US20100049315A1 - Annuloplasty with enhanced anchoring to the annulus based on tissue healing - Google Patents

Abstract

Methods, delivery systems and engaging apparatuses for the placement and treatment of an insufficient or stenotic cardiac valve, such as the mitral valve are disclosed. One such method is based on a two step procedure, where during the first step the engaging apparatus is brought to the valve annulus using a delivery system which permits continued normal blood flow. In some preferred embodiments, this is implemented with a balloon and other preferred embodiments it is implemented using a multi-pronged structure that is collapsible like an umbrella frame. The second step is performed after the engaging apparatus has been integrated into the annular wall by natural processes of tissue healing and remodeling. In the second step the engaging apparatus is tightened leading to tightening of the valve annulus and correction of existing valvular insufficiency. Optionally, an artificial valve may be anchored to the engaging apparatus during the same or subsequent procedure to correct either valvular insufficiency or stenosis.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• This application is a divisional of U.S. application Ser. No. 11/837,077, filed Aug. 10, 2007, which claims the benefit of U.S. provisional application No. 60/822,113, filed Aug. 11, 2006. Both of those applications are incorporated herein by reference.
BACKGROUND
• In the recent past, many advances have been made to reduce the invasiveness of cardiac surgery. In an attempt to avoid open, stopped-heart procedures, which may be accompanied by high patient morbidity and mortality, many devices and methods have been developed for performing surgery on a heart through smaller incisions, operating on a beating heart, and finally, in the past years, performing cardiac procedures via transvascular access. Significant technological advances have been made in various types of cardiac procedures, such as cardiac ablation techniques for treating atrial fibrillation, stenting procedures for atherosclerosis, and valve repair procedures. More specifically, much progress has been made on treating conditions such as mitral valve regurgitation. In implementing many minimally invasive cardiac surgery techniques, especially beating-heart techniques, one of the most significant challenges is positioning a treatment device and once positioned, to effectively deploy and fix a given device or treatment into or on the surface of the target cardiac tissue.
• Traditional treatment of heart valve stenosis or regurgitation, such as mitral or tricuspid regurgitation, typically involves an open-heart surgical procedure to replace or repair the valve. Valve repair procedures typically involve annuloplasty, a set of techniques designed to restore the valve annulus shape and strengthen the annulus. Conventional annuloplasty surgery generally requires a thoracotomy, and sometimes a median sternotomy. These open heart procedures involve placing the patient on a cardiopulmonary bypass machine for sustained periods so that the patient's heart and lungs can be artificially stopped during the procedure. Finally, valve repair and replacement procedures are technically challenging and require a relatively large incision through the wall of the heart to access the valve.
• Due to the highly invasive nature of open heart valve repair or replacement, high risk patients are usually not candidates for these procedures and thus are destined to functional deterioration and cardiac enlargement. Often, such patients have no feasible alternative treatments for their heart valve conditions.
• In order to try and solve this problem, a number of devices and methods for repairing cardiac valves in a less invasive manner have been described. Some devices offer heart valve repair through minimally invasive incisions or intravascularly, while others attempt to improve open heart surgical procedures on beating hearts, stopped hearts or both. Difficulties in performing minimally invasive intra-cardiac surgery include positioning a minimally invasive treatment device in a desired location for performing a procedure and effectively placing and fixing a device into or on the surface of the target cardiac tissue. In heart valve repair procedures, for example, it is often essential for a physician to fix a device to valve annulus tissue. Annular tissue tends to be more fibrous than surrounding muscular or valve leaflet tissue, thus providing a more suitable location for securing such a device. In the past, various types of anchors and anchoring techniques have been developed in order to fix treatment devices to the annular tissue. This is an important stage in all annuloplasty procedures and especially in procedures for treating mitral or tricuspid valve regurgitation.
• Devices and methods that address these difficulties are described in U.S. Patent Application Nos. 60/445,890, 60/459,735, 60/462,502, 60/524,622, Ser. No. 10/461,043, Ser. No. 10/656,797 and Ser. No. 10/741,130. For example, these references describe devices and methods for exposing, stabilizing and/or performing procedure on a heart valve annulus, such as a mitral valve annulus. Many of these methods and devices have shown preliminary promise, however a highly safe and effective method and engaging apparatus for performing cardiac valve annuloplasty has, until now, been lacking.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 shows the location of the mitral annulus in a cross-section of the heart.
• FIG. 2 shows a first approach for positioning a first embodiment of an engaging apparatus at the annulus.
• FIG. 3 shows a cross section of the embodiment shown inFIG. 2.
• FIG. 4 shows an embodiment of a delivery system in which a multi-pronged device is used to place the engaging apparatus at the annulus.
