A "lantern-shaped" transcatheter mitral valve stent with variable diameter

Abstract

The present application discloses a "lantern-shaped" variable-diameter transcatheter artificial mitral valve stent, which belongs to the field of medical device technology. It includes a valve inner frame, a valve outer frame sleeved on the outside of the valve inner frame, and a connecting film connecting the valve outer frame and the valve inner frame. The valve outer frame includes a lantern-shaped outer stent body and an outer frame coating. The outer frame coating is arranged near the aorta side semi-open window. The grid lantern-shaped stent body includes an atrial side umbrella disc, a ventricular side variable diameter structure, and a negative pressure suction cup connected to the atrial side umbrella disc and the ventricular side variable diameter structure and used to strengthen anchoring; the valve inner frame includes a grid cylindrical inner stent body and an inner frame coating. The inner side of the inner stent body is connected to an artificial valve leaflet. The lantern-shaped design of the outer stent and the valve ring suction cup for auxiliary anchoring solve the problem of difficult anchoring of the artificial mitral valve during transcatheter replacement. The design of the dynamically changeable valve outer frame without coating on one side alleviates the problem of easy obstruction of the left ventricular outflow tract after implantation of the coated stent.

Description

Technical Field

[0001] The present application relates to the field of medical device technology, and in particular to a "lantern-shaped" variable-diameter transcatheter artificial mitral valve stent. Background Art

[0002] Mitral regurgitation (MR) is the most common type of heart valve disease, and its occurrence is associated with a variety of heart diseases and degenerative changes. Epidemiological studies in Western countries have shown that MR is the most common valvular disease in the elderly population aged 65 and above. For elderly patients with multiple systemic diseases, surgical risks are high and survival benefits are limited. Transcatheter mitral valve replacement (TMVR) provides a new treatment option for high-risk MR patients who cannot undergo surgery. However, due to the more complex anatomical structure of the mitral valve, high ventricular pressure and relative movement of the mitral valve annulus, the design of TMVR products is extremely challenging.

[0003] The geometric shape of the mitral valve annulus is saddle-shaped, not circular or D-shaped, and its structure does not lie on a single plane. This complex geometric feature may result in incomplete matching between the valve and the annulus during artificial valve replacement surgery, thereby increasing the risk of paravalvular leakage after surgery. The annulus is soft, and the high ventricular pressure during ventricular contraction makes it impossible for the artificial valve to provide sufficient friction, resulting in anchoring difficulties and easy displacement. In addition, it has been recognized in surgical mitral valve intervention that postoperative left ventricular outflow tract obstruction (LVOTO) is an important complication associated with increased mortality. Studies have shown that LVOTO is closely related to the structural design of the stent.

[0004] To address the above issues, multiple TMVR valve products are under development worldwide. Various structures have been proposed, such as apical cable fixation, where the cable is tied to the stent and then penetrates the myocardium to be fixed on the outer surface of the apex. However, this method has not been widely accepted due to damage to the myocardial tissue. Radial interference and barb-penetrating valve fixation methods, although they can provide better anchoring performance, excessive radial extent may obstruct the left ventricular outflow tract, and barbs piercing the valve leaflets may cause secondary damage due to frequent traction from the heartbeat. Although native valve capture and annular valve anchoring methods do not harm heart tissue, experiments have been hindered by the chordae tendineae structure under the native valve, and the implantation success rate of this anchoring method is low. In summary, the anti-migration design of artificial mitral valve stents is still imperfect. Relying on increasing the diameter to resist displacement will compress the left ventricular outflow tract, and the addition of auxiliary anchoring devices has the problem of damaging heart tissue and making implantation difficult.

[0005] Therefore, there is an urgent need to propose a new type of artificial mitral valve that is easy to implant, which requires a valve frame that can avoid left ventricular outflow tract obstruction caused by excessive diameter without damaging heart tissue and can provide sufficient anti-displacement ability. Summary of the Invention

[0006] The purpose of this application is to provide a "lantern-shaped" variable-diameter transcatheter artificial mitral valve stent.

[0007] To achieve the above-mentioned purpose, the present application provides a "lantern-shaped" variable-diameter transcatheter artificial mitral valve stent, including a valve inner frame, a valve outer frame that changes dynamically and is sleeved on the outside of the valve inner frame, and a connecting film connecting the valve outer frame and the valve inner frame. The valve outer frame includes a lantern-shaped outer stent body and an outer frame covering arranged on the inner side of the outer stent body. The outer frame covering is arranged near the semi-open window on the aorta side. The grid lantern-shaped stent body includes an atrial side umbrella disc, a ventricular side variable-diameter structure, and a negative pressure suction cup connecting the atrial side umbrella disc and the ventricular side variable-diameter structure and used to strengthen anchoring; the valve inner frame includes a grid cylindrical inner stent body and an inner frame covering arranged on the inner side of the inner stent body. The inner side of the inner stent body is connected to an artificial valve leaflet.

