PCT
`WORLD INTELLECTUAL PROPERTY ORGANIZATION
`International Bureau
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`(51) International Patent Classification 6 :
`WO 98/29057
`(11) International Publication Number:
`A61F 2/24
`
`Al
`
`(43) International Publication Date:
`
`9 July 1998 (09.07.98)
`
`(21) International Application Number:
`
`PCT/EP97/07337
`
`(22) International Filing Date:
`
`31 December 1997 (31.12.97)
`
`(30) Priority Data:
`96402929.2
`31 December 1996 (31.12.96)
`(34) Countries for which the regional or
`international application was filed:
`
`EP
`
`GB et al.
`
`(71) Applicant (for all designated States except US): CORDIS
`CORPORATION [US/US]; 40 Technology Drive, Warren,
`NJ 07059 (US).
`
`(72) Inventors; and
`(75) Inventors/Applicants (for US only): LETAC, Brice [FR/FR];
`15, allee de la Cedraie, F-76130 Mont-Saint-Aignan (FR).
`CRIBIER, Alain [FR/FR]; 2, rue Alain, F-76150 Maromme
`(FR).
`
`(74) Agents: GUTMAN, Ernest et al.; Ernest Gutman - Yves
`Plasseraud S.A., 3, rue Chauveau-Lagarde, F-75008 Paris
`(FR).
`
`(81) Designated States: AL, AM, AT, AU, AZ, BA, BB, BG, BR,
`BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE,
`GH, GM, OW, HU, IL, IS, JP, KE, KG, KP, KR, KZ, LC,
`LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX,
`NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM,
`TR, TT, UA, UG, US, UZ, VN, YU, ZW, ARIPO patent
`(OH, GM, KE, LS, MW, SD, SZ, UG, ZW), Eurasian patent
`(AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), European patent
`(AT, BE, CH, DE, DK, ES, FI, FR, GB , GR, IE, IT, LU,
`MC, NL, PT, SE), OAPI patent (BF, BJ, CF, CG, CI, CM,
`GA, GN, ML, MR, NE, SN, TD, TG).
`
`Published
`With international search report.
`Before the expiration of the time limit for amending the
`claims and to be republished in the event of the receipt of
`amendments.
`
`(54) Title: VALVE PROSTHESIS FOR IMPLANTATION IN BODY CHANNELS
`
`(57) Abstract
`
`The present
`invention
`is
`aimed to provide a valve prothesis
`(IV) especially used in case of
`aortic stenosis, which structure is
`capable of resisting the powerful
`recoil
`force and
`to stand
`the
`forceful balloon inflation performed
`to deploy the valve and to embed
`it in the ao1tic annulus. A valve
`prothesis (13) for implantation in
`a body channel according to the
`invention comprises a collapsible
`valvular structure
`(14) and an
`expandable frame (10, 10') on
`which said valvular structure (14)
`is mounted. The valvular structure
`(14) is composed of a valvular
`tissue compatible with the human
`body and blood, the valvular tissue being sufficiently supple and resistant to allow said valvular structure (14) to be defo1med from a
`closed state to an opened state. Said valvular tissue forms a continuous surface and is provided with guiding means (17) formed or
`incorporated within, said guiding means creating stiffened zones which induce said valvular structure (14) to follow a patterned movement
`in its expansion to its opened state and in its turning back to its closed state. The valvular structure can be extended to an internal cover
`(19) which is fastened to the lower end (15) of the valvular structure to prevent from regurgitation.
`
`19
`
`Medtronic Exhibit 1012
`Medtronic Corevalve v. Colibri Heart Valve
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`FOR THE PURPOSES OF INFORMATION ONLY
`
`Codes used to identify States party to the PCT on the front pages of pamphlets publishing international applications under the PCT.