• FIG. 5 shows a close up of the end of theFIG. 4 embodiment.
• FIG. 6 is a detailed view of the first embodiment of the engaging apparatus.
• FIG. 7 shows a detailed view of another embodiment of the engaging apparatus.
• FIG. 8 shows the engaging apparatus ofFIG. 7 in location at the mitral annulus immediately after being positioned and anchored to the tissue.
• FIG. 9 shows the engaging apparatus ofFIG. 7 after being left in place for sufficient time for tissue healing and remodeling to occur.
• FIG. 10 shows another embodiment of an engaging apparatus that contains an integral anchoring delivery system.
• FIG. 11 shows theFIG. 10 embodiment with an artificial valve anchored to the engaging apparatus.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• FIG. 1 shows the location of themitral annulus2 in a cross-section of the heart. The method and engaging apparatus of the current delivery system are used to facilitate transvascular, minimally invasive and other “less invasive” surgical procedures, by facilitating the placing and fixing of atreatment engaging apparatus6 at a treatment site. As used herein, “less invasive” means any procedure that is less invasive than traditional, large-incision, open surgical procedures. Generally, any procedure in which a goal is to minimize or reduce invasiveness to the patient may be considered less invasive. Although the methods described herein are developed for use in minimally invasive procedures, they may be applied to performing or enhancing any suitable procedure, including traditional open heart surgery. The present application describes methods and apparatuses for performing heart valve repair or replacement procedures, and more specifically heart valve annuloplasty procedures such as mitral valve annuloplasty to treat mitral regurgitation and mitral valve replacement to treat mitral stenosis. In other embodiments, the devices and methods may be used to enhance a laparoscopic or other endoscopic procedure on any part of the body, such as the bladder, stomach, gastroesophageal junction, vasculature, gall bladder, or the like. Therefore, although the following description typically focuses onmitral valve8 andother heart valve9 repair, such description should not be interpreted to limit the scope of the invention.
• FIG. 2 shows a cross-section of the heart, with a full view of one embodiment of aballoon delivery system4 and a full view of anengaging apparatus6. Theballoon delivery system4 can be used for placement of theengaging apparatus6 at theannulus2. Initially, the balloon is routed to the proper position in its deflated state (not shown) using any suitable route or method (e.g., an endoscopic technique), and then inflated. At this point, the system will resembleFIG. 2, in which theballoon4 is shown in its inflated state, positioned at themitral valve8. Theengaging apparatus6 is located around theballoon4, and the inflation brings theengaging apparatus6 into proximity of theannular tissue2 and presses them towards each other. Theengaging apparatus6 initially surrounds theballoon4 and anchors to theannular tissue2 upon inflation of theballoon4.
• FIG. 3 depicts the same items asFIG. 2 except that the delivery system is shown in cross section. The balloon is shown with acentral channel10 andflexible leaflets12 seen within its lumen. Theseleaflets12 act as a temporary replacement valve in order to allow normal heart function during the insertion procedure. In some embodiments, valve repair or replacement may be implemented using a hollow,inflatable balloon4 with integralflexible valve leaflets12 within its lumen which act as a temporary replacement for the natural valve upon inflation, while maintaining adequate flow through from theatrium1 to theventricle3 throughout the procedure viachannel10. Because of thechannel10, blood can flow through the system even when theballoon6 is inflated, which facilitates installation of the device into a beating heart.
• Upon deflation of the balloon, theengaging apparatus6 will detach from theballoon4 and remain attached to theannulus2 with enough anchoring force to withstand normal cardiac contraction, flow and valve movement. Attachment to the annulus can be aided by using appropriate anchors, hooks, barbs, etc. Alternatively, theengaging apparatus6 can hold itself in place by exerting a centripetal pressure on the annulus, generated by the springiness of the engaging apparatus.
• In some embodiments (not shown), theengaging apparatus6 may be contained within a hidden circumferential pocket surrounding theballoon4 and will engage theannular tissue2 only upon release from this pocket. The release of theengaging apparatus6 from theballoon4 may be performed by releasing a slip-knot like suture from theballoon4 or any other suitable alternative approach. In these embodiments, conventional balloon and balloon inflation technology may be used, similar to those used in other annuloplasty procedures (e.g., conventional balloon procedures for widening a stenotic valve).
• FIG. 4 shows a cross-section of the heart, a full view of the first embodiment of anengaging apparatus6, and a full view of the second embodiment of a delivery system. This delivery system uses amulti-pronged device14 that is preferably collapsible (similar to an umbrella frame, a truncated wire whisk, etc). to place the engagingapparatus6 at theannulus2. The methods and engaging apparatus of the delivery system, however, may be used in any suitable procedure, both cardiac and non-cardiac. For example, they may be used in procedures to repair anyheart valve9, to replace anyheart valve9, to repair an atrial-septal11 defect, to access and possibly perform a valve repair from (or through) the coronary sinus.
