Ulllted States Patent [19]
`Huynh et al.
`
`[54] TISSUE HEART VALVES
`
`[75] Inventors: Van Le Huynh, Tustin; Than Nguyen,
`Anaheim; Hung Ly Lam, Norco;
`Xiaoming G. Guo, Dove Canyon;
`Ra] h Kafes'ian New on Beach all
`P .
`J
`’
`p
`’
`of Cahf-
`
`_
`_
`[73] Ass1gnee: Baxter International Inc., Deer?eld,
`111-
`
`[21] Appl' No‘: 08/826 408
`’
`Mar‘ 27’ 1997
`
`Flled:
`
`[22]
`
`6
`[51] Int. Cl. ...................................................... .. A61F 2/24
`[52] US. Cl. ............................................... .. 623/2; 623/900
`[58] Field Of Search ........................................ .. 623/2, 900
`
`[56]
`
`References Cited
`
`U-S- PATENT DOCUMENTS
`4/1982 Hancock.
`Re. 30,912
`9/1973 Hancock.
`3,755,823
`3/1978 Civitello .
`4,078,468
`4/1978 Ionescu et al. .
`4,084,268
`8/1978 Carpentier et al. .
`4,106,129
`4,172,295 10/1979 Batten .
`4,218,782
`8/1980 Rygg .
`4,259,753
`4/1981 Liotta et al. .
`4,343,048
`8/1982 ROSS et a1~ -
`4,364,126 12/1982 Rosen et a1. .
`4,388,735
`6/1983 Ionescu et al. .
`4,441,216
`4/1984 Ionescu et al. .
`4,470,157
`9/1984 Love .
`4,501,030
`2/1985 Lane .
`4,506,394
`3/1985 Bedard .
`4,605,407
`8/1986 Black et a1. .............................. .. 623/2
`4,626,255 12/1986 Reichart et al. .
`4,629,459 12/1986 Ionescu et al. .
`4,731,074
`3/1988 Rousseau et al. .
`4,778,461 10/1988 Pietsch et al. .
`4,851,000
`7/1989 Gupta .
`4,888,009 12/1989 Lederman et al. .
`5,037,434
`8/1991 Lane .
`5,147,391
`9/1992 Lane .
`5,163,955 11/1992 Love et al. .
`5,258,023 11/1993 Reger .
`
`US005928281A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,928,281
`Jul. 27, 1999
`
`7/1994 Love et a1. .
`5,326,370
`7/1994 Love et al. .
`5,326,371
`5,376,112 12/1994 Duran -
`5,423,887
`6/1995 Love et al. .
`5’425’741
`6/1995 Lemp et a1‘ '
`5,449,384
`9/1995 J°h“S°“'
`5,449,385
`9/1995 Religa et al. .
`5,469,868 11/1995 Reger.
`5,488,789
`2/1996 Religa et al. .
`574897297
`2/1996 Duran _
`5,489,298
`2/1996 Love et al. .
`5,500,016
`3/1996 Fisher.
`5,562,729 10/1996 Purdy et a1. .............................. .. 623/2
`5,800,527
`9/1998 Jansen et al. ............................. .. 623/2
`FOREIGN PATENT DOCUMENTS
`
`0 071 610 B1 9/1982 European Pat‘ Off‘ '
`0 084 395 B1 8/1986 European Pat Om _
`0 096 721 B1 12/1987 European Pat. Off. .
`0 125 393 B1 12/1987 European Pat. Off. .
`0 179 562 B1 7/1989 European Pat. Off. .
`2 056 023 3/1981 United Kingdom .
`2 069 843 9/1981 United Kingdom ..................... .. 623/2
`28573021333 15%;; $11551 Kingdom '
`91/15167 “V1991 WIPO'
`92
`'
`/12690 8/1992 WIPO .
`92/19184 11/1992 WIPO
`92/19185 11/1992 WIPO '
`9508899 11/1995 WIPO '
`'
`Primary Examiner—David H. Willse
`Attorney, Agent, or Firm—Kurt M. Maclean; Guy L.