`
`AL
`AM
`AT
`AU
`AZ
`BA
`BB
`BE
`BF
`BG
`BJ
`BR
`BY
`CA
`CF
`CG
`CH
`CI
`CM
`CN
`cu
`CZ
`DE
`DK
`EE
`
`Albania
`Annenia
`Austria
`Australia
`Azerbaijan
`Bosnia and Herzegovina
`Barbados
`Belgium
`Burkina Faso
`Bulgaria
`Benin
`Brazil
`Belarus
`Canada
`Central African Republic
`Congo
`Switzerland
`Cote d'Ivoire
`Cameroon
`China
`Cuba
`Czech Republic
`Germany
`Denmark
`Estoni a
`
`ES
`FI
`FR
`GA
`GB
`GE
`GH
`GN
`GR
`HU
`IE
`IL
`IS
`IT
`JP
`KE
`KG
`KP
`
`KR
`KZ
`LC
`LI
`LK
`LR
`
`Spain
`Finland
`France
`Gabon
`United Kingdom
`Georgia
`Ghana
`Guinea
`Greece
`Hungary
`Ireland
`Israel
`Iceland
`Italy
`Japan
`Kenya
`Kyrgyzstan
`Democratic People's
`Republic of Korea
`Republic of Korea
`Kazakstan
`Saint Lucia
`Liechtenstein
`Sri Lanka
`Liberia
`
`LS
`LT
`LU
`LV
`MC
`MD
`MG
`MK
`
`ML
`MN
`MR
`MW
`MX
`NE
`NL
`NO
`NZ
`PL
`PT
`RO
`RU
`SD
`SE
`SG
`
`Lesotho
`Lithuania
`Luxembourg
`Latvia
`Monaco
`Republic of Moldova
`Madagascar
`The fom1er Yugoslav
`Republic of Macedonia
`Mali
`Mongolia
`Mauritania
`Malawi
`Mexico
`Niger
`Netherlands
`Norway
`New Zealand
`Poland
`Portugal
`Romania
`Russian Federation
`Sudan
`Sweden
`Singapore
`
`SI
`SK
`SN
`sz
`TD
`TG
`TJ
`TM
`TR
`TT
`UA
`UG
`us
`uz
`VN
`YU
`zw
`
`Slovenia
`Slovakia
`Senegal
`Swaziland
`Chad
`Togo
`Tajikistan
`Turkmenistan
`Turkey
`Trinidad and Tobago
`Ukraine
`Uganda
`United States of America
`Uzbekistan
`Viet Nam
`Yugoslavia
`Zimbabwe
`
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`WO 98/29057
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`VALVE PROSTHESIS FOR IMPLANTATION IN BODY
`CHANNELS
`
`The present invention relates to a valve prosthesis for implantation
`in body channels, more particularly but not only to, cardiac valve prosthesis
`to be implanted by a transcutaneous catheterization technique.
`The valve prosthesis can be also applied to other body channels
`provided with native valves, such as veins or in organs (liver, intestine,
`urethra, ... ).
`The present invention also relates to a method for implanting a
`valve prosthesis, such as the valve according to the present invention.
`Implantable valves, which will be indifferently designated hereafter
`as "IV", "valve prosthesis" or "prosthetic valve", permits the reparation of a
`valvular defect by a less invasive technique in place of the usual surgical
`valve implantation which, in the case of valvular heart diseases, requires
`thoracotomy and extracorporeal circulation. A particular use for the IV
`concerns patients who cannot be operated on because of an associated
`disease or because of very old age or also patients who could be operated
`on but only at a very high risk.
`Although the IV of the present invention and the process for
`implanting said IV can be used in various heart valve diseases, the
`following description will first concern the aortic orifice in aortic stenosis,
`more particularly in its degenerative form in elderly patients.
`Aortic stenosis is a disease of the aortic valve in the left ventricle of
`the heart. The aortic valvular orifice is normally capable of opening during
`systole up to 4 to 6 cm2
`, therefore allowing free ejection of the ventricular
`blood volume into the aorta. This aortic valvular orifice can become tightly
`stenosed, and therefore the blood cannot anymore be freely ejected from
`the left ventricle. In fact, only a reduced amount of blood can be ejected by
`the left ventricle which has to markedly increase the intra-cavitary pressure
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`to force the stenosed aortic orifice. In such aortic diseases, the patients can
`have syncope, chest pain, and mainly difficulty in breathing. The evolution
`of such a disease is disastrous when symptoms of cardiac failure appear,
`since 50 % of the patients die in the year following the first symptoms of the
`disease.
