective view of one embodiment of an inner polymer liner used in the catheter body of FIG. [Figure 10] FIG. 10 is a longitudinal cross-sectional view of the distal end of the catheter body of FIG. 6, particularly showing another embodiment of the tie layer. [Figure 11] FIG. 11 is a longitudinal cross-sectional view of the distal end of the catheter body of FIG. 6, particularly showing yet another embodiment of a tie layer. [Figure 12] FIG. 12 is a side view of the inner polymer liner of FIG. 9, particularly showing one embodiment of the discrete bonded regions. [Figure 13] FIG. 13 is a side view of the inner polymer liner of FIG. 9, particularly showing another embodiment of the discrete bonded regions. [Figure 14] FIG. 14 is a longitudinal cross-sectional view of the distal end of the catheter body of FIG. 6, particularly showing yet another embodiment of a tie layer. [Figure 15] 15 is a cross-sectional view of the distal end of another embodiment of the catheter body of FIG. [Figure 16] 16A-16C are longitudinal cross-sectional views of the distal end of the catheter body of FIG. 15, particularly illustrating several embodiments of the tie layer. [Figure 17] FIG. 17 is a flow diagram illustrating one method of manufacturing the intravascular catheter of FIG. [Figure 18] FIG. 18 is a perspective view of one tubular body used to manufacture the hypotube structure according to the flow diagram of FIG. [Figure 19] FIG. 19 is a perspective view of the pattern of openings and solid elements formed in the distal end of the tubular body of FIG. 18 to produce a hypotube structure. [Figure 20] FIG. 20 is a perspective view of one polymer tube. [Figure 21] 21 is a perspective view of the polymer tube of FIG. 20 positioned within the inner lumen of the hypotube structure of FIG. 19 according to the flow diagram of FIG. [Figure 22] FIG. 22 is a perspective view of a polymer tube intermittently bonded to a hypotube structure via a plurality of discrete bond areas according to the flow diagram of FIG. [Figure 23] FIG. 23 is a perspective view showing one approach for providing a tie layer to the polymer tube of FIG. [Figure 24] FIG. 24 is a perspective view showing an alternative approach to providing a continuous tie layer to the polymer tube of FIG. [Diagram 25] FIG. 25 is a perspective view showing a technique for providing an adhesive pattern on the continuous bonding layer of FIG. [Figure 26] FIG. 26 is a perspective view illustrating an approach for forming a pattern of adhesive material on the continuous bonding layer of FIG. [Figure 27] FIG. 27 is a perspective view illustrating an alternative approach to forming a pattern of adhesive material on the continuous bonding layer of FIG. [Figure 28] FIG. 28 is a longitudinal cross-sectional view of the distal end of the intravascular catheter of FIG. 2, specifically illustrating an alternative approach to providing a tie layer to the polymeric tube of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] 2 and 3, an embodiment of an intravascular catheter 10 is described. The intravascular catheter 10 has a tubular configuration and may take the form of, for example, a microcatheter, a sheath, or the like. In the illustrated embodiment, the intravascular catheter 10 functions as a delivery catheter for delivering the vascular occlusion device 12 into the aneurysm, however, alternative embodiments of the intravascular catheter 10 may deliver other medical devices, for example, another catheter, a guide member, a stent, a thrombus removal device, or the like. Additionally, other alternative embodiments of the intravascular catheter 10 may function as an operating catheter, for example, a therapeutic catheter or a diagnostic catheter. The pusher member 14 is removably coupled to the vascular occlusion device 12 via a joint 16 (e.g., mechanical, thermal, and hydraulic mechanisms). Thus, the pusher member 14 may be advanced distally to deploy the vascular occlusion device 12 from the intravascular catheter 10 into the aneurysm (not shown) and selectively detached from the pusher member 14 by the action of the joint 16 to deliver the vascular occlusion device 12 into the aneurysm.

[0016] The intravascular catheter 10 generally comprises an elongated catheter body 18 that is topologically divided between a proximal catheter body section 20 and a distal catheter body section 22, an inner catheter lumen 24 extending within the catheter body 18 from the proximal catheter body section 20 to the distal catheter body section 22, and a proximal catheter hub 26 attached to the proximal catheter body section 20.

[0017] The proximal catheter body section 20 remains outside the patient and is accessible to the operator, while the distal catheter body section 22 is sized and dimensioned to reach remote locations in the patient's vasculature and is configured to deliver the vascular occlusion device 12 to an aneurysm (not shown). The distal catheter body section 22 is more flexible than the proximal catheter body section 20 and can transition between a straight shape (FIG. 2) and a curved shape (FIG. 3). Typically, the proximal catheter body section 20 is formed from a stiffer material than the distal catheter body section 22, such that the proximal catheter body section 20 has sufficient pushability to advance through the patient's vasculature, while the distal catheter body section 22 is formed from a more flexible material so that the distal catheter body section 22 remains flexible and can more easily track over a guidewire to access remote locations in tortuous areas of the vasculature. In some cases, the proximal catheter body section 20 may include a reinforcing layer, such as a braided or coiled layer, to enhance the pushability of the catheter body 18. The catheter body 18 may optionally include an intermediate catheter body section (not shown) that gradually transitions from the relatively high bending stiffness of the proximal catheter body section 20 to the relatively low bending stiffness of the distal catheter body section 22. The distal tip 28 of the distal catheter body section 22 may be rounded to minimize the possibility of traumatic puncture of body tissue. The intravascular catheter 12 includes a distal port 30 at the distal tip 28 that communicates with the inner catheter lumen 24, from which the vascular occlusion device 16 is deployed.

