Vessel dilator with rigid section
By introducing a design with variable bending stiffness and a high-rigidity section into the vascular dilator, the problem of separation between the guide sheath and the dilator at sharp turns is solved, enabling safer vascular access establishment.
Patent Information
- Application Number
- CN202480072476.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-11-17
- Filing Date
- 2024-11-18
- Publication Date
- 2026-07-07
AI Technical Summary
Existing vasodilators and guide sheaths are prone to separation when making sharp turns, resulting in gaps between the distal end of the guide sheath and the end of the dilator, which may scrape the arterial wall. Furthermore, it is difficult to maintain a tight fit between the layers of multi-layer guide sheaths.
Design a vascular dilator with variable bending stiffness along its length, especially with a high-rigidity section between the distal and proximal ends to reduce bending, and reinforce the rigid section with support elements such as metal tube inserts or braided structures to ensure a smooth transition between the guide sheath and the dilator.
It effectively reduces the gap between the guide sheath and the dilator, lowers the risk of trauma to blood vessels, and improves the stability and safety of navigation through sharp turns.
Smart Images
Figure CN122349437A_ABST
Abstract
Description
Technical Field
[0001] This technical field generally relates to vasodilators and guide sheaths and their components for insertion into the body to provide endovascular access to a variety of medical devices. This includes, but is not limited to, all arterial and vascular system access, abdominal and thoracic cavities, brain and spinal cord, genitourinary and gynecological, upper gastrointestinal and colorectal surgeries. Background Technology
[0002] Vascular access devices (including vascular guide sheaths and vascular dilators) are now very common in many endovascular procedures, such as transcatheter aortic valve replacement (TAVR), angioplasty, and stent placement. Vascular access devices typically facilitate access to the vascular system for the introduction of removable devices (such as wires, balloons, and pressure transducers) and for the introduction and placement of implantable devices (such as mechanical aortic valves and stents).
[0003] Vascular access devices are now typically inserted percutaneously into a patient's blood vessels. The practice of avoiding scalpel incisions to expose blood vessels for insertion has made the use of vascular access devices safer and more frequent. Percutaneous insertion involves inserting a needle or similar puncture device into the skin without first cutting the skin to expose the vessel. The vascular access device is advanced through the skin and inserted into the blood vessel via a puncture. For the patient, percutaneous techniques reduce blood loss and the likelihood of human error that can occur with scalpel incisions, and shorten recovery time.
[0004] During percutaneous surgery, the guide sheath is typically positioned at the entry point into the patient's blood vessel and pushed through the vessel until it is firmly seated in the patient's body where it is needed. The proximal end of the guide sheath protrudes outside the patient's body to provide an entry point for subsequent insertion of other endovascular devices. Often, a dilator is placed inside the guide sheath and pushed through the vessel opening together with the guide sheath to gradually open the puncture site and allow the guide sheath to enter while minimizing vascular trauma.
[0005] The percutaneous entry point is typically much smaller than the diameter of the guide sheath, and may require considerable force to stretch the patient's skin at the percutaneous opening to deliver the vascular access device into the blood vessel. Therefore, any device with grooves, notches, or angular edges can create a choking point, where the skin may become stuck and tear, resulting in site trauma and delayed recovery for the patient. Consequently, a typical guide sheath has a tapered distal end to provide a smooth transition to the dilator tip and endcap when used to open the vascular system, allowing the guide sheath to enter without excessive trauma.
[0006] Guide sheath assemblies exist in many different forms. According to a particular category of assembly, a guide sheath assembly has a guide sheath and a vasodilator with an enlarged end mounted on a flexible shaft, which may be in the form of an elongated tube. The outer diameter of the flexible shaft is smaller than that of the dilator end and also smaller than the inner diameter of the guide sheath. The size of the dilator end corresponds in diameter to the outer diameter of the guide sheath at the point where the dilator end engages with the guide sheath. This ensures a smooth transition between the guide sheath and the dilator end. Such an assembly is disclosed in PCT / AU2019 / 051010, the contents of which are incorporated herein by reference in their entirety. Ideally, to avoid trauma, any transition between the dilator end and the distal end of the guide sheath should be 0.1 mm or less. However, this is not always achievable, especially due to manufacturing variations. Depending on the specific guide sheath assembly, these variations may become more critical, making it more difficult to avoid a larger transition. Furthermore, the distal end of the guide sheath is prone to detaching from the dilator tip during sharp turns, potentially creating a gap on the outer side of the turn between the distal end of the guide sheath and the adjacent end of the dilator tip. This creates a potential hazard that the tip of the guide sheath may scrape the arterial wall during delivery through tortuous anatomical structures. The distal end of the guide sheath also needs to expand and retract easily, making it difficult to maintain axial alignment between the distal end and the dilator tip.
