U.S. patent application number 12/028714 was filed with the patent office on 2009-06-18 for annuloplasty rings for correcting degenerative valvular diseases.
Invention is credited to David Adams, Alain Carpentier.
Application Number | 20090157176 12/028714 |
Document ID | / |
Family ID | 39493596 |
Filed Date | 2009-06-18 |
United States Patent
Application |
20090157176 |
Kind Code |
A1 |
Carpentier; Alain ; et
al. |
June 18, 2009 |
ANNULOPLASTY RINGS FOR CORRECTING DEGENERATIVE VALVULAR
DISEASES
Abstract
A set of annuloplasty rings progressively sized to take into
account more of the common pathologies. The proportional shapes of
each ring as the orifice size changes vary. For instance, the
larger rings have larger minor axis dimensions relative to their
major axis dimensions.
Inventors: |
Carpentier; Alain; (Paris,
FR) ; Adams; David; (New York, NY) |
Correspondence
Address: |
EDWARDS LIFESCIENCES CORPORATION
LEGAL DEPARTMENT, ONE EDWARDS WAY
IRVINE
CA
92614
US
|
Family ID: |
39493596 |
Appl. No.: |
12/028714 |
Filed: |
February 8, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60889178 |
Feb 9, 2007 |
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Current U.S.
Class: |
623/2.36 |
Current CPC
Class: |
A61F 2/2409 20130101;
A61F 2/2445 20130101; Y10T 29/49 20150115; A61F 2/24 20130101; A61F
2230/0034 20130101; A61F 2/2448 20130101; A61F 2250/0037 20130101;
A61F 2250/0018 20130101; A61F 2230/0065 20130101 |
Class at
Publication: |
623/2.36 |
International
Class: |
A61F 2/24 20060101
A61F002/24 |
Claims
1. A set of mitral annuloplasty rings comprising: a set of closed
and generally rigid ring bodies arranged around a flow axis having
an upward direction and a downward direction, the downward
direction corresponding to the direction of blood flow through the
mitral valve annulus when the annuloplasty ring is implanted, the
ring body being generally D-shaped in plan view and defining a
major axis A and a minor axis B, and each ring having a nominal
orifice size in even mm increments; and wherein the ratio B/A
increases with increasing nominal orifice sizes of the ring
bodies.
2. A set of mitral annuloplasty rings comprising: a set of closed
and generally rigid ring bodies arranged around a flow axis having
an upward direction and a downward direction, the downward
direction corresponding to the direction of blood flow through the
mitral valve annulus when the annuloplasty ring is implanted, the
ring body being generally D-shaped in plan view and defining a
major axis A and a minor axis B, and each ring having a nominal
orifice size in even mm increments; and wherein the proportional
shape of the ring bodies changes with increasing nominal orifice
sizes of the ring bodies.
Description
[0001] The present application claims priority under 35 U.S.C.
.sctn.119(e) to U.S. Provisional Application No. 60/828,458, filed
Oct. 6, 2006.
FIELD OF THE INVENTION
[0002] The present invention refers to a prosthetic annuloplasty
ring or set of rings, in particular for the mitral annulus, that
are progressively proportioned at different orifice sizes.
BACKGROUND OF THE INVENTION
[0003] The human heart has four valves; the aortic valve, the
mitral valve, the pulmonary valve and the tricuspid valve. Various
diseases and certain genetic defects of the heart valves can impair
the proper functioning of the valves. Improper functioning of a
valve can be severely debilitating and even fatal if left
untreated, particularly if the diseased valve is the aortic valve
(between the left ventricle and the aorta) or the mitral valve
(between the left atrium and left ventricle). The common defects
and diseases affecting each of these valves, and the treatments
thereof, are typically different.
[0004] The mitral valve and, less frequently, the tricuspid valve,
are prone to deformation, such as dilation of the valve annulus,
tearing of the chordae tendineae and leaflet prolapse, which
results in valvular insufficiency wherein the valve does not close
properly and allows for regurgitation or back flow from the left
ventricle into the left atrium. Deformations in the structure or
shape of the mitral or tricuspid valve are repairable. Thus,
because prosthetic valves have certain disadvantages that can have
serious effects (e.g., mechanical valves carry the risk of
thromboembolism and require anticoagulation treatment, and
biological valves have limited durability), an improper functioning
mitral or tricuspid valve is ideally repaired rather than
replaced.
