CA1163054A - Artificial heart valve - Google Patents
Artificial heart valveInfo
- Publication number
- CA1163054A CA1163054A CA000376177A CA376177A CA1163054A CA 1163054 A CA1163054 A CA 1163054A CA 000376177 A CA000376177 A CA 000376177A CA 376177 A CA376177 A CA 376177A CA 1163054 A CA1163054 A CA 1163054A
- Authority
- CA
- Canada
- Prior art keywords
- leaflet
- heart valve
- guide
- lateral
- valve according
- 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.)
- Expired
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Abstract
A prosthetic heart valve has at least one occluder leaflet in which lateral extensions on each leaflet are insertable into generally trapezoidal or triangular depressions formed in diametrically opposed extension walls of the valve body and which depressions both guide and limit the opening and closing movement of each leaflet through predetermined angles of movement.
Description
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This invention relates to valves and more par-ticularly relates to artificial heart valves which can be transplanted into the mitral, aortic, tricuspid or pulmo-nic portions of the heart.
Numerous types of prosthetic heart valves have been devised to the end of replacing defective natural heart valves and to simulate as closely as possible the operation Gf natural heart valves. Essentially, the natural valves in the human heart operate as check valves which are capable of operating between open and closed positions in response to the flow of blood to and from the heart. As disclosed in prior copending application for patent, Serial ~o. 84,318, filed 12 October, 19~9, now U.S.
Letters Patent No. 4,363,142, granted 14 October, 1982, and assigned to the assignee of this application, it is essen-tial that the artificial heart valve be capable of achieving the ra~pid response time of the natural heart valve to the reverse flow of blood in moving between the open and closed positions. Moreover, the valve should be capable of achieving a maximum opening to an angle in excess of 60~ to the transverse axis of the valve for the passage of blood with a minimum of turbulence. Further, the valve must have a low profile or height so as to pre-vent any possible interference with the ventricular septum as well as to minimize aortic obstruction and low cardiac output. In this same relation, it is equally important that there be a low pressure gradient between the upstream and downstream ends of the valve when the valve is in its open position. For instance, a pressure gradient on -the order of 20 millimeters to 50 millimeters of mercury in a natural heart valve is symptomatic of defective func-tioning of the valve; whereas, the pressure gradient or ~3 -- 1 -- !
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drop of a properly func-tioning valve should be less -than 10 millimeters of mercury~
Previously, U.S. Letters Patent ~o. 3,589,392 emplo~ed curved leaflets which were hinged to a valve body for pivotal movement between the open and closed positions. ~ore recently, the hereinbefore referred to copending application for patent was directed to a novel and improved form of guide assembly which is especially adapted for curved leaflets 50 as to directionally control the mov~ment of the leaflets in response to the direction of liquid or blood flow therethrough, -the guide assembly including guide channels in the wall of the valve body which receive lateral projections on opposite sides of the leaflets. The guide channels take the form oE generally polygonal shaped pockets, and the lateral projections are defined by elongated members which are dimensioned to slide as well as pivot -through -the channels in regulating the opening and closing of -the leaflets. In that approach, the lateral projections are mounted on flat skirts so as to enh~nce the response time of the leaflets.
Others have proposed leaflet type valves which are capable of pivotal or swinging movement about a fixed axis, such as, by pins or notched elements serving as lateral projections which are insertable into sockets in the wall of the body. Representa-tive of this approach are disclosed in U.S. Letters Patent Nos. 3,626,518 and 3,312,327. Fur-ther, U.S. Letters Patent Nos. 4,011,601 and 3,903,548 disclose the use of depressions or guide surfaces which will minimize possible deleterious effects of sockets permitting blood to clot or accumulate in or 3~
arouncl any relatively sharp edges o~ the sockets and pre-vent effecti.ve washing action by the blood. It has also been proposed in the past to form an axially directed extension of the valve body in whi.ch guide surfaces are mounted for the purpose of establishing the pivot point or axis for swinging movement of the leaflets between the open and closed position without substantially increasing the profile or height of the valve. For e~ample, reference is made to U.S. Let-ters Patent No. 4,178,639.
]o In that patent however separate stops are required to regulate the limits of movement of the leaflets, and the leaflets are positioned substantially in the central region of blood flow through the valve when in the open position.
It is therefore an object of the pr~sent inven-tion to provide for a novel and improved artificial heart valve in which one or more valving elemen-ts are movable between an open and closed position in response to the direction of fluid flow therethrough with a minimum of wear and stress imposed upon the elements of the valve.
Another object of the present invention is to provide for a novel and improved prosthetic heart valve in which one or more lea~lets or valve elements are movable through a minimum angle between a fully closed and a fully opened position; and in the open position the leaflet or leaflets will permit substantially unrestricted flow of bloo~ therethrough so as to minimize turbulence and pro-mote laminar flow o~ the blood.
It is another object of -the present invention to provide for a prosthetic hear-t valve in which one or more 1 ~63~4 valve members are so mounted and arranged as to avoid collection of blood at or along the pi.vot points or axes for each valve while el.iminat:ing any sharp projections or stops protruding into the passageway of each valve.
A further object oE the present invention is to provide a prosthetic heart valve oE the leaflet type in which one or ~ore leaflet elements are so constructed and arranged as to increase the ef~ective orifice area or passageway through the valve with a minimal pressure gra-dient thereacross; further to reduce the thickness andsize of the valve body and avoid necessity for a fixed point of rotation at the juncture between each leaflet and valve body which cannot be effectively washed by the flow of blood.
It is an additional object of the present inven-tion to provide for a low profile valve body for aprosthetic heart valve in which guide extensions on the body serve the dual ~unction of guiding and limiting move-ment o a leaflet while avoi.ding localized wear and which further obviate the use of f.ixed pivots or hinges; and, in general, the valve constructions devised will promote long wear, durability, quiet opera-tion with rapid response time while employing a minimum number of parts and greatly simplifying the manufacture oE the valve.
It is a still further object of the present invention to provide in a low proEile valve body for a novel and improved leaflet having guide elements cooperating with recessed guide ex-tensions in the body to establish optimum contact -therebetween as the valve undergoes opening and closing movement; and further 1 11630~4 wherein the leaflet is capable of advancing to a precisely controlled open position without the use of separate stop elements wi-th improved flow along the minor orifice of the valve in the open position and precisely controlled leakage in the closed position.
According to one aspect of the present invention there is provided a prosthetic heart valve comprising: an outer peripheral, generally annular ~ody having an inner wall surface;
at least one leaflet disposed in said body, said leaflet including opposed lateral edge surfaces and leading and trail-ing edge surfaces; and leaflet-supporting means operative to support said leaflet for movement in response to reversals in the direction of fluid flow through said body between an open position in which said leafle-t is substantially parallel to fluid flow through said body and a closed position in which said leaflet extends angularly across said body, said leaflet-supporting means having lateral projections on opposed lateral edge surfaces elongated in a direction parallel to said lateral edge surfaces and guide pocket means for each of said lateral projections, each said guide pocket means disposed in the inner wall surface of said body ~etween said leading edge surface and said trailing edge surface of said leaflet, each said guide pocket means aligned to receive one of said lateral projections whereby to guide pivotal and limited translatory movement of each said leaflet between said open and said closed positions in response to reversals in the direction of fluid flow through said body.
According to another aspect of the invention, there is provided a prosthetic heart valve co~prising: an annular valve body having an inner wall surface interrupted by dia-metrically opposed, straight wall sections, axially directed extensions disposed in diametrically opposed relation to one ~ lB3~4 another and extending in a downstream direction from saidstraight wall sections o;E said hody, each extension including a shallow recess of generally triangular configuration having opposed sidewalls diverging in a downstream direction; and at least one occluder leaflet disposed within said valve body, each leaflet having leading and trailing edge surfaces converg-ing into opposed lateral edge surfaces, each lateral edge surface extendi.ng parallel to and coextensive with one of said straight wall sections and each having a lateral projection inserted into a recess in one of said axial extensions, each said lateral. projection ~eing of a length corresponding to the length of a sidewall of said recess and of a width less than the space between said sidewalls, each pair of lateral pro-jections defining guide means operative to control movement of said leaflet between an open position in which said leaflet is disposed substantially parallel to said valve body and a closed position in which said leaflet is disposed for extension angularly across said valve body.
