Expander sheath assembly with interlocking arrangement

Abstract

A sheath assembly (100) is provided, comprising an expandable guide sheath (130) and an expander assembly (200). The sheath assembly (100) includes an expandable sheath (130) having a stepped feature (360) within its distal opening; the expander assembly (200) includes an expander having an expander body (210); and an interlocking device (240) including a gripping surface (244) configured to engage with the stepped feature of the expandable sheath. When the stepped feature engages the gripping surface, it prevents further relative movement, thereby preventing the body of the expander from disengaging from the distal end of the expandable sheath. The nature of the interlocking engagement between the stepped feature and the gripping surface allows the expander to extend and maintain tension on the expandable sheath during insertion into the patient, and then retract from the expandable sheath by simply pulling the expander in the opposite direction. The expander assembly (200) also includes an expander hub (230) having a spring mechanism (270) configured to achieve and maintain a desired tension on the expandable sheath and to prevent overstretching of the expandable sheath when the expander (210) is inserted into the expandable sheath.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 969,318, filed February 3, 2020, the disclosure of which is incorporated herein by reference in its entirety. This application relates to U.S. Patent Publication No. 2019 / 0247627A1, filed February 15, 2019, entitled “Expandable Introducer Sheath for Medical Device”, under U.S. Application Serial No. 16 / 277,378 (which is incorporated herein by reference). This application also relates to U.S. Patent Publication No. 2018 / 0256859A1, filed March 9, 2018, under U.S. Application Serial No. 15 / 917,042, entitled “Expandable Introducer Sheath for Medical Device” (which is incorporated herein by reference). Background Technology

[0003] An intracardiac pump assembly can be surgically or percutaneously introduced into the heart and is used to deliver blood from one location in the heart or circulatory system to another. For example, when deployed in the heart, an intracardiac pump can pump blood from the left ventricle into the aorta, or from the inferior vena cava into the pulmonary artery. The intracardiac pump can be powered by a motor (and associated drive cable) located outside the patient or by an onboard motor located inside the patient. Some intracardiac pump systems can operate in parallel with the natural heart to supplement cardiac output and partially or completely offload components of the heart. Examples of such systems include... A series of devices (Abiomed, Inc., Danvers Mass.).

[0004] In a common approach, the intracardiac pump is inserted via a catheterization procedure using a sheath (such as a stripper sheath) inserted through the femoral artery. The sheath can alternatively be inserted in other locations, such as the femoral vein or in any delivery pathway that supports the left or right side of the heart.

[0005] A guide sheath can be inserted into the femoral artery via arteriotomy to create an insertion path for the pump assembly. A portion of the pump assembly is then advanced through the guide's internal lumen and into the artery. After the pump assembly has been inserted, the guide sheath is dissected. A repositioning sheath can then be advanced over the pump assembly and into the arteriotomy. Replacing the guide sheath with a repositioning sheath during medical device insertion reduces limb ischemia and bleeding at the insertion site in the skin (and / or the insertion site within the blood vessel) because the sheath is better secured to the patient when used with a hemostatic valve.

[0006] Because commercially available tear-off guide sheaths are not radially expandable, the inner diameter of the guide sheath must always be large enough to accommodate the largest diameter portion of the pump assembly (such as the pump head), even if other parts of the pump assembly (such as the catheter) have significantly smaller diameters. In this example, the guide creates an opening with a wider outer diameter than necessary to allow the pump catheter to pass through and enter the blood vessel. The guide sheath is then peeled or torn off and replaced with a lower-profile repositioning sheath. Removing the guide sheath by peeling it off presents several challenges. For example, the guide may tear off too easily and / or prematurely, leading to bleeding or vascular complications. Some guides may require excessive force to tear off for removal. If the physician applies too much force, they may inadvertently move the pump's position within the heart when the guide is finally torn off. This configuration also complicates the design of the hemostatic valve located in the hub of the guide, which also needs to be torn off. Furthermore, peeling off the guide sheath results in a larger vascular opening after the system is removed, complicating vascular closure.

[0007] Medical guides for applications other than cardiac pump insertion have an expandable sheath body that can expand radially to allow percutaneous devices to pass through and enter the patient's vascular system. These existing expandable guides are intended for relatively short-term use and can be designed to prevent thrombosis between the sheath body and the indwelling catheter.

[0008] These guides, with an inner diameter smaller than the outer diameter of the device being introduced, are inserted. The guide expands to allow the device to pass through the sheath and into the vascular system, and can then shrink again after the device has passed through. In the current state of the industry, these expandable guides require unique expandable features, such as longitudinal folds or creases, or lumens for fluid (e.g., saline) injection, to transition from a compressed to an expanded state. Because these existing expandable guides are intended for relatively short-term use, clot formation outside the guide sheath is unlikely. However, if longer time periods are allowed (e.g., >1 hour, >2 hours, >6 hours, >1 day, >2 days, >1 week), clots may form on the outer surface of the expandable sheath mesh and risk being displaced into the bloodstream after a period of time. Additionally, some commercially available expandable sheaths are completely flexible and therefore do not provide any stiffness within their structure, leading to kinking or buckling during the insertion or removal of percutaneous medical devices. Summary of the Invention

[0009] This technology relates to an expandable guide sheath with an interlocking dilator. More specifically, this technology provides an expandable sheath having a stepped feature within its distal opening, and a dilator with an interlocking device comprising a catch surface configured to engage with the stepped feature of the expandable sheath. When the stepped feature engages the catch surface, it prevents further relative movement, thereby preventing the body of the dilator from disengaging from the distal end of the expandable sheath. The nature of the interlocking engagement between the stepped feature and the catch surface allows the dilator to extend and maintain tension on the expandable sheath during insertion into a patient, and then retract from the expandable sheath by simply pulling the dilator in the opposite direction. This technology also provides a dilator hub with a spring mechanism configured to achieve and maintain desired tension on the expandable sheath and prevent over-extension of the expandable sheath when the dilator is inserted into the expandable sheath.