`The only commonly available treatment is the replacement of the
`stenosed aortic valve by a prosthetic valve via surgery: this treatment
`moreover providing excellent results. If surgery is impossible to perform,
`i.e., if the patient is deemed inoperable or operable only at a too high
`surgical risk, an alternative possibility is to dilate the valve with a balloon
`catheter to enlarge the aortic orifice. Unfortunately, a good result is
`obtained only in about half of the cases and there is a high restenosis rate,
`i.e., about 80% after one year.
`Aortic stenosis is a very common disease in people above seventy
`years old and occurs more and more frequently as the subject gets older.
`As evidenced, the present tendency of the general evolution of the
`population is becoming older and older. Also, it can be evaluated, as a
`crude estimation, that about 30 to 50% of the subjects who are older than
`80 years and have a tight aortic stenosis, either cannot be operated on for
`aortic valve replacement with a reasonable surgical risk or even cannot be
`considered at all for surgery.
`It can be estimated that, about 30 to 40 persons out of a million per
`year, could benefit from an implantable aortic valve positioned by a
`catheterization technique. Until now, the implantation of a valve prosthesis
`for the treatment of aortic stenosis is considered unrealistic to perform
`since it is deemed difficult to superpose another valve such an implantable
`valve on the distorted stenosed native valve without excising the latter.
`From 1985, the technique of aortic valvuloplasty with a balloon
`catheter has been introduced for the treatment of subjects in whom surgery
`cannot be performed at all or which could be performed only with a
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`prohibitive surgical risk. Despite the considerable deformation of the
`stenosed aortic valve, commonly with marked calcification, it is often
`possible to enlarge significantly the aortic orifice by balloon inflation, . a
`procedure which is considered as low risk.
`However, this technique has been abandoned by most physicians
`because of the very high restenosis rate which occurs in about 80% of the
`patients within 10 to 12 months. Indeed, immediately after deflation of the
`balloon, a strong recoil phenomenon often produces a loss of half or even
`two thirds of the opening area obtained by the inflated balloon. For
`instance, inflation of a 20 mm diameter balloon in a stenosed aortic orifice
`of 0.5 cm2 area gives, when forcefully and fully inflated, an opening area
`equal to the cross sectionnal area of the maximally inflated balloon, i.e.,
`about 3 cm 2
`• However, measurements performed a few minutes after
`deflation and removal of the balloon have only an area around 1 cm2 to 1.2
`cm 2
`• This is due to the considerable recoil of the fibrous tissue of the
`diseased valve. The drawback in this procedure has also been clearly
`shown on fresh post mortem specimens.
`However, it is important to note that whereas the natural normal
`aortic valve is able to open with an orifice of about 5 to 6 cm2 and to
`accommodate a blood flow of more that 15 I/min. during heavy exercise for
`instance, an opening area of about 1.5 to 2 cm2 can accept a 6 to 8 I/min
`blood flow without a significant pressure gradient. Such a flow corresponds
`to the cardiac output of the elderly subject with limited physical activity.
`Therefore, an IV would not have to produce a large opening of the
`aortic orifice since an opening about 2 cm2 would be sufficient in most
`subjects, in particular in elderly subjects, whose cardiac output probably
`does not reach more than 6 to 8 I/min. during normal physical activity. For
`instance, the surgically implanted mechanical valves have an opening area
`which is far from the natural valve opening that ranges from 2 to 2.5 cm2
`
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`mainly because of the room taken by the large circular structure supporting
`the valvular part of the device.
`The prior art describes examples of cardiac valves prosthesis that
`are aimed at being implanted without surgical intervention by way of
`catheterization. For instance, US patent n° 5,411,552 describes a
`collapsible valve able to be introduced in the body in a compressed
`presentation and expanded in the right position by balloon inflation.
`Such valves, with a semi-lunar leaflet design, tend to imitate the
`natural valve. However, this type of design is inherently fragile, and such
`structures are not strong enough to be used in the case of aortic stenosis
`because of the strong recoil that will distort this weak structure and
`because they would not be able to resist the balloon inflation performed to
`position the implantable valve. Furthermore, this valvular structure is
`attached to a metallic frame of thin wires that will not be able to be tightly
`secured against the valve annulus. The metallic frame of this implantable
`valve is made of thin wires like in stents, which are implanted in vessels
`after balloon dilatation. Such a light stent structure is too weak to allow the
`implantable valve to be forcefully embedded into the aortic annulus.
