CA2179263A1 - Stents for autologous tissue heart valve - Google Patents
Stents for autologous tissue heart valveInfo
- Publication number
- CA2179263A1 CA2179263A1 CA002179263A CA2179263A CA2179263A1 CA 2179263 A1 CA2179263 A1 CA 2179263A1 CA 002179263 A CA002179263 A CA 002179263A CA 2179263 A CA2179263 A CA 2179263A CA 2179263 A1 CA2179263 A1 CA 2179263A1
- Authority
- CA
- Canada
- Prior art keywords
- stent
- base
- posts
- covering
- outer stent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/24—Heart valves ; Vascular valves, e.g. venous valves; Heart implants, e.g. passive devices for improving the function of the native valve or the heart muscle; Transmyocardial revascularisation [TMR] devices; Valves implantable in the body
- A61F2/2412—Heart valves ; Vascular valves, e.g. venous valves; Heart implants, e.g. passive devices for improving the function of the native valve or the heart muscle; Transmyocardial revascularisation [TMR] devices; Valves implantable in the body with soft flexible valve members, e.g. tissue valves shaped like natural valves
- A61F2/2415—Manufacturing methods
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/24—Heart valves ; Vascular valves, e.g. venous valves; Heart implants, e.g. passive devices for improving the function of the native valve or the heart muscle; Transmyocardial revascularisation [TMR] devices; Valves implantable in the body
- A61F2/2409—Support rings therefor, e.g. for connecting valves to tissue
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/24—Heart valves ; Vascular valves, e.g. venous valves; Heart implants, e.g. passive devices for improving the function of the native valve or the heart muscle; Transmyocardial revascularisation [TMR] devices; Valves implantable in the body
- A61F2/2412—Heart valves ; Vascular valves, e.g. venous valves; Heart implants, e.g. passive devices for improving the function of the native valve or the heart muscle; Transmyocardial revascularisation [TMR] devices; Valves implantable in the body with soft flexible valve members, e.g. tissue valves shaped like natural valves
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/24—Heart valves ; Vascular valves, e.g. venous valves; Heart implants, e.g. passive devices for improving the function of the native valve or the heart muscle; Transmyocardial revascularisation [TMR] devices; Valves implantable in the body
- A61F2/2472—Devices for testing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S623/00—Prosthesis, i.e. artificial body members, parts thereof, or aids and accessories therefor
- Y10S623/90—Stent for heart valve
Abstract
An improved set of stents for autologous tissue heart valves is provided. The stents are designed with the aid of a computer-aided-design (CAD) system, and nest within each other to securely champ a piece of tissue which forms the leaflets of the heart valve. The geometrical features of the stents are designed to provide uniform nesting between the stents to prevent the formation of stress raisers on the tissue. Additionally, the windows in the stent posts are narrowed to prevent the suturing needle used during implantation of the valve from becoming lodged in the garter springs which clamp the outer stent to the inner stent. Finally, the sock covering the outer stent is bonded to the stent base at both upper and lower locations to isolate the bonds from the patient's blood flow.
Description
2 1 7 9 2 6 3 PCrlUS94114720 STENTS FOR Al~TOGLOGO~S TISSUE HEART VALVE
Backqround of the Invention _ =
This invention relates to the fabrication of bioprosthetic heart valve repl ~c 8 . Valve repl ~: -nt8 are required for p~t;~ntq having a heart valve which is I or otherwise incompetent. Commonly, heart valve bioprostheses are made from a combination of animal tissue and mechanical elements . These bioprostheses have, an advantage over purely mechanical valves in that they do not require the use of anticoagulant therapy that plagues purely mechanical valves .
U.S. Pat. No. 5,163,955 (the '955 patent) discloses such a bioprosthetic valve, in which an inner stent, on which the ti3sue used to construct the valve is wrapped, iB inserted into a spreadable outer stent ~ nt~;nln~ a self-adjusting tensioning spring around the circumference of its base. The inner stent posts are fitted with a plurality of outwardly-projecting pegs which register with holes cut in the tissue, and the inner stent assembly is covered with cloth. The Gpread outer stent clamps the stents together at its base and at a plurality of posts prajecting from the bases of both the inner and outer stents. This clamping thus secures the tissue while 1 ~ ~ting for irregularities and supplying a clamping force which is evenly distributed over the entire circumference of the tissue.
The outer stent disclosed in the ' 955 patent has an annular base constructed with a groove around its circumference, into which a self-adjusting tensioning means such as a garter spring is fitted. The garter spring provides a rl: ~ ;n~ force when the inner stent is inserted into the outer stent. Additionally, the posts on the outer stent are configured with windows ~ULL~U11ded by struts, which give shape to the post. The window is shaped to conform to the shape of the inner stent posts while leaving a small gap between the inner stent posts and the struts when the inner stent is inserted into the outer stent. Such an aLLdlly. -nt facilitates the insertion o~ the inner stent into the outer SUBSrl~lJTE S~!EET (RULE 2~
stent and provides for a uniform application o the clamping force to the ti9sue.
At the bottom of each of the windows in the outer stent posts are 910ts which segment the base into a plurality of arcuate portions. The slots enable the outer stent to be spread open so that it can easily be fitted over the inner stent without damaging the tissue during the valve assembly process .
An elastomeric sewing ring is bonded to the base of the outer stent assembly to facilitate the sewing o~ the assembled heart valve into the patient. The entire assembly is covered with a fabric cover, typically made out of DACRONn', which is bonded to the bottom of the outer stent base.
5 ry of the Invention - In accordance with the present invention, an improved outer stent is provided for a heart valve for securing an inner stent with a base and a plura~ity of posts PYtPntling and spaced around the base and having tissue wrapped thereon. The inner and outer stent3 cooperate to ~orm a heart valve implanted into a patient, typically by the use of sutures.
The outer stent has a base including a plurality of slots and preferably two tensioning springs disposed around the circumference of the base to prevent the inner and outer stents from hP~I ; n~ unsecured if one o~ the springs breaks .
The provision of more than one tensioning 3pring is an advantageous feature of the present invention which gives the valve redundancy, ~or if one spring breaks, another will continue to provide the outer stent's clamping force on the 3 o inner stent .
Additionally, the slots around the outer stent base are advantageously ~A~hi~nP~ to be narrow enough to decrease the potential for the suturing needle becoming entangled in the tensioning spring~ during the insertion procedure. Their width is selected to be the minimum sufficient to allow the outer stent to supply an adequate clamping force ii~ a small amount of tis3ue or debris becomes lodged in the slot.
AMENDED S~J~ET
. . . . .. .. ~ ~ .. .. . . .
2~ 79?~
.
The outer stent has a plurality o~ posts l-,~t~n~ing upwardly from its base connected to each other by scalloped portions and registering with the inner stent when the inner and outer stents are 9ecured together. The 3;osts each include a window to allow the registry of the corre9ponding inner stent posts with the outer stent. A further advantageous feature of the present invention is the provision of a wedge-shaped elastic ring bonded to the base o~ the outer 3tent to provide a better fit for the valve in the patient~s aortic root.
The geometry of the inner and outer stents is determined using three basic parameter3; the inner stent post width, the height of the scallops on the inner stent conneGting its posts, and the inner diameter of the valve. These parameters arG chosen based on the size required of the heart valve to be replaced. The chosen value5 for the5e parameters are then input into a computer-aided design (CAD) software package, which utilizes curve-fitting algorithms to generate three-dimensional surfaces corr~pr~nr9; n J to the inner stent blank .
Next, the outer stent geometry is derived from the curves developed during computation of the inner stent geometry. An important object of the outer stent geometry computation process i9 the provision of su~icient clearance between the inner and outer stents at all points to prevent the tissue 25 ~ from being too tightly clamped and forming stress raisers which increase the chances of fatigue tearing of the tissue.
The outer stent assembly is typically molde~L out of D13LRINra or another ~uitable thermoplastic and is covered by a fabric sock, typically of DACRON'Y. In the pre~erred ~mh~;m~.nt o~ the present invention, the sock is attached to the stent by first bonding it to the bottom sur~ace of the base of the outer stent at a first weld, then wrapping the covering around both the outer and inner surfaces of the outer stent, covering the base o~ the outer stent a secon~ time, and ~inally securing the other end of the sock to the top of the outer ~tent base with a second weld. This method oi~
construction is a significant feature of the present AME~nE~ SHEET
.. . . . . .. . . . .. . . . .. . ..
WO 95/16412 2 1 7 ~ 2 6 3 PCrrUS94/14720 provides two layers of fabric around the outside of the base of the outer stent . The outermost layer of f abric covers the first weld and thus keeps it out of the patiant's bloodstream, thereby preventing blood clots from forming on the weld and entering the patient ' 8 blood3tream . The extra layer also provides increa3ed strength for the valve base assembly by virtue of the double thickness it imparts to the cloth covering Along the Ces - c where the f abric covers the slots in the stent, the two layers of fabric covering the outer stent base are advantageously bonded together with a suitable adhesive. This is done to prevent a tunnel irom forming between the layers at points over the slots in the base; such a tunnel could serve as the for~-t;on point for blood clots.
The stent of the present invention therefore achieves the objects of providing a reliable securing force for the tissue mounted on the inner stent of a bioprosthetic heart valve while minimizing insertion difficulties and preventing the formation of blood clots.
~3rie Descri~tion of the ~awinC~
FIG. 1 is a perspective view of the major components in the valve assembly.
FIG. 2 is a view of the geometry of construction of the inner stent.
FIG. 3 is a wireframe view of a partially-constructed inner stent, particularly showing the scallop geometry.
FIG. 4 i8 a perspective view of a portion of the inner stent .
FIG. 5 is a partial cross-se~t;on~l view of a portion of an outer stent of the present invention.
FIG. 6 is a side view of the bare inner stent inserted into the outer stent.
FIG. 7 is a cutaway view of the inner and outer stents mated together/ showing the relevant clearances between the inner and outer stents.
FIG. 8 is a perspective view oi the mated Lnner and outer ~ . .
SUBSTITUTE SHEET (RULE 261 2 ~ 79263 stents .
FIG. 9 is an exploded view of the outer stent, securing springs, and covering sock of the pre9ent invention.
FIG. lO is a cross section of a post of the outer stent, showing part of the process of covering the outer stent with a f abric sock .
FIG. 11 i9 a cross section of a post of the outer stent when fully covered with a fabric sock, showing the bonding of the fabric to the surface of the outer stent.
FIG. 12 a side view illustrating the placement of adhesive between the fabric layers covering the outer stent.
Detailed DescriPtion of the Preferred ~o~im~ts The components which make up the assembled valve are illustrated in FIG. 1. As illustrated, these ~ omr~ne~ts include outer stent l, tissue 2, and inner stent 3. The inner and outer stents have fram~s, respectively constructed out of a thermoplastic such as DELRIN7' or the like using inj ection molding to form the entire component using u~ibody construGtion techniques, instead of welding or the like to attach any protuberances. Unibody construction is less risky to the patient than welding, since welded bonda can break more easily, leading to the injection of valve components or f ragments into the bloodstream .
