US20080140188A1 - Devices, systems, and methods for reshaping a heart valve annulus - Google Patents

Abstract

Devices, systems, and methods employ a heart implant structure that is sized and configured to be positioned in a left atrium above the plane of a native mitral heart valve annulus to affect mitral heart valve function. The implant structure includes a portion sized and configured to engage a wall of the left atrium above the plane of the native mitral valve annulus and to extend across the left atrium along a minor axis of the annulus.

Description

RELATED APPLICATIONS
• This application is a divisional of co-pending U.S. patent application Ser. No. 10/846,850, filed May 14, 2004, which is a continuation-in-part of U.S. patent application Ser. No. 10/677,104, filed Oct. 1, 2003, and entitled “Devices, Systems, and Methods for Reshaping a Heart Valve Annulus,” which claims the benefit of U.S. patent application Ser. No. 09/666,617, filed Sep. 20, 2000 and entitled “Heart Valve Annulus Device and Methods of Using Same,” which is incorporated herein by reference. This application also claims the benefit of Patent Cooperation Treaty Application Serial No. PCT/US 02/31376, filed Oct. 1, 2002 and entitled “Systems and Devices for Heart Valve Treatments,” which claimed the benefit of U.S. Provisional Patent Application Ser. No. 60/326,590, filed Oct. 1, 2001, which are incorporated herein by reference. This application also claims the benefit of U.S. Provisional Application Ser. No. 60/429,444, filed Nov. 26, 2002, and entitled “Heart Valve Remodeling Devices;” U.S. Provisional Patent Application Ser. No. 60/429,709, filed Nov. 26, 2002, and entitled “Neo-Leaflet Medical Devices;” and U.S. Provisional Patent Application Ser. No. 60/429,462, filed Nov. 26, 2002, and entitled “Heart Valve Leaflet Retaining Devices,” which are each incorporated herein by reference.
FIELD OF THE INVENTION
• The invention is directed to devices, systems, and methods for improving the function of a heart valve, e.g., in the treatment of mitral valve regurgitation.
BACKGROUND OF THE INVENTIONI. The Anatomy of a Healthy Heart
• The heart (seeFIG. 1) is slightly larger than a clenched fist. It is a double (left and right side), self-adjusting muscular pump, the parts of which work in unison to propel blood to all parts of the body. The right side of the heart receives poorly oxygenated (“venous”) blood from the body from the superior vena cava and inferior vena cava and pumps it through the pulmonary artery to the lungs for oxygenation. The left side receives well-oxygenation (“arterial”) blood from the lungs through the pulmonary veins and pumps it into the aorta for distribution to the body.
• The heart has four chambers, two on each side—the right and left atria, and the right and left ventricles. The atria are the blood-receiving chambers, which pump blood into the ventricles. A wall composed of membranous and muscular parts, called the interatrial septum, separates the right and left atria. The ventricles are the blood-discharging chambers. A wall composed of membranous and muscular parts, called the interventricular septum separates the right and left ventricles.
• The synchronous pumping actions of the left and right sides of the heart constitute the cardiac cycle. The cycle begins with a period of ventricular relaxation, called ventricular diastole. The cycle ends with a period of ventricular contraction, called ventricular systole.
• The heart has four valves (seeFIGS. 2 and 3) that ensure that blood does not flow in the wrong direction during the cardiac cycle; that is, to ensure that the blood does not back flow from the ventricles into the corresponding atria, or back flow from the arteries into the corresponding ventricles. The valve between the left atrium and the left ventricle is the mitral valve. The valve between the right atrium and the right ventricle is the tricuspid valve. The pulmonary valve is at the opening of the pulmonary artery. The aortic valve is at the opening of the aorta.
• At the beginning of ventricular diastole (i.e., ventricular filling) (seeFIG. 2), the aortic and pulmonary valves are closed to prevent back flow from the arteries into the ventricles. Shortly thereafter, the tricuspid and mitral valves open (asFIG. 2 shows), to allow flow from the atria into the corresponding ventricles. Shortly after ventricular systole (i.e., ventricular emptying) begins, the tricuspid and mitral valves close (see FIG.3)—to prevent back flow from the ventricles into the corresponding atria—and the aortic and pulmonary valves open—to permit discharge of blood into the arteries from the corresponding ventricles.
• The opening and closing of heart valves occur primarily as a result of pressure differences. For example, the opening and closing of the mitral valve occurs as a result of the pressure differences between the left atrium and the left ventricle. During ventricular diastole, when ventricles are relaxed, the venous return of blood from the pulmonary veins into the left atrium causes the pressure in the atrium to exceed that in the ventricle. As a result, the mitral valve opens, allowing blood to enter the ventricle. As the ventricle contracts during ventricular systole, the intraventricular pressure rises above the pressure in the atrium and pushes the mitral valve shut.
• The mitral and tricuspid valves are defined by fibrous rings of collagen, each called an annulus, which forms a part of the fibrous skeleton of the heart. The annulus provides attachments for the two cusps or leaflets of the mitral valve (called the anterior and posterior cusps) and the three cusps or leaflets of the tricuspid valve. The leaflets receive chordae tendineae from more than one papillary muscle. In a healthy heart, these muscles and their tendinous cords support the mitral and tricuspid valves, allowing the leaflets to resist the high pressure developed during contractions (pumping) of the left and right ventricles.
• In a healthy heart, the chordae tendineae become taut, preventing the leaflets from being forced into the left or right atria and everted. Prolapse is a term used to describe this condition. This is normally prevented by contraction of the papillary muscles within the ventricle, which are connected to the mitral valve leaflets by the chordae tendineae. Contraction of the papillary muscles is simultaneous with the contraction of the ventricle and serves to keep healthy valve leaflets tightly shut at peak contraction pressures exerted by the ventricle.
II. Characteristics and Causes of Mitral Valve Dysfunction
• In a healthy heart (seeFIG. 4), the dimensions of the mitral valve annulus create an anatomic shape and tension such that the leaflets coapt, forming a tight junction, at peak contraction pressures. Where the leaflets coapt at the opposing medial and lateral sides of the annulus are called the leaflet commissures, and are designated inFIG. 4 and in other Figures as CM (denoting the medial commissure) and CL (denoting the lateral commissure).
• Valve malfunction can result from the chordae tendineae (the chords) becoming stretched, and in some cases tearing. When a chord tears, the result is a leaflet that flails. Also, a normally structured valve may not function properly because of an enlargement of or shape change in the valve annulus. This condition is referred to as a dilation of the annulus and generally results from heart muscle failure. In addition, the valve may be defective at birth or because of an acquired disease.
• Regardless of the cause (seeFIG. 5), mitral valve dysfunction can occur when the leaflets do not coapt at peak contraction pressures. AsFIG. 5 shows, the coaptation line of the two leaflets is not tight at ventricular systole. As a result, an undesired back flow of blood from the left ventricle into the left atrium can occur. This condition is called regurgitation.
• In some cases (seeFIG. 6), the leaflets do not form a tight coaptation junction because the dimensions of the mitral valve annulus, measured along the major axis from commissure to commissure—CM to CL—and/or measured along the minor axis anterior to posterior—A to P—change. The changed dimensions no longer create the anatomic shape and tension in which the leaflets coapt at peak contraction pressures.
• Comparing a healthy annulus inFIG. 4 to an unhealthy annulus inFIG. 6, the unhealthy annulus is dilated and, in particular, the anterior-to-posterior distance along the minor axis is increased. As a result, the shape and tension defined by the annulus becomes less oval (seeFIG. 4) and more round (seeFIG. 6). This condition is called dilation. When the annulus is dilated, the shape and tension conducive for coaptation at peak contraction pressures progressively deteriorate. Instead, at peak contraction pressures, the leaflets do not coapt completely, and a gap forms between the leaflets. During ventricular systole, regurgitation can occur through this gap. It is believed that the ratio between the commissure-to-commissure distance along the major axis and anterior-to-posterior distance along the minor axis bears a relationship to the effectiveness of leaflet coaptation. If the anterior-to-posterior distance along the minor axis increases, the ratio changes, and when the ratio reaches a certain value, regurgitation or the likelihood of regurgitation is indicated.
• As a result of regurgitation, “extra” blood back flows into the left atrium. During subsequent ventricular diastole (when the heart relaxes), this “extra” blood returns to the left ventricle, creating a volume overload, i.e., too much blood in the left ventricle. During subsequent ventricular systole (when the heart contracts), there is more blood in the ventricle than expected. This means that: (1) the heart must pump harder to move the extra blood; (2) too little blood may move from the heart to the rest of the body; and (3) over time, the left ventricle may begin to stretch and enlarge to accommodate the larger volume of blood, and the left ventricle may become weaker.
• Although mild cases of mitral valve regurgitation result in few problems, more severe and chronic cases eventually weaken the heart and can result in heart failure. Mitral valve regurgitation can be an acute or chronic condition. It is sometimes called mitral insufficiency.
