Method for laminating ePTFE to nitinol braided fabric with smooth outer diameter
By laminating the ePTFE bushing on the expandable Nitinol tube structure, the problem of a larger opening in the artery in the prior art is solved, and a tighter sheath structure is achieved, which improves operating safety and comfort.
Patent Information
- Application Number
- CN202380055177.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-07-22
- Filing Date
- 2023-07-21
- Publication Date
- 2025-04-11
AI Technical Summary
The existing expandable guide sheath requires a larger incision opening during arteriotomy, affecting operational safety and comfort.
By laminating the expanded polytetrafluoroethylene (ePTFE) bushing on the expandable nitinol tube structure, the ePTFE bushing is brought into contact with the heating mold by inflatable silicone tube, and the lamination effect is achieved, thereby forming a tighter sheath structure.
Reduces the size of the incision opening required for arteriotomy, improves the safety and comfort of the operation, while enhancing the sealing and durability of the sheath.
Smart Images
Figure CN119816408A_ABST
Abstract
Description
[0001] CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 391,384, filed on July 22, 2022, and is incorporated herein by reference. Technical Field
[0003] A method of attaching ePTFE to a nitinol structure, such as an expandable sheath, is described. Background Art
[0004] An intracardiac heart pump assembly can be introduced into the heart surgically or percutaneously and used to transport blood from one location of the heart or circulatory system to another location of the heart or circulatory system. For example, when deployed in the heart, the intracardiac pump can pump blood from the left ventricle of the heart into the aorta, or pump blood from the inferior vena cava into the pulmonary artery. The intracardiac pump can be powered by a motor (and accompanying drive cable) located outside the patient's body or by an onboard motor located inside the patient's body. Some intracardiac blood pump systems can run in parallel with the natural heart to supplement cardiac output and partially or completely unload components of the heart. Examples of such systems include Series of equipment (Abiomed, Inc., Danvers Mass.).
[0005] In one common approach, an intracardiac blood pump is inserted through the femoral artery via a catheterization procedure using an introducer sheath (which may be a peel-away introducer sheath. The sheath may alternatively be inserted into other locations, such as the femoral vein or any route for delivering the pump to support the left or right side of the heart.
[0006] An introducer sheath can be inserted through an arteriotomy into the femoral artery to create an insertion path for the pump assembly. A portion of the pump assembly is then advanced through the lumen of the introducer sheath and into the artery. The necessary size of the arteriotomy is a matter of concern. Therefore, expandable introducer sheaths have been developed, requiring a smaller arteriotomy opening to accommodate the sheath and the medical device passing therethrough. Therefore, improvements in expandable introducer sheaths continue to be sought. Summary of the invention
[0007] A method for laminating an expanded polytetrafluoroethylene (ePTFE) liner onto the surface of an expandable tube, which may be made of nitinol or braided nitinol, is described herein. Both ePTFE and nitinol are well known materials and are not described in detail herein. The method deploys an inflatable silicone tube that, when inflated, brings one of the inner ePTFE liner and / or the outer ePTFE liner into contact with a heated mold that laminates the ePTFE liner onto the expandable tube.
[0008] In one aspect, a method of making an expandable sheath is described. According to one aspect of the method, an expandable tubular structure is placed within an outer liner. An inner liner is inserted into the expandable tubular structure. The expandable tubular structure having the inner liner and the outer liner is placed on an inflatable silicone tube. The inflatable silicone tube is placed in a heated mold, which is located between the inflatable silicone tube and the inner liner or outside the outer liner. The silicone tube is inflated so that the inner liner and the outer liner are laminated to the expandable tubular structure by contacting one of the inner liner or the outer liner with the heated tube. The heated mold is then cooled and the silicone tube is depressurized to deflate it. The laminated expandable sheath is removed from the mold and the inflatable silicone tube.