[0008] Preferably, the atrial side umbrella disc is formed by a circumferential array of 16 "petal-shaped" rhombus-like unit structures, which are connected in the middle by connecting ribs, and the edges of the rhombus-like unit structures are smooth curves.

[0009] Preferably, the diamond-like unit structure is higher on the side close to the aorta than on the side away from the aorta.

[0010] Preferably, the diameter of the middle section of the ventricular side variable diameter structure is larger than the diameters on both sides, presenting a lantern structure that is narrow at both ends and wide in the middle. It is woven from 32 nickel-titanium alloy wires with a weaving angle of 65°; the upper end cross-sectional diameter is 30 mm, the abdominal cross-sectional diameter is 38 mm, the bottom end cross-sectional diameter is 27 mm, and the height is 11 mm.

[0011] Preferably, there are 16 fixing rings at the end of the ventricular side reducing structure, and 16 fixing rings are provided at the end of the valve inner frame. The fixing rings of the ventricular side reducing structure are bound and assembled with the fixing rings on the valve inner frame and then fixed to the delivery system.

[0012] Preferably, the negative pressure suction cup cooperates with the 16 unit structures of the valve outer frame, totaling 16 groups of negative pressure suction cup structures, with 17 suction cup units in each group, distributed in an "X" shape that is wide at the top and narrow at the bottom on the surface of the valve outer frame.

[0013] Preferably, the inner support body is a grid columnar structure, the diameters of the cross sections of the inner support body are consistent, the unit grid is rhombus-like, with 16 repeating units in a single row, and 3 rows in total, connected in the middle by a rectangular connecting rod.

[0014] Preferably, the artificial valve leaflet is a trileaflet bovine pericardial bioprosthetic valve leaflet, which is connected to the inner frame membrane by suturing.

[0015] Preferably, the outer frame covering is provided with a semi-open window close to the aorta side, and the opening cross section is elliptical, with a major axis of 24 mm and a minor axis of 9 mm.

[0016] Therefore, the present application provides a "lantern-shaped" variable-diameter transcatheter artificial mitral valve stent, which has the following beneficial effects:

[0017] The present invention's "lantern-shaped," variable-diameter transcatheter mitral valve prosthesis comprises three components: a dynamically adjustable outer valve frame, an inner valve frame, and a connecting membrane. It is anchored by a negative-pressure suction cup at the valve annulus. A "semi-fenestrated" membrane design is employed on one side of the outer valve frame. This invention avoids left ventricular outflow tract obstruction caused by excessive diameter without damaging cardiac tissue, and provides sufficient resistance to displacement.

[0018] 2. The "lantern-shaped," variable-diameter transcatheter mitral valve stent is an adaptive, deformable structure designed based on the fundamental principles of valve displacement. The fundamental cause of stent displacement is the high pressure impact on the left ventricle during mitral valve closure, which causes the stent to move toward the atrium. Braided stents, due to their unique weaving process, exhibit excellent flexibility and flex resistance in the cardiovascular stent field. Leveraging these properties, this study employed a weaving process to create a slightly bulging "lantern" shape at the lower end of the outer stent. When ventricular pressure rises, the mitral annulus simultaneously causes the valve leaflets to contract. This "clamp" between the annulus and leaflets and the ventricular blood forms a "grip" around the stent, increasing the outer stent diameter and preventing upward displacement. This variable-diameter structure avoids damage to native cardiac tissue while maintaining a simple overall construction for easy implantation. When deformed, the annulus lies above the lantern-shaped belly. Greater ventricular pressure increases the stent diameter, providing greater resistance to displacement. As the stent diameter increases, the valve leaflets move along the upper edge of the braided structure on the ventricular side of the stent, mitigating the risk of left ventricular outflow tract obstruction associated with the excessive radial diameter of existing fixed stents. In addition, the mitral valve ring is compressed inward by about 10%-20% when the heart contracts. The negative pressure suction cup set at the contact position between the stent and the valve ring squeezes the suction cup to form a vacuum when the valve ring contracts, thereby enhancing the anchoring performance of the stent.