• FIG. 5 shows a detail view of themulti-pronged delivery system14 shown inFIG. 4. In some embodiments, valve repair may be implemented using adelivery device14 which can be extended from the tip of acatheter16 to allow for the correct positioning of theengaging apparatus6 at the annulus. Themulti-pronged placement device14 can be introduced into the left atrium1 (shown inFIG. 4) during on-pump or off-pump procedures through the wall of the atrium or through the intra-atrial septum, with thecatheter16 introduced by intravascular or minimal invasive approach. Placement and tightening may be performed on a beating heart because blood can flow through the spaces between the prongs. Access to the beating heart may be accomplished by any available technique, including intravascular, trans-thoracic, and the like. Intravascular access to a heart valve may be achieved using any suitable route or method.
• For example, to perform a procedure on a mitral valve8 acatheter16 may be advanced through a femoral artery, to the aorta, and into the left ventricle of the heart, to contact a length of the mitral valve. After it is so positioned, thedevice14 is expanded so as to press theengaging apparatus6 against the annulus. The expansion of thedelivery system14 may be implemented using any suitable technique such as withdrawal of a sheath that permits the prongs to spring out to their natural state. Alternatively, access may be gained through the venous delivery system, to a central vein, into the right atrium of the heart, and across the inter-atrial septum to the left side of the heart to contact a length of the mitral valve. In alternative embodiments, thecatheter device16 may access the coronary sinus and a valve procedure may be performed directly from the sinus. Furthermore, in addition to beating heart access, methods of the present delivery system may be used for intravascular stopped heart access as well as stopped heart open chest procedures. Any suitable intravascular or other access method may be substituted.
• FIG. 6 shows a detailed view of the first embodiment of the engaging apparatus. This embodiment uses ahelical spring18 that has been formed to be substantially arc-shaped preferably subtending an arc of at least 180°, and more preferably at least 270°, with awire20 within it for subsequent tightening. The spring geometry allows for changes in ring diameter, and creates a channel for the tightening wire. It also allows for tissue healing into the spaces in thespring22, thereby bonding the engaging apparatus to the annulus wall by embedding the engaging apparatus within the annulus wall. Some time after the initial placement, a second procedure for tightening theengaging apparatus6 is preferably implemented.
• Tightening of the engaging apparatus may be accomplished, for example, by retracting awire20 left within theengaging apparatus6 during its placement at the annulus using a minimally invasive approach. However, any alternative method or device for the tightening of a structure at the annulus may be used. This includes, but is not limited to, different types of steerable catheter tips16 (as shown inFIG. 4) catheters allowing for direct manipulation of objects at the tip, catheters allowing for visualization of the annulus, and catheters which deliver energy at the area of interest (ultrasound, heat, radiofrequency fields, etc.). Non-invasive techniques for tightening theengaging apparatus6 may also be used, including but not limited to magnetic manipulation through the chest wall, radiofrequency energy delivery through the chest wall and ultrasound energy transmitted through the chest wall.
• Theengaging apparatus6 may be made of Stainless Steel, Nitinol, Elgiloy or Titanium; however any material with the necessary strength, flexibility and biocompatibility to withstand cardiac pressures may be used. A suitable diameter for the arc is between about 25 and about 60 mm. A suitable diameter for the helix is between about 1 and about 3 mm, and a suitable pitch for the helix is between about 1 and about 3 mm.
• In some embodiments, theengaging apparatus6 may be constructed of a spring likering18 with or without a central cavity for atightening wire20. This spring likering18 may be configured to facilitate the growth of annular tissue into theengaging apparatus6 strengthening the adhesion between the annulus and theengaging apparatus6. However, other surface geometries which facilitate tissue anchoring into the engaging apparatus may also be used, including but not limited to serrated, hooked, porous or folded surfaces. A tube with holes or serrations cut therein (not shown) may also be used.
• In some embodiments, thetightening wire20 may be made of silk or plastic, however, any material with sufficient strength, elasticity and biocompatibility may be used for this purpose. As used herein, the term “wire” includes all such materials and constructions. Thewire20 may be used for subsequent tightening of the engaging apparatus6 (e.g., by pulling on both ends of the wire) leading to a tightening of the annulus of the patient's heart.
• FIG. 7 shows a detailed view of a second embodiment of an engaging apparatus. This embodiment is similar to theFIG. 6 embodiment discussed above, but anchors24 are added to the spring likering18 for initial anchoring of the engagingapparatus56 to the annulus to better withstand cardiac contraction, valve motion and blood flow. One type of anchoring element—a two pronged, open endedminiature spring26—is shown in the insert A, but alternative anchors may be used instead. Any of the delivery systems described above may be used to position the engagingapparatus56 at the annulus and fix it in place by gentlecentripetal pressure4 alone or in conjunction with any existing placing and anchoring technique or by the use of existing placing and anchoring techniques alone. Alternatively, the engagingapparatus56 may be placed using any other minimally invasive or invasive placement delivery systems.