[0007] Current marketed guide sheaths (including inflatable guide sheaths) have a constant-diameter dilator / guide, with the distal end of the guide sheath tapering to minimize steps. This allows the guide sheath to maintain a tight fit with the dilator and avoids edge irritation to the artery. However, not all types of guide sheaths and dilators achieve this. For guide sheaths with multiple layers, the presence of multiple layers and the relative movement between these layers make achieving the aforementioned fit difficult (if possible). Summary of the Invention
[0008] Each aspect of this disclosure addresses at least the aforementioned problems and / or shortcomings, and provides at least the advantages described below.
[0009] In a first aspect, a vascular dilator according to claim 1 is provided. The vascular dilator has variable bending stiffness along its length, particularly provided by a relatively high-stiffness section bridging the distal end of the elongated tube and the proximal end of the dilator tip. Therefore, the majority of the dilator remains relatively flexible. This configuration is designed to reduce the amount of bending of the vascular dilator at the rigid section locations, thereby reducing the gap between the guide sheath and the vascular dilator when navigating around sharp turns. In embodiments, the variable bending stiffness may appear as a step change or gradually transition along the length of the elongated tube.
[0010] As used herein, the terms “proximal” and “distal” should be understood as terms opposite to the direction of use of the article they refer to. The term “distal” should be understood as the end of the article that first enters the patient, while the term “proximal” should be understood as the end opposite to the “distal” end. For example, the “distal end” may be closest to the dilator tip, such that in use, the distal end is closest to the patient and the proximal end is closest to the user.
[0011] The terms "distal end" or "proximal end" are intended to indicate a region rather than a specific point, such as the area where the tube or dilator tip terminates. To avoid ambiguity, the most proximal or most distal end of the tube or dilator tip will be referred to as the proximal or distal end. Therefore, the term "outside the rigid segment" is intended to refer to the vasodilator region adjacent to and located proximal and / or distal to the rigid segment. Subsequently, the region "outside the rigid segment" can also be located at the tip of the tube and / or dilator.
[0012] Those skilled in the art will recognize that, particularly in vascular dilators with enlarged dilator tips, the bending stiffness at the proximal end of the dilator tip may already be relatively higher than that of the elongated tube due to factors such as increased thickness and / or diameter. Therefore, the difference in bending stiffness between the rigid section and the elongated tube adjacent to the rigid section can be greater than the difference in bending stiffness between the rigid section and the dilator tip. Thus, the rigid section can also provide reinforcement at least to the distal end of the elongated tube. In embodiments, the rigid section typically covers 2 mm to 20 mm of the distal end of the elongated tube and 2 mm to 20 mm of the proximal end of the dilator tip.
[0013] In embodiments, the rigid section may include one or more support elements comprising at least one of the following: a metal tube insert in the lumen of the elongated tube; a metal tube insert on the outer diameter of the elongated tube; a braided or wound reinforcement structure in the lumen or on the outer diameter of the elongated tube; different polymers for the central elongated tube section and the distal end; a polymer in which reinforcing additives (e.g., carbon fiber, glass fiber, mineral additives, talc, etc.) are dispersed; or the reinforcing section and / or the rigid section may involve a variation in the outer diameter of the elongated tube, for example, the diameter at the distal end is larger than the diameter at the central section.
[0014] Preferably, the one or more support elements are formed of a semi-rigid material. The term "semi-rigid" is to be understood herein as defining a material or structure that is flexible to some extent but has a certain degree of stiffness or rigidity, as opposed to being completely flexible or completely rigid. In some embodiments, the length of the one or more support elements is from 2.0 mm to 40.0 mm, preferably from 4.0 mm to 20.0 mm. In other embodiments, the length of the one or more support elements is preferably from 40.0 mm to 120.0 mm, preferably from 50.0 mm to 100.0 mm.
[0015] In one embodiment, the vasodilator includes a dilator hub attached to the proximal end of an elongated tube, preferably for attachment to a guide sheath. In another embodiment, the dilator hub includes a fixing member configured for attachment to a guide sheath.
[0016] The term "layer" as used herein should be understood as a sheet or similar form of construction that can partially or completely cover another article or object. The term "layer" should not be overly limited in its construction to imply the presence of one or more other layers, articles, or objects. For example, an article may include two or more layers that may be joined at their edges rather than laminated or delaminated, and may still be considered two separate layers in their own nature.
