Apparatus and method for reducing and stabilizing the circumference of a vascular structure

An apparatus and method for reducing the circumference of a vascular structure comprising the steps of providing a plurality of sutures and a plurality of discrete suture support segments of a biocompatible, inert material, each suture support segment having at least two suture holes spaced a predetermined distance (D) apart; individually suturing each discrete suture support segment to the vascular structure with one of the plurality of sutures by effecting a horizontal mattress (U-shaped) suture along the vascular structure through a length of tissue of the vascular structure such that the length (D') of tissue sutured is greater than distance (D); and tightening and tying off the suture, whereby each sutured suture support segment creates an imbrication in the vascular structure, thereby reducing the circumference thereof. A biocompatible, inert stabilizing material may optionally be affixed over the suture support segments and the vascular structure after prior to tying off the suture to stabilize the interval between the suture support segments and eliminate direct exposure of the segmented apparatus to blood.

BACKGROUND OF THE INVENTION 
The present invention relates generally to an apparatus and method for 
reducing the circumference of a vessel, and more particularly to an 
apparatus and method for reducing the circumference of vascular 
structures, including cardiac valves. 
All artificial or prosthetic heart valves, whether mechanical or 
bioprosthesis, although greatly improving the condition of the patient, 
have some serious drawbacks; namely thrombogenicity (tendency towards 
thrombus formation and subsequent detachment with embolization), and 
limited durability secondary to tissue structure failure. 
Other complications such as noise, interference with hemodynamics, 
especially in smaller sizes, hemolysis (destruction of blood elements), 
risk of thromboembolism in all patients who receive mechanical valves, 
endocarditis (valve infection) and dehiscence of the valve also occur. 
Because of the risk of embolism, the majority of patients who receive 
artificial heart valves need to take anticoagulative medication for life 
with the concomitant risk of hemorrhage and necessary change in life 
style. 
Different and more recent developments in the field of cardiac surgery 
included attempts to surgically repair diseased vascular tissue, in 
particular, heart valves. A variety of surgical maneuvers or procedures 
have been used for this purpose. This type of reconstructive surgery has 
been shown to be superior to valve replacement in many respects. 
Reconstructive surgery, however, is generally more difficult to perform 
than replacement and is not always possible in every patient. Among the 
variety of reconstructive maneuvers, valve annuloplasty is the most 
frequently performed in the tricuspid and mitral valves. Valve 
annuloplasty is an operation which selectively reduces the size of the 
valve annulus. For this purpose, a number of prosthetic rings have been 
developed for the atrioventricular valves. One such well known 
commercially available ring is the Carpentier (distributed by American 
Edwards Laboratories) ring. 
The Carpentier method of valvuloplasty employing the Carpentier ring is 
disclosed in the product pamphlet "Prosthetic Rings and Accessories for 
Tricuspid and Mitral Valvuloplasty", produced by American Edwards 
Laboratories in December, 1985. 
Carpentier et al., U.S. Pat. No. 5,061,277 relates to a flexible cardiac 
valvular support prosthesis which is generally ring shaped and has a first 
length which is flexible and a second length which is less flexible than 
the first length, so the support may shape the annulus while the first 
length of the support in place in a heart valve annulus allows contraction 
thereof. 
Carpentier et al., U.S. Pat. No. 4,917,698 relates to a multi-segmented 
annuloplasty ring prosthesis for use in the surgical correction of a 
deformed heart valve, which provides a substantially circular body 
comprising in part segments joined together by flexible joints, the body 
being shaped in proportion to the annulus of a heart valve. 
Duran, U.S. Pat. No. 5,258,021 relates to a Sigmoid Valve Annuloplasty Ring 
in a scalloped shape having three sinusoidal struts to adapt to the 
anatomical shape of the annulus of the human sigmoid valves. The ring is 
made of a biocompatible material covered with a biocompatible cloth. 
Lam et al., U.S. Pat. No. 5,104,407 relates to a selectively flexible 
annuloplasty ring for suturing to the annulus of a heart valve, the 
annular ring comprising a partially flexible length and a partially rigid 
length. The ring is covered in a suturable material. 