[0010] One aspect of the invention relates to a device comprising an expandable sheath and an expander. The expandable sheath comprises a cylindrical or substantially cylindrical expandable frame having a proximal opening, a distal opening, an inner surface, and an outer surface. The expandable sheath further comprises a material covering a portion of the outer surface and the inner surface of the expandable frame, and forming a stepped feature within the distal opening, the stepped feature having a first surface adjacent to and oriented at a first angle relative to the inner surface of the expandable frame. The expander comprises a cylindrical or substantially cylindrical body, a tapered tip, and an interlocking device between the body and the tapered tip. The interlocking device has: a first cylindrical segment having a first outer diameter; a second cylindrical segment having a second outer diameter smaller than the first diameter; and a gripping surface adjacent to and oriented at a second angle relative to the first cylindrical segment. The expander is configured to be inserted into the expandable sheath through the proximal opening of the expandable frame. The gripping surface is configured to engage the first surface to prevent the body of the expander from protruding from the expandable frame through the distal opening.

[0011] In some aspects, the device may further include: a sheath hub configured to secure the expandable sheath near a proximal opening of the expandable frame; and an expander hub. The expander hub includes: a dilator insert mold configured to secure the body of the expander; a spring configured to engage the dilator insert mold and prevent movement of the dilator insert mold within the expander hub; and one or more latches configured to lock the expander hub to the sheath hub.

[0012] In some aspects, the interlocking device further includes a tapered section adjacent to the second cylindrical section. In some aspects, the tapered section is further configured to engage a portion of the material near the distal opening of the expandable frame.

[0013] In some respects, the first angle is 90 degrees. In other respects, the first angle is less than 90 degrees.

[0014] In some respects, the second angle is 90 degrees. In other respects, the second angle is less than 90 degrees.

[0015] In some respects, the radial height of the stepped feature is between 0.1 mm and 5 mm.

[0016] In some respects, the material is a polymer, such as thermoplastic polyurethane.

[0017] In some aspects, the expandable frame is a braided material and may include strands of nitinol.

[0018] In some aspects, the expandable sheath further includes a coating, such as a smooth coating, applied to the expandable frame and the material.

[0019] In some aspects, the interlocking device is made of stainless steel and may be further coated with a polymer. In other aspects, the interlocking device is formed of a polymer.

[0020] In some respects, the tapered tip is formed from a polymer such as a polyether block amide. Attached Figure Description

[0021] Figure 1 An example of a sheath assembly is provided;

[0022] Figure 2 An example of an expander assembly is provided;

[0023] Figure 3A and Figure 3B Example Figure 2 Interlocking device for the expansion assembly;

[0024] Figure 4 yes Figure 2 Isometric sectional view of the expander hub of the expander assembly;

[0025] Figure 5 yes Figure 4 A cross-sectional side view of the expander hub of the expander assembly;

[0026] Figure 6 It is attached to Figure 1 Sheath assembly Figure 4 A cross-sectional side view of the expander hub of the expander assembly;

[0027] Figure 7 Is locked to Figure 1 On the sheath assembly Figure 4 A cross-sectional side view of the expander hub of the expander assembly;

[0028] Figure 8 Based on all aspects of this disclosure Figure 1 A cross-sectional side view of the distal end of the sheath assembly.

[0029] Figure 9 Based on all aspects of this disclosure Figure 1 A cross-sectional side view of the distal end of the sheath assembly.

[0030] Figure 10A This is a cross-sectional side view of a portion of the expander according to various aspects of this disclosure.

[0031] Figure 10B yes Figure 10A Zhongyu Figure 8 A near-cross-sectional view of the component where the sheath tip engages.

[0032] Figure 11 yes Figure 10A Zhongyu Figure 9 A near-cross-sectional view of the component where the sheath tip engages. Detailed Implementation

[0033] Embodiments of this disclosure have been described in detail with reference to the accompanying drawings, wherein like reference numerals identify similar or identical elements. It should be understood that the disclosed embodiments are merely examples of this disclosure and can be embodied in various forms. To avoid obscuring this disclosure with unnecessary detail, well-known functions or constructions have not been described in detail. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but rather as the basis for the claims and as a representative basis for teaching those skilled in the art to use this disclosure in various ways with virtually any suitable detailed structure.

[0034] To provide a full understanding of the systems, methods, and apparatuses described herein, certain exemplary embodiments will be described. While embodiments and features described herein are specifically described for use in conjunction with intracardiac cardiac pump systems, it will be understood that all components and other features outlined below can be combined with each other in any suitable manner and are applicable to and can be used with other types of medical devices, such as electrophysiological research and catheter ablation devices, angioplasty and stent implantation devices, angiography catheters, peripherally inserted central catheters, central venous catheters, midline catheters, peripheral catheters, inferior vena cava filters, abdominal aortic aneurysm therapy devices, thrombectomy devices, TAVR delivery systems, cardiac therapy and cardiac assist devices, including balloon pumps, cardiac assist devices implanted via surgical incisions, and any other guided catheters and devices based on veins or arteries.