[0017] In another aspect of this disclosure, a vascular dilator assembly is provided, comprising a guide sheath and a vascular dilator according to the first aspect. The length of the guide sheath is arranged such that when the vascular dilator is introduced into the guide sheath, the distal end of the guide sheath is aligned with the proximal end of the dilator tip of the vascular dilator.
[0018] Due to the rigidity of the vasodilator's section, the point of maximum bending of the elongated tube can be located away from the attachment point between the dilator tip and the elongated tube, closer to the distal end of the elongated tube. Therefore, when the dilator tip and guide sheath assembly are making a sharp turn, this point of maximum bending will be located inside the guide sheath, minimizing any gaps that may arise outside the turn between the distal end of the guide sheath and the adjacent end of the dilator tip. The guide sheath and vasodilator can have any suitable connecting members at their proximal ends to provide a connection between the guide sheath and the vasodilator and prevent further relative movement between them. As previously described, the vasodilator may include an dilator hub attached to the elongated tube at its proximal end, and the dilator hub may include a fixing member configured for attachment to the guide sheath.
[0019] In an embodiment, the guide sheath may further include an annular collar, which preferably includes a fixing fitting configured to receive a fixing member and secure the vasodilator to the fixing member.
[0020] In another aspect of this disclosure, a vascular dilator is provided, comprising an dilator shaft, a dilator tip, and a dilator lumen extending through the dilator shaft and the dilator tip; wherein the dilator shaft includes a distal end comprising a reinforcing section and a connecting section, wherein the bending stiffness of the reinforcing section is higher than the average bending stiffness of the remaining portion of the dilator shaft distal to the reinforcing section; the connecting section engages within the cavity of the dilator tip; and wherein the dilator tip tapers gradually from a maximum diameter near the dilator shaft to the distal end of the dilator tip.
[0021] In an embodiment, the cross-section of the remainder of the expander shaft may be substantially uniform and may have a first uniform bending stiffness along its length. The reinforced section may have a second bending stiffness that is slightly greater than or significantly greater than the second bending stiffness of the expander shaft. The second bending stiffness may be at least 5% or 10% greater than the first bending stiffness. Attached Figure Description
[0022] The invention will now be explained in more detail with reference to the accompanying drawings, in which several illustrative embodiments of the invention are shown. These illustrative embodiments are intended for illustrative purposes only and are not intended to limit the inventive concept as defined by the appended claims.
[0023] Figure 1 A front view of a prior art vascular dilator assembly is provided, showing the prior art guide sheath and collar in a dashed transparent manner. Detail A provides a detailed view of part A.
[0024] Figure 2 A side-view perspective of the vasodilator is provided. Detail B provides an enlarged view of the vasodilator tip.
[0025] Figure 3 A side-view exploded stereoscopic view of the vasodilator and guide sheath assembly is provided.
[0026] Figure 4 A longitudinal section of a vascular dilator according to a first embodiment of the present invention is provided.
[0027] Figure 5 A longitudinal section of a portion of a vascular dilator according to a second embodiment of the present invention is provided.
[0028] Figure 6 A longitudinal section of a portion of a vascular dilator according to a third embodiment of the present invention is provided.
[0029] Figure 7 A longitudinal section of a portion of a vascular dilator according to a fourth embodiment of the present invention is provided.
[0030] Figure 8 A front view of a portion of a vascular dilator according to a fifth embodiment of the present invention is provided.
[0031] Figure 9 A front view of a portion of a vascular dilator according to a sixth embodiment of the present invention is provided.
[0032] Figure 10A A longitudinal section of a portion of a vascular dilator according to a seventh embodiment of the present invention is provided. Figure 10B and Figure 10C The transverse sections of the vasodilator are provided at the distal end of the slender tube and at the proximal end of the dilator tip.
[0033] Figure 11 A longitudinal section of a portion of a vascular dilator according to an eighth embodiment of the present invention is provided.
[0034] Figure 1 A front view of a prior art vascular dilator assembly is provided, showing the prior art guide sheath 150 in a dashed transparent manner. Detail A provides an enlarged front view of the dilator tip 130 and the guide sheath 150. The vascular dilator 100 is a tubular device for insertion into a vascular opening to reduce trauma while dilating the vessel for introduction of the guide sheath 150.
[0035] In many prior art vasodilator and guide sheath assemblies of this type, the lengths of both the vasodilator 100 and the guide sheath 150 are designed such that when the dilator hub 110 is attached to the collar 151, the distal end 153 of the sleeve 152 of the guide sheath 150 is nominally positioned to contact the proximal end of the dilator tip 130 to provide a substantially smooth transition between the distal end of the sleeve and the proximal end of the dilator tip.
