United States Patent [191
`Totten et al.
`
`[11] Patent Number:
`[45] Date of Patent:
`
`4,477,930
`Oct. 23, 1984
`
`[54]
`
`[75]
`
`[73]
`
`[21]
`[22]
`[5 l]
`[52]
`[58]
`[56]
`
`NATURAL TISSUE HEAT VALVE AND
`METHOD OF MAKING SAME
`Inventors: Robert P. Totten; Gail S. Totten, both
`of Denver, Colo.; Mary A. Wilson,
`San Jose, Calif.
`Assignee: Mitral Medical International, Inc.,
`Wheat Ridge, Colo.
`Appl. No.: 425,553
`Filed:
`Sep. 28, 1982
`
`Int. Cl.3 .............................................. .. A61F 1/22
`U.S. C1. ................................................ .. 3/1.5
`Field of Search
`.................................. .. 3/1.5, 1
`References Cited
`U.S. PATENT DOCUMENTS
`
`3,548,418 12/1970 Angell et a1. .......................... .. 3/ 1.5
`
`
`
`3,655,306 4/1972 Ross et al. 3,739,402 6/1973 Cooley et al. ......................... .. 3/ 1.5
`
`3,755,823 9/1973 Hancock ................................ .. 3/1.5
`3,983,581 10/1976 Angelletal. ..
`3/1.s
`4,035,849 7/1977 Angelletal. ..
`3/1.5
`4,084,268 4/1978 Ionesco etal. .
`3/l.5
`4,172,295 10/1979 Batten .................................... .. 3/15
`
`Primary Examiner-Ronald L. Frinks
`Attorney, Agent, or Firm-John E. Reilly
`[57]
`ABSTRACT
`A low pro?le natural tissue heart valve with a one-piece
`fabric covering is applied to a stent in a minimum num
`ber of steps so that virtually no seams are exposed. The
`one-piece covering serves also to enclose and mount the
`sewing ring to avoid separation from the stent. The
`procedure employed enables use of bovine pericardium
`united as a single piece to the exterior of the stent and
`?xed in position in such a way as to avoid prolapsing in
`use.
`
`18 Claims, 10 Drawing Figures
`
`NORRED EXHIBIT 2102 - Page 1
`Medtronic, Inc., Medtronic Vascular, Inc.,
`& Medtronic Corevalve, LLC
`v. Troy R. Norred, M.D.
`Case IPR2014-00110
`
`

`

`US. Patent Oct. 23, 1984
`
`Sheet 1 of 2
`
`4,477,930
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`1/
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`4
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`1
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`3
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`NORRED EXHIBIT 2102 - Page 2
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`

`

`US. Patent Oct. 23, 1984
`
`Sheet 2 of2
`
`4,477,930
`
`NORRED EXHIBIT 2102 - Page 3
`
`