[0009] In one aspect, each of the inner and outer bushings is expanded polytetrafluoroethylene (ePTFE). In another aspect, thermoplastic polyurethane is applied to the inner surface of the outer bushing or the outer surface of the inner bushing.
[0010] In one aspect, the expandable tubular structure is made of braided nitinol wire.
[0011] In a further aspect, pressurizing the inflatable silicone tube forces the inner sleeve and the outer sleeve to contact the inner surface of the braided structure and the inner surface of the heated mold, respectively. In one aspect of the above, the free outer diameter of the inflatable silicone tube is less than the inner diameter of the inner sleeve. In a further aspect, the inflatable silicone tube is configured to expand to an outer diameter that causes one of the inner sleeve or the outer sleeve to contact the heated mold. In one aspect, the inflatable silicone tube is located inside the inner sleeve.
[0012] In one aspect, the heated mold is located outside the outer liner. In an optional aspect, the heated mold is located inside the inner liner. In one aspect, the heated mold is heated to a temperature of 110°C. In one aspect, the inflatable silicone tube has a softer hardness of about 10 Shore A to about 50 Shore A. In one aspect, the inner liner of the laminated expandable sheath has an irregular surface consistent with the contour of the braided structure. In another aspect, the outer liner of the laminated expandable sheath has a smooth surface. In a further aspect, the laminated expandable sheath includes an inner liner, an outer liner, and an expandable tubular frame structure located between the inner liner and the outer liner.
[0013] Also described is an expandable laminated sheath having: an expandable tubular frame structure having an inner surface and an outer surface, and an expanded polytetrafluoroethylene inner liner laminated to the inner surface of the nitinol expandable braided tube structure and an expanded polytetrafluoroethylene outer liner laminated to the outer surface of the nitinol expandable braided tube structure, wherein the expandable laminated sheath is formed by inserting an inflatable silicone tube into the inner liner and inflating the silicone tube until the inner surface of the inner liner or the outer surface of the outer liner contacts a heated mold.
[0014] In one aspect, one of the outer surface of the inner sleeve or the inner surface of the outer sleeve is coated with thermoplastic polyurethane. In one aspect, the expandable tubular frame is a nitinol braided structure. In one aspect, the inner sleeve and the outer sleeve are formed of expanded polytetrafluoroethylene (ePTFE). BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The described aspects are illustrated in the accompanying drawings.
[0016] Figure 1 Illustrated is a cross section of a Nitinol structure with inner and outer ePTFE liners.
[0017] Figure 2 Illustrated is a cross section of a heated mold according to one aspect of the present technology.
[0018] Figure 3 Illustrated is a cross section of a silicone tube in accordance with one aspect of the present technology.
[0019] Figure 4 Illustrated Figure 1-3 Components of the structure illustrated in , which can be used to manufacture ePTFE laminated nitinol structures.
[0020] Figure 5 Illustrated is how, in one aspect of this technology, silicone tubing is used to laminate an ePTFE sleeve to a nitinol braid.
[0021] Figure 6 Illustrated is how, according to one aspect of the technology, an inner ePTFE liner is laminated to the inner diameter of a nitinol braid while the outer ePTFE liner remains smooth.
[0022] Figure 7 Illustrated is how, according to one aspect of the technology, an outer ePTFE liner is laminated to the outer diameter of a nitinol braid while the inner ePTFE liner remains smooth.
[0023] Figure 8 is a flow chart according to one aspect of the method described herein. DETAILED DESCRIPTION
[0024] Embodiments of the present disclosure are described in detail with reference to the accompanying drawings, wherein like reference numerals represent similar or identical elements. It should be understood that the disclosed embodiments are merely examples of the present disclosure, which may be embodied in various forms. In order to avoid obscuring the present disclosure with unnecessary details, well-known functions or configurations are not described in detail. Therefore, the specific structural and functional details disclosed herein should not be interpreted as limiting, but only as a basis for the claims and as a representative basis for teaching those skilled in the art to use the present disclosure in various ways in almost any appropriately detailed structure.