Once constructed, the outer stent frame is integrated with other components, including a sewing ring and a plurality of garter springs or similar tensioning members, and both frames are covered with a fabric such as DACRO~i'M or the like, to form the completed inner and outer stents used in the vaive 3 o assembly .
The inner stent frame is preferably constructed with an annular base 12 with three posts 14, 16, and 18 extending from the annular base along the axis of the valve in the direction of blood flow through the valve. Preferably, three such posts are spaced uniformly around the annular b~se, i.e. such tha~
the centers of adjacent posts are separated by 120 degrees on a circle passing through all three. The po~its ~re conneGted AtAEl~ED SH~ET
.
21 79~3 by scalloped wall9, such as that illustrated at 20 The posts are configured with a plurality of outward-facing members 22.
These members are later shaped into tissue ~ j ~ t members for use in holding the tissue in place while the valve is being assembled. Finally, the inner stent is covered by a fabric sock made of DACRO~in' or a similar material, the sock being secured by bonding to the base of the inner stent Referring to ~I~. 5, the outer stent 1 ha3 a base 99, from which rise scalloped edges 90, which separate the outer stent posts, such as that shown at 92. The post 92 includes a strut 93 and has a window 94 cut out of it for receiving an inner stent post. At the bottom of the window are fillets 96 and slots 98 5~gTrl~nt;n~ the base of the outer stent into arcuate portions, such as 100. An important advantage of the present invention is that the slots 98 are made as thin as possible to minimize the risk that the sutures used in implanting the valve in the patient will become entangled in the securing springs located around the base of the outer stent. However, if the s~ots are made too thin, they may pinch the tissue and prevent the outer stent from supplying the clamping force necessary to hold the inner stent in place.
In practice, it has been ound that a width of 1. 27 mm is satisfactory clearance This width i9 approximately e~ual to twice the sum of the tissue and cover thickness.
The tissue 2 is preferably taken from the patient during the surgical procedure, and is preferably pericardium.
However, other type3 of tissue, such as autologous fascia lata or animal or cadaver tissue, may also be used as well After being harvested ~rom the patient, the tissue is immersed in a weak glutaraldehyde solution for a brief period of time, and is preferably cut into the proper shape using a die described in the ~ 955 patent. The current assignee' s PCT application entitled ~ISSUE CUTTINCi DIE, published ~June 22, 1995 as WO95/16409, discloses an improved tissue cutting die. The use of other means o~ cutting tke tissue, such as a scalpel, is also possible A~AENDED SHEET
The completed valve i8 asYembled by wrapping the tissue 2 around the inner stent 3, spreading open the outer stent 1, and inserting the inner stent into the outer stent. A
technique and tools for performing this operation are rlicrlnq~d in the present as8ignee'8 PCT application entitled ASSEMBLY TOOLING FOR AUTOLOGOUS TISSUE EIEART VALVE, published November 16, 1995 as W095/30387.
The design of the inner and outer stents must achieve several important obj ectives . Flrstly, the inner and outer stents should remain slightly separated from each other when mated. If they do not, the tissue wrapped on the inner stent will be pinched by the outer stent at the locations where they have insufficient separation, potentially resulting in fatigue tearing and failure of the tissue. Secondly, the tissue wrapped around the inner stent should form three spherically-shaped cusps to distribute the stresses of closure as evenly as possible over tha valve. Finally, the inner stent scallops on which the tissue rests should have a horizontal prof ile to prevent the formation of 9tress raiser9 at the points o contact between the tissue and the scallops.
The outer and inner stent5 are de5igned with a complex, three-dimensional shape corresponding to the desired valve size in order to achieve the5e goal5. The design is preferably carried out on a computer u5ing computer-aided design (CAD) software having the capability to represent three-dimensional obj acts . A5 described below, in tEle preferred l~mh~m~;mf.n~, the designer fir5t creates a basic geometry for the stentq and uses this to deine the scallop geometry. This scallop geometry i5 u5ed to split a rotational sur~ace created to define the stent blank, creating the proper shape for the stent in three dimension5. Necessary surfaces and illets are inalIy added to this shape to create the f inal stent shape . This shape is then input into machine tooling which cuts an electrode into the corresponding shape.
3 5 Finally, the electrode is used to dissolve a pattern into a block of a suitable metal, such as a nickel-~3teel alloy, into the f inal mold for inj ection-molding the stents .
AM~NDED SH~Er -: . . . . . . . .. .. ,, . _ .. ' . . ' ' . .. . .. . ! . . . .. -The basic geometry of the inner stent 3 is determined by three parameters d~p~onrlpn~ on the size and strength of the valve desired, namely the post width, the 9callop height above t~e base, and the inner diameter of the valve. The post width is determined from the strength desired for the inner stent and the requirement that the completed valve fully close. The post must be made wide enough to give the inner stent suf f icient strength but must not be made so wide that the amount of tissue draped over the inner stent posts is so great that the valve cannot properly close. Representative values for this dimension which have been found acceptable in practice for variously-sized valves are given in column K in Table 1.
The scallop height must be suf f icient to achieve three objective3: (1) allow the leaflets of the valve to completely close, (2) provide sufficient flexibility to absorb the shock of valve closure, and (3) distribute the stresses encountered duriny normal use of the valve evenly throughout the tissue leaflet area. The choice of the inner diameter of the valve is based on the size of the patient's annulus, as measured during the surgical procedure with an obturator such as that disclosed in the present assignee' s PCT application entitled HEART VALVE MEAsU~t~rl~:Nl TOOL, published ~une 22, 1995 as ~095/16410. Values for the scallop height as a ~unction of inner diameter which have been determined to be satisfactory in practice can be determined by subtracting dimension D in Table 1, which is the distance from the scallop base to the top of the inner stent posts, from the height of the inner stent, shown as dimension E in Table l.
3a An important advantage of the design r~ethodology of the present invention is that it allows the use of a single method to easily fabricate size-~pecific stent kits corresponding to varying annulus diameters. The parameters associated with each annulus diameter are easily input into the computer-aided de3ign ICAr~) software, which generates a corresponding stent geometry while requiring little user input.
Referring to FIG. 2, which illustrates the construction A~.~E~E~ .EET
.
2~ 79263 Wo 95/16412 PCr/US9S/14720 _g_ of the inner stent basic geometry from these parameters, the designer, typically operating on a computer having CAD
software, creates inner and outer circles 30 and 32 respectively in the x- z plane of the space in which the valve design will be created. A stent post prlmitive 34, which represents a cross section of the inner stent blank, is rotated about the y-axis to create the stent blank. The stent post primitive has a base section 36, which 3~as a taper, typically approximately 15 degrees, and an upper section 38, to which the outwardly-projecting members 22 are attached.
The upper section 38 is preferably parallel to the y axis.
The taper helps bias the valve into a closed position, which enables the valve to close more easily in low-pressure cnn~ ;nn~. It also produces a "jet nozzle~ effect which reduces turbulence as blood f lows through the valve, leading to a smaller net pressure drop across the valve and resulting in less energy loss to the cardiac cycle.
The stent post width is shown as dimension A in FIG. 2 and is drawn onto the annulus between the circles 30 and 32 at three equally-spaced intervals separated by 120 degrees, creating locations 37, 39, and 41, which represent the positions of the stent posts of the completed stent. In FIG
2, posts 37 and 41 are shown spaced 30 degrees each from the x-axis to facilitate understanding of the construction process described below. For each post, such as 37, a vector, such as that shown at 40, is drawn from a point 42 at the intersection of the post edge closest (in the x-direction) to the center of the circles and the circle 32, to a point 44 corresponding to the intersection of the post edge closest (in the x-direction~
3 0 to the center of the circles and the circle 3 0 .
This vector is projected onto the x axis, forming a line having endpoints 46 and 48. This procedure is repeated for post 41, resulting in a projection having l~n~roint~ 50 and 52.
The geometry of the scalloped edge separating posts 37 and 41 is ~l~t~n;n~ from the points 46, 48, 50, and 52 that result f rom the pro-j ection operations described above a~ f ollows:
vertical lines parallel to the y-axis, 54, 56, 58, and 60 are SUBSTITUlE SHEET (RULE 26~
Wo 95/16412 2 1 7 9 2 6 3 PCr/US94/14720 --10- ~
dropped from the respective points 46, 48, 50, and 52, and semicircles 62 and 64 are constructed to intersect, at their edges, the ~ines 50, 56, 54, and 60 respectively. The semicircles are constructed to be tangent to a line parallel to the x axis and spaced a distance ,~, the height of the scallop above the outer stent base, ~rom the base of the stent primitive. The union of these semicircle3 and their respective vertical lines forms curves which wil3~ be referred to hereinafter as splines 66 and 68. As will be seen, these splines, when projected onto the surface of ~rotation formed with the stent primitive, determine the shape of the scalloped edge separating posts 37 and 41. The pro~ection of vectors such as 40 onto the x-axis to create another vector lying in the x axis and having ~nrlrointR 46 and 48 is performed to ensure that the resulting splines, when projected onto the inner stent blank and ruled as described below, will form smooth surf aces intersecting the stent blank along their entire length. By rotating the inner stent about the y-axis by 120 degrees, an ;~l~nti~-Al procedure may be used to construct the other two splines.
As shown in FIG. 3, the three-dimensional solid model o the inner stent is created by revolving the inner stent post primitive 34 about the y-axis, thereby creating an inner surface 70 and an outer surface 72 of the inner stent. The inner spline 66 is then projected onto the inner surface 70 in three dimensions, and the outer spline 68 is pro~ ected onto the outer surface 72. The resulting spline curves 74 and 76 are thus flln-t;f-nq of all three spatial variables.
Next, a ruled surface 78 ~ nnf~rt;n~ splines 74 and 76 is created. This ruled surface may be transformed into a b-surface ~ ntA~n;ng many nodes by a suitable surface-fitting algorithm to more precisely define the scallop surface, if re~uired by the particular CAD system employed in the design process. The ruled surface 78 or a similar b-3urface represents the actual surface in space of the scallop connecting stent posts 37 and 41 and will eventually be sectioned out of the surface of revolution ~/~fin;n~ the solid SUBSmUTE S~tET lRULE 26~
Wo 95/16412 2 1 7 ~ 2 6 3 PCTIUS94/14720 model of the inner stent blank.
An important feature of the present invention is that the scallop profile i8 perp~on~;c~ to the axis of the stent, i . e . that a line connecting the inner and outer surfaces of the inner Etent along the surface rl.o~; n; ng the scallop is always parallel to the x-z plane at all positions along the scallop. This feature permits the tissue, which is draped over the scallops, to contact the inner stent along its entire width, thereby preventing the formation of possible points of fatigue on the tissue.