[0036] Detail A shows detailed views of the distal end 153 of the sleeve 152 of the expander sheath 150 and the proximal end of the expander tip 130 of the expander 100. Although the design lengths of both the expander 100 and the expander sheath 150 nominally position the expander tip 130 at the distal end 153 of the sleeve 152, manufacturing errors in both the expander 100 and the expander sheath 150 may result in a gap 140 between them. The presence of gap 140 may impede a smooth transition between the expander tip 130 and the sleeve 152, and may cause skin and tissue to become stuck against the distal end 153 within gap 140.
[0037] Figure 2 A side perspective view of a vasodilator 300 is provided. The vasodilator 300 generally comprises an expander hub 310 at its proximal end 301, an expander tip 330 with a tapered head at its distal end 302, and an expander shaft 320 between the proximal and distal ends of the vasodilator. A lumen extending from the proximal end 301 to the distal end 302 of the vasodilator 300 allows wires and small instruments to pass through it. The diameter of the lumen is from 0.3 mm to 3.0 mm, preferably from 1.0 mm to 2.0 mm.
[0038] The dilator hub 310 provides an attachment point for a guide sheath (not shown) and allows an operator to manipulate the dilator 300 during insertion of the dilator into the guide sheath. The dilator hub 310 is a rigid annular structure having a larger diameter portion 311 and a smaller diameter portion 312. The smaller diameter portion 312 is shaped to fit within a guide sheath collar. The dilator hub 310 further includes: a retaining member implemented herein as a bayonet fitting 313 formed on the surface of the smaller diameter portion 312 of the dilator hub 310 body; and a button 340 slidably inserted into the larger diameter portion 311 of the dilator hub 310 and coupled to the larger diameter portion via a biasing element (not shown) implemented as a spring, one end of which is attached to the button 340 and the other end of which is attached to the dilator hub 310.
[0039] The dilator hub 310, button 340, dilator shaft 320, and dilator tip 330 all have lumens passing through them, allowing wires and small instruments to be delivered to the blood vessel. Detail B provides details of the dilator tip 330 and guide sheath. The dilator tip 330 is generally conical or arrowhead shaped, and its diameter gradually increases from the distal end diameter of the dilator shaft 320 (at the interface 331 between the dilator tip 330 and the dilator shaft 320) to the maximum diameter of the dilator tip 330, and gradually tapers from the maximum diameter of the dilator tip 330 to the rounded apex at the distal end of the dilator tip 330. In this way, the interface 331 prevents abrupt changes in diameter between the dilator shaft 320 and the dilator tip 330. The dilator shaft 320 is substantially cylindrical and attaches to the dilator tip 330 at its distal end and enters the dilator hub 310 at its proximal end, where the dilator shaft is attached to a button 340. The connection between the button 340 and the biasing element allows the dilator shaft 320 to move longitudinally slidably relative to the dilator hub 310. Thus, starting from a uniform diameter of the dilator shaft 320, the diameter of the vascular dilator 300 increases at the interface 331, creating a smooth, sloping transition toward the maximum diameter of the dilator tip 330. The dilator tip 330 reaches its maximum diameter after the interface 331. From this maximum diameter, the dilator tip 330 tapers gradually toward a rounded apex at its distal end. This configuration minimizes the abrupt transition between the dilator shaft 320 and the dilator tip 330. The length of the interface 331 is from 0.5 mm to 20.0 mm, preferably from 5.0 mm to 10.0 mm.
[0040] The expander shaft 320 includes an elongated tube 322 with an outer diameter of 2.0 mm to 7.0 mm and / or a length of 100.0 mm to 1100.0 mm. The expander end has an outer diameter of 4.0 mm to 12.0 mm. The maximum diameter of the expander end 330 (e.g., at its proximal end) is 1.1 to 2.5 times the outer diameter of the elongated tube 322. The length of the expander end 330 is 15 mm to 200 mm.
[0041] Figure 3An exploded side perspective view of components of a vasodilator 300 and guide sheath 40 assembly according to a preferred embodiment of the present invention is provided. The vasodilator 300 generally includes an dilator hub 310, a button 340, a retaining member 313, a biasing element implemented as a coil spring 350, a dilator shaft 320, and a dilator end 330. The dilator end 330 has a proximal end 332 configured to attach to a distal end 321 of the dilator shaft 320. The proximal end 332 of the dilator end 330 and the distal end 321 of the dilator shaft 320 can be attached by partially inserting the dilator shaft into the dilator end. The distal end 321 of the dilator shaft 320 and the proximal end 332 of the dilator tip 330 are adapted to form a reinforcing section and / or a rigid section of the vascular dilator 300, the bending stiffness of which is higher than the average bending stiffness of the vascular dilator 300 outside the rigid section.