`Moreover, there is a high risk of massive regurgitation (during the diastolic
`phase) through the spaces between the frame wires which is another
`prohibitive risk that would make this implantable valve impossible to use in
`clinical practice.
`Furthermore, an important point in view of the development of the
`IV is that it is possible to maximally inflate a balloon placed inside the
`compressed implantable valve to expand it and insert it in the stenosed
`aortic valve up to about 20 to 23 mm in diameter. At the time of maximum
`balloon inflation, the balloon is absolutely stiff and cylindrical without any
`waist. At that moment, the implantable valve is squeezed and crushed
`between the strong aortic annulus and the rigid balloon with the risk of
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`causing irreversible damage to the valvular structure of the implantable
`valve.
`SUMMARY OF THE INVENTION
`The invention is aimed to overcome these drawbacks and to
`implant an IV which will remain reliable for years.
`A particular aim of the present invention is to provide an IV,
`especially aimed at being used in case of aortic stenosis, which structure is
`capable of resisting the powerful recoil force and to stand the forceful
`balloon inflation performed to deploy the IV and to embed it in the aortic
`annulus.
`Another aim of the present invention is to provide an efficient
`prosthesis valve which can be implanted by a catheterization technique, in
`particular in a stenosed aortic orifice, taking advantage of the strong
`structure made of the distorted stenosed valve and of the large opening
`area produced by preliminary balloon inflation, performed as an initial step
`of the procedure.
`A further aim of the present invention is to provide an implantable
`valve which would not produce any risk of fluid regurgitation.
`A further aim of the present invention is to provide a valve
`prosthesis implantation technique using a two-balloon catheter and a two(cid:173)
`frame device.
`These aims are achieved according to the present invention which
`provides a valve prosthesis of the type mentioned in the introductory part
`and wherein said valve prosthesis comprises a collapsible continuous
`structure with guiding means providing stiffness and a frame to which said
`structure is fastened, said frame being strong enough to resist the recoil
`phenomenon of the fibrous tissue of the diseased valve.
`The IV, which is strongly embedded, enables the implantable valve
`to be maintained
`in
`the right position without any risk of further
`displacement, which would be a catastrophic event.
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`More precisely, this valvular structure comprises a valvular tissue
`compatible with the human body and blood, which is supple and resistant
`to allow said valvular structure to pass from a closed state to an open state
`to allow a body fluid, more particularly the blood, exerting pressure on said
`valvular structure, to flow. The valvular tissue forms a continuous surface
`and is provided with guiding means formed or incorporated within, creating
`stiffened zones which induce the valvular structure to follow a patterned
`movement from its open position to its closed state and vice-versa,
`providing therefore a structure sufficiently rigid to prevent diversion, in
`particular into the left ventricle and thus preventing any regurgitation of
`blood into the left ventricle in case of aortic implantation.
`Moreover, the guided structure of the IV of the invention allows the
`tissue of this structure to open and close with the same patterned
`movement while occupying as little space as possible in the closed state of
`the valve. Therefore, owing to these guiding means, the valvular structure
`withstands the unceasing movements under blood pressure changes
`during the heart beats.
`More preferably, the valvular structure has a substantially truncated
`hyperbolo'idal shape in its expanded position, with a larger base and a
`growing closer neck, ending in a smaller extremity forming the upper part of
`the valvular structure. The valvular structure has a curvature at its surface
`that is concave towards the aortic wall. Such a shape produces a strong
`and efficient structure in view of the systolo-diastolic movement of the
`valvular tissue. Such a valvular structure with its simple and regular shape
`also lowers the risk of being damaged by forceful balloon inflation at the
`time of IV deployment.
