Core assembly of a medical device delivery system

Abstract

A stent delivery system may include a core assembly sized for insertion into a body cavity and configured to advance a stent toward a treatment location in the body cavity. The core assembly may include a longitudinally extending tube having a lumen and a spiral cut extending along the tube. An elongated wire may extend through the lumen. The wire may have a midsection disposed distally of the tube. The system may also include a stent carried by the midsection.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to U.S. Patent Application No. 16 / 001,842, filed on June 6, 2018, which is incorporated herein by reference in its entirety. Background Art

[0003] The walls of the vascular system, particularly the walls of arteries, may develop pathological dilated areas called aneurysms, which typically have weak walls that are prone to rupture. Aneurysms are typically caused by weakening of the blood vessel wall due to disease, injury, or congenital abnormalities. Aneurysms occur in different parts of the body, and the most common are abdominal aortic aneurysms and brain (e.g., cerebral) aneurysms in the neurovascular vessels. When the weakened walls of the aneurysm rupture, especially if it is a cerebral aneurysm, death can result.

[0004] Aneurysms are typically treated by excluding or at least partially isolating a weakened portion of a blood vessel from the arterial circulation. For example, conventional aneurysm treatments include: (i) surgical clipping, in which a metal clip is secured around the base of the aneurysm; (ii) packing the aneurysm with small flexible coils (microcoils); (iii) "filling" the aneurysm with embolic materials; (iv) occluding the parent vessel supplying the aneurysm using a detachable balloon or coil; and (v) endovascular stenting.

[0005] As is well known, intravascular stents are used in the medical field to treat vascular stenosis or aneurysms. A stent is a prosthesis that expands radially or otherwise within a blood vessel or cavity to support the vessel from collapsing. Methods for delivering these intravascular stents are also well known.

[0006] The conventional method of introducing the compressed stent into the blood vessel and positioning it in the stenosis or aneurysm region includes percutaneously advancing the distal portion of the guide catheter through the patient's vascular system until the distal portion is close to the stenosis or aneurysm. The guide wire in the second inner catheter and the inner catheter is advanced through the distal portion of the guide catheter. The guide wire is then pushed out of the distal portion of the guide catheter into the blood vessel until the distal portion of the guide wire carrying the compressed stent is positioned at the lesion point in the blood vessel. Then, the compressed stent is released and expanded so that it supports the blood vessel at the lesion point. Summary of the invention

[0007] For example, the present invention is exemplified according to the various aspects described below. For convenience, various embodiments of various aspects of the present invention are described as numbered clauses (1, 2, 3, etc.). These clauses are provided as embodiments rather than limiting the present invention. It should be noted that any dependent clauses can be combined in any combination and placed in corresponding independent clauses (e.g., clause 1 or clause 25). Other clauses can be presented in a similar manner.

[0008] 1. A stent delivery system, comprising:

[0009] A core assembly sized for insertion into a body lumen, the core assembly configured to advance a stent toward a treatment location in the body lumen, the core assembly comprising:

[0010] a longitudinally extending tube having a lumen and a helical cut extending along the tube; and

[0011] an elongated wire extending through the lumen, the wire having a mid-portion disposed distally of the tube; and

[0012] A bracket is carried by the middle portion.

[0013] 2. A system according to clause 1, wherein the wire extends near the proximal end of the tube.

[0014] 3. A system according to any of clauses 1 to 2, wherein a proximal portion of the tube is fixed to the wire.

[0015] 4. A system according to clause 3, wherein a proximal portion of the tube is welded to the wire.

[0016] 5. A system according to any one of clauses 1 to 4, wherein a distal portion of the tube is fixed relative to the wire.

[0017] 6. The system of clause 5, wherein a restraint is coupled to the wire, and wherein a distal portion of the tube is welded to the restraint.

[0018] 7. The system of any one of clauses 1 to 6, wherein the system further comprises a catheter having a lumen, the lumen of the catheter being configured to receive the core assembly therethrough.

[0019] 8. The system of clause 7, wherein the tube is sized to substantially fill the lumen of the catheter.

[0020] 9. The system of clause 7, wherein the tube fills at least about 80% of the lumen of the catheter.

[0021] 10. The system of clause 7, wherein the tube fills at least about 90% of the lumen of the catheter.

[0022] 11. A system according to any one of clauses 1 to 10, wherein the proximal and distal portions of the tube are fixed so as to prevent compression or elongation of the tube.

[0023] 12. The system of any one of clauses 1 to 11, wherein the wall thickness of the tube is between about 50 and 60 microns.

[0024] 13. A system according to any one of clauses 1 to 12, wherein the longitudinal length of the tube is between about 400 and 600 mm.

[0025] 14. A system according to any of clauses 1 to 13, wherein the diameter of the wire tapers distally towards a distal end of the wire.

[0026] 15. A system according to any of clauses 1 to 14, wherein a portion of the intermediate portion of the wire has a substantially constant diameter along its length.

[0027] 16. A system according to any of clauses 1 to 15, wherein the wire has a constant diameter section overlapping the distal end of the tube.

[0028] 17. The system of clause 16, wherein the constant diameter section is between approximately 3 and 5 inches.

[0029] 18. The system of any of clauses 1 to 17, further comprising a restraint coupled to the wire and secured to the distal end of the tube.

[0030] 19. The system of any of clauses 1 to 18, wherein the tube is configured to bend preferentially before the wire.

[0031] 20. The system of any one of clauses 1 to 19, further comprising a conduit configured to receive the core assembly therethrough, and wherein the bending stiffness of the tube is configured to match the bending stiffness of the conduit.

[0032] 21. The system of clause 20, wherein, at least along a distal portion of the tube, the bending stiffness of the tube is less than 300% of the bending stiffness of the catheter.

[0033] 22. A system according to clause 21, wherein the distal portion of the tube spans at least 15 inches from the distal end of the tube.

[0034] 23. A system according to clause 21, wherein the distal portion of the tube spans at least 30 inches from the distal end of the tube.

[0035] 24. The system of any one of clauses 1 to 24, wherein the bending stiffness of the core assembly is adjusted by the pitch of the spiral cuts.

[0036] 25. A core assembly sized for insertion into a body lumen, the core assembly configured to advance a stent toward a treatment location in the body lumen, the core assembly comprising:

[0037] A hypotube having a proximal end, a distal end, a lumen, and a helical cutout extending along the hypotube; and

[0038] An elongated wire extends completely through the hypotube lumen, the wire having a distal portion extending distally beyond the hypotube lumen.

[0039] 26. The core assembly of clause 25, wherein the wire extends proximate a proximal end of the hypotube.

[0040] 27. The core assembly of any of clauses 25 to 26, wherein a proximal portion of the hypotube is secured to the wire.

[0041] 28. The core assembly of clause 27, wherein a proximal portion of the hypotube is welded to the wire.

[0042] 29. The core assembly of any of clauses 25 to 28, wherein a distal portion of the hypotube is fixed relative to the wire.

[0043] 30. The core assembly of clause 29, wherein a restraint is coupled to the wire, and wherein a distal portion of the hypotube is welded to the restraint.

[0044] 31. The core assembly of any of clauses 25 to 30, wherein the system further comprises a catheter having a lumen configured to receive the core assembly therethrough.

[0045] 32. The core assembly of clause 31 , wherein the hypotube is sized to substantially fill the lumen of the catheter.

[0046] 33. The core assembly of clause 31 , wherein the hypotube fills at least about 80% of the lumen of the catheter.

[0047] 34. The core assembly of clause 31 , wherein the hypotube fills at least about 90% of the lumen of the catheter.

[0048] 35. The core assembly of any of clauses 25 to 34, wherein the proximal and distal portions of the hypotube are secured so as to prevent compression or elongation of the hypotube.

[0049] 36. The core assembly of any of clauses 25 to 36, wherein the hypotube has a wall thickness of between about 50 and 60 microns.

[0050] 37. The core assembly of any of clauses 25 to 36, wherein the longitudinal length of the hypotube is between about 400 and 600 mm.

[0051] 38. The core assembly of any of clauses 25 to 37, wherein the diameter of the wire tapers distally towards the distal end of the wire.

[0052] 39. A core assembly according to any of clauses 25 to 38, wherein the intermediate portion of the wire has a substantially constant diameter along its length.