[0042] The guide sheath 40 generally consists of two main components: a rigid annular collar 41 and a sleeve 42. The collar 41 is a hollow structure configured to allow material to be fed into the internal lumen of the sleeve 42 through a wider opening. The collar 41 is formed of a rigid material to allow the user to manipulate the collar 41 and pass an object or material through it. The collar 41 includes a retaining fitting 44 (implemented here as a bayonet-type receiving part) terminating at an opening shaped to allow the sleeve 42 to be placed and secured therein, thereby connecting the two components. After the expander 300 is inserted into the guide sheath 40, the expander hub 310 is securely attached to the collar 41 by engaging the retaining member 313 to the retaining fitting 44 to position the expander end 330 relative to the distal end 43 of the sleeve 42 and prevent further relative movement of the expander end. Technicians will recognize that other equivalent attachments and / or connecting members between the dilator hub and the collar can be used to secure the vasodilator 300 and the guide sheath 40 to each other.
[0043] Figure 4 A longitudinal section of a vascular dilator 400 according to a first embodiment of the present invention is provided. As previously described, the vascular dilator 400 includes a dilator end 430 and a dilator shaft 420. The dilator shaft 420 includes an elongated tube 422 that includes a dilator shaft lumen 424 extending throughout its entire length. The dilator end 430 further includes a dilator end lumen 431 extending throughout its entire length. When the dilator end 430 is connected to the elongated tube 422, the lumens of the two overlap to form a vascular dilator lumen that extends through the vascular dilator from a proximal end to a distal end of the vascular dilator 400.
[0044] The vasodilator 400 further includes a support element 450 located at the distal end 421 and extending to the end of the elongated tube 422. The support element 450 comprises a tube or tubular insert made of metal or polymer material and placed on the outer surface of the elongated tube 422. The proximal end 432 of the dilator end 430 includes an opening 433 providing passage to a cavity 434, the diameter of which is larger than the diameter of the lumen 431. The cavity 434 is configured to partially receive the distal end 421 of the elongated tube 422. In the depicted embodiment, the cavity 434 is further configured to receive the support element 450 placed on the elongated tube 422. Because the support element 450 is located at the distal end 421 of the elongated tube 422 and the proximal end 432 of the dilator end 430, the support element 450 provides a reinforcing structure for the vasodilator, thereby giving this segment of the vasodilator 400 higher flexural stiffness. This is also referred to here as the reinforcing and / or rigid segment of the vasodilator 400.
[0045] Figure 5 to Figure 11 Cross-sections of a vascular dilator according to several embodiments of the present invention are shown. Features previously described with reference to the first embodiment may also exist in another embodiment, and will not be repeated here for the sake of brevity. Figure 5 to Figure 11 In the figures, similar features are indicated by reference numerals starting with 500, 600, 700, etc., to distinguish the embodiments.
[0046] Figure 5 A longitudinal section of a portion of a vasodilator according to a second embodiment of the invention is provided. The vasodilator 500 includes a support element 550 disposed within the inner diameter of a distal end 521 and extending to the end of an elongated tube 522. The support element 550 comprises a tube or tubular insert made of a metal or polymer material and disposed within a lumen 524 of the elongated tube 522. This configuration ensures that the support element 550 is located at the outer diameter of the lumen 524, thereby providing support from within the elongated tube 522.
[0047] Similar to the first embodiment, the proximal end 532 of the dilator tip 530 includes an opening 533 that provides access to a cavity 534. The cavity 534 is configured to partially receive the distal end 521 of the elongated tube 522 and a support element 550 disposed within the elongated tube. Because the support element 550 is located at the distal end 521 of the elongated tube 522 and the proximal end 532 of the dilator tip 530, it provides a reinforcing structure to the vasodilator, thereby providing greater flexural stiffness to this segment of the vasodilator 500 from within the elongated tube 522, thus providing a rigid segment for the vasodilator 500.
