HK1235261B - Method and design for a mitral regurgitation treatment device - Google Patents

Description

Methods and designs for mitral regurgitation treatment devices

Technical Field

The present invention relates to a mitral regurgitation treatment device and a method of using the same. The methods and devices treat mitral regurgitation by implanting the device at the aortic valve location and urging the subarterial septum and/or the anterior leaflet of the mitral valve toward the mitral valve.

Background

The human heart has four chambers and four valves. The heart valve controls the direction of blood flow. A well-functioning heart valve ensures that proper blood circulation is maintained during the heart cycle. Regurgitation, or leakage, of a heart valve occurs when the leaflets of the heart valve fail to come into full contact (coaptation) due to disease, such as congenital heart disease, torn chordae tendineae, chordae tendineae stretch, left ventricle enlargement, papillary muscle damage, damage to the valve structure caused by interference, degeneration, calcification of the leaflets, annular strain, increased distance between papillary muscles, etc. Regardless of the cause, regurgitation affects heart function because it allows blood to flow back through the valve in the wrong direction. Depending on the degree of regurgitation, the regurgitation may have a self-destructive effect not only on cardiac function, but also on cardiac structures. On the other hand, abnormal cardiac structures may also be the cause of reflux, and these two processes may "work in concert" to accelerate abnormal cardiac function. A direct result of heart valve regurgitation is a reduction in positive cardiac output. Depending on the severity of the leak, the effect of the heart in pumping sufficient blood flow to other parts of the body may be diminished.

Referring to fig. 1, the mitral valve is a double-layered (bileaflet) valve in the heart, which is located between the Left Atrium (LA) and the Left Ventricle (LV). During diastole, a normally functioning mitral valve will open due to increased pressure from the left atrium when it is filled with blood (when preloaded). When the atrial pressure increases beyond that of the left ventricle, the mitral valve opens, encouraging blood flow to flow passivelyInto the left ventricle. The end of diastole is accompanied by atrial contraction which ejects the remaining blood that is transferred from the left atrium to the left ventricle. The mitral valve closes at the end of atrial contraction to prevent backflow of blood from the left ventricle to the left atrium. The open area of a human mitral valve is typically 4-6cm². There are two leaflets, an anterior leaflet and a posterior leaflet, which cover the opening of the mitral valve. The opening of the mitral valve is surrounded by a fibrous ring known as the mitral annulus. The two leaflets are circumferentially attached to the mitral annulus and can be hinged open and closed from the annulus during the cardiac cycle. In a normally functioning mitral valve, the leaflet is connected to the papillary muscle in the left ventricle by the chordae tendineae. When the left ventricle contracts, the pressure within the ventricle forces the mitral valve closed, while the chordae tendineae keep the two leaflets engaged (i.e., prevent the two valve leaflets from prolapsing into the left atrium and causing mitral regurgitation) and prevent the membrane from opening in the wrong direction (thereby preventing blood from flowing back into the left atrium). Mitral regurgitation may be caused by unsuccessful coaptation of the native mitral valve leaflets. In other words, as shown in fig. 1, when the mitral valve leaflets fail to engage, blood flows from the ventricles back into the left atrium during systole. Fig. 1 specifically shows a mitral valve with mitral regurgitation (during diastole), which has a longer a-P distance.

Currently, standard heart valve regurgitation treatment options include surgical repair/treatment and vascular clamps. Standard surgical repair or replacement procedures require open heart surgery, use of cardiopulmonary bypass, and cardiac arrest. Because of the invasive nature of these surgeries, death, stroke, bleeding, respiratory problems, kidney problems, and other complications are common enough to exclude many patients from the scope of the applicable surgery.

In recent years, vascular clamp technology has been developed by several facility companies. In this method, an implantable clamp made of a biocompatible material is inserted into the heart valve between the two leaflets, thereby clamping the intermediate portions of the two leaflets (primarily the a2 and P2 leaflets) together to prevent leaflet prolapse. However, practical applications of vascular clamps have revealed drawbacks such as difficulty in positioning, difficulty in removal once implanted incorrectly, recurrence of heart valve regurgitation, the need for multiple clamps in a single procedure, strict patient selection, etc.