The above and other objects, ad~antages and features of the present invention will become more readily understood and appreciated from a consideration of the following detailed description of a preferred embodiment of the present invention when taken together with the accompanying drawings in which:
Figure 1 is a plan view of a preferred form of bi-leaflet artificial heart valve as viewed from the downstream side of the valve, in accordance with the present invention;
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Figure 2 is a cross-sectional view taken ahout lines 2-2 of Figure l;
Figure 3 is a cross-sectional view taken about lines 3-3 of Figure 1;
Figure 4 is a view taken about lines ~-4 of Figure 2;
Figure 5 is a side view of a preferred form of leaflet as illustrated in Figures 1 and 2;
Figure ~ is a plan view o the leaflet shown in Figure 5;
Figure 7 is a cross-sectional view taken about lines 7-7 of E'igure 5;
Figure 8 is a plan view of a modified orm of tri-leaflet valve construction with one portion broken away to illustrate the configuration of a channel for guiding movement of the leaflets therein;
Figure 9 is a front view of the valve construc-tion shown in Figure 8;
Figure 10 is a cross-sectional view taken abou-t lines lO-lO of Figure 8;
Figure 11 is a plan view of a modified form of valve body as shown in Figure 9 with a portion broken away to illustrate the configuration o one of the guide channels;
Figure 1.2 is a plan view of one of the occluder leaflets of the modiEied form of invention;
Figure 13 is a front view of the occluder leaflet shown in Figure 12;
Figure 14 is a cross-sectional view taken about lines 14-14 of Figure 13;
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Figure 15 is a plan view of a preferrec1 form oE
single leaflet artificial hear-t valve construction;
F.iyure ].6 is a cross-sectional vlew of the valve assembly shown in Figure 15 and illustrating the mounting of a suture ring thereon, Figure 17 is a cross-sectional view taken about lines 17-17 of Figure 16, Figure 18 is a cross-sectional view of a guide pocket taken about lines 18-18 of Figure 16, Figure 19 is a plan view of the single leaflet illustrated in Fi.gures 15 and 16;
Figure 20 is a side view of the leaflet shown in Figure 19; and Figure 21 is a cross-sectional view taken about lines 21-21 of Figure 20.
In the preferred form of present invention, as illustrated in Figures 1 to 7, a bi.-leaflet valve 10 is comprised of a valve body 1~ of generally annular con-figuration having diametrically op~osed arcua-te wall sec-tions 13 interconnected by straight wall sections 14, andthe valve body is surrounded by an outer concentric suture ring 15. Valve members or occluder leaflets 16 are disposed for pivotal movement within the valve body in a manner to be hereinafter described in more detail.
Both the arcuate wall sections 13 and the strai.ght wall sections 14 are of generally channel-shaped cross-sectional configura-tion, as noted from the cross-sectional views oE Figures~ and ~; so as -to define a generally concave, channel-shaped external wall surface 18 which is adapted to receive the suture ring 15, the suture ~ :~63~54 ring being of conventional construction and provided with an outward]y projecting collar 18 to facilitate implan-tation of the valve into the heart, for instance, as a substitute for -the mitral valve. A modified type of suture ring, not shown, may be employed when the valve is -to be implanted in place of the aortic valve.
An inner wall surface 20 of the valve body 12 is characterized by being flat throughout its greater height except for the downstream and upstream ends 21 and 22 ]0 which flare outwardly to ~orm the external channel-shaped configuration of the external wall 18. In addition, each straight wall section 14 is provided with an axial exten-sion 24, each extension forming a direct continuation of the inner wall surface 20 in a downstream direction and terminating in a somewhat convex downstream edge 25. Each extension 24 is symmetrically ~ormed about the cen-ter of its associated straight wall section and has an external inclined wall surface 26 which converges upwardly from the upper end 21 into the convex edge 25 of the extension.
A pair of guide poc~ets in the form of shallow recesses or channels 28 are formed at opposite ends of each straight wall section 14 and, as illustrated in Figures 2 to 4, each channel is of a height to project from a poin-t adjacent to upstream or lower edge 22 o~ the wall section to the downstream or convex edge 25 of the extension wall 24. As viewed in ~igure 2, each guide A pocket or channel ~ is o~ generally triangular con~
figuration which is truncated by the intersection o~ a relatively short upstream edge 30 with divergent side ~y~?r ~
edges 32 and 33. The-~ff~t-r~a~ edge 30 is of a width _ g _ ~ ~3~
just greater than the width of the guide member to be described for the associated leaflet, and a relatively wide downstream edge 31 is of curved or arcuate configura-tion. In the preferred form, the divergent edge 32 is disposed at an angle on the order of 5 to 9 to the longi-tudinal axis of the valve while the edge 33 which establish-es the closed position of the valve, is disposed at an angle on the order of 45to the longitudinal axis. In other words, the included angle betw~en opposed sidewalls or edges 32 and 33 in each recess is on the order of 36 to 40. The inner wall or bearing surface 34 of each channel is of somewhat curvilinear configuration having an arcuate or somewhat elliptical intermediate wall surface which verges into sloping or gently curving surfaces at the outer surrounding edges 30 and 31, as shown in Figure 3, but is fla~ across its width and terminates in the more sharply angled edges 32 and 33, as shown in Figure 4.
The cccluder leafle-ts 16 are mounted for pivotal movement within the channel 28 between a closed position as illustrated in full in Figures 1 and 2 and an open position as shown dotted in Figure 2. The leaflets 16 are of corresponding size and confi.guration and, as shown in more detail in Figures 5 to 7~ each leaflet has a generally shovel-shaped major wall portion 40 which is of generally elliptical configuration with a concave surface 41 cn one side and convex surface 42 on the opposite or downstream side. The elliptical wall portion terminates on opposite sides in reversed curved sections which flat-ten or straighten into lateral edges or skirts 42, the skirts projecting a limited distance in opposite direc-tions to one another. Each skirt 42 terminates in a straight edge 43, and a slide control member 44 protrudes away rom the straight edge, the slide con-txo]. mernber 44 being somewhat elongated as illustrated in Figure 5 and having an external curved or convex surface 46 corresponding to the curvature of the bearing surface 34 in its associated channel 280 ~ s viewed from Figure 5, each leaflet can be further characterized as being in the essential form of a A triangle having a hypoten~use extending centrally of the major wall portion of the leafle-t and equilateral side edges 47 and 48 which define the leading or upstream edge of the leaflet and the trailing or downstream edge of the leaflet, respectively. The triangle as described is trun-cated by the intersection of the sides 47 and 48 with the skirts 42, the skirts ~2 e~tending between the sides 47 and 48 parallel to the hypoteneuse or midsection o~ the wall portion. ~ach upstream edge 47, as viewed in Figure 6, i9 formed on a radius of curvature corresponding to that of a curved wall section 13 o~ the annular body and intersects the straight edged skirts 42 at a point corresponding to the straight wall sections 14 of the bod~. In turn, the downstream edge 48 of each leaflet is movable into flush engagement with a corresponding edge 48 of the opposite leaflet when the leaElets move into the closed position, as illustrated in Eull in Figure 2, with the upstream edges 47 movable into contact with the arcuate wall sections 13 o~ the body.
Considering the relationship between -the slide control members 44 and their respective channels 28, it will be noted from Figures l and 2 that when the lea:Elets are disposed in theix closed posi-tion, each slide control ~ ~30~
member 4~ will extend substantially at a 45 angle -to the longitudinal axis oE -the body and parallel to the inner side edge 33 oE i.-ts associated c~annel. Each slide control member is of a length corresponding to the length of the longer edges 32 and 33 but is of a width less than the width be-tween the side edges 32 and 33 at their narrowest poin-t along the upstream edge 30. In this way, the slide control member do s not have a fixed point of rotation as it advances through -the channel but is free to underyo a combination of sliding and pivotal movement as it advances from the closed position to the open position adjacent to or abutting the opposite side edge 32 so as to achieve most effective washing action within the guide channels or pockets 28 as the leaflets are controlled by fluid pressure in their movement between the open and closed positions~ Moreover, -the slide control members are curved only in a lengthwise direction and are flat across their width so as to correspond to the flat bearing sur-face of its associated channel and are of a depth to be fully seated within each of the respective channels 28 as illustrated in Figure 3.
When liquid or fluid under pressure is applied to the upstream or concave surfaces 41 oE the leaflets, the opening pressure against the leaflets will cause the slide control members 44 to be advanced from the position shown in full in Figure 2 to the dotted line position as described. A~ain, the slide control members will undergo both a sliding or translational movement together with a swinging or pivotal movement through the channels with the upstream end of the slide con-trol member :Eree to slide ~ ~3~
along ~he upstream edge 30 and the downstream end of -the member being free to advance with respect to the downstream edge 31 of the channel until the member advan-ces from a position abutting the inner side edge 33 to an open position abutting the ou-ter side edge 32. In the open position, the leaflets will have been advanced from a substantially 45 angle to an approximate 5 angle -to the longitudinal axis, or just less than parallel to the longitudinal axis. In this relation, the leaflets will have moved in an outward direction toward the inner wall surfaces of -the body so as -to form an open passageway for the liquid or fluid to flow therethrough and which passa-geway is free of any obstructions other than the limited projection of the skirts 42 along the straight wall sections. By eliminating any fixed axis or point of rota-tion between the slide control members and channels, the blood or other liquid flowing therethrough can effectuate more complete washing action of the channels which could otherwise tend to collect the blood or other liqui~.
