WO2018005473A1

WO2018005473A1 - Delivery systems for endovascular devices and related methods

Info

Publication number: WO2018005473A1
Application number: PCT/US2017/039478
Authority: WO
Inventors: Vikas Gupta; Colin Kealey
Original assignee: Nsvascular, Inc.
Priority date: 2016-06-27
Filing date: 2017-06-27
Publication date: 2018-01-04
Also published as: GB2594425A; GB2567069A; GB2594425B; GB201820247D0; GB2567069B

Abstract

A delivery system includes a delivery braid, a delivery wire, a delivery tip, and a delivery sheath. The delivery braid is configured to be selectively inserted into a catheter. The delivery wire is configured to be inserted into the delivery braid and be selectively moveable along the delivery braid. The delivery tip is connected to the delivery wire and is configured to engage an endovascular device. The delivery sheath is connected to the delivery braid, and is configured to surround the endovascular device and be selectively inserted into the catheter to contact the endovascular device with its inner surface and contact the catheter with its outer surface. The delivery sheath may be composed of or include a low-friction such as polytetrafluoroethylene (PTFE) and thereby reduce friction between the catheter and the endovascular device covered with the delivery sheath.

Description

DELIVERY SYSTEMS FOR ENDOVASULAR DEVICES AND RELATED METHODS

Vikas Gupta and Colin Kealey

[0001] The present application claims the benefit of U.S. Provisional Application No. 62/355,275, filed on June 27, 2016, which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

[0002] The present disclosure generally relates to medical devices and, more particularly, to delivery systems for endovascular devices.

BACKGROUND

[0003] Endovascular devices must be compressed and inserted into small diameter catheters to be delivered via minimally-invasive means throughout the body. This can be difficult because endovascular devices may exert a radial force on the wall of the catheter and must be pushed through very tortuous anatomy. This can cause significant friction, limiting the ability of operators to efficiently deliver devices to the desired anatomical target. Common strategies to improve endovascular device delivery have focused on decreasing friction between the catheter wall and the device. This is commonly accomplished with low friction, hydrophilic, and lubricious inner linings of catheters (PTFE is commonly used for this purpose), as well as surface modifications of the device being delivered.

[0004] This problem is particularly acute for covered stents (e.g., thin-film covered stents) where there is a large amount of material that must be compressed into the catheter. The high amount of surface area of the stent covering increases the friction between the stent and catheter wall so that delivering covered stents can be more challenging than their non-covered counterparts.

[0005] Thus, there is a need for an improved delivery system for endovascular devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 illustrates a delivery system including a delivery sheath according to an embodiment of the present disclosure.

[0007] FIG. 2 illustrates a method of operating the delivery sheath of FIG. 1.

[0008] FIG. 3 illustrates an endovascular device assembled in a delivery system according to an embodiment of the present disclosure.

[0009] FIG. 4 illustrates an endovascular device being deployed from a delivery system at a target blood vessel according to an embodiment of the present disclosure.

[0010] FIG. 5 illustrates a delivery system including a delivery sheath with two longitudinal cuts and extending from a delivery braid according to an embodiment of the present disclosure.

[0011] FIG. 6 illustrates a delivery system including a delivery sheath with two longitudinal cuts and attached to a delivery braid using tubing according to an embodiment of the present disclosure.

[0012] FIG. 7 illustrates a delivery sheath with four longitudinal cuts.

[0013] FIG. 8 illustrates a delivery system including a delivery sheath with no longitudinal cuts and attached to a delivery braid using tubing according to an embodiment of the present disclosure.

[0014] FIG. 9 illustrates a delivery sheath formed from a hypotube according to an embodiment of the present disclosure.

[0015] FIGS. lOA-lOC illustrate a delivery sheath with a plurality of tips according to an embodiment of the present disclosure.

[0016] FIG. 11 illustrates a delivery sheath extending from a delivery braid according to an embodiment of the present disclosure.