[0018] The catheter body 18 has a length suitable for accessing a target tissue site within a patient from a vascular access point. The target tissue site depends on the medical procedure for which the intravascular catheter 10 is used. For example, if the intravascular catheter 10 is used to access the vasculature in the patient's brain from a femoral artery access point in the patient's groin, the overall length of the catheter body 18 may be 125 cm to 200 cm. In one embodiment, the outer diameter of the catheter body 18 may be uniform along the length of the catheter body 18. In another embodiment, the outer diameter of the catheter body 18 may taper gradually or in steps from a first outer diameter of the proximal catheter body section 20 to a second outer diameter of the distal catheter body section 22.

[0019] The outer diameter of the catheter body 18 may range from 3F to 10F. The outer diameter of the distal catheter body section 22 may be smaller than the outer diameter of the proximal catheter body section 20, thereby allowing the distal catheter body section 22 to have a smaller profile and facilitate navigation within a tortuous vasculature. Although depicted as having a generally circular cross-sectional shape in the drawings, it should be understood that the intravascular catheter 10 may include other cross-sectional shapes or combinations of shapes, such as oval, rectangular, triangular, polygonal, etc. The catheter body 18 is structurally configured to be relatively flexible, easy to push, and relatively resistant to kinking and buckling, and is capable of resisting buckling when a pushing force is applied to the proximal catheter body section 20 to advance the catheter body 18 distally through the patient's vasculature, and is capable of resisting kinking when traversing sharp turns within the vasculature. The catheter body 18 may be relatively thin-walled so as to define a relatively large inner diameter for a given outer diameter, which may further contribute to the flexibility and kink resistance of the catheter body 18.

[0020] In some embodiments, at least a portion of the outer surface of the catheter body 18 can include one or more coatings, such as an anti-thrombogenic coating, an anti-bacterial coating, or a lubricious coating (e.g., a hydrophilic coating) that helps reduce thrombus formation in vitro and can reduce static or kinetic friction between the catheter body 18 and the patient's tissue, for example, as the catheter body 18 is advanced through the vasculature or another catheter.

[0021] The diameter of the inner catheter lumen 24 can vary based on the medical procedure for which the intravascular catheter 10 is used, and in the illustrated embodiment is sized to accommodate the vascular occlusion device 16. The diameter of the inner catheter lumen 24 may be substantially constant from the proximal catheter body section 20 to the distal catheter body section 22, or it may taper from a first diameter at the proximal catheter body section 20 to a second, different diameter at the distal catheter body section 22.

[0022] The proximal catheter hub 26 can be joined to the proximal catheter body section 20 using suitable means, such as, for example, adhesives, welding, etc. The proximal catheter hub 26 includes a proximal port 32 through which the inner catheter lumen 24 can be accessed and can be closed in some embodiments. For example, the proximal port 32 can be located at the proximal end of the proximal catheter hub 26 and aligned with the inner catheter lumen 24, thereby allowing access to the inner catheter lumen 24 through the proximal port 34. The vascular occlusion device 12 having the pusher member 14 can then be introduced into the inner catheter lumen 24 through the proximal port 34 of the catheter hub 26. The proximal catheter hub 26 can further include a side port 36 in fluid communication with the inner catheter lumen 24 and can be used to introduce fluid into the catheter body 18. In some embodiments, in addition to or instead of the proximal catheter hub 26, another structure (not shown) can be attached to the proximal catheter body section 20.

[0023] As shown in Figures 4-7, the catheter body 18 of the intravascular catheter 10 generally comprises a hypotube structure 38, an inner polymeric liner 40 (Figures 6 and 7) disposed within the hypotube structure 38, and a tie layer 42 (Figures 6 and 7) that attaches the inner polymeric liner 40 to the hypotube structure 38. Importantly, by selectively applying (or removing) material that forms the tie layer 42, the bending stiffness of the distal catheter body section 22 (Figure 3) is reduced such that a certain length of the distal portion of the inner polymeric liner 40 is not continuously attached to the hypotube structure 12. This can improve mobility of the catheter body 18 through a patient's vasculature.

[0024] The hypotube structure 38 has an elongated tubular body 44 with a proximal end 46 and a distal end 48, a hypotube pattern 50 of openings 50a and solid elements 50b formed at the distal end 48 of the tubular body 44, and an inner hypotube lumen 52 extending between the proximal end 46 and the distal end 48 of the tubular body 44. The tubular body 44 can be constructed of any of a variety of suitable materials, such as materials that are rigid but have some flexibility when used to form very thin structures, such as the walls of the tubular body 44. Examples of such materials include metals (e.g., stainless steels such as 304 stainless steel, 316 stainless steel, 316L stainless steel, nickel chromium (NiCr) steel, nickel titanium alloys (e.g., Nitinol), cobalt / chromium), or various plastics. The dimensions of the tubular body 44 can be suitable for one or more desired applications of the intravascular catheter 10. For example, the outer diameter of tubular body 44 can range from 0.005 to 0.080 inches. The inner diameter of tubular body 44 (i.e., the diameter of inner hypotube lumen 52) can range from 0.002 to 0.070 inches.