III. Prior Treatment Modalities
• In the treatment of mitral valve regurgitation, diuretics and/or vasodilators can be used to help reduce the amount of blood flowing back into the left atrium. An intra-aortic balloon counterpulsation device is used if the condition is not stabilized with medications. For chronic or acute mitral valve regurgitation, surgery to repair or replace the mitral valve is often necessary.
• To date, invasive, open heart surgical approaches have been used to repair mitral valve dysfunction. During these surgical repair procedures, efforts are made to cinch or resect portions and/or fix in position large portions of the dilated annulus. During these surgical repair procedures, the annulus can be reshaped with annular or peri-annular rings or similar ring-like devices. The repair devices are typically secured to the annulus and surrounding tissue with suture-based fixation. The repair devices extend over the top and over much or all of the circumference of the annulus and leaflet surfaces.
• A physician may decide to replace an unhealthy mitral valve rather than repair it. Invasive, open heart surgical approaches are used to replace the natural valve with either a mechanical valve or biological tissue (bioprosthetic) taken from pigs, cows, or horses.
• The need remains for simple, cost-effective, and less invasive devices, systems, and methods for treating dysfunction of a heart valve, e.g., in the treatment of mitral valve regurgitation.
SUMMARY OF THE INVENTION
• The invention provides devices, systems, and methods that employ an implant sized and configured to attach, at least in part, in, on, or near the annulus of a dysfunctional heart valve. In use, the implant extends either across the minor axis of the annulus to shorten the minor axis, or across the major axis of the annulus to lengthen the major axis, or both. The implant restores to the heart valve annulus and leaflets a more functional anatomic shape and tension. The more functional anatomic shape and tension are conducive to coaptation of the leaflets, which, in turn, reduces retrograde flow or regurgitation.
• One aspect of the invention provides devices, systems, and methods that include a heart implant structure that is sized and configured to be positioned in a left atrium above the plane of a native mitral heart valve annulus to affect mitral heart valve function. The implant structure includes a portion sized and configured to engage a wall of the left atrium above the plane of the native mitral valve annulus and to extend across the left atrium along a minor axis of the annulus.
• Another aspect of the invention provides devices, systems, and methods that include an implant structure sized and configured to be positioned in a left atrium above the plane of a native mitral heart valve annulus to affect mitral heart valve function. The implant structure includes a first portion sized and configured to engage a wall of the left atrium above the plane of the native mitral valve annulus and to extend across the left atrium along a minor axis of the annulus. The implant structure also includes a second portion sized and configured to extend through a septum to rest in a right atrium.
• In one embodiment, the implant structure is sized and configured so that, in use, the implant structure changes the shape of the native mitral heart valve annulus.
• In one embodiment, the implant structure inwardly displaces tissue to shorten the minor axis.
• Other features and advantages of the invention shall be apparent based upon the accompanying description, drawings, and claims.
DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective, anterior anatomic view of the interior of a healthy heart.
• FIG. 2 is a superior anatomic view of the interior of a healthy heart, with the atria removed, showing the condition of the heart valves during ventricular diastole.
• FIG. 3 is a superior anatomic view of the interior of a healthy heart, with the atria removed, showing the condition of the heart valves during ventricular systole.
• FIG. 4 is a superior anatomic view of a healthy mitral valve during ventricular systole, showing the leaflets properly coapting.
• FIG. 5 is a superior anatomic view of the interior of a heart, with the atria removed, showing the condition of the heart valves during ventricular systole, and further showing a dysfunctional mitral valve in which the leaflets are not properly coapting, causing regurgitation.
• FIG. 6 is a superior anatomic view of a disfunctional mitral valve during ventricular systole, showing that the leaflets are not properly coapting, causing regurgitation.
• FIGS. 7A and 7B are side perspective views of implants sized and configured to rest at or near a heart valve annulus and apply a direct mechanical force along the minor axis of the annulus to inwardly displace tissue toward the center of the annulus, the implant shown inFIG. 7A being configured to extend significantly above the plane of the valve, and the implant shown inFIG. 7B being configured to extend a short distance above the plane of the valve.
• FIG. 8 is a lateral perspective view of the implant shown inFIG. 7A deployed at or near the mitral valve annulus in the left atrium.
• FIG. 9 is a superior view of the implant and heart shown inFIG. 8.
• FIGS. 10A. 10B, and10C are perspective anterior views of the intravascular deployment of a catheter from the right atrium across the septum into the left atrium for the purpose of implanting an implant of the type shown inFIG. 7A.
• FIGS. 11A,11B, and11C are lateral perspective views of the sequential deployment of the implant shown inFIG. 7A from the catheter shown inFIGS. 10A,10B, and10C in the left atrium, with a balloon being shown inFIG. 11C inflated to place the implant into tension across the minor axis of the mitral valve.
• FIG. 12 is a side perspective view of an alternative embodiment of an implant sized and configured to rest at or near a heart valve annulus and apply a direct mechanical force along the minor axis of the annulus to inwardly displace tissue toward the center of the annulus, the implant shown inFIG. 12 including bell-shaped protrusions that can be grasped to aid in the positioning and/or tensioning of the implant.
• FIG. 13 is a lateral perspective view of the implant shown inFIG. 12 deployed at or near the mitral valve annulus in the left atrium, with one of the bell-shaped protrusions extending through and anchored to the septum in the right atrium.
• FIG. 14 is a side view of an alternative embodiment of an implant sized and configured to rest at or near a heart valve annulus and apply a direct mechanical force along the minor axis of the annulus to inwardly displace tissue toward the center of the annulus, the implant shown inFIG. 14 having an anterior component that is sized and configured to pass through the septum and project into the right atrium.
• FIG. 15 is a lateral perspective view of a pair of the implants shown inFIG. 14 deployed at or near the mitral valve annulus in the left atrium, with the anterior component extending through and anchored to the septem in the right atrium.
• FIG. 16 is a superior view of the implants and the heart shown inFIG. 15.
• FIGS. 17A and 17B are lateral side views of the deployment of one of the implants shown inFIGS. 15 and 16 from the right atrium and through the septum into the left atrium.
• FIGS. 18A and 18B are superior views of a mitral valve annulus having different embodiments of magnetic force systems implanted at or near the annulus, to generate a magnetic field that attract tissue regions of the annulus toward one another, the magnetic force systems being arranged to shorten the minor axis of the annulus.
• FIG. 18C is an anterior side view of the magnetic force systems shown inFIGS. 18A and 18B.
• FIGS. 19A and 19B are superior views of a mitral valve annulus with other alternative embodiments of implanted magnetic force systems of the types shown inFIGS. 18A,18B, and18C implanted at or near the annulus, to generate a magnetic field that attract tissue regions of the annulus toward one another to shorten the minor axis of the annulus.
• FIG. 20 is a superior view of a mitral valve annulus with an alternative embodiment of an implanted magnetic force system implanted at or near the annulus along one side of the annulus, to generate a magnetic field that attract tissue regions along that side of the annulus toward one another.
• FIG. 21 is a representative embodiment of button-shaped magnetic elements that can be used to create the magnetic force systems shown inFIGS. 18A,18B,18C,19A,19B, and20.
• FIG. 22 is a side section view of a button-shaped magnetic element taken generally along line22-22 is FIG.21.
• FIGS. 23A and 23B are a representative embodiment of a button-shaped magnetic element that can be used to create the magnetic force systems shown inFIGS. 18A,18B,18C,19A,19B, and20, the magnetic element including a leaflet retaining appendage that overlays a native valve leaflet,FIG. 23A being a side perspective view andFIG. 23B being a side section view of the magnetic element and appendage.
• FIG. 24 is a superior view of a mitral valve with the magnetic elements shown inFIGS. 23A and 23B implanted along opposite anterior and posterior sides of the annulus.
• FIG. 25 is a superior view of a heart showing the presence of a magnetic force system having one magnetic element implanted within the coronary sinus above the posterior annulus of the mitral valve and a second magnetic element implanted on the septum in the right atrium close to the anterior annulus of the mitral valve, to create between them a force of magnetic attraction that shortens the minor axis of the mitral valve.
• FIG. 26 is a lateral perspective view of the left atrium showing the implantation at or near a mitral valve of an implant along the major axis and an implant along the minor axis, forming a combined implant system that can concurrently lengthen the major axis and shorten the minor axis.
• FIG. 27 is a superior view of the combined implant system and heart shown inFIG. 26.