[0017] FIG. 12A-B illustrate a delivery sheath with a flared portion extending from a delivery braid according to an embodiment of the present disclosure. [0018] FIG. 13A-B illustrates a delivery sheath with a uniform or relatively uniform diameter extending from a delivery braid according to an embodiment of the present disclosure.

[0019] FIG. 14 illustrates a delivery wire according to an embodiment of the present disclosure.

[0020] FIG. 15 illustrates a delivery tip according to an embodiment of the present disclosure.

[0021] FIG. 16 illustrates the delivery tip of FIG. 15 assembled on a delivery wire according to an embodiment of the present disclosure.

[0022] FIGS. 17A-B illustrate a two-piece delivery tip according to an embodiment of the present disclosure.

[0023] FIG. 18 illustrates the two-piece delivery tip of FIGS. 17A-B assembled on a delivery wire according to an embodiment of the present disclosure.

[0024] FIGS. 19A-B are images of a delivery tip and a delivery wire according to an embodiment of the present disclosure.

[0025] FIGS. 20A-B are images of a delivery sheath extending from a delivery braid and a delivery tip assembled on a delivery wire according to an embodiment of the present disclosure.

[0026] FIGS. 21A-B are images of an endovascular device before and after being assembled on a delivery tip according to an embodiment of the present disclosure.

[0027] FIGS. 22A-D are images of an endovascular device being inserted into a catheter according to an embodiment of the present disclosure.

[0028] FIGS. 23A-C are images of an endovascular device being deployed from a catheter according to an embodiment of the present disclosure.

[0029] Embodiments of the present disclosure and their advantages are best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures, in which the showings therein are for purposes of illustrating the embodiments and not for purposes of limiting them.

DETAILED DESCRIPTION

[0030] One or more embodiments of the present disclosure provide improved delivery systems for medical devices such as endovascular devices.

[0031] FIG. 1 is a diagrammatic side view of a delivery system 100. Delivery system 100 includes a delivery sheath 102 that is tubular and has a proximal end 104, a distal end 106, and forms a lumen therethrough. One or more longitudinal cuts 108 may be formed on delivery sheath 102. Delivery system 100 also includes a delivery braid 110, a delivery wire 112 disposed in delivery braid 110, a delivery tip 114 coupled with delivery wire 112. One or more holes or grooves 116 may be formed on delivery tip 114. Delivery system 100 may also include a delivery catheter 118, and delivery sheath 102, delivery braid 110, delivery wire 112, and/or delivery tip 114 may be placed in delivery catheter 118. An endovascular device 120 (e.g., a stent, a covered stent, a therapeutic delivery stent, or other endovascular device) may be assembled in delivery system 100.

[0032] Delivery sheath 102 is composed of or includes a low-friction material such as polytetrafluoroethylene (PTFE) (e.g., TEFLON®) or other low-friction material. Delivery sheath 102 has a thin wall with a thickness of, for example, less than approximately 0.005 inches, less than approximately 0.004 inches, less than approximately 0.003 inches, less than

approximately 0.002 inches, or less than approximately 0.001 inches. The thickness of the thin wall may be, for example, approximately 0.0001 inches, 0.0005 inches, 0.001 inches, 0.002 inches, 0.003 inches, 0.004 inches, or 0.005 inches, where any value can form an upper or a lower end point of a range for the thickness of the thin wall, as appropriate. The term

"approximately," as used herein when referring to a measurable value is meant to encompass variations of ±20 %, ±10 %, ±5 %, ±1 %, ±0.5 %, or ±0.1 % of the specified value. Delivery sheath 102 has an outer surface configured to contact the inner surface of delivery catheter 118 and an inner surface configured to contact endovascular device 120.

[0033] Delivery braid 110 is tubular and has a proximal end, a distal end coupled with delivery sheath 102, and a lumen extending therethrough. Delivery wire 112 is disposed in the lumen of delivery braid 110 and extends along the longitudinal length of delivery braid 110. Delivery wire 112 is configured to be selectively moved along delivery braid 110 in the longitudinal direction.