Moreover, the blood will be free to pass to a limited extent between the skirt portions 32 and straight wall sections 14 so as to have the effect of a washing action on the mating surfaces between the slide control members 44 and associated channels 28. When the direction of liquid or fluid flow is reversed, the pressure will be : shifted to bear against the convex or downstream surface 4~ of each leaflet so as to cause the slide control mem-bers 44 to undergo reverse movement through the channels in an ups-tream or radially inwa~d direction until the edges 48 of the leaflets re-turn into closed relation to ~ 1~3~
one another so as to effectivel~ check the Elow in the reverse direction. Forma-tion of the slide control members with respect to -the pocke-ts 28 in the manner descrlbed will eliminate any tendency oE the leafle-ts -to move beyond the open position shown in Figure 2 but at the same time obviates the use of separate limit stops or projections to regulate the degree oE opening or closing movement. Still further, the somewhat fan-shaped configuration of -the channels 28 in the e~tension walls along the straight wall sections 14 permits construction of a low pro*ile valve while achieving rapid response time in opening and closing of the valve to reversals in fluid or liquid flow therethrough.
In the modified form of invention, a tri-cuspid or tri-leaflet valve is illustrated and generally designated at 50 which is comprised of an annular body 52 provided with extension walls 53 at equally spaced circum-. Eerential intervals in which are positioned guide pocke-ts or channels 54 to guide and support occluder leaElets or valve members 55. In the tri-leaflet :Eorm, a series of three leaflets are positioned within the body, each being of corresponding size and width having slide control mem-bers 56 on opposite sides of each lea~let which are . movable through -the guide channels 54 between a closed position as illustrated in Figure 8 and an open position as illustrated in Figure 10.
The annular body 52 is once again of generally channel-shaped configuration having a straight inner wall sur~ace 58 bounded by flared ends 5~ and 60 on its downstream and ups-tream sides, respectively. A suture ~ ~ 63~
ring 62 is positioned within the channel Eormed by the flared ends 59 and 60 and is provided w:ith a coll.ar 63 projec~ing in a radial outward direction frorn the body to facil.ita-te implantation as a mitral valve in the manner described in the preferred :Eorm. Although the upstream end 60 of the body is flat, the downstream end 59 is somewhat scalloped or concave, as indicated at 64 in Figure ~, in its extension between -the extension walls 53.
The extension walls 53 in turn project in an axial direc-tion away from the main wall oE the body and are oEsomewhat triangular cross-sec-tion as viewed in Figure 8, so as to present radially inwardly inclining, equilateral side surfaces 65 and 66 which intrude for a limited distance from the inner straight wall surface of the body.
As a result, the extension walls are formed so as to be of gradually increased thickness in extending in a downstream direction away from the body 52 and -terminate in .inclined downstream surfaces 67 ~nd 68 which are joined or inter-connected by a horizontal edge 69.
Each of the channels 54 is formed in the sides 65 and 66 of each extension wall 53 and correspond in construction as well as intended function with the chan-nels 28 of the preferred form of invention. Accordingly, like parts or sur:Eaces of the channels 54 are correspon-dingly enumera-ted to that of the preferred form of Figures 1 to 7.
As shown in Figures 12 to 14, each occluder leaflet or valve member 55 is o-f corresponding size and configuration and is dimensioned ~or insertion between confronting sides 65 and 66 of adjacent extension walls so ~ :L~3~
as to move be-tween a closed position as shown in full in Figure 8 and an open position as shown in do-tted form in Figure 10. Each occluder leaflet can be generally charac-terized as being shovel-shaped and of a somewhat flatter curved configuration than the preferred form oE bi-leaElet arrangement shown in Figures 1 to 7. Each leaflet has leading straight edges 70 which converge to an apex or point 71 and are somew~at beveled or tapered as indicated at 72 so as to move into -flush engagement with adjoining leading edges of the o-ther leaflets in the closed position shown in Figure 8. In addition, each leaflet has a beveled trailing edge 74 which is formed on a radius o~
curvature corresponding to the inner wall surEace 58 of the body with opposite ends of the trailing edge 74 inter-secting straight lateral edges 76 on opposite sides of each leaflet. A slide control member 56 pro-trudes ~rom the lateral edge 76 on each side of the leaflet and is of gerlerall~ lobe-shaped configuration corresponding to the con~iguration of the slide control members 44 of the pre-ferred form. The lateral edges 76 are of a length so asto be free to slide or advance along- the correspondingly flat surfaces of the sides 65 or 66 of the extension walls with the slide control member 56 movable through a guide channel 54 in controlling opening and closing movement of the leaflets.
It will be noted in the tri-leaflet configuration, that the leading edges of the leafle-ts 55 deLlne a ~enerally Y-shaped parting line in the closed position, and similarly, each pair of adjoining leaflets define a Y-shaped parting line wi-th a colnmon e~tension wall, as seen frorn a consideration of Figure ~.
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The modified form of valve is characterized by being of a somewhat lower profile ~tlan ~ile L~re~e~rred form and in certain applications, such as, :Eor implanta-tion in place of the aortic valve will better conform to the con-figuratiorl of the comissures of the natural valves.
Moreover, the part:icular configuration of the valve body enables the leaflets to be posit.ioned somewhat fur-ther down into the valve body so as to be of a lower profile than the bi-leaElet valve.
A preferred form of single lea-Elet valve 80 includes an annular ~alve ~ocly 81 havirly diametrically opposed, arcuate wall sections 82 interconnected by straight wall sections 84, and a suture ring 15 corresponding to -t~la-t illustrated in Figure 1, is mounted in outer surrounding relation to the valve body. A single occluder leaflet 86 is disposed for pivotal movernent within the valve body between a closed position, as illustrated in full in Figure 16, extending a-t an acute angle to a plane through the valve body and an open posi-tion extending at an acute angle to the longitudinal axis of the valve body, as illustrated in dotted form in Figure 16.
Referring in more detail to the construction of the valve body 81, both the arcuate wall sections 82 and straight wall sec-tions 84 again define a general channel-shaped member having an external concave or channel-shaped external wall surface 88 adapted to receive the suture ring 15, and the ring includes an outwardly projecting collar 89 to facilitate implantation of the valve into the heart, for instance, as a substi-tute for the mitral valve.
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Of course, the suture ring may be modified as nscessary according to the particular locus oE -the implan-ta-tion into the heart. An inner wall surface 90 of -the body 81 is characterized by being relatively flat throughout its grea-ter haight, save for the downstream and upstream ends 9l and 92 which flare outwardly to form the ex-ternal wall 88, and an arcua-te ledge 93 is formed in the inner wall to ex-tend circumferentially around one of the arcua-te wall sections 82, the ledge facing in the downstream direction and adapted to serve as a supporting surface for the leaflet 86 in a manner to be described. In this respect, as shown in Figure 16, the ledge 93 slopes upwardly from its midpoint, or in other words is given a slight con-cavity so as to 'De complemen-tary to -the convex ups-tream surface of the leaflet as hereinafter described.
Moreover, each straight wall section 84 has an axial extension 94 which forms a direct axial continuation of the valve body in a downstream direction and terminates in a generally convex or triangular edge 95. Each extension 94 is correspondingly disposed in offset relation to the center line of the valve body so as to ex-tend upwardly from a point relatively near one encl of each straight wall section and with -the extensions being aligned in opposed confr~nting relation to one another.
Guide pockets are defined by shallow recesses or bearing surfaces 98, each pocke-t being oE a height to pro-ject Erom a point adjacent -to a downstream edge of a wall section 84 to the downstream edge or apex of -the axial extension. Each guide pocket 98 is of generally triangu-lar conEiguration having an upstream end lO0 and a curved - lS -~ ~3~
downstream edge 101 interconnected by divergent side edges 102 and 103. The upstream end 100 is at the intersec-tion of the side edges 102 and 103 or may be truncated somewhat as described with reference to the forms illustrated in Figures 1 to 14. In this form, the outer divergent side edge 102 is disposed at an angle on the order of 25 to the longitudinal axis of the valve while the opposite or inner edge 103 is disposed at an angle on the order of 80-85 to the longitudinal axis. The inner bearing sur-face 98 of each guide pocket is of generally curvilinear configuration having a generally concave intermediate wall surface which is in the form of a gently curving ellipse in cross-section in a direction between the upstream and downstream edges 100 and 101, but is flat in cross-section at any ~oint in its extension across the width between the divergent edges 102 and 103.