[0053] 40. The core assembly of any of clauses 25 to 39, wherein the wire has a constant diameter section overlapping a distal end of the hypotube.

[0054] 41. The core assembly of clause 40, wherein the constant diameter section is between about 3 and 5 inches.

[0055] 42. The core assembly of any of clauses 25 to 41, further comprising a restraint coupled to the wire and secured to the distal end of the hypotube.

[0056] 43. The core assembly of any of clauses 25 to 42, wherein the hypotube is configured to bend preferentially before the wire.

[0057] 44. The core assembly of any one of clauses 25 to 43, further comprising a conduit configured to receive the core assembly therethrough, and wherein the bending stiffness of the hypotube is configured to match the bending stiffness of the conduit.

[0058] 45. The core assembly of clause 44, wherein, at least along a distal portion of the hypotube, the bending stiffness of the hypotube is less than 300% of the bending stiffness of the catheter.

[0059] 46. ​​The core assembly of clause 45, wherein the distal portion of the hypotube spans at least 15 inches from the distal end of the hypotube.

[0060] 47. The core assembly of clause 45, wherein the distal portion of the hypotube spans at least 30 inches from the distal end of the hypotube.

[0061] 48. A medical device delivery system comprising:

[0062] a catheter having a lumen;

[0063] a core assembly configured to extend through the catheter lumen, the core assembly comprising:

[0064] elongated axis; and

[0065] A longitudinally extending tube is disposed on the shaft, the tube including a lumen, the lumen of the tube extending between a proximal end and a distal end, the distal end being fixed relative to the shaft at a first position, and the proximal end of the tube being fixed relative to the shaft at a second position such that the overall length of the tube is substantially fixed.

[0066] 49. A system according to clause 48, wherein the shaft has a substantially fixed length.

[0067] 50. The system of any of clauses 48 to 49, wherein the tube is not fixed to the shaft at an intermediate portion between a proximal end of the tube and a distal end of the tube.

[0068] 51. A system according to any of clauses 48 to 50, wherein the shaft extends away from the distal end of the tube.

[0069] 52. A system according to any of clauses 48 to 51, wherein the tube comprises a spiral cut in a side wall of the tube and extending along the length of the tube.

[0070] 53. A system according to any one of clauses 48 to 52, wherein the shaft extends proximate to the proximal end of the tube.

[0071] 54. A system according to any of clauses 48 to 53, wherein the proximal end of the tube is welded to the shaft.

[0072] 55. The system of any of clauses 48 to 54, wherein a restraint is coupled to the shaft, and wherein the distal end of the tube is welded to the restraint.

[0073] 56. The system of any of clauses 48 to 55, wherein the tube is sized to substantially fill the lumen of the catheter.

[0074] 57. The system of any of clauses 48 to 56, wherein the tube fills at least about 80% of the lumen of the catheter.

[0075] 58. The system of any of clauses 48 to 57, wherein the tube fills at least about 90% of the lumen of the catheter.

[0076] 59. The system of any one of clauses 48 to 58, wherein the wall thickness of the tube is between about 50 and 60 microns.

[0077] 60. A system according to any of clauses 48 to 59, wherein the longitudinal length of the tube is between about 400 and 600 mm.

[0078] 61. A system according to any of clauses 48 to 60, wherein the diameter of the shaft tapers distally towards the distal end of the shaft.

[0079] 62. A system according to any of clauses 48 to 61, wherein the intermediate portion of the shaft has a substantially constant diameter along its length.

[0080] 63. A system according to any of clauses 48 to 62, wherein the shaft has a constant diameter section overlapping the distal end of the tube.

[0081] 64. A system according to clause 63, wherein the constant diameter section is between approximately 3 and 5 inches.

[0082] 65. The system of any of clauses 48 to 64, further comprising a restraint coupled to the shaft and secured to the distal end of the tube.

[0083] 66. A system according to any of clauses 48 to 65, wherein the tube is configured to bend preferentially before the shaft.

[0084] 67. A system according to any of clauses 48 to 66, wherein the bending stiffness of the tube is configured to match the bending stiffness of the catheter.

[0085] 68. A system according to any of clauses 48 to 67, wherein, at least along a distal portion of the tube, the bending stiffness of the tube is less than 300% of the bending stiffness of the catheter.

[0086] 69. A system according to clause 68, wherein the distal portion of the tube spans at least 15 inches from the distal end of the tube.

[0087] 70. A system according to clause 68, wherein the distal portion of the tube spans at least 30 inches from the distal end of the tube.

[0088] 71. A method of operating a medical device delivery system, the method comprising:

[0089] Inserting a core assembly into the lumen of the catheter in a twisted configuration, the core assembly comprising:

[0090] a tube having a proximal end, a distal end, a lumen, and a helical cut extending along the tube; and

[0091] an elongated wire extending completely through the lumen, the wire having a distal portion extending distally beyond the lumen;

[0092] pushing the core assembly through the twisted conduit; and

[0093] Advancement of the core assembly through the twisted catheter is facilitated by pushing the core assembly, causing the tube to flex along the helical cutout without substantially compressing or extending the length of the tube.

[0094] 72. A method according to clause 71, wherein the tube is fixed at its proximal and distal ends relative to the elongation wire.

[0095] 73. A method according to any of clauses 71 to 72, wherein the tube is welded to the elongate wire at its proximal and distal ends.

[0096] 74. A method according to any of clauses 71 to 73, wherein a stent is carried by the core assembly.

[0097] 75. A method according to any one of clauses 71 to 74, wherein the wire extends near the proximal end of the tube.

[0098] 76. A system according to any of clauses 71 to 75, wherein the tube substantially fills the lumen of the catheter.

[0099] 77. The system of clause 76, wherein the tube fills at least about 80% of the lumen of the catheter.

[0100] 78. The system of clause 76, wherein the tube fills at least about 90% of the lumen of the catheter.

[0101] 79. The system of any one of clauses 71 to 78, wherein the wall thickness of the tube is between about 50 and 60 microns.

[0102] 80. A method according to any one of clauses 71 to 79, wherein the longitudinal length of the tube is between about 400 and 600 mm.

[0103] 81. A method according to any of clauses 71 to 80, wherein the diameter of the wire tapers distally towards the distal end of the wire.

[0104] 82. A method according to any of clauses 71 to 81, wherein the middle portion of the wire has a substantially constant diameter along its length.

[0105] 83. A method according to any of clauses 71 to 82, wherein the wire has a constant diameter section overlapping the distal end of the tube.

[0106] 84. The method of clause 83, wherein the constant diameter section is between approximately 3 and 5 inches.

[0107] 85. The method of any of clauses 71 to 84, further comprising a restraint coupled to the wire and secured to the distal end of the tube.

[0108] 86. A method according to any of clauses 71 to 85, wherein the tube is bent preferentially before the wire.

[0109] 87. A method according to any of clauses 71 to 86, wherein the bending stiffness of the tube is configured to match the bending stiffness of the catheter.

[0110] 88. A method according to clause 87, wherein, at least along a distal portion of the tube, the bending stiffness of the tube is less than 300% of the bending stiffness of the catheter.

[0111] 89. A method according to clause 88, wherein the distal portion of the tube spans at least about 15 inches from the distal end of the tube.

[0112] 90. The method of clause 88, wherein the distal portion of the tube spans at least about 30 inches from the distal end of the tube.

[0113] 91. A stent delivery system comprising:

[0114] a core member sized for insertion into a body lumen, the core assembly being configured to advance the stent toward a treatment location in the body lumen, the core assembly comprising:

[0115] a longitudinally extending tube having a lumen and a helical cut extending along the tube; and

[0116] an elongation wire coupled to the tube, the wire having an intermediate portion disposed distally of the tube;

[0117] a stent carried by the core member; and

[0118] A catheter is configured to receive the core assembly therethrough, wherein the bending stiffness of the tube is configured to match the bending stiffness of the catheter.

[0119] 92. A system according to clause 91, wherein, at least along a distal portion of the tube, the bending stiffness of the tube is less than 300% of the bending stiffness of the catheter.

[0120] 93. A system according to clause 92, wherein the distal portion of the tube spans at least 15 inches from the distal end of the tube.

[0121] 94. A system according to clause 92, wherein the distal portion of the tube spans at least 30 inches from the distal end of the tube.

