Methods and apparatus for heart valve leaflet modification

Abstract

To provide systems, devices and methods for percutaneously modifying leaflets within the heart, thereby facilitating further repair or replacement.SOLUTION: In some embodiments, the leaflets are cut. In other embodiments, the leaflets are removed either in part or in whole. The modifications to the leaflets may be made in conjunction with a prosthetic valve or independently.SELECTED DRAWING: Figure 5G

Description

Related Applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 62 / 933,007, filed on November 8, 2019, entitled "Heart Valve Leaflet Modification", the entire disclosure of which is incorporated herein by reference.

Technical Field

[0002] The present disclosure relates to novel and advantageous transcatheter delivery valve repair devices. More specifically, the devices in the present disclosure address problems related to the treatment of pathologies involving heart valves such as the mitral valve, aortic valve, pulmonary valve, and tricuspid valve.

Background Art

[0003] The background description provided in the present disclosure is generally intended to present the context of the present disclosure. The achievements of the inventors of the present application within the scope described in this background art section, and aspects of the description that may not be recognized as prior art at the time of filing are not admitted as prior art to the present disclosure, either explicitly or implicitly.

[0004] Valvular heart disease is one of the common cardiovascular diseases that may be composed of stenosis (i.e., narrowing) affecting the patient's heart valve, insufficiency (i.e., incompetence or regurgitation), or a combination of these two diseases. When valvular heart disease develops, each chamber of the heart undergoes harmful remodeling, leading to heart failure, exacerbation, and decreased survival rate.

[0005] Generally, open surgery is performed, but there are many patients who are not candidates for surgery due to the risks of the operation. In many cases, a minimally invasive approach is preferred for treatment to minimize the perioperative and postoperative recovery.

[0006] Transcatheter treatments for valvular heart disease include methods to repair the valve and complete replacement procedures that implant an artificial valve inside the patient's valve. There are also cases where a prosthesis is transplanted into an existing prosthesis that is malfunctioning or has fallen off (for example, valve-in-valve).

[0007] In transcatheter treatment for valvular heart disease, native leaflets or artificial patches are generally preserved. Unfortunately, however, the native leaflets or artificial patches left in place may interfere with subsequent repair or replacement success. In some cases, the risk of interference is too high to allow successful transcatheter treatment. Also, interference may not be noticed until a valve is implanted.

[0008] As a specific example, there is transcatheter mitral valve replacement. This involves transplanting a valve prosthesis into either the patient's native mitral valve apparatus or an artificial valve previously implanted. Since the mitral annulus is close to the left ventricular outflow tract, in transcatheter mitral valve replacement, native or artificial leaflets may be positioned in the direction of the systolic flow. The positioning of native leaflets or artificial patches forward can cause severe left ventricular outflow tract obstruction and endanger life. Summary and Objectives of the Invention

[0009] The following aims to provide a basic understanding of one or more embodiments of the present disclosure by presenting a simplified summary of such embodiments. This summary is not an extensive overview of all contemplated embodiments, nor is it intended to identify key or decisive elements of all embodiments or to define the scope of any or all embodiments.

[0010] The present disclosure relates to systems and methods for percutaneously modifying the leaflets within the heart, thereby facilitating further repair of replacement. In some embodiments, the leaflets are cut. In other embodiments, part or all of the leaflets are removed. The present disclosure consists of a steerable guide catheter (SGC), a delivery catheter (DC), a cutting element (CU), a perforating member (P) having barbs or retention elements (B), which are disposed within the ventricle. The present disclosure describes a method for modifying the leaflets of the mitral valve, but these same methods and tools can be used on any leaflet within the heart prior to subsequent valve treatment (i.e., repair or replacement) or as a standalone treatment.

[0011] Although multiple embodiments are disclosed, still other embodiments of the present disclosure will be apparent to those of ordinary skill in the art from the following detailed description, which illustrates and describes exemplary embodiments of the invention. As will be fully understood, the various embodiments of the present disclosure are capable of modification in various obvious aspects, all without departing from the spirit and scope of the present disclosure. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.