Wright et al., U.S. Pat. No. 5,201,880 relates to Mitral and Tricuspid 
Annuloplasty Rings having a unitary construction with internal drawstrings 
and a semi-flexible stiffener in the anterior segment. 
Cosgrove et al., U.S. Pat. No. 5,041,130 relates to an assembly for holding 
a substantially flexible lenticular shaped annuloplasty ring in a position 
for suturing about a valve annulus. The unitary annuloplasty ring 
contemplated therein is substantially flexible, and is partially 
circumferential, encompassing only the posterior mitral annulus. 
Reed, U.S. Pat. No. 4,489,446 relates to an adjustable heart valve 
prosthesis with unitary construction including a dynamic stiffener 
element. 
Gilbertson et al., U.S. Pat. No. 5,064,431 relates to an annuloplasty ring 
of tubular construction including drawstrings selectively adjustable to 
adjust the annulus to a desired shape. 
Myers et al. U.S. Pat. No. 5,011,481 relates to a holder for an 
annuloplasty ring for use in implantation. 
Commercially available annuloplasty rings have several drawbacks. First, 
they are expensive. Second, unless they are either rigid or sutured to the 
tissue annulus while still attached to a rigid holder, they may not 
provide a precise, predictable reproducible annuloplasty because of the 
unpredictable degree of longitudinal shortening along the circumference of 
the sutures within the confines of each mattress suture used to secure the 
ring to the tissue annulus. Each suture is necessarily tied with variable 
and unpredictable degrees of tension by the operating surgeon. 
Third, most mitral rings are completely circumferential committing the 
operating surgeon to placing sutures in the anterior annulus where 
dilatation rarely occurs and where a tissue tear from inexact suture 
placement can produce significant mitral regurgitation. Fourth, a rigid 
mitral ring, because it is preshaped to an oval configuration, must be 
precisely placed or an unsatisfactory annuloplasty may result. Fifth, a 
rigid tricuspid ring can dehisce if not made to conform to the slightly 
spiral, nonplanar shape of the tissue annulus. Sixth, any rigid ring 
prevents the normal flexibility of the tissue annulus of the 
atrioventricular valve during ventricular contraction. 
A need exists for an apparatus and method which provides a customized 
annuloplasty, tailored to the needs of specific pathophysiological 
situations, including but not limited to a limited annuloplasty or 
commissuroplasty of any valve annulus, a subtotal annuloplasty of any 
valve or a complete annuloplasty of any valve annulus. A need also exists 
for an apparatus and method which allows the repaired vascular structure 
to retain its flexibility in all planes while preventing further 
dilatation, or circumferential lengthening of the tissue annulus or 
vascular structure. 
It has been found that to achieve such objects, a commercially available 
annuloplasty ring is not necessary. Such objects may be effected through 
use and implantation of an annuloplasty device comprising a series of 
discrete suture support segments. 
SUMMARY OF THE INVENTION 
The basic and general object of the present invention is to provide a 
method and apparatus that maintains the normal shape of a vessel or 
induces the vessel to regain its normal shape. 
More specifically, when performing a valve annuloplasty, the object of the 
present invention is to implant a device which reduces the circumference 
of a diseased cardiac valve annulus or vascular structure to the desired 
size. Specifically, repositioning of displaced and incompetent valvular 
cusps and commissures or reduction and remodeling of annular or vascular 
dilatation by precisely defined plications (tucks or folds) at specified 
points is effected. 
The inventive method of reducing the circumference of a vascular structure 
having an upper portion and a lower portion, said upper and lower portions 
of the vascular structure defining an upper circumference and a lower 
circumference of said vascular structure, comprises the steps of: 
a) providing a plurality of discrete suture support segments of a 
biocompatible inert material, each suture support segment further 
comprising an upper surface, a lower surface, opposite sides, a proximal 
end, a distal end and at least two suture holes extending from the upper 
surface to the lower surface thereof and being spaced a predetermined 
distance (D) apart; 
b) providing a suture; 
c) individually suturing each suture support segment to the vascular 
structure whose circumference is to be reduced by means of a horizontal 
mattress (U-shaped) suture along the vascular structure through a length 
of tissue of the vascular structure such that the length (D') of tissue 
sutured is greater than distance (D); and 
d) tightening and tying off the suture, 
whereby each sutured segment creates an imbrication in the vascular 
structure, thereby reducing the circumference thereof by an amount equal 
to (D')-(D). 
