CN112807059A

CN112807059A - Self-expandable medical implant and medical device

Info

Publication number: CN112807059A
Application number: CN202110220853.6A
Authority: CN
Inventors: 张瑶俊; 王雪琴; 刘伟; 朱京; 李俊菲
Original assignee: Shanghai Microport Medical Group Co Ltd
Current assignee: Shanghai Microport Medical Group Co Ltd
Priority date: 2021-02-26
Filing date: 2021-02-26
Publication date: 2021-05-18

Abstract

The invention provides a self-expandable medical implant and a medical device. When the medical implant is implanted into a target position in a patient body, the support body can be expanded according to actual conditions so as to completely cover the area needing to be sealed.

Description

Self-expandable medical implant and medical device

Technical Field

The invention relates to the technical field of medical instruments, in particular to a self-expandable medical implant and a medical device.

Background

Atherosclerosis is a chronic inflammatory disease in which patients develop disease from late years, clinical symptoms usually appear in adults, and the disease course of atherosclerosis progresses slowly, up to decades. Plaque forms in the intima of atherosclerotic arterial vessels and can cause narrowing of the vessel lumen or thrombosis. Although the exact initiating factor for plaque formation is still unknown, it is widely believed that endothelial damage is its initiating factor, which may be triggered by smoking, hypertension, or immune damage, among other factors. The permeability of damaged endothelial cells is enhanced, and endothelial macrophages engulf a large number of circulating low-density lipoproteins (LDL), leading to further damage of endothelial cells through modification, and then more macrophages are recruited to become lipid-rich foam cells deposited on the inner membrane of blood vessels. Meanwhile, in order to repair the vascular endothelial function, smooth muscle cells migrate from the tunica media to the intima to proliferate and produce connective tissue matrix and form a fibrous cap covering the lipid core, resulting in further thickening of the lesion to form plaques. Plaques progressively enlarge as the lesion progresses and are divided into stable and unstable plaques.

Unstable plaques are formed by a thin and unstable fibrous cap covering a large lipid core, easily rupture and cause thrombosis, which in turn causes acute arterial symptoms. The fibrous cap of the stable plaque is thick and not prone to rupture.

Studies have found that atherothrombosis formation and thromboembolic complications are more associated with plaque stability than plaque size. For example, stable angina is associated with smooth fibrous coronary plaque (a stable plaque), while unstable angina, Acute Myocardial Infarction (AMI), and sudden cardiac death are all nearly associated with unstable plaques. As another example, in patients with atherosclerotic carotid disease, patients with irregular or ulcerative plaques (i.e., unstable plaques) exhibit a higher risk of ischemic stroke regardless of the degree of luminal stenosis.

In addition to self-rupture, plaque rupture can also occur when stents are implanted or balloon angioplasty are performed in atherosclerotic blood vessels to dilate stenotic vessels, and can also cause tearing of the vessel, which can lead to the formation of unstable plaque within the vessel.

Disclosure of Invention

The invention aims to provide a self-expandable medical implant and a medical device, wherein the self-expandable medical implant can be implanted into a blood vessel to convert unstable plaques on the intima of the blood vessel into stable plaques or close the tearing part of the blood vessel to avoid forming the unstable plaques.

To achieve the above objects, the present invention provides a self-expandable medical implant comprising a support body and at least one closed loop; the support body is a three-dimensional helical structure in an expanded state, and the closed loop is connected to at least one end of the three-dimensional helical structure; the self-expandable medical implant is used for implanting into a target cavity and providing radial supporting force for the inner wall of the target cavity.

Optionally, the support has a radial crush resistance of [10KPa, 100KPa ].

Optionally, the support has a radial crush resistance of [30KPa, 50KPa ].

Optionally, the radial supporting force of the closed ring is greater than or equal to the radial supporting force of the supporting body; and/or the presence of a gas in the gas,

the self-expandable medical implant further comprises a fixing ring which is arranged in the middle of the support body, and the radial supporting force of the fixing ring is larger than or equal to that of the support body and the radial supporting force of the closed ring.

Optionally, at least one of said closed rings has a radial crush resistance of [10KPa, 100KPa ]; and/or the presence of a gas in the gas,

the radial anti-extrusion performance of the fixing ring is [10KPa, 100KPa ].