[0025] In the illustrated embodiment, the hypotube pattern 50 takes the form of a brick pattern, the openings 50a take the form of slots, and the solid elements 50b take the form of struts. In an alternative embodiment shown in Figure 8, the hypotube pattern 50' formed in the distal end 48 of the tubular body 44 can have openings in the form of slits 50a' (which can also be oriented in a circumferential direction (perpendicular to the longitudinal axis of the tubular body 44) or a helical direction (at an oblique angle to the longitudinal axis of the tubular body 44)) and solid elements in the form of spines 50b' formed between the slits 50a'.

[0026] The hypotube pattern 50 or hypotube pattern 50' may be formed in the distal end 48 of the tubular body 44 by laser cutting, sawing (e.g., with a semiconductor dicing blade embedded with diamond grit), etching, water jet cutting, or electrical discharge machining, among others.

[0027] In the illustrated embodiment, the hypotube pattern 50 of apertures 50a and solid elements 50b (or hypotube pattern 50' of apertures 50a' and solid elements 50b') is arranged to increase the bending flexibility of the distal end of the intravascular catheter 10 while maintaining the axial stiffness (pushability) and torqueability of the intravascular catheter 10, thereby allowing the intravascular catheter 10 to be introduced and advanced through a patient's tortuous vascular system. By controlling and varying the spacing, width and shape of the apertures 50a, the bending deflection profile and torsional stiffness of the hypotube structure 38, and thus the distal catheter body section 22 (see FIGS. 2 and 3), can be selectively altered.

[0028] As shown in Figures 6 and 7, the inner polymer liner 40 is disposed within the inner hypotube lumen 52. As further shown in Figure 9, the inner polymer liner 40 comprises an elongated polymer tube 54 having a proximal end 58 and a distal end 60, and an inner liner lumen 56 extending between the proximal end 58 and the distal end 60 of the polymer tube 54. The inner surface of the polymer tube 54 may be lubricious to facilitate the passage of a medical device (e.g., another catheter, a guide member, an embolic protection device, a stent, a thrombus removal device, or any combination thereof) through the inner liner lumen 56. For example, the material forming the entire polymer tube 54 may be lubricious. Examples of such materials include, but are not limited to, polytetrafluoroethylene (PTFE), expanded PTFE (ePTFE, e.g., unidirectional ePTFE or bidirectional ePTFE), fluoropolymer, perfluoroalkoxy, alkane (PFA), fluorinated ethylene polyethylene (FEP), polyethylene (PE), or any combination thereof. Other examples of materials from which the polymer tube 54 can be formed include, but are not limited to, low density polyethylene (LDPE) (e.g., about 42D), high density polyethylene (HDPE), or any combination thereof.

[0029] The polymer tube 54 has a unitary construction, i.e., is formed as a single piece, such that the polymer tube 54 is continuous along the entire length of the polymer tube 54. In a preferred embodiment, the polymer tube 54 is unreinforced (meaning that there are no metal elements disposed within the wall of the polymer tube 54 that function to increase the radial strength of the polymer tube 54), thereby minimizing the bending stiffness imparted by the inner polymer liner 40 to the distal catheter body section 22 (see FIG. 3). As will be explained in more detail below, because the polymer tube 54 is unreinforced, it is able to expand radially within the inner hypotube lumen 52 of the hypotube structure 38, thereby reducing the wall thickness of the polymer tube 54 and ensuring a continuous intimate (but not continuous bond) contact between the polymer tube 54 and the inner hypotube lumen 52 of the hypotube structure 38 (i.e., the hypotube structure 38 is in contact with the entirety of all solid elements of the hypotube structure 38).

[0030] The wall thickness of the distal end 60 of the polymer tube 54 can be 0.01 inches or less. In some embodiments, the wall thickness of the polymer tube 54 is substantially constant along the length of the polymer tube 54. In other embodiments, the wall thickness of the polymer tube 54 can decrease toward the distal end 50 (e.g., the thickness of the polymer tube 54 can decrease from the proximal end 48 to the distal end 50 of the polymer tube 54). The inner diameter of the polymer tube 54 (i.e., the diameter of the inner liner lumen 56) can be substantially constant along the entire length of the polymer tube 54. In other embodiments, the inner diameter of the polymer tube 54 can vary, for example, by continuously tapering from the proximal end 48 to the distal end 50 of the polymer tube 54 or by a step change. In any embodiment, the inner polymer liner 40 can have a pattern of openings (e.g., slots or slits) and solid elements (e.g., struts or ribs) (not shown) to increase the bending flexibility of the distal catheter body section 22, for example, as described in U.S. Patent Publication No. 2020 / 0129733, which is expressly incorporated by reference herein.

[0031] The tie layer 42 may be constructed of a suitable material, such as polyurethane (e.g., Tecoflex™), Pebax®, and nylon. The tie layer 42 may have a thickness of about 0.005 inches or less, and in some embodiments about 0.001 inches, and possibly 0.0001 inches or less. The tie layer 42 generally extends along at least 10-20 cm of the distal catheter body section 22, and typically is less than about 50 cm along the length of the catheter body 18.

