Lantern-shaped variable-diameter transcatheter artificial mitral valve stent

Abstract

The invention discloses a lantern-shaped variable-diameter transcatheter artificial mitral valve stent, and belongs to the technical field of medical instruments. Comprising a lantern-shaped outer stent body and an outer stent covering film, the outer stent covering film is arranged close to an aorta side semi-open window, and the outer stent covering film is arranged close to the aorta side semi-open window. The grid lantern-shaped support body comprises an atrial side umbrella disc, a ventricular side variable diameter structure and a negative pressure suction cup which is connected with the atrial side umbrella disc and the ventricular side variable diameter structure and used for strengthening anchoring. The valve inner frame comprises a grid barrel-shaped inner frame body and an inner frame covering film, and the inner side of the inner frame body is connected with an artificial valve leaflet. By means of the lantern-shaped design of the outer stent and the valve ring suction cup for assisting anchoring, the problem that an artificial mitral valve replaced through a catheter is difficult to anchor is solved, and the problem that a left ventricular outflow tract is prone to being blocked after a covered stent is implanted is solved through the design that the single side of the dynamically-changeable valve outer stent is not covered with a film.

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 related to a variety of heart diseases and degenerative changes. Epidemiological studies in Western countries have shown that MR is the valvular disease with the highest incidence rate among the elderly population aged 65 and above. For elderly patients with multiple systemic diseases, the surgical risk is high and the survival benefit is 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 geometry of the mitral valve annulus is saddle-shaped, rather than circular or D-shaped, and its structure is not located on a single plane. This complex geometric feature may result in incomplete matching between the valve and the annulus during prosthetic valve replacement surgery, thereby increasing the risk of paravalvular leak after surgery. The annulus is soft, and the high ventricular pressure during ventricular contraction makes it impossible for the prosthetic valve to provide sufficient friction, resulting in difficult anchoring 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 solve the above problems, multiple TMVR valve products are under development around the world. A variety of structures have been proposed, such as apical rope fixation, where the rope is bound to the stent and then penetrates the myocardium and is fixed on the outer surface of the apex, but this method has not been widely recognized because it damages the myocardial tissue; radial interference and barb penetrating valve fixation methods, although they can provide better anchoring performance, excessive radial degree may hinder the left ventricular outflow tract, and barbs piercing the valve leaflets may cause secondary damage due to frequent traction of the heartbeat; although the native valve capture and ring-in-valve anchoring methods do not harm the heart tissue, the experiment is hindered by the chord structure under the native valve, and the implantation success rate of this anchoring method is low. In summary, the anti-displacement design of the artificial mitral valve stent is still imperfect. Relying on increasing the diameter to resist displacement will compress the left ventricular outflow tract, and the additional auxiliary anchoring device will damage the heart tissue and make 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 dynamically changes 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 close to the semi-open window on the aorta side, the grid lantern-shaped stent body includes an atrial side umbrella disc, a ventricular side diameter-changing structure, and a negative pressure suction cup connecting the atrial side umbrella disc and the ventricular side diameter-changing 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, and the inner side of the inner stent body is connected to an artificial valve leaflet.

[0008] Preferably, the atrial side umbrella disk is formed by a circular 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 rhombus-like unit structure is higher on the side close to the aorta than on the side far from the aorta.

[0010] Preferably, the diameter of the middle section of the ventricular side reducer 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 cross-sectional diameter is 30mm, the abdominal cross-sectional diameter is 38mm, the bottom cross-sectional diameter is 27mm, and the height is 11mm.

[0011] Preferably, there are 16 fixing rings at the end of the ventricular side reducing structure, and 16 fixing rings are arranged 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 on the surface of the valve outer frame in an "X" shape that is wide at the top and narrow at the bottom.

[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, there are 16 repeating units in a single row, and there are 3 rows in total, which are connected in the middle by a rectangular connecting rod.