[0025] In one aspect, an ePTFE sleeve is attached to the inner surface of the tubular frame. In another aspect, a primer is formed between the ePTFE sleeve and the inner surface of the lumen defined by the tubular frame. In another aspect, the introducer sheath assembly has an outer ePTFE sleeve formed on the outer surface of the tubular frame. In another aspect, the introducer sheath assembly has an inner ePTFE sleeve and an outer ePTFE sleeve formed on both the inner and outer surfaces of the tubular frame. The tubular frame can be made of braided nitinol wire. Nitinol is a well-known alloy of nickel and titanium, wherein the percentages of nickel and titanium are approximately equal.
[0026] Reference Figure 1 , illustrates an expandable sheath structure 100 having a nitinol structure 110 with an inner sleeve 120 of ePTFE and an outer sleeve 130 of ePTFE. Each of the nitinol structure 110, the inner ePTFE sleeve 120, and the outer ePTFE sleeve 130 is a tube.
[0027] In one aspect, the Nitinol structure is a braided Nitinol wire structure having the following features, which are provided by way of example and not limitation.
[0028] i. The outer diameter (OD) of the nitinol structure is about 3.9 to about 4.1 mm; the nitinol structure is formed of a braid of hard nitinol wire having a diameter of about 75 μm to about 125 μm. The nitinol can be SE508 nitinol. In one aspect, an activation temperature (Af) of about 10°C to about 20°C is used; the braid is braided or twisted together in a 48-end, 2×2 braid pattern on a pin of about 4.15 mm at a pressure of about 16.5 PPI to about 17.6 PPI (pounds per square inch), including a braid angle of about 34° to about 40°; and
[0029] ii. Thermoplastic polyurethane (TPU) primer (applied in an amount of about 20 mg to about 60 mg for a 150 cm long Nitinol braid). In one example, the hardness is about 75 Shore A, the specific gravity is about 1.1 to about 1.4 SG, and the tensile strength at 50% elongation is about 100 psi to about 650 psi. The ultimate elongation of the material is about 350% to about 750%. The properties of Nitinol and polyurethane are well known, and these are examples of the properties of these materials suitable for the claimed structures. As used herein, it is about ±10% of the indicated value.
[0030] Each of the inner and outer ePTFE bushings has the following features, which are provided by way of example only and not limitation.
[0031] i. Each ePTFE bushing has an inner diameter (ID) of about 3.9 mm to about 4.1 mm; each ePTFE bushing has a thickness of about 0.040 mm to about 0.060 mm, a density of about 0.4 g / cc, and a tensile strength at 50% elongation of about 0.15 to about 0.45 N / mm; and
[0032] ii. TPU OD seal (for a 150 cm long ePTFE liner, the amount applied may be about 30 mg to about 75 mg). In one example, the hardness may be about 42-73 Shore A, the specific gravity may be about 0.96 SG to about 1.04 SG, and the tensile strength at 50% elongation may be about 130 psi to about 455 psi. The ultimate elongation of the material may be about 500% to about 626%.
[0033] The properties of ePTFE are well known, and these are examples of properties of materials suitable for the claimed structures.
[0034] Reference Figure 2 , which illustrates a heated mold 200 defining an inner diameter approximately equal to a target final outer diameter of an expandable sheath having an inner ePTFE sleeve 120 and an outer ePTFE sleeve 130 laminated to a nitinol structure. In one aspect, the target final outer diameter is about 4.5 mm to about 4.6 mm.