[0005] The mitral annulus is a pliable junctional zone of fibrous
and muscular tissue joining the left atrium and left ventricle that
anchors the peripheral hinge portion of the anterior and posterior
mitral leaflets. The annulus has two major collagenous structures:
(1) the right fibrous trigone, which is part of the central fibrous
body and is located at the intersection of the atrioventricular
membranous septum, the mitral and tricuspid valves, and the aortic
root; and (2) the left fibrous trigone at the junction of the
mitral valve and left coronary cusp of the aortic valve. The mitral
valve has two major leaflets, the much larger anterior (or aortic)
leaflet and the smaller posterior (or mural) leaflet. The anterior
mitral leaflet spans the distance between the commissures
(including the trigones) and is in direct fibrous continuity with
most of the left and noncoronary aortic valve cusps. The posterior
one-half to two-thirds of the annulus, which subtends the posterior
leaflet, is primarily muscular with little or no fibrous tissue,
and usually contains three (or sometimes more) scallops separated
by fetal clefts or "subcommissures."
[0006] During systolic contraction of the heart, the free margins
of the mitral leaflets appose each other and close the respective
atrial-ventricular passage. The chordae tendineae and papillary
muscles hold the leaflets in this position throughout the systole
cycle to prevent the leaflets from bulging into and opening within
the left atrium. The functional competence of the mitral valve
relies on proper, coordinated interaction of the mitral annulus and
leaflets, chordae tendineae, papillary muscles, left atrium, and
left ventricle. However, when the valve or its leaflets are
misshapen or enlarged, for example, when the annulus is dilated,
the edges of the leaflets fail to meet each other, leaving an
opening therebetween. This opening may involve lateral separation
of the valve leaflets and/or elevation of one valve leaflet with
respect to the other. In either case, the ineffective closure of
the valve during ventricular contraction results in regurgitation
or leakage of blood back into the atrium, and ultimately in reduced
pumping efficiency. To compensate for such inefficiency in the
mitral valve, the left ventricle must work harder to maintain the
requisite cardiac output. Over time, this compensatory mechanism
typically results in hypertrophy of the heart followed by dilation,
i.e., an enlarged heart, which can lead to congestive heart
failure.
[0007] Mitral regurgitation is one of the most common valvular
malfunctions in the adult population, and typically involves the
elongation or dilation of the posterior two-thirds of the mitral
valve annulus, the section corresponding to the posterior leaflet.
The most common etiology of systolic mitral regurgitation in
patients undergoing surgical evaluation is myxomatous degeneration,
also termed mitral valve prolapse (29% to 70% of cases), or in
gross terms, at least 5 to 10 percent of the population in the U.S.
Women are affected about twice as often as men. Mitral valve
prolapse has been diagnosed as Barlow's syndrome, billowing or
balloon mitral valve, floppy mitral valve, floppy-valve syndrome,
myxomatous mitral valve, prolapsing mitral leaflet syndrome, or
systolic click-murmur syndrome. The syndrome of mitral valve
prolapse includes palpitations, chest pain, syncope or dyspnea, and
a mid-systolic click (with or without a late systolic murmur of
mitral regurgitation). These latter findings are typically seen in
patients with Barlow's syndrome, where extensive hooding and
billowing of both leaflets are the rule. Some forms of mitral valve
prolapse seem to be hereditary, though the condition has been
associated with Marfan's syndrome, Grave's disease, and other
disorders.
[0008] Myxomatous degeneration involves weakness in the leaflet
structure, leading to thinning of the tissue and loss of
coaptation. Barlow's disease is characterized by myxoid
degeneration and appears early in life, often before the age of
fifty. In Barlow's disease, one or both leaflets of the mitral
valve protrude into the left atrium during the systolic phase of
ventricular contraction. The valve leaflets are thick with
considerable excess tissue, producing an undulating pattern at the
free edges of the leaflets. The chordae are thickened, elongated
and may be ruptured. Papillary muscles are also occasionally
elongated. The annulus is dilated and sometimes calcified. Of
course, some of these symptoms present in other pathologies, and
therefore the present application will refer to mitral valve
prolapse as a catch-all for the various diagnoses, including
Barlow's syndrome.