[0012] One aspect of the invention is a leaflet modification device comprising a steerable guide catheter, a perforating element extendable from a distal end of the steerable guide catheter and having a tissue engagement mechanism, and a cutting element extendable from the distal end of the steerable guide catheter and expandable from a first configuration to a second configuration, wherein the cutting element and the perforating element are translatable relative to each other such that the leaflet is sandwiched between the cutting element and the perforating element and the cutting element is enabled to modify the leaflet.

[0013] Another aspect of the present invention is a system for modifying a native valve leaflet, comprising a steerable guide catheter, a delivery catheter extendable from the distal end of the steerable guide catheter, and a cutting element extendable from the distal end of the steerable guide catheter and expandable from a first configuration to a second configuration, the cutting element including a cutting unit having a distal intersection, a push rod, and a connecting member connecting the cutting unit to the push rod.

[0014] Another aspect of the present invention is a method for treating a valve leaflet, comprising advancing a cutting element through a catheter to a target valve leaflet, expanding the cutting element from a first configuration to a second configuration, engaging the valve leaflet with the cutting element, and modifying the valve leaflet with the cutting element. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] These and other aspects, features, and advantages of embodiments of the present invention will become apparent and be elucidated from the following description of embodiments of the present invention made with reference to the accompanying drawings.

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Embodiments for Carrying Out the Invention

[0058] Next, specific embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments described in this disclosure. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. The terms used in the detailed description of the embodiments shown in the accompanying drawings are not intended to limit the present invention. In the drawings, the same numbers indicate the same elements.

[0059] The present invention relates to the treatment of lesions of the aortic root and ascending aorta using a device deployed via a catheter. Although this disclosure discusses embodiments of the present disclosure with respect to a patient's aortic root and ascending aorta, the embodiments are applicable to any valve of the patient's heart and this disclosure should not be construed as limited to this application. The embodiments described in this disclosure may be applied to the repair of other valves and chambers of the human heart.

[0060] When used in a patient, the device of the present invention modifies the valve leaflets to reduce the risk of left ventricular outflow tract ("LVOT") obstruction and facilitate subsequent valve repair or replacement. This device is steerable to any part of any valve leaflet and can cut or remove some or all of the targeted part. From the perspective of the surgeon, the implantation of the device can be guided while evaluating in real time with echocardiogram or fluoroscopy. The cutting element can be of various shapes selected to fit the patient's biological structure and the requirements for facilitating subsequent valvular disease treatment.

[0061] The heart is typically composed of four valves: the mitral valve, aortic valve, pulmonary valve, and tricuspid valve. For the purpose of explanation, this disclosure focuses on the use of the device and method of the present invention for modifying the valve leaflets of the heart.

[0062] FIG. 1 is provided for reference and shows various parts of the human heart to establish some of the abbreviations used in this disclosure. The anterior mitral leaflet AML is part of the cardiac skeleton, near the aortic valve AV and near the left ventricular outflow tract LVOT. When mitral valve closure occurs due to systolic pressure, the proximity of the AML to the LVOT increases during diastole and decreases during systole. Thus, the systolic flow through the LVOT is not normally impeded by the AML.

[0063] As shown in FIG. 2, when a mitral valve replacement surgery is performed to replace the mitral valve with an artificial mitral valve PMV, the AML typically becomes externally fitted and fixed to the frame of the artificial valve. When the AML is fixed in this way, the systolic flow through the LVOT is obstructed, and such an obstruction can be life-threatening. In many cases, mitral valve replacement surgery, especially mitral valve replacement using catheter-based means, is not performed due to LVOT obstruction caused by AML fixation.

