Heart valve prosthesis

Claim 2

A heart valve prosthesis comprising: a base having an inside annular wall surrounding a passage for carrying blood through the base, means for connecting the base to heart tissue, valving means located in the passage for controlling the flow of blood through the passage, said valving means comprising a first valving member having a convex curved leading edge and a transverse trailing edge, and a second valving member having a convex curved leading edge and a transverse trailing edge, first pivot means pivotally connecting the first member to the base for movement about a first axis offset in one direction from the center of the passage, second pivot means pivotally connecting the second member to the base for movement about a second axis offset in the direction opposite the one direction from the center of the passage, a first side member on the base projected in the direction of the flow of blood through the passage, a second side member on the base projected in the direction of the flow of blood through the passage, said second side member being opposite the first side member, each side member having first stop means engageable with the first valving member and second valving member to hold the first valving member and second valving member in inclined closed positions to restrict the flow of blood in one direction through the passage, and second stop means on the base engageable with the first valving member and the second valving member when the valving members are in their open positions.

Claim 3

The prosthesis of claim 1 wherein: the first valving member and second valving member are inclined toward each other when in their closed positions.

Claim 4

The prosthesis of claim 2 wherein: the inclination is about 45° from the transverse plane of the passage.

Claim 5

The prosthesis of claim 1 wherein: each side member has an inside surface coextensive with the inside annular wall of the base.

Claim 6

The prosthesis of claim 1 wherein: the first stop means comprise inclined and converging lip portions providing seats engageable with parts of the valving members when the valving members are in their closed positions:

Claim 7

The prosthesis of claim 1 wherein: the second stop means comprise projections extended from the base engageable with parts of the valving members when the valving members are in their open positions.

Claim 8

The prosthesis of claim 1 wherein: each side member has a generally triangular shape.

Claim 9

The prosthesis of claim 1 wherein: each valving member has a leading edge having a thickness about twice the thickness of the trailing edge, and generally flat side surfaces between the leading and trailing edges.

Claim 10

The prosthesis of claim 1 wherein: each valving member is substantially balanced on its respective pivot means.

Claim 11

The prosthesis of claim 1 wherein: the side members are located between the first axis and the second axis.

Claim 12

The prosthesis of claim 1 wherein: the transverse trailing edges of the valving members are spaced apart when the valving members are in their closed positions.

Claim 13

The prosthesis of claim 1 wherein: each valving member has outer peripheral edges spaced from the inside wall to allow limited reverse flow of blood between the valving members and the base when the valving members are in the closed positions.

Claim 14

The prosthesis of claim 1 wherein: the means for connecting the base to heart tissue includes a sleeve, and coacting means on the base and sleeve allowing the base to be removed from the sleeve after the means is connected to the heart tissue.

Claim 15

The prosthesis of claim 1 wherein: the first pivot means and the second means each includes pivot axles secured to opposite side edges of the first and second valving members, said pivot axles being located along a transverse pivot axis parallel to the linear trailing edges of the valving members, said transverse pivot axis being spaced from the midportions of the leading edges and trailing edges of the members.

Claim 16

The prosthesis of claim 14 wherein: the distance from the pivot axes to the midpoint of the trailing edge is about twice the distance from the pivot axis to the midpoint of the leading edge .

Claim 17

The prosthesis of claim 1 wherein: the means for connecting the base to heart tissue includes a sleeve having a cylindrical inside wall, an inside threaded section and an inside shoulder between the inside wall and the inside threaded section, said base having an outside wall and an outside threaded section and a shoulder between said outside wall and and outside threaded section, said inside and outside walls, threaded sections and shoulders engaging each other when the base is mounted on the sleeve, said sleeve having an outside annular channel, a suturing collar located in the channel adapted to be secured to heart tissue, and releasable lock means mounted on the sleeve and engageable with the base to fix the position of the base on the sleeve, said lock means having a lock position to fix the location of the base on the sleeve and a release position allowing the base to be mounted on and removed from the suturing means after the suturing means is attached to the heart tissue.

