Catheter-Based Annuloplasty System and Method
A catheter-based annuloplasty system for use in repairing a heart valve having leaflets and a valve annulus, includes a delivery catheter having a proximal end and a distal end, and an expandable stent disposed on the distal end of the catheter. An adjustable annuloplasty ring is disposed on the expandable stent and is configured to expand and contract in response to expansion and contraction of the stent.
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The present invention relates generally to annuloplasty prostheses and methods for repair of heart valves. More particularly, it relates to annuloplasty rings, and related instruments and procedures, for reconstructing and remodeling a valve annulus of a patient's heart, for example a mitral valve annulus.
Heart valves, such as the mitral, tricuspid, aortic, and pulmonary valves, are sometimes damaged by disease or by aging, resulting in problems with the proper functioning of the valve. Heart valve problems generally take one of two forms: stenosis, in which a valve does not open completely or the opening is too small, resulting in restricted blood flow; or insufficiency or regurgitation, in which blood leaks backward across a valve that should be closed.
Annuloplasty prostheses, generally categorized as either annuloplasty rings or annuloplasty bands, are employed in conjunction with valvular reconstructive surgery to assist in the correction of heart valve defects such as stenosis and valvular insufficiency. There are two atrio-ventricular valves in the heart. The mitral valve is located on the left side of the heart, and the tricuspid valve is located on the right side. Anatomically speaking, each valve type forms or defines a valve annulus and valve leaflets.
Both valves can be subjected to or incur damage that requires the valve in question be repaired or replaced. The effects of valvular dysfunction vary. For example, mitral regurgitation, a complication of end-stage cardiomyopathy, has more severe physiological consequences to the patient as compared to lone tricuspid valve regurgitation. Regardless, many of the defects are associated with dilation of the valve annulus. This dilation not only prevents competence of the valve, but also results in distortion of the normal shape of the valve orifice. Remodeling of the annulus is therefore central to most reconstructive procedures on the mitral and tricuspid valves. In this regard, clinical experience has shown that repair of the valve, when technically possible, produces better long-term results as compared to valve replacement.
Many procedures have been described to correct the pathology of the valve leaflets and their associated chordae tendinae and papillary muscles. For example, with respect to the mitral valve, two leaflets are present, the anterior leaflet and the posterior leaflet, such that the mitral valve annulus is commonly described as having an anterior aspect and a posterior aspect. With this in mind, in mitral repairs, it is considered important to preserve the normal distance between the two fibrous trigones. The trigones essentially straddle the anterior aspect of the annulus. A significant surgical diminution of the inter-trigonal distance may cause left ventricular outflow obstruction. Thus, it is desirable to maintain the natural inter-trigonal distance during and following mitral valve repair surgery.
Consequently, when a mitral valve is repaired, the result is generally a reduction of the size of the posterior aspect of the mitral valve annulus. As part of the mitral valve repair, the involved segment of the annulus is diminished (i.e., constricted) so that the leaflets may coapt correctly on closing, or the annulus is stabilized to prevent post-operative dilation from occurring, either as frequently achieved by implantation of a prosthetic ring or band at the level of the valve annulus in the atrium. The purpose of the ring or band is to restrict and/or support the annulus to correct and/or prevent the valvular insufficiency. However, it is important not to overly restrict the annulus as an unacceptable valvular stenosis or Systolic Anterior Motion (SAM) of the anterior leaflet may result. In tricuspid valve repair, constriction of the annulus usually takes place in a posterior leaflet segment and in a small portion of the adjacent anterior leaflet. The septal leaflet segment is not usually required to be shortened.
Previously, valve repair or replacement required open-heart surgery with its attendant risks, expense, and extended recovery time. Open-heart surgery also requires cardiopulmonary bypass with risk of thrombosis, stroke, and infarction. More recently, flexible valve prostheses and various delivery devices have been developed so that replacement valves can be implanted transvenously using minimally invasive techniques.
SUMMARYOne embodiment is directed to a catheter-based annuloplasty system for use in repairing a heart valve having leaflets and a valve annulus in a beating heart. The system includes a delivery catheter having a proximal end and a distal end, and an expandable stent disposed on the distal end of the catheter. An adjustable annuloplasty ring is disposed on the expandable stent and is configured to expand and contract in response to expansion and contraction of the stent. In one embodiment, the delivery catheter is configured to deliver the annuloplasty ring to the endocardial surface of the valve annulus.
Another embodiment is directed to an annuloplasty prosthesis for repairing a heart valve having a valve annulus. The annuloplasty prosthesis includes an adjustable ring comprising a plurality of interconnected cylindrically-shaped ring segments, and has a first end co-axially aligned with and inserted into a second end of the adjustable ring. A plurality of tissue attachment members is attached to the adjustable ring. The tissue attachment members are shaped for penetration into the valve annulus and are configured to be triggered from a tension state to a relaxed state.
