FR2462149A1 - PROSTHESIS OF HEART VALVE - Google Patents

Abstract

ARTIFICIAL HEART VALVE WITH ANNULAR BODY CROSSED BY A PASSAGE CONTROLLED BY TWO VALVES. EACH VALVE IS ARTICULATED BY ELEMENTS ENGAGED ON THE OPPOSITE IN THE ANNULAR BODY 13. THIS BODY HAS AN ARCHED SEAT 47 WITH A SURFACE DIRECTED DOWNSTREAM AND EACH VALVE PRESENTS A LARGE ARCED EDGE 31 THAT CAN BE HERMETICALLY APPLIED AGAINST THE INNER FACE DUDIT BODY AND A SMALL STRAIGHT EDGE 29. IN THE CLOSED POSITION, THE VALVES START WITH THEIR UPSTREAM SIDES AGAINST THE DOWNSTREAM FACE OF THE SEAT AND THEIR STRAIGHT-LINE SLICES START POSITIVELY AGAINST ANOTHER IN A DIAMETRAL PLANE OF THE PASSAGE . THE VALVES AND SEATS ARE DESIGNED SO THAT THE LOAD WILL STOP APPLYING TO THE HINGE RAILS IN THE CLOSED POSITION, WHICH MINIMIZES WEAR.

Description

The present invention relates to cardiac valve prostheses for

  substitute for defective natural valves and, more specifically, for heart valve prostheses

having two hinged flaps.

  Various types of heart valve prostheses have been developed whose hemodynamic function derives from the pumping effect exerted by the heart and which essentially functions as check valves. Of the valves of this type that have been used, some have a ball in a cage and others have a valve in the shape of a

  disk. US Patent 3,534,411 issued October 20, 1970 discloses

  wrote an example of a valve with a disk of the

  so freely. A number of pivoting disc valves, such as those described in US Pat. Nos. 3,546,711 (Bokros) granted on December 15, 1970, have also been developed.

  and 3,859,668 granted on January 14, 1975.

  Cardiac valves of the type to be dis-

  that, instead of a single disc, two valves or lo-

  which rotate around parallel axes to ensure

  vertex and closing of the valve. GB 1 160 008 granted July 30, 1969, gives an example of such a valve; it's this kind of heart valve prosthesis that

relates to the present invention.

  The invention provides improvements to prostheses

  heart valve having two lobes or flaps

  supported by means embroiled in one another in

  an annular valve body with a generally circumscribed section

  lar. There is a double curved seat, with a direct surface

  downstream, incorporated in the inner face of the wall of the annular valve body. The flaps each have a small straight edge and a large arcuate edge and the face

  upstream of the arcuate edge abuts against the downstream face of the

  whereas, whereas flat slices have small

  lines stumble against each other. The valve has the

  the means embroidered into each other cease to be under load when the flaps are closed,

  which improves the wear resistance at the points of interest

  his. By associating each valve with a relatively long arched seat, excellent sealing is achieved both in the middle and Z46t241 along the periphery, which greatly reduces the reflux occurring through the retaining valve during its times.

closing.-

  Two examples will now be described as examples

  preferred embodiments of the invention with reference to the accompanying drawings, in which:

  FIG. 1 is a perspective view of a valve

  diaque having various aspects of the invention and provided with two valves shown in the open position; Figure 2 is a sectional view taken along line 2-2 of Figure 1; Figure 3 is a detail sectional view, similar to Figure 2, showing the valves in closed positions; FIG. 4 is a broken-away plan view of the

  valve according to FIGS. 1 to 3, showing the valves in

  closing conditions; Figure 5 is, on a larger scale, a sectional view along the line 5-5 of Figure 3;

  FIG. 6 illustrates in a variant a variant of

  heart valve according to the invention, comprising two

  presented in open positions; Figure 7 is a detail sectional view along the line 7-7 of Figure 6; Figure 8 is a sectional view similar to Figure 7, showing the closed valves; FIG. 9 is a plan view, on a slightly scale

  reduced, the valve shown in Figure 8, the clas-

pets being closed;

  FIG. 10 is a detailed perspective view, exploding

  the valve shown in FIG. 6, illustrating the relationship between the valves and the valve body; Figure 11 is a detail view in section along the line 11-11 of Figure 9;

  FIG. 12 is, on a larger scale, a view of

  tail section along the line 12-12 of Figure 8.