The single leaflet 86 is mounted for pivotal movement within the valve body between a closed position as illustrated in full in Figure 16 and an open position, as shown dotted in Figure 16. As shown in Figures 19 to 21, the leaflet has a generally shovel-shaped major wall portion 110 which is of concavo-convex configuration and provided with a concave surface 111 on its downstream side and a convex surface 112 on i-ts opposite or upstream side.
The leaflet terminates on opposite sides in flat side .: extensions projecting a limited distance in opposite directions to one another so as to terminate in straight edges 113. A guide or slide control member 114 protrudes from each of the straight edges 113 and is somewhat elongated as illustrated in Figure 15 with a gently curved or convex edge 116 terminating in a squared or straight : - 19 -3~5~
c~ge 116'' and a rounded edge 116' at its juncture with the straight edge 113. The yuide member 114 is dimen-sioned such that when inserted into a respective guide pocket, the edges 116' and 116'' will bear slightly against the opposed upstream and downstream edges 100 and 101 with the generally convex edge 116 seated on the bearing surface 98 in the guide pocket. Most desirably, the convex edge 116 is given an elliptical curvature along its length from the leading edge portion 116' rearwardly which corresponds to the elliptical curvature of the bearing surface 98;
however, the trailing edge 116'' of the straight edge 113 is transversely rounded symmetrically about the center line of the slide member 114 to permit it to pivot smoothly bet-ween the open and closed positions and will enable the slide members 114 to move freely into flush engagement with the divergent sides 103 and 104 without interference bet-ween the elliptical bearing surface 98 and the convex edge 116. As a result, the guide pockets 98 will establish a precisely controlled angle of the leaflets in the open position and avoid any shifting or misalignment between the trailing edge 116'' and upstream edge 100 at the narrow end of the guide pocket.
In the construction of the single leaflet~ the lateral edges 113 are dimensioned to correspond substan-tially to or be slightly less than the length of the straight wall sections 84, and arcuate leading and trailing edge surfaces 117 and 118 correspond substan-tially to the arcuate wall sections 82 of the valve body, except for allowance of a slight gap between the leading ~ ~3~
edge 118 and the arcuate wall sec-tion 82, as shown in Figures 15 and 16. Here, the single leaElet construction can be broadly characterized as being of a gentler slope or curvature than that of the bi-leaflet or tri-leaflet constructions hereinbefore described and is formed on a curvature between the lateral edges on the order of a 6.5 ellipse. Thus, when the guide members 114 are inserted into their respective guide pockets, the leaflet i5 controlled in its movement between a closed position in 10 which the leading edge 117 engages the arcuate ledge 93 and an open position, again as shown dotted in Figure 16, in which the leaflet is disposed more nearly parallel to the longitudinal axis of the valve body. By virtue of the slight angle or inclination of the leaflet 86 in the closed position, the leaflet 93 s:Lopes at a corresponding an~le radially inwardly and in an upstream direction so that the leading edge 117 will advance into substantially flush relation to the ledge 93. l1owever, owing to the gap formed between the leaflet and arcuate wall sec~ion 82 adjacent to the ledge 93 a controlled leakage of blood past the leaflet is permitted in the closed position just sufficient to keep the blood agitated and avoid any ten-dency to clot or coagulate.
When blood flows under pressure into the heart and is applied to the upstream or convex surface 112 of the leafletl the opening pressure against the leaflet will cause its slide control members 114 to undergo a com-bination of sliding and pivotal movement from the position shown in full in Figure 16 to the dotted line position~
In undergoing both a l:imited sliding or translational ~ 1~3~
~ovement along with a pivotal movement through the guide pockets, the slide control members 11~ will advance from a position abutting the divergent edge 103 to an open posi~
tion abutting the edge L02. In moving to the open position, the leaflet will have undergone a movement of substantially 60 toward the arcuate wall section oE the valve body so as to form open passageways for the blood to flow both along the major and minor orifices and which passageways are free of any obstructions along opposed surfaces of the leaflets. Once again, by eliminating a fixed axis or point of rotation between the guide members and guide pockets, the blood or other liquid flowing therethrough can effec-tuate more complete washing action of the guide pockets while being free to pass to some extent between the side extensions and straight wall sections, thereby having the effect of a washing action on the mating surfaces between the slide control members 114 and guide pockets 98. When the direction of flow of blood is reversed, the fluid pressure will be applied to the concave surface 111 of each leaflet so as to cause the guide members 114 to undergo reverse movement through the guide pockets in an upstream direction until the leading edge of the leaflet returns into closed relation to the supporting ledge 93 and effec-tively checks the flow of blood in a reverse direction.
It is therefore to be understood that while pre-ferred and modified form of the invention have been set forth and disc:Losed herein that various modifications and changes may be made without departing from the spiri-t and scope of -the invention as defined by the appended claims.
This invention relates to valves and more par-ticularly relates to artificial heart valves which can be transplanted into the mitral, aortic, tricuspid or pulmo-nic portions of the heart.
Numerous types of prosthetic heart valves have been devised to the end of replacing defective natural heart valves and to simulate as closely as possible the operation Gf natural heart valves. Essentially, the natural valves in the human heart operate as check valves which are capable of operating between open and closed positions in response to the flow of blood to and from the heart. As disclosed in prior copending application for patent, Serial ~o. 84,318, filed 12 October, 19~9, now U.S.
Letters Patent No. 4,363,142, granted 14 October, 1982, and assigned to the assignee of this application, it is essen-tial that the artificial heart valve be capable of achieving the ra~pid response time of the natural heart valve to the reverse flow of blood in moving between the open and closed positions. Moreover, the valve should be capable of achieving a maximum opening to an angle in excess of 60~ to the transverse axis of the valve for the passage of blood with a minimum of turbulence. Further, the valve must have a low profile or height so as to pre-vent any possible interference with the ventricular septum as well as to minimize aortic obstruction and low cardiac output. In this same relation, it is equally important that there be a low pressure gradient between the upstream and downstream ends of the valve when the valve is in its open position. For instance, a pressure gradient on -the order of 20 millimeters to 50 millimeters of mercury in a natural heart valve is symptomatic of defective func-tioning of the valve; whereas, the pressure gradient or ~3 -- 1 -- !
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drop of a properly func-tioning valve should be less -than 10 millimeters of mercury~
Previously, U.S. Letters Patent ~o. 3,589,392 emplo~ed curved leaflets which were hinged to a valve body for pivotal movement between the open and closed positions. ~ore recently, the hereinbefore referred to copending application for patent was directed to a novel and improved form of guide assembly which is especially adapted for curved leaflets 50 as to directionally control the mov~ment of the leaflets in response to the direction of liquid or blood flow therethrough, -the guide assembly including guide channels in the wall of the valve body which receive lateral projections on opposite sides of the leaflets. The guide channels take the form oE generally polygonal shaped pockets, and the lateral projections are defined by elongated members which are dimensioned to slide as well as pivot -through -the channels in regulating the opening and closing of -the leaflets. In that approach, the lateral projections are mounted on flat skirts so as to enh~nce the response time of the leaflets.
Others have proposed leaflet type valves which are capable of pivotal or swinging movement about a fixed axis, such as, by pins or notched elements serving as lateral projections which are insertable into sockets in the wall of the body. Representa-tive of this approach are disclosed in U.S. Letters Patent Nos. 3,626,518 and 3,312,327. Fur-ther, U.S. Letters Patent Nos. 4,011,601 and 3,903,548 disclose the use of depressions or guide surfaces which will minimize possible deleterious effects of sockets permitting blood to clot or accumulate in or 3~
arouncl any relatively sharp edges o~ the sockets and pre-vent effecti.ve washing action by the blood. It has also been proposed in the past to form an axially directed extension of the valve body in whi.ch guide surfaces are mounted for the purpose of establishing the pivot point or axis for swinging movement of the leaflets between the open and closed position without substantially increasing the profile or height of the valve. For e~ample, reference is made to U.S. Let-ters Patent No. 4,178,639.
]o In that patent however separate stops are required to regulate the limits of movement of the leaflets, and the leaflets are positioned substantially in the central region of blood flow through the valve when in the open position.
It is therefore an object of the pr~sent inven-tion to provide for a novel and improved artificial heart valve in which one or more valving elemen-ts are movable between an open and closed position in response to the direction of fluid flow therethrough with a minimum of wear and stress imposed upon the elements of the valve.