[0032] 7, the tie layer 42 has a tie layer pattern 62 of openings 62a and solid elements 62b complementary to the hypotube pattern 50 such that the tie layer 42 intermittently attaches the inner polymer liner 40 to the solid elements 50b of the hypotube structure 38 along the length of the hypotube pattern 50, resulting in at least one discrete bonded area 64 between the hypotube structure 38 and the inner polymer liner 40, and at least one non-bonded area 66 between the hypotube structure 38 and the inner polymer liner 40. In the illustrated embodiment, the tie layer pattern 62 is complementary to the hypotube pattern 50 such that a plurality of discrete bonded areas 64 are formed between the hypotube structure 38 and the inner polymer liner 40, and a plurality of non-bonded areas 66 are formed between the hypotube structure 38 and the inner polymer liner 40.

[0033] Preferably, the tie layer 42 intermittently attaches the inner polymer liner 40 to the solid elements 50b of the hypotube structure 38 along the entire length of the hypotube pattern 50, although in alternative embodiments, the tie layer 42 can intermittently attach the inner polymer liner 40 to the solid elements 50b of the hypotube structure 38 along less than the entire length of the hypotube pattern 50, so long as the unreinforced inner polymer liner 40 does not collapse under vacuum (i.e., does not protrude into the inner hypotube lumen 52). For example, it is desirable for the discrete bond regions 64 to extend along at least 50%, and preferably at least 75%, of the length of the hypotube pattern 50. By intermittently attaching the inner polymer liner 40 to the solid element 50b of the hypotube structure 38 along the length of the distal end 48 of the tubular body 44, a greater length of the inner polymer liner 40 is not bonded to the hypotube structure 38, including a portion of the inner polymer liner 40 that spans the opening 50a and a portion of the inner polymer liner 40 that is below the solid element 50b.

[0034] Thus, the total area of ​​the discrete bonded regions 64 is no more than a percentage of the total area of ​​the inner surface of the solid elements 50b of the hypotube structure 38 along the length of the distal end 48 of the tubular body 44 of the hypotube structure 38. In one embodiment, the total area of ​​the discrete bonded regions 64 is no more than 75% of the total area of ​​the inner surface of the solid elements 50b of the hypotube structure 38 along the length of the distal end 48 of the tubular body 44 of the hypotube structure 38. In another embodiment, the total area of ​​the discrete bonded regions 64 is no more than 25% of the total area of ​​the inner surface of the solid elements 50b of the hypotube structure 38 along the length of the distal end 48 of the tubular body 44 of the hypotube structure 38.

[0035] In the embodiment shown in FIG. 7, the total area of ​​the discrete bonded regions 64 is equal to 50% of the total area of ​​the inner surface of the solid elements 50b of the hypotube structure 38 along the length of the distal end 48 of the tubular body 44 of the hypotube structure 38. This should be contrasted with the embodiment of FIG. 1, in which the inner polymer liner 4 is intimately and continuously bonded to the inner surface of the hypotube structure 3 (i.e., the total area of ​​the bonded regions where the inner polymer liner 4 is bonded to the solid elements 5 of the hypotube structure 3 is 100%). Assuming that the hypotube structure 38 of the embodiment of FIG. 7 is identical to the hypotube structure 3 and that the material and thickness constituting the inner polymer liner 40 are the same as the material and thickness constituting the inner polymer liner 4, the total area of ​​the bonded regions between the hypotube structure 38 and the inner polymer liner 40 of the embodiment of FIG. 7 is half that of the total area of ​​the bonded regions between the hypotube structure 3 and the inner polymer liner 4 of the embodiment of FIG. 1, resulting in a reduction in the bending stiffness of the composite structure formed by the hypotube structure and the inner polymer liner by approximately a factor of two.

[0036] 7 illustrates the discrete bonded regions 64 as fully corresponding to the solid elements 50b of the hypotube structure 38 over the entire length of the distal end 48 of the tubular body 44 of the hypotube structure 38, it should be understood that such an arrangement is not required. In one embodiment, the discrete bonded regions 64 fully correspond to the solid elements 50b of the hypotube structure 38 over a very localized length of the distal end 48 of the tubular body 44 of the hypotube structure 38, for example, over a centimeter or two.

[0037] In another embodiment, the hypotube pattern 50 and the tie layer pattern 62 can complement each other such that the total area of ​​the discrete bonded regions 64 formed between the hypotube structure 38 and the inner polymeric liner 40 is, on average, no more than a sufficient percentage of the total area of ​​the inner surface of the solid elements 50b of the hypotube structure 38 along the length of the distal end 48 of the tubular body 44 of the hypotube structure 38, as shown in FIG. 10. In that case, the total area of ​​the discrete bonded regions 64 is less than 50% of the total area of ​​the inner surface of the solid elements 50b of the hypotube structure 38 along the hypotube pattern 50. Each of the hypotube pattern 50 and the tie layer pattern 62 can be periodic in nature. Because the hypotube pattern 50 and the tie layer pattern 62 are predictable, a consistent percentage of the total area of ​​the discrete bonded regions 64 to the total area of ​​the inner surface of the solid elements 50b of the hypotube structure 38 can be achieved during manufacturing. In that case, the period of the hypotube pattern 50 and the period of the bonding layer pattern 62 may be the same or different from one another. In another embodiment, one or both of the hypotube pattern 50 and the bonding layer pattern 62 may be randomized, as shown in FIG.