`

`1
`
`4,477,930
`
`NATURAL TISSUE HEAT VALVE AND METHOD
`OF MAKING SAME
`
`This invention relates to tissue valves; and more par
`ticularly relates to a novel and improved, low pro?le,
`natural tissue heart valve and to the method of making
`same.
`
`5
`
`45
`
`55
`
`2
`SUMMARY OF THE INVENTION
`Among the desirable objectives and advantages of
`the present invention in the construction of natural
`tissue heart valves is the formation of a low pro?le
`valve with a one-piece fabric covering applied to a stent
`in a minimum number of steps so that no raw seams or
`edges are exposed and wherein the one-piece covering
`will serve also to enclose and mount the sewing ring in
`place so as to avoid separation of the sewing ring from
`the stent. The procedure employed further enables the
`use of a pericardium or tissue which is united as a single
`piece element to the stent in such a way as not to pro
`lapse in use.
`In carrying out the teachings of the present invention,
`a single piece of fabric is formed into a tube which is
`sized for insertion within a circular mounting frame
`having a series of circumferentially spaced commissure
`posts, the latter separated by curved depressions or
`scalloped portions above a common annular base. One
`end of the tube is folded over the posts or tips leaving
`the longer portion of the tube inside of the stent. The
`folded-over portion of the tube ‘is then stitched in
`closely surrounding relation to the posts and interven
`ing scallops, after which the excess material is trimmed
`and the tubular portions inverted or turned inside out so
`as to place the seam inside of the inner and outer tube
`portions. The stent is reinsertedlinto the scalloped tubu
`lar portion between the skirts, and the skirts are sewn
`together along the lower edge of the base of the stent
`followed by anchor stitching the outer skirt portion
`through sewing holes formed at spaced intervals within
`the body of ‘each post. The remaining lengths of the
`skirt portions extending beyond the base stitching are
`then drawn over the outside of the stent and stitched
`together along a second base line of the skirt. An elasto
`meric sewing ring is inserted between the skirts so as to
`rest against the second base line and the longer skirt
`folded over the sewing ring and secured to the stent
`followed by stitching the short skirt to the long skirt.
`The pericardium is specially selected and formed into
`a rectangular section of uniform thickness which is cut
`from a partially ?xed pericardial sac. The rectangular
`section is secured to the base of the stent directly above
`the sewing ring with the ?brous outer layer of pericar
`dium oriented to the in?ow aspect or direction and with
`the abutting edges of the rectangular section located
`midway along one of the commissure posts. A continu
`ous suture line is employed to secure the edge of the
`rectangular section to the base of the stent covering
`with knots formed at each of the commissure posts
`which are then hidden in pockets formed at the time of
`stent covering. A continous criss-cross suture line is
`then formed along each of the posts to secure the tissue
`thereto while leaving equal amounts of tissue in the
`depressions or scalloped portions between each of the
`posts for the formation of the cusps. Fixation of the
`tissue is carried out with the valves placed on a lea?et
`form mandrel and immersing in a bath of tissue ?xative
`after which any ?nal trimming is carried out.
`Other objects, advantages and features of the present
`invention will become more readily appreciated and
`understood when taken together with the following
`detailed description in conjunction with the accompa
`nying drawings, in which:
`
`BACKGROUND AND FIELD OF THE
`INVENTION
`This invention is directed to certain improvements in
`the construction and method of fabrication of natural
`tissue heart valves of the type characterized by having
`a cloth or fabric covered stent which incorporates a
`suture ring at its base so as to facilitate its implantation
`into the annulus or wall of the heart using conventional
`surgical procedures. The valve element itself is com
`posed of pericardium which is mounted upon and sewn
`20
`to the stent and, for example, in a semicircular heart
`valve is so con?gured as to de?ne three cusps which
`will undergo opening and closing in response to rever
`sals in the ?ow of blood through the annulus.
`In the construction of natural tissue heart valves, it is
`25
`important that the valve have a low pro?le and speci?- ,
`cally that the tissue valve support posts on the stent be
`as short as possible so as to avoid rupture of the ventric
`ular wall. Low pro?le porcine valves have been devised
`but have not been found to possess the optimum hydro
`dynamic characteristics desirable in a tissue valve. Bo
`vine pericardium has been employed in the past as the
`tissue valve for enhanced hydrodynamic performance
`but has been placed along the interior of the stent in
`order to effect the necessary support of the valve. A
`35
`greater effective ori?ce area can be achieved. if the
`bovine pericardium can be supported around the exte
`rior of the stent and fabric covering while avoiding the
`necessity of making the stent unduly rigid or in?exible;
`and further if the necessary stitching or anchoring of 40
`the tissue or pericardium be performed between the
`tissue and exterior of the stent so that the lea?ets can
`open as wide as possible while leaving a smooth interior
`thereby'achieving a lower pressure drop. Thus, a close
`' ly-related consideration in the construction of the valve
`is that the stitching employed between the cloth cover
`ing, stent, sewing ring and tissue be uniform or symmet
`rical throughout and in such a way as to avoid the intro
`duction of increased bulk or non-uniformities in thick
`ness at any point as well as to eliminate any exposed
`seams or fabric edges. Achievement of the foregoing
`will then permit utilization of a single piece of tissue as
`the valve element which can be securely mounted in
`place onto the cloth-covered stent while maintaining a
`uniform internal diameter when the tissue valve element
`is expanded to its open position.
`Previously, it has been the practice to employ pres
`sure ?xation in the pre-forming of the tissue valve ele
`ment. However, it is desirable to avoid pressure ?xation
`so as not to affect the collagen bundles in the vtissue and
`in general to provide for an improved method of ?xa~
`tion of the tissue valve element with respect to the
`cloth-covered stent.
`Representative patents of interest in the fabrication
`and construction of natural tissue heart valves are U.S.
`Pat. Nos. 3,548,418, 3,983,581 and 4,035,849 to W. W.
`Angell et al; 4,084,268 to M. I. Ionescu et a]; and
`4,172,295 to R. J. Batten.
`
`60
`
`65
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`NORRED EXHIBIT 2102 - Page 4
`
`

