US3374489A - Artificial heart valve - Google Patents

Description

March 26, 1968 F. R. ALVAREZ DIAZ 7 3,374,489

ARTIFICIAL HEART VALVE Filed March 26, 1965 INVMOR FRANCISCO RIPERTO ALVAREZ DMZ MJA' ATTORNEYS United States Patent 3,374,489 ARTIFICIAL HEART VALVE Francisco R. Alvarez Diaz, Antonio Arias 12, Madrid, Spain Filed Mar. 26, 1965, Ser. No. 442,897 Claims priority, application Spain, Apr. 7, 1964, 298,382 12 Claims. (Cl. 3--1) ABSTRACT OF THE DISCLOSURE An artificial mitral valve for intracardiac implantation includes a ring constituting a valve seat having an outer portion for suturing in position, and a disc-shaped valve member loosely connected with said ring to oscillate between open and closed positions.

BACKGROUND OF THE INVENTION The only effective treatment for numerous sufferers from mitral insufiiciently or calcified mitral stenosis, comprises the implantation of an artificial mitral valve, without which such sufferers will die within a relatively short period of time. The ideal type of artificial mitral valve would necessarily have certain definite character: istics, namely: it would be absolutely eflicient; it would not cause stenosis, but would permit sufiicient free flow of blood to the ventricle, namely at least 15 litres per minute and equal to the volume delivered by the left ventricle under semiforced working conditions; articulation of the valve should be by a simple, free and safe mechanism avoiding thrombosis; it should not protrude more than 1.5 centimetres into the left ventricle; it should not produce heamolysis; there should be no dead spaces that would cause thrombosis; it should incorporate a safe fastening mechanism, and it should be constructed of inert, perfectly tolerated material.

With the object of devising the artificial mitral valve which will comply with all these conditions, intensive work is being carried out at various centers. In this way, various models have been produced, each of which endeavors to overcome one of the disadvantages of previous designs, but up to the present time the ideal construction has not been found. In the last four years, numerous valvular prostheses have been reported, but none of these have been adequate to be regarded as the definitive solution.

In the year 1960, a valve appeared but it has the following disadvantages: it is situated entirely in the left ventricle, so that it interferes with the tract running from the ventricle to the aorta, in many cases making contact with the wall of said tract and thus causing subendocardial hematomas, giving rise to arrhythmias and sometimes to ventricular fibrillation and the death of the patient. Blood does not pass rapidly and freely to the ventricle, and on occasion the heaemolyses produced are considerable through the friction of the blood through the box.

In an attempt to overcome these disadvantages in the year 1962, another valve was produced but it has the disadvantage that it causes rapid and intense thrombosis because the support of a central rod is fixed, so that patients have to spend their entire life under anticoagulant medication with the consequent risk of hemorrhage.

In the year 1963, still another mitral valve was produced, having certain advantages over previous designs, but has the great disadvantage that it has the effect of producing stenosis since the passage of blood is not free.

All other valvular prostheses reported have even greater disadvantages, and at the present time most of this work has been abandoned. Of the three valves referred to above, the first mentioned valve is at the present time used almost throughout the world, despite its serious disadvantages, because other valves, which have the same disadvantages, have not been successful.

SUMMARY OF THE INVENTION Briefly, an artificial mitral valve for intracardiac implanation, according to the invention, includes a ring constituting a valve seat having an outer portion for suturing in position, and has a pair of inward projections, and a biconvex disc-shaped valve member having a pair of columns extending from one face thereof through said ring respectively adjacent said projections, said columns terminating in angled end portions loosely overlying the opposite side of said ring from said valve member and permitting the latter to oscillate between open and closed positions.

The structure is formed of inert material that is perfectly tolerated by the patients heart upon implantation, is absolutely efficient and safe and has no deleterious effects, is easily implanted and has a simple and safe mounting and has a simple articulation mechanism capable of constant movement and free of dead spaces,

BRIEF DESCRIPTION OF DRAWING The novel features that are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawing, wherein like reference characters indicate like parts throughout the several figures and in which:

FIG. 1 is a plan view of a support ring for an artificial mitral valve in accordance with the present invention;

FIG. 2 is a cross-sectional view taken on line 22 of FIG. 1;

FIG. 3 is an enlarged fragmentary plan view of a portion of the ring and one of the mounting stops;

FIG. 3' is a cross-sectional view taken on line 33' of FIG. 3;

FIG. 4 is a plan view of the valve element for an artificial mitral valve in accordance with the invention;

FIG. 5 is a side view of the valve element shown in FIG. 4;

FIG. 5' is a side view of the valve element similar to that of FIG. 5, but oriented substantially 45 as in the DETAILED DESCRIPTION OF INVENTION Referring now to the drawing in detail, an artificial mitral valve according to the invention comprises two parts; a mounting ring 1, FIG. 1, and a flattened biconvex cushion-shaped valve element 8, FIG. 4, which is articulated on and supported by said ring 1, as shown in FIG. 6. The mounting ring 1 comprises a base ring 2 and the latter as well as thevalve element 8 are made of inert materials which are perfectly tolerated by the human body.