Claim 18

The prosthesis of claim 1 wherein: the means for connecting the base to heart tissue includes a sleeve, coacting means on the base and sleeve allowing the base to be removed from the sleeve after the means is connected to the heart tissue, and lock means for locking the sleeve on the base, said lock means being movable to a release position to allow the base to be removed from the sleeve without removing the sleeve from the heart tissue.

Claim 19

The prosthesis of claim 1 wherein: the first pivot means includes a first pair of pivot members secured to the base and projected into the passage and a second pair of pivot members secured to the base and projected into the passage, each pair of pivot members having one pivot member located adjacent one side of the first valving member and a second pivot member located adjacent the opposite side of the first valving member, and means on the first valving member cooperating with a pivot member of each pair of pivot members to control the the pivotal movement of the first valving member and retain the first valving member in assembled relation with the base, the second pivot means includes a first pair of pivot members secured to the base and projected into the passage and a second pair of pivot members secured to the base and projected into the passage, each pair of the pivot members of the second pivot means having one pivot member located adjacent one side of the second valving member and another pivot member located adjacent the opposite side of the second valving member, and means on the second valving member cooperating with a pivot member of each pair of pivot members of the second pivot means to control the pivotal movement of the second valving member and retain the second valving member in assembled relation with the base.

Claim 20

The prosthesis of claim 18 wherein: the means on the first valving member comprise a pair of ears on opposite side portions of the first valving member, and the means on the second valving member comprise a pair of ears on opposite side portions of the second valving member.

Claim 21

The prosthesis of the claim 1 wherein: the base has first and second semi-circular segments, and annular means holding the segments in a circular arrangement.

Claim 22

The prosthesis of claim 20 wherein: the first pivot means includes a first pivot member on the first segment and a second pivot member on the second segment, and the second pivot means includes a first pivot member on the first segment and a second pivot member on the second segment.

Claim 23

A heart valve prosthesis comprising: a base having an inside annular wall surrounding a passage for carrying blood through the base, valving means located in the passage movable to open and closed positions for controlling the flow of blood through the passage, said valving means comprising a first valving member having a convex curved leading edge and a transverse trailing edge, and a second valving member having a convex curved leading edge and a transverse trailing edge, first pivot means pivotally associating the first member with the base, said first pivot means having fulcrum portions engageable with the first valving member for controlling the movement of the first valving member in a location offset in one direction from the center of the passage, second pivot means pivotally associating the second member with the base, said second pivot means having fulcrum portions engageable with the second valving member for controlling the movement of the second valving member in a location offset in the direction opposite the one direction from the center of the passage, a first side member on the base projected in the direction of the flow of blood through the passage, a second side member on the base projected in the direction of the flow of blood through the passage, said second side member being opposite the first side member, each side member having first stop means engageable with the first valving member and second valving member to hold the first valving member and second valving member in inclined closed positions to restrict the flow of blood in one direction through the passage, and said first and second pivot means having second stop means on the base engageable with the first valving member and the second valving member when the valving members are in their open positions.

Claim 24

A heart valve prosthesis comprising: a base having an inside annular wall surrounding a passage for carrying blood through the base, valving means located in the passage movable to open and closed positions for controlling the flow of blood through the passage, said valving means comprising a first valving member having a convex curved leading edge and a transverse trailing edge, and a second valving member having a convex curved leading edge and a transverse trailing edge, first pivot means pivotally associating the first member with the base, said first pivot means having fulcrum portions engageable with the first valving member for controlling the movement of the first valving member in a location offset in one direction from the center of the passage, second pivot means pivotally associating the second member with the base, said second pivot means having fulcrum portions engageable with the second valving member for controlling the movement of the second valving member in a location offset in the direction opposite the one direction from the center of the passage, a first side member on the base projected in the direction of the flow of blood through the passage, a second side member on the base projected in the direction of the flow of blood through the passage, said second side member being opposite the first side member, each side member having first stop means engageable with the first valving member and second valving member to hold the first valving member and second valving member in inclined closed positions to restrict the flow of blood in one direction through the passage, and said first and second pivot means having second stop means on the base engageable with the first valving member and the second valving member when the valving members are in their open positions.