[0035] The systems, methods, and apparatus described herein provide an expandable sheath assembly for inserting a medical device (e.g., an intracardiac cardiac pump) into a blood vessel through a vascular orifice. The expandable sheath assembly includes a dilator assembly and a sheath body having an inner surface and an outer surface, the inner surface defining a lumen extending between the proximal and distal ends of the sheath. Optionally, the expandable sheath assembly may include a vasodilator needle. The expandable sheath assembly (including the sheath body, dilator assembly, and optional vasodilator needle) is particularly superior to existing expandable sheath assemblies for patients with coronary artery disease (CAD) and peripheral artery disease, exhibiting arterial calcification and tortuosity that makes delivery of guide sheaths and catheters difficult. The expandable sheath assembly of this invention is easier to insert than conventional assemblies due to its reduced insertion profile, increased flexibility, reduced friction, and reduced risk of kinking under load. The reduced insertion profile minimizes insertion-related complications, minimizes stretching and load on the vascular orifice, and minimizes the risk of limb ischemia. The sheath body structure described herein provides sufficient axial rigidity in terms of maneuverability and flexural resistance, while maintaining bending flexibility and kinking resistance, and reducing friction to prevent "finger trapping." Furthermore, by having a smooth inner surface—with a thin coating thickness—reducing the force required to expand the sheath (compared to the force required to expand a sheath with an unbiased coating), and / or by having a smooth outer surface reducing the risk of thrombosis during prolonged use, while allowing the sheath to expand and contract as needed and reducing friction between the sheath body and the device inserted through it, the structure of the sheath body described herein represents an improvement over existing guide sheath bodies. Moreover, the structure of the sheath body described herein, through its interfaces with the dilator assembly, allows the sheath body to be held in place for insertion into the body lumen by restraining or entrapping a portion of the sheath body in the longitudinal direction. This restraint or entrapment of the sheath body facilitates insertion of the expandable sheath body together with the dilator assembly without damaging the expandable sheath body or altering its properties.

[0036] The sheath body can expand between different states to accommodate a medical device. For example, the sheath body extends to a first, smaller diameter state for insertion and relaxes to a second, larger diameter state after reaching the desired position to allow a portion of the medical device to pass through the cavity, this portion having a larger lateral cross-sectional area than the cavity in the first state. In different configurations, the sheath further expands between a resting state when the sheath is in its desired position and a larger diameter state when the medical device passes through. In any configuration, the expandable sheath assembly described herein requires no additional components compared to a standard guide: no external balloon, no folds in the expandable sheath body, and no second sheath for delivery. This can be superior to existing expandable sheath assemblies—by simplifying the use of expandable sheath assemblies (e.g., requiring fewer steps and taking less time).

[0037] Furthermore, the instantaneous expansion of the sheath body from an elongated state to a relaxed state (or from a relaxed state to an expanded state) minimizes the size of the opening required when inserting the sheath into the patient's vascular system (e.g., arteriotomy). Minimizing the amount of time the sheath body is in the expanded state also minimizes damage to the vessel wall, as a smaller opening would be needed to accommodate the sheath body in a relaxed or constricted state, thus minimizing thrombotic occlusion of the vessel. The smaller opening also minimizes the time required to achieve hemostasis after removal of the medical device. This expandable sheath eliminates the need for conventional setups with multiple sheaths, such as dissection guide sheaths and repositioning sheaths for guiding medical devices (e.g., intracardiac heart pumps) into the vessel. This expandable sheath also allows for the use of such conventional setups in conjunction with these, if necessary. Once the expandable sheath is positioned in the opening of the patient's vessel, it maintains access to the vessel even after the medical device has been removed, should other medical procedures require such access. This improves the procedural efficiency of any medical procedure, as there is no need to re-establish alternative access or insert a second sheath into the same access site. By effectively combining the guide sheath and repositioning sheath into a single device, costs involved during medical procedures are reduced. Furthermore, since only a single sheath is needed to achieve vascular access for arterial thrombosis, bleeding involved during prolonged use of percutaneous medical devices such as heart pumps is reduced. The integration of the sheath body and dilator assembly with the vasodilator needle allows for drip-based hemostasis at the vascular opening. In some embodiments, the vasodilator needle may be a repositioning sheath, which also serves to control blood flow along the expandable sheath and minimize bleeding.

[0038] In addition, the expandable sheath assembly described in this paper is superior to existing expandable sheath assemblies because they maintain guidewire access throughout the procedure, allowing the user to remove the pump while the sheath is in place.

[0039] If the expandable sheath is kept axially stretched (pulled downwards) before insertion, it can be delivered into the patient with a smaller profile. This has the primary benefits of: i) pulling downwards to a small profile to minimize insertion-related complications (i.e., bleeding, vascular injury, high insertion force); and ii) maintaining a “soft” sheath body and momentary expansion for interaction at the arterial incision site, thereby allowing for small-hole closure and minimizing bleeding caused by vascular recoil during use.

[0040] Previous expandable sheath delivery systems required complex mechanisms to capture the sheath tip, lock the sheath to the sheath hub, and pull the sheath downwards. This required at least two user manipulations, which were generally device-specific. Because such delivery systems differed from "general" guide systems, they could potentially require specific training to use and could lead to misuse.

[0041] A typical guide system is packaged as a separate sheath, a separate expander, and accessories. The user typically removes the sheath and expander, and pre-rinses each individually with saline solution to remove air. The user then assembles the guide system by inserting the expander into the proximal end of the sheath. The guide assembly is now ready for use.

[0042] This article describes a modification to the sheath tip that allows it to be "locked" to the dilator via an "interlocking" feature. By locking the dilator to the sheath in this way, the expandable sheath guide assembly can be inserted into the patient like a conventional guide, while retaining the benefits of the aforementioned expandable guide sheath. This interlocking expandable guide sheath assembly is easier to manufacture and use than those described above because its operation is similar to that of a conventional guide sheath assembly.