In view of the foregoing, there is a great need to develop a novel medical device for treating mitral regurgitation. None of the medical devices available to date completely address this need. It is an object of the present invention to provide a device and a method for a physician which avoids invasive surgery and alternatively provides a medical device which can be implanted by a catheter-based, less invasive procedure for the treatment of mitral regurgitation.

Disclosure of Invention

To achieve the object of the present invention, an aortic valve apparatus is provided which is implanted at the location of a native aortic valve of a patient to treat mitral regurgitation. The device has a frame with a toroidal support, an aortic flange extending from one end of the toroidal support, and a ventricular flange extending from the other end of the toroidal support, and the ventricular flange flares radially outward such that the diameter of the ventricular flange gradually increases until it reaches a ventricular end. The frame further includes a canopy frame member extending from less than 90% of a periphery of the ventricular end, and the canopy frame member is provided with one or more unit assemblies formed of struts connected to the ventricular end. When the frame is implanted in the aortic portion, the canopy frame member is located on a side of the peripheral wall of the ventricular end that is positioned closer to the patient's subintimal aorta such that the canopy frame member urges the subintimal aorta and/or anterior leaflet of the mitral valve in a direction toward the mitral valve. The device also includes a set of leaflets that are sutured into the interior of the frame and that replace the valve function of the patient's native aortic valve.

Accordingly, the present invention provides methods and devices for treating mitral regurgitation. The methods and devices of the present invention treat mitral regurgitation by implanting the device inside the aortic valve and using the canopy member to urge the infraaortic septum and/or anterior leaflet of the mitral valve toward the mitral valve, thereby reducing the size of the mitral annulus (especially the a-P distance) and improving coaptation of the native mitral valve.

Drawings

Fig. 1 shows a human heart showing the mitral valve with mitral regurgitation.

Fig. 2 shows a human heart with the device of the invention implanted in the aortic position.

Fig. 3 is a schematic perspective view of an apparatus according to an embodiment of the present invention.

Fig. 4 is a schematic perspective view of the frame of the device of fig. 3.

Fig. 5 is a side perspective view of the frame of fig. 4.

Fig. 6 is a schematic top view of the frame of fig. 4.

Fig. 7 is a bottom schematic view of the frame of fig. 4.

FIG. 8 is a perspective schematic view of a possible lobe and skirt assembly that may be used with the device of FIG. 3.

Figures 9A-9C illustrate the delivery of the device of figure 3 using a transfemoral approach.

Fig. 10A-10B illustrate a delivery procedure of the device of fig. 3 using a transapical approach.

Detailed Description

The following detailed description is of the best presently contemplated mode of carrying out the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of embodiments of the invention. The scope of the invention is best defined by the appended claims. In certain instances, detailed descriptions of well-known devices and mechanisms are omitted so as not to obscure the description of the present invention with unnecessary detail.

In recent years, several transcatheter aortic valve replacement devices (TAVI) have been developed and are commercially available. These commercially available transcatheter aortic valve devices have shown some advantageous clinical advantages and have been widely used worldwide to treat patients with aortic valve disorders. Currently, transcatheter aortic valve devices may be delivered through the femoral artery or transapical, or through other arteries in the body. Clinical evidence has shown that transcatheter aortic valve replacement surgery is a safe and effective procedure.

The present invention provides a method and design for a mitral regurgitation treatment device 20 that treats mitral valve regurgitation by implanting the device into the aortic valve and urging the subintimal space of the aorta and/or the anterior leaflet of the mitral valve in the direction of the mitral valve by a canopy member 22 in the device to reduce the size of the mitral valve annulus, thereby improving coaptation of the native mitral valve leaflets. The canopy frame member 22 of the device may also reduce the size of the mitral annulus (especially the a-P distance) by pushing/supporting the subarterial septum or anterior leaflet of the mitral valve, thereby treating mitral regurgitation. Conventional aortic valve replacement procedures can be used in the method of the present invention to deliver a new device for mitral regurgitation treatment. Once the new device 20 is implanted in the aortic position, the canopy member 22 can push against the annulus of the inferior aortic septal/anterior leaflet/mitral valve to reduce the a-P distance of the mitral valve and improve coaptation of the leaflets of the mitral valve.

