Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Light application
Reexamination Certificate
2001-12-19
2004-05-25
Dvorak, Linda C. M. (Department: 3739)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Light application
C606S002000, C606S013000, C606S015000, C607S090000, C607S092000, C607S101000, C607S102000
Reexamination Certificate
active
06740107
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to devices for shrinking collagen in body tissue. More particularly, the invention relates to catheter devices for shrinking the chordae tendineae of the heart.
BACKGROUND OF THE INVENTION
The human heart consists of four muscular chambers: the right atrium, which connects to the right ventricle, and the left atrium, which connects to the left ventricle. The pumping action of the heart is achieved by contraction and relaxation of the heart muscles. The filling stage of the heart cycle is called diastole. The pumping stage is called systole. Both atria are filled at the same time during diastole and both ventricles expel their blood at the same time during systole.
During diastole, the heart chambers are at their largest volumes, and the atrioventricular valves, which separate the atria from the ventricles, are open. During systole, the heart muscles of the atria contract first, forcing their contents into the ventricles, and then, as the ventricles begin to contract, the increased ventricular pressure forces the atrioventricular valves to close, and the semilunar valves into the arteries to open, so that blood flows out of the heart and into the body tissues. Oxygen depleted blood is forced from the right ventricle into the lungs through the pulmonary artery, and oxygen rich blood is forced from the left ventricle into the remainder of the body through the aortic artery.
Each atrioventricular valve is composed of leaflets of connective tissue, called cusps, which are connected to the heart muscle tissue at the annulus of the aperture between the atrium and the ventricle. The unconnected portions of the cusps overlap with each other when the valves are in the closed position, such that the aperture between the chambers is completely closed. The cusps are stabilized and operated by roughly conical shaped muscles extending from the floor of the ventricles, called papillary muscles, which are connected to the cusps by fibrous, tendon-like structures called chordae tendineae (chordae). There is at least one papillary muscle for each cusp. The chordae begin at the apex of the cone of the papillary muscle and fan upward roughly to the periphery of the cusp. The chordae tendineae are the “guy wires” for the cusps of the atrioventricular valves. The mitral valve, between the left atrium and ventricle, has two cusps, while the tricuspid valve, between the right atrium and ventricle, has three cusps.
The pumping efficiency of the heart can be greatly diminished if the atrioventricular valves malfunction, allowing leakage of the blood from ventricle to atrium. A particularly common problem is weakening or stretching of the chordae, which condition allows the cusps of the affected atrioventricular valves to prolapse into the atrium during systole. Valve prolapse lowers the pumping efficiency of the heart by allowing a portion of the blood to flow in the wrong direction. Valve prolapse is particularly common with the mitral valve, a condition known as primary mitral valve regurgitation, but can also occur with the tricuspid valve. Other conditions which cause mitral valve malfunction include excessive lengthening or thickening of the cusps and the annulus of the valve becoming stretched or loose. Malfunction of the mitral valve occurs in an estimated 1.4% of the population and can lead to a variety of problems, including weakness, persistent nausea, atrial or ventricular fibrillation, a greater risk of infective endocarditis, congestive heart failure, and increased risk of sudden death.
Co-owned U.S. Pat. No. 5,989,284 to Laufer discloses a method of treating primary mitral value regurgitation by applying thermal energy to shorten the chordae. The method of Laufer involves insertion of a catheter into the ventricle of the heart, and placing the tip of the catheter in contact with the chordae. Shortening of the chordae can prevent prolapse of the atrioventricular valve cusps.
The chordae of the human heart are composed predominantly of tightly coiled strands of collagen. Application of heat to the chordae, raising the temperature of the tissue to about 50-55° C., causes the collagen strands to uncoil and straighten. Upon cooling the collagen resumes its tightly coiled shape, however, the collagen strands tend to entangle with one another, causing the total volume of the collagen, and thus the chordae, to shrink. Shrinkage of the chordae can be an effective treatment of primary mitral regurgitation and the related problem of tricuspid valve regurgitation. Likewise, heating the cusps or the annulus, which also contain collagen, to about 50-55° C., causes the collagen therein and the cusps or annulus to shrink in size and length.
The present invention provides catheter devices for shrinkage of tissue, such as the chordae, cusps or annulus of valves of the human heart and other tissues, such as the esophagus in the area of the sphincter or the female urethra below the bladder. Heat is applied to the target tissue via a heat transfer means on the catheter tip. The method of Laufer is a minimally invasive means of treating mitral regurgitation, however, appropriate placement of the catheter tip, and keeping it in place can be difficult, particularly in a moving organ, such as the heart.
In some applications, it is possible to visualize the tissue during laser treatment by means of an endoscope. This is not possible in a beating heart, due to the opaque nature of blood. In addition, the chordae are difficult to visualize by ultrasonic or x-ray techniques, thus, application of energy to the chordae, as in the method of Laufer, must be performed “blind.” A similar problem exists in treatments of female stress incontinence (FSI) involving thermal shrinkage of the tissue surrounding the urethra below the bladder. The small diameter of the urethra (about 1.5 to 5 millimeters) makes endoscopic viewing difficult. It would also be beneficial to shrink tissues such as the esophagus in the area of the sphincter to treat gastro-esophageal reflux disease (GERD).
It would be desirable to be able to shrink the chordae tendineae of the heart and other tissues in a minimally invasive, non-surgical catheterization procedure that would allow precise and stable placement and application of energy to the tissues. It would also be desirable to provide a treatment that could be rendered in a few minutes in a hospital cardiac catheterization laboratory or outpatient department or an outpatient surgical center, with little recuperation time.
SUMMARY OF THE INVENTION
A catheter device suitable for shrinking chordae tendineae of the human heart is provided with an energy conduit (e.g., an optical fiber, electrical conducting cable, or other similar energy transmitting device) and a positioner device that facilitates the delivery of thermal energy to a predetermined region of the chordae tendineae.
In a preferred embodiment, a catheter containing an optical fiber, having a distal end portion encompassing a directional energy emitting device within an asymmetrically-shaped balloon, positions the energy conduit and directionally delivers energy to tissues. The asymmetric shape of the balloon allows an operator to precisely determine the orientation of the device within the tissue using ultrasound or x-ray imaging, for example. The distal end of the catheter is closed and has a blunt shape. The distal end portion of the catheter within the balloon contains an aperture that admits inflation fluid into the balloon, and directs the energy emission from optical fiber through only one portion of the asymmetric balloon. Thus, by imaging the inflated balloon within the tissue, the operator can determine the direction of laser energy emission.
In another embodiment of the present invention a fiber optic cable or other thermal energy delivery device is contained within a tubular sheath that is open at its distal end, such that laser or other thermal energy can be emitted by the cable through the distal opening of the sheath. Also present within the sheath is a flexible metal positioner and s
Crawford L. Dean
Graham Randy P.
Loeb Marvin P.
Dvorak Linda C. M.
Olson & Hierl Ltd.
Roane Aaron
Trimedyne, Inc.
LandOfFree
Device for treatment of atrioventricular valve regurgitation does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for treatment of atrioventricular valve regurgitation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for treatment of atrioventricular valve regurgitation will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3209385