[0019] 3. The dynamically adjustable valve outer frame, located near the aorta, features a single-sided fenestration without a membrane. Because the connecting membrane on the stent surface prevents blood from penetrating, the semi-fenestrated design allows for better blood flow through the outer frame. The outer frame's mesh stent significantly reduces blood flow obstruction, minimizing the risk of left ventricular outflow tract obstruction. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of a "lantern-shaped" variable-diameter mitral valve stent disclosed in an embodiment of the present invention;

[0021] Figure 2This is a structural diagram of the combined inner and outer frames of the mitral valve stent disclosed in an embodiment of the present invention;

[0022] Figure 3 The mitral valve stent outer frame disclosed in the embodiment of the present invention;

[0023] Figure 4 The mitral valve stent inner frame disclosed in the embodiment of the present invention;

[0024] Figure 5 The mitral valve stent disclosed in the embodiment of the present invention can be connected to the membrane of the "semi-open window" design;

[0025] Figure 6 This is a schematic diagram of the connection between the inner frame and valve leaflets of the mitral valve stent disclosed in an embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of the braided structure of the mitral valve stent outer frame disclosed in an embodiment of the present invention;

[0027] Figure 8 This is a schematic diagram of the structure of the negative pressure suction cup at the annulus of the mitral valve stent disclosed in an embodiment of the present invention;

[0028] Figure 9 The negative pressure suction cup unit at the annulus of the mitral valve stent disclosed in the embodiment of the present invention;

[0029] Figure 10 This is a schematic diagram of the dynamic changes of the mitral valve stent disclosed in an embodiment of the present invention along with the cardiac cycle.

[0030] Reference numerals

[0031] 1. Valve outer frame; 2. External stent body; 21. Umbrella disc; 22. Variable diameter structure; 23. Negative pressure suction cup; 3. Semi-open window covering; 4. Valve inner frame; 41. Internal stent body; 42. Internal frame covering; 43. Artificial valve leaflet; 5. Connecting film. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further illustrated by the following examples.

[0033] Example 1

[0034] This embodiment provides a "lantern-shaped" variable-diameter transcatheter artificial mitral valve stent for transcatheter mitral valve replacement, which is implanted between the left atrium and the left ventricle. Figures 1 to 10, a dynamically changeable valve outer frame 1, a valve inner frame 4 and a connecting film 5; the dynamically changeable valve outer frame 1 includes a grid "lantern-shaped" outer frame body 2 and a semi-open window covering 3 arranged on the inner side of the outer frame body 2, using different manufacturing processes, the outer frame body 2 is divided into a laser-engraved asymmetric umbrella disc 21 on the atrial side, a woven variable diameter structure 22 on the ventricular side and a negative pressure suction cup 23 for reinforced anchoring at the valve ring, the dynamically changeable valve outer frame 1 is connected and sleeved on the outside of the valve inner frame 4; the valve inner frame 4 includes a grid-shaped inner frame body 41 and an inner frame covering 42 is arranged inside the inner frame body 41, and an artificial valve leaflet 43 is connected on the inside; the connecting film 5 covers the valve outer frame 1 and the valve inner frame 4 to prevent blood leakage; the outer frame removes the covering on one side to form a semi-open window covering 3 design, and the gap between the inner and outer frames is connected by a connecting film 5 located on one side.

[0035] During implantation, the stent is first loaded into a delivery system that can be delivered via the femoral artery or the apex of the heart. Once the stent reaches the space between the atria and ventricles, it is released. The stent's negative pressure suction cup 23 positions the native mitral valve annulus, while the stent is rotated so that the "semi-fenestrated" side is proximal to the aorta. The asymmetric atrial umbrella disc 21 adheres to the atrial myocardial surface, sealing any gaps and preventing complications such as paravalvular leaks.

[0036] In the optional scheme of this embodiment, it is more preferred that the valve inner frame 4 and the dynamically changeable valve outer frame 1 are made of nickel-titanium alloy material; the negative pressure suction cup 23 at the valve ring is preferably but not limited to silicone material, and is attached to the surface of the valve outer frame 1 by gluing or other means, and the connecting film 5 is preferably but not limited to a polymer coating.

[0037] In the optional scheme of this embodiment, it is more preferred that the stent body has a lantern-shaped structure, which is divided into a laser-engraved asymmetric umbrella disc 21 on the atrial side, a woven variable diameter structure 22 on the ventricular side, and a pressure suction cup for reinforcing anchoring at the valve ring, which is connected and sleeved on the outside of the valve inner frame 4.