Another advantageous feature of the present invention i8 that the inner stent i8 designed so that CU8pS of the valve are spherical sections. The arcs 62 and 64 are chosen to be circular because such a geometry results in a spherical conf iguration f or each CU3p of the heart valve . This spherical conf iguration i8 important in ensuring ades~uate stress distribution throughout the tissue comprising the valve leaf lets .
After the creation of the ruled surface 78 between the stent posts 37 and 41, two other ruled surfaces constructed in an identical fashion to the ruled surface 78 are added between the other stent post 39 and the posts 37 and 41. These surfaces are used to form the scallops by splitting the solid model of the inner stent blank at their intersection with the solid inner stent model.
The ~;n;Flh~ three-dimensional model of the inner stent, which is output to programmable tooling, is created by deleting the L~ ;n;n~ surfaces and adding the fillets 80 and 82 to the inner stent posts, as shown in FIG. 4, to smooth the upper surfaces of each of the posts. The outward-facing tissue alignment members 22 are also added. Then, the ~,y~ hle tooling is used to fabricate an electrode having a shape corresponding to that output by the ~AD system. This electrode dissolves a pattern into a block of a suitable alloy into the proper shape to create the final injection mold for the inner stent.
The geometry of the outer stent l is determined much the SU~SrllV~E SHEEI ~RULÉ 2~
same way as that of the inner stent 3 in the pref erred pmho~im~n~ of the present invention. Referring to FIG. 5, the outer stent post primitive 84 is created with a tapered portion 86 and a vertical portion 88. The lower portion of the outer stent primitive i8 ~1; crl ;7r~.~1 outwardly a suitable distance, typically 0 . 5Q8 mm, from the location of the corresponding inner stent primitive 34, and the outer stent blank is revolved about the y-axis to create an outer stent solid model (not shown). A9 with the inner stent, the solid model is cut by calculated ruled or b-surfaces defining the scallops, and the required fillets are added to the final model. During the design of the external shape of the outer stent, the scalloped edges 90 are created somewhat differently f rom those of the inner stent, however .
An important objective in the design of the outer stent 1 is the maintenance of sufficient clearance between it and the inner stent 3 to prevent the tissue 2 wrapped around the inner stent from being pinched by the outer stent when the stents are mated together during the valve assembly process.
Such pinching could lead to the formation of stress raiser~ in the tissue and ultimately result in tearing of the valve tissue. Ag seen in FIGs. 6 and 7, unwanted pinching could occur, for example, in the radially-outward direction at the base of both stents at location 95, between the posts of the inner stent and the windows 9~ of the outer stent in both the radial and tangential directions at location 97, or anywhere in the volume formed between the inner and outer stents connecting these location3. It is thus important to provide sufficient clearance along the entire inner/outer stent mating region, which passes through these locations.
The outer stent design must also simultaneously achieve the objective of providing sufficient strength to the posts gz to withstand the wear the valve will be sub; ected to over the life of its user. Both of these objectives are advantageously 3s realizea by forming the window 94 into a spaded E;hape by including the fillet 96 and slightly deforming the ruled or b-surfaces used to create the inner stent scalloped edges to AMEND~D 51~
2 ~ 79263 contain a cusp, a6 ~3hown at numeral 90 in FIG. 8. The spaded window 6hape allows the outer stent posts to --int~in suf f icient clearance in both the tangential and radial directions with the inner stent posts and t-he tissue wrapped thereon, while the cusp-shaped scallop de9ign imparts sufficient thickness to each of the struts 93 to provide the required strength to each post 92.
While the above-described method for designing the shapes of the inner and outer stents has proven satisfactory, it will be understood that the use of other techniques to determine the scallop and post geometry is possible as well.
The clearance required between the inner and outer stents along the mating 6urfaces, as at locations 95 and 9~', is typically approximately O . 508 mm if a thin DACRO~7-~ sock is used to cover the inner and outer stents, and tissue having a thi~l~nG~:s of approximately 0.381 mm is used to ~abricate the valve. Such a value for the clearance also allows the tissue to penetrate the interstices of the DACRON~ cover, resulting in less slippage between the tissue and the stents. Other dimensions for the inner and outer stents are identified with the letters A-K in FIGs. 6 and 7. These dimensions are proportional to the size of the annulus to be fitted with the valve. Table 1 shows the preferable r(~1~ti-~nqhip between these dimensions (in millimeters, mm) and a variety of possible sizes of the an7 ulus to be ~itted:
SIZ~A D7A B DIA C DIA D B 1' ~3 )3 ,7 (~
301716.3 i2.7 12.2 7.5g 9.47 11.5 .55 .53 2.15 l.Z~
1915.0 25.2 13.7 B.59 10.6 12.9 .6~ .53 2.29 1.37 Z1lY.6 27.i 15.0 9.60 11.7 1~.0 .69 .55 2.3~ 2 2321.~ 30.~ 16.5 10.5 12.5 15.~ .76 .6~ 2.62 1.52 2523.2 32.~ 19.0 11.~ 13.~ 16.7 .8i .69 2.92 1.75 35T'OL. -1.02 ~1.02 -.127 1 .127 1 .127 1 .127 ~.05 -.05 . :~7 - :~7 Dc~ S'~
.... . . ..
2 i 79263 . ~
Other valve sizes are po9sible, such as valves configured for young children, where the annulu9 size might be as small as 14 mm.
The r~ cinnC in Table 1 have proven to be acceptable in practice, and allow the formation of 9pherical cusps, which have the advantages described above, from the tissue 2 in the completed valve.
Other features incorporated into the outer stent are illu6trated in FIG5. 10-11. In the preferred Pmhn~;rnPn~, the ba9e 99 of the outer 5tent is provided with a plurality of garter springs 102 or other securing members ~ct,~n~;n~ around the length of its base. The garter springs 102 provide the tension force which secure9 the inner and outer stents together. More than one garter spring is advantageously used in the present invention to increase the rF~ nrl~n~-y of the valve. If one garter spring breaks, the E~resence of another spring ensures that the outer 9tent is still able to fulfill its role of clamping the tissue around the inner stent. Such a result would not be possible if only one spring is used around the base of the outer stent.
Another advantageous feature of the present invention is the provision of a wedge-shaped sewing ring 104, which is attached to the annular base of the outer stent. The sewing ring 104 provides a site on the valve assembly for securing it into the patient~s annulus by use of sutures or similar means.
A wedge-shaped sewing ring has been found to fit better into the aortic root o a patient than other shapes when the valve is used as an aortic replacement.
As shown in FIGs. 9-12, the outer stent is covered with a DACRO~I~ sock 106. Covering the stent frame accomplishes the purpose of isolating nonbiological material, such as the stent frame thermoplastic, from the body. This also helps avoid the problem of thl . ' _..~olism, which occurs with the use of mechanical valves. It also accomplishes the purpose of promoti~.g tissue ingrowth into the interstices of the fabric, AMENDED SliFET
.. . . . . .
2~ 79263 . ~
to further isolate the nonbiological material from the body, and integrate the valve into the heart. Additionally, it accomplishes the purpose of providing an interface to the tissue clamped between the stent5 which is gentle, and which helps nourlsh the tissue and promote its viability by allowing f ree passage of blood to the tissue .
To cover the outer stent frame, first, a three-fingered DACRONTY sock is formed by heat seaming inner and outer sections of DACRON'Y fabric together utilizing either hot wire or ultrasonic techni~ues. Alternatively, the sock can be woven as one piece or sewn. The sock is then pulled over the outer stent frame and its outer section 107 is secured at the outer stent base at weld lD~. ~ext, the sock's inner section 109 is wrapped around the inner surface of the outer stent, as well as around the outer stent base itself. The inner layer is secured to the top of the base at a second weld 110. The use of these two welds on the outer stent base advantageously provides two layers of fabric covering ~Ytf~n~ling along the entire circumference of the outer stent base and thus increases the resilience of the base. Additionally, this method of securing the DACRON- sock also achieves the object of isolating the securing weld 103 from the patient~s bloodstream, minimizing the risk that blood clots would form on the weld and enter the patient' 5 bloodstream.
Along the portions of the outer stent base having slots, it is not possible to bond the inner section of the DACRON-sock 106 to the upper surface of the base 99. Nevertheless, it is desirable to bond the inner and outer sections of the sock to each other at these locations to prevent the separation of ~hese sections and the possibility of thromboemboli formation. Consec~uently, the present invention advantageously utilizes a medical-grade adhesive, such a3 RTV
silicone adhesive, to secure the outer and inner sections of the sock together along segments such as 112. Adhesive is applied to the inner or outer section along the portions of AMEN~ED S',E~
WO95/16412 PCrlUS9V14720 21 79263 -16- ~
the outer stent base overlyiny a slot.
While ~ ir~ntf~ and applications of this invention have been shown and described, it should be apparent to those skilled in the art that many more modifir~ir,n~ are possible wlthout departing from the scope o~ the present lnvention.
The invention is there~ore not to be restricted, except in the spirit o~ the appended claims.
SUBSTITUTE SHEET (RULE 2~
Backqround of the Invention _ =
This invention relates to the fabrication of bioprosthetic heart valve repl ~c 8 . Valve repl ~: -nt8 are required for p~t;~ntq having a heart valve which is I or otherwise incompetent. Commonly, heart valve bioprostheses are made from a combination of animal tissue and mechanical elements . These bioprostheses have, an advantage over purely mechanical valves in that they do not require the use of anticoagulant therapy that plagues purely mechanical valves .
U.S. Pat. No. 5,163,955 (the '955 patent) discloses such a bioprosthetic valve, in which an inner stent, on which the ti3sue used to construct the valve is wrapped, iB inserted into a spreadable outer stent ~ nt~;nln~ a self-adjusting tensioning spring around the circumference of its base. The inner stent posts are fitted with a plurality of outwardly-projecting pegs which register with holes cut in the tissue, and the inner stent assembly is covered with cloth. The Gpread outer stent clamps the stents together at its base and at a plurality of posts prajecting from the bases of both the inner and outer stents. This clamping thus secures the tissue while 1 ~ ~ting for irregularities and supplying a clamping force which is evenly distributed over the entire circumference of the tissue.
The outer stent disclosed in the ' 955 patent has an annular base constructed with a groove around its circumference, into which a self-adjusting tensioning means such as a garter spring is fitted. The garter spring provides a rl: ~ ;n~ force when the inner stent is inserted into the outer stent. Additionally, the posts on the outer stent are configured with windows ~ULL~U11ded by struts, which give shape to the post. The window is shaped to conform to the shape of the inner stent posts while leaving a small gap between the inner stent posts and the struts when the inner stent is inserted into the outer stent. Such an aLLdlly. -nt facilitates the insertion o~ the inner stent into the outer SUBSrl~lJTE S~!EET (RULE 2~
stent and provides for a uniform application o the clamping force to the ti9sue.
At the bottom of each of the windows in the outer stent posts are 910ts which segment the base into a plurality of arcuate portions. The slots enable the outer stent to be spread open so that it can easily be fitted over the inner stent without damaging the tissue during the valve assembly process .