[0034] Delivery wire 112 is connected to delivery tip 114, which in turn is configured to be selectively coupled with a proximal end of endovascular device 120. When endovascular device 120 is placed in delivery system 100, endovascular device 120 is disposed in the lumen of delivery sheath 102, with the circumferential outer surface of endovascular device 120 contacting the inner surface of delivery sheath 102, and the proximate end of endovascular device 120 is coupled with delivery tip 114.

[0035] Delivery catheter 118 is tubular and has a proximal end, a distal end, and a lumen extending therethrough. Delivery catheter 118 is composed of or includes a low-friction material such as PTFE or other low-friction material. Delivery catheter 118 is configured to contain delivery sheath 102, endovascular device 120 disposed in delivery sheath 102, delivery braid 110, delivery wire 112 disposed in delivery braid 110. Delivery braid 110 is configured to be selectively moved relative to delivery catheter 118 in the longitudinal direction. Delivery sheath 102 is configured to be selectively and slidingly moved relative to delivery catheter 118 in the longitudinal direction.

[0036] FIG. 2 illustrates a method 200 of operating a delivery system such as delivery system 100 in FIG. 1. At block 202, endovascular device 120 is coupled with delivery wire 112 by coupling endovascular device 120 with delivery tip 114 (e.g., using holes or grooves 116) at the distal end of delivery wire 112. For example, solder bumps formed on endovascular device 120 may be engaged with holes or grooves 116. At block 204, endovascular device 120 is surrounded with delivery sheath 102. At block 206, delivery braid 110 and/or delivery wire 112 is pulled relative to delivery catheter 118, which in turn pulls endovascular device 120 covered by delivery sheath 102 into delivery catheter 118 to assemble endovascular device 120 in delivery system 100 as shown in FIG. 3.

[0037] To deploy endovascular device 120, at block 208, delivery braid 110 and/or delivery wire 112 is pushed relative to delivery catheter 118 in direction 122 as shown in FIG. 3 (also referred to as the direction of delivery force) to slidingly push delivery sheath 102 and endovascular device 120 along delivery catheter 118 and then out of delivery catheter 118 at a target blood vessel 124 of a patient as shown in FIG. 4. In some examples, delivery sheath 102 is expandable such that if endovascular device 120 is a self-expanding device, delivery sheath 102 radially expands with endovascular device 120 when it is pushed out of delivery catheter 118.

[0038] Because both delivery sheath 102 and delivery catheter 118 is composed of or include low-friction material, delivery sheath 102 may slidingly move relative to deliver}' catheter 118 with less friction compared to the friction between the inner surface of conventional catheters and endovascular devices. For example, both delivery sheath 102 and delivery catheter 118 may include PTFE resulting in a PTFE-to-PTFE contact that has very low friction.

Accordingly, the low friction between delivery sheath 102 and delivery catheter 118 facilitates pushing of endovascular device 120 through delivery catheter 118 with less resistance compared to conventional catheters.

[0039] At block 210, after delivery sheath 102 and endovascular device 120 is pushed out of delivery catheter 118 as shown in FIG. 4, delivery wire 112 is pushed forward relative to delivery braid 110 or delivery braid 110 is pulled relative to delivery wire 112. Endovascular device 120 is unsheathed from delivery sheath 102 and thereby disengaged from delivery system 100. Once endovascular device 120 is placed at target blood vessel 124, at block 212, delivery sheath 102 and delivery wire 112 may be pulled back into delivery catheter 118 and delivery catheter 118 removed from the patient. [0040] Advantageously, delivery system 100 protects the outer surface of endovascular device 100 from contact with the inner surface of delivery catheter 118, thereby substantially decreasing the friction of endovascular device 120 as it traverses delivery catheter 118 and delivered to its intended target. Delivery system 100 also protects endovascular device 120 from shear forces as it traverses delivery catheter 118, which is particularly advantageous for endovascular device 100 with delicate features such as thin-film covered stents or stents intended to deliver therapeutics (e.g., protein, small molecules, cell-based therapies, biological substrates, or other therapeutic). Shear forces during delivery of these devices may damage or de laminate the thin-film or the therapeutic from the surface of these devices. In conventional catheters, the inner surface of the catheter typically directly contacts endovascular devices, resulting in more friction and sheer forces.

