Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Heart valve – Having rigid or semirigid pivoting occluder
Patent
1990-07-12
1992-01-07
Shay, Randy C.
Prosthesis (i.e., artificial body members), parts thereof, or ai
Heart valve
Having rigid or semirigid pivoting occluder
A61F 224
Patent
active
050787381
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to an artificial cardiac valve.
Numerous artificial cardiac valves employing flap valve devices of the ball, disc or flap type in the form of a hemi-disc, already exist.
This is the case, for example, of the valves described in Patent Applications EP 0 176 337 (CARBOMEDICS INC.), EP 0 023 797 (HEMEX INC.), EP 0 039 217 (MITRAL MEDICAL INTERNATIONAL, INC. and EP 0 050 971 (HEMEX INC.).
Furthermore, GB 2 084 299 (HEMEX INC.) describes a cardiac valve comprising an annular element and a flap pivotally lodged inside said element as well as linking elements adapted to cooperate with guiding and restraining means provided on the internal lateral wall of the annular element.
These documents describe in particular valves of the type comprising a flap with single pivoting disc. The disc in question pivots by means of hinges in the form of protuberances disposed on the inner wall of the body of the valve and which, due to their configurations and arrangements, are capable of provoking phenomena of thrombosis.
Furthermore, these valves are in a position of complete opening only when the flap has pivoted through a certain angle which is always less than 90.degree. about an axis of rotation which merges with its diameter. In fact, the limited angle of 90.degree. does not allow passive closure of the valve. Consequently, in the position of opening, half of the disc constituting the flap is engaged in the aorta, which may raise problems of flow and/or space requirements.
Moreover, it is observed that these valves tend to oscillate due to the great distance between the axis of rotation and the most remote end of the flap.
SUMMARY OF THE INVENTION
The present invention enables these drawbacks to be overcome for the first time and in satisfactory manner, by proposing an artificial cardiac valve made of biocompatible material, of the type comprising:
an annular element of axis YY, a flap pivotally lodged inside said element and presenting linking elements adapted to cooperate with guiding and restraining means provided on the internal side wall of the annular element, characterized in that said flap is constituted by a disc folded along a line XX' parallel to one of its diameters so as to present a rear part and a front part located on either side of the line XX', the rear and front parts forming therebetween an angle greater than 150.degree., with the result that the opening of the valve is effected in two consecutive phases, the first phase corresponding to a rotation of the flap about the contact and hinging point A of the rear part of the flap with the lower edge of the side wall of said element until said linking elements abut in the guiding and restraining means, and the second phase corresponding to a rotation about an axis ZZ' parallel to axis XX' until the rear part of the flap is parallel to axis YY' of the element.
The cardiac valve of the invention is also characterized in that said guiding and restraining means are constituted by two symmetrical lateral slideways made in the mass of the element and in which the linking elements of the flap are movably engaged.
These slideways may be constituted by an arc of circle of centre A and of radius equal to the rear part of the flap, or by hollows comprising, over at least a part of their periphery, straight flanks forming stops.
The linking elements are provided laterally and symmetrically on axis ZZ' of the flap and are preferably constituted by two pivots or two ears.
The cardiac valve of the invention therefore presents in position of opening a so-called rear part parallel to the axis of the element, which is not produced with the disc valves of the prior art.
On the other hand, the two orifices existing during opening between the flap and the inner wall of the element and constituting the passageways for the flow of blood are of substantially equal dimensions.
In addition, the lateral internal wall of the element of the valve presents no obstructions for impeding the flow of blood, thus reducing the risks
REFERENCES:
patent: 4328592 (1982-05-01), Klawitter
patent: 4443894 (1984-04-01), Klawitter
E.R.A.C.C. Etudes, Recherches et Applications en Chirurgie Cardi
Shay Randy C.
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