An elastomeric sewing ring is bonded to the base of the outer stent assembly to facilitate the sewing o~ the assembled heart valve into the patient. The entire assembly is covered with a fabric cover, typically made out of DACRONn', which is bonded to the bottom of the outer stent base.
5 ry of the Invention - In accordance with the present invention, an improved outer stent is provided for a heart valve for securing an inner stent with a base and a plura~ity of posts PYtPntling and spaced around the base and having tissue wrapped thereon. The inner and outer stent3 cooperate to ~orm a heart valve implanted into a patient, typically by the use of sutures.
The outer stent has a base including a plurality of slots and preferably two tensioning springs disposed around the circumference of the base to prevent the inner and outer stents from hP~I ; n~ unsecured if one o~ the springs breaks .
The provision of more than one tensioning 3pring is an advantageous feature of the present invention which gives the valve redundancy, ~or if one spring breaks, another will continue to provide the outer stent's clamping force on the 3 o inner stent .
Additionally, the slots around the outer stent base are advantageously ~A~hi~nP~ to be narrow enough to decrease the potential for the suturing needle becoming entangled in the tensioning spring~ during the insertion procedure. Their width is selected to be the minimum sufficient to allow the outer stent to supply an adequate clamping force ii~ a small amount of tis3ue or debris becomes lodged in the slot.
AMENDED S~J~ET
. . . . .. .. ~ ~ .. .. . . .
2~ 79?~
.
The outer stent has a plurality o~ posts l-,~t~n~ing upwardly from its base connected to each other by scalloped portions and registering with the inner stent when the inner and outer stents are 9ecured together. The 3;osts each include a window to allow the registry of the corre9ponding inner stent posts with the outer stent. A further advantageous feature of the present invention is the provision of a wedge-shaped elastic ring bonded to the base o~ the outer 3tent to provide a better fit for the valve in the patient~s aortic root.
The geometry of the inner and outer stents is determined using three basic parameter3; the inner stent post width, the height of the scallops on the inner stent conneGting its posts, and the inner diameter of the valve. These parameters arG chosen based on the size required of the heart valve to be replaced. The chosen value5 for the5e parameters are then input into a computer-aided design (CAD) software package, which utilizes curve-fitting algorithms to generate three-dimensional surfaces corr~pr~nr9; n J to the inner stent blank .
Next, the outer stent geometry is derived from the curves developed during computation of the inner stent geometry. An important object of the outer stent geometry computation process i9 the provision of su~icient clearance between the inner and outer stents at all points to prevent the tissue 25 ~ from being too tightly clamped and forming stress raisers which increase the chances of fatigue tearing of the tissue.
The outer stent assembly is typically molde~L out of D13LRINra or another ~uitable thermoplastic and is covered by a fabric sock, typically of DACRON'Y. In the pre~erred ~mh~;m~.nt o~ the present invention, the sock is attached to the stent by first bonding it to the bottom sur~ace of the base of the outer stent at a first weld, then wrapping the covering around both the outer and inner surfaces of the outer stent, covering the base o~ the outer stent a secon~ time, and ~inally securing the other end of the sock to the top of the outer ~tent base with a second weld. This method oi~
construction is a significant feature of the present AME~nE~ SHEET
.. . . . . .. . . . .. . . . .. . ..
WO 95/16412 2 1 7 ~ 2 6 3 PCrrUS94/14720 provides two layers of fabric around the outside of the base of the outer stent . The outermost layer of f abric covers the first weld and thus keeps it out of the patiant's bloodstream, thereby preventing blood clots from forming on the weld and entering the patient ' 8 blood3tream . The extra layer also provides increa3ed strength for the valve base assembly by virtue of the double thickness it imparts to the cloth covering Along the Ces - c where the f abric covers the slots in the stent, the two layers of fabric covering the outer stent base are advantageously bonded together with a suitable adhesive. This is done to prevent a tunnel irom forming between the layers at points over the slots in the base; such a tunnel could serve as the for~-t;on point for blood clots.
The stent of the present invention therefore achieves the objects of providing a reliable securing force for the tissue mounted on the inner stent of a bioprosthetic heart valve while minimizing insertion difficulties and preventing the formation of blood clots.
~3rie Descri~tion of the ~awinC~
FIG. 1 is a perspective view of the major components in the valve assembly.
FIG. 2 is a view of the geometry of construction of the inner stent.
FIG. 3 is a wireframe view of a partially-constructed inner stent, particularly showing the scallop geometry.
FIG. 4 i8 a perspective view of a portion of the inner stent .
FIG. 5 is a partial cross-se~t;on~l view of a portion of an outer stent of the present invention.
FIG. 6 is a side view of the bare inner stent inserted into the outer stent.
FIG. 7 is a cutaway view of the inner and outer stents mated together/ showing the relevant clearances between the inner and outer stents.
FIG. 8 is a perspective view oi the mated Lnner and outer ~ . .
SUBSTITUTE SHEET (RULE 261 2 ~ 79263 stents .
FIG. 9 is an exploded view of the outer stent, securing springs, and covering sock of the pre9ent invention.
FIG. lO is a cross section of a post of the outer stent, showing part of the process of covering the outer stent with a f abric sock .
FIG. 11 i9 a cross section of a post of the outer stent when fully covered with a fabric sock, showing the bonding of the fabric to the surface of the outer stent.
FIG. 12 a side view illustrating the placement of adhesive between the fabric layers covering the outer stent.
Detailed DescriPtion of the Preferred ~o~im~ts The components which make up the assembled valve are illustrated in FIG. 1. As illustrated, these ~ omr~ne~ts include outer stent l, tissue 2, and inner stent 3. The inner and outer stents have fram~s, respectively constructed out of a thermoplastic such as DELRIN7' or the like using inj ection molding to form the entire component using u~ibody construGtion techniques, instead of welding or the like to attach any protuberances. Unibody construction is less risky to the patient than welding, since welded bonda can break more easily, leading to the injection of valve components or f ragments into the bloodstream .
Once constructed, the outer stent frame is integrated with other components, including a sewing ring and a plurality of garter springs or similar tensioning members, and both frames are covered with a fabric such as DACRO~i'M or the like, to form the completed inner and outer stents used in the vaive 3 o assembly .
The inner stent frame is preferably constructed with an annular base 12 with three posts 14, 16, and 18 extending from the annular base along the axis of the valve in the direction of blood flow through the valve. Preferably, three such posts are spaced uniformly around the annular b~se, i.e. such tha~
the centers of adjacent posts are separated by 120 degrees on a circle passing through all three. The po~its ~re conneGted AtAEl~ED SH~ET
.
21 79~3 by scalloped wall9, such as that illustrated at 20 The posts are configured with a plurality of outward-facing members 22.
These members are later shaped into tissue ~ j ~ t members for use in holding the tissue in place while the valve is being assembled. Finally, the inner stent is covered by a fabric sock made of DACRO~in' or a similar material, the sock being secured by bonding to the base of the inner stent Referring to ~I~. 5, the outer stent 1 ha3 a base 99, from which rise scalloped edges 90, which separate the outer stent posts, such as that shown at 92. The post 92 includes a strut 93 and has a window 94 cut out of it for receiving an inner stent post. At the bottom of the window are fillets 96 and slots 98 5~gTrl~nt;n~ the base of the outer stent into arcuate portions, such as 100. An important advantage of the present invention is that the slots 98 are made as thin as possible to minimize the risk that the sutures used in implanting the valve in the patient will become entangled in the securing springs located around the base of the outer stent. However, if the s~ots are made too thin, they may pinch the tissue and prevent the outer stent from supplying the clamping force necessary to hold the inner stent in place.
In practice, it has been ound that a width of 1. 27 mm is satisfactory clearance This width i9 approximately e~ual to twice the sum of the tissue and cover thickness.
The tissue 2 is preferably taken from the patient during the surgical procedure, and is preferably pericardium.
However, other type3 of tissue, such as autologous fascia lata or animal or cadaver tissue, may also be used as well After being harvested ~rom the patient, the tissue is immersed in a weak glutaraldehyde solution for a brief period of time, and is preferably cut into the proper shape using a die described in the ~ 955 patent. The current assignee' s PCT application entitled ~ISSUE CUTTINCi DIE, published ~June 22, 1995 as WO95/16409, discloses an improved tissue cutting die. The use of other means o~ cutting tke tissue, such as a scalpel, is also possible A~AENDED SHEET
The completed valve i8 asYembled by wrapping the tissue 2 around the inner stent 3, spreading open the outer stent 1, and inserting the inner stent into the outer stent. A
technique and tools for performing this operation are rlicrlnq~d in the present as8ignee'8 PCT application entitled ASSEMBLY TOOLING FOR AUTOLOGOUS TISSUE EIEART VALVE, published November 16, 1995 as W095/30387.
The design of the inner and outer stents must achieve several important obj ectives . Flrstly, the inner and outer stents should remain slightly separated from each other when mated. If they do not, the tissue wrapped on the inner stent will be pinched by the outer stent at the locations where they have insufficient separation, potentially resulting in fatigue tearing and failure of the tissue. Secondly, the tissue wrapped around the inner stent should form three spherically-shaped cusps to distribute the stresses of closure as evenly as possible over tha valve. Finally, the inner stent scallops on which the tissue rests should have a horizontal prof ile to prevent the formation of 9tress raiser9 at the points o contact between the tissue and the scallops.
The outer and inner stent5 are de5igned with a complex, three-dimensional shape corresponding to the desired valve size in order to achieve the5e goal5. The design is preferably carried out on a computer u5ing computer-aided design (CAD) software having the capability to represent three-dimensional obj acts . A5 described below, in tEle preferred l~mh~m~;mf.n~, the designer fir5t creates a basic geometry for the stentq and uses this to deine the scallop geometry. This scallop geometry i5 u5ed to split a rotational sur~ace created to define the stent blank, creating the proper shape for the stent in three dimension5. Necessary surfaces and illets are inalIy added to this shape to create the f inal stent shape . This shape is then input into machine tooling which cuts an electrode into the corresponding shape.
3 5 Finally, the electrode is used to dissolve a pattern into a block of a suitable metal, such as a nickel-~3teel alloy, into the f inal mold for inj ection-molding the stents .
AM~NDED SH~Er -: . . . . . . . .. .. ,, . _ .. ' . . ' ' . .. . .. . ! . . . .. -The basic geometry of the inner stent 3 is determined by three parameters d~p~onrlpn~ on the size and strength of the valve desired, namely the post width, the 9callop height above t~e base, and the inner diameter of the valve. The post width is determined from the strength desired for the inner stent and the requirement that the completed valve fully close. The post must be made wide enough to give the inner stent suf f icient strength but must not be made so wide that the amount of tissue draped over the inner stent posts is so great that the valve cannot properly close. Representative values for this dimension which have been found acceptable in practice for variously-sized valves are given in column K in Table 1.