• Optionally, any of the engaging apparatuses described herein may be coated with an adhesive substance to facilitate integration between the engaging apparatus and the annulus. Optionally, the engaging apparatus may contain hooks, serrations, spokes or sutures for preliminary attachment to the annulus. Examples of suitable structures include, but are not limited to, a closed circular spring with a flexible diameter, open ended semi-circular structures, non circular structures capable of approximation between two or more free tips, and non-continuous structures such as individual tubes connected to the annular rim. Optionally, the engaging apparatus may be made of or elute materials which stimulate or accelerate tissue growth. These materials may include but are not limited to growth factors, pro-inflammatory agents, foreign substances which are immunogenic and lead to an enhanced tissue reaction to the engaging apparatus. Optionally, the engaging apparatus may contain an active electromechanical element, such as a motor or actuator, capable of tightening the engaging apparatus. This active component may be self powered by a battery or by mechanical energy generated by the cardiac muscle or blood flow. The active element may be activated using minimally invasive techniques or non-invasive techniques. In the case of non-invasive activation of the active element, any form of transmitted energy may be used, including but not limited to ultrasound and radiofrequency transmission.
• The delivery systems and engaging apparatuses described herein may be used for repair of a cardiac valve annulus such as a mitral valve annulus using a two step procedure: placing and tightening. The method preferably involves bringing an engaging apparatus into position to the annulus of interest as shown inFIG. 2 orFIG. 4 through a minimally invasive procedure.
• FIG. 8 shows the engagingapparatus56 fromFIG. 7 in location at themitral annulus2 immediately after being left in place and anchored to the tissue using the delivery system described above or any other minimally invasive or invasive placement delivery system. No tissue healing or remodeling has occurred at this stage and theengaging apparatus6 is attached to theannulus2 with the minimal necessary force.
• FIG. 9 shows the same engagingapparatus56 after being left in place for sufficient time for tissue healing and remodeling to occur28. At this point the engagingapparatus56 is integrated into theannulus2 due to tissue healing which has embedded the engaging apparatus within the annular wall. Thistissue healing28 embeds the engagingapparatus56 within the wall of theannulus2 with sufficient integration to allow for subsequent tightening of the engaging apparatus56 (e.g., by pulling on both ends of thewire20, shown inFIG. 7) to circumferentially tighten theannulus2. The anchoring strength of the engaging apparatus to the annulus at this stage is preferably sufficient to withstand tightening of the engagingapparatus56 and theentire annulus2 in a subsequent procedure.
• By using this procedure (i.e., install, wait for incorporation, then tighten), the initial placement of the engagingapparatus56 at theannulus2 requires anchoring strength much lower than that used for existing minimally invasive annuloplasty techniques. The initial anchoring strength is sufficient to withstand the normal shear-forces, flow and contraction of the beating heart but, may be less than that necessary for tightening theannulus2. The tightening procedure is subsequently performed during a second procedure after allowing a sufficiently long period of time for tissue remodeling28 into and around the engaging apparatus. It is expected that one week should be sufficient, but it may be possible to use a shorter waiting time in some circumstances.
• Alternatively, in embodiments that rely on adhesion the second step of tightening the engagingapparatus56 may be performed during the same procedure after allowing sufficient time for adhesion to occur between the engagingapparatus56 and theannular tissue2. The tightening procedure may also be performed in any number of subsequent procedures or non-invasively through the chest wall. Optionally, the engagingapparatus56 may deliver energy or focus externally transmitted energy to theannular surface2 in order to accelerate tissue growth into or around the engagingapparatus28.
• FIG. 10 shows yet another embodiment in which the engagingapparatus66 contains an integralanchoring delivery system30 which allows for anartificial valve32 to be connected to the engagingapparatus66, during a subsequent procedure, instead of or in addition to tightening of the annulus. The illustrated delivery system may be used for replacement of a cardiac valve, such as the mitral valve using a three step procedure: widening of the annulus, placing the engagingapparatus66, and anchoring anartificial valve32 to the engagingapparatus66. Introduction of theartificial valve32 to the engaging apparatus may be performed through an intra-vascular or minimally invasive approach.
• FIG. 11 shows theFIG. 10 embodiment where theartificial valve32 is anchored to the engagingapparatus66 during a subsequent, minimally invasive procedure. Optionally, the engagingapparatus66 may be placed at theannulus2 as a second step procedure following widening of theannulus2 andvalve8 using a minimally invasive balloon inflation technique or any other method for widening a stenotic valve. Subsequently, theartificial valve32 may be attached to the engagingapparatus66 during a third procedure, instead of or in addition to tightening of theannulus2.
• All of the above-described embodiments advantageously permit blood flow during insertion of the delivery system and the engaging apparatus.