Claim 25

The prosthesis of claim 22 wherein: the first valving member and second valving member are inclined toward each other when in their closed positions.

Claim 26

The prosthesis of claim 22 wherein: each side member has an inside surface coextensive with the inside annular wall of the base.

Claim 27

The prosthesis of claim 22 wherein: the first stop means comprise inclined and converging lip portions providing seats engageable with parts of the valving members when the valving members are in their closed positions.

Claim 28

The prosthesis of claim 22 wherein: each valving member has a leading edge having a thickness about twice the thickness of the trailing edge, and generally flat side surfaces between the leading and trailing edges.

Claim 29

The prosthesis of claim 22 wherein: the transverse trailing edges of the valving members are spaced apart when the valving members are in their closed positions.

Claim 30

The prosthesis of claim 22 wherein: each valving member has outer peripheral edges spaced from the inside wall to allow limited reverse flow of blood between the valving members and the base when the valving members are in the closed positions.

Claim 31

The prosthesis of claim 22 wherein: the first pivot means and the second pivot means each includes first and second pairs of pivot members on the base and ears on the valving members associated with the pairs of pivot members cooperating with a pivot member of each pair of pivot members to control the movement of the valving members.

Claim 32

The prosthesis of claim 22 wherein: the base has first and second semi-circular segments, and annular means holding the segments in a circular arrangement, said first pivot and second pivot means each having a first pivot member on the first segment and a second pivot member on the second segment.

Claim 33

A heart valve prosthesis comprising: a base having first and second semi-circular segments defining an inside annular wall surrounding a passage for carrying blood through the base and annular means holding said segments in circular arrangement, valving means movable to open and closed positions for controlling the flow of blood through the passage, said valving means comprising a first valving member and a second valving member, means cooperating with the valving members for controlling the opening and closing movements of the valving members and retaining the valving members in operative assembled relation with the base, said means cooperating with the valving members including first pivot means movably associating the first valving member with the base, said first pivot means having first and second pairs of pivot members secured to the base and engageable with separate portions of the first valving member, said first valving member having means cooperating with the first and second pairs of pivot members to retain the first valving member in assembled relation with the base, second pivot means movably associating the second valving member with the base, said second pivot means having first and second pairs of pivot members secured to the base and engageable with separate portions of the second valving member, said second valving member having means cooperating with the first and second pair of pivot members of the second pivot means to retain the second valving member in assembled relation with the base, said first pairs of pivot members of the pivot means being joined to said first segment and said second pairs of pivot members of said pivot means being joined to said second segment and side members on the base projected in the direction of flow of blood through the passage, said side members having stop portions engageable with the first and second valving members when said first and second valving members are in their closed positions.

Claim 34

A heart valve prosthesis comprising: a base having first and second semi-circular segments defining an inside annular wall surrounding a passage for carrying blood through the base and annular means holding said segments in circular arrangement, valving means movable to open and closed positions for controlling the flow of blood through the passage, said valving means comprising a first valving member and a second valving member, means cooperating with the valving members for controlling the opening and closing movements of the valving members and retaining the valving members in operative assembled relation with the base, said means cooperating with the valving members including first pivot means movably associating the first valving member with the base, said first pivot means having first and second pairs of pivot members secured to the base and engageable with separate portions of the first valving member, said first valving member having means cooperating with the first and second pairs of pivot members to retain the first valving member in assembled relation with the base, second pivot means movably associating the second valving member with the base, said second pivot means having first and second pairs of pivot members secured to the base and engageable with separate portions of the second valving member, said second valving member having means cooperating with the first and second pair of pivot members of the second pivot means to retain the second valving member in assembled relation with the base, said first pairs of pivot members of the pivot means being joined to said first segment and said second pairs of pivot members of said pivot means being joined to said second segment and side members on the base projected in the direction of flow of blood through the passage, said side members having stop portions engageable with the first and second valving members when said first and second valving members are in their closed positions.