[0009] Other causes of mitral regurgitation include ischemic heart
disease with ischemic mitral regurgitation (IMR), dilated
cardiomyopathy (in which the term "functional mitral regurgitation"
[FMR] is used), rheumatic valve disease, mitral annular
calcification, infective endocarditis, idiopathic chordal rupture
(usually associated with fibroelastic deficiency [FED]), congenital
anomalies, endocardial fibrosis, and collagen-vascular disorders.
IMR is a specific subset of FMR, but both are usually associated
with morphologically normal mitral leaflets.
[0010] It will therefore be apparent that the types of valve
disease that lead to regurgitation are varied and present vastly
differently. For instance, FIGS. 1-8 show first a normal mitral
valve anatomy and then the causes of pure mitral regurgitation from
a number of pathologies. FIGS. 1A-1B show a normal mitral anatomy
with the mitral leaflet 20 spread out plat in FIG. 1A, and FIG. 1B
shown as a section through one papillary muscle 22. The chordae 24
connect the lower edges of the leaflet 20 to the papillary muscles
22 within the left ventricle.
[0011] FIGS. 2A-2B illustrate a condition diagnosed as infective
endocarditis, either active or healed. Vegetation or growths 30 may
occur on the leaflet 20, and sometimes a perforation 32. Often the
chordae 24 rupture, such as at 34.
[0012] FIGS. 3A-3B illustrate floppy mitral valve which causes
prolapse. The leaflets 20 is distended, increasing the annulus
area, leaflet area, and causing buckling. FIGS. 4A-4B show advanced
floppy mitral valve which causes the chordae to rupture, such as
seen at 40.
[0013] FIGS. 5A-5B illustrate rheumatic heart disease. Diffuse
fibrous thickening forms at the lower edge of the mitral leaflet 20
and the chordae 24 exhibit focal thickening.
[0014] FIGS. 6A-6B illustrate papillary muscle dysfunction
(coronary), in which one or more of the muscles is scarred and
atrophied, such as at 50. Possible effects may be severe coronary
artery narrowing and acute or healed infarct.
[0015] FIGS. 7A-7B illustrate papillary muscle dysfunction
(infiltrative), in which typically both muscles are infiltrated
with foreign bodies, possibly amyloid, sarcoid, infection or
neoplasm.
[0016] Finally, FIGS. 8A-8B annular calcification. Calcific
deposits 60 produce leaflet protrusion toward the atrium.
[0017] As is clear from the illustrations 2-8, many conditions lead
to regurgitation. However, it is understood that four general types
of structural changes of the mitral valve apparatus may produce
regurgitation: leaflet retraction from fibrosis and calcification,
annular dilation, chordal abnormalities (including rupture,
elongation, shortening, or apical tethering or "tenting" as seen in
FMR and IMR), and possibly papillary muscle dysfunction.
[0018] Carpentier's functional classification of the types of
leaflet and chordal motion associated with mitral regurgitation may
be seen with reference to FIGS. 9A-9D. In Type I, FIG. 9A, the
leaflet motion is normal. Type II (seen in FIG. 9B) mitral
regurgitation is due to leaflet prolapse or excessive motion. Type
III (restricted leaflet motion) is subdivided into restriction
during diastole Type IIIa (FIG. 9C) or systole Type IIIb (FIG. 9D).
Type IIIb (FIG. 9C) is typically seen in patients with ischemic
mitral regurgitation. The course of the leaflets during the cardiac
cycle is represented by the dotted lines. (Derived from Carpentier
A: Cardiac valve surgery: the "French correction." J Thorac
Cardiovasc Surg 86: 323, 1983.)