`A trunco-hyperbolo'idal shape with a small diameter at the upper
`extremity facilitates the closure of the valve at the beginning of diastole in
`initiating the starting of the reverse movement of the valvular tissue towards
`its base. Another advantage of this truncated hyperbolo'idal shape is that
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`the upper extremity of the valvular structure, because of its smaller
`diameter, remains at a distance from the coronary ostia during systole as
`well as during diastole, thus offering an additional security to ensure not to
`impede at all the passage of blood from the aorta to the coronary ostia.
`As another advantageous embodiment of the invention, the guiding
`means of the valvular structure are inclined strips from the base to the
`upper extremity of the valvular structure with regard to the central axis of
`the valvular structure. This inclination initiates and imparts a general
`helicoidal movement of the valvular structure around said central axis at the
`time of closure or opening of said structure, such a movement enabling to
`help initiate and finalize the closure of the valvular structure. In particular,
`this movement improves the collapse of the valvular structure towards its
`base at the time of diastole and during the reversal of flow at the very
`beginning of diastole. During diastole, the valvular structure thus falls down,
`folding on itself and collapses on its base, therefore closing the aortic
`orifice. The strips can be pleats, strenghthening struts or thickened zones.
`In other embodiments, said guiding means are rectilinear strips
`from the base to the upper extremity of the valvular structure. In this case,
`the guiding means can comprise pleats, struts or thickened zones. In a
`particular embodiment,
`the stiffened zones
`then created can be
`advantageously
`two main portions,
`trapezoidal
`in shape,
`formed
`symmetrically one to each other with regard to the central axis of the
`valvular structure, and two less rigid portions separating said two main
`portions to lead to a tight closeness in shape of a closed slot at the time of
`closure of the upper extremities of the main portions of the valvular
`structure. The thickened zones can be extended up to form the stiffened
`zones.
`
`More particularly, each of said main slightly rigid portions occupy
`approximately one third of the circumference of the valvular structure when
`this latter is in its open position. The slightly rigid portions maintain the
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`valvular structure closed during diastole by firmly applying themselves on
`each other. The closure of the valvular structure at the time of diastole thus
`does not have any tendency to collapse too much towards the aortic
`annulus.
`Preferably, the guiding means are a number of pleats formed within
`the tissue by folding, or formed by recesses or grooves made in the tissue.
`The shape of the pleats is adapted to achieve a global shape of the desired
`type for said position.
`Alternatively, the guiding means are made of strengthening struts,
`preferably at least three, incorporated in the tissue in combination or not
`with said pleats.
`The guiding means and, in particular, the strengthening struts, help
`to prevent the valvular tissue from collapsing back too much and to reverse
`inside the left ventricle through the base of the frame, preventing the risk of
`blood regurgitation.
`In a preferred prosthetic valve of the invention, said valvular tissue
`is made of synthetic biocompatible material such as Teflon® or Dacron®,
`polyethylene, polyamide, or made of biological material such as
`pericardium, porcine leaflets and the like. These materials are commonly
`used in cardiac surgery and are quite resistant, particularly to folding
`movements due to the inceasing systolo-diastolic movements of the
`valvular tissue and particularly at the junction with the frame of the
`implantable valve.
`The valvular structure is fastened along a substantial portion of an
`expandable frame, by sewing, by molding or by gluing to exhibit a tightness
`sufficiently hermetical to prevent any regurgitation of said body fluid
`between the frame and the valvular structure.
`Preferably, an internal cover is coupled or is integral to the valvular
`structure and placed between said valvular structure and the internal wall of
`the frame to prevent any passage of the body fluid through said frame.
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`Therefore, there is no regurgitation of blood as it would be the case if there
`were any space between the valvular structure fastened on the frame and
`the zone of application of the frame on the aortic annulus. The internal
`cover makes a sort of "sleeve" at least below the fastening of the valvular
`structure covering the internal surface of the frame and thus prevents any
`regurgitation of blood through the frame.
`In the present invention, the frame is a substantially cylindrical
`structure capable of maintaining said body channel open in its expanded
`state and supporting said collapsible valvular structure.
`In a preferred embodiment of the invention, the frame is made of a
`material which is distinguishable from biological tissue to be easily visible
`by non invasive imaging techniques.