Claim 35

The prosthesis of claim 31 wherein: the first valving member and second valving member are inclined toward each other when in their closed positions.

Claim 36

The prosthesis of claim 31 wherein: the stop portions comprise inclined and converging lip portions providing seats engageable with parts of the valving members when the valving members are in their closed positions.

Claim 37

The prosthesis of claim 31 wherein: each side member has a generally triangular shape.

Claim 38

The prosthesis of claim 31 wherein: each valving member has a leading edge having a thickness about twice the thickness of the trailing edge, and generally flat side surfaces between the leading and trailing edges.

Claim 39

The prosthesis of claim 31 wherein: each valving member is substantially balanced on its respective pivot means.

Claim 40

The prosthesis of claim 31 wherein: each valving member has outer peripheral edges spaced from the inside wall to allow limited reverse flow of blood between the valving members and the base when the valving members are in the closed positions.

Claim 41

The prosthesis of claim 31 wherein: the first valving member pivots about a first location offset from the center of the passage and the second valving member pivots about a second location offset from the center of the axis, said first and second locations being located on opposite sides of the center of the passage and extended generally parallel to each other.

Claim 42

The prosthesis of claim 38 wherein: the side members are located between the first location and the second location.

Claim 43

A valving member for a heart valve prosthesis comprising: a semi-elliptical shaped member having a convex curved leading edge, a transverse linear trailing edge, arcuate side edges connecting the opposite sides of the leading edge to opposite ends of the trailing edge and generally flat side surfaces extended from the leading edge to the trailing edge.

Claim 44

A valving member for a heart valve prosthesis comprising: a semi-elliptical shaped member having a convex curved leading edge, a transverse linear trailing edge, arcuate side edges connecting the opposite sides of the leading edge to opposite ends of the trailing edge and generally flat side surfaces extended from the leading edge to the trailing edge.

Claim 45

The valving member of claim 40 including: pivot axles secured to opposite side edges of the member, said pivot axles located along a transverse pivot axis parallel to the linear trailing edge, said pivot axis being spaced from the midportions of the leading edge and trailing edge.

Claim 46

The valving member of claim 41 wherein: the distance from the pivot axis to the midportion of the trailing edge is about twice the distance from the pivot axis to the midportion of the leading edge.

Claim 47

The valving member of claim 40 wherein: said side surfaces taper toward each other from the leading edge to the trailing edge of the member.

Claim 48

The valving member of claim 40 including: a pair of ears projected outwardly from separate portions of the side surfaces of the member, said ears being located adjacent opposite portions of the side edges of the member.

Claim 49

The valving member of the claim 44 wherein: each ear has a trailing face extended generally parallel to the transverse linear edge of the member.

Claim 50

The valving member of claim 45 wherein: the trailing faces of the ears are located along a line, said line being located generally a distance from the trailing edge that is twice the distance between the line and the midportion of the leading edge.

Claim 51

The valving member of claim 44 wherein: each ear has an outwardly inclined ramp extended toward the trailing edge of the member.

Claim 52

A heart valve prosthesis comprising: a base having an inside annular wall surrounding a passage for carrying blood through the base, means for connecting the base to heart tissue, said means including first means and second means for connecting the first means to heart tissue, and coacting means on the base and first means operable to permit removal of the base from the first means after the first means is connected to heart tissue, valving means for controlling the flow of blood through the passage, said valving means comprising a first valving member and a second valving member, first pivot means pivotally mounting the first valving member on the base, second pivot means pivotally mounting the second valving member on the base, and side members on the base projected in the direction of flow of blood through the passage, said side members having stop means engageable with the first and second valving members when said first and second valving members are in their closed positions.