Optionally, at least one of said closed rings has a radial crush resistance of [30KPa, 50KPa ]; and/or the presence of a gas in the gas,

the radial anti-extrusion performance of the fixing ring is [30KPa, 50KPa ].

Optionally, at least a portion of the outer sidewall of the self-expandable medical implant is formed with a relief structure.

Optionally, the pitch of the three-dimensional helical structure is uniform or non-uniform over the entire length in the axial direction of the support body.

Optionally, on the circumferential surface of the support body, the percentage of the area covered by the three-dimensional helical line structure to the area of the circumferential surface of the support body is (0,100%).

Optionally, on the circumferential surface of the support body, the percentage of the area covered by the three-dimensional helical line structure to the area of the circumferential surface of the support body is [ 10%, 60% ].

Optionally, the three-dimensional helical line structure comprises a plurality of sequentially connected helical turns, and the widths of the helical turns are equal or unequal.

Optionally, the self-expandable medical implant is loaded with a drug.

To achieve the above object, the present invention also provides a medical device comprising a delivery mechanism and a self-expandable medical implant as described in any of the preceding items; the delivery mechanism is used for delivering the self-expandable medical implant to a preset position in a target cavity.

Optionally, the delivery mechanism comprises an outer sheath and an inner sheath; the outer sheath having an inner lumen extending axially therethrough; the inner sheath is movably arranged in the inner cavity of the outer sheath; the self-expandable medical implant is compressed within the inner lumen of the outer sheath and is located at the distal end of the inner sheath.

Optionally, the inner lumen of the outer sheath comprises a first section and a second section, the second section being attached to a distal end of the first section, and the second section having an inner diameter greater than an inner diameter of the first section; the second section is for receiving the self-expanding medical implant.

Optionally, the inner sheath includes a rod portion and a pushing portion, the pushing portion is disposed at a distal end of the rod portion, and an outer diameter of the pushing portion is larger than an outer diameter of the rod portion; the pusher is movably disposed within the second section and is adapted to contact a proximal end of the self-expanding medical implant.

Compared with the prior art, the self-expandable medical implant and the medical device have the following advantages:

first, the aforementioned self-expandable medical implant comprises a supporting body which is a three-dimensional helical structure in an expanded state, and at least one closed loop which is connected to at least one end of the three-dimensional helical structure. When the self-expandable medical implant is implanted into a preset position of a target cavity, such as a position where an unstable plaque is formed in a blood vessel, the support body can be expanded according to the shape of the unstable plaque so as to sufficiently cover the unstable plaque and trigger foreign body reaction, and endothelialization is stimulated to convert the unstable plaque into the stable plaque so as to prevent thrombus caused by plaque rupture. Alternatively, the self-expandable medical implant can be implanted in a position where a tear occurs in a blood vessel, and the support body can completely cover the tear of the blood vessel after expansion, so that endothelialization is stimulated to promote repair of the tear. The closed ring can prevent the end part of the support body from being not attached to the inner wall of the blood vessel to cause thrombus.

Secondly, the radial anti-extrusion performance of the self-expandable medical implant is [10KPa, 100KPa ], and more preferably [30KPa, 50KPa ], so that the self-expandable medical implant can provide radial supporting force matched with the radial anti-extrusion performance of the inner wall of the target cavity, so that the self-expandable medical implant can be effectively positioned at the preset position of the target cavity, and unstable plaque rupture caused by damage to the unstable plaque can be avoided.

Drawings

The drawings are included to provide a better understanding of the invention and are not to be construed as unduly limiting the invention. Wherein:

FIG. 1 is a schematic view of a self-expanding medical implant according to one embodiment of the present invention;

FIG. 2 is a schematic diagram of a medical device provided in accordance with an embodiment of the present invention;

FIG. 3 is a schematic view of a self-expanding medical implant according to one embodiment of the present invention implanted in a predetermined location in a target lumen to cover unstable plaque;

FIG. 4 is a schematic view of the self-expanding medical implant of FIG. 1 showing a friction-enhancing pattern formed on the outer sidewall of the support body;

FIG. 5 is a B-B cross-sectional view of the self-expanding medical implant of FIG. 1, showing the support body having a rectangular cross-section;