• FIG. 28 is a side view of a representative embodiment of an implant that can be implanted along the major axis of a valve annulus in association with the system shown inFIGS. 26 and 27, the implant being sized to apply a direct mechanical force along the major axis of the annulus to lengthen the major axis.
• FIG. 29 is a side perspective view of an alternative embodiment of an implant that can be implanted along the major axis of a valve annulus in association with the system shown inFIGS. 26 and 27.
• FIG. 30 is a lateral perspective view showing the implant shown inFIG. 29 implanted along the major axis of a mitral valve within the left atrium.
• FIG. 31 is a side perspective view of a multiple function implant that is sized and configured to rest about a valve annulus to concurrently reshape the valve annulus along both major and minor axes, the implant inFIG. 31 having barbs that can be placed into contact with tissue at or near the annulus.
• FIG. 32 is a lateral perspective view showing the implant shown inFIG. 31 implanted about a mitral valve within the left atrium.
• FIG. 33 is a side perspective view of an alternative embodiment of a multiple function implant that is sized and configured to rest about a valve annulus to concurrently reshape the valve annulus along both major and minor axes, the implant inFIG. 35 having inwardly folded barbs that can be outwardly folded by expansion of the implant into contact with tissue at or near the annulus.
• FIGS. 34,35, and36 are superior views of the outwardly folding of the barbs of the implant shown inFIG. 33 in response to the inflation of a balloon.
• FIG. 37 is a lateral perspective view showing the implant shown inFIG. 33 implanted about a mitral valve within the left atrium.
• FIGS. 38A,38B, and38C are lateral perspective views of the sequential deployment of the implant shown inFIG. 28 from the catheter shown inFIGS. 10A,10B, and10C, the implant being deployed in compression across the major axis of the mitral valve in the left atrium.
• FIG. 39 is a side perspective view of an alternative embodiment of an implant that can be implanted along the major axis of a valve annulus in association with the system shown inFIGS. 26 and 27, the implant being sized and configured to rest at or near a heart valve annulus and apply a direct mechanical force along the major axis of the annulus to outwardly displace tissue away from the center of the annulus, the implant shown inFIG. 39 including bell-shaped protrusions that can be grasped to aid in the positioning and/or placement of the implant into compression.
• FIG. 40 is a lateral perspective view of the implant shown inFIG. 39 deployed at or near the mitral valve annulus in the left atrium, with one of the bell-shaped protrusions extending through and anchored to the septum in the right atrium.
• FIG. 41 is a lateral perspective view of a combined implant system of the type shown inFIG. 26 that can concurrently lengthen the major axis and shorten the minor axis, the system including a major axis implant and a minor axis implant both of which include a bell-shaped protrusion that extends through and is anchored to the septum in the right atrium.
• FIG. 42 is a side perspective view of an alternative embodiment of a multiple function implant that is sized and configured to rest about a valve annulus to concurrently reshape the valve annulus along both major and minor axes, the implant inFIG. 42 having a major axis component that comprises an elastic member of the type shown inFIG. 28 and a minor axis component that comprises a magnetic force system of the type shown inFIG. 18A.
• FIG. 43 is a superior section view of a heart showing the installation of a point loaded annuloplasty system about the mitral valve annulus.
• FIGS. 44A,44B, and44C are perspective views of representative embodiments of clip components that accommodate passage of an elastic frame to create the point loaded annuloplasty system shown inFIG. 43.
• FIG. 45 is a superior section view of a heart showing the installation of an alternative embodiment of a point loaded annuloplasty system about the mitral valve annulus, the system shown inFIG. 45 having a point attachment in the right atrium across the septum.
• FIG. 46 is a perspective view of an implant sized and configured to perform commissural annuloplasty at or near the mitral valve in the left atrium, the implant having elastic jaws that squeeze the annulus together at the commissures to promote leaflet coaptation.
• FIG. 47 is a lateral perspective view of the left atrium, showing the placement of the implant shown inFIG. 46 in the mitral valve to perform commissural annuloplasty.
• FIGS. 48A and 48B are enlarged superior views of the elastic jaws that the implant shown inFIG. 46 includes to create pulling forces at a commissure,FIG. 48A showing the jaws spread apart to engage tissue at or near a commissure, andFIG. 48B showing the jaw in an in-tension condition to squeeze the annulus together at the commissure to promote leaflet coaptation.
• FIG. 49 shows an anterior perspective view of a mitral valve in which a structural variation of the implant shown inFIG. 46 has been implanted, the structural variation having elastic jaws that have been lengthened and shaped to follow the medial and lateral contours of the annulus to be placed into tension across the minor axis of the annulus to provide a mechanical force that shortens the minor axis in the manner shown inFIG. 9.
• FIG. 50 shows a perspective view of a variation of the implant shown inFIG. 46, which includes a ring-like structure that carries magnetic elements, to provide a magnetic force that shortens the minor axis in the manner shown inFIG. 18A.
DETAILED DESCRIPTION
• Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention, which may be embodied in other specific structure. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.
I. Implants for Direct Shortening of the Minor Axis of a Heart Valve Annulus
• A. Intra-Atrial Implants
• 1. Structure
• FIGS. 7A and 7B show embodiments ofimplants10 sized and configured to rest at or near a heart valve annulus. InFIGS. 8 and 9, the embodiment of theimplant10 ofFIG. 7A is shown resting in a mitral valve. In this arrangement (asFIGS. 8 and 9 show), theimplant10 extends along the minor axis (i.e., across the valve annulus in an anterior-to-posterior direction).
• AsFIGS. 8 and 9 show, theimplant10 is sized and shaped so that, in use, it applies a direct mechanical force along the minor axis of the annulus. The direct mechanical force serves to inwardly displace tissue (i.e., to displace tissue toward the center of the annulus) to reshape the annulus. In the illustrated embodiment (i.e., the mitral valve), the mechanical force serves to shorten the minor axis of the annulus. In doing so, theimplant10 can also reactively reshape the annulus along its major axis and/or reactively reshape other surrounding anatomic structures.
• It should be appreciated that, when situated in other valve structures, the axes affected may not be the “major” and “minor” axes, due to the surrounding anatomy. It should also be appreciated that, in order to be therapeutic, the implant may only need to reshape the annulus during a portion of the heart cycle, such as during ventricular systolic contraction. For example, the implant may be sized to produce small or negligible displacement of the annulus to restore or enhance inward movement of the annulus during ventricular diastolic contraction.
• The mechanical force applied by theimplant10 across the minor axis can restore to the heart valve annulus and leaflets a more normal anatomic shape and tension (seeFIGS. 8 and 9). The more normal anatomic shape and tension are conducive to coaptation of the leaflets during ventricular systole, which, in turn, reduces regurgitation.
• In its most basic form, theimplant10 is made—e.g., by bending, shaping, joining, machining, molding, or extrusion—from a biocompatible metallic or polymer material, or a metallic or polymer material that is suitably coated, impregnated, or otherwise treated with a material to impart biocompatibility, or a combination of such materials. The material is also desirably radio-opaque or incorporates radio-opaque features to facilitate fluoroscopic visualization.
• AsFIGS. 7A and 7B show, theimplant10 includes a pair ofstruts12 joined by anintermediate rail14. AsFIG. 8 shows, thestruts12 are sized and configured to engage tissue at either an infra-annular position (i.e., engaging the fibrous body of the annulus) or a supra-annular position (i.e., engaging atrial tissue above or near the annulus). Therail14 spans thestruts12. The rail14 (like the struts12) can take various shapes and have various cross-sectional geometries. The rail14 (and/or the struts12) can have, e.g., a generally curvilinear (i.e., round or oval) cross section, or a generally rectilinear cross section (i.e., square or rectangular), or combinations thereof. In the embodiment shown inFIGS. 7A and 8, therail14 of theimplant10 is configured to extend significantly above the plane of the valve toward the dome of the left atrium. In the embodiment shown inFIG. 7B, therail14 of theimplant10 is configured to not extend significantly above the plane of the valve, but extend only enough to avoid interference with the valve leaflets.
• Thestruts12 each include one ormore fixation elements16. A givenfixation element16 is sized and configured to take purchase in tissue in either the infra-annular or supra-annular position. Thefixation element16 desirably relies at least partly on the valve annulus and/or neighboring anatomic structures to anchor and fix the position of the implant and resist its migration out of the annulus.
• InFIG. 7, thefixation element16 comprises an array of barbs that penetrate tissue.FIGS. 12 and 13 (which will be described in greater detail later) show another representative embodiment for afixation element16, which comprises an array of tines that may contain secondary barbs in a direction that facilitates griping the tissue. Other types and forms oftissue fixation elements16 can be used, e.g., pads with or without tissue penetrating members, and/or roughened surfaces and/or tissue in-growth promoting materials, such as polyester fabric. Anyfixation element16 may, if desired, be combined with suture, an adhesive, or like material to further secure the implant.