[0019] Various surgical techniques may be used to repair diseased
or damaged mitral and tricuspid valves. These include but are not
limited to annuloplasty (i.e., contracting the valve annulus to
restore the proper size and shape of the valve), quadrangular
resection of the leaflets (i.e., removing tissue from enlarged or
misshapen leaflets), commissurotomy (i.e., cutting the valve
commissures to separate the valve leaflets), shortening and
transposition of the chordae tendoneae, reattachment of severed
chordae tendoneae or papillary muscle tissue, and decalcification
of valve and annulus tissue.
[0020] In patients with degenerative mitral valve disease, valve
repairs using mitral valvuloplasty valve reconstruction, or
annuloplasty have been the standards for surgical correction of
mitral regurgitation and have provided good long-term results. A
rigid support ring (e.g., Carpentier-Edwards Classic.RTM.), a
semi-flexible ring (e.g., Carpentier-Edwards Physio.RTM.), or a
flexible ring (e.g., Cosgrove-Edwards.RTM.) may be used. These
rings are typically D-shaped with a minor/major axis ratio of about
3:4. Some rings are flat or planar, while others exhibit
three-dimensional bows, typically along the anterior segment. Not
all physicians agree which ring is appropriate for any one
condition.
[0021] Despite accepted treatments for correcting mitral
regurgitation, there is a need for a simpler and more effective
approach that takes into account more of the common
pathologies.
SUMMARY OF THE INVENTION
[0022] The present invention provides, in one aspect, a set of
mitral annuloplasty rings each comprising a ring body arranged
around a flow axis having an upward direction and a downward
direction. The downward direction corresponds to the direction of
blood flow through the mitral valve annulus when the annuloplasty
ring is implanted. In accordance with a preferred embodiment, the
ring body defines a minor axis extending between and bisecting the
anterior segment and posterior portion and a major axis extending
perpendicularly thereto, the major and minor axes being generally
perpendicular to the flow axis and each having dimensions across
the ring body.
[0023] The set of rings is progressively sized to take into account
more of the common pathologies. More specifically, the proportional
shapes of each ring as the orifice size changes are not the same.
In a preferred embodiment, the larger rings have larger minor axis
dimensions relative to their major axes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Features and advantages of the present invention will become
appreciated as the same become better understood with reference to
the specification, claims, and appended drawings wherein:
[0025] FIG. 1A is a diagram of a normal mitral annulus, leaflets,
and connected chordae and papillary muscles shown laid flat or
unrolled;
[0026] FIG. 1B is a "radial" sectional view through one of the
papillary muscles of FIG. 1A
[0027] FIGS. 2-8 are diagrams from the same viewpoints as FIGS. 1A
and 1B demonstrating various causes of pure mitral regurgitation as
follows:
[0028] FIGS. 2A-2B illustrate infective endocarditis;
[0029] FIGS. 3A-3B illustrate floppy mitral valve;
[0030] FIGS. 4A-4B illustrate floppy mitral valve with ruptured
chordae;
[0031] FIGS. 5A-5B illustrate rheumatic heart disease;
[0032] FIGS. 6A-6B illustrate papillary muscle dysfunction
(coronary);
[0033] FIGS. 7A-7B illustrate papillary muscle dysfunction
(infiltrative); and
[0034] FIGS. 8A-8B illustrate annular calcification;
[0035] FIGS. 9A-9D illustrate Carpentier's functional
classification of mitral regurgitation, namely: Type I: normal
leaflet motion. Type II: increased leaflet motion (leaflet
prolapse). Type III: restricted leaflet motion; IIIa, restriction
in diastole and systole; IIIb, restriction in systole;
[0036] FIGS. 10 and 11 are plan and section views of an exemplary
annuloplasty ring of the present invention;
[0037] FIG. 12 is a graph showing the changing minor/major axis
proportion of the exemplary ring; and
[0038] FIGS. 13-18 show plan and side views of several different
sized rings of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] The present invention provides a novel set of annuloplasty
rings for correcting pathologies resulting in mitral
regurgitation.
[0040] FIGS. 10 and 11 are plan and section views of an exemplary
annuloplasty ring 70 of the present invention. The ring 70 is shown
with a fabric covering 72 over a structural interior support or
body 74. Typically a suture-permeable interface 76 fills the space
between the covering 72 and interior body 74.