FIG. 6 is a schematic structural view of a self-expanding medical implant according to a second embodiment of the present invention;

FIG. 7 is a schematic view of a medical device according to a second embodiment of the present invention, showing the closed loop;

FIG. 8 is a schematic view of a medical device according to a second embodiment of the present invention showing a closed loop;

FIG. 9 is a schematic structural view of a self-expanding medical implant provided in accordance with a third embodiment of the present invention;

FIG. 10 is a schematic view of a self-expanding medical implant according to a third embodiment of the present invention compressed into a cylindrical configuration, with the closed loop not shown;

FIG. 11 is a schematic view of a self-expanding medical implant according to a third embodiment of the present invention compressed into a cylindrical shape, with the view directions of FIG. 11 and FIG. 10 being different;

FIG. 12 is a schematic view of a self-expanding medical implant according to a third embodiment of the present invention compressed into a planar configuration, with the closed loop not shown;

FIG. 13 is a simplified schematic illustration of a self-expanding medical implant compressed into a planar configuration, without the spring coil and closed loop contours shown, in accordance with a third embodiment of the present invention;

fig. 14 is a schematic structural diagram of a medical device according to a third embodiment of the present invention.

[ reference numerals are described below ]:

100-self-expandable medical implant;

110-support, 111-relief structure, 120-closed ring;

200-a conveying mechanism;

210-an outer sheath, 211-a first section, 212-a second section;

220-inner sheath, 221-shaft, 222-pushing.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.

Furthermore, each of the embodiments described below has one or more technical features, which, however, does not mean that all of the technical features of any one embodiment must be implemented simultaneously by the inventor or that only some or all of the technical features of different embodiments can be implemented separately. In other words, those skilled in the art can selectively implement some or all of the features of any embodiment or combinations of some or all of the features of multiple embodiments according to the disclosure of the present invention and according to design specifications or implementation requirements, thereby increasing the flexibility in implementing the invention.

As used in this specification, the singular forms "a", "an" and "the" include plural referents, and the plural forms "a plurality" includes more than two referents unless the content clearly dictates otherwise. As used in this specification, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise, and the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either fixedly connected, detachably connected, or integrally connected. Either mechanically or electrically. Either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The core idea of the invention is to provide a self-expandable medical implant, which comprises a supporting body and a closed ring, wherein the supporting body is of a three-dimensional spiral line structure in an expanded state, and the closed ring is arranged at the end part of the supporting body. The self-expandable medical implant can be used for implanting a target lumen, such as a blood vessel, in which atheroma is formed to form an unstable plaque, and can be expanded according to the shape of the unstable plaque, so that the self-expandable medical implant adapts to the cross section of the blood vessel to sufficiently close the unstable plaque and stimulates endothelialization of the blood vessel to convert the unstable plaque into a stable plaque. Alternatively, when a tear occurs in the inner wall of the blood vessel, the self-expanding medical implant may be expanded at the tear and stimulate endothelialization to seal the tear. That is, the present invention provides a self-expanding medical implant that is adapted to seal unstable plaque of atherosclerosis or other vascular tears. For convenience of description, the self-expandable medical implant is implanted into a blood vessel and positioned at a position where an unstable plaque is formed in the blood vessel, and the unstable plaque is converted into a stable plaque as an example. The following description can be modified by those skilled in the art to adapt it to the situation when the self-expandable medical implant is used to seal a vascular tear. In addition, it should be noted that the term "self-expandable medical implant" as used herein means a medical implant made of a material having good resilience and being held in a compressed state when subjected to radial pressure, and the medical implant expands under its own resilience when the radial pressure is removed. Typically, the self-expanding medical implant is made of a shape memory alloy. The three-dimensional helical line structure is a three-dimensional curve structure formed by winding a linear structure around an axis by turns starting from a fixed point. As such, a "helical turn" as referred to hereinafter is a non-closed ring that surrounds 360 degrees circumferentially.

To further clarify the objects, advantages and features of the present invention, a more particular description of the invention will be rendered by reference to the appended drawings. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention. The same or similar reference numbers in the drawings identify the same or similar elements.