Fig. 2 shows the native mitral valve with a smaller a-P distance after the inventive device 20 is implanted in the aortic valve location. The canopy member 22 of the device 20 pushes the anterior structure of the mitral valve toward the posterior side and decreases the a-P distance. During systole, the leaflets of the mitral valve can coapt properly (and mitral regurgitation is reduced or eliminated).

The device 20 is shown in more detail in fig. 3-8. The device 20 includes a frame 24, a set of leaflets 26 sutured into the interior of the frame 24, and a skirt 28 to prevent leakage of the valve lumen wall, reduce trauma to surrounding sites, and promote tissue growth and healing.

The frame 24 has an aortic flange 30, an annular holder 32, and a ventricular flange 34. The aortic, annular, and ventricular flanges 30, 32, 34 may be made of nitinol superelastic material or stainless steel, cobalt-chromium based alloys, titanium and its alloys, and other biocompatible materials that are self-expandable or balloon expandable. Other polymeric biocompatible materials may also be used to fabricate these components of the device 20. For example, the frame 20 may be laser cut from tubing of metal or polymeric material. The cut structure will then be subjected to shape setting, micro-blasting, and electropolishing to achieve the desired profile/shape, as shown in fig. 4. Alternatively, the frame may be manufactured from a flat sheet and then rolled to the desired shape.

The aortic flange 30 is adapted to be placed in the aorta of a patient on the outflow side of the aortic valve, and a portion of the aortic flange 30 extends inside the aorta. The aortic flange 30 may contain a ring of frame elements 36, the frame elements 36 being made up of interconnected struts 40. The aortic flange 30 may have a surface area equal to or greater than the aortic annulus area.

The annular holder 32 serves as an anchoring structure and may interact with the annulus, native leaflets, and other intra-cardiac structures, or sub-valvular structures, to provide the desired anchoring effect. Referring to fig. 2 and 4, the annular holder 32 may be provided with a generally cylindrical body comprised of a plurality of frame cells 36, and the frame cells 46 comprised of interconnected struts 40.

The ventricular flange 34 extends from the ventricular end of the annular stent 32 and is radially expandable to the outside, thereby allowing the ventricular flange 34 to continue to increase in diameter until it reaches its ventricular end 38, where its diameter is greatest. The ventricular end 38 may be defined by the tip of the frame cell 36 closest to the ventricle. The ventricular flange 34 may contain a final ring of struts 48, the struts 48 defining the frame cells 36 of the annular stent 32 closest to the ventricle, and the struts 48 being flared outwardly. Radiopaque markers may be incorporated into the ventricular flange 34 to provide visual aids to assist in positioning during delivery of the device 20 and to continue with subsequent implantation. In use, the ventricular flange 34 and a portion of the height of the annular shelf 32 may be covered with a biocompatible polymeric fiber, fabric or other biocompatible material to provide a sealing effect around the device 20 and to promote tissue growth and healing.