[0048] Figure 6A longitudinal section of a portion of a vasodilator according to a third embodiment of the invention is provided. The vasodilator 600 includes a support element 650 embedded within the sidewall 625 of an elongated tube 622, starting from a distal end 621 and extending to the tip of the elongated tube 622. Similar to previous embodiments, the support element 650 is a tube or tubular insert made of a metallic or polymeric material. The support element 650 is integrated into the sidewall 624 of the elongated tube 622, thereby providing internal reinforcement without occupying the lumen 624. Since the support element 650 is located at the distal end 621 of the elongated tube 622 and the proximal end 632 of the dilator tip 630, the support element 650 provides a reinforcing structure for the vasodilator, thereby creating a reinforced region and / or a rigid segment. Integrating the support element 650 into the sidewall 625 can be achieved by removing material from the sidewall to form a recess for receiving the support element 650 or by a lamination or reflow process. For example, at least the distal end 621 of the elongated tube 622 can be formed by placing a support element 650 around an inner tube and then placing an outer tube around the support element 650. Subsequently, the inner tube, support element 650, and outer tube can be integrally bonded by reflow / lamination and / or fusion. Material on the outer tube can be partially removed to achieve a continuous outer diameter between the outer tube and the elongated tube 622.
[0049] Figure 7 A longitudinal section of a portion of a vascular dilator according to a fourth embodiment of the invention is provided. The vascular dilator 700 includes a support element 750 extending from the distal end 721 of an elongated tube 722 beyond the end of the elongated tube 722 and into a dilator end 730. However, the support element 750 may also extend to the end of the elongated tube 722 to provide similar reinforcement. The support element 750 includes a hollow insert made of a polymeric material having relatively high stiffness compared to the stiffness of the elongated tube 722 and the dilator end 731. Alternatively, the polymeric material of the insert may have a stiffness similar to that of the elongated tube 722 and / or the dilator end 731 and includes reinforcing additives to increase its stiffness. The support element 750 is positioned between the dilator end 730 and the elongated tube 722. The support element 750 includes a first segment 751 and a second segment 752. The first segment is disposed inside the expander end 730, and the second segment is preferably integrally formed with the first segment 751 and disposed outside the expander end 730 and on the outer surface of the distal end 721 of the elongated tube 722. The expander end 730 includes a cavity 734 within the proximal end 732 of the expander end 730, the cavity being configured to receive the first segment 751 of the support element 750.
[0050] The first section 751 of the support element 750 substantially follows the shape of the cavity 734, such that the first section fits snugly within the expander end 730. The first section 751 of the support element 750 further includes a lumen 737, which coincides with the lumen 731 of the expander end 730 and the lumen 724 of the elongated tube 722 when the expander end 730, the elongated tube 722, and the support element are assembled together.
[0051] A second segment 752 of the support element 750 extends from the proximal end 732 of the dilator tip 730 and partially covers the distal end 721 of the elongated tube 722. The support element 750 further includes an opening 753 at the proximal end of the second segment 752, which provides passage to a cavity 736 with a diameter larger than that of the lumen 737. The cavity 736 is configured to partially receive the distal end 721 of the elongated tube 722. The support element 750 (particularly in combination with the elongated tube 722) has a higher bending stiffness in the central and / or proximal segments than the elongated tube 722. Because the support element 750 is on the distal end 721 of the elongated tube 722 and within the proximal end 732 of the dilator tip 730, the support element 750 provides higher bending stiffness to this segment of the vasodilator 700, thereby forming a reinforcing and / or rigid segment of the vasodilator 700.
[0052] Figure 8 A front view of a portion of a vascular dilator 800 according to a fifth embodiment of the invention is provided. The vascular dilator 800 includes a support element 850 configured to reinforce the distal end 821 of an elongated tube 822, thereby providing a reinforcing structure, i.e., higher stiffness, specifically for that section of the elongated tube 822. In the depicted embodiment, a coiled reinforcement structure is provided by the support element 850, which includes a coil (e.g., a wire coil) positioned on the outer surface 825 of the elongated tube 822, partially covering the distal end 821 of the elongated tube 822. In other embodiments, the coil may be placed within the elongated tube 822.
[0053] The coil pitch increases proximally from the end of the elongated tube 822, thereby providing maximum stiffness at the distal end 821 of the elongated tube 822 to form a reinforcing and / or rigid section of the vasodilator 800. The cavity 834 of the dilator end 830 is configured to partially receive the distal end 821 of the elongated tube 822, which includes a portion of the distal end of the support element 850. This arrangement allows the bending stiffness to gradually decrease from the end of the elongated tube 822 toward the central section of the elongated tube 822. Reinforcement of the distal end 821 of the elongated tube 822 (similar to the reinforcement provided by the coil) can be achieved by reducing the cross-sectional area of the wire in the coil proximally. The support element 850 can be laminated, embedded, or adhered to the outer surface of the elongated tube 822. For example, in a lamination process, the outer diameter of the elongated tube 822 is partially melted to increase the contact surface with the support element 850 and to provide a geometry-locking structure as the outer diameter of the elongated tube cools. In another example, the coil can be embedded into the outer surface of the elongated tube 822 by applying radial pressure, thereby sinking the coil into the soft surface of the elongated tube 822 and increasing the geometry locking structure. Furthermore, other hollow structures (such as tubular braids, woven structures, or multi-layered structures) can achieve the same effect and can be applied using similar methods.