Alternatively, the method may comprise the further step of affixing a 
biocompatible, inert stabilizing material over the suture support segments 
and the vascular structure by means of horizontal mattress sutures through 
each suture support segment and through the tissue of the vascular 
structure, said stabilizing material being of predetermined dimensions 
sufficient to cover the suture support segments affixed to the vascular 
structure, thereby stabilizing the interval between the suture support 
segments in order to prevent further lengthening of the vascular 
structure, and eliminating direct exposure of the suture support segments 
to blood.

DETAILED DESCRIPTION OF THE INVENTION 
While this invention may be embodied in many different forms, there are 
described in detail herein specific preferred embodiments of the 
invention. This description is an exemplification of the principles of the 
invention and is not intended to limit the invention to the particular 
embodiments illustrated. 
The present invention provides an apparatus and method for reducing the 
circumference of a vascular structure. The present invention also provides 
an apparatus and method for permanently reconstructing a vascular 
structure to a normal configuration, to restore its original form and 
function. The apparatus comprises a plurality of suture support segments 
like that shown generally at 10 in FIG. 1, sutured to a vascular 
structure. A plurality of suture support segments is shown in place 
generally at 100 in FIG. 4. As shown in FIG. 1, each individual suture 
support segment 10 comprises an upper surface 12, a lower surface 14, 
opposite sides 16, 18, a proximal end 20, and a distal end 22. Each suture 
support segment 10 has exactly two suture holes. The embodiment shown at 
FIG. 1 has a first suture hole 24 and a second suture hole 26 extending 
from upper surface 12 to lower surface 14, spaced a predetermined distance 
(D) apart. Suture holes 24, 26 should be large enough to accommodate a 2-0 
suture and swedged-on needle. In addition, suture holes 24, 26 should be 
smooth in order to prevent suture fraying or cutting when suture 60 is 
tied. The distance (D) between suture holes 24, 26 may be varied, although 
an interval of 5 mm (.+-.3 mm) from center to center of holes 24, 26 is 
suitable. 
Although any suitable suture may be used, the most preferred as shown in 
the figures has a swedged-on surgical needle at each end thereof. 
Alternatively, a single needle suture may be used. 
Suture support segment 10 may be made of any suitable material which is 
biocompatible with blood and tissue, inert, non-corrosive and 
non-thrombogenic. As a practical matter, the material of which suture 
support segment 10 is made should be a substance already approved for 
intra-vascular use by the FDA such as titanium. Suture support segment 10 
must be rigid or semi-rigid in the longitudinal dimension, and must not be 
deformable, so that it does not buckle when suture 60 is tied. 
Although suture support segment 10 may be of any suitable shape, the 
spatulated shape shown in FIG. 1 is quite effective. The minimum dimension 
from outside edge of suture hole to the end of suture support segment 10 
in order to minimize the chance of abutment or overlap of adjacent suture 
support segments is about 1 mm. The minimum width to minimize mass but not 
to allow cutting into tissue is between about 2 mm-4 mm. The minimum 
thickness to reduce mass but avoid buckling of suture support segment 10 
is about 1 mm. 
The method of reducing the circumference of vascular structure is shown at 
FIGS. 2-6. As shown at FIG. 2, vascular structure 50 has an upper portion 
52 and a lower portion 54, said upper and lower portions 52, 54 defining 
an upper circumference and a lower circumference of vascular structure 50. 
Apparatus 100 comprising a plurality of suture support segments 10. Suture 
support segments 10 are individually affixed to vascular structure 50 
whose circumference is to be reduced, by means of a horizontal mattress 
(U-shaped) suture 60 along vascular structure 50 through a length of 
tissue of vascular structure 50. Referring to FIG. 2, the suture 60 
traverses a longer distance along vascular structure 50 than the distance 
(D) between suture holes 24, 26 of suture support segment 10. 