`

`3
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a somewhat isometric view illustrating the
`- ?rst step in the fabrication of a natural tissue heart valve
`in which a fabric tube is inserted within a circular stent
`
`or frame;
`
`,
`
`Y
`
`'
`
`FIG. 2 is an isometric view illustrating the seam
`which is formed between the fabric tube and scalloped
`edge of the stent;
`FIG. 3 is an isometric view showing the folded-over
`portions of the tube inverted so as to place the seam
`along the scalloped edges inside followed by anchor
`stitching of the tube to the base of the stent;
`‘FIG. 4 is an enlarged fragmentary view illustrating
`the stitching of the fabric to a post;
`FIG. 5 is an isometric view with the stent inverted
`and showing the stitching of a second base line between
`the outer skirt portion of the tube and the base of the
`stent;
`.
`FIG. 6 is a view illustrating the?rst step in the an
`choring of the sewing ring to the base of the stent; '
`. FIG. 7 is an isometric view of the completed fabric
`covering and stent; _
`FIG. 8 is an enlarged cross-sectional view illustrating
`in more detail the anchoring of the sewing ring in place
`through the stent and skirt portions of the tube;
`FIG. 9 is an isometric view in elevation of the form
`ing tool employed in the mounting of the tissue into the
`desired con?guration with respect to the stent; and‘
`FIG. 10 is an isometric view of a preferred form of
`30
`natural tissue valve formed in accordance with the pres
`ent invention.
`
`4,477,930
`4
`.
`in FIG. 10. As noted from FIG. 10, in the relaxed state
`the cusps are closed together along their downstream
`edges 26. However, in response to the ?ow of blood
`through the annulus the cusps will expand substantially
`beyond the full diameter of the stent 12, then under
`reversal in the flow of blood will return to their relaxed
`or closed state.
`A sewing ring 28 is positioned in outer surrounding
`relation to the base of the stent and in a manner to be
`described is integrated into the valve by the fabric cov
`ering so as to serve as a secure means of implantation.
`The ring 28.may be composed of cloth, e.g., felt or a
`compliant elastomer, e.g., silicone elastomer which,
`upon grafting or implantation, will together with the
`covering 14, form a suitable base for ?brous ingrowth;
`also, the ring is suf?ciently pliable as to conform to
`irregular openings but will assure a snug ?t and seal
`with the wall of the annulus to which it is secured.
`In the fabrication of the preferred form of tissue
`'valve, the sequence of steps followed is illustrated in
`20
`FIGS. 1 to 9 in accordance with the present invention.
`vAs illustrated in FIG. 1, a strip of bias cut fabric in the
`form of a parallelogram is con?gured into a tube 30 by
`sewing the raw edges together to form a bias seam 31
`and the tube then inserted in close ?tting relation within
`the stent 12 with the longer portion of the tube extend
`ing downwardly beyond the base of the stent. As seen
`from FIG. 2, the upper portion of the tube 30 is folded
`over the stent and overlaps the lower portion of the
`tube for a limited distance beyond the base so as to
`result in a relatively short skirt portion 32 and a longer
`skirt portion 33 on opposite sides of the stent. The skirt
`portions are basted together as at B'along a circumfer
`DETAILED DESCRIPTION OF THE
`ential line extending directly beneath the lower edge of
`PREFERRED EMBODIMENT
`the stent with the upper tip portions 21 of ‘the commis
`' sure post 19 bearing snugly against the folded edge of
`Referring in more detail to the drawings, there is
`' the fabric tube. The fabric layers are then stitched along
`illustrated in FIGS. 1 to 10 a preferred form of heart
`the posts 19 and scalloped edges 20 according to the
`valve 10 which is broadly comprised of a stent 12, fabric
`-.procedure.illustrated in FIGS. 3 and 4 wherein lock
`covering 14 and pericardial tissue valve element 16. As
`knots k are formed on opposite sides of each tip, then
`shown in FIG. 1, the stent 12 is made up of an annular
`40
`‘drawn together so as to snugly embrace opposite sides
`' base 18 with three circumferentially spaced commissure
`of each tip 21. Speci?cally, each lock knot k is formed
`posts 19 which project in a common direction at, equally
`by passing the thread through the fabric layers on one
`spaced circumferential intervals from the ‘base and are
`side of thetip as at point a and looping the suture or
`, separated by scallops or curved depressions 20'..Pre_fera
`thread back over the frontal surface of the tip and re
`bly, the stent is composed of a plastic material possessf
`turning it through the fabric layers at point b directly
`ing limited resiliency such that the commissure posts 19
`beneath point. a and then advancing through the loop
`p are capable of undergoing inward and outward ?exing
`formed between a and b and ‘continuing as at 0 over to
`in following the movement of the tissue valve element
`the opposite side of the tip. The procedure is repeated
`between the open and closed positions. Requisites of ‘the
`on the opposite side of the tip where the thread enters
`material employed therefore are that it possess such
`I the fabric layers at point a’ is looped around through
`limited resiliency and is not susceptible to creep. For
`and into point b’, then passed through the loop formed
`instance, the stent may be molded from a polypropyl
`:as at c’ followed by drawing the suture together until
`en'e, ultra high density polyethylene, acetyl homo or
`the knots are tightly drawn against opposite sides of the
`copolymer materials. When laid out in a ?at pattern,
`tip with the threading c passing over the upper terminal
`depressed areas 20 are of generally elliptical con?gura
`edge of the tip.
`tion with opposite side edges of the posts diverging
`‘After a pair of lock knots k have been formed on
`away from tips 21 into the depressed areas. A plurality
`opposite sides of a tip, the remaining length of thread 0'
`of apertures or sewing holes 22 are formed at spaced
`is then passed through a succession of back stitches as
`intervals to serve as one means of anchoring the fabric
`designated at d, e, f and g, this procedure being repeated
`covering to the posts in a manner to be hereinafter
`throughout the length of the scalloped portion until the
`described. For the purpose of reference, the upstream
`next commissure post is reached. Again, at the next
`edge of the completed valve is located at the in?ow end
`commissure post, lock knots k are formed on opposite
`or base of the stent while the downstream or out?ow
`sides of the tip in the same manner as hereinbefore de
`end is along the posts 19; and in this relation the stent is
`scribed. After the stitching operation is completed
`arranged with the posts extending in the downstream
`,along the posts 19 and scalloped portions 20, the excess
`direction to support the natural tissue element 16 in
`‘ fabric along the scalloped portions and posts is trimmed
`outer surrounding relation to the posts, the valve ele
`as represented at h directly outside of the seam.
`ment 16 being pre-formed with three cusps 24 as shown
`
`a
`
`15
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`25
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`45
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`60 .
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`NORRED EXHIBIT 2102 - Page 5
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`