Claim 53

A heart valve prosthesis comprising: a base having an inside annular wall surrounding a passage for carrying blood through the base, means for connecting the base to heart tissue, said means including first means and second means for connecting the first means to heart tissue, and coacting means on the base and first means operable to permit removal of the base from the first means after the first means is connected to heart tissue, valving means for controlling the flow of blood through the passage, said valving means comprising a first valving member and a second valving member, first pivot means pivotally mounting the first valving member on the base, second pivot means pivotally mounting the second valving member on the base, and side members on the base projected in the direction of flow of blood through the passage, said side members having stop means engageable with the first and second valving members when said first and second valving members are in their closed positions.

Claim 54

The prosthesis of claim 48 wherein: the first valving member and second valving member are inclined toward each other when in their closed positions.

Claim 55

The prosthesis of claim 49 wherein: the inclination is about 45° from the transverse plane of the passage.

Claim 56

The prosthesis of claim 48 wherein: the stop means includes a pair of side projections located on opposite sides of the base, each projection having portions that are engaged by the members when the members are in their closed positions.

Claim 57

The prosthesis of claim 48 wherein: the stop means comprise inclined and converging lip portions providing seats engageable with parts of the valving members when the valving members are in their closed positions.

Claim 58

The prosthesis of claim 48 including: second stop means comprising projections extended from the base engageable with parts of the valving members when the valving members are in their open positions.

Claim 59

The prosthesis of claim 48 wherein: each side member has a generally triangular shape.

Claim 60

The prosthesis of claim 48 wherein: each valving member has a leading edge having a thickness about twice the thickness of the trailing edge, and generally flat side surfaces between the leading and trailing edges.

Claim 61

The prosthesis of claim 47 wherein: each valving member is substantially balanced on its respective pivot means.

Claim 62

The prosthesis of claim 48 wherein: each valving member has outer peripheral edges spaced from the inside wall to allow limited reverse flow of blood between the valving members and the base when the valving members are in the closed positions.

Claim 63

The prosthesis of claim 48 wherein: the means for connecting the base to heart tissue includes a sleeve, and coacting means on the base and sleeve allowing the base to be removed from the sleeve after the means is connected to the heart tissue.

Claim 64

The prosthesis of claim 48 wherein: the first valving member pivots about a first axis offset from the center of the passage and the second valving member pivots about a second axis offset from the center of the .[.axis.]. .Iadd.passage.Iaddend., said first and second axes being located on opposite sides of the center of the passage and extended generally parallel to each other.

Claim 65

The prosthesis of claim 59 wherein: the side members are located between the first axis and the second axis.

Claim 66

A heart valve prosthesis comprising: a base having a pair of semi-circular segments located in a circular arrangement, said segments having an inside annular wall forming a passage through the base, annular means surrounding the segments for holding the segments in the circular arrangement, valving means movable to open and closed positions for controlling the flow of blood through said passage, and means secured to the segments cooperating with the valving means to hold the valving means in assembled relation with the base and controlling the opening and closing movements of the valving means.

Claim 67

A heart valve prosthesis comprising: a base having a pair of semi-circular segments located in a circular arrangement, said segments having an inside annular wall forming a passage through the base, annular means surrounding the segments for holding the segments in the circular arrangement, valving means movable to open and closed positions for controlling the flow of blood through said passage, and means secured to the segments cooperating with the valving means to hold the valving means in assembled relation with the base and controlling the opening and closing movements of the valving means.

Claim 68

The prosthesis of claim 61 wherein: the annular means is a circular sleeve having a plurality of holes, and said segments are provided with projections which extend into the holes.

Claim 69

The prosthesis of claim 62 wherein: the valving means includes two valving members and the means secured to the segments are pairs of pivot members cooperating with the valving members to hold the valving member on the base.