[0054] Figure 9 A front view of a vascular dilator 900 according to a sixth embodiment of the present invention is provided, showing in a transparent manner an elongated tube 922 and a dilator end 931. The distal end 921 of the elongated tube 922 includes three sub-segments: 921a, 921b, and 921c. Similar to the previously described embodiments, the proximal end 932 of the dilator end 930 is configured to receive the third sub-segment 921c within a cavity 934. The first sub-segments 921a and the third sub-segments 921c have lateral partial cuts in the circumferential direction of the sidewall of the elongated tube 922, thereby reducing the cross-sectional area of the elongated tube 922 at these sub-segments. The lateral partial cuts provide stress relief for the vascular dilator 900 at their locations. Therefore, the bending stiffness of the second sub-segment 921b is higher than that of the first sub-segments 921a and the third sub-segments 921c outside the second sub-segment 921b, thereby forming a rigid segment of the vascular dilator 900. The cut can be formed by laser cutting, mechanical cutting, or similar known methods. Similar modifications can also be made to the interior or exterior of the proximal end 932 of the expander end 930 (e.g., within the cavity 934).
[0055] Figure 10A A longitudinal section of a portion of a vascular dilator 1000 according to a seventh embodiment of the present invention is provided. Figure 10B and Figure 10CLateral sections of the vasodilator 1000 are provided at the distal end 1021 of the elongated tube 1022 and at the proximal end 1030 of the dilator tip 1000. The vasodilator 1000 includes a support element 1050 located at the distal end 1021 of the elongated tube 1022 and extending beyond the tip of the elongated tube 1022. The support element 1050 includes a trilobed insert. The trilobed insert 1050 has three lobes 1062 arranged in a circular manner and connected to each other by an annular base 1063.
[0056] The sidewall of the elongated tube 1022 is configured at its distal end 1021 to receive a leaf-shaped insert. In the depicted embodiment, the leaf-shaped insert is a trilobal insert; however, the insert may include a non-tubular portion or two, four, or more lobes or portions. The sidewall includes three recesses 1061 that extend longitudinally along the direction of the elongated tube 1022 and are embedded within the thickness of the sidewall. These recesses 1061 are circularly spaced around the circumference of the sidewall. The proximal end 1032 of the expander end 1030 is configured to partially receive the distal end 1021 of the elongated tube 1022 and the trilobal insert, thereby forming a reinforcing and / or rigid section through the distal end 1021 of the elongated tube 1022 and the proximal end 1032 of the expander end 1030. Alternatively, the lobes of the support element may be connected by a C-shaped base, or the lobes may be independent of each other. In the latter case, the support element may not need to extend beyond the end of the elongated tube 1022, and the blades may simply remain within the recess.
[0057] Figure 11 A longitudinal section of a portion of a vascular dilator 1100 according to an eighth embodiment of the invention is provided. The vascular dilator 1100 includes a dilator shaft 1120 comprising two concentric elongated tubes, wherein an inner tube 1122a is located within an outer tube 1122b. At a distal end 1121 of the dilator shaft 1120, the inner tube 1122a extends more distally than the outer tube 1122b, protruding beyond the distal end of the outer tube 1122b. The depicted embodiment further includes a support element 1150 comprising a tube, such as a hypo tube. Alternatively, the support element 1150 may have a C-shaped cross-section. The support element 1150 is inserted between the two concentric elongated tubes 1122a and 1122b. The support element 1150 extends distally beyond the distal end of the inner tube 1122a by a distance and is located before the distal end of the outer tube 1122b. This configuration provides greater stiffness to the distal end 1121 of the slender tube 1122.
[0058] The proximal end 1132 of the expander end 1130 is configured to partially receive the distal end 1121 of the expander shaft 1120 together with the inner tube 1122a, the support element 1150, and the outer tube 1122b. The proximal end 1132 of the expander end 1130 includes an opening 1133 that provides passage to a cavity 1134. Specifically, the cavity 1134 has a two-step shape to fit snugly around the shape of the distal end 1121 of the expander shaft 1120 formed by the concentric elongated tubes 1122a, 1122b and the support element 1150. Since the support element 1150 spans the distal end 1121 of the concentric elongated tubes 1122a, 1122b and the proximal end 1132 of the expander end 1130, the support element 1150 provides a reinforcing and / or rigid section for the expander end 1130.