• Being free of an appendage that extends beneath the annulus, adjustment of implant position after or during implantation is facilitated. Theimplant10 also presents less chance of trauma or damage to tissue and anatomic structures beneath the annulus.
• As shown inFIGS. 7 to 9, theimplant10 is desirably “elastic.” Therail14 is sized and configured to possess a normal, unloaded, shape or condition (shown inFIG. 7). In this condition, therail14 is not in compression or tension, and thestruts12 are spaced apart closer than the anterior-to-posterior dimension of the minor axis of the targeted heart valve annulus. The material of theimplant10 is selected to possess a desired spring constant. The spring constant imparts to therail14 the ability to be elastically spread apart and placed in tension out of its normal, unloaded condition, in response to external stretching forces applied at the struts.
• When thestruts12 are stretched apart and anchored in tissue at or near the annulus (seeFIGS. 8 and 9), therail14 assumes an elastically loaded, in-tension condition. When in its elastically loaded, in-tension condition, therail14 exerts, through thestruts12 andfixation element16, opposing pulling forces on tissues at or near the annulus. These forces are shown by arrows marked PF inFIGS. 8 and 9. The pulling forces inwardly displace tissue and shorten the annulus along its minor axis. The pulling forces can also reshape the major axis and/or surrounding anatomic structures. In this way, theimplant10 can reshape the valve annulus toward a shape more conducive to leaflet coaptation.
• An elastic implant as described can be made, e.g., from superelastic alloy, like Nitinol material. In this arrangement, the implant can also be elastically straightened and/or folded to fit within a catheter or sheath during deployment, and will regain a preferred shape upon deployment.
• The spring constant of theimplant10 may be selected to be greater than the spring constant of adjoining tissue. Alternatively, the spring constant of theimplant10 may be selected to approximate the spring constant of adjoining tissue, thereby providing compliance to allow theimplant10 to adapt to tissue morphology during use. The spring constant of theimplant10 may vary along the length of therail14, so that some portions of therail14 are stiffer or more compliant than other portions of therail14.
• 2. Implantation
• Theimplant10 as just described and shown in eitherFIG. 7A or7B lends itself to implantation in a heart valve annulus in various ways. Theimplant10 can be implanted, e.g., in an open heart surgical procedure. Alternatively, theimplant10 can be implanted using catheter-based technology via a peripheral venous access site, such as in the femoral or jugular vein or femoral artery, under image guidance. Alternatively, theimplant10 can be implanted using thoracoscopic means through the chest, or by means of other surgical access through the right atrium, also under image guidance. Image guidance includes but is not limited to fluoroscopy, ultrasound, magnetic resonance, computed tomography, or combinations thereof.
• FIGS. 10 and 11 show a representative embodiment of the deployment of anelastic implant10 of the type shown inFIGS. 7A,8, and9 by a percutaneous, catheter-based procedure, under image guidance.
• Percutaneous vascular access is achieved by conventional methods into the femoral or jugular vein. AsFIG. 10A shows, under image guidance, acatheter52 is steered through the vasculature into the right atrium. Aneedle cannula54 carried on the distal end of the catheter is deployed to pierce the septum between the right and left atrium. AsFIG. 10B shows, aguide wire56 is advanced trans-septally through theneedle catheter52 into the left atrium. Thefirst catheter52 is withdrawn (asFIG. 10C shows), and under image guidance, animplant delivery catheter58 is advanced over theguide wire56 into the left atrium into proximity with the mitral valve. Alternatively, theimplant delivery catheter58 can be deployed trans-septally by means of surgical access through the right atrium.
• Theimplant delivery catheter58 carries asheath60 at its distal end (seeFIG. 10C). Theimplant10 is constrained in a collapsed, straightened condition within the sheath. Thesheath60 is sized and configured to be withdrawn (e.g., by sliding it proximally), to progressively free theimplant10. Progressively freed from thesheath60, theelastic implant10 will expand and take shape. Alternatively, a flexible push rod in thecatheter58 can be used to expel theimplant10 from thesheath60, with the same result.
• Desirably, thestruts12 are folded within thesheath60 to reduce the collapsed profile and facilitate the expansion of theimplant10 once free of thesheath60. AsFIG. 11A shows, under image guidance, thestrut12 on the posterior end of theimplant10 is first freed from thesheath60. Theposterior strut12 is manipulated to place thefixation element16 into tissue in or near the posterior annulus. AsFIG. 11B shows, thedelivery catheter58 maintains force on theposterior strut12, as thesheath60 is further withdrawn, as the catheter tracks across the minor axis of the annulus in a posterior-to-anterior direction. Thedelivery catheter58 may be sized and configured to have the column strength sufficient to maintain force on the posterior strut. Progressively freed from thesheath60, theelastic implant10 takes shape (seeFIG. 11C), until theanterior strut12 unfolds. Therail14 can be placed into tension, e.g., using a balloon B and/or catheter-deployed grasping instruments, to seat thefixation element16 of theanterior strut12 in tissue at or near the anterior annulus. Once seated, thestrut12 is released by thecatheter58.
• In an alternative embodiment (seeFIG. 12), theimplant10 includes bell-shapedprotrusions20 and22 formed, respectively, along anterior and posterior portions of therail14. AsFIG. 13 shows, theanterior protrusion20 is sized and configured to, when implanted, extend through the septum and project into the right atrium. There, theanterior protrusion20 is exposed for manipulation by a suitable grasping instrument deployed in the right atrium. For example, the grasping instrument can take hold of theprotrusion20 in the right atrium to facilitate placement of therail14 in tension within the left atrium. Theposterior protrusion22 within the left atrium can also be grasped by an instrument in the left atrium, to aid in positioning and/or for tensioning the rail.
• AsFIG. 13 shows, barbed stays24 braced against the septum can be crimped to theanterior protrusion20, to help maintain a desired degree of tension on therail14 in the left atrium.
• Furthermore, the projection of theanterior protrusion20 into the right atrium facilitates repositioning and/or retrieval of theimplant10 from the right atrium, when desired.
• B. Trans-Septal Implants
• 1. Structure
• FIG. 14 shows another embodiment of animplant26, which is sized and configured to apply a mechanical force along the minor axis of a heart valve, or to otherwise stabilize tissue adjacent a heart valve annulus, and, in particular, a mitral heart valve annulus, asFIGS. 15 and 16 show. In the illustrated embodiment, and as described in connection with theimplant10 shown inFIG. 7, the mechanical force that is applied by theimplant26 inFIGS. 15 and 16 (shown by arrows) serves to inwardly displace tissue (i.e., to displace tissue toward the center of the annulus) (seeFIGS. 15 and 16), to shorten the minor axis and reshape the valve. As previously described, the mechanical force directly applied by theimplant26 across the minor axis can also reactively reshape the major axis of the annulus as well as reshape other surrounding anatomic structures. Theimplant26 can restore the heart valve annulus and leaflets to a more normal anatomic shape and tension conducive to coaptation of the leaflets during ventricular systole, which, in turn, reduces regurgitation. It should be appreciated, however, the presence of theimplant26 may serve to stabilize tissue adjacent the heart valve annulus, without affecting the length of the minor axis.
• As shown inFIG. 14, theimplant26 is made—e.g., by bending, shaping, joining, machining, molding, or extrusion—from a biocompatible metallic or polymer material, or a metallic or polymer material that is suitably coated, impregnated, or otherwise treated with a material to impart biocompatibility, or a combination of such materials. The material is also desirably radio-opaque to facilitate fluoroscopic visualization.
• As shown inFIG. 14, theimplant26 includes a pair ofstruts28 and30 joined by anintermediate rail32. The rail32 (like thestruts28 and30) can take various shapes and have various cross-sectional geometries. The rail32 (and/or thestruts28 and30) can have, e.g., a generally curvilinear (i.e., round or oval) cross-section, or a generally rectilinear cross section (i.e., square or rectangular), or combinations thereof.
• Thestruts28 and30 at one or both ends of therail32 may include afixation element34 to enhance fixation in tissue. Varioustissue fixation elements34 can be used, e.g., tissue penetrating barbs (as shown), pads with roughened surfaces or tissue in-growth promoting materials, such as polyester fabric. Anyfixation element34 may, if desired, be combined with suture, an adhesive, or like material to further secure the implant.
• As shown inFIGS. 15 and 16 show, thefixation element34 on theposterior strut30 is sized and configured to engage tissue at either an infra-annular position (i.e., engaging the fibrous body of the annulus) or a supra-annular position (i.e., engaging atrial tissue) above or near the posterior annulus within the left atrium.
• Thefixation element34 onanterior strut28 is sized and configured to pass through the septum and project into the right atrium. There, thefixation element34 itself can engage tissue in the septum. Alternatively, asFIGS. 15 and 16 show, thefixation element34 can include ananchor button36. Theanchor button36 captures theanterior strut28 and holds theanterior strut28 against the septum in the right atrium.