  Fig. 1 shows, by way of example, a heart valve 11 having an annular valve body 13 which carries two lobed, pivoting valves 15 which can open and close to control blood flow through a passageway. central 17. The normal direction of flow

  blood is that indicated by arrows 19 in Figure 2.

  The valves 15 are articulated around eccentric pins mounted in two diametrically opposed uprights 21 which

  stand up on the annular valve body 13.

  It goes without saying that the valve It can work with any orientation because it is not significantly affected by gravity; however, to fix the ideas, we suppose,

  in the present description, the valve 11 oriented so

  that the uprights 21 stand up on the body of

Annular valve 13.

  The valve body has a peripheral groove

  23, surrounding its outer face, intended to receive one year

  suture (not shown) which may be of any

  various types already known to those skilled in the art.

  The suture ring facilitates joining by seaming or suturing the heart valve to the heart tissue. The passage 17 which passes through the valve body 13 is preferably circular and the inner face 25 of the body 13 which defines this passage

  is in the general shape of a straight cylinder.

  The valve body 13 is the valves 15 may be of any suitable material that is biocompatible and non-thrombogenic and likely to withstand the wear suffered by these elements during innumerable movements of opening and

  closing the flaps. These components may be in graphi-

  isotropic, as sold under the trade name POCO, having been suitably coated with pyrocarbon, preferably that sold under the trade name PYROLITE which ensures

  excellent degree of compatibility and resistance to

  re. The valves 15 shown by way of example are flat and have a uniform thickness in all their points. The small edge 29 of each flap is rectilinear and offers a flat slice; the large edge 31 has the desired curvature to fit the inner face of the passage 17. The outline of the large arcuate edge 31 is defined by a plane obliquely intersecting the cylindrical inner face 25 of the valve body, and is therefore elliptical. The slope of the flat edge of the small edge 248t149

  29 on the flat faces of the valve 15 is determined by means of

  that the two straight slices are almost completely in surface contact when the flaps are closed (figure

  3), as will be explained later in detail.

  Each of the uprights 31 has two spherical depressions 33 receiving lugs 35 which project on either side of the valves 15. The end slices 37 of the lugs 35 are spherical surface portions whose radius of curvature is equal or any just lower (by

  for example, about 1 to 2%) to the radius of curvature of

  Thus, the spherical ears and depressions are interengaged means which guide the pivoting movement of the valves and define the eccentric hinge axes around which the valves pivot. However, instead of the lateral thrusts generated by the valves being supported by the ears, there are provided surfaces or slices of flat supports 39 between the ears and the small flat edges 29, and the

  two flat surfaces 39 juxtaposed bear against a surface

  this plate 41 provided on the portion directed towards the inside of each upright 21. Each ear 35 has the desired width to

  that its summit does not quite reach the wall of the

  spherical pressure 33, as shown in FIG.

  Each amount 21 also has two facets 43

  pendicular to the flat surface 41 and which offer stops

  valves in open positions.

  As can be seen in FIG. 2, when the valves have pivoted during their opening movements so that their main parts have tilted up and down downstream, the parts of the upstream faces 45 of the neighboring flaps

  flat slices of the small edges 49 come to bear

  be the stops 43, thus stopping the opening movements of the valves when they have the orientations indicated in - Figure 2. Since in these open positions,

  the flaps are almost parallel to the flow direction

  blood flow down through the passage 17, the bearing force of the valves 15 on the abutments 43 is low, so

  that wear at this level does not raise any problem.

  In order to ensure watertightness along the long, arti-

246214th

  31 of each flap in the closed and improved position.

  longevity and operative characteristics of the valve, an arched console or

  diametrically opposed regions of the valve body 13.

  In the example illustrated, the inner face 25 of the

  annular body to provide this seat 47, which is sensitive

  elliptical to marry the elliptical arched edge 31 of the flapper

  associated. The edge of each flap that connects the faces of

  upstream and downstream flat along the large edge 31 has preferably

  it has a slightly lower radius of curvature, for example from 2 to 5%, to the corresponding radius of curvature of the arcuate face of the seat 47. This relationship ensures, in the closed position, a linear contact which minimizes the reflux leakage on the

along the long edges of the flaps.

