Note: Descriptions are shown in the official language in which they were submitted.
~ ~3~
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 -- !
~ ~3~
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
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~ 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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..~,.,
~ :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
-- 10 --
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
- 13 -
~ 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
- 15 -
~ :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 ~.
- 16 -
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.
- 17 -
~ ~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
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~ ~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.
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