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

[0015] Preferably, the outer frame coating is disposed near the semi-open window on 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] 1. The "lantern-shaped" variable diameter transcatheter artificial mitral valve stent of the present invention includes three parts: a dynamically changeable valve outer frame, a valve inner frame and a connecting film. The negative pressure suction cup at the valve ring is used to strengthen the anchoring. At the same time, a "semi-open window" covering design is adopted on one side of the valve outer frame. The present invention can avoid the problem of left ventricular outflow tract obstruction caused by excessive diameter without damaging the heart tissue, and provide sufficient anti-displacement ability.

[0018] 2. The "lantern-shaped" variable diameter transcatheter artificial mitral valve stent is an adaptive deformable structure proposed based on the basic principle of valve displacement. The fundamental reason for the displacement of the valve frame is the high pressure impact of the left ventricle when the mitral valve is closed, which causes the stent to move toward the atrial side. Because the braided stent exhibits excellent flexibility and bending resistance in the field of cardiovascular stents due to its unique braiding process. Based on this characteristic, this study uses a braiding process to make the lower end of the outer frame into a "lantern shape" with a slightly expanded bottom. When the ventricular pressure increases, the mitral valve ring simultaneously drives the valve leaflets to contract, and the valve ring leaflets and ventricular blood form a "clamp" on the stent, so that the diameter of the outer frame increases, thereby preventing upward displacement. This variable diameter structure avoids damage to the native tissue of the heart, and the overall structure is simple and easy to implant. When deformation occurs, the valve ring is above the lantern-shaped abdomen. The greater the ventricular pressure, the larger the diameter of the stent, and the stronger the anti-displacement ability provided. When the stent diameter increases, the valve leaflets move along the upper edge of the braided structure on the ventricular side of the stent, alleviating the risk of left ventricular outflow tract obstruction caused by the excessive radial diameter of the stent of the existing fixed structure. In addition, the mitral valve ring is compressed inward by about 10%-20% when the heart contracts. The negative pressure suction cup provided at the position where the stent contacts 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. On the side of the dynamically changeable valve outer frame close to the aorta, a single-side window without film covering design is adopted. Since the connecting film on the surface of the stent has the function of preventing blood from penetrating, the semi-open window design allows blood to flow through the outer frame better. The mesh stent of the outer frame greatly reduces the obstruction of blood flow and can reduce 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 stent disclosed in an embodiment of the present invention;

[0021] Figure 2This is a structural diagram of the 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 "half-open window" design of the mitral valve stent connectable to the film disclosed in the embodiment of the present invention;

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

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

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

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

[0029] Fig.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 support body; 21. Umbrella disc; 22. Variable diameter structure; 23. Negative pressure suction cup; 3. Semi-open window covering; 4. Valve inner frame; 41. Internal support 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 coating 3 arranged on the inner side of the outer frame body 2, and adopts different manufacturing processes. The outer frame body 2 is divided into a laser-engraved asymmetric umbrella disk 21 on the atrial side, a woven variable diameter structure 22 on the ventricular side and a negative pressure suction cup 23 for reinforcing 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 cylindrical inner frame body 41 and an inner frame coating 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 coating is removed on one side of the outer frame to form a semi-open window coating 3 design, and the gap between the inner and outer frames is connected by a connecting film 5 located on one side.

[0035] When implanting this embodiment, the valve stent is first loaded into a delivery system that can be delivered through the femoral artery or the apex of the heart, and the valve stent is released after reaching between the atrium and the ventricle. The negative pressure suction cup 23 of the stent locates the native mitral valve ring, and the stent is rotated at the same time so that the "half-open window" side is located near the proximal end of the aorta. The asymmetric atrial side umbrella disc 21 is attached to the myocardial surface of the atrium to cover the gap that does not fit, and prevent the occurrence of complications such as paravalvular leakage.