Specifically, the length or distance (D') between the entry and exit of 
suture 60 is greater than distance (D) between suture holes 24, 26 of 
suture support segment 10. As shown in FIGS. 2 and 3, both ends of suture 
60 are brought up through suture holes 24, 26 of suture support segment 
10. The length (D') of tissue of vascular structure 50 sutured is greater 
than distance (D), whereby each sutured segment 10 creates an imbrication, 
or tuck 62, in vascular structure 50, thereby reducing the circumference 
thereof. 
Sutures 60, when tied, will reduce the circumference of a vascular 
structure by an amount equal to (D')-(D), the difference between the 
length (D') each individual mattress suture 60 travels in the tissue of 
vascular structure 50 and the distance (D) between the 2 suture holes 24, 
26 in the individual suture support segment 10. In other words, vascular 
structure 50 is imbricated underneath suture support segment 10, within 
the individual mattress suture, by a precise amount depending on the 
linear distance (D') along the tissue of vascular structure 50 which the 
individual suture 60 travels. 
A plurality of suture support segments 10 in place is shown at FIG. 4. 
Referring to FIG. 5, a biocompatible, inert stabilizing material 70 may 
optionally be provided. As shown, stabilizing material 70 is also affixed 
over the segmented apparatus and the vascular structure by means of 
horizontal mattress sutures 60 through each segment and through the tissue 
of vascular structure 50. Stabilizing material 70 may be affixed to 
vascular structure 50 by means of the same sutures 60 used to affix 
segments 10 thereto. Both ends of suture 60 are brought up through 
stabilizing material 70 prior to tying of suture 60. 
Alternatively, the stabilizing material and suture support segment may be 
sutured to vascular structure 50 with one continuous suture using a single 
needle. The mattress suture would be effected by passing the needle and 
suture first through the stabilizing material from an entry point in the 
upper surface thereof through the lower surface thereof, then through a 
suture hole in the suture support segment, suturing the length of tissue 
of the vascular structure, passing the suture through a second suture hole 
in the suture support segment, passing the suture through the stabilizing 
material from the lower surface thereof and out an exit point in the upper 
surface thereof. The suture would then be tightened and tied off such that 
the suture knot formed would sit on the upper surface of the stabilizing 
material. Alternatively, a running mattress suture would be possible by 
tying a single suture to itself or to an additional suture or by repeating 
the course of the running mattress suture in reverse. 
Stabilizing material 70 is of predetermined dimensions sufficient to cover 
apparatus 100 affixed to vascular structure 50, and may actually be 
another layer of tissue such as autologous, homologous or heterologous 
pericardium, or alternatively may be made of any suitable fabric, such as 
dacron. 
Stabilizing material 70, shown in place in FIG. 6, stabilizes the interval 
between sutures 60, preventing further dilatation or circumferential 
lengthening of the tissue annulus or vascular structure between sutures. 
The stabilizing material 70 also eliminates direct exposure of the 
segmented apparatus 100 to blood. 
The practice of the present invention achieves several objectives and 
advantages. The objectives and advantages are as follows. 
The segmented apparatus of the present invention is much less expensive to 
produce than commercial annuloplasty rings, as it comprises discrete 
suture support segments which are economical to produce. 
The apparatus and method allows precise imbrication within each mattress 
suture supported by suture support segments. This is not possible with any 
annuloplasty device which is deformable in a longitudinal direction unless 
the device is attached to a rigid holder while the sutures are tied. The 
present apparatus and method allows for an absolutely precise, predictable 
and reproducible annuloplasty. 
The inventive apparatus and method provide construction of a customized 
annuloplasty, not possible with commercial annuloplasty rings. A limited 
annuloplasty or commissuroplasty of any valve annulus, as shown in FIGS. 
8, 10 and 11 can be performed, as can a posterior mitral valve 
annuloplasty as shown in FIGS. 4 and 6, as well as a subtotal annuloplasty 
of any valve such as the tricuspid valve, as shown in FIG. 9, or a 
complete annuloplasty of any valve annulus as shown in FIG. 7. FIGS. 10 
and 11 show a commissural annuloplasty of a semilunar valve. FIGS. 12, 13 
and 14 show a stabilizing annuloplasty of the aortic valve annulus. 