FIG. 1 illustrates a schematic structural view of a self-expanding medical implant 100 provided in accordance with an embodiment of the present invention; FIG. 6 is a schematic structural view of a self-expanding medical implant 100 provided in accordance with a second embodiment of the present invention; fig. 9 is a schematic structural view of a self-expandable medical implant according to a third embodiment of the present invention.

Referring to fig. 1, 6 and 9, the self-expandable medical implant 100 includes a supporting body 110 and at least one closed loop 120, wherein the supporting body 110 has a three-dimensional spiral structure in a natural expansion state, and the closed loop 120 is connected to at least one end of the three-dimensional spiral structure. The self-expanding medical implant 100 is configured to be implanted at a predetermined location within a target lumen and provide radial support to an inner wall of the target lumen to retain the self-expanding medical implant 100 at the predetermined location. In one non-limiting embodiment, the target lumen is, for example, a blood vessel, and the predetermined location is a region of the blood vessel in which an unstable plaque is formed. In actual use, as shown in fig. 2, the self-expanding medical implant 100 is compressed to a compressed state and loaded into a delivery mechanism 200, and the delivery mechanism 200 delivers the self-expanding medical implant 100 to the desired location for release. The expanded form of the supporting body 110 of the self-expandable medical implant 100 is a three-dimensional helical structure including a plurality of open helical turns, so that the diameter of each helical turn of the supporting body 110 after expansion is adapted to the thickness of the unstable plaque (as shown in fig. 3). That is, the support body 110 may be expanded according to the shape of the unstable plaque to ensure complete coverage of the unstable plaque, so that the blood vessel may effectively close the unstable plaque to convert the unstable plaque into the stable plaque when endothelialized by the foreign body stimulation of the support body 110. Moreover, the support body 110 in a compressed state has a small radial dimension, which facilitates passage through tortuous, stenotic vessels, and may be used to treat small vessel lesions. It should be appreciated that the radial dimension of the support body 110 in the compressed state is smaller than the radial dimension of the support body 110 in the expanded state.

The support body 110 is used for being attached to the inner wall of the blood vessel and providing radial support force to the inner wall of the blood vessel. Referring to fig. 4, at least a portion of the outer sidewall of the supporting body 110 is formed with a concave-convex structure 111 to form a friction-increasing pattern, and the outer sidewall refers to the sidewall of the supporting body 110 contacting with the inner wall of the blood vessel (including the unstable plaque). The friction increasing pattern is used to increase the friction between the support body 110 and the inner wall of the blood vessel, and reduce the possibility of displacement of the support body 110 due to blood flow impact.

In the embodiment of the present invention, the three-dimensional helical line structure has a uniform or non-uniform pitch L over the entire length in the axial direction of the support body 110, that is, the distance between any two adjacent helical turns of the three-dimensional helical line structure is equal or unequal. For example, in a specific implementation, the pitch L of the three-dimensional helical line structure may decrease and then increase along the axial direction of the supporting body 110, that is, the pitch L of the three-dimensional helical line structure decreases from the two ends of the supporting body 110 to the middle.

Optionally, on the circumferential surface of the support body 110, the percentage of the area covered by the three-dimensional helical line structure to the circumferential surface of the support body 110 is 0 to 100%, and preferably 10 to 60%. The "circumferential surface of the support 110" refers to a virtual curved surface that surrounds the axis of the support 110 and passes through the three-dimensional spiral structure. Taking the axis of the supporting body 110 in the natural expansion state as a straight line and the diameters of the spiral turns are all equal as an example, the space occupied by the supporting body 110 can be regarded as a cylinder, and the circumferential surface of the supporting body 110 is the circumferential surface of the cylinder.

The cross section shape of any position of any spiral coil of the three-dimensional spiral line structure is not limited in the embodiment of the invention, and the cross section shape can be circular, oval, square, rectangular (as shown in fig. 5), trapezoid and the like. The cross sections of any different positions of the three-dimensional spiral line structure can be the same or different in shape, and the diameters of the cross sections can be the same or different. It is to be understood that if the cross-section is non-circular, the diameter refers to the diameter of the circle circumscribing the cross-section. The cross-section may have a diameter of less than 500um, and when the cross-sections have different diameters, it is preferable that the cross-section having the largest diameter is located at a middle position of the three-dimensional helical structure (i.e., the cross-section having the largest diameter is located at an equal or substantially equal distance from both ends of the three-dimensional helical structure). It should be noted that regardless of the cross-section of the coil, the coil should have a smooth outer surface to facilitate vascular endothelialization.