`Cumberbatch
`[57]
`
`ABSTRACT
`
`Improved, adaptable tissue-type heart valves and methods
`for their manufacture are disclosed Wherein a dimensionally
`stable, pre-aligned tissue lea?et subassembly is formed and
`its peripheral edge clamped betWeen and attached to an
`upper shaped Wireform and a loWer support stent. Avariety
`of adaptable structural interfaces including suture rings,
`?anges, and conduits may be attached to the support stent
`With or Without an outlet conduit disposed about the Wire
`form to provide a tissue-type heart valve adaptable for use
`in either a natural heart or in mechanical pumping devices.
`
`47 Claims, 16 Drawing Sheets
`
`NORRED EXHIBIT 2207 - Page 1
`Medtronic, Inc., Medtronic Vascular, Inc.,
`& Medtronic Corevalve, LLC
`v. Troy R. Norred, M.D.
`Case IPR2014-00111
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 1 0f 16
`
`5,928,281
`
`NORRED EXHIBIT 2207 - Page 2
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 2 0f 16
`
`5,928,281
`
`NORRED EXHIBIT 2207 - Page 3
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 3 0f 16
`
`5,928,281
`
`59
`
`90
`
`5?
`
`68
`
`54/
`
`NORRED EXHIBIT 2207 - Page 4
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 4 0f 16
`
`5,928,281
`
`NORRED EXHIBIT 2207 - Page 5
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 5 0f 16
`
`5,928,281
`
`jar. f0.
`
`NORRED EXHIBIT 2207 - Page 6
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 6 0f 16
`
`5,928,281
`
`f0! »
`
`1:‘:
`
`-
`
`fdé
`
`NORRED EXHIBIT 2207 - Page 7
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 7 0f 16
`
`5,928,281
`
`--/00
`
`NORRED EXHIBIT 2207 - Page 8
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 8 0f 16
`
`5,928,281
`
`NORRED EXHIBIT 2207 - Page 9
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 9 0f 16
`
`5,928,281
`
`Jim: 17
`
`NORRED EXHIBIT 2207 - Page 10
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 10 0f 16
`
`5,928,281
`
`1a Z].
`
`NORRED EXHIBIT 2207 - Page 11
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 11 0f 16
`
`5,928,281
`
`NORRED EXHIBIT 2207 - Page 12
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 12 0f 16
`
`5,928,281
`
`I6: 27.
`
`fJO
`
`J61 30.
`
`I6: 31
`
`NORRED EXHIBIT 2207 - Page 13
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 13 0f 16
`
`5,928,281
`
`m5
`
`f5!
`
`150
`1/94
`
`M9
`
`190
`
`£6, 25:
`
`NORRED EXHIBIT 2207 - Page 14
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 14 0f 16
`
`5,928,281
`
`NORRED EXHIBIT 2207 - Page 15
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 15 0f 16
`
`5,928,281
`
`?e 3'5.
`
`is: 37
`
`J6: Jé.
`
`NORRED EXHIBIT 2207 - Page 16
`
`

`
`U.S. Patent
`
`Jul. 27, 1999
`
`Sheet 16 0f 16
`
`5,928,281
`
`NORRED EXHIBIT 2207 - Page 17
`
`

`
`5,928,281
`
`1
`TISSUE HEART VALVES
`
`FIELD OF THE INVENTION
`
`The present invention is directed to tissue-type prosthetic
`heart valves and to improved methods of making such
`valves.
`
`BACKGROUND OF THE INVENTION
`
`Prosthetic heart valves are used to replace damaged or
`diseased heart valves. In vertebrate animals, the heart is a
`holloW muscular organ having four pumping chambers: the
`left and right atria and the left and right ventricles, each
`provided With its oWn one-Way valve. The natural heart
`valves are identi?ed as the aortic, mitral (or bicuspid),
`tricuspid and pulmonary valves. Prosthetic heart valves can
`be used to replace any of these naturally occurring valves.
`TWo primary types of heart valve replacements or prostheses
`are knoWn. One is a mechanical-type heart valve Which uses
`a pivoting mechanical closure to provide unidirectional
`blood ?oW. The other is a tissue-type or “bioprosthetic”
`valve Which is constructed With natural-tissue valve lea?ets
`Which function much like a natural human heart valve,
`imitating the natural action of the ?exible heart valve lea?ets
`Which seal against each other or coapt betWeen adjacent
`tissue junctions knoWn as commissures. Each type of pros
`thetic valve has its oWn attendant advantages and draW
`backs.