[0038] A pattern of discrete bond areas 64 may be formed between the hypotube structure 38 and the inner polymeric liner 40 at the intersections of the solid elements 50b of the hypotube pattern 50 and the solid elements 54b of the tie layer pattern 62. The pattern of discrete bond areas 64 imparted to the bond between the inner polymeric liner 40 and the hypotube structure 38 may take virtually any configuration.

[0039] For example, as shown in FIG. 12, a circumferential band pattern of discrete bonded regions 64a can be formed between the hypotube structure 38 (not shown in FIG. 12 for clarity) and the inner polymer liner 40. In the illustrated embodiment, the circumferential band pattern of discrete bonded regions 64a is linear, but in alternative embodiments, the circumferential bands of discrete bonded regions 64a can be sinusoidal, for example. To form the circumferential bands of discrete bonded regions 64a, the solid elements 62b of the bonding layer pattern 62 can be formed as circumferential bands that periodically intersect with the solid elements 50b of the hypotube pattern 50 to form the circumferential band pattern of discrete bonded regions 64a. In another embodiment, as shown in FIG. 13, a spiral pattern of discrete bonded regions 64b can be formed between the hypotube structure 38 (not shown in FIG. 13 for clarity) and the inner polymer liner 40. In that case, the solid elements 62b of the bonding layer pattern 62 may be formed as spirals that periodically intersect with the solid elements 50b of the hypotube pattern 50 to form a helical pattern of discrete bonded regions 64b. Although the helical pattern of discrete bonded regions 64b is shown in Figure 13 as having a constant pitch and width, the helical pattern of discrete bonded regions 64b may alternatively have a varying pitch and / or width.

[0040] 7, 10 and 11, the tie layer 42 is disposed on the outer surface of the inner polymer liner 40, however, the tie layer may be embedded within the inner polymer liner. For example, in an alternative embodiment shown in FIG. 14, the inner polymer liner 40' may have an opening 68 that extends completely or partially through the polymer tube 54, and the tie layer 42' may be embedded within the opening 68. In that case, at least one discrete bonded area 64 is formed between the hypotube structure 38 and the inner polymer liner 40, and at least one non-bonded area 66 is formed between the hypotube structure 38 and the inner polymer liner 40.

[0041] While in the embodiment shown in Figures 4-14, the catheter body 18 does not have a polymer jacket, an alternative embodiment of the catheter body 18' shown in Figure 15 includes an outer polymer jacket 70 disposed on the outer diameter of the hypotube structure 38 to provide a seal and minimize the outer surface roughness imparted by the hypotube pattern 50 of openings 50a and solid elements 50b while still providing flexibility. In some embodiments, the inner polymer liner 40 (or 40') and tie layer 42 (or 42') can be arranged in the manner shown in Figures 7, 10, 11 and 14 to form at least one discrete bonded area 64 between the solid elements 62b of the hypotube structure 38 and the inner polymer liner 40 (or 40').

[0042] In another embodiment shown in FIGS. 16A-16C, the bonding layer 42″ has a bonding layer pattern 62 of openings 62a and solid elements 62b complementary to the hypotube pattern 50, such that the bonding layer 42″ intermittently attaches the inner polymeric liner 40 to the outer polymeric jacket 70 through at least a portion of the openings 50a of the hypotube pattern 50 of the hypotube structure 38. As a result, at least one discrete bonded area 64 is formed between the hypotube structure 38 and the outer polymeric jacket 70, and at least one non-bonded area 66 is formed between the hypotube structure 38 and the inner polymeric liner 40. In the illustrated embodiment, the bonding layer pattern 62 is complementary to the hypotube pattern 50, such that a plurality of discrete bonded areas 64 are formed between the hypotube structure 38 and the outer polymeric jacket 70, and a plurality of non-bonded areas 66 are formed between the hypotube structure 38 and the inner polymeric liner 40. In the embodiment shown in FIG. 16A, the bonding layer 42″ intermittently bonds the inner polymer liner 40 to the outer polymer jacket 70 through all of the openings 50a of the hypotube pattern 50 of the hypotube structure 38, while in the embodiment shown in FIG. 16B, the bonding layer 42″ intermittently bonds the inner polymer liner 40 to the outer polymer jacket 70 through all of the openings 50a of the hypotube pattern 50 of the hypotube structure 38. In the embodiment shown in FIG. 16C, the bonding layer 42″ also intermittently bonds the inner polymer liner 40 to the hypotube structure 38, forming discrete bonded areas 64 between some, but not all, of the solid elements 62b of the hypotube structure 38 and the inner polymer liner 40.

[0043] Having described the structure and configuration of the intravascular catheter 10, one exemplary method 100 of manufacturing the intravascular catheter 10 will now be described with reference to FIG.

[0044] The method 100 includes providing a hypotube structure. In particular, the method 100 includes providing a tubular body 202 (see FIG. 18 ) having a proximal end 204, a distal end 206, and a lumen 208 extending between the proximal end 204 and the distal end 206 (step 102), and forming a pattern 210 of openings 212 (e.g., slots) and solid elements 214 (e.g., struts) in the distal end 206 of the tubular body 202 (see FIG. 19 ) (step 104), such as by laser cutting, sawing (e.g., with a semiconductor dicing blade embedded with diamond grit), etching, water jet cutting, or electrical discharge machining, thereby creating the hypotube structure 200.