In addition, the thickness (not labeled in the figures) of any spiral turn of the three-dimensional helical structure can be less than or equal to 100um, preferably less than or equal to 50um, and more preferably less than or equal to 30 um. The thickness here means the dimension of the coil in the radial direction. In particular, when the cross section of the coil at any position is trapezoidal, the width of the inner wall of the coil (not labeled in the figure) is preferably smaller than the width D of the outer wall of the coil, that is, the smaller length base of the trapezoid is disposed toward the axis of the support body 110, and the larger length base is disposed toward the outer side of the support body 110. The width is a distance between two opposite sides with a smaller distance on the projection of the spiral coil when the spiral coil is projected on a plane parallel to the axis of the support 110, and can be referred to the reference of fig. 1.

Further, the self-expandable medical implant 100 includes two closed loops 120 (refer to fig. 6 and 9), the two closed loops 120 are respectively connected to two ends of the supporting body 110, and an outer wall of the closed loop 120 is configured to be attached to an inner wall of a blood vessel. This is provided to avoid the end of the support body 110 being in a free state in the blood vessel and being separated from the blood vessel wall (i.e., the end of the three-dimensional spiral line does not contact the blood vessel wall) and causing thrombus. The "both end portions of the support body 110" as described herein means both end portions of the three-dimensional helical line structure constituting the support body 110.

The forming manner of the closed loop 120 is not limited in the embodiment of the present invention. For example, the closed loop 120 may be a one-piece structure with the supporting body 110, and specifically, the end surfaces of two ends of a three-dimensional spiral line may be connected with the side surfaces of the corresponding outermost spiral coils to form the closed loop 120, and the remaining portion still having the three-dimensional spiral line structure constitutes the supporting body 110. Or, the closed ring 120 and the supporting body 110 are formed separately and then connected into a whole.

To maintain the self-expanding medical implant 100 at the unstable plaque, the radial support provided by the self-expanding medical implant 100 to the inner wall of the blood vessel should be able to resist blood flow impingement. It should be understood that the radial supporting force provided by the self-expandable medical implant 100 to the inner wall of the blood vessel corresponds to the radial anti-extrusion performance of the self-expandable medical implant 100 itself, i.e., the radial supporting force applied by the self-expandable medical implant 100 to the inner wall of the blood vessel can be characterized by the radial anti-extrusion performance of the self-expandable medical implant 100. Optionally, the radial crush resistance of the self-expanding medical implant 100 is [10KPa, 100KPa ], preferably [30KPa, 50KPa ]. It should be understood that the specific value of the radial supporting force provided by the supporting body 110 is determined according to actual needs, and the radial supporting force should be as small as possible under the premise of ensuring that the self-expandable medical implant 100 can resist the impact of blood flow, so as to reduce the adverse effect on the unstable plaque and avoid the rupture of the unstable plaque.

The crush resistance of the self-expanding medical implant 100 may be tested by the test method described in YY/T0663.2-2016. Specifically, first, the self-expandable medical implant 100 is fixed to a test fixture; then, compressing the self-expanding medical implant 100 with a consistent compression rate, the initial diameter of the self-expanding medical implant 100 should be equal to the maximum diameter of the blood vessel; the load and corresponding diameter are recorded during compression until the force is significantly reduced or the diameter is reduced by at least 50%. This test is repeated for each of the self-expanding medical implant 100 configurations for which a vessel minimum diameter is specified.