Claim 70

The prosthesis of claim 62 wherein: each segment has two pairs of pivot members, one pair cooperating with one valving member and the other pair cooperating with the second valving member whereby each valving member is controlled by two pairs of pivot members. .Iadd. 65. A heart valve prosthesis comprising: a base having an inside annular wall surrounding a passage for carrying blood through the base, means for connecting the base to heart tissue, valving means located in the passage operable to allow substantially unrestricted flow of blood in a first direction through the passage and to restrict the flow of blood in a second direction through the passage, said second direction being opposite the first direction, said valving means comprising a first valving member having a convex curved edge and a transverse edge, and a second valving member having a convex curved edge and a transverse edge, said first and second valving members when in their closed positions being obliquely inclined in opposite directions with respect to the longitudinal axis of the passage through the base, and said transverse edges being located adjacent each other, each valving member having an outer periphery having portions thereof spaced from the inside annular wall to allow limited flow of blood in the second direction between the valving members and the inside annular wall when the valving members are in their closed positions, first ear means on the first valving member, first pivot means pivotally connecting the first valving member to the base for movement about a first axis offset in one direction from the center of the passage, said first pivot means including said first ear means and first fulcrum portions on the base, said first ear means being engageable with the first fulcrum portions for controlling the movement of the first valving member between its open and closed positions, second ear means on the second valving member, and second pivot means pivotally connecting the second valving member to the base for movement about a second axis offset in a direction opposite the one direction from the center of the passage, said second pivot means including said second ear means and second fulcrum portions on the base, said second ear means being engageable with the second fulcrum portions for controlling the movement of the second valving member between its open and closed positions, said first and second axes being generally parallel to each other, said base including a first side member and a second side member, said first and second side members forming barriers adjacent opposite sides of the first and second valving members when the valving members are in their closed positions to minimize the flow of blood through the passage in the second direction, first stop means engageable with the first valving member and second valving member to hold the first valving member and second valving member in their closed positions to restrict the flow of blood in the second direction through the passage, and second stop means engageable with the first valving member and second valving member when the valving members are in their open positions to allow substantially free flow of blood through the passage in the first direction. .Iaddend..Iadd. 66. The prosthesis of claim 65 wherein: each side member has an inside surface coextensive with the inside annular wall. .Iaddend..Iadd. 67. The prosthesis of claim 65 wherein: each valving member has opposite side portions, said first ear means being secured to the opposite side portions of the first valving member, and said second ear means being secured to the opposite side portion of the second valving member. .Iaddend..Iadd. 68. The prosthesis of claim 65 wherein: each side member includes converging side edges. .Iaddend..Iadd. 69. The prosthesis of claim 68 wherein: each side member has a convex curved outer surface. .Iaddend. .Iadd. 70. A heart valve prosthesis comprising: base means having an inside annular wall surrounding a passage for carrying blood through the base means, a first side member, and a second side member opposite the first side member, valve means located in the passage operable to allow substantially unrestricted flow of blood in a first direction through the passage and to restrict the flow of blood in a second direction through the passage, said second direction being opposite the first direction, said valve means comprising a first valving member having a convex curved edge, opposite side edges, a transverse edge, and first ear means adjacent the opposite side edges, and a second valving member having a convex curved edge, opposite side edges, a transverse edge, and a second ear means adjacent the opposite side edges of the second valving member, first pivot means pivotally associating the first valving member with the base means, said first pivot means including the first ear means and fulcrum portions of the base means, said first ear means being engageable with the fulcrum portions for controlling the movement of the first valve member in a location offset in one direction from the center of the passage, second pivot means pivotally associating the second valving member with the base means, said second pivot means including the second ear means and fulcrum portions on the base means, said second ear means being engageable with the fulcrum portion of the second pivot means for controlling the movement of the second valving means in a location offset in a second direction opposite the first direction from the center of the base, said first and second valving members concurrently pivoting between open and closed positions to control the flow of blood through the passage of the base means, said first and second valving members when in their closed positions being inclined in opposite directions with respect to the longitudinal axis of the passage, and said transverse edges of the first and second