`

`15
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`25
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`35
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`5
`As a preliminary ‘to the next fabrication step, the
`basting B is removed so as to permit removal of the
`stent from the folded end of the tube and permit the
`folded end to be inverted, or turned inside out, so that
`the seam formed along the scalloped portion is hidden
`or directed inwardly between the folds of the fabric. As
`illustrated in FIG. 3, once inverted, the stent is rein
`serted into the inverted end with the shorter skirt por
`tion 32 again extending over the stent and the longer
`skirt portion extending within and beyond the stent
`notwithstanding that the folded end has been inverted.
`The stent is snugly inserted into the seamed or folded
`end of the fabric so as to be properly aligned with the
`lock knots snugly engaging opposite sides of each tip,
`following which the skirt portions are permanently
`stitched together along a circumferential base line 36
`directly beneath the lower edge of the stent. Anchor
`stitching as represented at 37 is performed by passing
`the thread through the fabric layers and sewing holes 22
`in each post, or in other words, passing the thread back
`and forth between the series of sewing holes so as to
`anchor opposite sides of the fabric covering securely to
`each post.
`In a second base stitching operation, as illustrated in
`FIG. 5, the skirt portions 32 and 33 are reversed or
`pulled over the first base stitching 36 and with the stent
`inverted as shown in FIG. 5 both will be directed down
`wardly over the exterior of the stent and the fabric
`covering. The skirt portions then are permanently fixed
`together and to the outer fabric covering on the stent
`along a second circumferential base line 38. In this
`stitching procedure, with a lock knot 1 and back stitch
`ing over one rib of the fabric followed by sliding under
`three ribs of the fabric, stitching is continued along the
`circumferential line until the ?rst post is reached, at
`which point a pocket 39 is form by leaving an area
`unstitched by a lock knot k, then sliding the needle for
`a limited distance to the opposite side of the post, form
`ing another lock knot k and proceeding until the entire
`base has been stitched along the second base line 38.
`FIGS. 6 and 7 illustrate the placement of the sewing
`ring 28 at the base of the stent. By reference to FIG. 7,
`it will be noted that the sewing ring 28' is of annular
`con?guration and in cross-section tapers from a ?at
`inner edge 40 outwardly to a somewhat pointed extrem
`ity 41. In addition, to encourage the ring to lay
`smoothly when the skirt portions are pulled over it in a
`manner to be described and so as to be angled somewhat
`upwardly toward the post end of the stent, a corner 42
`is trimmed off of the inner edge so as to form a beveled
`edge along the upper corner of the ?at surface portion
`40. The sewing ring is inserted between the skirt por
`tions 32 and 33 with the bottom corner of the ring rest
`ing against the second base stitch 38 and the trimmed or
`55
`upper corner 42 facing the posts 19 of the stent. The
`longer skirt portion 33 is of a length to be wrapped over
`the entire ring and with its terminal edge overlapping
`the shorter skirt portion 32 so that the skirt portions
`may be stitched together immediately above the second
`base line 38. As a preliminary to this stitching operation,
`and as best seen from FIG. 7, any excess fabric on the
`longer skirt 33 is trimmed to overlap the short skirt 32,
`and the skirt portions are closed together with a running
`stitch which connects the skirt 33 with the fabric cover
`ing over the stent except at the pocket areas 39, at
`which points the longer skirt portion is stitched to the
`shorter skirt 32.
`
`4,477,930
`6
`FIG. 10 illustrates the mounting and integration of
