DEVICE AND METHOD FOR TREATMENT OF MITRAL INSUFFICIENCY
A device for treatment of mitral annulus dilatation comprises an elongate body having two states. In a first of these states the elongate body is insertable into the coronary sinus and has a shape adapting to the shape of the coronary sinus. When positioned in the coronary sinus, the elongate body is transferable to the second state assuming a reduced radius of curvature, whereby the radius of curvature of the coronary sinus and the radius of curvature as well as the circumference of the mitral annulus is reduced.
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The present application is a continuation of U.S. patent application Ser. No. 11/841,782, filed Aug. 20, 2007, which is a continuation of U.S. patent application Ser. No. 10/953,047, filed Sep. 29, 2004, now U.S. Pat. No. 7,311,728 which is a continuation of U.S. patent application Ser. No. 10/019,563, filed Jul. 1, 2002, now U.S. Pat. No. 7,044,967, which is a national stage under 35 U.S.C. §371 of international application PCT/SE00/01369, filed Jun. 28, 2000 which designated the United States, and which international application was published under PCT Article 21(2) in the English language and which claims priority to SE 9902455-6, filed Jun. 29, 1999, the disclosures of which are incorporated fully herein by reference.FIELD OF THE INVENTION
The present invention generally relates to a device and a method for treatment of mitral insufficiency and, more specifically, for treatment of dilatation of the mitral annulus.BACKGROUND
Mitral insufficiency can result from several causes, such as ischemic disease, degenerative disease of the mitral apparatus, rheumatic fever, endocarditis, congenital heart disease and cardiomyopathy. The four major structural components of the mitral valve are the annulus, the two leaflets, the chordae and the papillary muscles. Any one or all of these in different combinations may be injured and create insufficiency. Annular dilatation is a major component in the pathology of mitral insufficiency regardless of cause. Moreover, many patients have a mitral insufficiency primarily or only due to posterior annular dilatation, since the annulus of the anterior leaflet does not dilate because it is anchored to the fibrous skeleton of the base of the heart.
Studies of the natural history of mitral insufficiency have found that totally asymptomatic patients with severe mitral insufficiency usually progress to severe disability within five years. At present the treatment consists of either mitral valve replacements or repair, both methods requiring open heart surgery. Replacement can be performed with either mechanical or biological valves.
The mechanical valve carries the risk of thromboembolism and requires anticoagulation, with all its potential hazards, whereas biological prostheses suffer from limited durability. Another hazard with replacement is the risk of endocarditis. These risks and other valve related complications are greatly diminished with valve repair.
Mitral valve repair is theoretically possible if an essentially normal anterior leaflet is present. The basic four techniques of repair include the use of an annuloplasty ring, quadrangular segmental resection of diseased posterior leaflet, shortening of elongated chordae, and transposition of posterior leaflet chordae to the anterior leaflet.
Annuloplasty rings are needed to achieve a durable reduction of the annular dilatation. All the common rings are sutured along the posterior mitral leaflet adjacent to the mitral annulus in the left atrium. The Duran ring encircles the valve completely, whereas the others are open towards the anterior leaflet. The ring can either be rigid, like the original Carpentier ring, or flexible but non-elastic, like the Duran ring or the Cosgrove-Edwards ring.
Effective treatment of mitral insufficiency currently requires open-heart surgery, by the use of total cardiopulmonary by-pass, aortic cross-clamping and cardioplegic arrest.
To certain groups of patient, this is particular hazardous. Elderly patients, patients with a poor left ventricular function, renal disease, severe calcification of the aorta, previous cardiac surgery or other concomitant diseases, would in particular most likely benefit from a less invasive approach, even if repair is not complete. The current trend towards less invasive coronary artery surgery, without cardiopulmonary by-pass, as well as PTCA will also call for a development of a less invasive method for repair of the often concomitant mitral insufficiency.SUMMARY
A first object of the present invention is to provide a device and a method for treatment of mitral insufficiency without the need for cardiopulmonary by-pass and opening of the chest and heart.
A second object of the invention is to provide reduction of the mitral annulus using less invasive surgery.
According to the present invention, a device for treatment of mitralis insufficiency comprises an elongate body having such dimensions as to be insertable into the coronary sinus and having two states, in a first state of which the elongate body has a shape that is adaptable to the shape of the coronary sinus, and to the second state of which the elongate body is transferable from the said first state assuming a reduced radius of curvature, whereby the radius of curvature of the coronary sinus is reduced as well as the circumference of the mitral valve annulus, when the elongate body is positioned in the coronary sinus.
Preferably, means are provided for the transfer of the elongate body to the second state by bending and/or shortening it from a larger radius of curvature to a smaller radius of curvature.
The transfer means may comprise-means for bending and/or shortening the elongate body by a preferably asymmetric contraction thereof.
Further, the elongate body may comprise a memory material providing the transfer to the second state.
In a preferred embodiment, the elongate body may comprise a stent. In an alternative embodiment, the device according to the invention may comprise several stent sections and said bending and/or shortening means may comprise wires for shortening the distance between the stent sections.
According to a second aspect, a method of reducing the circumference of the mitral valve annulus comprises the steps of inserting an elongate body into the coronary sinus in the vicinity of the posterior leaflet of the mitral valve, and then providing a bending and/or shortening of the elongate body when positioned in the coronary sinus so as to reduce the curvature of the coronary sinus and thereby reduce the circumference of the mitral valve annulus.
Thus, the present invention takes advantage of the position of the coronary sinus being close to the mitral annulus. This makes repair possible by the use of current catheter-guided techniques.