[0043] Figure 1A sheath assembly 100 according to various aspects of the present technology is shown. The sheath assembly has a hub 110 that locks the sheath in place upon insertion. The hub 110 works in conjunction with a cap 120 to hold the sheath body 130 in place. The hub 110 also has brakes 112 (only one of which is visible) to assist in attaching the hub 110 to an expander hub 230, which is further described below. A butterfly / suture pad 140 is configured to assist in attaching the sheath assembly 100 to a patient (e.g., by suturing the assembly to the patient). It can be seen that the distal end of the sheath body 130 has a tapered sheath tip 150. The sheath tip 150 may have a straight taper, a convex taper, a concave taper, or a taper composed of one or more straight segments, convex segments, and / or concave segments. The sheath tip 150 may be of any suitable length. In some embodiments, the length of the sheath tip 150 may be between 0.1 mm and 5 mm. In this description, the proximal end of the assembly is at the hub / cap end, while the distal end is at the tip. Fluid can be guided into the assembly via the side arm passage 160, and the fluid inflow into the device can be controlled by the rotary valve 170. A hemostatic valve (not shown) may also be included within the hub 110, configured to prevent blood leakage outside the patient's body during insertion and / or removal of an intracardiac pump or other components. While any suitable hemostatic valve may be used, examples are described and exemplified in U.S. Provisional Application No. 62 / 935,300 (which is incorporated herein by reference). Furthermore, in some embodiments, the hub 110 may include a foam insert (not shown) positioned proximal to the hemostatic valve, which may be soaked in a lubricant such as silicone to lubricate the component as it is inserted through the foam and into the sheath body 130.

[0044] The expandable sheath body 130 includes at least a frame and a coating. The coating can be applied to the outer surface of the sheath body 130 to facilitate passage through the patient's body, a technique known as the outer-diameter biased approach. In some embodiments, the coating may be a polymer, such as those described above. Figure 8-Figure 1 The polymer material 312 shown and described. This outer diameter bias coating advantageously provides a smooth outer surface—reducing the risk of clumping and minimizing friction when the device is inserted through the expandable sheath. For example, the use of a smooth outer surface advantageously minimizes the risk of clumping formation on the surface of the expandable sheath body 130, and the corrugated inner surface minimizes the surface area of ​​the expandable sheath in contact with the device being pushed through, thereby minimizing the associated frictional forces. In some embodiments, the corrugated inner surface may be a woven material, as described above. Figure 8-Figure 10. The braided material 314 shown and described. In some embodiments, additional smooth coatings may be applied to the inner and / or outer surfaces of the sheath body 130, i.e., covering the polymer material 312 and / or the braided material 314. The outer diameter bias coating further advantageously provides a thin coating thickness and requires relatively less force to expand the sheath body 130 compared to the force required to expand a sheath having no bias coating. The outer diameter bias coating also advantageously allows the sheath frame to expand and contract as needed, i.e., the outer diameter bias coating does not fix the frame to a fixed diameter because the thin coating thickness prevents the coating from enclosing the frame portions where the frame elements intersect. For example, for braided elements with an over-under braid pattern and a braided frame with an outer diameter bias coating, the outer diameter bias coating is advantageously thin enough not to enclose the overlapping portions of the braided elements, i.e., the outer diameter coating does not extend to the braided elements located below other braided elements in the over-under braid pattern.

[0045] In some embodiments, the expandable sheath frame may have an expansion mechanism that assists in the expansion and / or contraction of the frame. For example, the strands of the braided sheath frame may be configured with biases for expansion and / or contraction from a rest position. According to some embodiments, the expansion mechanism allows the strands to slide relative to each other as the frame expands and contracts.

[0046] The expandable sheath body 130 and sheath tip 150 can be formed in a variety of ways, including using the configurations and manufacturing methods described in U.S. Patent Publication No. 2019 / 0247627A1 and / or U.S. Patent Publication No. 2018 / 0256859A1 (which are incorporated herein by reference). For example, the expandable sheath body 130 (and sheath tip 150) can be manufactured using thermal bonding or outer diameter offset impregnation, which provides a smooth outer surface to the sheath body 130 while maintaining its desired spring-like expandable properties. Specific details of the possible configurations of the sheath body 130 and methods of manufacturing thereof are included in the referenced publications and will not be repeated in full here.

[0047] By using the frame and coating assembly as described above and in the referenced application, the expandable sheath body 130 can expand and contract while resisting kinking. This allows the sheath body 130 to expand to allow insertion or retrieval of a medical device, and then return to its original shape after deformation. Furthermore, configuring the expandable sheath to be compatible with the dilator assembly and the catheter needle assembly facilitates the insertion and removal of the dilator and improves hemostatic performance. Advantageously, the combination of the dilator assembly, the expandable sheath, and the catheter needle provides a synergistic system that can be used relatively early in the procedure, such as in a catheterization laboratory, rather than later in the procedure (e.g., during surgery, when pump migration could have more serious consequences for the patient). Because the system can be used relatively early in the procedure, potential pump migration problems can be addressed earlier, and vascular injury can be reduced.