[0045] The method 100 further includes providing (step 106) a polymer tube 216 having a proximal end 218, a distal end 220, and a lumen 222 extending between the proximal end 218 and the distal end 220 (see FIG. 20). The polymer tube 216 may be composed of, for example, one or more of PTFE, ePTFE, fluoropolymer, PFA, FEP, and PE. The distal end 218 of the polymer tube 216 may have a wall thickness of 0.001 inches or less. Preferably, the polymer tube 216 is unreinforced, such that the bending flexibility of the resulting distal end of the intravascular catheter is not reduced and the polymer tube 216 is capable of radial expansion. The method 100 may optionally include forming a pattern of openings and solid elements in the distal end 218 of the polymer tube 216.

[0046] The method 100 further includes disposing (step 108) the polymer tube 216 within the lumen 206 of the hypotube structure 200 (see FIG. 21). As a result, the polymer tube 216 functions as an inner polymer liner for the hypotube structure 200. The method further includes expanding (step 110) the polymer tube 216 radially within the lumen 206 of the hypotube structure 200, thereby reducing a wall thickness of the polymer tube 216 and forming a continuous bond between the exterior of the polymer tube 216 and the interior of the hypotube structure 200. The method 100 further includes attaching (step 112) the polymer tube 216 to the solid element 214 of the hypotube structure 200 at at least one discrete bond area 224 along the length of the distal end 206 of the tubular body 202 (see FIG. 22). In the illustrated method, the discrete bonded region(s) 224 have a circumferential band pattern, however, it should be understood that the discrete bonded region(s) 224 may alternatively have any suitable pattern, including a helical pattern having a constant pitch / width or a variable pitch / width. Preferably, the total area of ​​the discrete bonded region(s) 224 is 75% or less, more preferably 50% or less, and even more preferably 25% or less of the total area of ​​the inner surface of the solid element 214 of the hypotube structure 200 along the distal end 206 of the hypotube structure 200.

[0047] The polymer tube 216 can be intermittently attached to the solid elements 214 of the hypotube structure 200 using a tie layer 226 either during or after expansion of the polymer tube 216 within the lumen 206 of the hypotube structure 200, which can be accomplished in any of a variety of ways.

[0048] In one method, the bonding layer 226 is provided on the polymer tube 216 prior to placing the polymer tube 216 within the lumen 206 of the hypotube structure 200, and in that case, the polymer tube 216 is intermittently attached to the solid element 214 of the hypotube structure 200 via the bonding layer 226 during expansion of the polymer tube 216 within the lumen 206 of the hypotube structure 200.

[0049] In one embodiment, the bonding layer 226a may be formed as a positive pattern of adhesive material (i.e., additive process) on the exterior surface of the polymer tube 216, as shown in FIG. 23, thereby forming a positive adhesive pattern (corresponding to the discrete bonded regions 224). The positive pattern of adhesive material may be comprised of any of the materials previously mentioned (e.g., polyurethane, Pebax®, nylon) or polymers having higher stiffness than typical bond layer polymers, in addition to adhesives such as, for example, heat-activated adhesives, catalyst-activated adhesives, solvent-activated adhesives, etc. The positive pattern of adhesive material may be formed on the exterior surface of the polymer tube 216, for example, by providing a patterned mask (negative of the positive adhesive pattern) on the exterior surface of the polymer tube 216, uniformly applying the adhesive material onto the patterned mask (e.g., by dispersion coating, e.g., film casting or dip coating, spraying, etc.), and then removing the patterned mask from the polymer tube 216, three-dimensional (3D) printing, inkjet printing, etc. In the illustrated method, bonding layer 226a has a circumferential band pattern, however, it should be understood that bonding layer 226a may alternatively have any suitable pattern, including a spiral pattern having a constant pitch / width or a variable pitch / width.

[0050] In other embodiments, a continuous bonding layer 226' may first be formed on the exterior surface of the polymer tube 216 using a suitable process (e.g., by dispersion coating, e.g., film casting or dip coating, or spraying, etc.) as shown in FIG. 24, and then bonding patterns 224b (at least a portion of which intersect with the solid elements 214 of the hypotube structure 200 correspond to the discrete bonding areas 224) may be formed on the continuous bonding layer 226' as shown in FIG. 25 (e.g., by melting or otherwise activating the adhesive properties of areas of the continuous bonding layer 226' corresponding to the bonding patterns 224b); or a continuous bonding layer 226' may be formed on the exterior surface of the polymer tube 216 as shown in FIG. 26 (e.g., by melting or otherwise activating the adhesive properties of areas of the continuous bonding layer 226' corresponding to the bonding patterns 224b). 27, a positive pattern 228 of non-adhesive material is formed on the bonded layer 226' (i.e., an additive process) to form a pattern 226c of adhesive material (at least a portion of which intersects with the solid elements 214 of the hypotube structure 200 corresponds to the discrete adhesive regions 224) outside the positive pattern 228 of non-adhesive material; or a negative pattern 230 in the continuous bonded layer 226' is ablated (i.e., a subtractive process) to form a positive pattern 226d of adhesive material (at least a portion of which intersects with the solid elements 214 of the hypotube structure 200 corresponds to the discrete adhesive regions 224) outside the negative pattern 230. Of note, photolithography can be used to form a pattern of active / inactive regions, or a photosensitive material can be prepared in a positive or negative pattern. Either the exposed or unexposed material is activated or inactivated as an adhesive, or is subsequently removed, and the remaining material acts as an adhesive.