[0035] Reference Figure 3, which illustrates a silicone tube 300A having a free outer diameter that is less than the inner diameter of the inner ePTFE liner 120, but configured to expand to an outer diameter 300B that is greater than the diameter of the inner ePTFE liner 120 under internal pressure. As used herein, the free outer diameter is the outer diameter of the silicone tube when it is in an uninflated state. Preferably, the outer diameter (OD) of the inflatable silicone tube is about 3.0 mm to about 3.8 mm, and the inner diameter (ID) is about 1.0 mm to about 3.3 mm. In one example, the hardness is about 10 Shore A to about 50 Shore A, and the internal pressure of the inflatable silicone tube is about 1.6 psi to about 7 psi. In one aspect, the heated mold 200 is configured to reach about 90°C to about 150°C in about 2-20 minutes. The heated mold 200 is cooled by "heat off" for about 5 to about 20 minutes, wherein the air flow lasts for about 1 to about 10 minutes, and wherein the water cooling lasts for about 1 to about 5 minutes.
[0036] Reference Figure 4 , illustrates an assembly of an inner ePTFE inner sleeve 120 and an outer ePTFE sleeve 130 with a nitinol braid 110 located therebetween. An inflatable silicone tube 300A is located within the inner ePTFE sleeve 120, and a heated mold 200 is located outside the outer ePTFE outer sleeve 130. According to the method, the heated mold 200 is heated to a temperature of 110°C, and a nitinol structure (with inner and outer ePTFE sleeves) is loaded onto the inflatable silicone tube and then slid into the heated mold 200.
[0037] Reference Figure 5 , illustrated Figure 4 , wherein the silicone tube 300B has been inflated. The structure (the Nitinol structure 110 between the inner ePTFE sleeve 120 and the outer ePTFE sleeve 130) is pressed against the inner surface of the heated mold 200. Because silicone has a softer durometer (e.g., Shore 10A to about 50A), the silicone tube 300B will press upward into the Nitinol braid 110, laminating the inner ePTFE sleeve 120 to the inner diameter of the Nitinol braid structure 110.
[0038] Reference Figure 6, illustrates a partial cross-section of an assembly after removal from a tool (the tool is a heated mold and an inflatable silicone tube). The assembly is removed by deflating (reducing pressure) the inflatable silicone tube. The inner ePTFE sleeve 120 has an irregular surface that conforms to the contour of the braided nitinol structure 110. The outer ePTFE sleeve 130 has a smooth surface. When in use, the inner surface of the assembly is flushed with saline. Therefore, due to flow dynamics, the inner surface may not pose a long-term risk of thrombosis. The inner surface also reduces the surface area in contact with devices passing through the structure, which reduces the insertion force required for these devices.
[0039] Figure 7 yes Figure 6 An alternative aspect is illustrated in . Figure 7 The structure in is fabricated by providing a heated mold (not shown) within the inner diameter of an inner ePTFE liner 120. An inflatable silicone tube is placed on the outer diameter of the structure and applies pressure to the outer ePTFE liner 130 when inflated. The resulting structure has a smooth inner ePTFE liner 120 and a conformal outer ePTFE liner 130. The textured outer ePTFE coated diameter introduces a risk of thrombosis through low surface shear rates, low velocities, and areas of blood recirculation.
[0040] Figure 8 A method of making the expandable sheath structure described herein is described. Initially, in step 501, a nitinol braided structure is slid into or placed into an outer ePTFE sleeve. In step 502, an inner ePTFE sleeve is slid into or placed into the nitinol braided structure. In step 503, the assembly of the nitinol braided structure and the inner and outer ePTFE sleeves is slid into or inserted onto an inflatable silicone tube such that the inflatable silicone tube is within the lumen of the assembly. In step 504, the assembly inserted onto the silicone tube is placed into a heated mold such that the heated mold surrounds the assembly. In step 505, the inflatable silicone tube is pressurized to inflate it, forcing the inner ePTFE sleeve to contact the inner surface of the nitinol braided structure, and squeezing the nitinol braided structure to force the outer ePTFE sleeve to contact and press against the inner surface of the heated mold 200. Thus, pressurizing the inflatable silicone tube allows the inner ePTFE sleeve and the outer ePTFE sleeve to be laminated to the inner surface of the braided structure and the outer surface of the braided structure, respectively, to form an expandable sheath structure. In step 506, the heated mold is cooled. In step 507, the silicone tube is depressurized to deflate the inflatable silicone tube. In step 508, the laminated expandable sheath structure is removed from the mold and the inflatable silicone tube.