`Preferably, said frame is a stainless metal structure or a fold able
`plastic material, made of intercrossing, preferably with rounded and smooth
`linear bars. This frame is strong enough to resist the recoil phenomenon of
`the fibrous tissue of the diseased valve. The size of the bars and their
`number are determined to give both the maximal rigidity when said frame is
`expanded and the smallest volume when the frame is compressed.
`More preferably, the frame has projecting curved extremities and
`presents a concave shape. This is aimed at reinforcing the embedding and
`the locking of the implantable valve in the distorted aortic orifice.
`In a preferred embodiment of the present invention, the IV is made
`in two parts, a first reinforced frame coupled with a second frame which is
`made of thinner bars than said first frame and which is embedded inside
`the second frame. This second frame to which the valvular structure is
`fastened as described above, is preferably less bulky than the first frame to
`occupy as little space as possible and to be easily expanded using low
`pressure balloon inflation.
`The present invention also relates to a double balloon catheter to
`separately position the first frame in the dilated stenosed aortic valve and
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`place the second frame that comprises the valvular structure. This catheter
`comprises two balloons fixed on a catheter shaft and separated by few
`centimeters.
`The first balloon is of the type sufficiently strong to avoid bursting
`s even at a very high pressure inflation and is aimed at carrying, in its
`deflated state, a strong frame aimed at scaffolding the previously dilated
`stenosed aortic valve. The second balloon is aimed at carrying the second
`frame with the valvular structure.
`An advantage of this double balloon catheter is that each balloon
`has an external diameter which is smaller than known balloons since each
`element to be expanded is smaller.
`Moreover, such a double balloon catheter allows to enlarge the
`choice for making an efficient valvular structure enabling to overcome the
`following two contradictory conditions:
`1) having a soft and mobile valvular structure capable of opening
`and closing freely in the blood stream, without risk of being damaged by
`balloon inflation; and
`2) needing a very strong structure able to resist the recoil force of
`the stenosed valve and capable of resisting, without any damage, a strong
`pressure inflation of the expanding balloon.
`Furthermore, the shaft of said double balloon catheter comprises
`two lumens for successive and separate inflation of each balloon. Of note,
`an additional lumen capable of allowing a rapid inflation takes additional
`room in the shaft.
`The invention also relates to a method of using a two-balloon
`catheter with a first frame and second frame to which a valve prosthesis of
`the type previously described is fastened.
`DESCRIPTION OF THE DRAWINGS
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`The invention will now be explained and other advantages and
`features will appear with reference to the accompanying schematical
`drawings wherein :
`- Figures 1 a, 1 b and 1 c illustrate, in section views, respectively, the
`normal aortic valve in systole, in diastole and a stenosed aortic valve;
`- Figures 2a and 2b illustrate two examples of a metallic frame
`which are combined to a valvular structure according to the present
`invention;
`- Figures 3a and 3b illustrate a frame according to the invention in
`its expanded position with an opening out of the extremities, respectively,
`with a cylindrical and a concave shape;
`- Figures 4a and b illustrate an IV of the invention respectively in its
`compressed position and in its expanded position in an open position as in
`systole;
`- Figures 5a and 5b illustrate respectively an IV of the invention in
`its closed position and a sectional view according to the central axis of such
`a valvular structure which is closed as in diastole;
`- Figures 6a to 6d illustrate a sectional view according to the central
`axis of an IV according to the present invention and showing the internal
`cover and the external cover of the valvular structure overlapping partially
`or non overlapping the frame bars;
`- Figure 7 illustrates the frontal zig-zag fastening line of the valvular
`tissue on the frame;
`- Figures Ba and 8b illustrate, respectively, a perspective view of a
`valvular structure and an internal cover made all of one piece and a
`perspective view of the corresponding frame into which they will be inserted
`and fastened;
`- Figures 9a and 9b illustrate inclined strengthening struts, an
`example of a valvular structure according to the invention, respectively in
`the open position and in the closed position;
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`- Figures 1 Oa and 1 Ob illustrate an example of a valvular structure
`comprising pleats, respectively in the open and in the closed position;
`- Figures 11 a and 11 b illustrate a valvular structure comprising two
`trapezo"idal slightly rigid portions, respectively in the open and in the closed
`position;
`
`Figures 11 c to 11 e illustrate a valvular structure comprising a
`rectangular stiffened zone, respectively in the open, intermediate and
`closed position;
`- Figures 12a and 12b illustrate, respectively, a perspective and
`cross sectional views of an
`implantable valve
`in
`its compressed
`presentation squeezed on a balloon catheter;
`- Figures 13a to 131 illustrate views of the successive procedure
`steps for the IV implantation in a stenosed aortic orifice;
`- Figure 14 illustrate an implantable valve made in two parts in its
`compressed presentation squeezed on a two-balloon catheter with a
`reinforced frame on a first balloon and with the implantable valve on the
`second balloon; and
`- Figures 15a to 15f illustrate the successive steps of the
`implantation of the implantation valve in two parts with a two-balloon
`catheter;
`DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
`In the diastole and systole illustrations of section views of Figures
`1 a and 1 b, the arrows A indicates the general direction of the blood flow.