The ring 2, FIGS. l-3, is circular in shape with smooth flat sides that taper inwardly to aninner wall 3 having a diameter varying between one and three centimetres, while, depending on the diameter, its width varies between three and six millimetres. The outer periphery of said ring 2 is provided with a V-shaped channel formed by two rims 4, one at the top and the other at the bottom, both being oblique and converging towards the center of the Patented Mar. 26, 1968' ring. At their outer edges, the rims 4 are about six millimetres apart, and the width of the inner face of the rim is from one to four millimetres.

Protruding inwardly from theinner wall 3 of the ring 2 are two stops 7 of triangular shape, FIG. 3, situated one on each side of the ring at a distance of about two millimetre-s from a diametrical axis XX, FIG. 1. The channel in the outer periphery contains asecond ring 6 of a material capable of being pierced by a needle and of holding sutures for the fastening of the ring 1 in position, thissecond ring 6 being fixed in the channel by means of an embedded stainless steel wire 5. Thering 6 maybe in the form of a mesh or the like and of a mate- 1gial that is inert and is perfectly tolerated by the human ody.

Thevalve element 8 has a flattened biconvex body having a bottom or ventricular face 11, and an upper orauricular face 10. The ventricular face is of circular shape, smooth, with slight convexity; while the auricular face is likewise convex, with twocolumns 9 situated eccentricaliy on a line YY, FIG. 4, disposed perpendicularly one third along the length of the diameter Z-Z. These columns extend upwardly from the body adjacent the periphery thereof and have angularly disposedfree end portions 9 extending toward the body periphery.

Thecolumns 9 are slightly conical with their outside edges substantially perpendicular to the medial plane P-P of thebody 8, FIG. 5, and the axes B--B of the columns, FIG. are inclined outwardly at about 100115 relative to said plane, said columns being of greater width at their bases joined to the body. The outer free ends 9' of the columns extend at right angles to the inclined inner edges of the columns, and point outwards at an angle of about to the line YY, FIG. 4, passing through the axes of the columns.

Thevalve element 8 is articulated to the mounting ring 1 by means of thecolumns 9 which are disposed within the ring 1, and with theirfree ends 9 overlying one side of the ring. Thecolumns 9 are partially straddled by the stops 7, respectively, to prevent relative rotational movement. The height of the columns is slightly greater than the thickness of the ring 1 so that thevalve element 8 is capable of movement in the perpendicular direction of about four to eight millimetres, depending on size, and the eccentric disposition of the columns enables movementin the diagonal direction, as shown in FIG. 6, of one to two centimetres.

The circular shape of thecolumns 9 and the triangular configuration of the stops 7 precludes dead spaces that are unaffected by the oscillatory movement between these parts caused by the oscillation of thevalve element 8. Thus, the articulation mechanism is safe and simple in operation and capable of constant movement, thereby precluding thrombosis.

As previously stated, the valve parts are made of inert material that is perfectly tolerated -by the human body. Preferably, the carrier ring 1 andvalve element 8 are made of synthetic elastomers which have sufiicient rigidity to prevent undesired deformation, but have sufficient elasticity or resilience to enable insertion of the columns 7 9 within the ring 1. Suitable materials for these parts are polypropylene or Silastic (W. A. Cleary Corp., New Brunswick, N.J.). The outer oranchor ring 6 may be formed of Teflon or Dacron (E. I. du Pont de Nemours & Co., Inc., Wilmington, Del.) or Terylene (Imperial Chemical Industries Ltd., Imperial Chemical House, Milbank, London, England).

This valve is constructed in different sizes, namely with inside ring diameters of 1.75, 2.25, 2.50, 2.75 and 3 centimetres.

In use, the valve assembly is implanted surgically in place of a scarred and damaged mitral valve between the left auricle and the left ventricle. The damaged mitral valve is excised and the outer oranchor ring 6 is sutured within the opening from which the mitral valve has been excised. The valve is disposed on the ventricalside of the ring with the face 11 of thevalve element 8 toward the ventrical, and theface 10 toward the auricle. The ring 1 then constitutes the valve seat for thevalve element 8, and itsinner periphery 3 the valve passageway.

The mitral valve according to the present invention complies with all the conditions required for a rigid mitral valve, having great advantages and no disadvantage. In numerous experimental studies and in special valve testing apparatus (duplicator), it has been found that this valve is:

(1) Absolutely eflicient.