Another object of the present invention is to provide for a novel and improved prosthetic heart valve in which one or more lea~lets or valve elements are movable through a minimum angle between a fully closed and a fully opened position; and in the open position the leaflet or leaflets will permit substantially unrestricted flow of bloo~ therethrough so as to minimize turbulence and pro-mote laminar flow o~ the blood.
It is another object of -the present invention to provide for a prosthetic hear-t valve in which one or more 1 ~63~4 valve members are so mounted and arranged as to avoid collection of blood at or along the pi.vot points or axes for each valve while el.iminat:ing any sharp projections or stops protruding into the passageway of each valve.
A further object oE the present invention is to provide a prosthetic heart valve oE the leaflet type in which one or ~ore leaflet elements are so constructed and arranged as to increase the ef~ective orifice area or passageway through the valve with a minimal pressure gra-dient thereacross; further to reduce the thickness andsize of the valve body and avoid necessity for a fixed point of rotation at the juncture between each leaflet and valve body which cannot be effectively washed by the flow of blood.
It is an additional object of the present inven-tion to provide for a low profile valve body for aprosthetic heart valve in which guide extensions on the body serve the dual ~unction of guiding and limiting move-ment o a leaflet while avoi.ding localized wear and which further obviate the use of f.ixed pivots or hinges; and, in general, the valve constructions devised will promote long wear, durability, quiet opera-tion with rapid response time while employing a minimum number of parts and greatly simplifying the manufacture oE the valve.
It is a still further object of the present invention to provide in a low proEile valve body for a novel and improved leaflet having guide elements cooperating with recessed guide ex-tensions in the body to establish optimum contact -therebetween as the valve undergoes opening and closing movement; and further 1 11630~4 wherein the leaflet is capable of advancing to a precisely controlled open position without the use of separate stop elements wi-th improved flow along the minor orifice of the valve in the open position and precisely controlled leakage in the closed position.
According to one aspect of the present invention there is provided a prosthetic heart valve comprising: an outer peripheral, generally annular ~ody having an inner wall surface;
at least one leaflet disposed in said body, said leaflet including opposed lateral edge surfaces and leading and trail-ing edge surfaces; and leaflet-supporting means operative to support said leaflet for movement in response to reversals in the direction of fluid flow through said body between an open position in which said leafle-t is substantially parallel to fluid flow through said body and a closed position in which said leaflet extends angularly across said body, said leaflet-supporting means having lateral projections on opposed lateral edge surfaces elongated in a direction parallel to said lateral edge surfaces and guide pocket means for each of said lateral projections, each said guide pocket means disposed in the inner wall surface of said body ~etween said leading edge surface and said trailing edge surface of said leaflet, each said guide pocket means aligned to receive one of said lateral projections whereby to guide pivotal and limited translatory movement of each said leaflet between said open and said closed positions in response to reversals in the direction of fluid flow through said body.
According to another aspect of the invention, there is provided a prosthetic heart valve co~prising: an annular valve body having an inner wall surface interrupted by dia-metrically opposed, straight wall sections, axially directed extensions disposed in diametrically opposed relation to one ~ lB3~4 another and extending in a downstream direction from saidstraight wall sections o;E said hody, each extension including a shallow recess of generally triangular configuration having opposed sidewalls diverging in a downstream direction; and at least one occluder leaflet disposed within said valve body, each leaflet having leading and trailing edge surfaces converg-ing into opposed lateral edge surfaces, each lateral edge surface extendi.ng parallel to and coextensive with one of said straight wall sections and each having a lateral projection inserted into a recess in one of said axial extensions, each said lateral. projection ~eing of a length corresponding to the length of a sidewall of said recess and of a width less than the space between said sidewalls, each pair of lateral pro-jections defining guide means operative to control movement of said leaflet between an open position in which said leaflet is disposed substantially parallel to said valve body and a closed position in which said leaflet is disposed for extension angularly across said valve body.
The above and other objects, ad~antages and features of the present invention will become more readily understood and appreciated from a consideration of the following detailed description of a preferred embodiment of the present invention when taken together with the accompanying drawings in which:
Figure 1 is a plan view of a preferred form of bi-leaflet artificial heart valve as viewed from the downstream side of the valve, in accordance with the present invention;
..~,., ~ :163~
Figure 2 is a cross-sectional view taken ahout lines 2-2 of Figure l;
Figure 3 is a cross-sectional view taken about lines 3-3 of Figure 1;
Figure 4 is a view taken about lines ~-4 of Figure 2;
Figure 5 is a side view of a preferred form of leaflet as illustrated in Figures 1 and 2;
Figure ~ is a plan view o the leaflet shown in Figure 5;
Figure 7 is a cross-sectional view taken about lines 7-7 of E'igure 5;
Figure 8 is a plan view of a modified orm of tri-leaflet valve construction with one portion broken away to illustrate the configuration of a channel for guiding movement of the leaflets therein;
Figure 9 is a front view of the valve construc-tion shown in Figure 8;
Figure 10 is a cross-sectional view taken abou-t lines lO-lO of Figure 8;
Figure 11 is a plan view of a modified form of valve body as shown in Figure 9 with a portion broken away to illustrate the configuration o one of the guide channels;
Figure 1.2 is a plan view of one of the occluder leaflets of the modiEied form of invention;
Figure 13 is a front view of the occluder leaflet shown in Figure 12;
Figure 14 is a cross-sectional view taken about lines 14-14 of Figure 13;
~ 1~30~
Figure 15 is a plan view of a preferrec1 form oE
single leaflet artificial hear-t valve construction;
F.iyure ].6 is a cross-sectional vlew of the valve assembly shown in Figure 15 and illustrating the mounting of a suture ring thereon, Figure 17 is a cross-sectional view taken about lines 17-17 of Figure 16, Figure 18 is a cross-sectional view of a guide pocket taken about lines 18-18 of Figure 16, Figure 19 is a plan view of the single leaflet illustrated in Fi.gures 15 and 16;
Figure 20 is a side view of the leaflet shown in Figure 19; and Figure 21 is a cross-sectional view taken about lines 21-21 of Figure 20.
In the preferred form of present invention, as illustrated in Figures 1 to 7, a bi.-leaflet valve 10 is comprised of a valve body 1~ of generally annular con-figuration having diametrically op~osed arcua-te wall sec-tions 13 interconnected by straight wall sections 14, andthe valve body is surrounded by an outer concentric suture ring 15. Valve members or occluder leaflets 16 are disposed for pivotal movement within the valve body in a manner to be hereinafter described in more detail.
Both the arcuate wall sections 13 and the strai.ght wall sections 14 are of generally channel-shaped cross-sectional configura-tion, as noted from the cross-sectional views oE Figures~ and ~; so as -to define a generally concave, channel-shaped external wall surface 18 which is adapted to receive the suture ring 15, the suture ~ :~63~54 ring being of conventional construction and provided with an outward]y projecting collar 18 to facilitate implan-tation of the valve into the heart, for instance, as a substitute for -the mitral valve. A modified type of suture ring, not shown, may be employed when the valve is -to be implanted in place of the aortic valve.
An inner wall surface 20 of the valve body 12 is characterized by being flat throughout its greater height except for the downstream and upstream ends 21 and 22 ]0 which flare outwardly to ~orm the external channel-shaped configuration of the external wall 18. In addition, each straight wall section 14 is provided with an axial exten-sion 24, each extension forming a direct continuation of the inner wall surface 20 in a downstream direction and terminating in a somewhat convex downstream edge 25. Each extension 24 is symmetrically ~ormed about the cen-ter of its associated straight wall section and has an external inclined wall surface 26 which converges upwardly from the upper end 21 into the convex edge 25 of the extension.
A pair of guide poc~ets in the form of shallow recesses or channels 28 are formed at opposite ends of each straight wall section 14 and, as illustrated in Figures 2 to 4, each channel is of a height to project from a poin-t adjacent to upstream or lower edge 22 o~ the wall section to the downstream or convex edge 25 of the extension wall 24. As viewed in ~igure 2, each guide A pocket or channel ~ is o~ generally triangular con~
figuration which is truncated by the intersection o~ a relatively short upstream edge 30 with divergent side ~y~?r ~
edges 32 and 33. The-~ff~t-r~a~ edge 30 is of a width _ g _ ~ ~3~
just greater than the width of the guide member to be described for the associated leaflet, and a relatively wide downstream edge 31 is of curved or arcuate configura-tion. In the preferred form, the divergent edge 32 is disposed at an angle on the order of 5 to 9 to the longi-tudinal axis of the valve while the edge 33 which establish-es the closed position of the valve, is disposed at an angle on the order of 45to the longitudinal axis. In other words, the included angle betw~en opposed sidewalls or edges 32 and 33 in each recess is on the order of 36 to 40. The inner wall or bearing surface 34 of each channel is of somewhat curvilinear configuration having an arcuate or somewhat elliptical intermediate wall surface which verges into sloping or gently curving surfaces at the outer surrounding edges 30 and 31, as shown in Figure 3, but is fla~ across its width and terminates in the more sharply angled edges 32 and 33, as shown in Figure 4.