`The semi-lunar leaflets 1 and 2 of a native aortic valve (with only two out of
`three shown here) are thin, supple and move easily from the completely
`open position (systole) to the closed position (diastole). The leaflets
`originate from an aortic annulus 2a.
`The leaflets 1' and 2' of a stenosed valve as illustrated in Figure 1 c,
`are thickened, distorted, calcified and more or less fused, leaving only a
`small hole or a narrow slit 3, which makes the ejection of blood from the left
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`ventricle cavity 4 into the aorta 5 difficult and limited. Figures 1 a to 1 c show
`also the coronary artery ostium 6a and 6b and Figure 1 a shows, in
`particular, the mitral valve 7 of the left ventricle cavity 4.
`An
`implantable valve according
`to
`the
`invention essentially
`comprises a supple valvular structure supported by a strong frame. The
`positioning of the implantable valve is an important point since the
`expanded frame has to be positioned exactly at the level of the native
`valvular leaflets 1, 2 of the native valve, the structures of which are pushed
`aside by the inflated balloon.
`Ideally, the implantable valve is positioned with the fastening line of
`the valvular structure on the frame exactly on the remains of the crushed
`stenosed valve to prevent any regurgitation of blood. In practice, it is
`difficult to position the implantable valve within less than 2 or 3 mm.
`However, any risk of regurgitation of blood is eliminated with the presence
`of an internal cover, as will be described below.
`The upper limit of the frame should be placed below the opening of
`the coronary arteries, i.e., the coronary ostia 6, or at their level so that the
`frame does not impede free blood flow in the coronary arteries. This point is
`a delicate part of positioning an IV since the distance between the superior
`limit of the leaflets of the natural valve and the coronary ostia 6 is only
`about 5 to 6 mm. However, the ostia are located in the Valsalva sinus 8
`which constitutes a hollow that are located a little out of the way. This helps
`to prevent from impeding the coronary blood flow by the IV.
`At the time of implantation, the operator evaluates the exact
`positioning of the coronary ostia by looking at the image produced by a
`sus-valvular angiogram with contrast
`injection performed before the
`implantation procedure. This image will be fixed in the same projection on a
`satellite TV screen and will permit the evaluation of the level of the origin of
`the right and left coronary arteries. Possibly, in case the ostia are not
`clearly seen by sus-valvular angiography, a thin guide wire, as those used
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`in coronary angioplasty, is positioned in each of the coronary arteries to
`serve as a marker of the coronary ostia.
`The lower part of the frame of the IV preferably extends by 2 or
`3 mm inside the left ventricle 4, below the aortic annulus 2a. However, this
`part of the frame should not reach the insertion of the septa! leaflet of the
`mitral valve 7, so that it does not interfere with its movements, particularly
`during diastole.
`Figures 2a and 2b show respectively an example of a cylindrical
`frame 10 comprising intercrossing linear bars 11 , with two intersections I by
`bar 11, the bars 11 being soldered or provided from a folded wire to
`constitute the frame, with for instance a 20 mm, 15 mm or 12 mm height,
`and an exampl~ with only one intersection of bars 11. Preferably, such a
`frame is expandable from a size of about 4 to 5 millimeters to a size of
`about 20 to 25 mm in diameter, or even to about 30-35 mm ( or more) in
`particular cases, for instance