[0051] Alternatively, a bonding layer 226 is provided on the polymer tube 216 after placement within the lumen 206 of the hypotube structure 200, in which case the polymer tube 216 is intermittently attached to the solid element 214 of the hypotube structure 200 via the bonding layer 226 after expansion of the polymer tube 216 within the lumen 206 of the hypotube structure 200.

[0052] In one embodiment, as shown in FIG. 28, liquid adhesive is applied through the openings 212 of the hypotube structure 200, causing the liquid adhesive to penetrate between the solid elements 214 of the hypotube structure 200 and the polymer tube 216, thereby forming a bonding pattern 224e (at least a portion of which intersects with the solid elements 214 of the hypotube structure 200 corresponds to one or more discrete bonding areas 224).

[0053] The method 100 optionally includes attaching an outer polymer jacket (not shown) to the outside of the hypotube structure 200 (step 114). In this case, the polymer tube 216 is intermittently attached to the outer polymer jacket at at least one discrete bonded area along the length of the distal end 206 of the tubular body 202. In this case, instead of intermittently attaching the polymer tube 216 to the solid element 214 of the hypotube structure 200 via the bonding layer 226 in step 112, the polymer tube 216 may be intermittently attached to the outer polymer jacket via the bonding layer 226. In other embodiments, the polymer tube 216 may be intermittently attached to both the solid element 214 of the hypotube structure 200 and the outer polymer jacket via the bonding layer 226.

[0054] Finally, the method 100 includes attaching a proximal catheter hub 220 to the proximal end 204 (not shown) of the hypotube structure 200 (step 116 ).

[0055] While specific embodiments have been shown and described herein, they are not intended to limit the disclosed invention, and it will be apparent to those skilled in the art that various changes, modifications and alterations (e.g., various part dimensions, combinations of parts) can be made without departing from the scope of the disclosed invention, which is defined only by the following claims and equivalents thereof. Accordingly, the specification and drawings are to be regarded in an illustrative sense, and not in a restrictive sense. The various embodiments shown and described herein are intended to cover alternatives, modifications and equivalents of the disclosed invention, which may fall within the scope of the appended claims.

Claims

1. A method for manufacturing an intravascular catheter, comprising: providing a hypotube structure having a tubular body having a proximal end, a distal end, a pattern of openings and solid elements disposed at the distal end of the tubular body, and a hypotube lumen extending between the proximal and distal ends of the tubular body; providing a polymer tube having a tube lumen; providing an outer polymer jacket; attaching the outer polymer jacket to an outer surface of the hypotube structure; placing the polymer tube within the hypotube lumen; radially expanding the polymer tube within the hypotube lumen; and intermittently attaching the polymer tube to at least a portion of a solid element of the hypotube structure and / or the outer polymer jacket at at least one discrete adhesive area along the length of the distal end of the tubular body.

2. In the method according to claim 1, The method of claim 1, wherein the polymer tube is intermittently attached to a solid element of the hypotube structure at at least one discrete bond area along the length of the distal end of the tubular body.

3. In the method according to claim 1, The method of claim 1, wherein the polymeric tube is intermittently attached to an outer polymeric jacket at at least one discrete bonded area along the length of the distal end of the tubular body.

4. In the method according to claim 3, The method of claim 1, wherein the polymer tubes are intermittently attached to the outer polymer jacket through openings in a hypotube pattern of the hypotube structure.

5. In the method according to claim 1, wherein the polymer tube is attached to both at least a portion of the solid element of the hypotube structure and the outer polymer jacket in at least one discrete bond area along the length of the distal end of the tubular body.

6. In the method according to claim 1, The method, wherein the polymer tube is unreinforced.

7. The method according to claim 1, The method, wherein the distal end of the polymer tube has a wall thickness of 0.001 inches or less.

8. The method according to claim 1, The method of claim 1, wherein the radially expanded polymer tube is in intimate contact with all of the solid elements of the hypotube structure.

9. The method according to claim 1, The method further comprises providing a bonding layer on the polymer tube, the bonding layer intermittently attaching the polymer tube to at least a portion of a solid element of the hypotube structure and / or the outer polymer jacket in at least one discrete bonded area along the length of the distal end of the tubular body.

10. The method according to claim 9, The method of claim 1, wherein the tie layer is applied to the polymer tube prior to placing the polymer tube within the hypotube lumen.

11. The method according to claim 10, The method of claim 1, wherein the tie layer is applied to an exterior surface of the polymer tube.

12. The method according to claim 11, The method of claim 1, wherein providing the tie layer on the outer surface of the polymer tube comprises dispersion coating the tie layer on the outer surface of the polymer tube.

13. The method according to claim 11, and forming a positive pattern of adhesive material on the outer surface of the polymer tube, wherein at least a portion of the positive pattern of adhesive material corresponds to the at least one discrete adhesive area.

14. The method according to claim 11, The method according to claim 1, wherein the tie layer is a continuous tie layer.

15. The method according to claim 14, The method further comprising forming an adhesive pattern in the continuous bonding layer, at least a portion of the adhesive pattern corresponding to the at least one discrete adhesive area.