The cccluder leafle-ts 16 are mounted for pivotal movement within the channel 28 between a closed position as illustrated in full in Figures 1 and 2 and an open position as shown dotted in Figure 2. The leaflets 16 are of corresponding size and confi.guration and, as shown in more detail in Figures 5 to 7~ each leaflet has a generally shovel-shaped major wall portion 40 which is of generally elliptical configuration with a concave surface 41 cn one side and convex surface 42 on the opposite or downstream side. The elliptical wall portion terminates on opposite sides in reversed curved sections which flat-ten or straighten into lateral edges or skirts 42, the skirts projecting a limited distance in opposite direc-tions to one another. Each skirt 42 terminates in a straight edge 43, and a slide control member 44 protrudes away rom the straight edge, the slide con-txo]. mernber 44 being somewhat elongated as illustrated in Figure 5 and having an external curved or convex surface 46 corresponding to the curvature of the bearing surface 34 in its associated channel 280 ~ s viewed from Figure 5, each leaflet can be further characterized as being in the essential form of a A triangle having a hypoten~use extending centrally of the major wall portion of the leafle-t and equilateral side edges 47 and 48 which define the leading or upstream edge of the leaflet and the trailing or downstream edge of the leaflet, respectively. The triangle as described is trun-cated by the intersection of the sides 47 and 48 with the skirts 42, the skirts ~2 e~tending between the sides 47 and 48 parallel to the hypoteneuse or midsection o~ the wall portion. ~ach upstream edge 47, as viewed in Figure 6, i9 formed on a radius of curvature corresponding to that of a curved wall section 13 o~ the annular body and intersects the straight edged skirts 42 at a point corresponding to the straight wall sections 14 of the bod~. In turn, the downstream edge 48 of each leaflet is movable into flush engagement with a corresponding edge 48 of the opposite leaflet when the leaElets move into the closed position, as illustrated in Eull in Figure 2, with the upstream edges 47 movable into contact with the arcuate wall sections 13 o~ the body.
Considering the relationship between -the slide control members 44 and their respective channels 28, it will be noted from Figures l and 2 that when the lea:Elets are disposed in theix closed posi-tion, each slide control ~ ~30~
member 4~ will extend substantially at a 45 angle -to the longitudinal axis oE -the body and parallel to the inner side edge 33 oE i.-ts associated c~annel. Each slide control member is of a length corresponding to the length of the longer edges 32 and 33 but is of a width less than the width be-tween the side edges 32 and 33 at their narrowest poin-t along the upstream edge 30. In this way, the slide control member do s not have a fixed point of rotation as it advances through -the channel but is free to underyo a combination of sliding and pivotal movement as it advances from the closed position to the open position adjacent to or abutting the opposite side edge 32 so as to achieve most effective washing action within the guide channels or pockets 28 as the leaflets are controlled by fluid pressure in their movement between the open and closed positions~ Moreover, -the slide control members are curved only in a lengthwise direction and are flat across their width so as to correspond to the flat bearing sur-face of its associated channel and are of a depth to be fully seated within each of the respective channels 28 as illustrated in Figure 3.
When liquid or fluid under pressure is applied to the upstream or concave surfaces 41 oE the leaflets, the opening pressure against the leaflets will cause the slide control members 44 to be advanced from the position shown in full in Figure 2 to the dotted line position as described. A~ain, the slide control members will undergo both a sliding or translational movement together with a swinging or pivotal movement through the channels with the upstream end of the slide con-trol member :Eree to slide ~ ~3~
along ~he upstream edge 30 and the downstream end of -the member being free to advance with respect to the downstream edge 31 of the channel until the member advan-ces from a position abutting the inner side edge 33 to an open position abutting the ou-ter side edge 32. In the open position, the leaflets will have been advanced from a substantially 45 angle to an approximate 5 angle -to the longitudinal axis, or just less than parallel to the longitudinal axis. In this relation, the leaflets will have moved in an outward direction toward the inner wall surfaces of -the body so as -to form an open passageway for the liquid or fluid to flow therethrough and which passa-geway is free of any obstructions other than the limited projection of the skirts 42 along the straight wall sections. By eliminating any fixed axis or point of rota-tion between the slide control members and channels, the blood or other liquid flowing therethrough can effectuate more complete washing action of the channels which could otherwise tend to collect the blood or other liqui~.
Moreover, the blood will be free to pass to a limited extent between the skirt portions 32 and straight wall sections 14 so as to have the effect of a washing action on the mating surfaces between the slide control members 44 and associated channels 28. When the direction of liquid or fluid flow is reversed, the pressure will be : shifted to bear against the convex or downstream surface 4~ of each leaflet so as to cause the slide control mem-bers 44 to undergo reverse movement through the channels in an ups-tream or radially inwa~d direction until the edges 48 of the leaflets re-turn into closed relation to ~ 1~3~
one another so as to effectivel~ check the Elow in the reverse direction. Forma-tion of the slide control members with respect to -the pocke-ts 28 in the manner descrlbed will eliminate any tendency oE the leafle-ts -to move beyond the open position shown in Figure 2 but at the same time obviates the use of separate limit stops or projections to regulate the degree oE opening or closing movement. Still further, the somewhat fan-shaped configuration of -the channels 28 in the e~tension walls along the straight wall sections 14 permits construction of a low pro*ile valve while achieving rapid response time in opening and closing of the valve to reversals in fluid or liquid flow therethrough.
In the modified form of invention, a tri-cuspid or tri-leaflet valve is illustrated and generally designated at 50 which is comprised of an annular body 52 provided with extension walls 53 at equally spaced circum-. Eerential intervals in which are positioned guide pocke-ts or channels 54 to guide and support occluder leaElets or valve members 55. In the tri-leaflet :Eorm, a series of three leaflets are positioned within the body, each being of corresponding size and width having slide control mem-bers 56 on opposite sides of each lea~let which are . movable through -the guide channels 54 between a closed position as illustrated in Figure 8 and an open position as illustrated in Figure 10.
The annular body 52 is once again of generally channel-shaped configuration having a straight inner wall sur~ace 58 bounded by flared ends 5~ and 60 on its downstream and ups-tream sides, respectively. A suture ~ ~ 63~
ring 62 is positioned within the channel Eormed by the flared ends 59 and 60 and is provided w:ith a coll.ar 63 projec~ing in a radial outward direction frorn the body to facil.ita-te implantation as a mitral valve in the manner described in the preferred :Eorm. Although the upstream end 60 of the body is flat, the downstream end 59 is somewhat scalloped or concave, as indicated at 64 in Figure ~, in its extension between -the extension walls 53.
The extension walls 53 in turn project in an axial direc-tion away from the main wall oE the body and are oEsomewhat triangular cross-sec-tion as viewed in Figure 8, so as to present radially inwardly inclining, equilateral side surfaces 65 and 66 which intrude for a limited distance from the inner straight wall surface of the body.
As a result, the extension walls are formed so as to be of gradually increased thickness in extending in a downstream direction away from the body 52 and -terminate in .inclined downstream surfaces 67 ~nd 68 which are joined or inter-connected by a horizontal edge 69.
Each of the channels 54 is formed in the sides 65 and 66 of each extension wall 53 and correspond in construction as well as intended function with the chan-nels 28 of the preferred form of invention. Accordingly, like parts or sur:Eaces of the channels 54 are correspon-dingly enumera-ted to that of the preferred form of Figures 1 to 7.