[0122] Other features and advantages of the present invention will be explained in the following description, and part of it will be obvious from the description, or can be understood through the practice of the subject technology. The advantages of the present invention are realized and obtained by the structures specifically pointed out in the written description and its claims and the attached drawings.

[0123] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the present technology as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0124] Many aspects of the present disclosure may be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on clearly illustrating the principles of the present technology. For ease of reference, throughout this disclosure, the same reference numerals may be used to identify components or features that are identical or at least generally similar or analogous.

[0125] Figure 1 is a cross-sectional side view of a medical device delivery system according to some embodiments.

[0126] Figure 2A yes Figure 1 A side view of a core assembly of a medical device delivery system is shown.

[0127] Figure 2B yes Figure 2A A cross-sectional side view of a core assembly.

[0128] Figure 3 yes Figure 2A An enlarged detail view of a portion of the core assembly is shown.

[0129] Figure 4 and Figure 5 yes Figure 2B An enlarged detail view of a portion of the core assembly is shown.

[0130] Fig. 6A and Figure 6B is a graph of bending stiffness of components of a medical device delivery system according to some embodiments. DETAILED DESCRIPTION

[0131] Traditional medical device delivery systems can include a core member or core assembly configured to carry a medical device by a catheter. The core assembly can be a single continuous line, or in some embodiments, the core assembly can be a multi-member structure in which a line segment is connected end to end to a tubular segment. For example, the core assembly can include a proximal line, a tube (such as a hypotube) connected to the distal end of the proximal line at its proximal end, and a distal line connected to the distal end of the tube at its proximal end. Compared with solid wires that must be made into thinner or smaller diameters to become more flexible, the advantage of the tube is that it has a consistent and relatively large outer diameter that occupies a larger portion of the catheter lumen, which can reduce kinks or bends along its length in certain use environments. The tube can also be precisely customized so that it has desired flexibility in different parts along its length, for example, by changing the pitch of the spiral extension cutouts in the different segments of the tube, without changing or reducing the diameter of the tube.

[0132] However, the tubular core assembly is susceptible to compression and / or elongation during navigation through the catheter. This is particularly true for tubes with one or more spirally extending cutouts along the length of the tube. Such elongation or compression can adversely change the performance characteristics of the core assembly, such as flexibility, column strength, and navigability. In addition, elongation and compression can cause the clinician to lose the desired responsiveness during operation of the delivery system because the movement made by the clinician at the proximal end of the core assembly will not translate in a one-to-one manner with the movement of the core assembly in the distal portion of the delivery system.

[0133] For example, as the core assembly is advanced distally, a portion of the core assembly may resist movement more than another portion of the core assembly (e.g., due to frictional engagement with the inner wall of the catheter). If the distal portion of the core assembly resists distal movement to a greater extent than the proximal portion of the core assembly, the distal portion and the proximal portion will approach each other, resulting in compression or bending of the core assembly and a reduction in its total length. Conversely, if the proximal portion of the core assembly resists proximal movement to a greater extent than the distal portion, the proximal portion and the distal portion will move further, resulting in elongation of the core assembly and an increase in its total length. In some cases, the tubular core assembly may be compressed in some portions and elongated in other portions at the same time. An embodiment of the present technology provides a core assembly that provides the advantages of a tubular member while reducing the risk of compression or elongation. For example, the core assembly may include a longitudinally extending wire or shaft, and a tube (e.g., a hypotube with a helically extending cutout) surrounding the wire along a portion of the length of the wire. The tube may be fixed to the wire at the proximal and distal ends of the tube, thereby limiting the ability of the tube to elongate or compress relative to the wire.

[0134] References Figures 1 to 6B Specific details of several embodiments of the technology of the present invention are described. Although many embodiments are described below regarding devices, systems, and methods for treating cerebral embolism or intracranial embolism, other applications and other embodiments other than those described herein are also within the scope of the technology of the present invention. Further, embodiments of the technology of the present invention may have configurations, components, and / or procedures different from those shown or described herein. In addition, embodiments of the technology of the present invention may have configurations, components, and / or procedures other than those shown or described herein, and these and other embodiments may not have several of the configurations, components, and / or procedures shown or described herein without departing from the technology of the present invention.

[0135] As used herein, the term "distal" and "proximal" define a position or direction relative to a clinician or clinician's control device (e.g., a handle of a delivery catheter). For example, the term "distal" and "distal" refer to a position along the length of the device away from a clinician or clinician's control device or in a direction away from a clinician or clinician's control device. In a related embodiment, the term "proximal" and "proximal" refer to a position along the length of the device close to a clinician or clinician's control device or in a direction toward a clinician or clinician's control device. The title provided herein is for convenience only and should not be construed as limiting the disclosed subject matter.

[0136] Figures 1 to 5Embodiments of medical device delivery systems that can be used to deliver and / or deploy medical devices (such as, but not limited to, stents) into hollow anatomical structures (such as blood vessels) are depicted. The stents may include braided stents or other forms of stents, such as woven stents, knitted stents, laser cut stents, rolled stents, and the like. The stents may optionally be configured to act as a "flow shunt" device for treating aneurysms, such as those present in blood vessels including arteries in the brain or within the skull, or other locations in the body (such as peripheral arteries). The stent may optionally be similar to any version or size of the PIPELINE sold by Medtronic Neurovascular, Inc. of Irvine, California, USA. TM Embolic devices. The stent may alternatively include any suitable tubular medical device and / or other features as described herein. In some embodiments, the stent may be any of the stents described in U.S. Application No. 15 / 892,268, filed on February 8, 2018, entitled “VASCULAR EXPANDABLE DEVICES,” the entire contents of which are hereby incorporated by reference herein and become a part of this specification.

[0137] Figure 1 1 is a cross-sectional side view of a medical device delivery system 100 configured in accordance with an embodiment of the present technology. The delivery system 100 can be configured to carry a stent (or other vascular implant or device) 105 thereon to be advanced to a target site of a patient, for example, a site within a body cavity 113 (such as a blood vessel) through a surrounding elongated tube or catheter 101. The catheter 101 can slidably receive a core member or core assembly 103 configured to carry the stent 105 thereon. The depicted catheter 101 has a proximal portion 107 and an opposite distal portion 109 that can be positioned at a treatment site within a patient's body, and an internal lumen 111 extending from the proximal portion 107 to the distal portion 109. The catheter 101 has a distal opening at the distal portion 109 through which the core assembly 103 can be advanced beyond the distal portion 109 to expand or deploy the stent 105 within the body cavity 113. The proximal portion 107 can include a catheter hub (not shown). The catheter 101 can define a generally longitudinal dimension extending between a proximal portion 107 and a distal portion 109. The longitudinal dimension need not be straight along some or any of its length when the delivery system 100 is in use.

[0138] The delivery system 100 may be used with any number of catheters. For example, the catheter may optionally include a MARKSMAN® catheter of various lengths available from Medtronic Neurovascular, Inc., Irvine, California, USA. TMThe catheter may optionally include a microcatheter having an inner diameter of about 0.030 inches or less and / or an outer diameter of 3 French or less near the distal region. In lieu of or in addition to these specifications, the catheter may include a microcatheter configured to percutaneously access the internal carotid artery or another location within the neurovascular distal to the internal carotid artery.

[0139] The core assembly 103 may generally include any one or more components having sufficient flexibility and column strength to allow the stent 105 or other medical device to be moved through the catheter 101. Thus, the core assembly 103 may include: a wire, a tube (e.g., a hypotube), a braid, a coil, or other suitable one or more components, or a combination of one or more wires, one or more tubes, one or more braids, one or more coils, and the like. Figure 1 The depicted embodiment of the core assembly 103 is a multi-component construction that includes a longitudinally extending shaft or wire 104 and an elongated tube 106 surrounding at least a portion of the wire 104. A layer of lubricating material such as PTFE (polytetrafluoroethylene or TEFLON) may be included. TM ) or other lubricious polymer may cover some or all of the tube 106 and / or wire 104.

