Apparatus and Methods for Occluding a Hallow Anatomical Structure
A clamp (10) having at least first and second elongate clamping portions (2, 4) adapted to be placed on opposite sides of the hollow anatomical structure (40). The first and second elongate clamping portions (2, 4) respectively include ends coupled together with respective resilient urging members (6, 8) configured to urge at least one of the first and second elongate clamping portions (2, 4) toward the other of the first and second elongate clamping portions (2, 4) from an open position into a clamping position to occlude the hollow anatomical structure (40). The clamp (10) is shaped annularly such that it may surround the hollow anatomical structure (40) in the open position and reorient into a flattened shape in the clamping position to occlude the hollow interior of the hollow anatomical structure (40). Apparatus of the invention further include clamp delivery and actuation devices (80, 200) adapted to deploy the clamp (10).
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- APPARATUS AND METHODS FOR OCCLUDING A HOLLOW ANATOMICAL STRUCTURE
This application claims the benefit of U.S. Provisional Application Ser. No. 60/699,309 filed on Jul. 14, 2005, and generally relates to the subject matter disclosed and claimed in U.S. application Ser. No. 10/853,928, filed on May 26, 2004, the disclosures of which are hereby fully incorporated by reference herein.
FIELD OF THE INVENTIONThe present invention relates generally to surgical methods and apparatus for occluding a hollow tissue structure, such as when occluding vessels, or pedunculated structures such as an appendix, gall bladder or appendages on the heart. More specifically, the present invention relates to a method and device for occluding the left atrial appendage of the heart in either an open surgical procedure or minimally invasive procedure.
BACKGROUNDAtrial fibrillation is a common cardiac rhythm disorder that affects more than two million people each year. Until relatively recently, atrial fibrillation was thought to be a nuisance arrhythmia with few consequences. However, recent medical research has uncovered some devastating complications including cardiomyopathy, congestive heart failure and stroke.
During atrial fibrillation the upper part of the heart beats (quivers) faster than the rest of the heart. This phenomenon is due to the generation of erratic or extra electrical signals which cause the top part of the heart to quiver rapidly and irregularly (fibrillate) as many as 300-600 times per minute. However, the entire heart does not beat that fast. The heart is a muscular pump divided into four chambers, with two atria on the top of the heart and two ventricles on the bottom portion of the heart. Normally, the heartbeat starts in the right atrium when a special group of cells sends an electrical signal. These cells are called the sinoatrial or SA node, sinus node or the heart's “pacemaker.” The signal spreads throughout the atria and to the atrioventricular or AV node. The AV node connects to a group of fibers in the ventricles that conduct the electrical signal. The electrical impulse travels via these specialized fibers to all parts of the ventricles. The specialized fibers are also known as the His-Purkinje system. The electrical signal must follow this exact route for the heart to pump properly. Normally, the heart beats at 60-80 times per minute at rest. This number represents the contractions of the lower heart or ventricles. During atrial fibrillation, electrical signals from other parts of the heart disrupt the heart's normal rhythm and cause the atria to quiver or beat too fast. However, only a small number of these atrial beats make it through the AV node, which acts like a gate to the ventricles. This is fortunate, because a rapid ventricular heartbeat would be much more dangerous and potentially fatal. However, some atrial fibrillation does make it through the AV node making the heart beat faster than normal. An atrial fibrillation attack is usually not life threatening. The most significant danger is stroke.
Blood usually moves completely through the chambers of the heart. During atrial fibrillation, the heart is not pumping normally or efficiently. The blood begins to pool in the atria and this stagnation of blood can cause the blood to thicken and form clots. These clots are then ejected out of the heart and into the bloodstream where they can lodge in the brain causing a stroke. Atrial fibrillation can make stroke five times more likely than in the general population. When the heart experiences atrial fibrillation there may not be enough blood pumping to the brain or other organs. This can cause dizziness, shortness of breath or organ failure. Untreated atrial fibrillation will also weaken the heart due to phenomenon known as remodeling. The heart, like the rest of the body, adapts to changes. The fast abnormal rhythm in the atria causes electrical changes, and this can enlarge the heart.
There are three major objectives in the treatment of atrial fibrillation: the restoration of normal sinuous rhythm, control of ventricular rate during atrial fibrillation, and the prevention of blood clot formation. Some methods of treatment for atrial fibrillation include pharmacological therapy, pacemakers, and surgery.
For the prevention of blood clots, research has demonstrated that the anticoagulant warfarin (e.g., Coumadin®) is effective in reducing the risk of blood clot formation and stroke but it does not totally eliminate the risk. An anticoagulant such as warfarin interferes with the body's natural clotting mechanism. The dosage of warfarin is highly individualized and must be carefully monitored with blood tests to ensure safety. While this pharmacological treatment may significantly reduce the risk of stroke, it also increases the risk of bleeding and may be inappropriate for many atrial fibrillation patients.