[0041] Further, delivery system 100 advantageously allows for full resheathability of endovascular device 120 even after 100 % of endovascular device 120 is outside delivery catheter 118. Another advantage of delivery system 100 is that it uses delivery braid 110 as a braided shaft to push endovascular device 118 through delivery catheter 118, which has more torqueability and better force transmission than delivery systems based on wires alone.

[0042] In some embodiments, delivery sheath 102 has one or more longitudinal cuts 108 extending longitudinally from distal end 106 towards proximal end 104. Longitudinal cut 108 may extend from distal end 106 and terminate at any position along delivery sheath 102 (e.g., any intermediate position along delivery sheath 102 or all the way at proximal end 104 of delivery sheath 102). The length of longitudinal cut 108 may be approximately 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100 % of the longitudinal length of delivery sheath 102, where any value can form an upper or a lower end point of a range for the length of longitudinal cut 108, as appropriate. Delivery sheath 102 may have, for example, two longitudinal cuts 108 as shown in FIGS. 5 and 6, or four longitudinal cuts 108 as shown in FIG. 7. Delivery sheath 102 may open up radially at longitudinal cuts 108 to facilitate deployment of endovascular device 120. In other embodiments, delivery sheath 102 does not include any longitudinal cuts 108 as shown in FIG. 8.

[0043] In some embodiments, delivery sheath 102 includes a distal portion 126 and a flared proximal portion 128 that connects distal portion 126 to delivery braid 110 as shown in FIG. 3. Distal portion 126 extends longitudinally with a uniform or relatively uniform diameter from a proximal end to a distal end. A relatively uniform diameter may be, for example, a diameter varying up to ±10%, ±5%, ±1%, ±0.5%, or ±0.1%, as appropriate. Flared proximal portion 128 extends longitudinally with an increasing diameter from a proximal end connected to delivery braid 110 to a distal end connected to tubular portion 128. In other embodiments, the diameter of delivery sheath 102 is uniform or relatively uniform throughout. The diameter of delivery sheath 102 is equal or approximately equal to the diameter of delivery braid 110, and delivery sheath 102 is connected to delivery braid 110 without flared proximal portion 128 as shown in FIGS. 5, 6, and 7.

[0044] In some embodiments, proximal end 104 of delivery sheath 102 connectedly extends from delivery braid 110 as shown in FIGS. 1, 3, and 5. For example, delivery sheath 102 is integrated with delivery braid 110. In other embodiments, delivery sheath 102 is a separate piece from delivery braid 110 and is attached to delivery braid 110 using tubing 130 as shown in FIGS. 6 and 8. In an example, tubing 130 is a heat-shrink tubing that includes heat-shrink polymer material, and proximal end 104 of delivery sheath 102 is laminated on delivery braid 110 using such tubing 130. In other examples, proximal end 104 of delivery sheath 102 is attached to delivery braid 110 using an adhesive (e.g., glue or other adhesive), soldering, a wire, a string, and/or other means of fastening.

[0045] As shown in FIG. 9, in an alternative embodiment, delivery sheath 102 is formed from a hypotube (e.g., a nitinol (nickel titanium) hypotube, a stainless steel hypotube, or other hypotube). Delivery sheath 102 has laser-cut perforations 132 to improve flexibility of the hypotube. [0046] As shown in FIGS. lOA-lOC, in a further embodiment, delivery sheath 102 has a plurality of tips. Delivery sheath 102 may be formed from a flat sheet (e.g., a nitinol sheet, a stainless steel sheet, or other sheet) that is cut (e.g., using laser cutting) to form a flat pattern shown in FIG. 8A. Delivery sheath 102 in its flat form includes distal wire tips 134, a proximal ring portion 136, and struts 138 extending from proximal ring portion 136 to distal wire tips 134. Distal wire tips 134 may include or be attached to radiopaque markers. The length of distal wire tips 134 and width of struts may be increased or decreased as appropriate. Delivery sheath 102 unconstrained after shape setting to its three dimensional form is shown in FJG.-8¾

sheath 102 constrained inside a catheter 118 and surrounding endovascular device 120 is shown in FIG. 8C.