`Operating much like a rigid mechanical check valve,
`mechanical heart valves are robust and long lived but require
`that valve implant patients utiliZe blood thinners for the rest
`of their lives to prevent clotting. They also generate a
`clicking noise When the mechanical closure seats against the
`associated valve structure at each beat of the heart. In
`contrast, tissue-type valve lea?ets are ?exible, silent, and do
`not require the use of blood thinners. HoWever, naturally
`occurring processes Within the human body may attack and
`stiffen or “calcify” the tissue lea?ets of the valve over time,
`particularly at high-stress areas of the valve such as at the
`commissure junctions betWeen the valve lea?ets and at the
`peripheral lea?et attachment points or “cusps” at the outer
`edge of each lea?et. Further, the valves are subject to
`stresses from constant mechanical operation Within the
`body. Accordingly, the valves Wear out over time and need
`to be replaced. Tissue-type heart valves are also consider
`ably more difficult and time consuming to manufacture.
`Though both mechanical-type and tissue-type heart
`valves must be manufactured to exacting standards and
`tolerances in order to function for years Within the dynamic
`environment of a living patient’s heart, mechanical-type
`replacement valves can be mass produced by utiliZing
`mechaniZed processes and standardiZed parts. In contrast,
`tissue-type prosthetic valves are made by hand by highly
`trained and skilled assembly Workers. Typically, tissue-type
`prosthetic valves are constructed by seWing tWo or three
`?exible natural tissue lea?ets to a generally circular sup
`porting Wire frame or stent. The Wire frame or stent is
`constructed to provide a dimensionally stable support struc
`ture for the valve lea?ets Which imparts a certain degree of
`controlled ?exibility to reduce stress on the lea?et tissue
`during valve closure. Abiocompatible cloth covering on the
`Wire frame or stent provides seWing attachment points for
`the lea?et commissures and cusps. Similarly, a cloth covered
`suture ring can be attached to the Wire frame or stent to
`provide an attachment site for seWing the valve structure in
`position Within the patient’s heart during a surgical valve
`replacement procedure.
`
`10
`
`15
`
`25
`
`35
`
`45
`
`55
`
`65
`
`2
`With over ?fteen years of clinical experience supporting
`their utiliZation, tissue-type prosthetic heart valves have
`proven to be an unquali?ed success. Recently their use has
`been proposed in conjunction With mechanical arti?cial
`hearts and mechanical left ventricular assist devices
`(LVADs) in order to reduce damage to blood cells and the
`associated risk of clotting Without using blood thinners.
`Accordingly, a need is developing for a tissue-type pros
`thetic heart valve that can be adapted for use in conjunction
`With such mechanical pumping systems. This developing
`need for adaptability has highlighted one of the draWbacks
`associated With tissue-type valves—namely, the time con
`suming and laborious hand-made assembly process. In order
`to provide consistent, high-quality tissue-type heart valves
`having stable, functional valve lea?ets, highly skilled and
`highly experienced assembly personnel must meticulously
`Wrap and seW each lea?et and valve component into an
`approved, dimensionally appropriate valve assembly.
`Because of variations in tissue thickness, compliance and
`stitching, each completed valve assembly must be ?ne tuned
`using additional hand-crafted techniques to ensure proper
`coaptation and functional longevity of the valve lea?ets. As
`a result, neW challenges are being placed upon the manu
`facturers of tissue-type prosthetic valves in order to meet the
`increasing demand and the increasing range of uses for these
`invaluable devices.
`Accordingly, consistent With the developing practice of
`the medical profession, there is a continuing need for
`improved tissue-type prosthetic heart valves Which incorpo
`rate the lessons learned in clinical experience, particularly
`the reduction of stress on the valve lea?ets While maintain
`ing desirable structural and functional features. Additionally,
`there is a growing need for improved tissue-type prosthetic
`heart valves Which can be adapted for use in a variety of
`positions Within the natural heart or in mechanical pumps,
`such as arti?cial hearts or ventricular assist devices, as Well
`as alternative locations in the circulatory system. Further, in
`order to address groWing demand for these devices, there is
`a need for tissue-type heart valves that are simpler and easier
`to manufacture in a more consistent manner than are existing
`valves.