The canopy member 22 extends from a portion of the perimeter wall/boundary of the chamber end 38 and may be made of the same material as the remainder of the frame 20 or laser cut. The canopy frame assembly 22 may be implemented in the form of one or more cell assemblies 42, the cell assemblies 42 being comprised of struts 44 connected to the tips of the individual grid cells at the ventricular end 38. The canopy member 22 is located on the side of the peripheral wall of the ventricular end 38 closer to the subintimal aorta. Various forms of radiopaque markers or coils may be integrated into the canopy frame assembly 22 for viewing, positioning, or direct placement of the device 20 and the canopy frame assembly 22 during surgery and subsequent implantation procedures. The canopy component 22 extends along 1% to 90% of the perimeter wall of the chamber end 38. The cell assembly 42 is preferably provided with a diameter greater than the outer diameter of the ventricular end 38 and is capable of being bent outwardly. In the embodiment shown in fig. 3-7, the struts 44 forming the canopy component 22 project radially outward from the ventricular end 38 in a recessed manner such that the tips of the cell assemblies 42 extend radially inward from the largest diameter portions of the struts 44. The cell assembly 42 may be sized smaller, larger, or equal to the mesh cells 36 in the annulus support 32, depending on the amount of flexibility desired. Radiopaque markers may be incorporated into the annulus support 32, and/or the ventricular flange 34, and/or the canopy frame assembly 22 to assist in positioning the device 20 during delivery. In addition, there may be more than one turn of the cell assembly 42. For example, providing additional turns of the cell assembly 42 will provide different mechanical characteristics to the canopy frame assembly 22. for example, by adjusting the size of the cell assembly 42, the canopy frame assembly 22 can be either b more flexible than other portions of the frame or more rigid than other portions. In addition, the cell assembly 42 may be smaller in size. As another alternative, the unit assemblies 42 in different rings may have different sizes.

The width of each strut 40 may be in the range from 0.2mm to 2.5mm and the thickness of each strut 40 may be in the range from 0.1mm to 0.75 mm. The length of each grid cell 36 may be in the range from 2mm to 25 mm. The number of grid cells 36 along the circumferential wall of the annulus support 32 may range from 3 to 20.

Fig. 4 illustrates a range of general sizes or geometries for each component of the device 20. The aortic flange 30 may have a circular profile or a profile other than perfectly circular. When the aortic flange 30 has a circular profile, the diameter of the aortic portion may be in the range from 12mm to 50 mm. If the aortic flange 30 has a profile other than perfectly circular, its major axis may be in the range from 20mm to 50mm and its minor axis may be in the range from 12mm to 40 mm. Further, the height H1 of the aortic flange 30 may be in the range from 0.5mm to 50 mm. At the upper aortic end of the aortic flange 30, each of the grid cells 46 defining the aortic flange 30 has peaks and valleys and a rounded atraumatic tip 44 on each of its peaks. If desired, the aortic flange 30 may be completely or partially covered by fibers or tissue material, or a composite of tissue and fiber material. The aortic flange 30 may have barbs or pins on its outer surface facing side to help catch the aortic wall when needed.

The annular holder 32 may have a height H2 in the range from 5mm to 60 mm. The cross-sectional profile of the annular holder 32 can be a complete circular shape or a profile other than a circular shape. When the annular holder 32 has a fully circular profile, its diameter may range from 12mm to 50 mm. When the annulus support 32 has a profile other than a circular shape, its long axis may be in the range from 15mm to 50mm and its short axis may be in the range from 12mm to 45 mm. The lower portion of the annular holder 32 (i.e., the portion closer to the side of the ventricle) may be covered in whole or in part with a fabric or tissue material, or a composite of a fabric and a fabric material. For example, one portion of the annular holder 32 may be covered with fabric and another portion of the annular holder 32 may be covered with tissue, or vice versa. In use, the fibrous material and tissue may be first sutured/attached together or separately sutured/attached to the lower portion of the annular holder 32. The lower portion of the annular holder 32 may be covered along one surface (i.e., the inner or outer surface), or along both surfaces (i.e., the inner and outer surfaces). At the bottom (opposite the ventricle) end of the annular holder 32, each grid cell 36 transitions to the ventricular flange 34. The ventricular flange 34 may have a height H3 in the range from 1mm to 20 mm. The cross-sectional profile of the ventricular flange 34 may be a complete circular shape or a profile other than a circular shape. When the ventricular flange 34 has a fully circular profile, its diameter may be in the range from 12mm to 60 mm. When the ventricular flange 34 has a profile other than a circular shape, its long axis may be in the range from 15mm to 60mm and its short axis may be in the range from 12mm to 50 mm. The ventricular flange 34 may have a tapered shape. For example, the end attached to the annular holder 32 may have a diameter that is smaller than the diameter of the ventricular end of the ventricular flange 34.