[0038] In an alternative embodiment of this embodiment, the stent's atrial-side umbrella disc 21 is preferably formed from a circular array of 16 "petal-shaped" rhombus-like unit structures, connected by connecting ribs. The edges of the rhombus-like structures are smooth curves, with acute angles of 65° and obtuse angles of 115°. The umbrella disc 21 has an "S"-shaped cross-section, with an axial distance of 5mm from the top to the bottom of the umbrella disc 21, a cross-sectional diameter of 45mm at the top, and a bottom diameter of 30mm at the bottom.

[0039] In the optional solutions of this embodiment, it is more preferred that the 16 "petal-shaped" rhombus-like unit structures are not completely symmetrical. In order to better fit the left atrial structure, the side close to the aorta is higher than the side away from the aorta.

[0040] Among the optional solutions of this embodiment, it is more preferred that the variable diameter structure 22 woven on the ventricular side of the stent presents a lantern shape with a larger diameter in the middle section, and is woven from 32 nickel-titanium alloy wires with a weaving angle of 65°; the woven structure can achieve that as the pressure of the left ventricle changes, the diameter of the middle section of the stent will increase, thereby increasing the degree of anchoring with the mitral valve and providing sufficient stability.

[0041] Among the optional solutions of this embodiment, it is more preferred that the variable diameter structure 22 woven on the ventricular side of the stent has an overall "lantern-shaped" structure that is narrow at both ends and wide in the middle, with an upper cross-sectional diameter of 30 mm, an abdominal cross-sectional diameter of 38 mm, a bottom cross-sectional diameter of 27 mm, and a height of 11 mm.

[0042] In the optional scheme of this embodiment, it is more preferred that the end of the woven variable diameter structure 22 on the ventricular side has 16 connecting and fixing rings, and the end of the valve outer frame is provided with 16 connecting and fixing rings. The connecting and fixing rings of the variable diameter structure 22 and the 16 connecting and fixing rings of the dynamically changeable valve outer frame 1 are bound and can be assembled into the delivery system to perform transcatheter mitral valve replacement surgery.

[0043] In the optional scheme of this embodiment, it is more preferred that the negative pressure suction cup 23 for strengthening the anchoring at the valve ring is generally wide at the top and narrow at the bottom, with a bottom radius of 0.05mm and a top radius of 0.07mm. When the valve ring is in contact, the anchoring is strengthened by forming a negative pressure vacuum structure.

[0044] Among the optional solutions of this embodiment, it is more preferred that the negative pressure suction cup 23 cooperates with the 16 unit structures of the valve outer frame 1, totaling 16 groups of suction cup structures, with 17 suction cup units in each group, distributed in an "X" shape that is wide at the top and narrow at the bottom on the surface of the valve outer frame 1.

[0045] In the optional scheme of this embodiment, it is more preferred that the valve inner frame 4 of the stent is in a grid cylindrical shape and the internal coating is provided with an inner frame coating 42, and the inner side is connected to the artificial valve leaflet 43 by suturing; the cross-sectional diameters of the grid cylindrical inner stent body 41 are consistent, the inner diameter of the cross section is 27 mm, the outer diameter of the cross section is 28 mm, the wall thickness is 0.5 mm, and the height is 13 mm; the unit grid is rhombus-like, with 16 repeating units in a single row, and a total of 3 rows, which are connected in the middle by a rectangular connecting rod.

[0046] In the optional solution of this embodiment, more preferably, the inner side of the valve inner frame 4 of the stent is connected with an artificial valve leaflet 43, and the artificial valve leaflet 43 is a tri-leaflet bovine pericardial biological valve leaflet, which is connected to the inner stent covering by suturing.

[0047] In the optional scheme of this embodiment, it is more preferred that the connecting film 5 is coated on the surface of the dynamically changeable valve outer frame 1 and the inner frame; the dynamically changeable valve outer frame 1 is arranged on the outside of the inner frame, with a middle gap of 0-2mm, and a film is applied on the plane of the umbrella disc 21 on the atrial side of the outer frame to connect the valve inner frame 4 and cover the middle gap.

[0048] Among the optional solutions of this embodiment, it is more preferred that the semi-open window covering 3 is covered on the inside of the dynamically changeable valve outer frame 1, and a semi-open window design is adopted on the side close to the aortic valve. The opening cross-section is elliptical, with a major axis of 24 mm and a minor axis of 9 mm. When the diameter of the dynamically changeable valve outer frame 1 changes, the window design can effectively reduce the obstruction of the left ventricular outflow tract.