[0048] This expandable sheath body 130 also eliminates the need for the conventional setup of having multiple sheaths—such as a stripping guide sheath and a repositioning sheath for guiding a medical device (e.g., an intracardiac pump) to a vascular opening (e.g., arteriotomy). In this respect, after the expandable sheath body 130 is positioned, it maintains access to the blood vessel even after the medical device has been removed, should other medical procedures require such access. This improves the procedural efficiency of any medical procedure and simplifies the process of inserting components into the patient, as there is no need to strip the guide sheath for insertion of the repositioning sheath each time access to the vascular opening is required. Furthermore, since there is no need to remove the expandable guide sheath body 130 and replace it with a second repositioning sheath, the risk of premature tearing / stripping is essentially eliminated, and the risk of unintentionally (e.g., due to excessive force) moving the guided device is reduced or eliminated. Furthermore, the use of an expandable guide sheath allows for more accurate repositioning of the medical device because the expandable guide sheath is fixed in place once inserted, whereas inserting a separate repositioning sheath involves multiple steps, increasing the chance of unintentional movement of the medical device. Despite the foregoing, the expandable sheath described herein can still be used in conjunction with the repositioning sheath.

[0049] Figure 2 An expander assembly 200 according to various aspects of the present technology is shown. The expander assembly 200 has an expander hub 230 at its proximal end, an expander body 210, an interlocking device 240, and an expander tip 220 at its distal end. It can be seen that the expander tip 220 tapers towards its distal end to facilitate insertion into the patient's vascular system. The expander hub 230 is configured to engage the hub 110 of the sheath assembly 100, which is further described below.

[0050] Figure 3A and Figure 3BCross-sectional views and partial sectional views of a portion of the expander assembly 200 according to various aspects of the present technology are depicted. Figure 3A It is a cross-sectional side view showing how the interlocking device 240 is attached to the expander tip 220 and the expander body 210, while Figure 3B This is a sectional view of the near-field equidistant portion of the same assembly. For example... Figure 3A and Figure 3B In the example shown, the distal end of the interlocking device 240 is connected to the expander tip 220 via a flange 241. The flange 241 extends into the proximal end of the expander tip 220. In some embodiments, the expander tip 220 may be directly molded onto the flange 241. The proximal end of the interlocking device 240 is connected to the expander body 210 via a threaded connection. In this respect, the proximal end of the interlocking device has a threaded male connector 242, which is received by a corresponding threaded female connector 212 on the distal end of the expander body 210. The threaded male connector 242 and the threaded female connector 212 may have any suitable diameter, pitch, specification, etc. For example, the threaded male connector 242 and the threaded female connector 212 may use standard metric threads, such as M1, M2, etc. Moving from proximal to distal, the outer contour of the interlocking device 240 is defined by a tapered waist 246, which begins at or near the outer diameter of the expander body 210 and increases in diameter until it reaches a cylindrical section 247 of constant diameter. Continuing distally, the cylindrical section 247 is followed by a recess 245 with a smaller outer diameter, and a transition between the cylindrical section 247 and the recess 245 forms a gripping surface 244. The gripping surface 244 and the recess 245 are configured to engage with the step 316 of the sheath tip 150, as further described below. The lengths of the tapered waist 246, the cylindrical section 247, and the recess 245 can be any suitable length. In some embodiments, the length of the cylindrical section 247 can be between 0.5 mm and 20 mm. The proximal end of the expander tip 220 has a transition edge 222. The transition edge 222 can have any suitable profile and angle. For example, the transition edge 222 may be a chamfer or a combination of two or more flat edges at different angles, may be curved in a concave or convex direction, or may be composed of one or more straight segments, convex segments and / or concave segments.

[0051] The expander tip 220, interlocking device 240, and expander body 210 can be made of any suitable material. In some embodiments, the expander tip 220 may be formed of a flexible material such as polyether block amide (“PEBA”) with a Duroy hardness of 40D. In some embodiments, the expander tip 220 may be formed of other flexible materials such as PEBA, silicone, thermoplastic polyurethane (“TPU”), or thermoplastic elastomer (“TPE”) with other hardness grades. In some embodiments, the expander tip 220 may further include a hydrophilic smooth coating such as polyvinylpyrrolidone (“PVP”) or hyaluronic acid (“HA”), or a hydrophobic coating such as silicone or polytetrafluoroethylene (“PTFE”). In some embodiments, the expander tip 220 may be uncoated.

[0052] In some embodiments, the expander body 210 may be formed of a semi-rigid material such as PEBA with a Duroy hardness of 70D. In some embodiments, the expander body 210 may be other semi-rigid materials such as PEBA, polyethylene, polypropylene, or polyurethane with other hardness grades. In some embodiments, heat may be applied to the threaded female connector 212 of the expander body 210 to improve its tensile strength and torsional resistance.

[0053] In some embodiments, the interlocking device 240 may be formed of a rigid material such as 304 stainless steel. In some embodiments, the interlocking device 240 may be formed of other rigid metals such as 316 stainless steel, or rigid polymers such as polyetheretherketone (“PEEK”), acrylonitrile-butadiene-styrene (“ABS”), or polycarbonate. In some embodiments, the interlocking device 240 may be wholly or partially coated, such as with a polymer. In some embodiments, the interlocking device 240 may have a coating with a thickness between 0.025 and 0.2 mm. In some embodiments, the interlocking device 240 may have a coating with a Duroy hardness between 40A and 70D. In some embodiments, the interlocking device 240 may have a coating with a coefficient of friction greater than that of stainless steel and / or a material selected for the expander tip 220 or expander body 210. In some embodiments, the interlocking device 240 may be uncoated.