Optionally, in some embodiments, the radial support force provided by the support body 110 to the inner wall of the blood vessel is sufficient to hold the self-expandable medical implant 100 at the unstable plaque, i.e. the radial crush resistance of the support body 110 is [10KPa, 100KPa ], preferably [30KPa, 50KPa ]. Alternatively, in other embodiments, at least one of the closed loops 120 provides sufficient radial support to the inner wall of the vessel to hold the self-expanding medical implant at the unstable plaque, i.e., at least one of the closed loops 120 has a radial crush resistance of [10KPa, 100KPa ], preferably [30KPa, 50KPa ]. In this way, the radial supporting force provided by the supporting body 110 may be smaller than the radial supporting force provided by at least one of the closed rings 120, so as to further avoid damaging unstable plaque, and at this time, it is preferable that the closed rings 120 and the supporting body 110 are formed separately and then connected into a whole. In still other embodiments, the self-expanding medical implant 100 may further comprise a fixation ring (not shown) disposed in a central portion of the support body, the fixation ring being operable to provide radial support for holding the self-expanding medical implant 100 at unstable plaque, i.e., the fixation ring provides a radial crush resistance of [10KPa, 100KPa ], preferably [30KPa, 50KPa ], such that the radial support provided by the support body 110 and the closure ring 120 may be reduced. In addition, friction increasing patterns can be arranged on the outer side walls of the closed ring 120 and the fixing ring so as to enhance the friction force between the closed ring 120 and the fixing ring and the inner wall of the blood vessel.

The self-expandable medical implant 100 of this embodiment may be made of a metal material such as nitinol or other metal materials, or a polymer material such as polyester, as long as it has high elasticity and ensures self-expandable properties. Preferably, at least a portion of the structure of the self-expanding medical implant 100 may be made of a degradable material. Degradable materials that may be used include, but are not limited to, iron alloys, zinc alloys, magnesium alloys, polylactic acid based compounds, Polycaprolactone (PCL), and the like. The degradation time of the self-expanding medical implant 100 is not expected to be too long, for example less than or equal to one year, preferably 6 months or less, more preferably 3 months or less.

Further, the self-expandable medical implant 100 is loaded with a drug, which may be a pure drug or a composition of a pure drug and a drug carrier. Such pure drugs include, but are not limited to, fibroblast growth factor promoting, endothelial growth factor promoting, and cell repair antibodies such as CD 34. The drug carrier is, for example, a slow release material including, but not limited to, PDLLA (racemic polylactic acid), hyaluronic acid, and the like. The drug-loaded self-expanding medical implant 100 may promote vascular endothelialization, reducing the time for the unstable plaque to transform into a stable plaque. The release period of the drug may be less than or equal to 3 months, preferably less than or equal to 1 month.

The embodiment of the present invention does not limit the form of the self-expandable medical implant 100 for loading the drug. For example, after the support body 110 and the closed ring 120 are molded, the surface of the support body 110 and the closed ring 120 is coated with the drug. For another example, a groove or a through hole is formed in the support body 110 and the closed ring 120, and the groove or the through hole is filled with the drug. For another example, the self-expandable medical implant 100 is made of a polymer material, and before the self-expandable medical implant 100 is molded, the polymer material used for making the self-expandable medical implant 100 is mixed with the drug, and then the mixture is processed into the self-expandable medical implant 100 by any suitable method.

Further, referring to fig. 3, the embodiment of the present invention further provides a medical apparatus, which includes a delivery mechanism 200 and the self-expandable medical implant 100 as described above, wherein the delivery mechanism 200 is used to deliver the self-expandable medical implant 100 to a predetermined position in the target lumen.

Optionally, the delivery mechanism 200 includes an outer sheath 210 and an inner sheath 220. The outer sheath 210 has an inner lumen extending axially therethrough. The inner sheath 220 is movably disposed within the inner lumen of the outer sheath 210. The self-expanding medical implant 100 is compressed within the inner lumen of the outer sheath 210 and is positioned distal to the inner sheath 220.

In more detail, the inner lumen of the outer sheath 210 comprises a first section 211 and a second section 212, the second section 212 being attached to a distal end of the first section 211. The second section 212 has an inner diameter greater than the inner diameter of the first section 211, and the second section 212 is configured to receive the self-expanding medical implant 100. The inner sheath 220 includes a shaft portion 221 and a pushing portion 222, and the pushing portion 222 is connected to a distal end of the shaft portion 221. The pushing portion 222 has an outer diameter greater than the shaft portion 221, and the pushing portion 222 is movably disposed in the second section 212 and is configured to contact the proximal end of the self-expandable medical implant 100.