• 2. Implantation
• Theimplant26 can be deployed within acatheter52 from the right atrium into the left atrium, in the same manner shown inFIGS. 10A,10B, and10C. Thefixation element34 on theposterior strut30 is positioned in engagement with tissue in either an infra-annular or supra-annular location the posterior annulus (asFIG. 17A shows), and theanterior strut28 is lead through the septum (asFIG. 17B shows).
• AsFIG. 17B shows, pulling on theanterior strut28 within the right atrium (i.e., through the septum) exerts a pulling force on tissue at or near the posterior annulus (shown by an arrow inFIG. 17B). The pulling force draws the posterior annulus inwardly toward the anterior annulus, thereby shortening the annulus along its minor axis. As previously described, the pulling forces can also reactively reshape the annulus along its major axis, as well as reshape surrounding anatomic structures. In this way, the implant reshapes the valve annulus toward a shape more conducive to leaflet coaptation, just as theimplant10 previously described.
• As shown in the embodiment illustrated inFIGS. 15 and 16, at least two of theimplants26 are desirably used concurrently, to distribute pulling forces along medial and lateral sides of the minor axis. In this arrangement, thefixation elements34 on the posterior struts30 take purchase in tissue within the left atrium in spaced-apart locations above or near or in the posterior annulus. Thefixation elements34 on the anterior struts28 jointly pass through the septum. Pulling on the anterior struts28 from within the right atrium draws the posterior annulus toward the anterior annulus, thereby shortening the annulus across its minor axis. The anterior struts28 can be pulled individually or concurrently to achieve the reshaping desired.
• In this arrangement, asFIG. 16 best shows, oneimplant26 is shaped to direct force outward toward the septum wall of the left atrium, while theother implant26 is shaped to direct force outward toward the lateral wall of the left atrium. The resulting forces are uniformly distributed along the posterior annulus.
• Once the desired degree of pulling force is established, the anterior struts28 can be jointly fixed against the septum by theanchor button36. As before described, thefixation elements34 themselves can apply the holding force, without use of theanchor button36.
• C. Magnetic Force Systems
• 1. Structure
• FIGS.18A/B/C and19A/B show various embodiments of amagnetic force system62 that, in use, shortens an axis of a heart valve using one or more implantedmagnetic elements64. The implantedmagnetic elements64 generate magnetic field forces that attract tissue regions of the annulus toward one another.
• As shown in FIGS.18A/B/C to19A/B, the tissue regions comprise the posterior and anterior edges of a mitral valve annulus. The magnetic field forces draw the tissue regions closer together across the minor axis of the annulus. The minor axis of the annulus is thereby shortened. As already described, shortening of the minor axis can reshape the valve, as well as reshape other surrounding anatomic structures, to restore the heart valve annulus and leaflets to a more normal anatomic shape and tension conducive to coaptation of the leaflets during ventricular systole, which, in turn, reduces regurgitation.
• InFIGS. 18A and 18B, themagnetic elements64 comprise two or more permanent magnets66. Permanent magnets66 can comprise, e.g., alloys of Neodymium-Iron-Boron (NdFeB), alloys of Aluminum-Nickel-Cobalt (AlNiCo), and Samarium Cobalt (SmCo). A permanent magnet66 generates an external magnetic field. AsFIGS. 18A and 18B shows, twopermanent magnets66A and66B are affixed on or above the annulus in the left atrium, with opposite magnetic poles facing each other (North-South or South-North). Poles of opposite polarity attract each other with a magnetic force. The force of magnetic attraction depends on the strength of the magnets and the distance between them.
• InFIGS. 18A and 18B, twopermanent magnets66A and66B of opposite polarity are affixed, respectively, on or above the anterior and posterior regions of the annulus, aligned generally across the minor axis of the annulus. The force of magnetic attraction (shown by arrows) draws the posterior annulus and the anterior annulus toward one another, shortening the minor axis (seeFIG. 18C also).
• InFIG. 18B, at least one additionalpermanent magnet66C is provided on or above the posterior annulus on one or both sides of the magnet aligned on the minor axis. The additionalpermanent magnet66C has a pole facing the adjacentminor axis magnet66A that is like the pole of the adjacent minor axis magnet. Poles of like polarity repel each other with a magnetic force. The force of magnetic repulsion pushes the additionalpermanent magnet66C and the adjacentminor axis magnet66A apart, keeping the twomagnets66A and66C on the posterior annulus apart and stretching tissue between themagnets66A and66C. At the same time, due to the presence of an additional permanent magnet, the force of magnetic attraction between thepermanent magnets66A and66C on the posterior annulus and theanterior annulus66B is amplified, further enhancing the force that draws the posterior annulus and the anterior annulus toward one another, shortening the minor axis.
• InFIGS. 19A and 19B, apermanent magnet66D is affixed on or above either the anterior annulus or the posterior annulus generally aligned with the minor axis. InFIGS. 19A and 19B, thepermanent magnet66D is shown affixed on or above the anterior annulus. On the opposite annulus (which, inFIGS. 19A and 19B, comprises the posterior annulus), an array of softferromagnetic materials68, e.g. Iron (Fe), is affixed.
• Softmagnetic materials68 are attracted by apermanent magnet66D. The force of magnetic attraction draws the posterior annulus and the anterior annulus toward one another, shortening the minor axis. The force of attraction can be strengthened (seeFIG. 19B) by affixing an additionalpermanent magnet66E on or above the anterior annulus adjacent the minor axispermanent magnet66D. As described with respect to the embodiment shown inFIG. 18B, the additionalpermanent magnet66E has a pole facing the adjacent minor axis magnet that is like the pole of the adjacentminor axis magnet66D. The force of magnetic repulsion pushes the additional permanent magnet and minor axis magnet apart, keeping the two magnets on the anterior annulus spaced apart and stretching tissue between the twomagnets66D and66E.
• As shown inFIG. 20, two or morepermanent magnets66F and66G having opposite magnetic poles can be affixed on or above given regions of the annulus (here, the anterior annulus), without companion, oppositely spaced magnets. The force of magnetic attraction draws the permanent magnets together, stretching the tissue along the circumference of the posterior annulus. The magnetic force field reshaping occasioned in this arrangement shortens the minor axis, reshaping the annulus.
• AsFIGS. 21 and 22 show, the permanent magnets66 and/or softferromagnetic materials68 can be machined, laser cut, chemically etched, or EDM manufactured intopackets70 of various shapes. Thepackets70 are desirably encased or packaged in an inert, insulation material, such as gold. The packets include one ormore fixation elements72, which anchor thepackets70 in tissue on or above the targeted valve annulus.
• InFIGS. 21 and 22, thepackets70 are button-shaped, and thefixation elements72 comprise barbs that penetrate tissue. Other shapes and configuration can, of course, be used.
• In FIGS.23A/B, thepacket70 is button-shaped and further includes aleaflet retaining appendage76. When anchored into tissue on or above an annulus (see FIG.24), theleaflet retaining appendage76 overlays at least a portion of one or more native valve leaflets. Theleaflet retaining appendage76 resists leaflet eversion and/or prolapse. In this way, a system of magnetic implants not only reshapes the valve annulus along the minor axis, but also prevents or reduces retrograde flow and regurgitation. Theleaflet retaining appendage76 does not interfere with the opening of and blood flow through the leaflets during antegrade flow.
• FIG. 25 shows another embodiment of a magnetic force system78 that, in use, shortens an axis of a heart valve using one or more implantedmagnets80 and82. InFIG. 25, themagnets80 and82 are not anchored on or above the annulus within the heart chamber occupied by the heart valve. Instead, themagnets80 and82 are placed outside the heart chamber to generate magnetic field forces that attract tissue regions of the annulus toward one another.
• In the embodiment shown inFIG. 25, the heart valve comprises the mitral valve in the left atrium. Apermanent magnet80 is implanted either in the coronary sinus near the posterior annulus or on the septum in the right atrium close to the anterior annulus. InFIG. 25, thepermanent magnet80 is shown implanted in the coronary sinus. A secondmagnetic element82 is implanted in the other location—here, on the septum in the right atrium close to the anterior annulus. The secondmagnetic element82 can comprise a permanent magnet having a polarity opposite to the polarity of the first permanent magnet, or it can comprise a soft ferromagnetic material. The force of magnetic attraction between thepermanent magnet80 and the secondmagnetic element82 draws the posterior annulus and the anterior annulus toward one another, shortening the minor axis.
• Magnetic force systems62 or78 that shorten an axis of a heart valve can be deployed during an open surgical or thoracoscopic procedure. Alternatively, catheter-based approaches may also be used.
II. Implant Systems for Directly Lengthening the Major Annulus Axis while Directly Shortening the Minor Axis
• Any implant of the types just described can be used alone, to provide direct shortening along the minor axis of the annulus, which can also provide reactive lengthening of the annulus along its major axis.