  As can be seen from FIG. 2, the passage 17 has a smaller diameter upstream than downstream of the seat 47 and this seat 47 is situated so as to act in abutment with respect to the valves in the position of closing. Due to its location, the seat 47 also provides another result, which is to remove the load on the ears 35, in the closed position,

  substantially eliminating the contact between the spherical surfaces

  33 and the spherical surfaces 37 of the ears. When the valves 45 pivot towards the closed position, their large edges 31 come into contact with the

  curved surface 47 of the seat, which stops their pivotal movement.

  voting. If the flat slices 29 of the flaps are then in contact, the flaps no longer describe any movement; if on the other hand there is a slight gap between these flat slices, because of the tolerance provided between the ears 35 and the depressions 33, the back pressure exerted by the blood against the lower flat faces or downstream of the valves has the effect to quickly bring them one stop against

  the other by a slight slippery movement, authorized by the

  bowed out of the regions of contact with the seats 47. The

  the desired structure so that the downstream faces of the clusters

  farts, in closed positions, an angle of approximately

  at 800 with a plane passing through the axis of the passage.

  The seat 47 occupies, relative to the depressions 33, a location such that the ears 35 are quite precisely t46t1U

  centered in depressions 33. As a result, and as

  tré by figure 5, there are slight interstices between

  the terminal slices 37 of the ears and the spherical surfaces

  33 depressions. This is the removal of the physical contact normally occurring between these surfaces when the valves are open or being pivoted between open and closed positions which eliminates wear at the time of the cycle o it is likely to be maximum, c that is to say,

  when the flaps move while they are almost

  and that the pressure difference between the two sides of

the valve is approaching the maximum.

  In this position, shown in FIG.

  Blood pressure which is exerted on the downstream faces of the valves 15 generates forces which can be decomposed into vectors directed in two directions: according to the planes of the valves and perpendicular to these planes. the

  vector forces act in the planes of

  the contact of the two small flat edges 29 abutting one

  to be the other. Forces perpendicular to the plane of the valves

  resists the abutment contacts against the arcuate faces di-

  downstream of Seat 47, established all along the

big edges 31.

  Since the downstream faces of the valves 15 are almost completely exposed to the blood pressure, the forces exerted by it are evenly distributed.

  on these sides, and the arched seat is placed so as to resist

  to these forces so that they are not supported by the ears in contact with the surfaces of the spherical depressions 33, on which the wear would concentrate. To obtain this result, it is important that the surfaces of the seat 47 are located so as to be cut by a parallel to the axis of rotation defined by the lugs 35 which divides the downstream face into two regions of areas equal, this

  parallel being called the "surface axis" of the flaps and

  shown by the symbol AS in FIG. 4. It can be seen that this axis AG cuts the seat 47. The effect of this relationship is indicated for the left valve in FIG. 4, on which a line S connecting the ends of the associated arched seat , and that divides

  the surface of the flap in regions A1 and A2, extends interior-

  relative to the AS axis. Although indicated on the upstream face which is visible in FIG. 4, this relation is the same on the downstream face, which is the important face as regards this aspect. The area of the region A1 is greater than that of the region A2 and the contact established between the valve and its seat along the region A resists the force exerted by 1. the blood pressure against the valve and removes the

  the load on the ears 35 in the spherical depressions

33.

  Figures 6 to 12 show by way of example a

  heart valve 51 which generally resembles the valence

  vule 11, but has another valve hinge arrangement and a slightly different seat arrangement assigned to each large valve edge. Valve 51 has an annular valve body 53 and two valves 55 which control

  the flow of blood circulating, normally following the arrow

  59 of Figure 7, through a central passage 57.

  that valve 55 has two ears 61 which penetrate into depressions of generally triangular shape 63 formed

  in uprights 65 erected upwards.

  The passage 57 which passes through the valve body is defined

  nor by the inner wall face 67, substantially shaped

  right cylinder, interrupted only in the region of

  65 and in that of the arcuate seats 69 that will be described.

  The valves 55 are flat and of uniform thickness, their

  turns being defined by the edge of a small flat edge 51 and the edge of a large arcuate edge 73. Again, the large edge 73 has substantially the shape defined by the intersection of a plane with the right cylinder. The edge of the large edge 73 is rounded so as to come into substantially linear contact

  with the cylindrical inner face.