Yet another embodiment is directed to a method of repairing a heart valve comprising leaflets and a valve annulus. The method includes delivering an adjustable ring having tissue attachment members to a location adjacent to the heart valve via a catheter, and extending a self-expanding stent outside of the catheter, thereby causing an expansion of the adjustable ring. The tissue attachment members are triggered, thereby causing the adjustable ring to be anchored to the valve annulus. The self-expanding stent is contracted, thereby causing a reduction in size of the adjustable ring and the valve annulus. The adjustable ring is locked into position and the delivery catheter is removed.
The terms “distal” and “proximal” are used herein with reference to the treating clinician during the use of the catheter system; “Distal” indicates an apparatus portion distant from, or a direction away from the clinician and “proximal” indicates an apparatus portion near to, or a direction towards the clinician. Additionally, the term “annuloplasty” is used herein to mean modification/reconstruction of a defective heart valve.
Embodiments disclosed herein include devices and methods for treating regurgitation in cardiac valves. While these devices and methods are described below in terms of being used to treat mitral regurgitation, it will be apparent to those skilled in the art that the devices could also be used on other cardiac valves. Embodiments disclosed herein include minimally-invasive, off-pump, catheter-based systems and methods for attaching a prosthetic ring to the annulus of the mitral valve of a beating heart, and adjusting the ring, thereby reshaping the mitral valve annulus so that the anterior and posterior leaflets of the mitral valve co-apt during ventricular contraction.
Stent 202 and catheter 204 comprise a catheter-based delivery system 210 for delivering ring 206 adjacent to a valve annulus for attachment thereto. The catheter 204 includes a proximal end and a distal end. The stent 202 is disposed on the distal end of the catheter 204. The stent 202 and the ring 206 are initially collapsed and thereby reduced in diameter, mounted in the catheter 204, and advanced through the circulatory system of a patient. The ring 206 is disposed on a distal end of the stent 202, and is releasably carried within the delivery catheter 204 to a position near the valve annulus. Stent 202 is then gradually extended beyond the distal tip of the catheter 204. In the illustrated embodiment, stent 202 is a self-expanding stent, and automatically increases in size as it is extended outside of the catheter 204. Stent 202 and tissue attachment retaining members 208 according to one embodiment are formed of a shape memory material. In one embodiment, stent 202 comprises a NITINOL™ framework.
In one embodiment, the ring 206 has an adjustable size (e.g., circumference and diameter), and is configured to be adjusted via stent 202 during and after installation around the valve annulus. The ring 206 is configured to expand and contract in response to expansion and contraction, respectively, of the stent 202. As stent 202 is extended outside of the catheter 204, the expansion of the distal end of the stent 202 causes a corresponding expansion in the ring 206. As stent 202 is returned inside of the catheter 204, the contraction of the distal end of the stent 202 causes a corresponding contraction in the ring 206. Stent 202 is used to adjust the size of ring 206 until the ring 206 reaches an appropriate size for attachment to the valve annulus. When the ring 206 reaches the appropriate size, tissue attachment members 900 (
The tissue attachment members 900 are used to attach the ring 206 to the valve annulus. When ring 206 is in position adjacent to the annulus, stent 202 is pulled away from ring 206, which causes tissue attachment retaining members 208 to be lifted away from prong portions 902A and 902B of the tissue attachment members 900. When tissue attachment retaining members 208 are removed from prong portions 902A and 902B, the prong portions 902A and 902B spring toward the relaxed state (
The minimally-invasive, off-pump, catheter-based annuloplasty system and method described herein provides the ability to intervene with patients in both early disease states or in advanced heart failure, and provides advantages over traditional surgical repair devices because traditional open heart surgery is no longer needed.
Although the present disclosure has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the present disclosure.
Claims
1. A catheter-based annuloplasty system for use in repairing a heart valve having leaflets and a valve annulus, comprising:
- a delivery catheter having a proximal end and a distal end;
- an expandable stent disposed on the distal end of the catheter; and
- an adjustable annuloplasty ring disposed on the expandable stent configured to expand and contract in response to expansion and contraction of the stent, wherein the adjustable ring includes at least one tissue attachment member configured to be attached to the valve annulus via movement of the expandable stent.
2. The annuloplasty system of claim 1, wherein the adjustable ring includes a plurality of tissue attachment members shaped for penetration into the valve annulus and configured to be triggered from a spring-loaded tensioned state to a relaxed state.