[0140] The wire 104 has a proximal portion 108 and a distal portion 110, which may optionally include a tip coil 112. The wire 104 may be constructed of materials including polymers and metals including nitinol and stainless steel. In some embodiments, the wire 104 tapers in the distal direction, having a larger diameter at the proximal portion 108 and a smaller diameter at the distal portion 110. The taper may be gradual and continuous along the length of the wire 104, or in some embodiments, the taper may vary at different portions of the wire 104. As described in more detail below, in some embodiments, the wire 104 may include one or more constant diameter sections in which the wire 104 does not taper. Such constant diameter sections may be used to use a single wire in conjunction with tubes 106 and stents 105 of different lengths.

[0141] The wire 104 may also include an intermediate portion 114 located between the proximal portion 108 and the distal portion 110. The intermediate portion 114 is a portion of the core assembly 103 that is positioned when the core assembly 103 is in a position such as Figure 1 The stent 105 extends on or above the portion in the pre-deployment configuration shown. The wire 104 may include one or more fluorine-safe markers (not shown), and such one or more markers may be positioned on a portion of the wire 104 not covered by the outer layer 117 (e.g., the proximal side of the outer layer 117). The portion of the wire 104 marked by the one or more markers and / or the proximal side of any outer layer 117 may include an exposed metal outer surface.

[0142] Tube 106 extends from proximal portion 116 to distal portion 118 and surrounds wire 104 along at least a portion of the length of wire 104. In some embodiments, distal portion 118 of tube 106 terminates proximal to intermediate portion 114 of wire 104 such that during operation, stent 105 is carried by intermediate portion 114 of wire 104 at a location distal to tube 106.

[0143] The tube 106 may have an "uncut" sidewall or a sidewall with no openings or voids formed therein. Alternatively, the tube 106 may have openings, voids, or cuts formed in the sidewall to enhance the flexibility of the tube. This may be accomplished by cutting a series of slits in the sidewall along part or all of the length of the tube, or cutting or drilling a pattern of other openings in the sidewall, or cutting spiral voids or helical cuts in the sidewall. For example, Figure 1 As shown, the tube 106 has a spirally extending void or cutout 115 in the sidewall extending from the proximal portion 116 to the distal portion 118. The cutout 115 may include multiple segments with different pitches, for example, the first segment 115a has a lower pitch than the second segment 115b. By varying the pitch in different segments of the cutout 115, the bending stiffness of the tube 106 can be precisely adjusted along the length of the tube 106. Although in Figure 1 Two sections of the cutout 115 are shown in FIG, but the tube 106 may have many different sections having different pitch sizes.

[0144] In some embodiments, for example where the delivery system will be used in narrow and / or tortuous vasculature (such as neurovasculature), the outer diameter of tube 106 can be relatively small (e.g., 0.040" or less, or 0.030" or less, or 0.027" or less, or about 0.020", or about .016"). In some embodiments, the outer diameter of tube 106 can be configured to substantially fill the lumen of catheter 101. As used herein, "fill" means that the outer diameter of tube 106 extends substantially across the inner diameter of lumen 111 of catheter 101. In some embodiments, tube 106 fills at least about 50%, 60%, 70%, 80%, 90%, or more of the lumen of the catheter.

[0145] The tube 106 can have a relatively thin sidewall thickness (e.g., 80 microns or less, 70 microns or less, 60 microns or less, or 50 microns or less, or between about 50 and 60 microns). The tube 106 can also have a relatively long overall length (e.g., 400 mm or more, 500 mm or more, 600 mm or more, 700 mm or more, 800 mm or more, between about 400 mm and 600 mm, or about 514 mm). Instead of or in addition to any one or combination of such dimensions, the tube 106 can have a relatively long cut length (the length of the portion of the tube 106 where the opening, void, convolution, or cutout 115 is present), the cut length being 400 mm or more, 500 mm or more, 600 mm or more, 700 mm or more, 800 mm or more, or about 514 mm.

[0146] A relatively long, small diameter and / or thin walled spiral cutting tube provides certain advantages for use in core assembly 103 in narrow and / or tortuous vasculature (e.g., neurovasculature). If desired, tube 106 can be made highly flexible (or flexible as the case may be) by using an appropriate spiral pitch, and the column strength or "pushability" of tube 106 can be maintained largely independent of its flexibility because the diameter of tube 106 can remain constant along its length. The combination of high flexibility and pushability can help to more easily navigate difficult tortuous vascular locations.

[0147] In various embodiments of the tube 106, the spiral or spiral cut 115 can be relatively long and continuous. For example, the tube 106 can have such a spiral or spiral cut 115 on any of the various cut lengths specified above or elsewhere herein of the tube 106. The tube 106 having such a spiral or spiral cut 115 can also have any one or combination of the various outer diameters, sidewall thicknesses, and / or total lengths specified above or elsewhere herein for the tube 106. The spiral or spiral cut can extend along the total length or nearly the total length of the tube (e.g., the total length except for a small uncut portion at the distal and / or proximal end), as shown in FIG. 2 with respect to the distal end of the spiral cut terminating in the stress relief hole.

[0148] A variety of techniques may be used to achieve long, continuous or helical or spiral cuts 115. In one approach, two or more longitudinally adjacent spirals, cuts, slits or voids may be formed in a continuous or helical relationship in the sidewall of the tube 106 and connected at their adjacent ends by connecting holes to form a continuous or helical or spiral cut, slit or void along the total length of the tube 106 or along the length of the cut. In some embodiments, the length of each spiral, cut, slit or void may be about 150 mm, or 150 mm or less in length. These need not be uniform along the length of the tube or the length of the cut; for example, the first or last spiral, cut, slit or void may be made slightly shorter to achieve a cut length that is not an even multiple of the length of a single spiral.

[0149] In some embodiments, one or more terminal holes may be employed in the cut, slit, or void of the spiral or helix. In other embodiments of the tube 106, a spiral or helix cut, slit, or void is employed with one or more terminal holes at one or both ends and no connecting holes along the length of the cut. One or more such spirals may be formed in the sidewall of a single tube 106. Where employed, the one or more terminal holes may serve as stress relief or prevent sidewall crack formation at one or more ends of the spiral.

[0150] In lieu of or in addition to spiral cuts 115 that are successive or continuous over a relatively long total length or cut length of the tube 106, the pitch of the spiral portion can be precisely controlled over the longer total length or cut length. For example, the pitch of the spiral cuts 115 can vary over the cut length so that a pitch of a particular size can dominate along a relatively short segment of the cut length, such as 5 mm or less, 3 mm or less, 2 mm or less, or about 1.0 mm. In this way, the spiral pitch can be finely adjusted in small increments of the cut length, thereby facilitating excellent control of the mechanical properties (e.g., bending stiffness, column strength) of the tube 106 in various portions of the tube. Thus, the tube 106 can have a pitch that varies in size along the total length or cut length of the tube (including a particular "first pitch size"), and the first pitch size can dominate over a first segment of the cut length. The length of the first segment (measured along the longitudinal dimension of the tube 106) can be 5 mm or less, 3 mm or less, 2 mm or less, or about 1.0 mm. The size of the pitch can vary from the first size at one or both ends of the first segment. The first segment can be located anywhere along the length of the cut (e.g., in a continuous or consecutive gap), including relatively far from the end of the length of the cut, for example, greater than 100 mm, greater than 200 mm, or greater than 300 mm from the end of the length of the cut.

[0151] Instead of or in addition to achieving a particular pitch size in one or more short segments of the cut length (and / or contiguous or continuous convolutions over a relatively long overall length or cut length of the tube 106), the pitch amplitude can be precisely controlled and therefore can be varied in relatively small increments. (The pitch can be expressed in mm / rev.) For example, the pitch can vary in size by 0.2 mm / rev or less, 0.1 mm / rev or less, 0.01 mm / rev or less, or 0.005 mm / rev or less. This provides another way in which the convolutions can be finely controlled to facilitate desired mechanical properties of various portions of the tube 106. Thus, the tube 106 can have a pitch that varies in size along the overall length or cut length of the tube (including a particular "first pitch size"), and the first pitch size can predominate over a first segment of the cut length. At one or both ends of the first segment, the size of the pitch may vary from the first size by 0.2 mm / revolution or less, 0.1 mm / revolution or less, 0.01 mm / revolution or less, or 0.005 mm / revolution or less. The first segment may be located anywhere along the length of the cut (e.g., in a continuous or consecutive gap), including a relatively distant position relative to the end point of the cut length, for example, greater than 100 mm, or greater than 200 mm, or greater than 300 mm from the end point of the cut length.