The coronary veins drain blood from the myocardium to the right atrium. The smaller veins drain blood directly into the atrial cavity, and the larger veins accompany the major arteries and run into the coronary sinus which substantially encircles the mitral orifice and annulus. It runs in the posterior atrioventricular groove, lying in the fatty tissue between the left atrial wall and the ventricular myocardium, before draining into the right atrium between the atrial septum and the post-Eustachian sinus.
In an adult, the course of the coronary sinus may approach within 5-15 mm of the medial attachment of the posterior leaflet of the mitral valve. Preliminary measurements performed at autopsies of adults of normal weight show similar results, with a distance of 5.3±0.6 mm at the medial attachment and about 10 mm at the lateral aspect of the posterior leaflet. The circumference of the coronary sinus was 18.3±2.9 mm at its ostium (giving a diameter of the posterior leaflet of 5.8±0.9 mm) and 9.7±0.6 mm along the lateral aspect of the posterior leaflet (corresponding to a diameter of 3.1±0.2 mm).
The invention will be better understood by the following description of preferred embodiments referring to the appended drawings, in which
The device of
The elongate body 8 is forced into a stretched or extended state by means of a stabilizing instrument 12 shown in
The arms 13 are free to move between the position shown in
The rod 15 may be a metal wire which is relatively stiff between the distal end 14 and the locking means 16 but still so bendable that it will follow the shape of the coronary sinus 5. Proximally of the locking means 16 the metal wire of the stabilizing instrument 11 is more pliable to be able to easily follow the bends of the veins.
The above-described elongate body 8 is positioned in the coronary sinus 5 in the following way:
An introduction sheet (not shown) of synthetic material may be used to get access to the venous system. Having reached access to the venous system, a long guiding wire (not shown) of metal is advanced through the introduction sheet and via the venous system to the coronary sinus 5. This guiding wire is provided with X-ray distance markers so that the position of the guiding wire in the coronary sinus 5 may be monitored.
The elongate body 8 is locked onto the stabilizing instrument 12, as shown in
A catheter 21, shown in
The third embodiment of the elongate body 8″, illustrated in
Concludingly, the present invention provides a device placed in the coronary sinus, designed to reduce the dilatation of the mitral annulus. This device is at a distance from the attachment of the posterior leaflet that does not much exceed the distance at which present annuloplasty rings are placed by open surgery techniques, and the coronary sinus is along its entire course large enough to hold such a device. The device could be positioned by catheter technique or any other adequate technique and offers a safer alternative to the current open surgery methods. The device could be designed or heparin-coated so as to avoid thrombosis in the coronary sinus, thus reducing the need for aspirin, ticlopedine or anticoagulant therapy.
It is to be understood that modifications of the above-described device and method can be made by people skilled in the art without departing from the spirit and scope of the invention.
1. A medical apparatus for remodeling a mitral valve annulus, comprising:
- an elongate body having a proximal end region and a distal end region, the elongate body having a first configuration for delivery via a catheter to a location adjacent a mitral valve annulus, the elongate body having a second configuration for reshaping the mitral valve annulus to improve coaption of the mitral valve leaflets; and
- a forming element attached to the elongate body for manipulating the elongate body from the first configuration to the second configuration;
- wherein the proximal and distal end regions of the elongate body are configured to be anchored to opposing regions of tissue adjacent the mitral valve annulus and wherein the elongate body urges the opposing regions of tissue together when manipulated to the second configuration.
2. The medical apparatus of claim 1, wherein the forming element is connected to the elongate body at a point of attachment and the forming element is movable relative to the elongate body in order to adjust the elongate body between the first and second configurations.
3. The medical apparatus of claim 2, wherein the forming element is configured to be maneuvered from outside the vein system for adjusting the elongate body.
4. The medical apparatus of claim 1, wherein the elongate body is sized for advancement at least partially into a coronary sinus.
5. The medical apparatus of claim 1, further comprising a coating on the elongate body for avoiding thrombosis.
6. The medical apparatus of claim 1, wherein the apparatus is movable from the first configuration to the second configuration in response to proximal retraction of the forming element.
7. The medical apparatus of claim 1, wherein the apparatus is movable from the first configuration to the second configuration in response to distal movement of the forming element.
8. The medical apparatus of claim 1, further comprising a first stent along the proximal end region of the elongate body and a second stent along the distal end region of the elongate body.
9. The medical apparatus of claim 8, wherein the first and second stents are expandable for engaging a vessel wall.
10. The medical apparatus as in claim 8, wherein the forming element is coupled to the proximal end region of the elongate body.
11. A medical apparatus for remodeling a mitral valve annulus, comprising:
- an elongate body having a first anchor and a second anchor, the elongate body having a first configuration for delivery through a catheter and a second configuration for reshaping the mitral valve annulus to improve coaption of the mitral valve leaflets;
- wherein the first and second anchors of the elongate body are configured to be fixed to opposing regions of tissue adjacent the mitral valve annulus and wherein the elongate body urges the opposing regions of tissue together when in the second configuration.
12. The medical apparatus of claim 11, wherein the first and second anchors include tissue penetrating members.
13. A medical apparatus for remodeling a mitral valve annulus, comprising an elongate body having a substantially fixed length, the elongate body being sized for insertion at least partially into a coronary sinus, wherein the elongate body is configured to change curvature after insertion into the coronary sinus for exerting a compressive force on the mitral valve annulus.
14. The medical apparatus of claim 11, wherein the elongate body comprises a generally U-shaped member formed of a resilient material.
International Classification: A61F 2/82 (20060101);