[0047] FIG. 11 is a diagrammatic side view of delivery sheath 102 extending from delivery braid 110. Delivery braid 110 includes an outer jacket 140, an inner liner 142, and braided tubing 144. In some examples, delivery sheath 102 extends from and is integrated with inner liner 142. In another example, delivery sheath 102 extends from and is integrated with outer jacket 140. In further examples, delivery sheath 102 includes two layers, one layer extending from and integrated with outer jacket 140, and another layer extending from and integrated with inner liner 142. Alternatively, delivery sheath 102 is a separate piece from outer jacket 140 and inner liner 142 as shown in FIGS. 6 and 8.

[0048] Outer jacket 140 is tubular and has a proximal end, a distal end, and a lumen extending therethrough. Outer jacket 140 may be composed of or include a thermoplastic elastomer (TPE) material such as a polyether block amide (PEBA) material (e.g., PEBAX© or other polyether block amide material). Outer jacket 140 may have a diameter 146 (e.g., an outer diameter, a mean diameter, or an inner diameter) between approximately 0.01 inches and approximately 0.1 inches. Diameter 146 may be the outer diameter of delivery braid 110.

Diameter 146 may be approximately 0.01 inches, 0.02 inches, 0.03 inches, 0.04 inches, 0.05 inches, 0.06 inches, 0.07 inches, 0.08 inches, 0.09 inches, or 0.1 inches, where any value can form an upper or a lower end point of a range for diameter 146, as appropriate.

[0049] Inner liner 142 is tubular and has a proximal end, a distal end, and a lumen extending therethrough. Inner liner 142 is disposed within outer jacket 140 and extends along the longitudinal direction of outer jacket 140. Inner liner 142 may be composed of or include a low-friction material such as PTFE or other low-friction material. Inner liner 142 has a thin wall with a thickness of, for example, less than approximately 0.005 inches, less than approximately 0.004 inches, less than approximately 0.003 inches, less than approximately 0.002 inches, or less than approximately 0.001 inches. The thickness of the thin wall may be, for example, approximately 0.0001 inches, 0.0005 inches, 0.001 inches, 0.002 inches, 0.003 inches, 0.004 inches, or 0.005 inches, where any value can form an upper or a lower end point of a range for the thickness of the thin wall, as appropriate. Inner liner 142 may have a diameter 148 (e.g., an outer diameter, a mean diameter, or an inner diameter of inner liner 142) between approximately 0.005 inches and approximately 0.1 inches. Diameter 148 may be the inner diameter of delivery braid 110. Diameter 148 may be approximately 0.005 inches, 0.01 inches, 0.02 inches, 0.03 inches, 0.04 inches, 0.05 inches, 0.06 inches, 0.07 inches, 0.08 inches, 0.09 inches, or 0.1 inches, where any value can form an upper or a lower end point of a range for the inner diameter, as appropriate.

[0050] Braided tubing 144 is tubular and has a proximal end, a distal end, and a lumen extending therethrough. Braided tubing 144 is disposed between outer jacket 140 and inner liner 142, and extends along the longitudinal direction of outer jacket 140 and inner liner 142.

Braided tubing 144 may be a tube formed from a braided mesh of wires. Braided tubing 144 has a diameter (e.g., an inner diameter, a mean diameter, or an outer diameter) that is intermediate of diameter 146 of outer jacket 140 and diameter 148 of inner lining 142.