`
`SUMMARY OF THE INVENTION
`Directed to achieving the foregoing objective and to
`remedying the problems in the prior art, disclosed herein are
`novel tissue heart valve constructions and components
`thereof, and simpli?ed methods of fabricating the same. The
`improved tissue heart valves of the present invention are
`fabricated to include standardiZed lea?et structure subas
`semblies that can be modi?ed readily to adapt to different
`intended applications. Of equal importance, the lea?et struc
`ture subassemblies uniformly distribute tensile loads along
`the entire peripheral lea?et cusp, reducing stress points and
`signi?cantly improving the long-term functionality of the
`valve assembly. As an added bene?t of the present invention,
`the stability and adaptability of the tissue valve subassembly
`is achieved through simpli?ed manufacturing processes uti
`liZing feWer steps and subassemblies. This manufacturing
`protocol can be incorporated into branched, adaptable manu
`facturing techniques for the production of tissue heart valves
`having a variety of end uses. Further, these improved
`construction techniques expedite the overall manufacturing
`process and improve the consistency of the tissue valves so
`produced While simultaneously reducing the need for post
`assembly ?ne tuning and quality-control procedures.
`According to one aspect of the present invention, a
`tissue-type heart valve includes a dimensionally stable,
`
`NORRED EXHIBIT 2207 - Page 18
`
`

`
`5,928,281
`
`3
`pre-aligned tissue lea?et subassembly, a generally circular
`Wireform, and a generally circular support stent. The Wire
`form has a bottom surface dimensioned to receive the
`pre-aligned tissue lea?et subassembly in ?xed, mating
`engagement. The support stent has an upper surface dimen
`sioned to seat and ?x in meeting engagement With the
`pre-aligned tissue lea?et subassembly Which is ?xedly dis
`posed in mating engagement With the bottom surface of the
`Wireform.
`Pursuant to this construction, an exemplary tissue valve
`includes a plurality of tissue lea?ets Which are templated and
`attached together at their tips to form a dimensionally stable
`and dimensionally consistent coapting lea?et subassembly.
`Then, in What is essentially a single process, each of the
`lea?ets of the subassembly is aligned With and individually
`seWn to a cloth-covered Wireform, from the tip of one
`Wireform commissure uniformly, around the lea?et cusp
`perimeter, to the tip of an adjacent Wireform commissure. As
`a result, the seWed sutures act like similarly aligned staples,
`all of Which equally take the loading force acting along the
`entire cusp of each of the pre-aligned, coapting lea?ets. The
`resulting tissue-Wireform structural assembly thereby
`formed reduces stress and potential fatigue at the lea?et
`suture interface by distributing stress evenly over the entire
`lea?et cusp from commissure to commissure. This
`improved, dimensionally stable, reduced-stress assembly is
`operatively attached to the top of a previously prepared
`cloth-covered stent to clamp the tissue lea?et cusps on a
`load-distributing cloth seat formed by the top of the cloth
`covered stent Without distorting the lea?ets or disturbing
`their relative alignment and the resultant coaptation of their
`mating edges.
`The stent is secured to the assembly With the commissures
`of the stent extending up into the corresponding commis
`sures of the lea?et, Wireform assembly. The stent itself can
`be formed of an inner polyester ?lm support secured to a
`surgically acceptable metal ring such as an ElgiloyTM metal
`stiffener having a cloth cover cut, folded and seWn around
`the support and stiffener combination. Alternatively, instead
`of having an Elgiloy outer band and a laminated polyester
`?lm support, the tWo stent layers can both be polyester
`layers or a single piece stent having appropriately ?exible
`commissure posts. Either stent construction provides sup
`port and dimensional stability for the valve structure extend
`ing from commissure to commissure and being evenly
`distributed around each lea?et. This assembly methodology
`alloWs the evenly sutured tissue of the lea?et cusps to be
`sandWiched betWeen the Wireform and the stent and to
`thereby further distribute the loading forces more evenly
`around the attachment site. Because the tissue lea?ets expe
`rience loWer, more evenly distributed stresses during
`operation, they are less likely to experience distortion in use.