[0054] Figure 4An isometric view of the expander hub 230 according to various aspects of the present technology is shown, with the housing 231 (comprising two halves) shown in partial cross-sectional view. It can be seen that the expander hub 230 has a toothed latch 250 that secures it to the hub 110 of the guide sheath assembly 100. The proximal end of the expander body 210 is coupled to an expander insertion mold 280. The expander insertion mold 280 has a flange 282 configured to engage with a spring 270 mounted within the proximal end of the expander hub 230. The spring 270 is configured to allow the expander insertion mold 280 to move in a proximal direction during attachment of the expander hub 230 to the hub 110 of the sheath assembly 100. In this respect, the spring stiffness of the spring 270 can be selected based on the elastic modulus of the sheath body 130 to optimize the amount of tension applied to the sheath body 130 when the expander hub 230 and hub 110 are pressed together and attached, and the sheath tip 150 is thus pulled in a distal direction. Similarly, spring 270 can be preloaded to a certain tension or compression to optimize the amount of tension applied to sheath body 130 when expander hub 230 and hub 110 are pressed together and attached. In this regard, in some embodiments, the spring stiffness of spring 270 can be between 0.1 N / mm and 3 N / mm, and its travel can be between 1 mm and 20 mm. In some embodiments, the force provided by the spring (including any preload) during attachment of expander hub 230 to hub 110 can be between 5 N and 30 N.

[0055] like Figure 4 As shown, the dilator hub 230 also has a lock 260 configured to engage with the dilator insertion mold 280. When engaged with the dilator insertion mold 280, the lock 260 prevents the dilator insertion mold 280 from moving in a proximal or distal direction. By preventing movement in the proximal direction, the lock 260 prevents the spring 270 from compressing when the dilator and sheath are inserted into the patient. Advantageously, by matching the spring stiffness and preload of the spring 270 to the elastic modulus of the sheath body 130, the sheath body 130 will be properly extended and tensioned when the dilator hub 230 is attached to the hub 110, so the lock 260 (after engagement) will hold the sheath body 130 at this desired point of extension and tension. The lock 260 is configured to automatically “close” or lock after the dilator hub 230 and sheath body 130 are attached. However, in some embodiments, the lock 260 may instead be configured such that it must be manually actuated, such as by a button or switch. Furthermore, since the tension of the sheath body 130 will naturally resist further movement of the expander body 210 in the distal direction, in some embodiments, the lock 260 may be configured to prevent movement only in the proximal direction.

[0056] Figure 5 yes Figure 4 Expander hub 230 along Figure 4The cross-sectional view is divided into plane AA. It can be seen that the lock 260 has teeth 261, while the expander insertion mold 280 has teeth 281. Figure 5 The display lock 260 is in the "open" position, allowing the expander insertion mold 280 to move within the expander hub 230. Although Figure 5 The toothed locking mechanism is shown, but the lock 260 can use any suitable mechanism to prevent the expansioner from moving into the mold 280.

[0057] Figure 6 It is in accordance with various aspects of this technology during the process of attaching the hub 110 to the sheath assembly 100 Figure 4 A cross-sectional side view of the expander hub 230. Figure 6 It can be seen that the toothed latches 250 of the expander hub 230 are all in the open position and have not yet engaged with the brake 112 in the hub 110. Similarly, the lock 260 is still shown in the "open" position, allowing the expander insert mold 280 to move within the expander hub 230. In this respect, the expander insert mold 280 shows that the spring 270 begins to compress in the proximal direction, as would occur when the expander hub 230 and hub 110 are pressed together and attached, and the sheath tip 150 is thus pulled in the distal direction.

[0058] Figure 7 An example is shown of various aspects of the present technology locked in the hub 110 of the sheath assembly 100. Figure 4 Expander hub 230. From Figure 7 As can be seen, the toothed latch 250 has engaged with the brake 112 in the hub 110, thus providing a clamping force to prevent the expander hub 230 from being pulled out of the hub 110. Furthermore, the lock 260 is shown in the "closed" position, where it has moved radially inward within the expander hub 230, such that its teeth 261 engage with the teeth 281 of the expander insertion mold 280. The engagement of teeth 261 and 281 provides resistance against further pushing of the expander insertion mold 280 into the expander hub 230 in the proximal direction. As discussed above, by adjusting the spring stiffness and preload of the spring 270 relative to the elastic modulus of the sheath body 130, the assembly can be configured such that the sheath body 130 reaches the desired tension, at which point the expander hub 230 is locked into the hub 110. Lock 260 can then be applied (e.g., manually or automatically, resulting in expander hub 230 locking into hub 110) to maintain sheath body 130 under desired tension and prevent expander insertion mold 280 from moving in the proximal direction when the expander and sheath are inserted into the patient.

[0059] Figure 8This is a cross-sectional side view of the distal end of the sheath assembly 100, showing an example of how the distal end of the sheath body 130 and the sheath tip 150 can be configured. The discussion will focus on three parts 302, 304, and 306. Figure 8 The structure is as follows. In the first portion 302, the sheath body 130 has a cavity 308 with an inner diameter 310. The outer surface of the first portion 302 is a polymer material 312. The inner surface of the first portion 302 is a braided material 314. The braided material 314 can be any suitable material as described above and in the referenced publications. In some embodiments, the braided material 314 may be composed of strands of a flexible metal such as nitinol. As mentioned above, in some embodiments, other smooth coatings (not shown) may be applied to the inner and / or outer surfaces of the sheath body 130, i.e., covering the polymer material 312 and / or the braided material 314. In some embodiments, the polymer material 312 is thermoplastic polyurethane (“TPU”) and is bonded to the braided material 314 using a thermoforming process. A step 316 exists between the first portion 302 and the second portion 304 on the inner surface of the sheath body 130. Step 316 forms an angle 324 with the inner surface of the first portion 302, creating a cavity 318, the second inner diameter 320 of which is smaller than the inner diameter 310 of the cavity 308. Figure 8 In the diagram, angle 324 is shown as a right angle, i.e., 90°. However, as further described below, angle 324 can be any angle that allows the step 316 to properly engage with the gripping surface 244 of the interlocking device 240. Therefore, in some embodiments, angle 324 can be an obtuse or acute angle (e.g., as described below regarding...). Figure 9 (Depicted and described). Step 316 can be of any suitable height. In some embodiments, step 316 can be between 0.1 mm and 1 mm.