The discrete suture support segments allow flexibility of the annulus or 
vascular structure in all planes, analogous in principle to a chain-link 
fence, although the links are separate. The resulting annuloplasty is more 
physiologic than with a rigid ring since it is flexible in all planes. In 
the case of the mitral and tricuspid valve annulus, systolic contraction 
is still possible. 
The present invention provides not only an annuloplasty device which is not 
only less expensive than commercially available annuloplasty rings, but 
also a more precise, predictable reproducible annuloplasty than is 
provided by any flexible ring not attached to a rigid holder while the 
sutures are tied. The discrete suture support segments make it possible to 
reduce the circumference of the valve annulus by a specific length. A 
customized annuloplasty, including but not limited to a limited 
annuloplasty or commissuroplasty of any valve annulus, a subtotal 
annuloplasty of any valve or a complete annuloplasty of any valve annulus 
may thereby be provided. 
Repair of a vascular structure with the present apparatus and method allows 
the repaired vascular structure to retain its flexibility in all planes, 
and further minimizes the possibility of dehiscence of the vascular 
structure, and the possibility of further dilatation, or circumferential 
lengthening of the vascular structure. Further, the possibility of failure 
of the present apparatus when in place at the tissue annulus is lessened 
by providing discrete suture support segments. Conversely, a rigid, 
unitary annuloplasty ring when implanted will by definition resist any 
physiological motion of the tissue annulus either downward (away from the 
lower surface of the ring) or inward (toward the orifice of the ring), and 
may therefore come out of its implanted site. 
In addition, the need for temporary anticoagulation recommended with 
commercial annuloplasty rings is probably unnecessary with the present 
invention, especially if the segmented apparatus is covered with a 
stabilizing material such as pericardium, as no thrombogenic surfaces are 
exposed to the blood except for suture knots. 
Suture knots are less likely to come untied when used in conjunction with a 
stabilizing material which is significantly deformable in a longitudinal 
direction, such as pericardium, since individual sutures can be tied 
firmly with uniform maximal tension against the non-deformable suture 
support segment without any possibility of additional longitudinal 
shortening of the tissue annulus due to excessive tension during 
knot-tying. 
When the apparatus and method of the present invention is used in infants 
and growing children without the stabilizing material, the potential for 
growth of a vascular structure or cardiac valve annulus between the suture 
support segments is retained. 
When used to perform a commissural annuloplasty of a semilunar valve, as 
shown in FIGS. 10 and 11, and the suture support segments are vertically 
oriented within the sinus on either side of the commissure just short of 
the leaflet hinge, no reduction in leaflet height occurs when the suture 
is tied. Such leaflet height reduction at the commissures could occur if 
the buttressing material were deformable (e.g. teflon felt pledget). 
A "stabilizing" annuloplasty of the aortic valve annulus could be 
accomplished in operations wherein a dilated aortic root is replaced with 
a dacron conduit and the aortic valve is spared (e.g., Yacoub and David) 
particularly if the conduit is used to create "pseudo-sinuses" and does 
not engage the actual aortic valve annulus with sutures (FIGS. 12, 13). In 
such cases the suture support segments could be placed on the endocardial 
surface of the left ventricular outflow tract in a single horizontal plane 
immediately below the lowest points of the scalloped aortic valve sinuses 
avoiding contact with the leaflet hinge. The stabilizing material could 
then be placed on the epicardial surface (FIG. 14). 
Although the present invention is particularly suited for reducing the 
circumference of vascular structures such as cardiac valves as indicated 
hereinabove, the apparatus and method may be applied to reduce the 
circumference of any valve, vessel or lumen in the body, including those 
in the digestive, genito-urinary, circulatory or respiratory systems. By 
the method described hereinabove, a plurality of suture support segments 
are sutured around a predetermined portion of the circumference of the 
structure, for example an intestinal lumen. 
The above Examples and disclosure are intended to be illustrative and not 
exhaustive. These examples and description will suggest many variations 
and alternatives to one of ordinary skill in this art. All these 
alternatives and variations are intended to be included within the scope 
of the attached claims. Those familiar with the art may recognize other 
equivalents to the specific embodiments described herein which equivalents 
are also intended to be encompassed by the claims attached hereto.