`the tissue valve element 16 into the stent and fabric
`cover. As a preliminary'to describing those steps, the
`preferred form of tissue valve element is a rectangular
`section of pericardium of uniform thickness which is cut
`from a partially ?xed pericardial sac. The partial ?xa
`tion is performed in a bath of tissue ?xative, such as, a
`glutaraldehyde solution. This is the only period before
`the ?nal ?xation during which the tissue will contact
`the ?xative. In accordance with conventional practice,
`the ?brous outer surface of the pericardium must be
`clear of fat and excess tissue. ‘The rectangular section of
`pericardium is attached to'the stent, as illustrated in
`FIG. 10, with the ?brous outer surface oriented to the
`in?ow aspect. The tissue is ?rst attached to the stent
`directly above the sewing ring 28 with the abutting
`edges of the tissue rectangle placed midway of one of
`‘the three commissure posts 19, the abutting edge por
`tion being designated at 48. In order to secure the tissue
`to the fabric covering over the stent above the‘ sewing
`ring 28, a continuous suture line is employed and which
`is tied off at each of the three commissure posts 19 with
`knots drawn into the pockets 39 left at the bases of the
`commissure posts 19 at the time of stent covering.
`As best seen from FIG. 10, attachment of the tissue at
`each commissure post 19 is accomplished with a contin
`uous criss-cross suture line 50.‘ All three commissures
`are attached in this manner with care being taken to
`insure equal amounts of tissue being left for the forma
`tion of each cusp 24. Most of the excess free margin
`tissue above the posts is trimmed prior to ?xation. FIG.
`9 illustrates a lea?et type form mandrel 54 which is
`inserted through the stent and tissue valve element 16
`with the hollowed-out portions 55 of the form mandrel
`aligned with the cusp portions 24 to be formed between
`the posts 19; i.e., along the scalloped portions 20. Fixa
`tion of the tissue is then carried out with the valve
`placed on the mandrel and immersed in a bath of tissue
`?xative, such as, a glutaraldehyde solution, for a period
`on the order of fourteen days. Application of mechani
`cal pressure to the valve is avoided in the ?xation of the
`valve so as to prevent distortion of the collagen bundles.
`Thus, it has been found that application of pressure to
`the tissue can be deleterious to the natural functioning
`of the collagen bundles so as to most closely simulate
`the human valve in operation. After ?xation, the valve
`is given a ?nal trim of excess tissue directly above the
`tips 21 of the posts so as to result in the completed valve
`as illustrated in FIG. 10.
`‘
`The preferred form of tissue valve as illustrated ?nds
`equal utility for placement either in the atrioventricular
`valves; i.e., as a mitral or tricuspid valve; or as the aortic
`or pulmonary valve. Conventional surgical procedures
`are followed in the implantation of the valve and specif
`ically by securing the outer sewing ring to the annulus
`or wall such that the cusps 24 on the valve are aligned
`in a downstream direction and will freely open to the
`maximum diameter of the stent under the opening pres
`sure of the blood. When the pressure is reversed, the
`cusps will automatically close to their original state so
`as to operate effectively as a check valve. From the
`foregoing, it will be evident that the procedure fol
`lowed in the fabrication and constructionof the valve
`achieves a number of important advantages in the art of
`tissue valves, most notable of which are the utilization
`of a single piece of fabric for covering the stent and
`sewing ring followed by the use of a single section of
`tissue which can be securely fastened and united with
`
`50
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`NORRED EXHIBIT 2102 - Page 6
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`