As an alternative to pharmacological therapy, there are a few surgical procedures that isolate the left atrial appendage from the blood's circulatory system. The left atrial appendage is a small hollow extension (i.e., a pedunculated structure) formed off the lateral wall of the left atrium. It has been referred to as a small “windsock” like structure or a small, flat hollow finger-like protrusion. The left atrial appendage usually contracts with the rest of the left atrium during normal heart function thereby continually moving blood throughout the hollow extension. During atrial fibrillation, the left atrial appendage often fails to contract thereby allowing the blood to pool inside the appendage, becoming stagnated. As a result, the blood becomes thicker and thrombus or clot formation may occur. These clots can be slowly ejected from the left atrial appendage into the left atrium and left ventricle, and then released into the bloodstream thereby becoming an obstruction in the brain or other vascular structures. For this reason, it is advantageous to prevent these clots from forming and being dislodged into the bloodstream. One method of preventing the occurrence of clots is to occlude the appendage thus preventing blood from entering and forming clots. This also prevents clots already formed in the appendage from escaping into the bloodstream. Normally, the occlusion of the left atrial appendage is performed in conjunction with other procedures such as a mitral valve replacement or coronary artery bypass procedure and not as the sole reason for the procedure.
There are several different methods being used today to occlude the left atrial appendage. One method is percutaneous left atrial appendage transcatheter occlusion. A small occlusion device is deployed from a venous access catheter into the left atrium and blocks the opening into the atrial appendage. In order to access the left atrium from the vena cava's right atrium, the surgeon must go through the atrial wall. Many surgeons are uncomfortable with making an opening in this wall without being able to repair it at the end of the procedure. There are also issues of placing an occlusion device inside the heart. If the occlusion device becomes detached within the heart, the result may be fatal.
Another method of occlusion is placing a loop around the left atrial appendage and cinching it down in a manner similar to a garrote. When trying to place a flaccid loop around an irregular pedunculated structure, it can be difficult to make certain the loop is positioned at the base of the appendage. When cinching the loop, it is very easy to over tighten the loop, and this can result in severing the delicate atrial appendage. Even a partial tear can create problems, including the initial problem of gaining access to repair the tear. This method of occlusion may not always seal the opening between the appendage interior and the atrium. That is, there may still be a partial opening due to the way the appendage wall collapses during cinching of the loop. Such a partial opening could still allow some flow into and out of the atrial appendage, leading to the problems mentioned above. In addition, transforming the relatively flat structure of the appendage onto a round hard mass, as does a cinching method, could lead to other problems.
Another method of occlusion is to place a linear surgical stapler at the base of the appendage and a left atrial wall and staple the appendage closed. Due to the limited access, the ability to visualize the entire atrial appendage while placing the stapler in the correct location can be a problem. It is very difficult to make certain the staple line makes a complete occlusion of the appendage. Again, a partial occlusion of the appendage can still result in the formation and dislodgement of clots.
For the aforementioned reasons, it would be desirable to provide improved methods and devices to reliably occlude hollow anatomical structures, including but not limited to the left atrial appendage of the heart, completely and safely. Such methods may be performed during an open-heart surgical procedure such as a valve replacement or coronary artery bypass. It would also be desirable to provide methods and devices that may be used in minimally invasive or less invasive procedures while the heart is beating without placing the patient on a heart-lung bypass machine. A less invasive device may allow, for example, access through either an intercostal space between the ribs or a supra and/or sub-xiphoid approach to gain access to the left atrial appendage. Such devices may allow complete visualization of the left atrial appendage for the surgeon and permit minor placement adjustments to be made before permanent installation is made. The devices would also allow complete occlusion of the left atrial appendage, eliminating the risk of clots forming in the appendage, traveling throughout the bloodstream, and possibly lodging in the brain causing a stroke.
SUMMARYIn one aspect, the present invention is directed to a device for occluding a hollow anatomical structure, with the device including a clamp having at least first and second elongate clamping portions adapted to be placed on opposite sides of the hollow anatomical structure. The first and second elongate clamping portions respectively have ends coupled together with respective resilient urging members configured to urge at least one of the first and second elongate clamping portions toward the other of the first and second elongate clamping portions from an open position into a clamping position to occlude the hollow anatomical structure. The clamp comprises an annular shape configured to surround the hollow anatomical structure in the open position and a flattened shape in the clamping position configured to occlude the hollow interior of the hollow anatomical structure.