`Thus, a more stable, long lived, functional closure or coap
`tation of the lea?ets is provided by this even distribution of
`attachment forces.
`Anumber of additional advantages result from the present
`invention and the stent construction utiliZed therein. For
`example, for each key area of the stent, the ?exibility can be
`optimiZed or customiZed. If desired, the coapting tissue
`lea?et commissures can be made more or less ?exible to
`alloW for more or less de?ection to relieve stresses on the
`tissue at closing or to ?ne tune the operation of the valve.
`Similarly, the base radial stiffness of the overall valve
`structure can be increased or decreased to preserve the
`roundness and shape of the valve.
`Unlike a rigid mechanical valve, the stent does not act as
`a rigid heart valve structure but as a radially stable, yet
`
`10
`
`15
`
`25
`
`35
`
`45
`
`55
`
`65
`
`4
`axially ?exible support. A rigid structure is unnecessary by
`utiliZing the teachings of the present invention because the
`valve lea?ets are dimensionally pre-aligned along their
`mutually coapting mating or sealing edges prior to being
`directly attached to the base of the cloth-covered Wireform.
`As a result, the entire sealing aspect of the valve can be
`aligned in three dimensions at once Without the variability
`previously experienced in the construction of prior art
`tissue-type valves. In addition to eliminating the need for
`post-assembly adjustment, this pre-alignment provides for
`consistency and simplicity in the manufacture of the valve
`structure. Further, the Wireform functions as a template for
`suturing the lea?et cusps to the valve subassembly With
`uniform stitching from commissure tip to commissure tip.
`This produces a dimensionally consistent structure Which
`can interface With the stent in a previously unobtainable
`uniform manner. The consistent dimensional integrity of the
`lea?et Wireform subassembly enables the stent to function as
`a stress relieving support clamp Which further secures the
`lea?et cusps in the valve structure to provide an added
`degree of stability and stress distribution. If desired, pro
`viding the top of the stent With a single or double fold of
`covering cloth provides the stent lip With a deformable cloth
`seat that assists in the distribution of load around the lea?et
`cusps and simpli?es seWing the stent to the tissue lea?et
`Wireform subassembly. Those skilled in the art Will appre
`ciate that attaching the stent to the tissue lea?et Wireform
`functions to stabiliZe the projecting commissure posts of the
`valve subassembly Without stiffening their desirable axial
`?exibility. This novel construction technique eliminates the
`need for separate commissure posts at the tissue lea?et
`commissures and also eliminates multiple tissue and cloth
`layers at the Wireform commissure posts Which adds to
`uniformity and consistency in valve production and elimi
`nates assembly steps. As a result, valve manufacture is not
`only improved, but simpli?ed and expedited as Well.
`The stent also functions as an adaptable structural
`interface, alloWing the tissue-Wireform-stent structural sub
`assembly to be attached to a variety of additional structures
`dependent upon intended valve placement and operating
`environments. For example, With the supporting stent
`secured to the tissue-Wireform structural assembly, the
`resulting valve assembly can be attached to, for example, a
`suture ring, a ?ange or a conduit depending on the desired
`valve application. To form a conduit valve, the suture ring
`can be attached directly to the in?oW or base of the stent to
`enable the implanting surgeon to seW the valve in place
`Within the heart. Alternatively, When the valve is to be used
`for arti?cial hearts or for left ventricular assist devices
`(LVADs), a more rigid ?ange can be attached to the stent
`in?oW to function as a mechanical mount. In some circum
`stances it may be desirable to form a conduit valve Wherein
`?exible or rigid conduits are required to replace a missing
`portion of a patient’s aorta or to interface With an arti?cial
`blood pumping device. In such circumstances, an inlet
`conduit may be attached to the stent in?oW and, if desired,
`a corresponding out?oW conduit can be attached inside or
`outside of the valve Wireform. Unlike prior art tissue heart
`valves, the present invention provides this ?exibility and
`adaptability of use because key valve components can be
`standardiZed for different types of valves or valve applica
`tions. This manufacturing and structural consistency also
`improves quality control and provides repeatability and
`consistency in the formation of the valves. It also simpli?es
`?nal assembly Which in turn provides for increased produc
`tion rates Without sacri?cing consistent product quality.