[0051] Delivery sheath 102 includes distal portion 126 with a diameter 150 (e.g., an outer diameter, a mean diameter, or an inner diameter of distal portion 126) that is uniform or relatively uniform, and flared proximal portion 128 joining delivery braid 110 (e.g., outer jacket 140 and/or inner liner 142) to distal portion 126. Distal portion 126 may have diameter 150 between approximately 0.01 inches and approximately 0.1 inches. Diameter 150 may be approximately 0.01 inches, 0.02 inches, 0.03 inches, 0.04 inches, 0.05 inches, 0.06 inches, 0.07 inches, 0.08 inches, 0.09 inches, or 0.1 inches, where any value can form an upper or a lower end point of a range for diameter 150, as appropriate. A diameter of flared proximal portion 128 increases from a diameter of delivery braid 110 (e.g., diameter 148 and/or diameter 146) to diameter 150 of distal portion 126 as it extends delivery braid 110 to distal portion 126.

[0052] FIG. 12A is a laterally directed cross-sectional view of delivery sheath 102 with flared proximal portion 128 extending from delivery braid 110 as shown in FIGS. 3 and 11. FIG. 12B is a longitudinally directed cross-sectional view of delivery braid 110 in FIG. 12A. In an example, delivery braid 110 has an outer diameter (e.g., diameter 146 of outer jacket 140) of between approximately 0.024 inches and approximately 0.029 inches, and an inner diameter (e.g., diameter 148 of inner jacket 142) of approximately 0.016 inches and approximately 0.023 inches. Distal portion 126 of delivery sheath 102 has an outer diameter (e.g., diameter 150 of delivery sheath 102) of between approximately 0.026 inches and approximately 0.031 inches. Delivery sheath 102 has a thin wall with a thickness 152 of less than approximately 0.002 inches or less than approximately 0.001 inches. Delivery sheath 102 has a length 154 along its longitudinal axis corresponding to a length of endovascular device 120 such that delivery sheath 102 covers endovascular device 120 when endovascular device 120 is assembled in delivery device 100. Delivery sheath may have length 154 of between approximately 20 mm and approximately 30 mm. Delivery sheath 102 and delivery braid 110 together may have a length 156 of between approximately 25 cm and 250 cm (e.g., 175 cm).

[0053] FIG. 13A is a laterally directed cross-sectional view of delivery sheath 102 having a uniform or relatively uniform diameter extending from delivery braid 110 as shown in FIG. 11. FIG. 13B is a longitudinally directed cross-sectional view of delivery braid 110 in FIG. 13 A. In an example, delivery braid 110 and delivery sheath 102 have an outer diameter (e.g., diameter 146 of outer jacket 140 and diameter 150 of delivery sheath 102) of between approximately 0.026 inches and approximately 0.031 inches. Delivery braid has an inner diameter (e.g., diameter 148 of inner jacket 142) of approximately 0.018 inches and approximately 0.025 inches. Delivery sheath 102 has a thin wall with thickness 152 of less than approximately 0.002 inches or less than approximately 0.001 inches. Delivery sheath 102 has length 154 along its longitudinal axis corresponding to a length of endovascular device 120 such that delivery sheath 102 covers endovascular device 120 when endovascular device 120 is assembled in delivery device 100. Delivery sheath may have length 154 of between approximately 20 mm and approximately 30 mm. Delivery sheath 102 and delivery braid 110 together may have length 156 of between approximately 25 cm and 250 cm (e.g., 175 cm).

[0054] FIG. 14 is a diagrammatic side view of delivery wire 112. Delivery wire 112 includes a proximal section 158 and a coiled distal section 160. Proximal section 158 and/or distal section 160 may be composed of or include stainless steel, nitinol, and/or tungsten. Most of the length (e.g., more than half, more than 90%, more than 99%, etc.) of delivery wire 112 may be proximal section 158 and the rest (e.g., less than half, less than 10%, less than 1%, etc.) may be coiled distal section 160. Coiled distal section is coiled for flexibility and may be more flexible than proximal section 158.