[0064] When performing an open surgery on a patient, in order to facilitate mitral valve treatment, the surgeon may excise the AML. The present invention is directed to devices and methods that can be used to modify the AML and thereby reduce the risk of LVOT obstruction. This modification changes the AML from its baseline state (FIG. 3A) to a configuration (FIG. 3B) having an embodiment of a modification portion 10 such that the forward portion and its free end allow blood flow through the cells of the artificial valve to be placed thereafter. In a non-limiting example of the embodiment shown in FIG. 3B, the modification portion 10 is only a cut that maintains coaptation during the systolic closure of the mitral valve. FIG. 4A is a plan view of the MV showing an example of the position of the modification portion 10 at the junction of the anterior mitral leaflet AML and the posterior mitral leaflet PML. In another embodiment, the modification is a partial or complete removal of the leaflet (FIG. 4B), in which case the use of the native mitral valve will be terminated in favor of implanting an artificial mitral valve.

[0065] Referring to FIGS. 5A-5G, an embodiment of the device and method of the present invention will be described. First, in FIG. 5A, an operable guide catheter 20 is guided into the left atrium and oriented such that the distal end 22 of the catheter 20 faces the anterior mitral leaflet AML. Those skilled in the art will understand that this method can be used to modify other anatomical valves and that this method is provided as a non-limiting example.

[0066] Next, as seen in FIG. 5B, the piercing element 30 is advanced from the distal end 22 of the steerable guide catheter 20. The piercing element 30 includes a tissue engagement mechanism 32 such as a barb or similar retention element, and guides to fix the AML in both the systolic phase (FIG. 5C) where the AML and PML are joined, and the diastolic phase (FIG. 5D) where the PML is directed away from the AML by the blood flow from the left atrium LA to the left ventricle LV. The piercing element 30 may include a hypodermic tube (not shown) for the placement of a guide wire through the AML.

[0067] Referring to FIGS. 5E and 5F, once the AML is fixed, the cutting element 40 advances through the delivery catheter 50 that is slidably accommodated within the steerable guide catheter 20 and engages the AML for modification. Examples of piercing methods that can be used include, for example, RF energy, mechanical force where the valve tip is closed and the needle tip is applied. Various embodiments of the cutting element 40 will be described in more detail below.

[0068] FIGS. 6A - 6F show various non - limiting examples of modifications that can be made to the AML (or other valve leaflets) according to the present invention. In FIG. 6A, the modification 10 is embodied as a single slit 12. FIG. 6B is a diagram showing a double slit 13. FIG. 6C is a diagram showing an elongated slit 14. FIG. 6D is a diagram showing a crown - shaped slit 15. FIG. 6E is a diagram showing a cross - shaped slit 16. FIG. 6F shows a wide slit 17 with tissue resection.

[0069] Next, referring to FIGS. 7A - 7H, an embodiment of the method of the present invention will be described in which the device of the present invention is used to modify the aortic valve AV. For reference, FIG. 7A shows the aortic valve AV connecting the left ventricle LV and the ascending aorta Ao in a closed state during diastole. FIG. 7B shows the open state of the aortic valve AV during systole, also for reference.

[0070] First, in FIG. 7C, an embodiment of the method of the present invention begins by guiding a steerable guide catheter 20 through the ascending aorta to a position behind the aorta and directing it toward the target valve cusp, and advancing a delivery catheter through the distal end 22 of the guide catheter 20. FIG. 7C shows the delivery catheter 50 advancing toward the left aortic cusp during diastole, and FIG. 7D shows the delivery catheter 50 maintaining its position during systole. The system of the present invention may be used to place the delivery catheter 50 in any one of the coronary cusps (i.e., the left coronary artery, the right coronary artery, or the non-coronary artery).

[0071] In FIG. 7E, the cutting element 40 is advanced from the delivery catheter such that the sharp distal intersection 42 pierces through the valve cusp. It may be advantageous to advance the delivery catheter 50 until it contacts the valve cusp to prevent buckling of the cutting element 40 and facilitate a more accurate placement. In at least some embodiments, the cutting element 40 is an ablation electrical element and may be energized to pass through the valve cusp. Other modes of cutting are known to those skilled in the art such as mechanical cutting, cryoablation cutting, laser cutting, RF cutting, ultrasonic cutting, electrosurgical cutting, etc., but are not limited thereto. In other embodiments, an additional piercing wire may be advanced integrally with the cutting element 40 immediately distal to the cutting element 40 to pass the cutting element 40 through the valve cusp. FIG. 7F shows the state where the cutting element 40 has passed through the valve cusp and has expanded into a deployed configuration to create a modification of the desired shape.