valving members being located adjacent each other, said base means having first stop means engageable with the first valving member and the second valving member to limit pivotal movement of the first valving member and second valving member to their opposite inclined closed positions to restrict the flow of blood in the second direction through the passage, and second stop means on the base means engageable with the first valving member and second valving member to limit pivotal movement of the first and second valving members to open positions. .Iaddend..Iadd. 71. The prosthesis of claim 70 wherein: each side member has an inside surface coextensive with the inside annular wall. .Iaddend..Iadd. 72. The prosthesis of claim 70 wherein: the transverse edges of the first and second valving members are spaced apart when the valving members are in their closed positions. .Iaddend..Iadd. 73. The prosthesis of claim 70 wherein: each valving member has an outer peripheral edge spaced from the inside wall to allow limited flow of blood in the second direction between the valving members and the inside annular wall when the first and second valving members are in their closed positions. .Iaddend..Iadd. 74. The prosthesis of claim 70 wherein: said first stop means includes a first stop face engageable with the first valving member and a second stop face engageable with the second valving member when the first and second valving members are in their closed positions. .Iaddend. .Iadd. 75. The prosthesis of claim 70 wherein: said second stop means includes a first stop face engageable with the first valving member and a second stop face engageable with the second valving member when the first and second valving members are in their open positions. .Iaddend..Iadd. 76. The prosthesis of claim 70 including: means on the base means for connecting the base means to heart tissue. .Iaddend..Iadd. 77. A heart valve prosthesis comprising: a base having an inside annular wall surrounding a passage for carrying blood through the base, said passage having a longitudinal central axis, said base including a first side member projected generally parallel to the longitudinal axis of the passage, and a second side member opposite the first side member projected generally parallel to the longitudinal axis of the passage, means mounted on the base for connecting the base to heart tissue, valving means located in the passage operable to allow substantially unrestricted flow of blood in a first direction through the passage and to restrict the flow of blood in a second direction through the passage, said second direction being opposite the first direction, said valving means comprising a first valving member having a convex curved edge, a transverse edge, and first ears, a second valving member having a convex curved edge, a transverse edge, and second ears, first pivot means pivotally associating the first valving member with the base for movement about a first axis offset in one direction from the center of the passage, said first pivot means including said first ears and first fulcrum portions on the base, said first ears being engageable with the first fulcrum portions for controlling the movement of the first valving member between its open and closed positions, second pivot means pivotally associating the second valving member with the base for movement about a second axis offset in a direction opposite the one direction from the center of the passage, said second pivot means including said second ears and second fulcrum portions on the base, said second ears being engageable with the second fulcrum portions for controlling the movement of the second valving member between its open and closed positions, said first and second valving members concurrently pivoting between open and closed positions to control the flow of blood through the passage of the base, said first and second valving members when in their closed positions being obliquely inclined in opposite directions with respect to the longitudinal axis of the passage, and said transverse edges of the first and second valving members being located adjacent each other, said base having first stop means engageable with the first valving member and the second valving member to limit pivotal movement of the first valving member and the second valving member to opposite obliquely inclined closed positions to restrict the flow of blood in the second direction through the passage, said base further including second stop means engageable with the first valving member and second valving member to limit pivotal movement of the first and second valving members to open positions. .Iaddend..Iadd. 78. The prosthesis of claim 77 wherein: each side member has an inside surface coextensive with the inside annular wall. .Iaddend..Iadd. 79. The prosthesis of claim 77 wherein: each valving member has an outer peripheral edge spaced from the inside annular wall to allow limited flow of blood in the second direction between the valving members and the inside annular wall of the base when the valving members are in their closed positions. .Iaddend.g 80. The prosthesis of claim 77 wherein: each valving member has opposite side portions, said first ears being secured to opposite side portions of the first valving member, said second ears being secured to opposite side portions of the second valving member. .Iadd. 81. The prosthesis of claim 77 wherein: said first stop means includes a first stop face engageable with the first valving member and second stop face engageable with the second valving member when the first and second valving members are in their closed positions. .Iaddend..Iadd. 82. The prosthesis of claim 77 wherein: the second stop means includes a first stop face engageable with the first valving member and a second stop face engageable with the second valving member when the valving members are in their open positions. .Iaddend.