[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, 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 disk 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 the optional scheme of this embodiment, it is more preferred that the atrium side umbrella disk 21 of the stent is composed of 16 "petal-shaped" diamond-like unit structures in a circumferential array, connected in the middle by connecting ribs. The edge of the diamond-like structure is a smooth curve, with an acute angle of 65° and an obtuse angle of 115°; the cross section of the umbrella disk 21 is "S" shaped, with an axial distance of 5mm from the top to the bottom of the umbrella disk 21, a top disk cross-section diameter of 45mm, and a bottom disk bottom diameter of 30mm.

[0039] In the optional scheme 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 far from the aorta.

[0040] Among the optional schemes 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 in the left ventricle changes, the diameter of the middle section of the stent will increase, thereby increasing the degree of anchoring to the mitral valve and providing sufficient stability.

[0041] Among the optional schemes 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 a cross-sectional diameter of 30 mm at the upper end, a cross-sectional diameter of 38 mm at the abdomen, a cross-sectional diameter of 27 mm at the bottom end, 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, and 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 to 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 wider at the top and narrower 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 schemes 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, each group of 17 suction cup units, distributed on the surface of the valve outer frame 1 in an "X" shape that is wide at the top and narrow at the bottom.

[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 with an artificial valve leaflet 43 by suturing; the diameters of the cross sections 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 3 rows in total, which are connected in the middle by a rectangular connecting rod.

[0046] In the optional scheme 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 three-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 sleeved 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 disk 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 schemes 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, and 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 schemes of this embodiment, it is more preferred that the junction between 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 the concave part, and the bracket 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 reduces the vibration of the device caused by blood flow by adopting a single-sided window and non-film design on the dynamically changeable valve outer frame close to the aorta side, and at the same time adopts a negative pressure suction cup to improve the device's anti-displacement ability.

[0051] In the description of this specification, the description with reference to the terms "an experimental example", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the experimental example or example are included in at least one experimental example or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same experimental example or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more experimental examples or examples in a suitable manner.

[0052] Finally, it should be noted that the above experimental examples are only used to illustrate the technical solution of the present invention rather than to limit it. 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 solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A "lantern-shaped" variable-diameter transcatheter artificial mitral valve stent, characterized in that: It includes 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 frame body and an outer frame covering arranged on the inner side of the outer frame body. The outer frame covering is arranged close to the semi-open window on the aorta side. The grid lantern-shaped stent body includes 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 valve inner frame includes a grid cylindrical inner frame body and an inner frame covering arranged on the inner side of the inner frame body. The inner side of the inner frame body is connected with an artificial valve leaflet.

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

3. A "lantern-shaped" variable-diameter transcatheter artificial mitral valve stent according to claim 1, characterized in that: The rhombus-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 artificial mitral valve stent according to claim 1, characterized in that: The diameter of the middle section of the ventricular side reducer 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 cross-sectional diameter is 30mm, the abdominal cross-sectional diameter is 38mm, the bottom cross-sectional diameter is 27mm, and the height is 11mm.

5. The "lantern-shaped" variable-diameter transcatheter artificial mitral valve stent according to claim 1, characterized in that: There are 16 fixing rings at the end of the ventricular side reducing structure, and 16 fixing rings are arranged 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.

6. The "lantern-shaped" variable-diameter transcatheter artificial 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 on the surface of the valve outer frame in an "X" shape that is wide at the top and narrow at the bottom.

7. The "lantern-shaped" variable-diameter transcatheter artificial mitral valve stent according to claim 1, characterized in that: 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 repeated units in a single row, and 3 rows in total, which are connected in the middle by a rectangular connecting rod.

8. The "lantern-shaped" variable-diameter transcatheter artificial 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 suturing.

9. A "lantern-shaped" variable-diameter transcatheter artificial mitral valve stent according to claim 1, It is characterized in that The outer frame covering is set close to the aorta side with a semi-open window, the opening section is elliptical, the long axis is 24mm, Short axis 9mm.

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