[0152] As described in more detail below, the tube 106 can be mounted on the wire 104 so that the tube 106 is fixed to the wire 104. For example, the tube 106 can be fixed to the wire 104 at one or more contact points. In one embodiment, the tube 106 is fixed to the wire 104 at one or more contact points in the proximal portion 116 of the tube 106 and at one or more contact points in the distal portion 118 of the tube. The tube 106 can be fixed to the wire 104 at these contact points by brazing, welding, adhesives, or other suitable fixing techniques. In some embodiments, there can be two, three, four, or more contact points at which the tube 106 is fixed to the wire 104. In other embodiments, the tube 106 can be fixed to the wire 104 at only a single contact point. In other embodiments, the tube 106 may not be fixed to the wire 104. As used herein, "fixation" includes direct and indirect fixation, for example, the wire 104 can be directly welded or adhered to the tube 106 at the contact point, or the tube can be welded or otherwise attached to an intervening member (e.g., the proximal restraint 119), which in turn is directly fixed to the wire 104.

[0153] During operation of the delivery system 100, securing portions of the tube 106 to the wire 104 can reduce or eliminate elongation or compression of the tube 106. As described above, the relatively large diameter of the tube 106 can enhance the pushability of the core assembly 103. However, the presence of the flexibility enhancing cutouts (e.g., the spiral cutouts 115 extending along the length of the tube) can cause the tube 106 to elongate or compress during movement of the core assembly 103 relative to the catheter 101. For example, during distal advancement of the core assembly 103, the distal portion 118 of the tube 106 can resist movement more than the proximal portion 116 of the tube 106 (e.g., due to frictional engagement with the inner wall of the catheter 101). As a result, the proximal portion 116 and the distal portion 118 will move closer to each other, resulting in compression of the tube 106 and a reduction in overall length. If, on the contrary, the distal portion 118 of the tube 106 resists proximal movement to a greater extent than the proximal portion 116, the proximal portion 116 and the distal portion 118 will move further, causing the tube 106 to elongate and its overall length to increase. Both elongation and compression may adversely change the performance characteristics of the tube 106, and thus change the performance characteristics of the core assembly 103. For example, elongation or compression can change the flexibility, column strength and navigability of the core assembly 103. By fixing the tube 106 to the wire 104 below at one or more contact points, the risk of the tube 106 being compressed or elongated can be reduced. In some embodiments, the proximal and distal ends of the tube 106 can be attached to the wire 104, thereby effectively fixing the overall length of the tube 106, and substantially eliminating the compression or elongation of the tube 106 during the operation of the delivery system 100. In other embodiments, the tube 106 can be fixed to the wire 104 at contact points spaced apart from the proximal and distal ends of the tube 106.

[0154] The system 100 may also include a coupling assembly 120 or a re-sheathing assembly 120 configured to releasably retain a medical device or stent 105 relative to the core assembly 103. The coupling assembly 120 may be configured to engage the stent 105 by mechanical interlocking with the holes and filaments of the stent 105, abutting the proximal side or edge of the stent 105, frictional engagement with the inner wall of the stent 105, or any combination of these modes of action. Thus, the coupling assembly 120 may cooperate with the overlying inner surface of the catheter 101 to grasp and / or abut the stent 105, such that the coupling assembly 120 may move the stent 105 along and within the catheter 101, e.g., distal and / or proximal movement of the core assembly 103 relative to the catheter 101 causes corresponding distal and / or proximal movement of the stent 105 within the catheter lumen 111.

[0155] In some embodiments, the coupling assembly 120 (or one or more portions thereof) can be configured to rotate about the core assembly 103. In some such embodiments, the coupling assembly 120 can include a proximal bumper or restraint 119 and a distal restraint 121. The proximal restraint 119 and the distal restraint 121 can be secured to the core assembly 103 to prevent or limit proximal or distal movement of the coupling assembly 120 along the longitudinal dimension of the core assembly 103. For example, the proximal restraint 119 and the distal restraint 121 can be welded or secured to the core wire 104 with an adhesive. The outer diameter or other radially outermost dimension of one or both of the proximal restraint 119 and the distal restraint 121 can be smaller than the outer diameter or other radially outermost dimension of the overall coupling assembly 120, such that during operation of the system 100, one or both of the restraints 119, 121 do not contact the inner surface of the stent 105. In some embodiments, the proximal restraint 119 can be sized to abut the proximal end of the stent 105 and to push the stent distally during delivery.

[0156] The coupling assembly 120 may also include first and second stent engagement members (or device engagement members or re-sheathing members) 123a-b (collectively referred to as "engagement members 123") and first and second spacers 125a-b (collectively referred to as "spacers 125") disposed about the core assembly 103 between the proximal constraint 119 and the distal constraint 121. In the illustrated embodiment, from proximal to distal, the elements of the coupling assembly 120 include the proximal constraint 119, followed by the first spacer 125a, the first stent engagement member 123a, the second spacer 125b, the second stent engagement member 123b, and finally the distal constraint 121. In this configuration, the first spacer 125a defines the relative positioning of the first engagement member 123a and the proximal constraint 119. The second spacer 125b defines the relative longitudinal pitch between the first engagement member 123a and the second engagement member 123b.

[0157] As described in more detail below, one or two of the spacers 125 can take the form of a coil, solid tube, or other structural element that can be mounted above the core assembly 103 to longitudinally separate adjacent components of the coupling assembly 120. In some embodiments, one or two of the spacers 125 can be a zero-pitch coil with flat ends. In some embodiments, one or two of the spacers 125 can be a solid tube (e.g., a laser cut tube) that is rotatably mounted or non-rotatably fixed (e.g., welded) to the core assembly 103. The radially outermost dimension of the spacer 125 can be smaller than the radially outermost dimension of the engagement member 123, so that the spacer 125 does not contact the stent 105 during normal operation of the system 100. As described in more detail below, the size, construction, and configuration of the spacer 125 can be selected to improve the grip between the coupling assembly 120 and the overlying stent 105.

[0158] The stent 105 can be moved distally or proximally within the overlying catheter 101 via the proximal coupling assembly 120. In some embodiments, after the stent 105 is partially deployed from the distal opening of the catheter, the stent 105 can be re-sheathed via the proximal coupling assembly 120. In embodiments where the proximal restraint 119 is sized to abut the proximal end of the stent 105 and is used to push the stent distally during delivery, after partial deployment, the first and second stent engagement members 123a-b can be used to re-sheath the stent 105 without participating (or substantially participating) in pushing the stent distally during delivery. For example, in such an embodiment, the first and second stent engagement members 123a-b can transmit no or almost no thrust to the distal stent 105 during delivery.

[0159] Optionally, when in the delivery configuration, the proximal edge of the proximal coupling assembly 120 can be positioned just distal to the proximal edge of the stent 105. In some such embodiments, this enables re-sheathing of the stent 105 when as little as a few millimeters of the stent remains in the catheter. Thus, for stents of typical lengths, 75% or more re-sheathability can be provided (i.e., the stent can be re-sheathed when the stent has been deployed 75% or more).

[0160] Continue to refer Figure 1, the distal interface assembly 122 can include a distal engagement member 124 that can take the form of, for example, a distal device cover or a distal stent cover (generally, a "distal cover"). The distal cover 124 can be configured to reduce friction between the stent 105 (e.g., a distal portion thereof) and the inner surface of the surrounding catheter 101. For example, the distal cover 124 can be configured as a lubricated, flexible structure having a free first end or section 124a that can extend over at least a portion of the stent 105 and / or the intermediate portion 108 of the core assembly 103, and a fixed second end or section 124b that can be coupled (directly or indirectly) to the core assembly 103.

[0161] The distal covering 124 can have a first or delivery position, configuration, or orientation, wherein the distal covering can extend proximally relative to the distal tip, or proximally from the second section 124b or its (direct or indirect) attachment to the core assembly 103, and at least partially surround or cover a distal portion of the stent 105. The distal covering 124 can be moved from the first or delivery orientation to a second or re-sheathing position, configuration, or orientation (not shown), wherein the distal covering can be everted such that the first end 124a of the distal covering is positioned distally relative to the second end 124b of the distal covering 124 to enable the core assembly 103 to be re-sheathed with or without the stent 105 carried thereby. Figure 1 As shown, the first section 124a of the distal cover 124 can originate from the proximal end of the second section 124b. In another embodiment, the first section 124a can originate from the distal end of the second section 124b.