Claims (14)

1. An apparatus for repairing an annulus comprising:

an annulus contact portion having an outer boundary that is configured for pressing outwards against the annulus, wherein the annulus contact portion is substantially arc-shaped and has an inner core; and

a wire that runs through the inner core and is arranged with respect to the annulus contact portion so that pulling on the wire causes the outer boundary to contract.

2. The apparatus ofclaim 1, wherein the annulus contact portion has a plurality of barbs configured to promote attachment of the annulus contact portion to the annulus.

3. The apparatus ofclaim 1, wherein the substantially arc-shaped annulus contact portion subtends an angle of at least 180°.

4. The apparatus ofclaim 1, wherein the substantially arc-shaped annulus contact portion subtends an angle of at least 270°.

5. The apparatus ofclaim 1, wherein annulus contact portion comprises a helical spring that has been formed into an arc.

6. The apparatus ofclaim 5, wherein the helical spring has an outer diameter between about 25 and about 60 mm, a helix diameter between about 1 and about 3 mm, and a helix pitch between about 1 and about 3 mm.

7. The apparatus ofclaim 5, wherein the annulus contact portion has a plurality of barbs configured to promote attachment of the annulus contact portion to the annulus.

8. The apparatus ofclaim 5, wherein the substantially arc-shaped annulus contact portion subtends an angle of at least 180°.

9. The apparatus ofclaim 5, wherein the substantially arc-shaped annulus contact portion subtends an angle of at least 270°.

10. An apparatus for repairing an annulus comprising:

an annulus contact portion having an outer boundary that is configured for pressing outwards against the annulus, wherein the annulus contact portion is substantially arc-shaped and has an inner core;

a wire that runs through the inner core and is arranged with respect to the annulus contact portion so that pulling on the wire causes the outer boundary to contract; and

a pressing member configured to press the annulus contact portion against the annulus while simultaneously permitting blood to flow therethrough.

11. The apparatus ofclaim 10, wherein the pressing member comprises an inflatable balloon configured to be positioned within the annulus contact portion so that inflation of the balloon cause the annulus contact portion to press against the annulus, and wherein the balloon has a channel that permits blood to flow therethrough when the balloon is inflated.

12. The apparatus ofclaim 11, wherein annulus contact portion comprises a helical spring that has been formed into an arc.

13. The apparatus ofclaim 10, wherein the pressing member comprises a multi-pronged structure adapted to press the annulus contact portion against the inner surface of the annulus when actuated, without blocking off the flow of blood.

14. The apparatus ofclaim 13, wherein annulus contact portion comprises a helical spring that has been formed into an arc.

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