The resilient urging members may normally spring bias at least one of the first and second elongate clamping portions toward the other of the elongate clamping portions. For example, any number of designs may be used for the resilient urging members, including various types of separate or integrally formed spring elements on the clamp. One or more generally U-shaped wire sections may be used at opposite ends, for example. The clamping portions may have tissue engaging surfaces adapted to promote tissue ingrowth, such as a tissue engaging surface having pores with diameters sized from about 200 to about 400 microns. The surface may, for example, comprise a surgical grade fabric. The tissue contacting surface may be a surface that prevents line contact with the hollow anatomical structure thereby spreading a load force exerted by the first and second elongate clamping portions on the tissue. The first and second elongate clamping portions may have complementary shapes in cross section such that the complementary shapes fit together in the clamping position. This may be achieved through either a preformed shape in the elongate clamping portions, or by forming one or both the elongate clamping portions, or at least one or more outer layers thereof, out of a material that is deformable under load. Any other features in the above incorporated patent application may also be incorporated into the device as further disclosed herein.
In one aspect, the first and second elongate clamping portions and the resilient urging members may be formed from at least one wire member. The wire member may be formed from a material having superelastic properties, such as a nickel-titanium alloy, or from other materials having suitable physical characteristics for achieving the clamping function. Rigid and/or resilient tubular members may be used to cover the wire member second tubular shaped members can, for example, provide more effective load spreading by increasing the diameter of the wire member.
In another aspect of the invention, tissue blocking members are positioned at opposite ends of the elongate clamping portions and prevent outward egress of clamped tissue beyond the respective ends of the elongate clamping portions.
In another aspect of the invention, the first and second elongate clamping portions may comprise elongate generally parallel members capable of reorienting into a nonparallel relationship in the clamping position. For example, the generally parallel members may reorient into a nonparallel relationship which converges toward one end of the clamp or the other end of the clamp.
Apparatus according to the invention may include a clamp with any of the features discussed above, and a clamp delivery and actuation device including first and second jaws for carrying and deploying the clamp onto the hollow anatomical structure.
Methods according to the invention are also contemplated and generally include use of the device or apparatus as described above including any of the desired features discussed herein.
As shown in
Alternate embodiments show ways to add length to the urging members 66, 68 in order to reduce the overall stress and thus prevent elastic yield of the material. Uses of superelastic material such as nickel titanium alloys are preferred and shown in previous embodiments, not only for its resistance to yielding but also for its biocompatibility. However, it is also possible to use other materials such as a spring-type biocompatible steel. Without departing from the scope of this invention, alternate materials such as plastics, elastomers and metals can be used in the construction of urging members 66, 68 and other portions or components of the various clamps disclosed herein.
While the present invention has been illustrated by a description of various preferred embodiments and while these embodiments have been described in some detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The various features of the invention may be used alone or in any and all combinations depending on the needs and preferences of the user. This has been a description of the present invention, along with the preferred methods of practicing the present invention as currently known.
Claims
1. A device for occluding a hollow anatomical structure, the device comprising:
- a clamp having at least first and second elongate clamping portions adapted to be placed on opposite sides of the hollow anatomical structure, said first and second elongate clamping portions respectively having ends coupled together with respective resilient urging members configured to urge at least one of said first and second elongate clamping portions toward the other of said first and second elongate clamping portions from an open position into a clamping position to occlude the hollow anatomical structure,
- said clamp comprising an annular shape configured to surround the hollow anatomical structure in the open position and a flattened shape in the clamping position configured to occlude the hollow interior of the hollow anatomical structure.
2. The device of claim 1, wherein said resilient urging members normally spring bias at least one of said first and second elongate clamping portions toward the other of said first and second elongate clamping portions when said first and second elongate clamping portions are in the open position.
3. The device of claim 1, wherein said first and second elongate clamping portions have tissue engaging surfaces for engaging the hollow anatomical structure in the clamping position, at least one of said tissue engaging surfaces adapted to promote tissue ingrowth.
4. The device of claim 3, wherein said at least one tissue engaging surface includes pores sized from about 200 to about 400 microns.
5. The device of claim 1, further comprising a fabric covering on at least one of said first and second elongate clamping portions.
6. The device of claim 1, wherein said first and second elongate clamping portions each includes a tissue contacting surface for preventing line contact with the hollow anatomical structure thereby spreading a load force exerted by said first and second elongate clamping portions.
7. The device of claim 1, wherein said first and second elongate clamping portions have complementary shapes in cross section such that said complementary shapes fit together in the clamping position.
8. The device of claim 1, wherein at least one of said first and second elongate clamping portions is convexly curved toward the other of said first and second elongate clamping portions in cross section.
9. The device of claim 1, further comprising projections on at least one of said first and second elongate clamping portions configured to engage the hollow anatomical structure when said clamp is in the clamping position.