[0049] Among the optional solutions of this embodiment, it is more preferred that the junction of the atrial side umbrella disc 21 and the ventricular side braided structure of the dynamically changeable valve outer frame 1 is the valve ring anchoring area. After implantation, the valve ring fits into the concave part, and the stent is tightened when the valve ring contracts. The high pressure of the left ventricle impacts the bottom of the dynamically changeable valve outer frame 1 upward, and the ventricular side braided structure undergoes adaptive deformation, the diameter increases, and the anchoring is strengthened.

[0050] Therefore, the present application provides the above-mentioned "lantern-shaped" variable-diameter transcatheter artificial mitral valve stent, which adopts a unilateral window and non-membrane design on the dynamically changeable valve outer frame close to the aorta side, thereby reducing the vibration of the device caused by blood flow, and at the same time adopts a negative pressure suction cup to improve the device's anti-displacement ability.

[0051] In this specification, references to terms such as "an experimental example," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that experimental example or example are included in at least one experimental example or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same experimental example or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more experimental examples or examples.

[0052] Finally, it should be noted that the above experimental examples are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred experimental examples, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A "lantern-shaped" variable-diameter transcatheter mitral valve stent, characterized in that: The valve comprises an inner valve frame, an outer valve frame that changes dynamically and is sheathed on the outside of the inner valve frame, and a connecting film connecting the outer valve frame and the inner valve frame. The outer valve frame comprises a lantern-shaped outer stent body and an outer frame covering arranged on the inner side of the outer stent body. The outer frame covering is arranged near the aorta-side semi-open window. The grid lantern-shaped stent body comprises an atrial side umbrella disc, a ventricular side diameter-reducing structure, and a negative pressure suction cup connected to the atrial side umbrella disc and the ventricular side diameter-reducing structure and used to strengthen anchoring. The inner valve frame comprises a grid cylindrical inner stent body and an inner frame covering arranged on the inner side of the inner stent body. The inner side of the inner stent body is connected to an artificial valve leaflet. The diameter of the middle section of the ventricular side variable diameter structure is larger than the diameters on both sides, presenting a lantern structure with narrow ends and wide middle. There are 16 fixing rings at the end of the ventricular side reducing structure, and 16 fixing rings are set at the end of the valve inner frame. The fixing rings of the ventricular side reducing structure are bound and assembled with the fixing rings on the valve inner frame and then fixed to the delivery system.

2. A "lantern-shaped" variable-diameter transcatheter mitral valve prosthesis according to claim 1, characterized in that: The atrial side umbrella disc is composed of a circular array of 16 "petal-shaped" diamond-shaped unit structures, connected by connecting ribs in the middle, and the edges of the diamond-shaped unit structures are smooth curves.

3. The "lantern-shaped" variable-diameter transcatheter mitral valve stent according to claim 2, characterized in that: The diamond-like unit structure is higher on the side close to the aorta than on the side away from the aorta.

4. The "lantern-shaped" variable-diameter transcatheter mitral valve stent according to claim 1, characterized in that: The ventricular side variable diameter structure is woven from 32 nickel-titanium alloy wires with a weaving angle of 65°; the upper cross-sectional diameter is 30 mm, the abdominal cross-sectional diameter is 38 mm, the bottom cross-sectional diameter is 27 mm, and the height is 11 mm.

5. The "lantern-shaped" variable-diameter transcatheter mitral valve stent according to claim 1, characterized in that: The negative pressure suction cup cooperates with the 16-unit structure of the valve outer frame, totaling 16 groups of negative pressure suction cup structures, each group with 17 suction cup units, distributed in an "X" shape with wide top and narrow bottom on the surface of the valve outer frame.

6. The "lantern-shaped" variable-diameter transcatheter mitral valve stent according to claim 1, characterized in that: The inner bracket body is a grid columnar structure. The diameters of the cross sections of the inner bracket body are consistent. The unit grid is rhombus-like, with 16 repeating units in a single row, and a total of 3 rows, which are connected in the middle by a rectangular connecting rod.

7. The "lantern-shaped" variable-diameter transcatheter mitral valve stent according to claim 1, characterized in that: The artificial valve leaflet is a three-leaflet bovine pericardial bioprosthetic valve leaflet, which is connected to the inner frame membrane by suture.

8. The "lantern-shaped" variable-diameter transcatheter mitral valve stent according to claim 1, characterized in that: The outer frame covering is set at a semi-open window close to the aorta side, and the opening cross section is elliptical, with a long axis of 24 mm and a short axis of 9 mm.

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