Claims
1. A vasodilator, comprising: Slender tube; An expander end is attached to the elongated tube at its distal end. The rigid section of the vascular dilator is formed by the distal end of the elongated tube and the proximal end of the dilator tip. The bending stiffness of the rigid section is higher than the average bending stiffness outside the rigid section of the vascular dilator.
2. The vasodilator according to claim 1, Its features are, The distal end of the slender tube extends 2 mm to 20 mm in the longitudinal direction of the slender tube.
3. The vasodilator according to claim 1, Its features are, The proximal end of the expander tip extends 2 mm to 20 mm in the longitudinal direction of the expander tip.
4. The vasodilator according to claim 1, Its features are, The rigid section extends 4 mm to 40 mm in the longitudinal direction of the vasodilator.
5. The vasodilator according to claim 1, Its features are, The rigid section includes a metal insert.
6. The vasodilator according to claim 1, Its features are, The rigid section includes a braided or wound reinforcement structure.
7. The vasodilator according to claim 1, Its features are, The rigid section includes a polymer insert with relatively high stiffness.
8. The vasodilator according to claim 1, Its features are, The rigid section includes a polymer insert with reinforcing additives.
9. The vasodilator according to claim 1, Its features are, The outer diameter of the rigid section is larger than the diameter of the slender tube.
10. The vasodilator according to any one of the preceding claims, wherein, The expander end is substantially conical and includes an interface, wherein the diameter of the expander increases from the distal end of the elongated tube to the maximum diameter of the expander end, and wherein the expander end tapers gradually from the maximum diameter of the expander end to a circular apex at the distal end of the expander end.
11. The vasodilator according to claim 10, characterized in that, The maximum diameter of the expander end is between 1.1 and 2.5 times the diameter of the slender tube.
12. The vasodilator according to any one of the preceding claims, characterized in that, The vasodilator further includes a vasodilator lumen extending from a proximal end to a distal end of the vasodilator; wherein the diameter of the vasodilator lumen is 0.3 mm to 3.0 mm.
13. The vasodilator according to any one of the preceding claims, characterized in that, The outer diameter of the slender tube is 2.0 mm to 7.0 mm, and / or its length is 100.0 mm to 1100.0 mm.
14. The vasodilator according to any one of the preceding claims, characterized in that, The outer diameter of the expander end is 4.0 mm to 12.0 mm, and / or its length is 15 mm to 200 mm. Preferably, the maximum diameter of the expander end is 1.1 to 2.5 times the outer diameter of the elongated tube.
15. The vasodilator according to any one of the preceding claims, characterized in that, The vascular dilator further includes a dilator hub attached to the elongated tube at its proximal end, preferably for attachment to a guide sheath.
16. The vasodilator according to claim 15, characterized in that, The expander hub is a rigid annular structure having a larger diameter portion and a smaller diameter portion, wherein the smaller diameter portion is configured to fit within the collar of the guide sheath collar.
17. The vasodilator according to claim 15 or claim 16, characterized in that, The expander hub further includes: a retaining member formed on the surface of the smaller diameter portion; and a button slidably inserted into the larger diameter portion and coupled to the larger diameter portion via a biasing element, one end of the biasing element being attached to the button and the other end of the biasing element being attached to the expander hub.
18. A vasodilator assembly comprising a guide sheath and a vasodilator according to any one of the preceding claims, wherein, The length of the guide sheath is arranged such that when the vasodilator is introduced into the guide sheath, the distal end of the guide sheath is aligned with the proximal end of the dilator tip of the vasodilator.
19. The vasodilator assembly according to claim 18, characterized in that, The guide sheath tapers gradually between its proximal end and its distal end.
20. The vasodilator assembly according to claim 18 or claim 19, characterized in that, The guide sheath comprises a double-layered sleeve.
21. The vasodilator assembly according to any one of claims 18 to 20, characterized in that, The guide sheath further includes an annular collar, which preferably includes a fixing accessory configured to receive a fixing member and secure the vasodilator to the fixing member.
22. The vasodilator assembly according to claim 21, characterized in that, After the vascular dilator is inserted into the guide, the fixation member of the dilator engages with the fixation fitting of the guide sheath.
23. A vascular dilator, the vascular dilator comprising a dilator shaft, a dilator end, and a dilator lumen extending through the dilator shaft and the dilator end; in, The expander shaft includes a distal end, the distal end comprising a reinforcing section and a connecting section, the connecting section engaging within a cavity at the expander end, wherein the bending stiffness of the reinforcing section is higher than the average bending stiffness of the remaining portion of the expander shaft distal to the reinforcing section; and The expander end gradually tapers from its maximum diameter near the expander shaft to a smaller diameter at the distal end of the expander end.