[0041] The ring 70 in the plan view of FIG. 10 has a minor axis
dimension B and a major axis dimension A. FIG. 11 shows preferred
heights above a datum plane, with the center of the anterior
segment rising to height C and the center of the posterior segment
rising to height D. The preferred ratio of C/D is about 3:1, with
the smallest rings rising to 3 mm on the anterior side and the
largest to about 6 mm.
[0042] The interior body 74 of the present invention in one
embodiments is desirably made of material(s) that are "generally
rigid" and will initially resist distortion when subjected to the
stress imparted thereon by the mitral valve annulus of an operating
human heart. In this sense, "distortion" means substantial
permanent deformation from a predetermined or manufactured shape;
the opposite concept of which is "elastic" meaning the ability to
recover the ring shape in the absence of an external force. A
number of "generally rigid" materials can be utilized that will
perform this function, including various bio-compatible polymers
and metals and/or alloys. Certain polyesters that resist distortion
and also rapid degradation within the body may be used (a material
that degrades slowly may provide the required initial support). In
a preferred embodiment, at least an inner core or body of the
annuloplasty ring of the present invention is made of a suitable
metal, such as titanium or its alloys, or ELGILOY made by Elgiloy,
L. P. of Elgin, Ill., U.S.A. The core or ring body may be one
piece, or may include a plurality of concentric or otherwise
cooperating elements.
[0043] The interface 76 is a molded silicone tube or band around
the ring body 74 and the fabric covering on the exterior of the
ring is desirably Dacron (polyethylene terephthalate). The tubular
fabric covering around the silicone sleeve provide an interface for
securing the annuloplasty ring to the mitral annulus, although
other interfaces are contemplated. For example, rings having
outward hooks or barbs are known in the art.
[0044] Typical annuloplasty support rings have a long or major
dimension and a short or minor dimension, with the conventional
ratio of the minor to major dimension being at most 3:4 (75%), and
typically less. The present invention provides an annuloplasty ring
that has a gradually increasing minor axis dimension B to major
axis dimension A ratio. The dimensions A and B are measured to the
inner edge of the body 74. This increasing dimensional ratio
provides rings in the larger sizes that are more suited to
correcting conditions where the mitral leaflet is floppy, such as
the conditions shown in FIGS. 2-4, and in general for Type II
pathologies seen in FIG. 9B. Typically, larger patients exhibit
this general condition leading to regurgitation as opposed to
smaller patients, for which rings having more conventional B/A
ratios are more appropriate.
[0045] The following table indicates the actual values of the major
and minor axes as measured across the interior of the ring body 74
(dimensions A and B, respectively, in FIG. 10) for nine different
exemplary rings, and also gives the ratios of the minor axis to the
major axis. The ring sizes are given in even 2 mm increments as
measured across the major axis. Such rings will have distinct
packaging so as to be labeled with the particular size.
TABLE-US-00001 Major axis Minor Axis Ring size (mm) (mm) (mm) B/A
ratio 24 24.0 16.5 0.6875 26 26.0 17.7 0.6808 28 28.0 18.9 0.6750
30 30.0 20.4 0.6800 32 32.0 21.9 0.6844 34 34.0 23.5 0.6912 36 36.0
25.5 0.7083 38 38.0 28.5 0.7500 40 40.0 32.0 0.8000
[0046] FIG. 12 is a graph showing the changing minor/major axis
proportion of the exemplary ring along line 80 as compared with a
line 82 for a prior art ring, the Carpentier-Edwards Physio.RTM.
ring. This shows the divergence of the ring proportions starting at
around the 32 mm ring.
[0047] FIGS. 13-18 show plan and side views of several different
sized rings of the present invention for comparison. FIGS. 13-14
show a 24 mm ring, FIGS. 15-16 show a 32 mm ring, and FIGS. 17-18
show a 40 mm ring. The overall "look" of the rings are the same
though the B/A ration increases in the larger rings.
[0048] While the invention has been described in its preferred
embodiments, it is to be understood that the words which have been
used are words of description and not of limitation. Therefore,
changes may be made within the appended claims without departing
from the true scope of the invention.
* * * * *