[0162] Lubricating and / or hydrophilic materials (such as PTFE or ) to make the distal cover 124, but the distal cover can be made of other suitable lubricating materials or lubricating polymers. The distal cover can also include a radiopaque material that can be mixed into the main material (e.g., PTFE) to impart radiopacity. The thickness of the distal cover 124 can be between about 0.0005" and about 0.003". In some embodiments, the distal cover can be one or more PTFE strips having a thickness of about 0.001".

[0163] The distal cover 124 (e.g., the second end 124b thereof) can be fixed to the core assembly 103 (e.g., to the wire 104 or its distal tip) in a longitudinal / sliding manner or a radial / rotational manner so as to be immovable relative to the core assembly 103. Alternatively, as Figure 1As depicted, the distal cover 124 (e.g., the second end 124b thereof) can be coupled to (e.g., mounted on) the core assembly 103 such that the distal cover 124 can rotate about the longitudinal axis of the core assembly 103 (e.g., of the wire 104) and / or move or slide longitudinally along the core assembly 103. In such an embodiment, the second end 124b can have an inner cavity for receiving the core assembly 103 therein so that the distal cover 124 can slide and / or rotate relative to the core assembly 103. Additionally, in such an embodiment, the distal interface assembly 122 can also include a proximal restraint 126 and / or a distal restraint 128, the proximal restraint being fixed to the core assembly 103 and positioned proximal to the distal cover 124 (the second end 124b), the distal restraint being fixed to the core assembly 103 and positioned distal to the distal cover 124 (the second end 124b). The distal interface assembly 122 can include a radial gap between an outer surface of the core assembly 103 (e.g., of the wire 104) and an inner surface of the second end 124b. Such a radial gap can be formed when the second end 124b is configured to have a lumen diameter that is slightly larger than the outer diameter of a corresponding portion of the core assembly 103. When the radial gap exists, the radial gap allows the distal cover 124 and / or the second end 124b to rotate about the longitudinal axis of the core assembly 103 between the constraints 126, 128.

[0164] In some embodiments, the outer diameter or other radially outermost dimension of one or both of the proximal and distal restraints 126, 128 can be smaller than the (e.g., pre-deployment) outer diameter or other radially outermost dimension of the distal cover 124, such that one or both of the restraints 126, 128 do not tend to abut or contact the inner surface of the catheter during operation of the core assembly 103. Alternatively, it may be preferable to have the outer diameter of the restraints 126 and 128 larger than the maximum radial dimension of the distal cover 124 before deployment, and / or to have the outer diameter of the proximal restraint 126 larger than the outer diameter of the distal restraint 128. This configuration allows for easy and smooth retraction of the distal cover 124 and restraints 126, 128 into the catheter after stent deployment.

[0165] In operation, when the stent 105 is moved distally through the surrounding catheter, the distal cover 124, and in particular the first section 124a, can generally cover and protect the distal portion of the stent 105. The distal cover 124 can act as a support or buffer layer that, for example, inhibits the filament ends of the distal portion of the stent 105 (wherein the stent includes a braided stent) from contacting the inner surface of the catheter, which may damage the stent 105 and / or the catheter, or otherwise compromise the structural integrity of the stent 105. Since the distal cover 124 can be made of a lubricating material, the distal cover 124 can exhibit a low friction coefficient that allows the distal portion of the stent to slide axially in the catheter relatively easily. The friction coefficient between the distal cover 124 and the inner surface of the catheter 101 can be between about 0.02 and about 0.4. For example, in an embodiment in which the distal cover and the catheter are formed of PTFE, the friction coefficient can be about 0.04. Such an embodiment can advantageously improve the ability of the core assembly 103 to pass through the catheter, especially in a curved vascular system.

[0166] Structures other than the embodiments of the distal covering 124 described herein may be used in the core assembly 103 and / or the distal interface assembly 122 to cover the distal region of the stent 105 or otherwise connect to the distal region of the stent. For example, a protective coil or other sleeve having a longitudinally oriented, proximally open cavity may be employed. In other embodiments, the distal interface assembly 122 may omit the distal covering 124, or the distal covering may be replaced with an assembly similar to the proximal coupling assembly 120. Where the distal covering 124 is employed, the distal covering may be connected to the distal tip coil 112 (e.g., by encircling and surrounding some or all of the windings of the coil 112) or attached to or connected to the outer surface of the coil by an adhesive or surrounding shrink tubing. The distal covering 124 may be coupled (directly or indirectly) to other portions of the core assembly 103, such as the wire 104.

[0167] In an embodiment of the core assembly 103 that employs both a rotatable proximal coupling assembly 120 and a rotatable distal cover 124, the stent 105 can be rotatable relative to the core member about the longitudinal axis of the core assembly 103 by means of the rotatable connection of the proximal coupling assembly 120 and the distal cover 124. In such an embodiment, the stent 105, the proximal coupling assembly 120, and the distal cover 124 can rotate together about the core assembly 103 in this manner. When the stent 105 can rotate about the core assembly 103, the core assembly 103 can be more easily advanced through a tortuous vessel because the tendency of the vessel to twist the stent 105 and / or the core assembly 103 is eliminated by the rotation of the stent 105, the proximal coupling assembly 120, and the distal cover 124 about the core assembly 103. In addition, because the user's input thrust is not transferred into the torsion of the stent 105 and / or the core assembly 103, the required thrust or delivery force is reduced. The tendency of a twisted stent 105 and / or core assembly 103 to suddenly untwist or "whip" when exiting the bend or deployment of the stent 105 is also reduced or eliminated, as well as the tendency of a twisted stent to resist expansion when deployed. Further, in some such embodiments of the core assembly 103, a user can "steer" the core assembly 103 via the tip coil 112, particularly if the coil 112 is bent at an angle in its unstressed configuration. Such a coil tip can be rotated about the longitudinal axis of the system 100 relative to the stent 105, the coupling assembly 120, and / or the distal cover 124 by rotating the distal portion 110 of the core assembly 103. Thus, a user can point the coil tip 112 in the desired direction of travel of the core assembly 103, and as the core assembly is advanced, the tip will guide the core assembly in the selected direction.

[0168] Figure 2A yes Figure 1 A side view of the core assembly 103 of the medical device delivery system 100 is shown, and Figure 2B yes Figure 2A 2B-2B of a cross-sectional side view of a core assembly 103 of FIG. As described above, the core assembly 103 includes an elongated shaft or wire 104 and a tube 106 extending longitudinally around the wire 104 along at least a portion of the length of the wire 104. The wire 104 includes a proximal portion 108, a distal portion 110, and a middle portion 114, the middle portion being configured to carry a stent 105 ( Figure 1 ). Tube 106 is disposed over wire 104 such that wire 104 extends through the lumen of tube 106. The length of wire 104 may be greater than the length of tube 106 such that wire 104 extends proximally of a proximal portion 116 of tube 106 and also extends distally of a distal portion 118 of tube 106.

[0169] As described above, the tube 106 can have a spiral or helical void or cutout 115 extending along at least a portion of the length of the tube 106, and the cutout 115 can include one or more segments 115a, 115b having different pitch sizes to impart different bending stiffnesses to the tube 106 along different portions of its length. The cutout 115 can terminate in a hole 232 formed in the sidewall of the tube 106. The hole 232 can include additional voids formed in the sidewall of the tube 106 (e.g., cutouts) and connected or continuous with the void or cutout 115. Figure 2A As shown, the hole 232 may include a circle or any other suitable shape, such as an ellipse or a polygon. When used, the hole 232 may be used as a stress relief or to measure the sidewall crack formation at the end of the spiral cut 115. In some embodiments, different sections of the cut 115 (e.g., the first section 115a and the second section 115b) may be connected by connecting holes to form a single, continuous or continuous void. The connecting holes may be substantially similar to the holes 232, except that they are located between adjacent sections of the cut 115 (e.g., between the first section 115a and the second section 115b).