16. The method according to claim 15, 10. The method of claim 9, wherein forming an adhesive pattern in the continuous bonding layer comprises melting or otherwise activating adhesive properties in areas of the continuous bonding layer corresponding to the adhesive pattern.

17. The method according to claim 15, The method further comprises providing a positive pattern of non-adhesive material on the continuous bonding layer to form a negative pattern of adhesive material outside the positive pattern of non-adhesive material, wherein at least a portion of the positive pattern of adhesive material corresponds to the at least one discrete adhesive region.

18. The method according to claim 14, The method further comprises a step of ablating the negative pattern in the continuous bonding layer to form a positive pattern of adhesive material outside the negative pattern, at least a portion of the positive pattern of adhesive material corresponding to the at least one discrete adhesive area.

19. The method according to claim 10, ablating a negative pattern in the polymer tube to form a negative polymer tube pattern, and applying the bonding layer to the polymer tube includes disposing an adhesive material in the negative polymer tube pattern to form a pattern of adhesive material, at least a portion of the adhesive pattern corresponding to the at least one discrete adhesive area.

20. The method according to claim 9, the method comprising applying the tie layer to the polymer tube after placing the polymer tube within the hypotube lumen.

21. The method according to claim 20, 10. The method of claim 9, wherein applying the bonding layer to the polymer tube comprises applying a liquid adhesive through an opening in the hypotube structure such that the liquid adhesive penetrates between a solid element of the hypotube structure and the polymer tube.

22. The method according to claim 2, The method of claim 1, wherein the polymer tube is in intimate contact with all of the solid elements of the hypotube structure.

23. A method for manufacturing an intravascular catheter, comprising: providing an elongate tubular body having a proximal end, a distal end, and a tubular body lumen extending between the proximal and distal ends of the tubular body; providing a polymer tube having a tube lumen; disposing the polymer tube within the tubular body lumen; radially expanding the polymer tube within the tubular body lumen; and intermittently attaching the polymer tube to the tubular body at at least one discrete adhesive area along the length of the distal end of the tubular body.

24. The method according to claim 23, The method, wherein the polymer tube is unreinforced.

25. The method according to claim 23, The method, wherein the distal end of the polymer tube has a wall thickness of 0.001 inches or less.

26. The method according to claim 23, a radially expanded polymeric tube in continuous, intimate contact with said tubular body.

27. The method according to claim 23, The method further comprises providing a bonding layer on the polymer tube, the bonding layer intermittently attaching the polymer tube to the tubular body in at least one discrete bonded area along the length of the distal end of the tubular body.

28. The method according to claim 27, The method of claim 1, wherein the tie layer is applied to the polymer tube prior to placing the polymer tube within the tubular body lumen.

29. The method according to claim 28, The method of claim 1, wherein the tie layer is applied to an exterior surface of the polymer tube.

30. The method according to claim 29, The method of claim 1, wherein providing the tie layer on the outer surface of the polymer tube comprises dispersion coating the tie layer on the outer surface of the polymer tube.

31. The method according to claim 29, and forming a positive pattern of adhesive material on the outer surface of the polymer tube, wherein at least a portion of the positive pattern of adhesive material corresponds to the at least one discrete adhesive area.

32. The method according to claim 29, The method according to claim 1, wherein the tie layer is a continuous tie layer.

33. The method according to claim 32, The method further comprising forming an adhesive pattern in the continuous bonding layer, at least a portion of the adhesive pattern corresponding to the at least one discrete adhesive area.

34. The method according to claim 33, 10. The method of claim 9, wherein forming an adhesive pattern in the continuous bonding layer comprises melting or otherwise activating adhesive properties in areas of the continuous bonding layer corresponding to the adhesive pattern.

35. The method according to claim 33, The method further comprises providing a positive pattern of non-adhesive material on the continuous bonding layer to form a negative pattern of adhesive material outside the positive pattern of non-adhesive material, wherein at least a portion of the positive pattern of adhesive material corresponds to the at least one discrete adhesive region.

36. The method according to claim 32, The method further comprises a step of ablating the negative pattern in the continuous bonding layer to form a positive pattern of adhesive material outside the negative pattern, at least a portion of the positive pattern of adhesive material corresponding to the at least one discrete adhesive area.

37. The method according to claim 28, ablating a negative pattern in the polymer tube to form a negative polymer tube pattern, and applying the bonding layer to the polymer tube includes disposing an adhesive material in the negative polymer tube pattern to form a pattern of adhesive material, at least a portion of the adhesive pattern corresponding to the at least one discrete adhesive area.

38. The method according to claim 27, the method comprising applying the tie layer to the polymer tube after placing the polymer tube within the hypotube lumen.

39. The method according to claim 38, 10. The method of claim 9, wherein applying the bonding layer to the polymer tube comprises applying a liquid adhesive through an opening in the hypotube structure such that the liquid adhesive penetrates between a solid element of the hypotube structure and the polymer tube.

40. The method of claim 1, The method, wherein the polymer tube is not attached to the solid element of the hypotube structure.

41. The method according to claim 2, 10. The method of claim 9, wherein intermittently attaching the polymer tube to a solid element of the hypotube structure comprises applying a liquid adhesive through an opening in the hypotube structure and allowing the liquid adhesive to penetrate between the solid element of the hypotube structure and the polymer tube.

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