• AsFIGS. 26 and 27 show, a givenminor axis implant84 may also be used in combination with amajor axis implant86, forming a combinedimplant system88. In thesystem88, themajor axis implant86 provides direct lengthening along the major axis of the annulus. In thesystem88, the active lengthening of the major axis (by the major axis implant86) is accompanied by the active shortening of the minor axis (by the minor axis implant84). Use of themajor axis implant86 complements theminor axis implant84, enhancing the reactive lengthening of the major axis occasioned by use of theminor axis implant84.
• Of course, themajor axis implant86 can be used alone. When used alone, themajor axis implant86 can reactively shorten in the minor axis, as well as correspondingly reshape other surrounding anatomic structures.
• Themajor axis implant86 can be sized and configured to achieve other objectives. Themajor axis implant86 can, for example, be sized and configured to shorten the major axis. Alternatively, themajor axis implant86 can be sized and configured to merely stabilize tissue adjacent the heart valve annulus, without attendant lengthening or shortening of the major axis. As before stated, amajor axis implant86 of these alternative sizes and configurations can be used alone or in combination with a minor axis implant.
• A. Elastic Implant Systems
• 1. Single Function Major Axis Implant Structures
• In one representative embodiment (seeFIGS. 26 and 27), e.g., for reshaping a mitral valve annulus, themajor axis implant86 is sized and configured as a single function component to rest along the major axis of the annulus above and/or along the valve annulus, alone or in combination with a single functionminor axis implant84. Themajor axis implant86 can be of the type described in copending U.S. patent application Ser. No. 10/677,104, filed Oct. 1, 2003, and entitled “Devices, Systems, and Methods for Reshaping a Heart Valve Annulus,” which is incorporated herein by reference.
• As described in the above-identified application, themajor axis implant86 is desirably made—e.g., by bending, shaping, joining, machining, molding, or extrusion—from a biocompatible, super-elastic metallic material. As shown inFIG. 28, themajor axis implant86 includes a pair ofstruts90 joined by anintermediate rail92. AsFIGS. 27 and 28 show, thestruts90 of themajor axis implant86 are sized and configured to rest in, at, or near the leaflet commissures. The superelastic material of theimplant86 is selected to possess a desired spring constant, which imparts to therail92 the ability to be elastically compressed into an elastically loaded condition resting in engagement with tissue in, at, or near the leaflet commissures. When in its elastically loaded, compressed condition, therail92 exerts opposing forces to the tissues in, at, or near the commissures through thestruts90, tending to outwardly displace tissue and stretch the annulus along its major axis.
• FIGS. 29 and 30 show another representative example of a single functionmajor axis implant86. Themajor axis implant86 can be used alone (asFIGS. 29 and 30 show) or in association with a single functionminor axis implant84 to form asystem88 of the type shown inFIGS. 26 and 27. Theimplant86 includes tworails92 forming a closed rail structure. Therails92 are supported bylegs134. Thelegs134 are generally spaced 180° apart. In use (seeFIG. 30), theimplant86 resides in the atrium above the mitral valve. The depending base of eachleg134 carries afixation element136. Thefixation element136 takes purchase in atrial tissue above and near to the commissures along the major axis of the annulus. The spring force of thelegs134 and rails92 apply a spreading force that stretches tissue along the major axis. The high rails92 protects against spreading of the leaflets.
• In the illustrated embodiment, thefixation element136 comprises a pad of barbs that penetrate atrial tissue above the annulus. However, other types of tissue engaging mechanisms can be used, e.g., roughened surfaces or tissue in-growth promoting materials. Placingnumerous fixation elements136 onlegs134 that engage tissue above the annulus makes it possible to reduce the force applied per unit of tissue area. Anyfixation element146 may, if desired, be combined with suture, an adhesive, or like material to further secure the implant.
• Major axis implants86 like that shown inFIGS. 29 and 30 can be located without the need to identify the exact position of the commissures. Adjustment of implant position after or during implantation is also facilitated, as there is no need to remove a strut from a commissure.Implants86 like that shown inFIGS. 29 and 30 also present less chance of trauma or damage to tissue and anatomic structures beneath the annulus.
• 2. Multiple Function Major and Minor Axis Implant Structures
• In another representative embodiment (seeFIG. 31), e.g., for reshaping a mitral valve annulus, amulti-function implant138 can be sized and configured to rest about the annulus (asFIG. 32 shows) and function to reshape both major and minor axes.
• Themulti-function implant138 is desirably made—e.g., by bending, shaping, joining, machining, molding, or extrusion—from a biocompatible, super-elastic metallic material. As shown inFIG. 31, theimplant138 includes a pair ofstruts140 joined by a pair of oppositely spacedrails142 and144, forming a ring-like structure. Therails142 and144, of course, can take various shapes.
• AsFIG. 32 shows, thestruts140 of theimplant138 are sized and configured to rest in, at, or near the leaflet commissures. The superelastic material of theimplant138 is selected to possess a desired spring constant, which imparts to therails142 and144 the ability to be elastically compressed into an elastically loaded condition resting in engagement with tissue in, at, or near the leaflet commissures. When in the elastically loaded, compressed condition, therails142 and144 exert opposing forces to the tissues in, at, or near the commissures through thestruts140, tending to outwardly displace tissue and providing the function of stretching the annulus along its major axis. Alternatively, thestruts140 can comprise the legs and fixation elements shown inFIGS. 29 and 30, or other forms of tissue fixation mechanisms, to accommodate purchase in atrial tissue above the annulus, to perform the same function.
• AsFIG. 31 shows, therails142 and144 includefixation elements146, which, in the illustrated embodiment, take the form of tissue penetrating barbs. Thefixation elements146 on therails142 and144 are sized and configured to take purchase in tissue in either annular, infra-annular or supra-annular tissue adjacent to, respectively, the anterior annulus and the posterior annulus (asFIG. 32 shows). The superelastic material of theimplant138 is selected to possess a desired spring constant, which imparts to therails142 and144 the ability to be elastically stretched and placed into tension when resting in engagement with tissue adjacent the anterior annulus and posterior annulus. When in the elastically loaded, in-tension condition, therails142 and144 exert opposing pulling forces on tissue at or near the annulus. This provides the function of shortening the annulus along its minor axis. Therails142 and144 can be expanded apart, e.g., by use of aballoon148 placed between therails142 and144 and inflated, placing thefixation elements146 into contact with tissue. Collapsing the balloon allows the implant to assume its desired shape with the tissue attached.
• Other types and forms oftissue fixation elements146 can be used. For example, as shown inFIG. 33, thetissue fixation elements146 can comprise barbs that are deployed in an inwardly folded condition. Thebarbs146 can be outwardly folded when therails142 and144 are expanded apart, e.g., by use of aballoon148 placed between therails142 and144 and inflated (seeFIG. 34). Upon further inflation of the balloon148 (seeFIGS. 35 and 36), thebarbs146 are driven into in either infra-annular or supra-annular tissue adjacent to the anterior annulus and the posterior annulus (asFIG. 37 shows). Theballoon148 also places therails142 and144 into tension, to perform their intended function of shortening the minor axis of the annulus.
• In other embodiments, thetissue fixation elements146 can take the form of pads with or without tissue penetrating members, and/or roughened surfaces and/or tissue in-growth promoting materials, such as polyester fabric. Anyfixation element146 may, if desired, be combined with suture, an adhesive, or like material to further secure theimplant138.
• 3. Implantation
• Any of thesingle function implants86 ormultiple function implants138 can be elastically straightened and/or folded to fit within a catheter or sheath for deployment, as generally shown inFIG. 10C. Alternatively, thesingle function implants86 ormultiple function implants138 can be deployed during an open surgical or thoracoscopic procedure.
• For example, with respect to the single function,major axis implant86, access into the left atrium through the septum from the right atrium can be accomplished as shown inFIGS. 10A,10B, and10C. Theimplant delivery catheter58 carries themajor axis implant86 in asheath60 at its distal end (seeFIG. 38A), in a collapsed, straightened condition. AsFIG. 38A shows, under image guidance, thestrut90 on the leading end of themajor axis implant86 is freed from thesheath60 and seated retrograde in the medial commissure of the valve annulus. Thesheath60 is withdrawn in line with the coaptation line in a lateral direction along the coaptation line. Progressively freed from thesheath60, themajor axis implant86 shapes and seats (asFIGS. 38B and 38C show), until the trailingstrut90 unfolds and seats within the lateral commissure. Theimplant86 can also be positioned or repositioned under image guidance within the left atrium using a catheter-deployed grasping instrument.
• In an alternative embodiment (seeFIG. 39), themajor axis implant86 can include bell-shapedprotrusions94 and96 formed along medial and lateral portions of therail92. AsFIG. 40 shows, themedial protrusion94 is sized and configured to extend through the septum and project into the right atrium. There, themedial protrusion94 is exposed for engagement by a grasping instrument deployed in the right atrium. The grasping instrument in the right atrium can take hold of theprotrusion94 to facilitate placement of therail92 in compression within the left atrium. Barbed stays98 can be crimped to themedial protrusion94 to help maintaining compression on therail92. The medial grasping site, projecting into the right atrium, also facilitates repositioning and/or retrieval of themajor axis implant86. Thelateral protrusion96 can likewise be grasped by an instrument in the left atrium for placing therail92 in compression.