[0060] In the second portion 304, the woven material 314 of the sheath tip 150 is sandwiched between polymer materials 312. As a result, the polymer material 312 forms both the inner and outer surfaces of the second portion 304. Furthermore, it can be seen that at the transition point from the sheath body 130 to the sheath tip 150, the outer surface begins to taper in diameter. This taper begins near the distal end of the first portion 302, and the tapering shape continues through the second portion 304 and the third portion 306. Similarly, the woven material 314 also has both cylindrical and tapered sections. Figure 8 As shown, the tapered section of the braided material 314 begins at the division between the first portion 302 and the second portion 304. However, in other embodiments, the tapered section of the braided material 314 can be larger than... Figure 8 It begins at a closer point (i.e., somewhere within the first part 302) or a farther point (i.e., somewhere within the second part 304 or the third part 306) shown in the image.

[0061] In the third part 306, the sheath tip 150 is entirely composed of polymer material 312. For example... Figure 8 As shown, the inner surface of the third part 306 has a transition edge 322 at its distal end. The transition edge 322 is as follows... Figure 8 The transition edge 322 is shown as a chamfer. However, the transition edge 322 can be a rounded corner or any other suitable profile. Furthermore, the transition edge 322 is optional. Thus, in some embodiments, the third portion 306 may have a constant inner diameter equal to the inner diameter 320, and the transition edge 322 may be replaced with a squared corner.

[0062] In some embodiments, the surfaces of the cavity 318 and / or transition edge 322 may be textured, or otherwise configured to reduce friction and static resistance between those surfaces of the sheath tip 150 and other devices passing through it, such as the dilator tip 220, interlocking device 240, interventional devices guided through the sheath assembly 100, such as intracardiac pumps, etc. Texture can be applied to the surfaces of the cavity 318 and / or transition edge 322 by any suitable method. For example, texture—which is formed by using a mandrel—can be applied to the sheath tip 150, the mandrel itself having been textured by machining, sandblasting, shot peening, chemical etching, laser surface texturing, etc. In this regard, in some instances, the surfaces of the cavity 318 and / or transition edge 322 may be mesh-like, embossed, or recessed. In some instances, the surfaces of the cavity 318 and / or transition edge 322 may have a pattern consisting of dashed or continuous lines that can extend in any direction, such as longitudinal, circumferential, or at any angle therein. In some instances, the surfaces of cavity 318 and / or transition edge 322 may have a line pattern, which may be curved, sinusoidal, serrated, or any combination thereof, and may extend in any direction, such as longitudinal, circumferential, or at any angle therein. In some instances, the surfaces of cavity 318 and / or transition edge 322 may have one or more raised or recessed grooves, which may extend in any direction, such as longitudinal, circumferential, or at any angle therein. Similarly, in some instances, the surfaces of cavity 318 and / or transition edge 322 may be coated with or constituted by a material that reduces friction or static resistance. For example, the surfaces of cavity 318 and / or transition edge 322 may have a smooth coating, or the polymer material 312 may be a material with a suitable low coefficient of friction, such as PTFE. The surfaces of cavity 318 and / or transition edge 322 may incorporate any combination of the different options described above, including textured features and combinations of smooth coatings and / or low-friction materials.

[0063] Figure 9This is a cross-sectional side view of the distal end of the sheath assembly 100, showing other examples of how the distal end of the sheath body 130 and the sheath tip 150 can be configured. Except for the transition between inner diameters 310 and 320, Figure 9 All features of the implementation method are related to Figure 8 The features shown are the same. In this respect, in Figure 9 In this context, the angle 324 between the inner surface of the first portion 302 and the step 316 is an acute angle, i.e., less than 90°. Similarly, as further described below, angle 324 can be any angle that allows proper engagement of the step 316 with the gripping surface 244 of the interlocking device 240. For example, in some embodiments, angle 324 can be an acute angle, such as between 30° and 89°.

[0064] Figure 10A This is a cross-sectional view of an embodiment of the expander body 210, interlocking device 240, and expander tip 220 according to various aspects of the present technology. Figure 10B Examples with Figure 8 The sheath tip 150 is engaged Figure 10A A myopic cross-sectional view of the component. Figure 10A and Figure 10B A generalized implementation is shown, in which the flange 241 and threaded male connector 242 of the interlocking device 240 and the threaded female connector 212 of the expander body 210 have been omitted. Those skilled in the art will understand that the expander body 210, the interlocking device 240, and the expander tip 220 can be coupled to each other in various ways, including but not limited to the above. Figure 3A and Figure 3B The method shown in the diagram. In this respect, the expander body 210, interlocking device 240, and expander tip 220 can be joined, bonded, or welded together. Similarly, the expander body 210, interlocking device 240, and expander tip 220 can be coupled using other fasteners. In some embodiments, one or more of the expander body 210, interlocking device 240, and expander tip 220 can be formed as a single structure or joined due to secondary injection molding. To obtain Figure 10B In the assembly, the expander tip 220 is pushed through the distal end of the sheath tip 150. As discussed above, the sheath tip 150 can be configured to expand as the tapered expander tip 220 passes through it. Thus, the sheath tip 150 can be configured such that it must expand to allow the transition edge 222 of the expander tip 220 to pass through, and then naturally contract again upon reaching the narrower recess 245 of the interlocking device 240. As the expander tip 220 continues to be pushed distally, the step 316 of the sheath tip 150 will contact the gripping surface 244 of the interlocking device 240, as... Figure 10BAs shown in the diagram, the gripping surface 244 intersects the surface of the recess 245 at an angle 248. Like angle 324, the described angle 248 can be any angle that allows proper engagement between the step 316 and the gripping surface 244 of the interlocking device 240. Therefore, in some embodiments, angle 248 can be a right angle. In some embodiments, angle 248 can be an acute angle, for example, between 30° and 89°. In some embodiments, angle 248 can be an obtuse angle. In some embodiments, angle 248 can differ from angle 324, as shown in the diagram. Figure 10B As in the example. In some embodiments, angle 248 may be the same as or substantially the same as angle 324, such as... Figure 11 As in the example, it provides... Figure 10A Components and Figure 9 A myopic cross-sectional view of the sheath tip 150 joint. (Except for...) Figure 11 In the implementation method, angle 248 is the same as or substantially the same as angle 324. Figure 11 All features of the implementation method are related to Figure 10B The features shown are the same.