The self-expanding medical implant 100 and the medical device are described next herein with reference to specific embodiments. It should be understood that the following examples are given by way of illustration only, and are not intended to limit the invention in any way, given the construction, size and manner of formation of the self-expanding medical implant 100 and the medical device.

< example one >

Fig. 1 shows a schematic structural view of a self-expandable medical implant 100 provided in this embodiment. In this embodiment, the self-expandable medical implant 100 is made of nitinol with a wall thickness of 20 um.

The nitinol tube is laser cut and formed into a three-dimensional helical line structure, then the end parts of the two end parts of the three-dimensional helical line structure are respectively welded with the side wall of the outermost helical coil to form the closed ring (not shown in fig. 1), and the rest part still in the three-dimensional helical line structure forms the support body 110.

The surface of the self-expandable medical implant 100 is cut by laser to form grooves, and the surface of the self-expandable medical implant 100 is coated with a drug by spraying, wherein the drug consists of CD34 and a carrier PDLLA, and the release period is 2 months.

The friction-increasing pattern 111 (fig. 4) etched on the outermost two spiral turns of the support body 110 to form a concavo-convex structure is shown.

In this embodiment, the thickness of the spiral coil of the supporting body 110 is 20 um. The support body 110 may include ten coils, and the width D of two coils at the outermost side of the support body 110 is 300um, the width D of the middle coil is 50um, and the pitch L of the support body 110 is 50 um.

In assembling the medical device, the closed loop is collapsed into a doubled-over, linear configuration, the support 110 is stretched into a straight line, and the self-expanding medical implant 100 is loaded entirely within the delivery mechanism 200, as shown in fig. 3.

< example two >

Fig. 6 is a schematic structural view of a self-expandable medical implant 100 provided in this embodiment. In this embodiment, the support body 110 of the self-expandable medical implant 100 is formed by laser cutting a polymer tube with a wall thickness of 30um and an outer diameter of 4mm, and the polymer tube is made of a blend of PLGA (polylactic acid-co-hydroxy lactic acid) and PCL.

The polymer pipe is laser cut and formed into a three-dimensional helical line structure to form the support 110. The support body 110 may have ten coils, each coil having a thickness of 30um and an outer diameter of 4mm (when normally expanded). The width D of the coil gradually increases from both ends of the support body 110 to the middle, and specifically, the width of the coil at the outermost side is 100um, and the width of the coil at the middle most is 500 um. The pitch of supporter 110 reduces from both ends to centre gradually to the example of the position shown in fig. 6, and the pitch of the first helicoid circle in right side to the second helicoid circle in right side is 50um, and the pitch between two middle helicoids is 20um, and the pitch of the first helicoid circle in left side to the second helicoid circle in left side is 50 um.

The ends of the support body 110 are wrapped around and thermally fixed to a nitinol ring that forms the closed loop 120, and the radial support provided by the closed loop 120 is greater than the radial support provided by the support body 110.

The surface of the self-expandable medical implant 100 is laser cut to form grooves and loaded with a drug, CD34, by spraying, and its release cycle is one month.

When assembling the medical device, the closure ring 120 is first collapsed into a doubled-over, linear configuration and folded inwardly to reduce the length of the self-expanding medical implant 100 in a compressed state. Then, the support body 110 is stretched, the spiral coil of the support body 110 is stretched to a diameter of 1mm, and the support body is shaped at a low temperature. Finally, the self-expandable medical implant 100 is loaded into the delivery mechanism 200 (as shown in fig. 7 and 8).

< example three >

Fig. 9 shows a schematic structural view of a self-expandable medical implant 100 provided in the present embodiment. The support body 110 of the self-expandable medical implant 100 in this embodiment is formed by braiding PLLA (polylactic acid) wire. The cross section of the PLLA wire is circular and the diameter is 20 um. The closure ring 120 is injection molded from PLLA.

PLLA filaments are braided into a three-dimensional helical linear structure to construct the support body 110. The support body 110 may have ten coils, the width of the coil being 20um, and the pitch L being 20 um.

The end of the support body 110 is integrally connected to the closed loop 120 by weaving.

The surface of the self-expandable medical implant 100 is subjected to erosion treatment to form a groove, and the groove is filled with a medicament, wherein the medicament is CD34, and the medicament release period is one month.