The canopy frame member 22 may have a height H4 in a range from 1mm to 30 mm. Preferably, the height H4 is about 50% to 150% of the height H3, while being about 10% to 70% of the height H2.

Fig. 8 illustrates an exemplary configuration of a lobe and skirt assembly, which may be a tri-lobed design, that may be used with the device 20. Three lobes 26 may be cut from the fixed tissue or polymer material. The leaflets 26 can be sewn together by a stitching operation along stitch lines 27 and then sewn together with skirt material 28 to form the leaflet and skirt assembly. The lobe and skirt assembly may then be incorporated into the frame 24 by stitching or other mechanical means.

The leaflets 26 may be made of treated pericardial tissue, such as bovine or porcine tissue, or other biocompatible polymeric materials. The leaflets 26 may also be formed of thin-walled biocompatible metal components (e.g., stainless steel, cobalt-chromium based alloys, nitinol, tantalum, and titanium, etc.) or biocompatible polymeric materials (e.g., polyisoprene, polybutadiene and copolymers thereof, neoprene and nitrile rubber, polyurethane elastomers, silicone rubber, fluoro and fluoro silicone rubber, polyester, and PTFE, etc.). The leaflets may also be provided with a drug or biologic coating to enhance their performance, prevent thrombosis, and improve vascular endothelial proliferation. The lobes on the device 20 may also be pre-treated or provided with a surface coating to prevent calcification.

The leaflets 26 may be incorporated into the frame 24 by mechanical weaving, suture stitching, and chemical, physical, or adhesive attachment methods. The leaflets 26 may also be covered with drugs or other biological agents to prevent blood clot formation in the heart. An anti-calcification material may also be coated or disposed on a surface thereof to prevent calcification.

The skirt 28 may be made of treated tissue or a polymeric material, or a composite of both materials.

The device 20 may be delivered to the aortic site in a manner similar to that of current Transcatheter Aortic Valve (TAVI) replacement devices. The device 20 may be compressed to a lower profile (see fig. 9A) and loaded onto a delivery system comprising a delivery system cannula 60 and a delivery catheter 62 and then delivered to a target site by a non-invasive medical procedure, such as by using the delivery catheter 60 in a transapical, transfemoral, or radial procedure, or in the carotid artery. Once it reaches the target implantation site, the device 20 can be released from the delivery sleeve 60 and can be expanded to its normal (expanded) profile by inflation of a balloon (for balloon-expandable frames 24) or by elastic energy stored in the device (for devices with self-expandable frames 24). The device 20 may be pushed out of the delivery catheter 62 or the delivery catheter 62 may be withdrawn to release the device 20.

During release of the device 20 from the delivery system, the components of the device 20 will be sequentially released from the delivery system. For example, during transapical delivery, as shown in fig. 10A-10B, the aortic flange 30 will be deployed first from the delivery sleeve 60, followed by the annular shelf 32, the ventricular flange 34, and then the canopy frame assembly 22, in that order. Conversely, during transfusions through the femoral artery, as shown in fig. 9B-9C, the canopy frame assembly 22 will be deployed first, followed by the ventricular flange 34, the annular shelf 32, and then the aortic flange 30, in that order. The procedure may be performed under guidance from X-rays and/or TEE, ICE, or other known imaging techniques. During delivery, the orientation of the delivery system and the device 20 will be controlled such that when the device 20 is released from the delivery system, the canopy assembly 22 can be precisely positioned in the subintimal area to urge the anterior mitral valve leaflet toward the mitral valve. The pushing action/force from the canopy frame assembly 22 may also reshape the mitral annulus (e.g., reduce the a-P distance of the mitral valve, etc.) so that the native mitral valve leaflets may better engage and function.