As shown in Figures 12 to 14, each occluder leaflet or valve member 55 is o-f corresponding size and configuration and is dimensioned ~or insertion between confronting sides 65 and 66 of adjacent extension walls so ~ :L~3~
as to move be-tween a closed position as shown in full in Figure 8 and an open position as shown in do-tted form in Figure 10. Each occluder leaflet can be generally charac-terized as being shovel-shaped and of a somewhat flatter curved configuration than the preferred form oE bi-leaElet arrangement shown in Figures 1 to 7. Each leaflet has leading straight edges 70 which converge to an apex or point 71 and are somew~at beveled or tapered as indicated at 72 so as to move into -flush engagement with adjoining leading edges of the o-ther leaflets in the closed position shown in Figure 8. In addition, each leaflet has a beveled trailing edge 74 which is formed on a radius o~
curvature corresponding to the inner wall surEace 58 of the body with opposite ends of the trailing edge 74 inter-secting straight lateral edges 76 on opposite sides of each leaflet. A slide control member 56 pro-trudes ~rom the lateral edge 76 on each side of the leaflet and is of gerlerall~ lobe-shaped configuration corresponding to the con~iguration of the slide control members 44 of the pre-ferred form. The lateral edges 76 are of a length so asto be free to slide or advance along- the correspondingly flat surfaces of the sides 65 or 66 of the extension walls with the slide control member 56 movable through a guide channel 54 in controlling opening and closing movement of the leaflets.
It will be noted in the tri-leaflet configuration, that the leading edges of the leafle-ts 55 deLlne a ~enerally Y-shaped parting line in the closed position, and similarly, each pair of adjoining leaflets define a Y-shaped parting line wi-th a colnmon e~tension wall, as seen frorn a consideration of Figure ~.
o~
The modified form of valve is characterized by being of a somewhat lower profile ~tlan ~ile L~re~e~rred form and in certain applications, such as, :Eor implanta-tion in place of the aortic valve will better conform to the con-figuratiorl of the comissures of the natural valves.
Moreover, the part:icular configuration of the valve body enables the leaflets to be posit.ioned somewhat fur-ther down into the valve body so as to be of a lower profile than the bi-leaElet valve.
A preferred form of single lea-Elet valve 80 includes an annular ~alve ~ocly 81 havirly diametrically opposed, arcuate wall sections 82 interconnected by straight wall sections 84, and a suture ring 15 corresponding to -t~la-t illustrated in Figure 1, is mounted in outer surrounding relation to the valve body. A single occluder leaflet 86 is disposed for pivotal movernent within the valve body between a closed position, as illustrated in full in Figure 16, extending a-t an acute angle to a plane through the valve body and an open posi-tion extending at an acute angle to the longitudinal axis of the valve body, as illustrated in dotted form in Figure 16.
Referring in more detail to the construction of the valve body 81, both the arcuate wall sections 82 and straight wall sec-tions 84 again define a general channel-shaped member having an external concave or channel-shaped external wall surface 88 adapted to receive the suture ring 15, and the ring includes an outwardly projecting collar 89 to facilitate implantation of the valve into the heart, for instance, as a substi-tute for the mitral valve.
~ ~3~
Of course, the suture ring may be modified as nscessary according to the particular locus oE -the implan-ta-tion into the heart. An inner wall surface 90 of -the body 81 is characterized by being relatively flat throughout its grea-ter haight, save for the downstream and upstream ends 9l and 92 which flare outwardly to form the ex-ternal wall 88, and an arcua-te ledge 93 is formed in the inner wall to ex-tend circumferentially around one of the arcua-te wall sections 82, the ledge facing in the downstream direction and adapted to serve as a supporting surface for the leaflet 86 in a manner to be described. In this respect, as shown in Figure 16, the ledge 93 slopes upwardly from its midpoint, or in other words is given a slight con-cavity so as to 'De complemen-tary to -the convex ups-tream surface of the leaflet as hereinafter described.
Moreover, each straight wall section 84 has an axial extension 94 which forms a direct axial continuation of the valve body in a downstream direction and terminates in a generally convex or triangular edge 95. Each extension 94 is correspondingly disposed in offset relation to the center line of the valve body so as to ex-tend upwardly from a point relatively near one encl of each straight wall section and with -the extensions being aligned in opposed confr~nting relation to one another.
Guide pockets are defined by shallow recesses or bearing surfaces 98, each pocke-t being oE a height to pro-ject Erom a point adjacent -to a downstream edge of a wall section 84 to the downstream edge or apex of -the axial extension. Each guide pocket 98 is of generally triangu-lar conEiguration having an upstream end lO0 and a curved - lS -~ ~3~
downstream edge 101 interconnected by divergent side edges 102 and 103. The upstream end 100 is at the intersec-tion of the side edges 102 and 103 or may be truncated somewhat as described with reference to the forms illustrated in Figures 1 to 14. In this form, the outer divergent side edge 102 is disposed at an angle on the order of 25 to the longitudinal axis of the valve while the opposite or inner edge 103 is disposed at an angle on the order of 80-85 to the longitudinal axis. The inner bearing sur-face 98 of each guide pocket is of generally curvilinear configuration having a generally concave intermediate wall surface which is in the form of a gently curving ellipse in cross-section in a direction between the upstream and downstream edges 100 and 101, but is flat in cross-section at any ~oint in its extension across the width between the divergent edges 102 and 103.
The single leaflet 86 is mounted for pivotal movement within the valve body between a closed position as illustrated in full in Figure 16 and an open position, as shown dotted in Figure 16. As shown in Figures 19 to 21, the leaflet has a generally shovel-shaped major wall portion 110 which is of concavo-convex configuration and provided with a concave surface 111 on its downstream side and a convex surface 112 on i-ts opposite or upstream side.
The leaflet terminates on opposite sides in flat side .: extensions projecting a limited distance in opposite directions to one another so as to terminate in straight edges 113. A guide or slide control member 114 protrudes from each of the straight edges 113 and is somewhat elongated as illustrated in Figure 15 with a gently curved or convex edge 116 terminating in a squared or straight : - 19 -3~5~
c~ge 116'' and a rounded edge 116' at its juncture with the straight edge 113. The yuide member 114 is dimen-sioned such that when inserted into a respective guide pocket, the edges 116' and 116'' will bear slightly against the opposed upstream and downstream edges 100 and 101 with the generally convex edge 116 seated on the bearing surface 98 in the guide pocket. Most desirably, the convex edge 116 is given an elliptical curvature along its length from the leading edge portion 116' rearwardly which corresponds to the elliptical curvature of the bearing surface 98;
however, the trailing edge 116'' of the straight edge 113 is transversely rounded symmetrically about the center line of the slide member 114 to permit it to pivot smoothly bet-ween the open and closed positions and will enable the slide members 114 to move freely into flush engagement with the divergent sides 103 and 104 without interference bet-ween the elliptical bearing surface 98 and the convex edge 116. As a result, the guide pockets 98 will establish a precisely controlled angle of the leaflets in the open position and avoid any shifting or misalignment between the trailing edge 116'' and upstream edge 100 at the narrow end of the guide pocket.
In the construction of the single leaflet~ the lateral edges 113 are dimensioned to correspond substan-tially to or be slightly less than the length of the straight wall sections 84, and arcuate leading and trailing edge surfaces 117 and 118 correspond substan-tially to the arcuate wall sections 82 of the valve body, except for allowance of a slight gap between the leading ~ ~3~
edge 118 and the arcuate wall sec-tion 82, as shown in Figures 15 and 16. Here, the single leaElet construction can be broadly characterized as being of a gentler slope or curvature than that of the bi-leaflet or tri-leaflet constructions hereinbefore described and is formed on a curvature between the lateral edges on the order of a 6.5 ellipse. Thus, when the guide members 114 are inserted into their respective guide pockets, the leaflet i5 controlled in its movement between a closed position in 10 which the leading edge 117 engages the arcuate ledge 93 and an open position, again as shown dotted in Figure 16, in which the leaflet is disposed more nearly parallel to the longitudinal axis of the valve body. By virtue of the slight angle or inclination of the leaflet 86 in the closed position, the leaflet 93 s:Lopes at a corresponding an~le radially inwardly and in an upstream direction so that the leading edge 117 will advance into substantially flush relation to the ledge 93. l1owever, owing to the gap formed between the leaflet and arcuate wall sec~ion 82 adjacent to the ledge 93 a controlled leakage of blood past the leaflet is permitted in the closed position just sufficient to keep the blood agitated and avoid any ten-dency to clot or coagulate.
When blood flows under pressure into the heart and is applied to the upstream or convex surface 112 of the leafletl the opening pressure against the leaflet will cause its slide control members 114 to undergo a com-bination of sliding and pivotal movement from the position shown in full in Figure 16 to the dotted line position~
In undergoing both a l:imited sliding or translational ~ 1~3~
~ovement along with a pivotal movement through the guide pockets, the slide control members 11~ will advance from a position abutting the divergent edge 103 to an open posi~
tion abutting the edge L02. In moving to the open position, the leaflet will have undergone a movement of substantially 60 toward the arcuate wall section oE the valve body so as to form open passageways for the blood to flow both along the major and minor orifices and which passageways are free of any obstructions along opposed surfaces of the leaflets. Once again, by eliminating a fixed axis or point of rotation between the guide members and guide pockets, the blood or other liquid flowing therethrough can effec-tuate more complete washing action of the guide pockets while being free to pass to some extent between the side extensions and straight wall sections, thereby having the effect of a washing action on the mating surfaces between the slide control members 114 and guide pockets 98. When the direction of flow of blood is reversed, the fluid pressure will be applied to the concave surface 111 of each leaflet so as to cause the guide members 114 to undergo reverse movement through the guide pockets in an upstream direction until the leading edge of the leaflet returns into closed relation to the supporting ledge 93 and effec-tively checks the flow of blood in a reverse direction.