[0055] FIG. 15 is a diagrammatic side view of delivery tip 114. Delivery tip 114 is tubular and includes a proximal section 162, an intermediate section 164 and a distal section 166. An outer diameter of proximal section 162 may be larger than an outer diameter of intermediate section 164 such that a step 168 is formed between proximal section 162 and intermediate section 164. Holes or grooves 116 are formed on intermediate section 164 to engage a proximal end of endovascular device 120. Distal section 166 may include slits for flexibility. Delivery tip 114 may be composed of or include stainless steel, nitinol, and/or tungsten. In an example, proximal section 162 may have an outer diameter of approximately 0.025 inches and an inner diameter of between 0.016 inches and 0.018 inches. Intermediate section 164 may have an outer diameter of approximately 0.020 inches and an inner diameter of between approximately 0.016 inches and approximately 0.018 inches. The outer diameter of delivery tip 114 changes from approximately 0.025 inches to approximately 0.020 inches at step 164.

[0056] FIG. 16 is a diagrammatic side view of delivery tip 114 of FIG. 15 assembled on delivery wire 112. Delivery tip 114 may be attached to coiled distal section 160 of delivery wire 122 with an adhesive 172 such as UV glue or solder.

[0057] In other embodiments, delivery tip 114 may include two parts 174 and 176, as shown in FIGS. 17A-B. FIG. 17A is a diagrammatic side view of part 174 of delivery tip 114, and FIG. 17B is a diagrammatic side view of part 176 of delivery tip 114. Parts 174 and 176 may be composed of or include stainless steel, nitinol, and/or tungsten. In an example, part 174 has an outer diameter of approximately 0.025 inches and an inner diameter of between approximately 0.016 inches and approximately 0.018 inches. Part 176 has an outer diameter of approximately 0.020 inches and an inner diameter of between approximately 0.016 inches and approximately 0.018 inches.

[0058] FIG. 18 is a diagrammatic side view of delivery tip 114 of FIGS. 17A-B assembled on delivery wire 112. Part 174 of delivery tip 114 may be attached to coiled distal section 160 of delivery wire 122 with an adhesive 178 such as UV glue or solder, and part 176 may also be attached to coiled distal section 160 of delivery wire 122 with an adhesive 180 such as UV glue or solder.

[0059] In further embodiments, delivery wire 112 includes delivery tip 114. Delivery tip 114 may be formed at the distal end of delivery wire 112 such that delivery tip 114 is not a separate piece but integrated with delivery tip 114.

[0060] FIG. 19A is an image of delivery tip 114 including part 174 and part 176 and coiled distal section 160 of delivery wire 112 before assembly of delivery tip 114 on delivery wire 112. FIG. 19B shows an image of delivery tip 114 including part 174 and part 176 assembled on coiled distal section 160 of delivery wire 112.

[0061] FIG. 20A is an image of delivery sheath 102 extending from delivery braid 110 and delivery tip 114 assembled on coiled distal section 160 of delivery wire 112. FIG. 20B is an image of delivery tip 114 inserted in delivery sheath 102 and coiled distal section 160 of delivery wire 112 inserted in delivery sheath 102 and delivery braid 110.

[0062] FIG. 21A is an image of endovascular device 120 and delivery tip 114 assembled on coiled distal section 160 of delivery wire 1 12. FIG. 21B is an image of endovascular device 120 with its proximal section crimped, assembled on delivery tip 1 14, and surrounded by delivery sheath 102.

[0063] FIG. 22A is an image of a proximal section of endovascular device 120 surrounded by delivery sheath 102 before being inserted into delivery catheter 118. FIG. 22B is an image of the proximal section of endovascular device 120 inserted into delivery catheter 118. FIG. 22C is an image of an intermediate section of endovascular device 120 before being inserted into delivery catheter 118. FIG. 22D is an image of endovascular device surrounded by delivery sheath 102 fully inserted into delivery catheter 118.