The scallop height must be suf f icient to achieve three objective3: (1) allow the leaflets of the valve to completely close, (2) provide sufficient flexibility to absorb the shock of valve closure, and (3) distribute the stresses encountered duriny normal use of the valve evenly throughout the tissue leaflet area. The choice of the inner diameter of the valve is based on the size of the patient's annulus, as measured during the surgical procedure with an obturator such as that disclosed in the present assignee' s PCT application entitled HEART VALVE MEAsU~t~rl~:Nl TOOL, published ~une 22, 1995 as ~095/16410. Values for the scallop height as a ~unction of inner diameter which have been determined to be satisfactory in practice can be determined by subtracting dimension D in Table 1, which is the distance from the scallop base to the top of the inner stent posts, from the height of the inner stent, shown as dimension E in Table l.
3a An important advantage of the design r~ethodology of the present invention is that it allows the use of a single method to easily fabricate size-~pecific stent kits corresponding to varying annulus diameters. The parameters associated with each annulus diameter are easily input into the computer-aided de3ign ICAr~) software, which generates a corresponding stent geometry while requiring little user input.
Referring to FIG. 2, which illustrates the construction A~.~E~E~ .EET
.
2~ 79263 Wo 95/16412 PCr/US9S/14720 _g_ of the inner stent basic geometry from these parameters, the designer, typically operating on a computer having CAD
software, creates inner and outer circles 30 and 32 respectively in the x- z plane of the space in which the valve design will be created. A stent post prlmitive 34, which represents a cross section of the inner stent blank, is rotated about the y-axis to create the stent blank. The stent post primitive has a base section 36, which 3~as a taper, typically approximately 15 degrees, and an upper section 38, to which the outwardly-projecting members 22 are attached.
The upper section 38 is preferably parallel to the y axis.
The taper helps bias the valve into a closed position, which enables the valve to close more easily in low-pressure cnn~ ;nn~. It also produces a "jet nozzle~ effect which reduces turbulence as blood f lows through the valve, leading to a smaller net pressure drop across the valve and resulting in less energy loss to the cardiac cycle.
The stent post width is shown as dimension A in FIG. 2 and is drawn onto the annulus between the circles 30 and 32 at three equally-spaced intervals separated by 120 degrees, creating locations 37, 39, and 41, which represent the positions of the stent posts of the completed stent. In FIG
2, posts 37 and 41 are shown spaced 30 degrees each from the x-axis to facilitate understanding of the construction process described below. For each post, such as 37, a vector, such as that shown at 40, is drawn from a point 42 at the intersection of the post edge closest (in the x-direction) to the center of the circles and the circle 32, to a point 44 corresponding to the intersection of the post edge closest (in the x-direction~
3 0 to the center of the circles and the circle 3 0 .
This vector is projected onto the x axis, forming a line having endpoints 46 and 48. This procedure is repeated for post 41, resulting in a projection having l~n~roint~ 50 and 52.
The geometry of the scalloped edge separating posts 37 and 41 is ~l~t~n;n~ from the points 46, 48, 50, and 52 that result f rom the pro-j ection operations described above a~ f ollows:
vertical lines parallel to the y-axis, 54, 56, 58, and 60 are SUBSTITUlE SHEET (RULE 26~
Wo 95/16412 2 1 7 9 2 6 3 PCr/US94/14720 --10- ~
dropped from the respective points 46, 48, 50, and 52, and semicircles 62 and 64 are constructed to intersect, at their edges, the ~ines 50, 56, 54, and 60 respectively. The semicircles are constructed to be tangent to a line parallel to the x axis and spaced a distance ,~, the height of the scallop above the outer stent base, ~rom the base of the stent primitive. The union of these semicircle3 and their respective vertical lines forms curves which wil3~ be referred to hereinafter as splines 66 and 68. As will be seen, these splines, when projected onto the surface of ~rotation formed with the stent primitive, determine the shape of the scalloped edge separating posts 37 and 41. The pro~ection of vectors such as 40 onto the x-axis to create another vector lying in the x axis and having ~nrlrointR 46 and 48 is performed to ensure that the resulting splines, when projected onto the inner stent blank and ruled as described below, will form smooth surf aces intersecting the stent blank along their entire length. By rotating the inner stent about the y-axis by 120 degrees, an ;~l~nti~-Al procedure may be used to construct the other two splines.
As shown in FIG. 3, the three-dimensional solid model o the inner stent is created by revolving the inner stent post primitive 34 about the y-axis, thereby creating an inner surface 70 and an outer surface 72 of the inner stent. The inner spline 66 is then projected onto the inner surface 70 in three dimensions, and the outer spline 68 is pro~ ected onto the outer surface 72. The resulting spline curves 74 and 76 are thus flln-t;f-nq of all three spatial variables.
Next, a ruled surface 78 ~ nnf~rt;n~ splines 74 and 76 is created. This ruled surface may be transformed into a b-surface ~ ntA~n;ng many nodes by a suitable surface-fitting algorithm to more precisely define the scallop surface, if re~uired by the particular CAD system employed in the design process. The ruled surface 78 or a similar b-3urface represents the actual surface in space of the scallop connecting stent posts 37 and 41 and will eventually be sectioned out of the surface of revolution ~/~fin;n~ the solid SUBSmUTE S~tET lRULE 26~
Wo 95/16412 2 1 7 ~ 2 6 3 PCTIUS94/14720 model of the inner stent blank.
An important feature of the present invention is that the scallop profile i8 perp~on~;c~ to the axis of the stent, i . e . that a line connecting the inner and outer surfaces of the inner Etent along the surface rl.o~; n; ng the scallop is always parallel to the x-z plane at all positions along the scallop. This feature permits the tissue, which is draped over the scallops, to contact the inner stent along its entire width, thereby preventing the formation of possible points of fatigue on the tissue.
Another advantageous feature of the present invention i8 that the inner stent i8 designed so that CU8pS of the valve are spherical sections. The arcs 62 and 64 are chosen to be circular because such a geometry results in a spherical conf iguration f or each CU3p of the heart valve . This spherical conf iguration i8 important in ensuring ades~uate stress distribution throughout the tissue comprising the valve leaf lets .
After the creation of the ruled surface 78 between the stent posts 37 and 41, two other ruled surfaces constructed in an identical fashion to the ruled surface 78 are added between the other stent post 39 and the posts 37 and 41. These surfaces are used to form the scallops by splitting the solid model of the inner stent blank at their intersection with the solid inner stent model.
The ~;n;Flh~ three-dimensional model of the inner stent, which is output to programmable tooling, is created by deleting the L~ ;n;n~ surfaces and adding the fillets 80 and 82 to the inner stent posts, as shown in FIG. 4, to smooth the upper surfaces of each of the posts. The outward-facing tissue alignment members 22 are also added. Then, the ~,y~ hle tooling is used to fabricate an electrode having a shape corresponding to that output by the ~AD system. This electrode dissolves a pattern into a block of a suitable alloy into the proper shape to create the final injection mold for the inner stent.
The geometry of the outer stent l is determined much the SU~SrllV~E SHEEI ~RULÉ 2~
same way as that of the inner stent 3 in the pref erred pmho~im~n~ of the present invention. Referring to FIG. 5, the outer stent post primitive 84 is created with a tapered portion 86 and a vertical portion 88. The lower portion of the outer stent primitive i8 ~1; crl ;7r~.~1 outwardly a suitable distance, typically 0 . 5Q8 mm, from the location of the corresponding inner stent primitive 34, and the outer stent blank is revolved about the y-axis to create an outer stent solid model (not shown). A9 with the inner stent, the solid model is cut by calculated ruled or b-surfaces defining the scallops, and the required fillets are added to the final model. During the design of the external shape of the outer stent, the scalloped edges 90 are created somewhat differently f rom those of the inner stent, however .
An important objective in the design of the outer stent 1 is the maintenance of sufficient clearance between it and the inner stent 3 to prevent the tissue 2 wrapped around the inner stent from being pinched by the outer stent when the stents are mated together during the valve assembly process.
Such pinching could lead to the formation of stress raiser~ in the tissue and ultimately result in tearing of the valve tissue. Ag seen in FIGs. 6 and 7, unwanted pinching could occur, for example, in the radially-outward direction at the base of both stents at location 95, between the posts of the inner stent and the windows 9~ of the outer stent in both the radial and tangential directions at location 97, or anywhere in the volume formed between the inner and outer stents connecting these location3. It is thus important to provide sufficient clearance along the entire inner/outer stent mating region, which passes through these locations.
The outer stent design must also simultaneously achieve the objective of providing sufficient strength to the posts gz to withstand the wear the valve will be sub; ected to over the life of its user. Both of these objectives are advantageously 3s realizea by forming the window 94 into a spaded E;hape by including the fillet 96 and slightly deforming the ruled or b-surfaces used to create the inner stent scalloped edges to AMEND~D 51~
2 ~ 79263 contain a cusp, a6 ~3hown at numeral 90 in FIG. 8. The spaded window 6hape allows the outer stent posts to --int~in suf f icient clearance in both the tangential and radial directions with the inner stent posts and t-he tissue wrapped thereon, while the cusp-shaped scallop de9ign imparts sufficient thickness to each of the struts 93 to provide the required strength to each post 92.
While the above-described method for designing the shapes of the inner and outer stents has proven satisfactory, it will be understood that the use of other techniques to determine the scallop and post geometry is possible as well.
The clearance required between the inner and outer stents along the mating 6urfaces, as at locations 95 and 9~', is typically approximately O . 508 mm if a thin DACRO~7-~ sock is used to cover the inner and outer stents, and tissue having a thi~l~nG~:s of approximately 0.381 mm is used to ~abricate the valve. Such a value for the clearance also allows the tissue to penetrate the interstices of the DACRON~ cover, resulting in less slippage between the tissue and the stents. Other dimensions for the inner and outer stents are identified with the letters A-K in FIGs. 6 and 7. These dimensions are proportional to the size of the annulus to be fitted with the valve. Table 1 shows the preferable r(~1~ti-~nqhip between these dimensions (in millimeters, mm) and a variety of possible sizes of the an7 ulus to be ~itted:
SIZ~A D7A B DIA C DIA D B 1' ~3 )3 ,7 (~
301716.3 i2.7 12.2 7.5g 9.47 11.5 .55 .53 2.15 l.Z~
1915.0 25.2 13.7 B.59 10.6 12.9 .6~ .53 2.29 1.37 Z1lY.6 27.i 15.0 9.60 11.7 1~.0 .69 .55 2.3~ 2 2321.~ 30.~ 16.5 10.5 12.5 15.~ .76 .6~ 2.62 1.52 2523.2 32.~ 19.0 11.~ 13.~ 16.7 .8i .69 2.92 1.75 35T'OL. -1.02 ~1.02 -.127 1 .127 1 .127 1 .127 ~.05 -.05 . :~7 - :~7 Dc~ S'~
.... . . ..