The foregoing detailed description is of the best mode presently contemplated for carrying out the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of embodiments of the invention. The scope of the invention is best defined by the appended claims. In certain instances, detailed descriptions of well-known devices, components, mechanisms and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

Claims (16)

1. An aortic valve apparatus comprising:

a frame for implantation in the aortic portion having an annular stent, an aortic flange extending from one end of the annular stent for placement in the aorta, and a ventricular flange extending from the other end of the annular stent for placement in the left ventricle; the ventricular flange flaring radially outward such that the ventricular flange gradually increases in diameter until it reaches the ventricular end;

the frame further comprising a canopy frame assembly extending from less than 90% of the perimeter wall of the ventricular end, and the canopy frame assembly being provided with one or more unit assemblies of struts connected to the ventricular end, the canopy frame assembly being positioned on a side of the perimeter wall of the ventricular end that is positioned closer to the patient's subintimal aortic space when the frame is implanted in the aortic portion for reducing the size of the mitral valve annulus; and

a set of leaflets sewn into the interior of the frame.

2. The apparatus as claimed in claim 1, wherein the struts constituting the tent frame assembly are extended radially outward from the ventricular end in a concave manner such that tips of the unit assemblies are extended radially inward.

3. The apparatus of claim 1, wherein the annulus support is defined by a plurality of grid cells, and wherein the cell assembly has a smaller size than the grid cells in the annulus support.

4. The apparatus of claim 1, wherein the annulus support is defined by a plurality of grid cells, and wherein the cell assembly has a larger size than the grid cells in the annulus support.

5. The apparatus of claim 1, wherein the annulus support is defined by a plurality of grid cells, and wherein the cell assembly has the same dimensions as the grid cells in the annulus support.

6. The device of claim 1, wherein the ventricular flange is defined by a plurality of grid cells and the ventricular end is defined by a tip of the grid cell.

7. The device of claim 6, wherein a portion of the ventricular flange and the annular scaffold are highly covered by biocompatible polymer fibers, tissue, or other biocompatible material.

8. The apparatus of claim 1, wherein the canopy frame assembly has a height and the annulus support has another height, and wherein the canopy frame assembly has a height that is 10% to 70% of the height of the annulus support.

9. An aortic valve apparatus to be implanted at the location of a native aortic valve of a patient to treat mitral regurgitation, comprising:

a frame for implantation in the aortic portion having an annular stent, an aortic flange extending from one end of the annular stent for placement in the aorta, and a ventricular flange extending from the other end of the annular stent for placement in the left ventricle; the ventricular flange flaring radially outward such that the ventricular flange gradually increases in diameter until it reaches the ventricular end;

the frame further comprising a canopy frame assembly extending from less than 90% of the perimeter wall of the ventricular end over a portion of the perimeter wall of the ventricular end, the canopy frame assembly provided with one or more unit assemblies of struts connected to the ventricular end, the canopy frame assembly positioned on a side of the perimeter wall of the ventricular end that is positioned closer to a patient's subintimal aorta when the frame is implanted in the aortic portion such that the canopy frame assembly urges an anterior leaflet of the mitral valve toward the mitral valve for reducing a size of a mitral valve annulus; and

a set of leaflets sutured into the interior of the frame, and which assume the valve function of the patient's native aortic valve.

10. The apparatus as claimed in claim 9, wherein the struts constituting the tent frame assembly are extended radially outward from the ventricular end in a concave manner such that tips of the unit assemblies are extended radially inward.

11. The apparatus of claim 9, wherein the annulus support is defined by a plurality of grid cells, and wherein the cell assembly has a smaller size than the grid cells in the annulus support.

12. The apparatus of claim 9, wherein the annulus support is defined by a plurality of grid cells, and wherein the cell assembly has a larger size than the grid cells in the annulus support.

13. The apparatus of claim 9, wherein the annulus support is defined by a plurality of grid cells, and wherein the cell assembly has the same dimensions as the grid cells in the annulus support.

14. The device of claim 9, wherein the ventricular flange is defined by a plurality of grid cells and the ventricular end is defined by a tip of the grid cell.

15. The device of claim 14, wherein a portion of the ventricular flange and the annular scaffold are highly covered by biocompatible polymer fibers, tissue, or other biocompatible material.

16. The apparatus of claim 9, wherein the canopy frame assembly has a height and the annulus support has another height, and wherein the canopy frame assembly has a height that is 10% to 70% of the height of the annulus support.