Surgery – Cardiac augmentation
Reexamination Certificate
2000-10-06
2004-04-20
Jastrzab, Jeffrey R. (Department: 3762)
Surgery
Cardiac augmentation
Reexamination Certificate
active
06723038
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to devices and related methods for improving the function of heart valves, and more particularly to devices and related methods that passively assist in the apposition of heart valve leaflets to improve valve function of poorly functioning valves.
2. Description of the Related Art
Heart failure is a condition whereby the left ventricle becomes enlarged and dilated as a result of numerous etiologies. Initial causes of heart failure include chronic hypertension, myocardial infarction, mitral valve incompetency, and other dilated cardiomyopathies. With each of these conditions, the heart is forced to overexert itself in order to provide the cardiac output demanded from the body during its various demand states. The result is an enlarged left ventricle.
A dilated heart, and particularly a dilated left ventricle, can significantly increase the tension and/or stress in the heart wall both during diastolic filling and systolic contraction, which contributes to ongoing dilatation of the chamber. Prior treatments for heart failure include pharmacological treatments, assist devices such as pumps, and surgical treatments such as heart transplant, dynamic cardiomyoplasty, and the Batista partial left ventriculectomy. These prior treatments are described briefly in U.S. Pat. No. 5,961,440 to Schweich, Jr. et al., issued Oct. 5, 1999 and entitled “Heart Wall Tension Reduction Apparatus and Method,” the complete disclosure of which is incorporated by reference herein.
A more recent concept for treating heart failure applies one or more splints onto the heart, and particulary the left ventricle, to reduce the myocardial muscular stresses encountered during pumping. Many examples of such approaches are disclosed in the if incorporated U.S. Pat. No. 5,961,440. One example includes one or more transventricular splints placed across the left ventricle. Each splint may include a tension member extending across the ventricle and anchors disposed on opposite ends of the tension member and placed on the external surface of the heart.
Mitral valve incompetency or mitral valve regurgitation is a common comorbidity of congestive heart failure. As the dilation of the ventricle proceeds, valve function may worsen. The resultant volume overload condition, in turn, increases ventricular wall stress thereby advancing the dilation process, which may further worsen valve dysfunction.
In heart failure, the size of the valve annulus (particularly the mitral valve annulus) if increases while the area of the leaflets of the valve remains constant. This may lead to an area of less coaptation of the valve leaflets, and, as a result, eventually to valve leakage. Moreover, in normal hearts, the annular size contracts during systole, aiding in valve coaptation. In heart failure, there is poor ventricular function and elevated wall stress. These effects tend to reduce annular contraction and distort annular size, often exacerbating mitral valve regurgitation. In addition, as the chamber dilates, the papillary muscles (to which the leaflets are connected via the chordae tendonae) may move radially outward and downward relative to the valve, and relative to their normal positions. During this movement of the papillary muscles, however, the various chordae lengths remain substantially constant, which limits the full closure ability of the leaflets by exerting tension prematurely on the leaflets. This condition is commonly referred to as “chordal tethering.” The combination of annular changes and papillary changes results in a poorly functioning valve.
It has been observed that for at least certain placements, or orientations, of the one or more transventricular splints in humans, a pre-existing mitral valve incompetency can be exacerbated by the presence and impact of the tightened splints. The splints and the local deformation they impart may further alter the positions of the papillary muscles in such a way that the chordae do not allow as complete of a closure of the mitral valve, or that rotation of portions of the ventricular wall (to which additional chordae may be attached) may “tighten” one valve leaflet and “loosen” the other. In this manner, the leaflets may not close at the same level relative to the annulus, causing increased retrograde leakage through the valve.
Even in instances where the placement of splints does not contribute to further mitral valve leakage, it may be desirable to provide a therapy which could also correct the valve incompetency. A heart with even a small amount of regurgitation may benefit from not only the stress reducing functions of the ventricular splints as described above, but also from the elimination of the regurgitation, which will further off-load the pumping requirements of the myocardium.
While currently available methods of mitral valve repair or replacement are possible to employ in conjunction with ventricular splinting, they typically require opening the heart to gain direct access to the valve and its annulus. This type of access necessitates the use of cardiopulmonary bypass, which can introduce additional complications to the surgical procedure. Since the implantation of the splints themselves do not require the patient to be on cardiopulmonary bypass, it would be advantageous to devise a technique which could improve the mitral valve without the need for cardiopulmonary bypass. The ability to improve the mitral valve function without the need for cardiopulmonary bypass would be an advantage, both in conjunction with ventricular splinting, and also as a stand-alone therapy.
SUMMARY OF THE INVENTION
Objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. To achieve the objects and in accordance with the purpose of the invention, as embodied and broadly described herein, one aspect of the invention comprises a method for improving the function of a valve of a heart. The method includes the steps of placing an elongate member transverse a heart chamber so that each end of the elongate member extends through a wall of the heart, and placing first and second anchoring members external to the chamber. The first and second anchoring members are attached to first and second ends of the elongate member to fix the elongate member in a position across the chamber so as to reposition papillary muscles within the chamber.
According to another aspect, the invention comprises a method for improving the function of a valve of a heart. The method includes the steps of placing an elongate member transverse a heart chamber so that a first end of the elongate member extends through a wall of the heart between two papillary muscles, and a second end of the elongate member extends through a septum of the heart; placing a first anchoring member external the heart; and placing a second anchoring member inside the heart adjacent the septum. The first and second anchoring members are attached to the first and second ends of the elongate member respectively to fix the elongate member in a position across the heart chamber.
According to a further aspect, the invention comprises a method for improving the function of a valve of a heart. The method includes the steps of placing an elongate member transverse a heart chamber so that each end of the elongate member extends through a wall of the heart; and placing first and second anchoring members external the chamber. The first and second anchoring members are attached to the ends of the elongate member to fix the elongate member in a position across the chamber. The position is superior to the papillary muscles and proximate and substantially across the valve.
According to an even further aspect, the invention comprises a splint for improving the function of a valve
Kalgreen Jason E.
Mortler Todd J.
Schroeder Richard F.
Schweich, Jr. Cyril J.
Vidlund Robert M.
Finnegan Henderson Farabow Garrett & Dunner LLP
Jastrzab Jeffrey R.
Myocor, Inc.
Oropeza Frances P.
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