2 i 79263 . ~
Other valve sizes are po9sible, such as valves configured for young children, where the annulu9 size might be as small as 14 mm.
The r~ cinnC in Table 1 have proven to be acceptable in practice, and allow the formation of 9pherical cusps, which have the advantages described above, from the tissue 2 in the completed valve.
Other features incorporated into the outer stent are illu6trated in FIG5. 10-11. In the preferred Pmhn~;rnPn~, the ba9e 99 of the outer 5tent is provided with a plurality of garter springs 102 or other securing members ~ct,~n~;n~ around the length of its base. The garter springs 102 provide the tension force which secure9 the inner and outer stents together. More than one garter spring is advantageously used in the present invention to increase the rF~ nrl~n~-y of the valve. If one garter spring breaks, the E~resence of another spring ensures that the outer 9tent is still able to fulfill its role of clamping the tissue around the inner stent. Such a result would not be possible if only one spring is used around the base of the outer stent.
Another advantageous feature of the present invention is the provision of a wedge-shaped sewing ring 104, which is attached to the annular base of the outer stent. The sewing ring 104 provides a site on the valve assembly for securing it into the patient~s annulus by use of sutures or similar means.
A wedge-shaped sewing ring has been found to fit better into the aortic root o a patient than other shapes when the valve is used as an aortic replacement.
As shown in FIGs. 9-12, the outer stent is covered with a DACRO~I~ sock 106. Covering the stent frame accomplishes the purpose of isolating nonbiological material, such as the stent frame thermoplastic, from the body. This also helps avoid the problem of thl . ' _..~olism, which occurs with the use of mechanical valves. It also accomplishes the purpose of promoti~.g tissue ingrowth into the interstices of the fabric, AMENDED SliFET
.. . . . . .
2~ 79263 . ~
to further isolate the nonbiological material from the body, and integrate the valve into the heart. Additionally, it accomplishes the purpose of providing an interface to the tissue clamped between the stent5 which is gentle, and which helps nourlsh the tissue and promote its viability by allowing f ree passage of blood to the tissue .
To cover the outer stent frame, first, a three-fingered DACRONTY sock is formed by heat seaming inner and outer sections of DACRON'Y fabric together utilizing either hot wire or ultrasonic techni~ues. Alternatively, the sock can be woven as one piece or sewn. The sock is then pulled over the outer stent frame and its outer section 107 is secured at the outer stent base at weld lD~. ~ext, the sock's inner section 109 is wrapped around the inner surface of the outer stent, as well as around the outer stent base itself. The inner layer is secured to the top of the base at a second weld 110. The use of these two welds on the outer stent base advantageously provides two layers of fabric covering ~Ytf~n~ling along the entire circumference of the outer stent base and thus increases the resilience of the base. Additionally, this method of securing the DACRON- sock also achieves the object of isolating the securing weld 103 from the patient~s bloodstream, minimizing the risk that blood clots would form on the weld and enter the patient' 5 bloodstream.
Along the portions of the outer stent base having slots, it is not possible to bond the inner section of the DACRON-sock 106 to the upper surface of the base 99. Nevertheless, it is desirable to bond the inner and outer sections of the sock to each other at these locations to prevent the separation of ~hese sections and the possibility of thromboemboli formation. Consec~uently, the present invention advantageously utilizes a medical-grade adhesive, such a3 RTV
silicone adhesive, to secure the outer and inner sections of the sock together along segments such as 112. Adhesive is applied to the inner or outer section along the portions of AMEN~ED S',E~
WO95/16412 PCrlUS9V14720 21 79263 -16- ~
the outer stent base overlyiny a slot.
While ~ ir~ntf~ and applications of this invention have been shown and described, it should be apparent to those skilled in the art that many more modifir~ir,n~ are possible wlthout departing from the scope o~ the present lnvention.
The invention is there~ore not to be restricted, except in the spirit o~ the appended claims.
SUBSTITUTE SHEET (RULE 2~
Claims (12)
1. An outer stent for securing an inner stent having a base and a plurality of posts extending therefrom and spaced around the base and tissue wrapped thereon, said outer stent spreadable from a relaxed position to a spread position, said outer and inner stents cooperating to form a heart valve implanted into a patient by use of sutures and needles, said outer stent comprising:
a base having a plurality of slots;
a plurality of tensioning springs disposed around said base to prevent said inner and outer stents from becoming unsecured if one of said springs breaks;
a plurality of posts extending upwardly from said base, each of said posts comprised of at least two struts and a window therebetween, said base forming a radial shoulder with respect to said posts;
an elastic ring disposed around said base for allowing the securing of said outer stent to said patient; and a covering emplaced around said base and said posts, said covering bonded to said base at a plurality of locations, said covering having two layers at said base to prevent bonds between said covering and said base from being directly in the bloodstream of said patient.
a base having a plurality of slots;
a plurality of tensioning springs disposed around said base to prevent said inner and outer stents from becoming unsecured if one of said springs breaks;
a plurality of posts extending upwardly from said base, each of said posts comprised of at least two struts and a window therebetween, said base forming a radial shoulder with respect to said posts;
an elastic ring disposed around said base for allowing the securing of said outer stent to said patient; and a covering emplaced around said base and said posts, said covering bonded to said base at a plurality of locations, said covering having two layers at said base to prevent bonds between said covering and said base from being directly in the bloodstream of said patient.
2. The outer stent of claim 1 wherein said covering is emplaced by bonding said covering to a bottom surface of said base of said outer stent at a first weld, wrapping said covering around both outer and inner surfaces of said outer stent and bonding said covering to an upper surface of said base of said outer stent at a second weld, said covering thereby having two layers along the entire circumference of said base of said outer stent.
3. The outer stent of claim 2 wherein said covering is bonded to itself with adhesive at points on said base of said outer stent where said covering overlies said slots in said base.
4. The outer stent of claim 1 wherein said elastic ring has a generally wedged shape.
5. The outer stent of claim 1 further comprising a plurality of scalloped portions disposed between said posts.
6. The outer stent of claim 5 wherein each of said scalloped portions contains a cusp at its midsection.
7. The outer stent of claim 1 wherein said posts and said base are shaped so as to prevent said tissue from being pinched when said inner stent has been inserted into said outer stent.
8. The outer stent of claim 1 wherein a width of said slots is approximately 1.27 mm.
9. The outer stent of claim 1 wherein said covering is seamless along an inner surface of said outer stent and along an upper part of an outer surface of said outer stent.
10. A method for constructing a stent for a heart valve, comprising the steps of:
creating a stent profile primitive;
rotating said stent profile primitive about a first axis to create a solid stent blank having inner and outer surfaces;
creating first and second splines;
forming a plurality of planes by connecting the intersection of said first spline with said inner surface of said solid stent blank with the intersection of said second spline with said outer surface of said solid stent blank at a plurality of locations displaced angularly along said first axis from each other an equal amount;
removing the material from said solid stent blank above each of said planes to form posts; and filleting said posts to provide a smooth upper surface for each of said posts.
creating a stent profile primitive;
rotating said stent profile primitive about a first axis to create a solid stent blank having inner and outer surfaces;
creating first and second splines;
forming a plurality of planes by connecting the intersection of said first spline with said inner surface of said solid stent blank with the intersection of said second spline with said outer surface of said solid stent blank at a plurality of locations displaced angularly along said first axis from each other an equal amount;
removing the material from said solid stent blank above each of said planes to form posts; and filleting said posts to provide a smooth upper surface for each of said posts.
11. The method of claim 10, wherein said planes are b-surfaces.
12. An inner stent having a base and a plurality of posts extending therefrom and spaced around said base, said posts connected by a plurality of scalloped edges, said scalloped edges having a profile perpendicular to the axis of said inner stent.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/169,336 US5755782A (en) | 1991-01-24 | 1993-12-17 | Stents for autologous tissue heart valve |
US08/169,336 | 1993-12-17 |
Publications (1)
Publication Number | Publication Date |
---|---|
CA2179263A1 true CA2179263A1 (en) | 1995-06-22 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002179263A Abandoned CA2179263A1 (en) | 1993-12-17 | 1994-12-16 | Stents for autologous tissue heart valve |
Country Status (6)
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---|---|
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EP (1) | EP0734236A1 (en) |