[0064] FIG. 23A is an image of endovascular device 120 with its proximal section crimped in delivery sheath 102 and its proximal end engaged with delivery tip 114. FIG. 23B is an image of endovascular device 120 with its intermediate section partially expanded as the intermediate section of endovascular device 120 is pushed out of delivery catheter 118. Delivery sheath 102 around the intermediate section is opened as a result of the intermediate section of endovascular device 120 self-expanding when pushed out of delivery catheter 118. FIG. 23C is an image of endovascular device 120 with its distal section fully expanded when the distal section is pushed out of delivery catheter 118. Delivery sheath 102 around the distal section is opened as a result of the distal section of endovascular device 120 self-expanding when pushed out of delivery catheter 118. [0065] Embodiments described herein illustrate but do not limit the disclosure. It should also be understood that numerous modifications and variations are possible in accordance with the principles of the present disclosure. Accordingly, the scope of the disclosure is best defined only by the following claims.

Claims

CLAIMS What is claimed is:

1. A delivery system, comprising:

a tubular delivery braid having a proximal end, a distal end, and a lumen extending therethrough, the tubular delivery braid configured to be selectively inserted into a catheter; a delivery wire having a proximal end and a distal end, the delivery wire being configured to be inserted into the lumen of the delivery braid and be selectively moveable along the delivery braid;

a delivery tip having a proximal end connected to the distal end of the delivery wire and a distal end configured to engage an endovascular device; and

a tubular delivery sheath having a proximal end connected to the distal end of the delivery braid and a distal end, the delivery sheath configured to surround the endovascular device and be selectively inserted into the catheter to contact the endovascular device with its inner surface and contact the catheter with its outer surface.

2. The delivery system of claim 1, wherein the delivery sheath comprises a low-friction material.

3. The delivery system of claim 2, wherein the low-friction material comprises

polytetrafluoroethylene PTFE).

4. The delivery system of claim 1, further comprising the catheter, wherein at least an inner surface of the catheter comprises a low-friction material.

5. The delivery system of claim 4, wherein the low-friction material comprises PTFE.

6. The delivery system of claim 1, wherein the delivery sheath is integrated with the delivery braid, the delivery sheath extending from the distal end of the delivery braid.

7. The delivery system of claim 1, wherein the delivery tip is integrated with the delivery wire, the delivery tip being formed at the distal end of the delivery tip.

8. The delivery system of claim 1, wherein the delivery sheath includes one or more longitudinal cuts extending from the distal end towards the proximal end.

9. The delivery system of claim 1, wherein the endovascular device is a covered stent or a therapeutic delivery stent.

10. The delivery system of claim 1, further comprising the endovascular device.

11. A method, comprising:

engaging an endovascular device to a delivery tip connected to a delivery wire;

inserting the delivery wire into a delivery braid;

covering the endovascular device with a delivery sheath connected to the delivery braid; inserting the endovascular device covered with the delivery sheath into a catheter;

pushing the endovascular device covered with the delivery sheath out of the catheter; and removing the delivery sheath from the endovascular device.

12. The method of claim 11, wherein the covering of the endovascular device with the delivery sheath comprises contacting an inner surface of the delivery sheath with the endovascular device.

13. The method of claim 11, wherein the inserting of the endovascular device covered with the delivery sheath into the catheter comprises contacting an outer surface of the delivery sheath with an inner surface of the catheter.

14. The method of claim 11, wherein the inserting of the endovascular device covered with the delivery sheath into the catheter comprises inserting the delivery braid into the catheter and pulling the delivery braid along the catheter.

15. The method of claim 11, wherein the pushing of the endovascular device covered with the delivery sheath out of the catheter comprises pushing the delivery braid along the catheter.

16. The method of claim 11, wherein the removing of the delivery sheath from the endovascular device comprises pushing the delivery wire along the delivery braid or pulling the delivery braid relative to the delivery wire.

17. The method of claim 11, further comprising positioning a distal end of the catheter at a target aneurysm site of a patient.

18. The method of claim 11, further comprising forming the delivery sheath from low- friction material such that friction between the delivery sheath and the catheter is reduced during the pushing of the endovascular device covered with the delivery sheath out of the catheter.