[0065] like Figure 10B and Figure 11 As shown, after the interlocking device 240's gripping surface 244 engages the step 316 of the sheath tip 150, further pushing the dilator tip 220 distally will pull the sheath tip 150, thus initiating tension in the sheath body 130, causing it to elongate and narrow. Pulling the sheath body 130 downward in this manner helps to reduce its insertion profile, which helps to minimize patient complications (e.g., bleeding, vascular injury, high insertion force). At this point, the dilator assembly 200 can be used to insert the sheath tip 150 and the sheath body 130 into the patient's vascular system.

[0066] After the sheath body 130 has been positioned within the patient's vascular system as needed, the dilator hub 230 can be unlocked from the hub 110 of the sheath assembly 100 by pressing the toothed latch 250 and pulling the dilator hub 230 proximally. By continuing to retract the dilator assembly 200 proximally while the sheath tip 150 remains stationary, the grab surface 244 will be pulled away from the step 316, and the transition edge 222 of the dilator tip 220 will move past the sheath tip 150, allowing the dilator assembly 220 to be fully retracted from the patient. The sheath assembly 100 can then be used to guide an intracardiac pump and / or other components into the patient's vascular system, as discussed further above. Notably, since the sheath body 130 will no longer be under tension after the dilator assembly 200 is withdrawn, the sheath body 130 will be free to relax into a shorter and wider configuration to facilitate the insertion of such components.

[0067] From the foregoing and with reference to the accompanying drawings, those skilled in the art will understand that certain modifications may be made to this disclosure without departing from its scope. While several embodiments of this disclosure have been shown in the drawings, it is intended that the disclosure be limited thereto, just as it is intended to be as broad as would be permissible in the art, and the specification should be read in the same manner. Therefore, the foregoing description should not be construed as limiting, but merely as examples of specific embodiments. Other modifications will be contemplated by those skilled in the art within the scope and spirit of the appended claims.

Claims

1. A medical guidance device, comprising: An expandable sheath, the expandable sheath comprising: An expandable frame in the shape of a cylinder or substantially cylinder, the expandable frame having a proximal opening, a distal opening, an inner surface, and an outer surface; and The material covers a portion of the inner surface of the expandable frame and the outer surface of the expandable frame, and forms a stepped feature within the distal opening, the stepped feature having a first surface adjacent to the inner surface of the expandable frame and oriented at a first angle relative to the inner surface of the expandable frame. Expander, the expander comprising: A cylindrical or substantially cylindrical body; Conical tip; and The interlocking device between the body and the conical tip includes: a first cylindrical section having a first outer diameter; a second cylindrical section having a second outer diameter smaller than the first outer diameter; and a gripping surface adjacent to the first cylindrical section and oriented at a second angle relative to the first cylindrical section; and The expander is configured to be inserted into the expandable sheath through a proximal opening in the expandable frame; and The gripping surface is configured to engage the first surface to prevent the body of the expander from passing through the distal opening from the expandable frame.

2. The device according to claim 1, further comprising: A sheath hub, configured to secure the expandable sheath near a proximal opening of the expandable frame; and Expander hub, the expander hub comprising: An expander is inserted into a mold, the expander insertion mold being configured to secure the body of the expander; A spring configured to engage the expander insertion mold and prevent movement of the expander insertion mold within the expander hub; and One or more latches are configured to lock the expander hub to the sheath hub.

3. The device according to claim 1, wherein the gripping surface is a conical gripping surface.

4. The device of claim 3, wherein the tapered gripping surface is configured to engage a portion of the material near the distal opening of the expandable frame.

5. The device according to claim 1, wherein the first angle is 90 degrees.

6. The device according to claim 1, wherein the first angle is less than 90 degrees.

7. The device according to claim 1, wherein the second angle is 90 degrees.

8. The device according to claim 1, wherein the second angle is less than 90 degrees.

9. The device according to claim 1, wherein the radial height of the stepped feature is between 0.1 mm and 5 mm.

10. The device according to claim 1, wherein the material is a polymer.

11. The device of claim 10, wherein the material is thermoplastic polyurethane.

12. The device of claim 1, wherein the expandable frame is a woven material.

13. The device of claim 12, wherein the braiding material comprises strands of nitinol.

14. The device of claim 1, wherein the expandable sheath further comprises a coating applied to the expandable frame and the material.

15. The device of claim 14, wherein the coating is a smooth coating.

16. The device according to claim 1, wherein the interlocking device is made of stainless steel.

17. The device of claim 16, wherein the interlocking device is coated with a polymer.

18. The device according to claim 1, wherein the interlocking device is formed of a polymer.

19. The device of claim 1, wherein the tapered tip is formed of a polymer.

20. The device of claim 18, wherein the conical tip is formed of polyether block amide.

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