JP (1) | JPH09508537A (en) |
CA (1) | CA2179263A1 (en) |
TW (1) | TW249198B (en) |
WO (1) | WO1995016412A1 (en) |
Families Citing this family (110)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DK124690D0 (en) | 1990-05-18 | 1990-05-18 | Henning Rud Andersen | FAT PROTECTION FOR IMPLEMENTATION IN THE BODY FOR REPLACEMENT OF NATURAL FLEET AND CATS FOR USE IN IMPLEMENTING A SUCH FAT PROTECTION |
DE69432023T2 (en) * | 1993-09-10 | 2003-10-23 | Univ Queensland Santa Lucia | STEREOLITHOGRAPHIC ANATOMIC MODELING PROCESS |
US5865723A (en) * | 1995-12-29 | 1999-02-02 | Ramus Medical Technologies | Method and apparatus for forming vascular prostheses |
US6494904B1 (en) | 1996-12-27 | 2002-12-17 | Ramus Medical Technologies | Method and apparatus for forming vascular prostheses |
US5928281A (en) * | 1997-03-27 | 1999-07-27 | Baxter International Inc. | Tissue heart valves |
US6045576A (en) * | 1997-09-16 | 2000-04-04 | Baxter International Inc. | Sewing ring having increased annular coaptation |
US6250308B1 (en) | 1998-06-16 | 2001-06-26 | Cardiac Concepts, Inc. | Mitral valve annuloplasty ring and method of implanting |
US6159239A (en) * | 1998-08-14 | 2000-12-12 | Prodesco, Inc. | Woven stent/graft structure |
US6334873B1 (en) | 1998-09-28 | 2002-01-01 | Autogenics | Heart valve having tissue retention with anchors and an outer sheath |
US6162237A (en) * | 1999-04-19 | 2000-12-19 | Chan; Winston Kam Yew | Temporary intravascular stent for use in retrohepatic IVC or hepatic vein injury |
US6309417B1 (en) | 1999-05-12 | 2001-10-30 | Paul A. Spence | Heart valve and apparatus for replacement thereof |
US6348068B1 (en) * | 1999-07-23 | 2002-02-19 | Sulzer Carbomedics Inc. | Multi-filament valve stent for a cardisc valvular prosthesis |
AU6786400A (en) * | 1999-08-16 | 2001-03-13 | Citron Limited | Autologous tissue suture ring used in heart valve implantation |
US6491511B1 (en) | 1999-10-14 | 2002-12-10 | The International Heart Institute Of Montana Foundation | Mold to form stent-less replacement heart valves from biological membranes |
US6598307B2 (en) | 1999-11-17 | 2003-07-29 | Jack W. Love | Device and method for assessing the geometry of a heart valve |
US6709457B1 (en) * | 1999-11-24 | 2004-03-23 | St. Jude Medical, Inc. | Attachment of suture cuff to prosthetic heart valve |
NL1014095C2 (en) * | 2000-01-17 | 2001-07-18 | Cornelis Hendrikus Anna Witten | Implant valve for implantation into a blood vessel. |
US6454799B1 (en) * | 2000-04-06 | 2002-09-24 | Edwards Lifesciences Corporation | Minimally-invasive heart valves and methods of use |
US8366769B2 (en) | 2000-06-01 | 2013-02-05 | Edwards Lifesciences Corporation | Low-profile, pivotable heart valve sewing ring |
US6409758B2 (en) | 2000-07-27 | 2002-06-25 | Edwards Lifesciences Corporation | Heart valve holder for constricting the valve commissures and methods of use |
US7840393B1 (en) | 2000-10-04 | 2010-11-23 | Trivascular, Inc. | Virtual prototyping and testing for medical device development |
US7526112B2 (en) * | 2001-04-30 | 2009-04-28 | Chase Medical, L.P. | System and method for facilitating cardiac intervention |
US6425902B1 (en) | 2001-05-04 | 2002-07-30 | Cardiomend Llc | Surgical instrument for heart valve reconstruction |
US6893460B2 (en) | 2001-10-11 | 2005-05-17 | Percutaneous Valve Technologies Inc. | Implantable prosthetic valve |
US6755857B2 (en) | 2001-12-12 | 2004-06-29 | Sulzer Carbomedics Inc. | Polymer heart valve with perforated stent and sewing cuff |
US7201771B2 (en) | 2001-12-27 | 2007-04-10 | Arbor Surgical Technologies, Inc. | Bioprosthetic heart valve |
AU2003234505A1 (en) * | 2002-05-03 | 2003-11-17 | The General Hospital Corporation | Involuted endovascular valve and method of construction |
US7485141B2 (en) * | 2002-05-10 | 2009-02-03 | Cordis Corporation | Method of placing a tubular membrane on a structural frame |
US7270675B2 (en) * | 2002-05-10 | 2007-09-18 | Cordis Corporation | Method of forming a tubular membrane on a structural frame |
AU2003225291A1 (en) * | 2002-05-10 | 2003-11-11 | Cordis Corporation | Method of making a medical device having a thin wall tubular membrane over a structural frame |
US7351256B2 (en) * | 2002-05-10 | 2008-04-01 | Cordis Corporation | Frame based unidirectional flow prosthetic implant |
US7959674B2 (en) | 2002-07-16 | 2011-06-14 | Medtronic, Inc. | Suture locking assembly and method of use |
US8551162B2 (en) | 2002-12-20 | 2013-10-08 | Medtronic, Inc. | Biologically implantable prosthesis |
US7374488B2 (en) * | 2003-04-17 | 2008-05-20 | Atronic Systems G.M.B.H. | Player insert for a gaming machine, a gaming system and a method of operating a gaming system |
US8021421B2 (en) | 2003-08-22 | 2011-09-20 | Medtronic, Inc. | Prosthesis heart valve fixturing device |
US7556647B2 (en) | 2003-10-08 | 2009-07-07 | Arbor Surgical Technologies, Inc. | Attachment device and methods of using the same |
US7070616B2 (en) | 2003-10-31 | 2006-07-04 | Cordis Corporation | Implantable valvular prosthesis |
US7347869B2 (en) | 2003-10-31 | 2008-03-25 | Cordis Corporation | Implantable valvular prosthesis |
US7871435B2 (en) | 2004-01-23 | 2011-01-18 | Edwards Lifesciences Corporation | Anatomically approximate prosthetic mitral heart valve |
US20050228494A1 (en) * | 2004-03-29 | 2005-10-13 | Salvador Marquez | Controlled separation heart valve frame |
WO2005096988A1 (en) * | 2004-04-01 | 2005-10-20 | Cook Incorporated | A device for retracting the walls of a body vessel with remodelable material |
EP1737390A1 (en) * | 2004-04-08 | 2007-01-03 | Cook Incorporated | Implantable medical device with optimized shape |
US7318838B2 (en) * | 2004-12-31 | 2008-01-15 | Boston Scientific Scimed, Inc. | Smart textile vascular graft |
US8574257B2 (en) | 2005-02-10 | 2013-11-05 | Edwards Lifesciences Corporation | System, device, and method for providing access in a cardiovascular environment |
US7513909B2 (en) | 2005-04-08 | 2009-04-07 | Arbor Surgical Technologies, Inc. | Two-piece prosthetic valves with snap-in connection and methods for use |
EP1883375B1 (en) | 2005-05-24 | 2016-12-07 | Edwards Lifesciences Corporation | Rapid deployment prosthetic heart valve |
US8211169B2 (en) | 2005-05-27 | 2012-07-03 | Medtronic, Inc. | Gasket with collar for prosthetic heart valves and methods for using them |
US7682391B2 (en) * | 2005-07-13 | 2010-03-23 | Edwards Lifesciences Corporation | Methods of implanting a prosthetic mitral heart valve having a contoured sewing ring |
US20070027528A1 (en) * | 2005-07-29 | 2007-02-01 | Cook Incorporated | Elliptical implantable device |
US20070168022A1 (en) * | 2006-01-17 | 2007-07-19 | Eldridge Charles J | Heart valve |
US7967857B2 (en) | 2006-01-27 | 2011-06-28 | Medtronic, Inc. | Gasket with spring collar for prosthetic heart valves and methods for making and using them |
WO2007130881A2 (en) | 2006-04-29 | 2007-11-15 | Arbor Surgical Technologies, Inc. | Multiple component prosthetic heart valve assemblies and apparatus and methods for delivering them |
US8021161B2 (en) * | 2006-05-01 | 2011-09-20 | Edwards Lifesciences Corporation | Simulated heart valve root for training and testing |
US20080110810A1 (en) * | 2006-11-01 | 2008-05-15 | Raf Technology, Inc. | Mailpiece reject processing and labeling |
US20080177380A1 (en) * | 2007-01-19 | 2008-07-24 | Starksen Niel F | Methods and devices for heart tissue repair |
US8066755B2 (en) | 2007-09-26 | 2011-11-29 | Trivascular, Inc. | System and method of pivoted stent deployment |
US8663309B2 (en) | 2007-09-26 | 2014-03-04 | Trivascular, Inc. | Asymmetric stent apparatus and method |
US8226701B2 (en) | 2007-09-26 | 2012-07-24 | Trivascular, Inc. | Stent and delivery system for deployment thereof |
EP2194921B1 (en) | 2007-10-04 | 2018-08-29 | TriVascular, Inc. | Modular vascular graft for low profile percutaneous delivery |
US8328861B2 (en) | 2007-11-16 | 2012-12-11 | Trivascular, Inc. | Delivery system and method for bifurcated graft |
US8083789B2 (en) | 2007-11-16 | 2011-12-27 | Trivascular, Inc. | Securement assembly and method for expandable endovascular device |
US7846199B2 (en) | 2007-11-19 | 2010-12-07 | Cook Incorporated | Remodelable prosthetic valve |
PT3263070T (en) * | 2008-06-06 | 2020-01-07 | Edwards Lifesciences Corp | Low profile transcatheter heart valve |
US8449625B2 (en) | 2009-10-27 | 2013-05-28 | Edwards Lifesciences Corporation | Methods of measuring heart valve annuluses for valve replacement |
US8591567B2 (en) | 2008-11-25 | 2013-11-26 | Edwards Lifesciences Corporation | Apparatus and method for in situ expansion of prosthetic device |
US8308798B2 (en) | 2008-12-19 | 2012-11-13 | Edwards Lifesciences Corporation | Quick-connect prosthetic heart valve and methods |
US9980818B2 (en) | 2009-03-31 | 2018-05-29 | Edwards Lifesciences Corporation | Prosthetic heart valve system with positioning markers |
US8348998B2 (en) | 2009-06-26 | 2013-01-08 | Edwards Lifesciences Corporation | Unitary quick connect prosthetic heart valve and deployment system and methods |
FR2951549B1 (en) | 2009-10-15 | 2013-08-23 | Olivier Schussler | PROCESS FOR OBTAINING IMPLANTABLE MEDICAL BIOPROTHESES |
CN102883684B (en) | 2010-05-10 | 2015-04-08 | 爱德华兹生命科学公司 | Prosthetic heart valve |
US9554901B2 (en) | 2010-05-12 | 2017-01-31 | Edwards Lifesciences Corporation | Low gradient prosthetic heart valve |
US9125741B2 (en) | 2010-09-10 | 2015-09-08 | Edwards Lifesciences Corporation | Systems and methods for ensuring safe and rapid deployment of prosthetic heart valves |
US9370418B2 (en) | 2010-09-10 | 2016-06-21 | Edwards Lifesciences Corporation | Rapidly deployable surgical heart valves |
US8641757B2 (en) | 2010-09-10 | 2014-02-04 | Edwards Lifesciences Corporation | Systems for rapidly deploying surgical heart valves |
US8845720B2 (en) | 2010-09-27 | 2014-09-30 | Edwards Lifesciences Corporation | Prosthetic heart valve frame with flexible commissures |
US8690764B2 (en) | 2010-10-20 | 2014-04-08 | Covidien Lp | Endoscope cleaner |
US20120116496A1 (en) | 2010-11-05 | 2012-05-10 | Chuter Timothy A | Stent structures for use with valve replacements |
GB2488530A (en) * | 2011-02-18 | 2012-09-05 | David J Wheatley | Heart valve |