[0170] The wire 104 can have an outer profile that tapers radially inward in the distal direction, with a larger outer profile (e.g., diameter) at the proximal portion 108 and a smaller outer profile at the distal portion 110. The taper can be gradual and continuous along the length of the wire 104, or in some embodiments, the taper can vary at different portions of the wire 104. Figure 2A and Figure 2B In the illustrated embodiment, the wire 104 can include two (or more) constant diameter sections: a first constant diameter section 234 and a second constant diameter section 236. The wire 104 can have a substantially uniform (i.e., non-tapered) outer profile on each of these sections 234, 236. The first constant diameter section 234 can be positioned below the proximal portion 116 of the tube 106, and the second constant diameter section 236 can be positioned below the distal portion 118 of the tube 106. Because the wire 104 tapers distally from the first constant diameter section 234 to the second constant diameter section 236, in some embodiments, the outer profile (e.g., diameter) of the first constant diameter section 234 is greater than the outer profile (e.g., diameter) of the second constant diameter section 236. In some embodiments, the length of the first constant diameter section 234 can be between about 1" to 8", 2" to 6", 3" to 5", or about 4". In some embodiments, the length of the second constant diameter section 236 can also be between about 1" to 8", 2" to 6", 3" to 5", or about 4".

[0171] These first and second constant diameter sections 234 and 236 can provide portions of the wire 104 that are configured to be secured to corresponding portions of the surrounding tube 106. The tube 106 can be secured to the wire 104 at a first contact point 238 at the proximal portion 116 of the tube 106, and can also be secured to the wire 104 at a second contact point 240 at the distal portion 118 of the tube 106. The first contact point 238 can be positioned at any longitudinal position within the first constant diameter section 234, and the second contact point 240 can be positioned at any longitudinal position within the second constant diameter section 236. Thus, the first and second constant diameter sections 234, 236 enable the wire 104 to accommodate the first and second contact points 238, 240 within a range of different longitudinal positions within the first and second constant diameter sections 234, 236, respectively. For example, in various embodiments, the first contact point 238 can be positioned at any longitudinal position along the length of the first constant diameter section 234, and the second contact point 240 can be positioned at any longitudinal position along the length of the second constant diameter section 236.

[0172] For combining different lengths of tubes 106 and / or brackets 105 ( Figure 1 ) of the wire 104, this feature may be useful. For example, the middle portion 114 of the wire 104 can accommodate stents with a range of different stent sizes. In the case of a longer stent, the proximal end of the stent can extend proximally along the wire compared to a shorter stent. In order to position the proximal buffer or restraint 119 adjacent to the proximal end of the stent, the restraint 119 can be placed at different longitudinal positions along the second constant diameter section 236 depending on the length and position of the stent. For a shorter stent, the restraint 119 (together with the distal portion 118 of the tube 106) will be positioned more distally than a longer stent. By moving the restraint 119 and the distal portion 118 of the tube 106 along the second constant diameter section 236, the proximal portion 116 of the tube 106 is also moved an equal amount along the first constant diameter section 234. Therefore, the lengths of the first and second constant diameter sections 234, 236 can provide a range of longitudinal positions on which the first and second contact points 238, 240 can be located.

[0173] The wire 104 and the tube 106 can be configured such that during operation of the delivery system, the tubing 106 bends preferentially before the wire 104. For example, the sidewall thickness, material cross-section, and spiral cut 115 of the tube 106 can all be varied to provide a desired bending stiffness at different portions along the length of the tube 106. Likewise, the material and dimensions of the wire 104 can vary along the length of the wire 104 to provide a varying bending stiffness along its length. The relative bending stiffness of the wire 104 and the tube 106 can be configured such that when the core assembly 103 is bent (e.g., during a curved anatomical structure), the tube 106 bends before the wire 104. This allows the strain to be borne primarily by the tube 106, which can reduce the load borne by the wire 104 and reduce the required delivery force.

[0174] As described above, the tube 106 may be secured to the wire 104 along the first constant diameter section 234 at the first contact point 238. Figure 5 106 , the first contact point 238 can be at the proximal end of the tube 106. The wire 104 can be secured to the tube 106 at the first contact point 238 by welding, brazing, adhesive, or any other suitable securing technique. The outer profile (e.g., diameter) of the wire 104 can be configured to facilitate securing the wire 104 to the tube 106 at the first contact point 238. For example, in some embodiments, the outer profile of the wire 104 is nearly as large as the inner profile of the lumen of the tube 106, such that the wire 104 substantially fills the lumen of the tube 106 at the first contact point 238. This can facilitate welding, brazing, or otherwise securing or attaching the wire 104 to the tube 106. Since the outer profile of the tube 106 can be substantially constant along the first constant diameter section 234, the tube 106 can be secured to the wire 104 at the first contact point 238 at any point along the length of the first constant diameter section 234.

[0175] The tube 106 may be secured to the restraint 119 along the second constant diameter section 236 at the second contact point 240. Figure 3 and Figure 4 , a proximal bumper or restraint 119 can be mounted above the wire 104 at a longitudinal position within the second constant diameter section 236 of the wire 104. The restraint 119 includes an internal cavity 441 configured to receive the wire 104 therethrough. The cavity 441 can be sized to correspond to the outer profile (e.g., diameter) of the wire 104 along the second constant diameter section 236. In some embodiments, the restraint 119 is welded, soldered, or otherwise fixed relative to the wire 104 so that it cannot rotate or translate relative to the wire 104. In other embodiments, the restraint 119 can be configured to allow rotation and / or translation relative to the wire 104 within a predetermined range.

[0176] The constraint 119 also includes a distal section 442 having a first outer profile and a proximal section 444 having a second outer profile that is smaller than the first outer profile. The outer profile of the proximal section 444 can be sized and configured to fit within the lumen of the tube 106, while the outer profile of the distal section 442 can be sized and configured to abut against the distal end of the tube 106. In some embodiments, the outer profile of the distal section 442 matches or exceeds the outer profile of the tube 106 so that the distal portion 118 of the tube 106 cannot move distally beyond the distal section 442 of the constraint 119. When the tube 106 is positioned on the proximal section 444 of the constraint 119 (e.g., Figure 3 ), the proximal section 444 can partially overlap the hole 232 in the sidewall of the tube 106. In some embodiments, the proximal section 444 does not overlap the hole 232 by more than 30%, more than 40%, more than 50%, more than 60%, or more than 70%. In some embodiments, the proximal section 444 does not overlap the hole 232 at all.

[0177] The tube 106 may be secured to the restraint 119 at the second contact point 240 by welding, brazing, adhesive, or any other suitable securing technique. The outer profile (e.g., diameter) of the restraint 119 may be configured to facilitate securing the restraint 119 to the tube 106 at the second contact point 240. For example, in some embodiments, the outer profile of the proximal section 444 of the restraint 119 is nearly as large as the inner profile of the lumen of the tube 106, such that the proximal section 444 of the restraint 119 substantially fills the lumen of the tube 106 at the second contact point 240. This may facilitate welding, brazing, or otherwise securing or attaching the restraint 119 to the tube 106.

[0178] In some embodiments, the tube 106 can be directly fixed to the wire 104 at the second contact point 240, such as by welding, brazing, adhesives, or other fixing techniques. In some embodiments, instead of the restraint 119, the tube 106 can be connected to another intermediate member, which in turn is attached to the wire 104. For example, an attachment member separate from the restraint 119 can be attached to the wire 104, and the tube 106 can in turn be attached to the attachment member at the second contact point 240.

[0179] In some embodiments, the wire 104 may include only the first constant diameter section 234 and omit the second constant diameter section 236, while in other embodiments, the wire 104 may include only the second constant diameter section 236 and omit the first constant diameter section. In other embodiments, the wire 104 may omit the first and second constant diameter sections 234, 236 and have a tapered or otherwise varying outer profile in those sections of the wire 104.

[0180] Although the first contact point 238 and the second contact point 240 are shown as being at or near the proximal and distal ends of the tube 106, in some embodiments, one or more of the first and second contact points can be located at locations spaced apart from the proximal and distal ends of the tube 106. Additionally or alternatively, in some embodiments, additional contact points at other longitudinal locations along the wire can be present. For example, an additional contact point can be provided between the first and second contact points to provide another fixation point between the tube and the wire and further prevent compression or elongation of the tube relative to the wire.