[0072] In FIG. 7G, the cutting element 40 retreats through the valve cusp in the deployed configuration to begin forming the modification, while being energized if applicable. In FIG. 7H, the cutting element 40 has passed through the valve cusp and a modified location has been formed.

[0073] FIG. 8 is a completed view of the modification 10 applied to the aortic valve cusp using the method of FIGS. 7A - 7H. The modification 10 consists of a single slit 18 formed in the middle of the valve cusp and spaced from the covering edge.

[0074] Next, referring to FIGS. 9A-9B, additional steps of the method are shown, which can be used, if desired, to create additional modified shapes using the same cutting element 40. In FIG. 9A, the steerable guide catheter 20 and the delivery catheter 50 are repositioned by rotation, bending, or extension to different positions on the valve tip with the cutting element 40 retracted from the valve tip, and then advanced beyond the valve tip as described above, or advanced using a previously formed slit. Thereafter, the cutting element 40 is retracted through the valve tip to form additional modifications.

[0075] Referring to FIGS. 10A-10F, non-limiting examples of modification 10 applied to the aortic valve using the aforementioned method are shown. FIG. 10A is a reference view of an unmodified aortic valve AV. FIG. 10B shows modification 10 in the form of a slit 100 that radially extends from the center of the valve tip to the middle of the valve tip. FIG. 10C shows a slit 101 formed in the center of the valve tip, oriented substantially parallel to the aortic valve periphery at a position away from the edge. FIG. 10D shows a slit 102 formed from the edge of the valve tip and running substantially parallel to the aortic valve periphery to a point within the valve tip. FIG. 10E shows a slit 103 that effectively leads to the ability to remove the aortic valve leaflet tissue portion X, extending from one free edge to another free edge.

[0076] Regarding various embodiments of the cutting element 40 of the present invention, attention is first directed to FIG. 11, which shows that the cutting element 40 generally comprises a cutting unit 44 having a distal intersection 42, a push rod 46 used to advance the cutting element 40 through the delivery catheter 50, and a connecting element 48 that connects the cutting unit 44 to the push rod 46.

[0077] The cutting unit 44 is generally a loop-shaped wire having a first configuration and a second deployed configuration. The second configuration is heat-set into the wire such that, in at least one embodiment, it becomes the second configuration upon release from the delivery catheter. In at least one embodiment, the wire is formed from a shape memory metal such as nitinol. In one embodiment, the cutting unit 44 is self-expanding and has a shape that allows engagement of the valve leaflets from one or both sides of the valve. In another embodiment, the cutting unit 44 has exposed elements for charging and cutting the valve leaflets. In yet another embodiment, the cutting unit 44 has a sharp tip for mechanically cutting the valve leaflets. In yet another embodiment, the cutting unit 44 facilitates modification by passing through the valve leaflets and then expanding or charging.

[0078] The cutting unit 44 can be modified into various shapes according to the anatomical structure of the heart valve and the planned subsequent treatment. FIGS. 12-15 are embodiments of the cutting element 40 that differ only in the shape of the cutting unit 44. FIG. 12 shows the cutting unit 44 in a second expanded configuration in which oval wings 60, 61 are formed. FIG. 13 shows the cutting unit 44 in a second expanded configuration in which oval wings 62, 63 are formed. FIG. 14 shows the cutting unit 44 in a second expanded configuration in which retracted wings 64, 65 are formed. FIG. 15 shows the cutting unit 44 in a second expanded configuration in which elongated retracted wings 66, 67 are formed.