Upon assembly of the medical device, the self-expanding medical implant 100 is first compressed axially to form the self-expanding medical implant 100 into a cylindrical configuration (as shown in fig. 10 and 11). A force is then applied to the self-expanding medical implant 100 perpendicular to its axis to compress the self-expanding medical implant 100 into a planar rectangular configuration (as shown in fig. 12 and 13). The self-expanding medical implant 100 is then stretched at two opposing vertices of a planar rectangle to form it into a parallelogram structure. Finally, the self-expandable medical implant 100 in a parallelogram configuration is loaded into the delivery mechanism 200 (as shown in fig. 14).

Although the present invention is disclosed above, it is not limited thereto. Various modifications and alterations of this invention may be made by those skilled in the art without departing from the spirit and scope of this invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A self-expanding medical implant comprising a support and at least one closed loop; the support body is a three-dimensional helical structure in an expanded state, and the closed loop is connected to at least one end of the three-dimensional helical structure; the self-expandable medical implant is used for implanting into a target cavity and providing radial supporting force for the inner wall of the target cavity.

2. The self-expanding medical implant of claim 1, wherein the radial crush resistance of the support body is [10KPa, 100KPa ].

3. The self-expanding medical implant of claim 1, wherein the radial crush resistance of the support body is [30KPa, 50KPa ].

4. A self-expanding medical implant according to claim 1, wherein the radial support force of the closed loop is greater than or equal to the radial support force of the support body; and/or the presence of a gas in the gas,

5. The self-expanding medical implant of claim 4, wherein at least one of said closed loops has a radial crush resistance of [10KPa, 100KPa ]; and/or the presence of a gas in the gas,

the radial anti-extrusion performance of the fixing ring is [10KPa, 100KPa ].

6. A self-expanding medical implant according to claim 5, wherein at least one of said closed loop crush resistances is [30KPa, 50KPa ]; and/or the presence of a gas in the gas,

the radial anti-extrusion performance of the fixing ring is [30KPa, 50KPa ].

7. The self-expanding medical implant according to any one of claims 1, 4-6, wherein at least a portion of an exterior sidewall of the self-expanding medical implant is formed with a relief structure.

8. A self-expanding medical implant according to claim 1, wherein the pitch of said three-dimensional helical structure is uniform or non-uniform over the entire length in the axial direction of said supporting body.

9. A self-expanding medical implant according to claim 1, wherein the percentage of the area covered by the three-dimensional helix structure to the area of the circumferential surface of the support body is (0,100% ], on the circumferential surface of the support body.

10. A self-expanding medical implant according to claim 9, wherein the percentage of the area covered by the three-dimensional helix structure to the area of the circumferential surface of the support body is [ 10%, 60% ], on the circumferential surface of the support body.

11. A self-expanding medical implant according to claim 1, wherein said three-dimensional helical structure comprises a plurality of sequentially connected helical turns, said helical turns being of equal or unequal width.

12. The self-expanding medical implant of claim 1, wherein the self-expanding medical implant is loaded with a drug.

13. A medical device comprising a delivery mechanism and a self-expanding medical implant as claimed in any one of claims 1 to 12; the delivery mechanism is used for delivering the self-expandable medical implant to a preset position in a target cavity.

14. The medical device of claim 13, wherein said delivery mechanism comprises an outer sheath and an inner sheath; the outer sheath having an inner lumen extending axially therethrough; the inner sheath is movably arranged in the inner cavity of the outer sheath; the self-expandable medical implant is compressed within the inner lumen of the outer sheath and is located at the distal end of the inner sheath.

15. The medical device of claim 14, wherein the inner lumen of the outer sheath comprises a first section and a second section, the second section being attached to a distal end of the first section, and an inner diameter of the second section being greater than an inner diameter of the first section; the second section is for receiving the self-expanding medical implant.

16. The medical device of claim 15, wherein the inner sheath comprises a shaft portion and a pusher portion, the pusher portion being disposed at a distal end of the shaft portion and having an outer diameter greater than an outer diameter of the shaft portion; the pusher is movably disposed within the second section and is adapted to contact a proximal end of the self-expanding medical implant.