3. The annuloplasty system of claim 2, wherein each tissue attachment member comprises:
- a first prong portion extending from a first circular spring portion;
- a second prong portion extending from a second circular spring portion; and
- a cross-member connecting the first and second circular spring portions.
4. The annuloplasty system of claim 3, wherein the adjustable ring extends through the first and second circular spring portions of each of the tissue attachment members.
5. The annuloplasty system of claim 3, wherein the cross-member includes a feature configured to be connected to hold the adjustable ring adjacent to the expandable stent.
6. The annuloplasty system of claim 2, and further comprising:
- a plurality of tissue attachment retaining members disposed on the expandable stent and configured to hold the tissue attachment members in the tensioned state.
7. The annuloplasty system of claim 6, wherein the tissue attachment retaining members are configured to release the tissue attachment members from the tensioned state when the adjustable ring is adjacent to the valve annulus, thereby causing the tissue attachment members to transition to the relaxed state and anchor the adjustable ring to the valve annulus.
8. The annuloplasty system of claim 7, wherein the adjustable ring is configured to be adjusted in size after the adjustable ring has been anchored to the valve annulus.
9. The annuloplasty system of claim 6, wherein the tissue attachment retaining members are formed of a shape memory material.
10. The annuloplasty system of claim 1, wherein the adjustable ring comprises a plurality of interconnected cylindrically-shaped ring segments.
11. The annuloplasty system of claim 10, wherein each of the ring segments includes a plurality of tabs that extend away from a body of the segment parallel to a surface of the adjustable ring.
12. The annuloplasty system of claim 11, wherein adjacent ones of the tabs in each ring segment are separated by a gap, and wherein each tab of each segment is positioned within one of the gaps of an adjacent segment.
13. The annuloplasty system of claim 10, wherein axial twisting of the adjustable ring causes a separation between adjacent segments and an increase in an internal diameter of the adjustable ring.
14. The annuloplasty system of claim 10, wherein a first end of the ring is co-axially aligned with and inserted into a second end of the ring.
15. The annuloplasty system of claim 14, wherein contraction of the stent causes the first end of the ring to extend farther into the second end of the ring, thereby reducing an overall diameter of the adjustable ring.
16. The annuloplasty system of claim 15, and further comprising a locking mechanism configured to lock the adjustable ring and thereby prevent further size adjustments to the ring.
17. The annuloplasty system of claim 16, wherein the locking mechanism is configured to lock a surface of the adjustable ring between asymmetrical lumens within the locking mechanism.
18. The annuloplasty system of claim 1, wherein the stent is a self-expanding stent formed of a shape memory material.
19. The annuloplasty system of claim 1, wherein the stent is a self-expanding NITINOL™ framework.
20. The annuloplasty system of claim 1, wherein the system is configured to be used off-pump to repair the heart valve of a beating heart.
21. A catheter-based annuloplasty system for use in repairing a heart valve having a valve annulus, comprising:
- a delivery catheter having a proximal end and a distal end;
- a stent disposed on the distal end of the catheter;
- a ring positioned on the stent; and
- a plurality of tissue attachment members attached to the ring, the tissue attachment members shaped for penetration into the valve annulus and configured to be triggered from a spring-loaded tensioned state to a relaxed state via movement of the stent.
22. The annuloplasty system of claim 21, wherein each tissue attachment member comprises:
- a first prong portion extending from a first circular spring portion;
- a second prong portion extending from a second circular spring portion;
- a cross-member connecting the first and second circular spring portions; and
- wherein the ring extends through the first and second circular spring portions of each of the tissue attachment members.
23. A method of repairing a heart valve comprising leaflets and a valve annulus, the method comprising:
- delivering a ring having tissue attachment members to a location adjacent to the heart valve via a catheter;
- extending a stent outside of the catheter, thereby causing the ring to be positioned adjacent to the valve annulus; and
- triggering the tissue attachment members via the stent, thereby causing the ring to be anchored to the valve annulus
24. The method of claim 23, wherein the ring is an adjustable ring and the stent is a self-expanding stent, and wherein the method further comprises:
- contracting the self expanding stent after the adjustable ring is anchored to the valve annulus, thereby causing a reduction in size of the adjustable ring and the valve annulus; and
- triggering a locking mechanism on the adjustable ring after causing the reduction in size of the adjustable ring to maintain the reduced size of the ring.
25. The method of claim 23, wherein the method is performed off-pump to repair the heart valve of a beating heart.
Type: Application
Filed: Dec 17, 2012
Publication Date: May 16, 2013
Applicant: MEDTRONIC, INC. (Minneapolis, MN)
Inventor: Medtronic, Inc. (Minneapolis, MN)
Application Number: 13/716,377
International Classification: A61F 2/24 (20060101);