It is therefore to be understood that while pre-ferred and modified form of the invention have been set forth and disc:Losed herein that various modifications and changes may be made without departing from the spiri-t and scope of -the invention as defined by the appended claims.
Claims (16)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A prosthetic heart valve comprising:
an outer peripheral, generally annular body having an inner wall surface;
at least one leaflet disposed in said body, said leaflet including opposed lateral edge surfaces and leading and trailing edge surfaces; and leaflet-supporting means operative to sup-port said leaflet for movement in response to reversals in the direction of fluid flow through said body between an open position in which said leaflet is substantially parallel to fluid flow through said body and a closed position in which said leaflet extends angularly across said body, said leaflet-supporting means having lateral projections on opposed lateral edge surfaces elongated in a direction parallel to said lateral edge surfaces and guide pocket means for each of said lateral projections, each said guide pocket means disposed in the inner wall surface of said body between said leading edge surface and said trailing edge surface of said leaflet, each said guide pocket means aligned to receive one of said lateral projections whereby to guide pivotal and limited transla-tory movement of each said leaflet between said open and said closed positions in response to reversals in the direction of fluid flow through said body.
an outer peripheral, generally annular body having an inner wall surface;
at least one leaflet disposed in said body, said leaflet including opposed lateral edge surfaces and leading and trailing edge surfaces; and leaflet-supporting means operative to sup-port said leaflet for movement in response to reversals in the direction of fluid flow through said body between an open position in which said leaflet is substantially parallel to fluid flow through said body and a closed position in which said leaflet extends angularly across said body, said leaflet-supporting means having lateral projections on opposed lateral edge surfaces elongated in a direction parallel to said lateral edge surfaces and guide pocket means for each of said lateral projections, each said guide pocket means disposed in the inner wall surface of said body between said leading edge surface and said trailing edge surface of said leaflet, each said guide pocket means aligned to receive one of said lateral projections whereby to guide pivotal and limited transla-tory movement of each said leaflet between said open and said closed positions in response to reversals in the direction of fluid flow through said body.
2. A prosthetic heart valve according to claim 1, said opposed lateral edge surfaces being flat and extending substantially parallel to one another and movable into substantially sealed relation with respect to a correspondingly flat inner wall surface portion of said body when said leaflets are advanced to the closed position.
3. A prosthetic heart valve according to claim 1, said guide pocket means each being in the from of a shallow guide lane channel formed as a shallow depression in a flat inner wall surface portion of said body, said guide lane channel of each pair of guide lane channels on diametrically opposite sides of said body diverging away from one another at an acute angle from a point relatively near the leading edge surface of each respective leaflet.
4. A prosthetic heart valve according to claim 3, said opposed lateral edge surfaces of each leaflet being in the form of a skirt, said skirts extending substan-tially parallel to one another and to said flat inner wall surface portions of said body in a direction upstream of the direction of flow through said valve.
5. A prosthetic heart valve according to claim 1, said guide pocket means each being in the form of a shallow multi-sided guide channel of triangular con-figuration with opposite side edges divergent in a downstream direction and said lateral projections being of a length to be insertable in an associated channel and slidable through said channel between said opposite side edges.
6. A prosthetic heart valve according to claim 5, there being a pair of leaflets, each pair of said guide channels on opposite sides of each said leaflet being formed in axially directed extension in said valve body symmetrically about a plane passing through the longitudi-nal axis of said valve body and intermediately between each channel of a pair, each channel including a shallow recess having opposed sidewalls diverging away from one another in a downstream direction, each said lateral pro-jection being of a length corresponding to said opposite side walls.
7. A prosthetic heart valve according to claim 6, each of said lateral projections being free to undergo translational and pivotal movement in said channels in moving said occluder leaflets between the open and closed positions .
8. In an artificial heart valve according to claim 1, said valve body having an inner wall surface provided with a supporting ledge and the leading edge of said leaflet movable into contact with said supporting ledge in the closed position.
9. In an artificial heart valve according to claim 1, said leaflet having a major wall portion of concavo-convex configuration with its convex surface on the upstream side and having curved leading and trailing edge surfaces substantially corresponding to the curvature of the inner wall surface of said annular valve body.
10. In an artificial heart valve according to claim 8, said supporting ledge extending circumferentially of said inner wall surfaces for a distance corresponding to said leading edge surface and having a concave surface complementary to the convex surface of said leaflet.
11. In an artificial heart valve according to claim 1, said lateral projections being of narrow, elongated configuration and having gently curved external surfaces substantially along their length, said recesses provided with curved bearing surfaces complementary to the external surfaces of said lateral projections.
12. In an artificial heart valve according to claim 1, the included angle between opposed sidewalls of each recess being on the order of 40° to 60°.
13. A prosthetic heart valve comprising:
an annular valve body having an inner wall surface interrupted by diametrically opposed, straight wall sections, axially directed extensions disposed in diametrically opposed relation to one another and extending in a downstream direction from said straight wall sections of said body, each extension including a shallow recess of generally triangular configuration having opposed sidewalls diverging in a downstream direction; and at least one occluder leaflet disposed within said valve body, each leaflet having leading and trailing edge surfaces converging into opposed lateral edge surfaces, each lateral edge surface extending parallel to and coextensive with one of said straight wall sections and each having a lateral projection inserted into a recess in one of said axial extensions, each said lateral projection being of a length corresponding to the length of a sidewall of said recess and of a width less than the space between said sidewalls, each pair of lateral projections defining guide means operative to control movement of said leaflet between an open position in which said leaflet is disposed substantially parallel to said valve body and a closed position in which said leaflet is disposed for extension angularly across said valve body.
an annular valve body having an inner wall surface interrupted by diametrically opposed, straight wall sections, axially directed extensions disposed in diametrically opposed relation to one another and extending in a downstream direction from said straight wall sections of said body, each extension including a shallow recess of generally triangular configuration having opposed sidewalls diverging in a downstream direction; and at least one occluder leaflet disposed within said valve body, each leaflet having leading and trailing edge surfaces converging into opposed lateral edge surfaces, each lateral edge surface extending parallel to and coextensive with one of said straight wall sections and each having a lateral projection inserted into a recess in one of said axial extensions, each said lateral projection being of a length corresponding to the length of a sidewall of said recess and of a width less than the space between said sidewalls, each pair of lateral projections defining guide means operative to control movement of said leaflet between an open position in which said leaflet is disposed substantially parallel to said valve body and a closed position in which said leaflet is disposed for extension angularly across said valve body.
14. In a prosthetic heart valve according to claim 13, there being a single leaflet of a size corresponding substantially to the opening in said annular valve body, said inner wall surface of said valve body provided with a curved supporting ledge portion to support said leaflet in the closed position.
15. In a prosthetic heart valve according to claim 14, said leaflet being generally elliptical in cross-section and terminating on opposite lateral sides in laterally extending marginal walls, each of said axial extensions being flat and projecting downstream from one end of each said flat wall sections of said valve body.
16. In a prosthetic heart valve according to claim 13, each of said axially directed extensions having a flat wall section forming an axial continuation of a flat wall section along the inner wall sections of said annular valve body, each said axial extension having a generally convex downstream edge.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US14403480A | 1980-04-28 | 1980-04-28 | |
| US144,034 | 1980-04-28 | ||
| US21384480A | 1980-12-08 | 1980-12-08 | |
| US213,844 | 1980-12-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1163054A true CA1163054A (en) | 1984-03-06 |
Family
ID=26841619
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000376177A Expired CA1163054A (en) | 1980-04-28 | 1981-04-24 | Artificial heart valve |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1163054A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4995881A (en) * | 1988-08-25 | 1991-02-26 | B. Braun Melsungen Ag | Heart valve prosthesis |
-
1981
- 1981-04-24 CA CA000376177A patent/CA1163054A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4995881A (en) * | 1988-08-25 | 1991-02-26 | B. Braun Melsungen Ag | Heart valve prosthesis |
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| Date | Code | Title | Description |
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| MKEX | Expiry |