[0079] Figures 16 and 17 are diagrams showing an embodiment of a cutting element 70 that utilizes a tether 72 to manually change the configuration of the cutting unit 44 from a first configuration to a second configuration. The cutting element 70 includes, as in other embodiments, a cutting unit 44 having a distal intersection 42, a push rod 46 used to advance the cutting element 40 through a delivery catheter 50, and a connecting element 48 that connects the cutting unit 44 to the push rod 46. The tether 72 extends from the proximal end of the catheter, where a mechanism is attached that allows a user to pull on the tether. The distal end 74 of the tether 72 is attached to the distal intersection 42 of the cutting unit 44. Pulling on the tether 72 causes the distal intersection 42 to retract, causing the cutting unit 44 to assume the second configuration, as seen in FIG. 17.

[0080] As used in this disclosure, the terms "substantially" or "generally" mean a complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is "substantially" or "generally" sealed means that the object is either completely sealed or nearly completely sealed. Exactly how much deviation from absolute completeness is allowed may in some cases depend on the particular context. However, generally, the proximity to completeness will be the degree of completion such that the overall result is the same as if absolute and complete perfection had been achieved. Similarly, the expressions "substantially" or "generally" are applicable when used in a negative sense to mean that an action, characteristic, property, state, structure, item, result, etc. is completely or nearly completely absent. For example, an element, combination, embodiment, or composition that "substantially does not contain" or "generally does not contain" a certain component or element may actually still contain that item, generally to the extent that there is no measurable effect.

[0081] Any reference to "one embodiment" or "an embodiment" used in this disclosure means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Although the phrase "in one embodiment" appears throughout this specification, it does not necessarily refer to the same embodiment each time.

[0082] As used herein, the terms "comprise", "comprising", "includes", "has", "having", or other variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, article, or apparatus consisting of a list of elements is not necessarily limited to only those elements, but may include other elements not expressly listed or elements inherent to that process, method, article, or apparatus. Also, unless expressly stated otherwise, "or" means an inclusive "or" and not an exclusive "or". For example, the condition A or B is satisfied in any of the following cases: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), or both A and B are true (or exist).

[0083] Also, for the purpose of describing the elements and components of the embodiments of this disclosure, the use of "a" or "an" is adopted. This is merely for convenience to give a general meaning to the description. This specification should be read to include one or at least one unless it is obvious otherwise, and the singular form also includes the plural form.

[0084] Although the present invention has been described from the perspective of specific embodiments and applications, those skilled in the art can, in light of this teaching, create additional embodiments and modifications without departing from the spirit of the invention described in the claims or exceeding the scope of the invention described in the claims. Therefore, it is understood that the drawings and the specification in the present disclosure are presented as examples for facilitating the understanding of the present invention and should not be construed as limiting its scope.

Claims

1. 1. A system for modifying a native valve leaflet, comprising: A catheter, a tissue engaging mechanism in the form of a retention mechanism advanceable from the catheter and configured to secure the cardiac valve leaflets; a cutting element advanceable from the catheter and movable relative to the tissue engaging mechanism; The system wherein the cutting element is configured to deliver RF energy and includes a wire that self-expands into a looped or swept-wing shape.

2. The system of claim 1 , wherein the wire is made of a shape memory metal and is heat treated to assume the looped shape or the swept-wing shape.

3. The system of claim 1 , wherein the cutting element includes an exposed element for energizing and cutting the valve leaflets.

4. The system of claim 1 , wherein the cutting element includes a sharp edge for mechanically cutting the valve leaflets.

5. The system of claim 1 , wherein the tissue engaging feature comprises a barb.

6. The system of claim 1 , further comprising a tether configured to change the configuration of the cutting element between a first configuration and an expanded second configuration.

7. The system of claim 6 , wherein the tether is attached to a distal crossover of the cutting element.

8. The system of claim 1 , further comprising a connecting element connecting a push rod and the cutting element.

9. The system of claim 1 , wherein the tissue engagement feature is configured to pierce the cardiac valve leaflets.

10. The system of claim 1 , wherein the tissue engaging feature comprises a hypotube deployable for passage of a guidewire therethrough.

11. The system of claim 1 , wherein the tissue engagement mechanism is configured to secure the heart valve leaflets during both systole and diastole.

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