`More speci?cally, as part of the ?exibility of the present
`invention, the stent is designed to be adaptable so that
`
`NORRED EXHIBIT 2207 - Page 19
`
`

`
`5,928,281
`
`5
`different Ways of attaching the valve to its various intended
`applications can be accommodated. The novel construction
`Which allows for this universal application results from the
`stent providing a complete uniform support to the dimen
`sionally stable, pre-aligned Wireform/lea?et subassembly.
`Because of this adaptability, the valve of the present inven
`tion can function in a variety of applications, including that
`of a temporary heart valve prosthesis Within a circulatory
`support system using a relatively rigid ?ange or a conduit
`assembly rather than a standard soft seWing ring.
`Alternatively, the present invention can function as a pros
`thetic valve having a soft, scallop-shaped seWing ring for
`aortic positioning or a soft ?at seWing ring for mitral
`positioning, or as a conduit valve by incorporating proximal
`and distal conduits attached on both the in?oW and out?oW
`valve ends. The out?oW conduit can have a sinus shape to
`improve blood ?oW if desired. Within an arti?cial heart
`system, the valve of the present invention mimics the
`hemodynamic pumping action of the heart While sustaining
`the patient until a donor heart is located and successfully
`transplanted. In this application, both blood in?oW and
`out?oW functions can be accommodated by the present
`invention.
`Other objects and advantages of the present invention Will
`become more apparent to those persons having ordinary skill
`in the art to Which the present invention pertains from the
`folloWing description taken in conjunction With the accom
`panying draWings.
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is an exploded perspective vieW of an exemplary
`heart valve of the present invention illustrating the assembly
`relationship of the standardiZed components and alternative
`valve attachment application structures;
`FIG. 2 is a perspective vieW illustrating the step of
`templating and trimming exemplary lea?ets used in making
`a tissue heart valve of the present invention;
`FIG. 3 illustrates the initial steps of templating and
`pre-aligning the lea?ets of the valve subassembly;
`FIG. 4 shoWs additional steps in the pre-alignment of the
`valve lea?et subassembly;
`FIG. 5 is an enlarged vieW illustrating an exemplary
`attachment step of the pre-aligned lea?ets to a Wireform
`commissure tip;
`FIG. 6 is a perspective vieW illustrating the subsequent
`preliminary attachment of the exemplary lea?et cusps to the
`Wireform of FIG. 5;
`FIG. 7 is a perspective vieW illustrating the uniform
`attachment of the perimeter cusps of lea?ets to the cloth
`covered Wireform;
`FIG. 8 is an enlarged vieW of one of the pairs of attached
`lea?et tabs of FIG. 7 illustrating the uniform attachment of
`the cusps to the Wireform commissure tip;
`FIG. 9 is a perspective vieW illustrating the attachment of
`the exemplary tissue lea?et-Wireform structural subassem
`bly to an exemplary stent of the present invention;
`FIG. 10 is an enlarged vieW of one of the pairs of lea?et
`tabs of FIG. 9 illustrating a further attachment step of the
`stent to the Wireform at the commissure tip, clamping the
`lea?et cusps therebetWeen;
`FIG. 11 is an enlarged vieW of one of the commissure tips
`of the tissue-Wireform structural assembly of FIG. 10 illus
`trating the clamping of the lea?ets by the stent;
`FIG. 12 is a perspective vieW illustrating a ?nal attach
`ment step of the exemplary tissue-Wireform structural
`assembly to the stent;
`
`1O
`
`15
`
`25
`
`35
`
`45
`
`55
`
`6
`FIG. 13 is an enlarged vieW taken on circle 13 of FIG. 12
`illustrating additional exemplary attachment techniques;
`FIG. 14 is an enlarged vieW taken on circle 14 of FIG. 12
`illustrating additional exemplary attachment techniques;
`FIG. 15 is a perspective vieW illustrating an exemplary
`attachment step of the tissue lea?et tabs at the commissure