`

`4,477,930
`8
`7. In a prosthetic heart valve according to claim 6,
`the stent and fabric covering. In the resultant valve, no
`one of said skirt portions folded over said suture ring
`seams or knots are exposed’ so as. to minimize any ten
`and having a circumferential seam joining said one skirt
`dency to cause increased turbulence or interference in
`portion to said outer fold adjacent to said second base
`the blood?ow and to simulate as close as possible the
`working of a natural human valve for the heart.
`seam.
`8. In a prosthetic heart valve according to claim 1,
`Preferably, a tissue valve is bovine pericardium hav
`said suture ring inclining outwardly away from said
`ing a thickness related to the external diameter of the
`base in a direction toward said posts.
`stent and as indicated is selectedso as not to have any
`I
`9. A prosthetic heart valve comprising:
`blood vessels or excess'fat. The tissue is formed into a
`rectangular piece whichalong the section covering the
`an annular stent having a base at an upstream end and
`upright posts at spaced circumferential intervals
`base is of a‘ length corresponding to the outer circumfer
`along a downstream end of said stent;
`ence of the base of the covered stent so as to be able to
`be laid down, into the pocket between the sewing ring
`V a one-piece fabric cover in the form of a tube having
`inner and outer concentric folds between which
`28 and stent 12. Howeverrat the tip of the stent, the
`said stent is inserted such that said posts are dis
`tissue is of increased length so as to be somewhat
`posed at the juncture of said folds, a ?rst inverted
`crown-shaped or of frusto-conical con?guration toward
`seam in said fabric cover along said downstream
`the upper end or tips 21 of the stent. As described, the
`end of said stent, and a base seam joining said folds
`tissue is secured only to the external surfaces of the
`circumferentially along said upstream end;
`I
`commissure posts 19 so as to be free to open fully to a
`a suture ring anchored to said base; and
`diameter externally of the stent. Again, ?xation is not
`a tissue valve element of tubular con?guration dis
`performed until the tissue has been secured and
`posed in surrounding relation to said stent, said
`trimmed, then is permitted to be ?xed into the desired
`element having mating edges extending midway of
`vcon?guration without the application of pressure fol
`one of said posts and in a direction parallel to the
`lowed by sterilization and packaging in accordance
`direction of extension of said one-post, one end of
`with well-known practice.
`.
`said element being anchored to the base of said
`It is therefore to be understood that the foregoing
`stent in surrounding relation to said outer fold, and
`description of the construction of a natural tissue heart
`sutures extending in criss-cross relation through
`valve and method of making same is intended as a de
`said valve element to anchor said valve element to
`scription of a preferred embodiment only and that vari
`ous modi?cations, changes may=be made in the con
`each of said posts.
`I
`10. A prosthetic heart valve according to claim 9,
`struction and‘ method of fabrication with out departing
`said fabric cover de?ned by a bias cut fabric, and said
`from the. spirit and scope of the present invention as
`inverted seam having knots positioned in snug-?tting
`de?ned by the appended claims.
`engagement with opposite side'edges of each of said
`
`10
`
`20
`
`25
`
`30
`
`We claim:
`
`_
`
`I.
`
`.
`
`,
`
`,
`
`_
`
`.
`
`35
`
`posts.
`
`.
`
`.
`
`I
`
`1. In a prosthetic heart ‘valve wherein an annular stent
`having a base at an upstream end and upright posts at
`spaced circumferential intervals around the down
`stream end of saidstent, the improvement comprising:
`a one-piece fabric cover in the form of a tube having
`‘ inner and outer concentric folds with said stent
`inserted betweensaid folds such that said postsare
`disposed» at the juncture of said folds, a ?rst in
`verted seam inasaid‘ fabric cover along. said down—
`stream end of said stent, and a base seam joining
`said folds circumferentially along said upstream
`
`end; '
`
`'
`
`_
`
`.
`
`45
`
`11. A prosthetic heart valve according to claim 9,
`said inverted seam de?ned by a continuous length of
`thread looped upon itself to de?ne lock knots on oppo
`site side edges'of each post.
`12. A prosthetic heart valve according to claim 9,
`said fabric cover having inner and outer skirt portions
`extending from said base seam, said suture ring an
`choredbetween said inner and outer skirt portions, and
`said .skirt portions being folded over said outer fold
`along the base of said stent, and a second base seam
`joining said skirt portions to said outer fold in closely
`spaced relation to said base seam and at the inner edge
`of said suture ring.
`,
`13. A prosthetic heart valve according to claim 12,
`one of said skirt portions folded over said suture ring
`and having a circumferential seam joining said one skirt
`' portion to said outer fold adjacent to said second base
`seam.
`14. A prosthetic heart valve according to claim 12,
`said second base seam having pockets at spaced inter
`vals aligned with said posts for insertion of knots
`formed along the inner edge of said suture ring.
`15. The method of forming a prosthetic heart valve,
`comprising the steps of:
`'
`forming a tubular fabric cover;
`placing a stent having commissure posts over said
`tubular cover;
`reverse folding one end of said tubular cover over
`said stent whereby to de?ne inner and outer con
`centric folds along inner and outer surfaces of said
`stent;
`forming a seam between. said inner and outer folds
`along the downstream edge of said stent;
`
`a suture ring anchored to said base; and
`a tissue valve member circumscribing said stent and
`said outer fold.
`2. In a prosthetic heartvalve according to claim ‘1,
`said fabric cover de?ned by a bias cut fabric.
`3. In a prosthetic heart valve according to claim 1,
`said inverted, seam having knots positioned in snug-?t
`ting engagement with opposite side edges of each of
`55
`
`said posts.
`
`_
`
`..
`
`_
`
`-
`
`50
`
`4. In a prosthetic heart valve according to claim 1,
`said inverted seam de?ned by a continuous length of
`thread looped upon itself to de?ne lock knots on oppo
`site side edges of each post.
`'
`5. In a prostheticheart valve according to claim 1,
`said fabric cover having inner and outer skirt portions
`extending from said base seam, and said suture ring
`anchored betweensaid inner and outer skirt portions.
`6. In a prosthetic heart. valve according to claim 5,
`said skirt portions folded over said outer fold of fabric
`along the base of saidstent, and a second base seam
`joining said skirt portions to said outer fold in closely
`spaced relation to said base seam.
`
`60
`
`65
`
`NORRED EXHIBIT 2102 - Page 7
`
`