[0041] The present invention describes a method for manufacturing an expandable sheath, which includes: i) sliding an expandable tubular structure into an outer sleeve; ii) sliding an inner sleeve into the expandable tubular structure; iii) inserting the assembly of the expandable tubular structure, the inner sleeve and the outer sleeve onto an inflatable silicone tube; iv) placing the assembly with the inflatable silicone tube in a heated mold; v) pressurizing the inflatable silicone tube to inflate the inflatable silicone tube so as to laminate the inner sleeve and the outer sleeve to the inner surface of the expandable tubular structure and the outer surface of the expandable tubular structure, respectively, to form an expandable sheath; vi) cooling the heated mold; vii) depressurizing the silicone tube so as to deflate the inflatable silicone tube; and viii) removing the laminated expandable sheath from the mold and the inflatable silicone tube.
[0042] In the above method, each inner sleeve and outer sleeve is expanded polytetrafluoroethylene (ePTFE). In any of the above aspects, thermoplastic polyurethane is applied to the inner surface of the outer sleeve. In any of the above aspects, thermoplastic polyurethane is applied to the outer surface of the inner sleeve. In any of the above aspects, the expandable tubular structure is made of braided nitinol wire. In any of the above aspects, pressurizing the inflatable silicone tube can force the inner sleeve and the outer sleeve to contact the inner surface of the expandable tubular structure and the inner surface of the heated mold, respectively. In any of the above aspects, the free outer diameter of the inflatable silicone tube is smaller than the inner diameter of the inner sleeve. In any of the above aspects, the inflatable silicone tube is configured to expand to an outer diameter that causes one of the inner sleeve or the outer sleeve to contact the heated mold. In any of the above aspects, the inflatable silicone tube is located inside the inner sleeve. In any of the above aspects, the heated mold is located outside the outer sleeve. In any of the above aspects, the heated mold is located inside the inner sleeve. In the above aspects, the heated mold is heated to a temperature of 110°C. In any of the above aspects, the inflatable silicone tube may have a softer durometer of about 10 Shore A to about 50 Shore A. In any of the above aspects, the inner liner of the laminated expandable sheath has an irregular surface that conforms to the contour of the expandable tubular structure. In any of the above aspects, the outer liner of the laminated expandable sheath may have a smooth surface. In any of the above aspects, the laminated expandable sheath may include an inner liner, an outer liner, and an expandable tubular structure located between the inner liner and the outer liner.
[0043] Also described herein is an expandable laminated sheath having: an expandable tubular frame structure having an inner surface and an outer surface; an expanded polytetrafluoroethylene inner sleeve laminated to the inner surface of the nitinol expandable tubular frame structure; and an expanded polytetrafluoroethylene outer sleeve laminated to the outer surface of the expandable tubular structure. In any of the above aspects, the expandable can be formed by inserting an inflatable silicone tube into the inner sleeve and inflating the silicone tube until the inner surface of the inner sleeve or the outer surface of the outer sleeve contacts the heated mold. According to the above aspects, one of the outer surface of the inner sleeve or the inner surface of the outer sleeve is coated with thermoplastic polyurethane. According to the above aspects, the expandable tubular frame is a nitinol structure formed by braiding nitinol wire. In any of the above aspects, the inner sleeve and the outer sleeve can be made of expanded polytetrafluoroethylene (ePTFE).
[0044] Based on the above and with reference to the various drawings, it will be understood by those skilled in the art that certain modifications may be made to the present disclosure without departing from the scope of the present disclosure. Although several embodiments of the present disclosure are illustrated in the drawings, it is not intended to limit the present disclosure thereto, because the present disclosure is intended to be as extensive as possible within the scope permitted by the art, and the specification is also intended to be as extensive as possible within the scope permitted by the art. Therefore, the above description should not be interpreted as limiting, but only as an example of a specific embodiment. Those skilled in the art will envision other modifications within the scope and spirit of the appended claims.