[0181] Fig. 6A and Figure 6B is a graph of bending stiffness of components of a medical device delivery system according to some embodiments. Fig. 6A , line 601 depicts the bending stiffness of a hypotube as a function of distance from its distal end. The bending stiffness generally increases in the proximal direction such that the distal-most portion (on the left side of the figure) has the lowest bending stiffness and the proximal-most portion (on the right side of the figure) has the highest bending stiffness. The bending stiffness can increase in a series of step changes. Line 603 depicts the bending stiffness of a catheter configured to receive a hypotube passing therethrough. Like the hypotube, the bending stiffness of the catheter increases with distance from the distal end. However, the increase in bending stiffness of the catheter over its total length is less. Line 605 depicts the difference in bending stiffness at each point between the hypotube and the catheter, expressed as a percentage. A high mismatch between the bending stiffness of the catheter and the hypotube can result in increased kinking of the catheter, particularly when navigating curved anatomical structures such as the neurovasculature. As Fig. 6A As shown, line 605 increases significantly between 5 and 15 inches, reflecting the large difference in bending stiffness between the catheter and the hypotube over this length range. Disadvantageously, this can lead to kinks or other snags, which can increase the total delivery force required to pass the core or hypotube through the catheter.

[0182] To ameliorate these problems, the bending stiffness of the hypotube and / or catheter may be modified to reduce the difference between at least a portion of their lengths. Figure 6B shows the bending stiffness of the components of the delivery system, where Fig. 6A The hypotube has been modified to have reduced bending stiffness in the 5 to 15 inch range compared to the hypotube of the 1980s. Figure 6B , line 603 again reflects the bending stiffness of the catheter, which is relative to Fig. 6A No change. Line 607 depicts the bending stiffness of the hypotube relative to Fig. 6A The range of 5 to 15 inches is reduced. Line 609 depicts the percentage difference in bending stiffness between the hypotube and the conduit. Figure 6B As seen in FIG. 6 , line 609 remains low in the 5 to 15 inch range, consistent with Fig. 6A The comparison reflects the similar bending stiffness of the hypotube and conduit in this range. Therefore, by reducing the bending stiffness of the tube in the range of 5 to 15 inches, the bending stiffness of the hypotube is closer to the bending stiffness of the conduit. Fig. 6A and 6B The design shown was evaluated for delivery and sheath forces and found to be Fig. 6A Compared with the design of Figure 6B The design resulted in a 21% reduction in delivery force and a 32% reduction in sheath force. This suggests that the performance of the delivery system may be improved by more closely matching the bending stiffness of the catheter to that of the hypotube along at least a portion of the curved length of the catheter.

[0183] To more closely match the bending stiffness of the tube to that of the catheter, the tube can be configured to have a bending stiffness that is less than 500%, 400%, 300%, or 200% of the bending stiffness of the catheter along at least the distal portion of the tube. In some embodiments, the distal portion of the hypotube spans at least 5 inches, at least 10 inches, at least 15 inches, at least 20 inches, at least 25 inches, or at least 30 inches from the distal end of the hypotube.

[0184] in conclusion

[0185] The present disclosure is not intended to be exhaustive or to limit the present invention to the precise form disclosed herein. Although specific embodiments are disclosed herein for the purpose of illustration, various equivalent modifications are possible without departing from the present invention as will be appreciated by those skilled in the relevant art. In some cases, known structures and functions have not yet been shown and / or described in detail to avoid unnecessarily obscuring the description of the embodiments of the present invention. Although the steps of the method can be presented in a particular order herein, in alternative embodiments, the steps can have another suitable order. Similarly, certain aspects of the present invention disclosed in the context of a particular embodiment can be combined or removed in other embodiments. In addition, although the advantages associated with those embodiments have been disclosed in the context of certain embodiments, other embodiments can also exhibit these advantages, and not all embodiments must exhibit such advantages or other advantages disclosed herein to fall within the scope of the present invention. Therefore, the present disclosure and associated technology can cover other embodiments that are not explicitly shown and / or described herein.

[0186] Throughout this disclosure, unless the context clearly indicates otherwise, the singular terms "a", "an" and "the" include plural references. Similarly, unless the word "or" is explicitly limited to mean only a single item other than other items in a list with two or more items, the use of "or" in such a list should be interpreted as including: (a) any single item in the list, (b) all items in the list, or (c) any combination of items in the list. In addition, the term "including" and the like are used throughout this disclosure to mean at least including one or more of the listed features, so that any greater number of one or more identical features and / or one or more other types of features are not excluded. Directional terms such as "upper", "lower", "front", "back", "vertical" and "horizontal" can be used in this article to express and clarify the relationship between the various elements. It should be understood that such terms do not represent absolute orientation. References to "an embodiment", "embodiment" or similar expressions herein mean that specific features, structures, operations or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present invention. Therefore, the appearance of such phrases or expressions in this article does not necessarily all refer to the same embodiment. Furthermore, the particular features, structures, operations, or characteristics may be combined in any suitable manner in one or more embodiments.

Claims

1. A stent delivery system, comprising: A core assembly sized for insertion into a body lumen, the core assembly configured to advance a stent toward a treatment location in the body lumen, the core assembly comprising: a longitudinally extending tube having a lumen and a helical cut extending along the tube; and an elongated solid wire extending through the entire length of the lumen of the tube, the wire having an intermediate portion disposed distally of the tube, wherein a proximal portion of the tube is fixed in a proximal position relative to the wire, and a distal portion of the tube is fixed in a distal position relative to the wire, thereby limiting compression or elongation of the tube; and a support, the support being carried by the intermediate portion, wherein the tube is configured to bend preferentially before the wire bends, Wherein the relative bending stiffnesses of the wire and the tube are configured such that the tube bends before the wire.

2. The system according to claim 1, wherein: The wire extends proximate the proximal end of the tube.

3. The system according to claim 1, wherein: A proximal portion of the tube is welded to the wire.

4. The system according to claim 1, wherein: A restraint is coupled to the wire, and wherein a distal portion of the tube is welded to the restraint.

5. The system according to claim 1, wherein: The system also includes a catheter having a lumen configured to receive the core assembly therethrough.

6. The system according to claim 5, wherein: The tube is sized to fill the lumen of the catheter.

7. The system according to claim 1, wherein: The diameter of the wire tapers distally toward the distal end of the wire.

8. The system of claim 1, further comprising a catheter configured to receive the core assembly therethrough, and wherein: The bending stiffness of the tube is configured to match the bending stiffness of the catheter.

9. The system of claim 1, further comprising a catheter configured to receive the core assembly therethrough, wherein: At least along a distal portion of the tube, the tube has a bending stiffness that is less than 300% of a bending stiffness of the catheter.

10. The system according to claim 1, wherein: The bending stiffness of the core assembly is adjusted by the pitch of the spiral cuts.

11. A core assembly sized for insertion into a body lumen, the core assembly configured to advance a stent toward a treatment location in the body lumen, the core assembly comprising: a hypotube having a proximal end, a distal end, a lumen, and a helical cutout extending along the hypotube; and an elongated solid wire extending completely through the lumen of the hypotube, the wire having a distal portion extending distally beyond the lumen of the hypotube, wherein a proximal portion of the hypotube is fixed in a proximal position relative to the wire and a distal portion of the hypotube is fixed in a distal position relative to the wire, thereby limiting compression or elongation of the tube, wherein the hypotube is configured to bend preferentially before the wire bends, Wherein the relative bending stiffnesses of the wire and the tube are configured such that the tube bends before the wire.

12. The core assembly of claim 11, wherein: The system also includes a catheter having a lumen configured to receive the core assembly therethrough.

13. The core assembly of claim 12, wherein: The hypotube is sized to fill the lumen of the catheter.

14. The core assembly of claim 11, further comprising a conduit configured to receive the core assembly therethrough, and wherein: The bending stiffness of the hypotube is configured to match the bending stiffness of the catheter.

15. The core assembly of claim 11, further comprising a conduit configured to receive the core assembly therethrough, wherein: At least along a distal portion of the hypotube, the bending stiffness of the hypotube is less than 300% of the bending stiffness of the catheter.

16. The core assembly of claim 15, wherein: The distal portion of the hypotube spans at least 15 inches from the distal end of the hypotube.

17. The core assembly of claim 15, wherein: The distal portion of the hypotube spans at least 30 inches from the distal end of the hypotube.

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