`t1P;
`FIG. 16 is a vieW similar to FIG. 15 illustrating an
`alternative attachment step;
`FIG. 17 is an exploded perspective vieW illustrating an
`exemplary multi-piece stent formed of a ?exible support and
`an associated stiffener of the present invention;
`FIG. 18 is a perspective vieW illustrating the attachment
`of the support to the stiffener of FIG. 17;
`FIG. 19 is a perspective vieW illustrating an initial step in
`the covering of the stent components of FIG. 18 With cloth;
`FIG. 20 is an enlarged vieW of the top of FIG. 19
`illustrating additional steps in the attachment of the cloth to
`the stent components;
`FIG. 21 is a perspective vieW illustrating additional steps
`of fabricating seWing tabs for attaching the cloth to the stent
`components;
`FIG. 22 is an enlarged vieW of a portion of FIG. 20
`illustrating subsequent fabrication steps;
`FIG. 23 is an enlarged cross-sectional vieW taken on line
`23—23 of FIG. 22;
`FIG. 24 is a vieW similar to FIG. 22 illustrating additional
`fabrication steps;
`FIG. 25 is a perspective vieW of the cloth-covered stent of
`FIG. 18 illustrating the cloth seating lip;
`FIG. 26 is an enlarged cross-sectional vieW on line
`26—26 of FIG. 25 illustrating additional aspects of the
`fabrication of the exemplary stent assembly;
`FIG. 27 is a perspective vieW illustrating initial compo
`nents of an exemplary suture ring of the present invention;
`FIG. 28 is an enlarged cross-sectional vieW illustrating
`aspects of the fabrication of the exemplary suture ring; FIG.
`29 is a perspective vieW illustrating additional features of the
`exemplary suture ring assembly;
`FIG. 30 is an enlarged sectional vieW of a portion of FIG.
`29 illustrating additional aspects of the fabrication of the
`suture ring assembly;
`FIG. 31 is an enlarged sectional vieW illustrating addi
`tional aspects of the ?nished exemplary suture ring assem
`bly;
`FIG. 32 is an exploded perspective vieW illustrating
`positioning and assembly of a suture ring and lea?et sub
`assembly con?guration;
`FIG. 33 is a top perspective vieW illustrating additional
`suture ring lea?et subassembly attachment steps;
`FIG. 34 is a bottom perspective vieW illustrating further
`exemplary suture ring attachment steps;
`FIG. 35 is a cutaWay perspective vieW illustrating an
`exemplary attachment of an out?oW conduit to an exemplary
`valve of the present invention;
`FIG. 36 is an enlarged cross-sectional vieW illustrating
`additional aspects of the conduit attachment;
`FIG. 37 is a cross sectional vieW similar to FIG. 36
`illustrating alternative conduit attachment features; and
`FIG. 38 is an exploded perspective vieW illustrating
`additional valve attachment alternatives of the present
`invention.
`
`65
`
`DETAILED DESCRIPTION OF EXEMPLARY
`EMBODIMENTS
`Referring more particularly to the draWings, FIG. 1 is an
`exploded assembly vieW, illustrating exemplary alternative
`
`NORRED EXHIBIT 2207 - Page 20
`
`

`
`5,928,281
`
`7
`embodiments of an improved, adaptable tissue valve 50, its
`individual components, and its alternative configurations
`produced in accordance with the teachings of the present
`invention. Valve 50 includes a pre-aligned, standardized
`leaflet subassembly 52, a cloth-covered wireform 54 and a
`support stent 56. As will be discussed in detail below, during
`assembly of valve 50, the pre-aligned leaflet subassembly 52
`and the cloth-covered wireform 54 are first assembled in
`
`invention to form a tissue-
`accordance with the present
`wireform structural assembly 58 (see FIGS. 2 to 9). Then,
`the structural assembly 58 is secured to stent 56 to form the
`assembled valve 50.
`
`As illustrated FIG. 1, valve 50 is uniquely configured to
`enable production of several useful alternative valves for a
`variety of end-use applications. For example, if the desired
`application is the replacement of a native heart valve, valve
`50 can be attached to a relatively soft suture ring 60 for
`subsequent sewing into place within a heart (not shown).