Claims
1. A method for manufacturing an expandable sheath, the method comprising: sliding the expandable tubular structure into the outer sleeve; sliding an inner liner into the expandable tubular structure; inserting the assembly of the expandable tubular structure, the inner sleeve and the outer sleeve onto an inflatable silicone tube; placing the assembly with the inflatable silicone tube into a heated mold; pressurizing the inflatable silicone tube to inflate the inflatable silicone tube to laminate the inner liner and the outer liner to the inner surface of the expandable tubular structure and the outer surface of the expandable tubular structure, respectively, to form the expandable sheath; cooling the heated mold; decompressing the silicone tube, thereby deflating the inflatable silicone tube; and The laminated expandable sheath is removed from the mold and the inflatable silicone tube.
2. The method of claim 1, wherein each of the inner and outer sleeves is expanded polytetrafluoroethylene (ePTFE).
3. A method according to any one of claims 1 and 2, wherein thermoplastic polyurethane is applied to the inner surface of the outer bushing.
4. The method according to any one of claims 1 and 2, wherein thermoplastic polyurethane is applied to the outer surface of the inner bushing.
5. The method of any one of claims 1 to 4, wherein the expandable tubular structure is made of braided Nitinol wire.
6. The method of any one of claims 1 to 5, wherein pressurizing the inflatable silicone tube forces the inner and outer sleeves into contact with the inner surface of the expandable tubular structure and the inner surface of the heated mold, respectively.
7. The method of any one of claims 1 to 6, wherein the inflatable silicone tube has a free outer diameter that is smaller than the inner diameter of the inner liner.
8. The method of any one of claims 1 to 7, wherein the inflatable silicone tube is configured to expand to an outer diameter that causes one of the inner sleeve or the outer sleeve to contact the heated mold.
9. The method of any one of claims 1 to 8, wherein the inflatable silicone tube is located inside the inner liner.
10. The method of any one of claims 1 to 8, wherein the heated mould is located external to the outer sleeve.
11. The method of any one of claims 1 to 8, wherein the heated mold is located inside the inner liner.
12. A method according to any one of claims 1 to 11, wherein the heated mould is brought to a temperature of 110°C.
13. The method of any one of claims 1 to 12, wherein the inflatable silicone tube has a softer durometer of about 10 Shore A to about 50 Shore A.
14. The method of any one of claims 1 to 13, wherein the inner lining of the laminated expandable sheath has an irregular surface that conforms to the contour of the expandable tubular structure.
15. The method of any one of claims 1 to 14, wherein the outer lining of the laminated expandable sheath has a smooth surface.
16. The method of any one of claims 1 to 15, wherein the laminated expandable sheath comprises the inner liner, the outer liner, and the expandable tubular structure between the inner and outer liner.
17. An expandable laminate sheath comprising: an expandable tubular frame structure having an inner surface and an outer surface; an expanded polytetrafluoroethylene inner liner laminated to the inner surface of the nitinol expandable tubular framework structure; an expanded polytetrafluoroethylene outer liner laminated to an outer surface of the expandable tubular structure; and The expandable laminated sheath is formed by inserting an inflatable silicone tube into the inner sleeve and inflating the silicone tube until the inner surface of the inner sleeve or the outer surface of the outer sleeve contacts a heated mold.
18. The expandable laminate sheath of claim 17, wherein one of the outer surface of the inner liner or the inner surface of the outer liner is coated with thermoplastic polyurethane.
19. The expandable laminate sheath according to any one of claims 17 and 18, wherein the expandable tubular frame is a Nitinol structure formed of braided Nitinol wires.
20. The expandable laminate sheath of any one of claims 17 to 19, wherein the inner and outer sleeves are formed from expanded polytetrafluoroethylene (ePTFE).