10. The device of claim 1, wherein said first and second elongate clamping portions and said resilient urging members are formed from at least one wire member.
11. The device of claim 10, wherein said wire member is formed from a material having superelastic properties.
12. The device of claim 11, wherein said wire member is formed from a nickel-titanium alloy.
13. The device of claim 10, wherein said wire member is formed from steel.
14. The device of claim 10, further comprising first and second tubular shaped members covering said wire member respectively on said first and second elongate clamping portions.
15. The device of claim 10, wherein said resilient urging members each further comprise at least one generally U-shaped curved section in said wire member.
16. The device of claim 1, wherein said first and second elongate clamping portions further comprise elongate generally parallel members capable of reorienting into a nonparallel relationship in the clamping position.
17. The device of claim 1, further comprising tissue blocking members positioned at opposite ends of said elongate clamping portions and configured to present outward egress of clamped tissue beyond the respective ends of said elongate clamping portions.
18. The device of claim 17, wherein the tissue blocking members are formed at least partially from a material that promotes tissue ingrowth.
19. Apparatus for occluding a hollow anatomical structure, the device comprising:
- a clamp delivery and actuation device including first and second jaws, at least one of said first and second jaws configured to move toward and away from the other of said first and second jaws, and
- a clamp configured for attachment to said first and second jaws and having at least first and second elongate clamping portions adapted to be placed on opposite sides of the hollow anatomical structure, said first and second elongate clamping portions respectively having ends coupled together with respective resilient urging members configured to urge at least one of said first and second elongate clamping portions toward the other of said first and second elongate clamping portions from an open position into a clamping position to occlude the hollow anatomical structure,
- said clamp comprising an annular shape configured to surround the hollow anatomical structure in the open position and a flattened shape in the clamping position configured to occlude the hollow interior of the hollow anatomical structure.
20. The apparatus of claim 19, wherein said first and second jaws and said clamp are configured to enable repeated movement of the clamp between the open and closed positions.
21. The apparatus of claim 19, wherein said clamp is releasably held to said first and second jaws by suture.
22. The apparatus of claim 19, wherein the clamp delivery and actuation device further comprises an endoscopic device.
23. A method of occluding a hollow anatomical structure with an annular clamp having at least first and second elongate clamping portions with opposite ends coupled together by respective resilient urging members, the method comprising:
- holding the first and second elongate clamping portions a spaced apart orientation against a bias applied by the resilient urging members,
- surrounding the hollow anatomical structure with the annular clamp, and
- releasing the elongate clamping portions to move the first and second elongate clamping portions together against opposite sides of the hollow anatomical structure under the bias applied by the resilient urging members.
24. The method of claim 23, wherein the hollow anatomical structure is the left atrial appendage of a heart.
25. The method of claim 23, wherein the method further comprises:
- accessing the left atrial appendage of the heart through an intercostal space.
26. The method of claim 23, wherein at least one of said elongate clamping portions further includes a fabric covering, and the method further comprises engaging the fabric covering with the hollow anatomical structure.
27. The method of claim 23, further comprising:
- moving at least one of the first and second elongate clamping portions away from the other of the first and second elongate clamping portions;
- repositioning the annular clamp on the hollow anatomical structure; and
- moving at least one of the first and second elongate clamping portions toward the other of the first and second elongate clamping portions to occlude the hollow anatomical structure.
28. A device for occluding a hollow anatomical structure, the device comprising:
- a clamp having at least first and second elongate clamping portions adapted to be placed on opposite sides of the hollow anatomical structure, said first and second elongate clamping portions respectively having ends coupled together in a manner allowing at least one of said first and second elongate clamping portions to move toward the other of said first and second elongate clamping portions from an open position into a clamping position to occlude the hollow anatomical structure,
- said clamp comprising an annular shape configured to surround the hollow anatomical structure in the open position and a flattened shape in the clamping position configured to occlude the hollow interior of the hollow anatomical structure, and said elongate clamping portions further comprising generally parallel members capable of reorienting into at least first and second nonparallel relationships in the clamping position, said first nonparallel relationship comprising said elongate clamping portions converging toward one end of said clamp and said second nonparallel relationship comprising said elongate clamping portions converging toward an opposite end of said clamp.
Type: Application
Filed: Jul 14, 2006
Publication Date: Jan 8, 2009
Applicants: IDX MEDICAL, LTD. (Loveland, OH), ATRICURE, INC. (West Chester, OH)
Inventors: Warren P. Williamson, IV (Loveland, OH), Jason I. Glithero (Mason, OH), Michael W. Goldenbogen (Floyds Knobs, IN), Chadd R. Tyler (Sellersburg, IN), Todd A. Hall (Goshen, KY)
Application Number: 11/994,725
International Classification: A61B 17/122 (20060101);