US8945209B2 (en) | 2011-05-20 | 2015-02-03 | Edwards Lifesciences Corporation | Encapsulated heart valve |
US9078747B2 (en) | 2011-12-21 | 2015-07-14 | Edwards Lifesciences Corporation | Anchoring device for replacing or repairing a heart valve |
US10940167B2 (en) * | 2012-02-10 | 2021-03-09 | Cvdevices, Llc | Methods and uses of biological tissues for various stent and other medical applications |
US8992595B2 (en) | 2012-04-04 | 2015-03-31 | Trivascular, Inc. | Durable stent graft with tapered struts and stable delivery methods and devices |
US9498363B2 (en) | 2012-04-06 | 2016-11-22 | Trivascular, Inc. | Delivery catheter for endovascular device |
US11007058B2 (en) | 2013-03-15 | 2021-05-18 | Edwards Lifesciences Corporation | Valved aortic conduits |
SG11201506352SA (en) | 2013-03-15 | 2015-09-29 | Edwards Lifesciences Corp | Valved aortic conduits |
US9468527B2 (en) | 2013-06-12 | 2016-10-18 | Edwards Lifesciences Corporation | Cardiac implant with integrated suture fasteners |
US9919137B2 (en) | 2013-08-28 | 2018-03-20 | Edwards Lifesciences Corporation | Integrated balloon catheter inflation system |
CN105263445B (en) | 2013-09-20 | 2018-09-18 | 爱德华兹生命科学公司 | Heart valve with increased effective orifice area |
US20150122687A1 (en) | 2013-11-06 | 2015-05-07 | Edwards Lifesciences Corporation | Bioprosthetic heart valves having adaptive seals to minimize paravalvular leakage |
US9549816B2 (en) | 2014-04-03 | 2017-01-24 | Edwards Lifesciences Corporation | Method for manufacturing high durability heart valve |
US9585752B2 (en) | 2014-04-30 | 2017-03-07 | Edwards Lifesciences Corporation | Holder and deployment system for surgical heart valves |
USD867594S1 (en) | 2015-06-19 | 2019-11-19 | Edwards Lifesciences Corporation | Prosthetic heart valve |
CA2914094C (en) | 2014-06-20 | 2021-01-05 | Edwards Lifesciences Corporation | Surgical heart valves identifiable post-implant |
US10456246B2 (en) | 2015-07-02 | 2019-10-29 | Edwards Lifesciences Corporation | Integrated hybrid heart valves |
WO2017004369A1 (en) | 2015-07-02 | 2017-01-05 | Edwards Lifesciences Corporation | Hybrid heart valves adapted for post-implant expansion |
ITUB20152409A1 (en) | 2015-07-22 | 2017-01-22 | Sorin Group Italia Srl | VALVE SLEEVE FOR VALVULAR PROSTHESIS AND CORRESPONDING DEVICE |
CN106980729B (en) * | 2015-07-24 | 2018-08-17 | 安徽工业大学 | A kind of continuous casting breakout prediction method based on mixed model |
CA2995855C (en) | 2015-09-02 | 2024-01-30 | Edwards Lifesciences Corporation | Spacer for securing a transcatheter valve to a bioprosthetic cardiac structure |
US10080653B2 (en) | 2015-09-10 | 2018-09-25 | Edwards Lifesciences Corporation | Limited expansion heart valve |
US10667904B2 (en) | 2016-03-08 | 2020-06-02 | Edwards Lifesciences Corporation | Valve implant with integrated sensor and transmitter |
US10456245B2 (en) | 2016-05-16 | 2019-10-29 | Edwards Lifesciences Corporation | System and method for applying material to a stent |
USD846122S1 (en) | 2016-12-16 | 2019-04-16 | Edwards Lifesciences Corporation | Heart valve sizer |
WO2018144461A1 (en) * | 2017-01-31 | 2018-08-09 | The Board Of Regents Of The University Of Oklahoma | Animal wound model and methods of use |
US10463485B2 (en) | 2017-04-06 | 2019-11-05 | Edwards Lifesciences Corporation | Prosthetic valve holders with automatic deploying mechanisms |
CN110662511B (en) | 2017-04-28 | 2022-03-29 | 爱德华兹生命科学公司 | Prosthetic heart valve with collapsible retainer |
WO2019147497A1 (en) | 2018-01-23 | 2019-08-01 | Edwards Lifesciences Corporation | Prosthetic valve holders, systems, and methods |
USD908874S1 (en) | 2018-07-11 | 2021-01-26 | Edwards Lifesciences Corporation | Collapsible heart valve sizer |
US11412921B2 (en) | 2018-10-02 | 2022-08-16 | Covidien Lp | Multi lumen access device |
US11357542B2 (en) | 2019-06-21 | 2022-06-14 | Covidien Lp | Valve assembly and retainer for surgical access assembly |
EP4076284A1 (en) | 2019-12-16 | 2022-10-26 | Edwards Lifesciences Corporation | Valve holder assembly with suture looping protection |
Family Cites Families (46)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1266423A (en) * | 1917-07-26 | 1918-05-14 | Charles Frederick Denise | Device for holding strainers over cream-separators. |
FR766025A (en) * | 1933-09-16 | 1934-06-20 | Masch Ind A G Johann Klinger | Automatic hose clamp |
US2708950A (en) * | 1953-04-13 | 1955-05-24 | P T Mcdonough | Pipe end cover and protector |
US2822819A (en) * | 1953-08-07 | 1958-02-11 | Geeraert Corp | Cuspate check valve |
US3022802A (en) * | 1954-11-08 | 1962-02-27 | Harvey M Lewis | Reenforced hollow circular plastic objects |
GB1189399A (en) * | 1967-08-05 | 1970-04-22 | Amis | Non-Return Valve |
GB1264471A (en) * | 1968-01-12 | 1972-02-23 | ||
US3548418A (en) * | 1968-05-03 | 1970-12-22 | Cutter Lab | Graft valve transplantation for human hearts and graft-support ring therefor |
US3570014A (en) * | 1968-09-16 | 1971-03-16 | Warren D Hancock | Stent for heart valve |
US3532016A (en) * | 1968-10-18 | 1970-10-06 | Warren Zeph Lane | Method and apparatus for cutting autogenous tissue for cardiac valve repair |
GB1264472A (en) * | 1969-09-25 | 1972-02-23 | ||
US3714671A (en) * | 1970-11-30 | 1973-02-06 | Cutter Lab | Tissue-type heart valve with a graft support ring or stent |
US3755823A (en) * | 1971-04-23 | 1973-09-04 | Hancock Laboratories Inc | Flexible stent for heart valve |
DE2129071C3 (en) * | 1971-06-11 | 1974-11-21 | Linde Ag, 6200 Wiesbaden | Process for the production of a multi-layer vacuum insulation for pipes |
US4192020A (en) * | 1975-05-07 | 1980-03-11 | Washington University | Heart valve prosthesis |
US4035849A (en) * | 1975-11-17 | 1977-07-19 | William W. Angell | Heart valve stent and process for preparing a stented heart valve prosthesis |
CA1069652A (en) * | 1976-01-09 | 1980-01-15 | Alain F. Carpentier | Supported bioprosthetic heart valve with compliant orifice ring |
US4084268A (en) * | 1976-04-22 | 1978-04-18 | Shiley Laboratories, Incorporated | Prosthetic tissue heart valve |
AT352482B (en) * | 1977-01-14 | 1979-09-25 | Danescu Septimius Dipl Archite | DEVICE FOR CONNECTING PROFILE BARS |
US4297749A (en) * | 1977-04-25 | 1981-11-03 | Albany International Corp. | Heart valve prosthesis |
US4172295A (en) * | 1978-01-27 | 1979-10-30 | Shiley Scientific, Inc. | Tri-cuspid three-tissue prosthetic heart valve |
US4247292A (en) * | 1979-06-06 | 1981-01-27 | Angell William W | Natural tissue heart valve fixation process |
US4388735A (en) * | 1980-11-03 | 1983-06-21 | Shiley Inc. | Low profile prosthetic xenograft heart valve |
US4478661A (en) * | 1981-03-20 | 1984-10-23 | Dayco Corporation | Method of making a reinforced collapsible hose construction |
US4470157A (en) * | 1981-04-27 | 1984-09-11 | Love Jack W | Tricuspid prosthetic tissue heart valve |
US4501030A (en) * | 1981-08-17 | 1985-02-26 | American Hospital Supply Corporation | Method of leaflet attachment for prosthetic heart valves |
US4427470A (en) * | 1981-09-01 | 1984-01-24 | University Of Utah | Vacuum molding technique for manufacturing a ventricular assist device |
ATE21330T1 (en) * | 1982-01-20 | 1986-08-15 | Martin Morris Black | ARTIFICIAL HEART VALVES. |
US4597767A (en) * | 1982-12-15 | 1986-07-01 | Andrew Lenkei | Split leaflet heart valve |
SU1116573A1 (en) * | 1983-01-07 | 1985-07-15 | Предприятие П/Я А-1619 | Bioprosthesis of heart valve |
GB8300636D0 (en) * | 1983-01-11 | 1983-02-09 | Black M M | Heart valve replacements |
US4512471A (en) * | 1984-04-06 | 1985-04-23 | Angicor Limited | Storage unit |
GB8424582D0 (en) * | 1984-09-28 | 1984-11-07 | Univ Glasgow | Heart valve prosthesis |
US4725274A (en) * | 1986-10-24 | 1988-02-16 | Baxter Travenol Laboratories, Inc. | Prosthetic heart valve |
US4851000A (en) * | 1987-07-31 | 1989-07-25 | Pacific Biomedical Holdings, Ltd. | Bioprosthetic valve stent |
US4838288A (en) * | 1988-03-14 | 1989-06-13 | Pioneering Technologies, Inc. | Heart valve and xenograft washing system |
US5036312A (en) * | 1989-01-03 | 1991-07-30 | Motorola, Inc. | Spring failure detection and safety system |
US5060716A (en) * | 1989-03-31 | 1991-10-29 | Heine William F | Heat dissipating device and combination including same |
US5037434A (en) * | 1990-04-11 | 1991-08-06 | Carbomedics, Inc. | Bioprosthetic heart valve with elastic commissures |
US5147391A (en) * | 1990-04-11 | 1992-09-15 | Carbomedics, Inc. | Bioprosthetic heart valve with semi-permeable commissure posts and deformable leaflets |
US5197979A (en) * | 1990-09-07 | 1993-03-30 | Baxter International Inc. | Stentless heart valve and holder |
JP3049096B2 (en) * | 1990-12-20 | 2000-06-05 | 株式会社リコー | Fillet surface generation method between curved surfaces |
US5163955A (en) * | 1991-01-24 | 1992-11-17 | Autogenics | Rapid assembly, concentric mating stent, tissue heart valve with enhanced clamping and tissue alignment |
EP0583316B1 (en) * | 1991-05-08 | 1996-12-11 | Nika Health Products Limited | Process and apparatus for the production of a heart valve prosthesis |
US5401257A (en) * | 1993-04-27 | 1995-03-28 | Boston Scientific Corporation | Ureteral stents, drainage tubes and the like |
US5480424A (en) * | 1993-11-01 | 1996-01-02 | Cox; James L. | Heart valve replacement using flexible tubes |
-
1993
- 1993-12-17 US US08/169,336 patent/US5755782A/en not_active Expired - Lifetime
-
1994
- 1994-06-17 TW TW083105524A patent/TW249198B/en active
- 1994-12-16 WO PCT/US1994/014720 patent/WO1995016412A1/en not_active Application Discontinuation
- 1994-12-16 JP JP7517023A patent/JPH09508537A/en active Pending
- 1994-12-16 CA CA002179263A patent/CA2179263A1/en not_active Abandoned
- 1994-12-16 EP EP95906050A patent/EP0734236A1/en not_active Withdrawn
-
1995
- 1995-06-06 US US08/475,030 patent/US5612885A/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
WO1995016412A1 (en) | 1995-06-22 |
TW249198B (en) | 1995-06-11 |
US5612885A (en) | 1997-03-18 |
US5755782A (en) | 1998-05-26 |
EP0734236A1 (en) | 1996-10-02 |
JPH09508537A (en) | 1997-09-02 |
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Legal Events
Date | Code | Title | Description |
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FZDE | Discontinued |