  The axis of articulation of each valve is also eccentric

  than with respect to the valve, being defined by the ears 61,

  each of which has a section of generally

  gullet and rounded corners and edges. The lower end

  of each ear has an appropriate radius of curvature

  facilitates its pivoting movement in the depression 63 and

  finishes the axis of articulation of the valve. The depressions 63 pre-

  have preferably flat and complementary bottoms 75 to flat end slices 77 formed on the ears

  (see Figure 12); however, it is also possible to

  complementary arcuate faces. As in the valve 11, the ears 61 are dimensioned so that there is only a very small gap between the flat end portion 77 of an ear and the bottom 75 of the associated depression. As a result, each valve has short surfaces

  flat support 79 (see Figure 10) in its region

  each ear 61 and the small straight edge 71, and

  immediately below the ears, these surfaces of

  bearing against the flat inner faces 81 of the

amounts 65.

  The perimeter of each depression 63 has an arcuate upper edge & 3 which connects rectilinear, outer 85 and inner 87 edges. The straight edges 85 and 87 converge towards a rounded rounded vertex whose radius of curvature substantially matches that of the end. lower ear 61, to form the desired articulation surfaces. Preferably, the radius of curvature of said vertex is not more than 3% greater than the radius of curvature of the lower end of the ear. The distance from said vertex to the arcuate upper edge 83 is chosen so as to establish a

  sufficient clearance to allow the ear to move freely

  in depression 63, this game representing, for example,

  about 5% of the length of the ear.

  The outer edge 85 of each depression 63 provides a

  associated valve stop in the open position

  Figure 7. In this position, blood flows up and down through the valve and the lower end.

  of the ear 61 leans against the vertex or returns pre-

  city. Because the valves 55 are, in this position, almost parallel to the direction of flow of the blood, there is hardly any force tending to apply the ear 61

  against the rectilinear depression edge 85, and the wear can not

no problem.

  At the end of the systole, the ventricle concerned relaxes

  to draw more blood into its cavity 3 from

  the aperture of the atrium and, under the effect of the counter-pres-

  in the aorta, the valves of a valve in a posi-

t462149

  the aortic area begin to pivot towards the closed position.

  With the orientation shown in Figure 7, the force

  that exerts by the blood trying to go back on the most part

  The portion of the area of the downstream face 89 of each valve, located below the hinge axis, makes the flaps swing outwardly. The arched upper facet 83 guides the movement described by the arched upper edge of

  associated ear 61, since the lower ends

  the ears tend to rise above the

  above mentioned during the pivoting closing movement.

  To stop the valves in closed positions, it

  is provided the four stops 69, judiciously distributed over

  turn of the inner face 67 of the valve body. Each of the stops 69 has a lower face 91 directed by a

  generally downstream and arched with a radius of cur-

  slightly higher than that of the upstream face of the large

  edge 73 of each flap, so as to make linear contact with each

  the position of the faces 91 is such that, when a contact is established between the arcuate parts directed upstream of the

  large curved edges 73 of the valves and the downstream surfaces ar-

  As abutments, the flat edges of the small edges 71 are pressed against each other, which positively avoids

  blood infiltrations according to the diameter of the junction

  valves and also eliminates the contact between

  upper arched ears 79 and facets ar-

83 of the depressions.

  The stops 69 are judiciously placed so as to

  cut off by the parallel to the axis of articulation which

  targets the downstream face 89 in two regions of equal areas, again

  indicated by the signal AS in Figure 9. Thanks to the position

  of the stops 69, there are

  91, directed downwards, which flank the points of intersection between the axis AS of each valve and the

  thrust and, as a result, the force exerted by the counter-pressure

  bloodstream on the downstream face 89 of each valve is sup-

  carried by the lower faces 91 of the stops. If it were

  otherwise, the component of the blood pressure counter-pressure

  perpendicular to the surface of each flat flap t46t149

  would be supported by contact appearing between each

  the, near its curved lower end, and the ex-

  rectilinear inner 85 of each depression, which would have a strong tendency to cause wear. On the valve located on the right in FIG. 9, a straight line S is further traced which connects the inner ends of the stops 69 and divides

  the valve in regions A1 and A2. Because the area of the

  A1 is greater than that of region A 2, the force

  plicated by the blood pressure on the underside of the

pet is supported by the stops.