`

`4,477,930
`9
`10
`removing said stent from said tubular portion and
`centric folds along the inner and outer surfaces of
`inverting said tubular portion to place said seam
`said stent;
`forming a seam between said inner and outer folds
`inside of said inner and outer folds;
`along the downstream edge of said stent;
`reinserting said stent into position between said inner
`removing said stent from said tubular portion and
`and outer folds;
`inverting said tubular portion to place said seam
`stitching a base scam in a circumferential direction
`inside of said inner and outer folds;
`between said inner and outer folds and beneath the
`reinserting said stent into position between said inner
`upstream edge of said stent whereby to form inner
`and outer folds;
`and outer skirt portions in said fabric covering
`stitching a base seam in a circumferential direction
`which extend away from said stent and said base
`between said inner and outer folds and beneath the
`seam;
`upstream edge of said stent whereby to form inner
`reverse folding said inner and outer skirt portions
`and outer skirt portions in said fabric covering
`over said stent;
`which extend away from said stent and said base
`inserting a suture ring between said inner and outer
`seam;
`skirt portions; and
`reverse folding said inner and outer skirt portions
`folding one of said skirt portions over said suture ring
`over said stent;
`and said other skirt portion and stitching said one
`stitching a second base seam in a circumferential
`skirt portion in a circumferential direction whereby
`direction closely spaced to said first base seam
`to anchor said suture ring to said base.
`between said skirt portions and said outer fold
`16. The method according to claim 15, including the
`along the base of said stent;
`step of positioning a tissue valve element in surrounding
`inserting a suture ring between said inner and outer
`relation to said outer fold and said stent with one edge
`skirt portions into abutment with said second base
`of said valve element abutting said suture ring and the
`seam;
`opposite edge of said valve element extending beyond
`folding one of said skirt