• As shown inFIG. 41, both theminor axis implant84 and themajor axis implant86 can include graspingprotrusions100 and102 that jointly project through the septum into the right atrium. Bothprotrusions100 and102 can be manipulated to place theminor axis implant84 into tension and to place themajor axis implant86 into compression, as previously described, to achieve the desired reshaping of the annulus.
• B. Elastic Implant-Magnetic Force Field Systems
• Other types of systems that concurrently accomplish direct major and minor reshaping are possible. For example,FIG. 42 shows a representative embodiment of asystem104 that includes anelastic component106, to provide direct reshaping along one axis of a valve annulus, and a magneticforce field component108, to provide direct reshaping along another axis of the valve annulus.
• In the embodiment shown inFIG. 42, the valve to be reshaped is the mitral valve in the left atrium. In this arrangement, theelastic component106 comprises an elastic major axis implant of the type already described (e.g., as shown inFIG. 30 or39), which is sized and configured to rest along the major axis of the annulus above and/or along the valve annulus. As previously described, the elasticmajor axis implant106 stretches the annulus along the major axis.
• In this arrangement, the magneticforce field component108 comprisesmagnetic elements132 of the type previously described (e.g., as shown inFIGS. 21A to 21E). Themagnetic elements132 are located in a spaced-apart relationship across the minor axis on or above the anterior annulus and the posterior annulus. Themagnetic elements132 can comprise two permanent magnets of opposite polarity, or one permanent magnet and one soft ferromagnetic material. In the illustrated embodiment, themagnetic elements132 are stabilized at opposite ends of ayoke110 coupled to the elasticmajor axis implant106 near one of its struts. Themagnetic elements132 are implanted in tissue on or above the annulus. The force of magnetic attraction between themagnet components132 draws the posterior annulus and the anterior annulus toward one another, shortening the minor axis.
• Theyoke110 supporting themagnetic elements132 may possess a spring constant. Placing theyoke110 into tension at the time themagnetic elements132 are implanted on or above the annulus provides an auxiliary mechanical force, to augment the magnetic force serving to shorten the minor axis.
III. Annuloplasty Systems
• A. Point Loading
• FIG. 43 shows a point loadedannuloplasty system112 for reshaping a heart valve annulus. Thesystem112 applies a mechanical force about the perimeter of the heart valve annulus. The mechanical force pulls on the annulus to restore a generally oval shape conducive to leaflet coaptation. For purpose of illustration,FIG. 43 shows the heart valve annulus as comprising the mitral valve in the left atrium.
• InFIG. 43, thesystem112 creates the mechanical force by circumferentially linking adjacent sites on or above the annulus with a biocompatibleelastic frame114. In the illustrated embodiment, theframe114 comprises an elastic material, such as Selastic™ material. Theframe114 links the sites by threading through a network offasteners116 that are inserted into tissue on or above the annulus.FIGS. 44A to 44C show representative embodiments of thefasteners116, which includeclip components118 to accommodate passage of theframe114 andbarbs120 that secure theclip components118 to tissue. Theelastic frame114 is in tension within the network offasteners116. The tension applied by theframe114 pulls tissue in or along the annulus together, thereby tightening the annulus to restore a non-dilated shape.
• An alternative embodiment of a pointloading annuloplasty system122 is shown inFIG. 45. InFIG. 45, as inFIG. 43, anelastic frame114 is placed into tension through a network offasteners116 that are inserted into tissue on or above the annulus. InFIG. 43, all of thefasteners116 were located in or along the annulus. InFIG. 45, onefastener116′ is located in the right atrium outside the left atrium. Thefastener116′ engages the septum. In this arrangement, theframe114 passes through the septum, pulling laterally on the septum toward the left atrium to reshape tissue along the anterior annulus.
• B. Commissural Annuloplasty
• FIG. 46 shows animplant124 for performing commissural annuloplasty. AsFIG. 47 shows, theimplant124 is sized and configured, in use, to rest along the major axis of a heart valve annulus above and/or along the valve annulus. In the illustrated embodiment (seeFIG. 47), theimplant124 rests along the major axis of a mitral valve annulus in the left atrium.
• Theimplant124 is desirably made—e.g., by bending, shaping, joining, machining, molding, or extrusion—from a biocompatible metallic or plastic material. As shown inFIG. 39, theimplant124 includes a pair ofstruts126 joined by anintermediate rail128.
• AsFIG. 47 shows, thestruts126 are sized and configured to rest in either an infra-annular or a supra-annular position at or near the annulus adjacent the medial and lateral leaflet commissures.
• Theimplant124 includes ajaw130 that is appended to eachstrut126. Thejaws130 are made from an elastic material. Eachjaw130 is sized and configured to possess a normal, unloaded, shape or condition (shown inFIG. 46). In this condition, thejaw130 is not in compression or tension. The material of eachjaw130 is selected to possess a desired spring constant. The spring constant imparts to eachjaw130 the ability to be elastically spread apart (seeFIG. 48A) and placed in tension out of its normal, unloaded condition, in response to external stretching forces applied to thejaws130.
• When thejaws130 are anchored in tissue in a stretched apart condition at or near the commissures (seeFIGS. 48A and 48B), thejaws130 assumes an elastically loaded, in-tension condition. When in this elastically loaded, in-tension condition, thejaws130 exert opposing pulling forces on tissues at or near the commissures. These forces are shown by arrows inFIG. 48B. The pulling forces inwardly displace tissue at the commissures, squeezing the annulus together at the commissures to promote leaflet coaptation.
• Theimplant124 can rest as shown inFIG. 47 without being in compression and/or tension, thereby itself applying no pushing or pulling force upon tissue along either, the major or minor axes of the annulus. Alternatively, theimplant124 can be made of an elastic material. This imparts to therail128 the ability to be compressed into an elastically loaded condition resting in engagement with tissue in, at, or near the leaflet commissures. When in this condition, therail124 can exert opposing forces to the tissues in, at, or near the commissures through thestruts126, tending to outwardly displace tissue and stretch the annulus along its major axis.
• Furthermore, as shown inFIG. 49, one or both of thejaws130 of theimplant124 can be lengthened and shaped to follow the medial and lateral contours of the annulus, terminating in an oppositely facing relationship on the anterior annulus and posterior annulus, similar to theyoke110 shown inFIG. 42. In this arrangement, thejaws130 possess a spring constant. Placing thejaws130 in tension across the minor axis of the annulus (asFIG. 49 shows) at the time of implantation provides a mechanical force that shortens the minor axis, in the manner previously described. Thejaws130 can be further lengthened and shaped to form a full ring-like structure.
• As shown inFIG. 50, theimplant124 can be used in association with a magneticforce field component132 of the type previously described (e.g., as shown inFIGS. 21A to 21E). Themagnetic components132 are located in a spaced-apart relationship across the minor axis on or above the anterior annulus and the posterior annulus. Themagnetic components132 can comprise two permanent magnets of opposite polarity, or one permanent magnet and one soft ferromagnetic material. In the illustrated embodiment, Themagnetic components132 are implanted in tissue on or above the annulus. The force of magnetic attraction between themagnet components132 draws the posterior annulus and the anterior annulus toward one another, shortening the minor axis.
• Based upon the foregoing, it is apparent that implant systems can be provided that affect direct shortening of the minor axis, and/or direct lengthening of the major axis, alone or in combination using various mechanical and/or magnetic means. It is also apparent that shaping of a heart valve annulus can be accomplished by mechanical and/or magnetic force applied circumferentially about the annulus, and/or by reshaping tissue at the commissures, alone or in combination with mechanical and/or magnetic forces that reshape the annulus along its major axis and/or minor axis.
• While the new devices and methods have been more specifically described in the context of the treatment of a mitral heart valve, it should be understood that other heart valve types can be treated in the same or equivalent fashion. By way of example, and not by limitation, the present systems and methods could be used to prevent or reduce retrograde flow in any heart valve annulus, including the tricuspid valve, the pulmonary valve, or the aortic valve. In addition, other embodiments and uses of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. The specification and examples should be considered exemplary and merely descriptive of key technical; features and principles, and are not meant to be limiting. The true scope and spirit of the invention are defined by the following claims. As will be easily understood by those of ordinary skill in the art, variations and modifications of each of the disclosed embodiments can be easily made within the scope of this invention as defined by the following claims.