  In general, the provisions described are

  various modifications without departing from the scope of the invention. For example, although it is preferable

  to arrange the depressions in flat parts of the pa-

  inner king of the valve body and shape the oreil-

  protruding on the side edges of the valves, we can invert these formations engaged one into the other and thus protect the depressions in the side edges of the valves, shaping the ears at opposite points on the opposite flat parts of the body of valve. In addition, the invention is not limited to flat valves and can be applied in a similar manner to a valve comprising

two curved flaps.

1l

Claims (12)

  Heart valve prosthesis, characterized in that it comprises:   an annular valve body 13,53 crossed by a step   with a generally circular cross-sectional shape, two valves 15, 55 sized to interrupt blood flow through said passage when in their closed positions, said valve body having a common seat 47, 69 arcuate with a surface directed to generally downstream, with respect to the normal direction of blood flow through said body, each of said valves having a large arcuate rim 31, 73 abutting the surface of said seat and a small flat slice edge 29 , 71 and   33,35,61,63 means embroiled in one another which ar-   tilting each of said valves in said valve body so that it can pivot relative to that body between its closed and open positions,   each of said valves 15, 55 having, in a closed position,   ture, an orientation such that its downstream face makes an acute angle with the axis of said passage, so that, under the effect of blood pressure, said small edges abut one against   the other and positively close the said passage according to his   diane while said large edges bear against said seat, and said seat 47, 69 being placed so that the force   applied by the blood pressure back to said means   in each other ceases to be exercised when the said   Pets reach their closed positions, so that wear on said engaged means is minimized.   2. Heart valve according to claim 1, characterized   in that the contour of said arched edge 31, 73 of the valve is substantially that defined by the intersection of a plane with a cylindrical surface.   3. Heart valve according to claim 1, characterized   in that said downstream face 47,91 of said   ge has a predetermined radius of curvature and in that said large arcuate edge 31,73 has, in the region where it abuts against   said seat, a smaller radius of curvature.   4. Heart valve according to claim 3, characterized   in that the contour of said edge 31, 73 is elliptical.   Heart valve according to claim 1, characterized   in that in said closed position, said downstream faces 47, 91 have an inclination of about 45 to 800 on   a plane passing through the axis of said passage.   Heart valve according to claim 1, characterized   in that separate arcuate seats 47 are provided,   placed in diametrically opposite positions along the   this interior of said annular valve body and intended for   come into abutting contact with a major part of the   the arched edge of each flapper.   7. Heart valve according to claim 6, characterized   in that each of said separate arcuate seats 47 extends   up to the intersections of the surface axis AS of the flap valve   with the inner face of said valve body.   8. Heart valve according to claim 1, characterized   in that said common seat comprises. two seats 69   each of which is associated with one of the valves at the points of intersection of the surface axis AS of the downstream face with said annular body.   9. Heart valve according to claim 8, characterized   in that the upstream region of said arcuate flap edge 73   has a radius of curvature slightly less than the radius of curvature   bure of the downstream face of said seat.   10. Heart valve according to claim 1, characterized   in that the said means engaged in each other   have two protuberances 35,61 from opposite lateral sides   placed said valves and which penetrate into depressions 33, 63 approximately diametrically opposite formed in the face   interior of said annular valve body.   11. Heart valve prosthesis, characterized in that it comprises an annular valve body 53 traversed by a central passage, two lids or valves 55,   support means articulating said check valves   that they can pivot about eccentric axes between a closed position in which blood flow through said central passage is prohibited and an open position in which this flow is permitted, said valves each having protruding guides 61 in opposite directions along the axis of articulation, these guides having a rounded lower end,   said support means including pairs of   pressures 63 of generally triangular shape located at approximately diametrically opposite locations, each of these depressions having an upper edge   arched 83 and outer and inner edges 85,87 general-   rectilinear which meet at a vertex or reentrant, said valve guides being inserted into these depressions, their aforementioned lower ends being located in said recesses of these depressions, each of these re-entrant   having a radius of curvature that is consistent with the radius of curvature   bure said lower ends and providing hinge points at the associated lower end, so that   each of said flaps moves between an open position   in which said guides are adjacent said outer edges and a closed position in which these   guides are adjacent to said inner edges.   12. Prosthesis according to claim 11, characterized in that the radius of curvature of said reentrant is equal or not   greater than 3 M in the radius of curvature of that end lower half.