`Alternatively,
`if it
`is desired to use valve 50 in a left
`ventricular assist device (LVAD) or in a mechanical heart
`pump, valve 50 can be mounted to an appropriately rigid
`mechanical flange 62. Further, in both natural and mechani-
`cal applications where it
`is desirable to incorporate a
`conduit, valve 50 may be attached to either an inflow conduit
`64 and/or an outflow conduit 66.
`
`Production of the Tissue-Wireform Structural Assembly
`In the present disclosure, exemplary valve 50 is illustrated
`as a three-leaflet or tricuspid valve. However, it will be
`appreciated by those skilled in the art that valve 50 may be
`configured to have two leaflets or any other desired leaflet
`configuration depending on the intended application.
`A first step in the assembly of tissue valve 50 is the
`attachment of tissue leaflets 68 to one another to form a
`
`consistently dimensioned, standardized leaflet subassembly.
`Tissue leaflets are typically formed from pericardial, porcine
`or similar tissue obtained from donor organs, which tissue is
`preserved or “fixed” prior to use in assembling a valve.
`Those skilled in the art will appreciate that the dimensions
`of leaflet subassembly 52 will vary depending upon the
`intended end use and associated positioning and dimensional
`requirements of the finished valve. However, pre-alignment
`and stitching in accordance with the teachings of the present
`invention not only simplifies the manufacture of valve 50
`but also functions to align the entire valve mating or seating
`surfaces at once. This eliminates variations in leaflet align-
`ment and dimensional relationships and significantly mini-
`mizes the need to adjust the tissue leaflets after final assem-
`bly of the valve in order to ensure proper coaptation at the
`mating edges of the leaflets.
`Referring now to FIG. 2, the desired number of tissue
`leaflets 68 (in this example, three leaflets) are obtained from
`natural tissue as known in the art, and each leaflet 68 is
`trimmed to the appropriate desired shape and size for the
`intended valve use using template 69, defining a generally
`straight or linear coapting mating edge 70 having opposing
`ends 71, 72 and a generally arcuate peripheral cusp 73
`extending therebetween. More particularly, each leaflet 68 is
`placed on a cutting board 74 and the selected template 69 is
`then placed over the leaflet 68. Tissue 75 extending beyond
`the boundaries of template 69 is then cut away using a sharp
`razor blade 76 or similar cutting tool.
`A characteristic of pericardial tissue is that one surface is
`smoother than the opposite surface. Accordingly, it is desir-
`able that the less smooth surface be identified to serve as the
`
`mating surface at edge 70 with an adjacent leaflet edge 70.
`After the leaflets 68 are trimmed and the mating surfaces
`
`8
`identified, two of the leaflets 68a, 68b are pre-aligned or
`mated together along with template 69 as shown in FIG. 3.
`The two leaflets 68a, 68b are then attached or stitched
`together at one end 71 to define the first in a plurality of pairs
`of aligned, mating leaflet ends. For example, a needle that
`has been “double-threaded,” that is, needle 78 that has been
`threaded with a looped (or “folded”) segment of thread 80 is
`inserted and pushed through the leaflets 68a, 68b at the
`location dictated by guide slot 82 at one end of template 69.
`Template 69 may then be removed, with needle 78 being
`brought over the top of leaflets 68a, 68b and passed back
`through the loop and pulled tightly. Naturally, alternative
`attachment methods or stitches may be utilized within the
`scope and teaching of the present invention. The opposite
`ends 72 of the first two leaflets 68a, 68b of the exemplary
`three leaflet valve are not sewn together at this time.
`Referring now to FIG. 4, a third leaflet 68c is pre-aligned
`and attached to the other two leaflets 68a, 68b in a tricuspid
`format, again using template 69. In particular, third leaflet
`68c is mated with template 69, and the respective unsewn
`ends 72 of the first two leaflets 68a, 68b are spread out and
`then aligned with the respective opposite ends 71, 72 of
`templated third leaflet 68c. Again using guide slot 82 of the
`template 69 as a guide, a double-threaded needle with thread
`80 is inserted through each of the unsewn pairs of the three
`leaflets 68a, 68b, 68c to secure the leaflet ends together in
`pairs as shown. The tem