Claims (12)

1. A method comprising

providing a heart implant sized and configured to be positioned in a left atrium above the plane of a native mitral heart valve annulus to affect mitral heart valve function, the implant including a first portion sized and configured to engage a wall of the left atrium above the plane of the native mitral valve annulus and to extend across the left atrium along a minor axis of the annulus, the implant including a second portion sized and configured to extend through a septum to rest in a right atrium,

establishing an intravascular access path that extends from the right atrium through the septum and into the left atrium,

deploying the implant through the intravascular path into the left atrium, and

positioning the implant with the first portion engaging a wall of the left atrium above the plane of the native mitral valve annulus and extending across the left atrium along a minor axis of the annulus and with the second portion extending through the septum to rest in the right atrium, such that the implant affects mitral heart valve function.

2. A method according toclaim 1

wherein the implant is positioned so that the implant changes the shape of the native mitral heart valve annulus.

3. A method according toclaim 1

wherein the implant inwardly displaces tissue to shorten the minor axis.

4. A heart implant comprising

an implant structure sized and configured to be positioned in a left atrium above the plane of a native mitral heart valve annulus to affect mitral heart valve function, the implant structure including a first portion sized and configured to engage a wall of the left atrium above the plane of the native mitral valve annulus and to extend across the left atrium along a minor axis of the annulus, the implant structure including a second portion sized and configured to extend through a septum to rest in a right atrium.

5. A heart implant according toclaim 4

wherein the implant structure is sized and configured so that, in use, the implant structure changes the shape of the native mitral heart valve annulus.

6. A heart implant according toclaim 4

wherein the implant structure inwardly displaces tissue to shorten the minor axis.

7. A method comprising

providing a heart implant sized and configured to be positioned in a left atrium above the plane of a native mitral heart valve annulus to affect mitral heart valve function, the implant including a portion sized and configured to engage a wall of the left atrium above the plane of the native mitral valve annulus and to extend across the left atrium along a minor axis of the annulus,

establishing an intravascular access path that extends from the right atrium through the septum and into the left atrium,

deploying the implant through the intravascular path into the left atrium, and

positioning the implant with the portion engaging a wall of the left atrium above the plane of the native mitral valve annulus and extending across the left atrium along a minor axis of the annulus to affect mitral heart valve function.

8. A method according toclaim 7

wherein the implant is positioned so that the implant changes the shape of the native mitral heart valve annulus.

9. A method according toclaim 7

wherein the implant inwardly displaces tissue to shorten the minor axis.

10. A heart implant comprising

an implant structure sized and configured to be positioned in a left atrium above the plane of a native mitral heart valve annulus to affect mitral heart valve function, the implant structure including a portion sized and configured to engage a wall of the left atrium above the plane of the native mitral valve annulus and to extend across the left atrium along a minor axis of the annulus.

11. A heart implant according toclaim 10

wherein the implant structure is sized and configured so that, in use, the implant structure changes the shape of the native mitral heart valve annulus.

12. A heart implant according toclaim 10

wherein the implant structure inwardly displaces tissue to shorten the minor axis.

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