(2) It does not cause stenosis. It passes 30 litres per minute, so that the margin of reserve is 15 litres because, as has been indicated, the actual requirement is 15 litres per minute.

(3) Its articulation mechanism is safe and simple articulation and in constant movement.

(4) It does not cause haemolysis.

(5) It does not cause thrombosis (simple articulation mechanism in constant movement and without dead spaces).

(6) Its fastening mechanism is safe.

(7) The material used is inert and perfectly tolerated by the human body.

Although a certain specific embodiment of the invention has been shown and described, it is obvious that many modifications thereof are possible. The invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

What I claim is:

1. An artificial heart valve for intracardiac implantation comprising a carrier ring defining a valve passageway and a valve seat one one side of said ring, and a disc-shaped valve element having a diameter greater than that of said passageway and having one side engageable with said seat, two columns projecting from said one side of said valve element through said passageway and having end portions overlying the side of said ring opposite said seat to retain said element and ring in assembled relation, said columns having a length greater than the thickness of said ring to permit movement of said element relative to said ring, and said carrier ring having two projections extending inwardly into said passageway and respectively engaging said columns to steady said valve element in relation to said ring and to obstruct rotational displacement of said valve element relative to said ring but permitting free movement of said valve element toward and from said seat.

2. A heart valve according to claim 1 wherein said columns are eccentrically disposed relative to said one side of said valve element so that the movement thereof is oscillatory in both an axial and an angular direction.

3. An artificial heart valve for intracardiac implantation comprising a carrier ring defining a valve passageway and a valve seat on one side of said ring, and a discshaped valve element having a diameter greater than that of said passageway and engageable with said seat, 7

said valve element having members projecting therefrom through said passageway and overlying the side of said ring opposite said seat to retain said element and ring in assembled relation, said projecting members having a length greater than the thickness of said ring to permit movement of said element relative to said ring, said carrier ring having two projections extending inwardly into said passageway and respectively straddling said projecting members to steady said valve element in relation to said ring and to obstruct rotational displacement of said valve element relative to said ring but permitting free movement of said valve element toward and from said seat, said projecting members being L-shaped with the L-bends at the free ends thereof disposed to overlie said ring.

inv

4. A heart valve as claimed inclaim 3 wherein said carrier ring has a peripheral channel, and an outer ring of material adapted to be sutured in the opening from which the natural heart valve has been excised for implantation of the valve.

5. A heart valve as set forth in claim 4 wherein said outer ring is held in the channel of the carrier ring by a ring of stainless steel wire embedded in the outer ring.

6. A heart valve as set forth in claim 5 wherein the cross-section of the carrier ring is divergent from the inner to the outer diameter or" the ring.

7. A heart valve as set forth inclaim 6 wherein the valve element is of biconvex form, and said projecting members on one face comprise two eccentrically disposed upstanding columns inclined towards the respectively nearest edge of the valve element, each L-shaped bend on said columns being directed towards the periphery of the valve element.

8. A heart valve as set forth in claim 7 wherein said columns between said element and their bends are of a length greater than the thickness of said carrier ring, whereby the opening movement of the valve element is effected with a movement in an axial direction, and another larger movement in a diagonal direction, in the direction of the ventricle.

9. A heart valve as set forth inclaim 8 wherein said carrier ring, valve element and said outer ring are made of inert materials that are perfectly tolerated by the human body.

10. A heart valve as set forth inclaim 9 wherein said carrier ring and valve element are made of synthetic elastomers.

11. A heart valve as set forth inclaim 10 wherein said carrier ring and valve element are made of a material selected from the group consisting of polypropylene and Silastic.

12. A heart valve as set forth inclaim 9 wherein said outer ring is made of a material selected from the group consisting of Teflon and Dacron.

References Cited UNITED STATES PATENTS 2,877,792 3/1959 Tybus 137527 XR 3,099,016 7/1963 Edwards 31 3,113,586 12/1963 Edmark 3-1 XR 3,294,116 12/1966 Tremeau 137533 XR OTHER REFERENCES The Development of A Prosthetic Heart Valve Utilizing A Rigid Housing and a Fexible Butterfly Wing Leaflet by V. L. Gott et al., Transactions American Society for Artificial Internal Organs, vol. VIII, April 1962, pp. 72-78 (Group 335).

Evaluation of Two Prosthesis for Total Replacement of the Mitral Valve by F. S. Cross et. al., The Journal of Thoracic and Cardiovascular Surgery, vol. 46, No. 6, December 1963, pp. 7l9725.

Comparative Study of Some Prosthetic Valves for Aortic and Mitral Replacement by C. A. Hufnagel et. al., Surgery, vol. 57, No. 1, January 1965, pp. 205-210.

RICHARD A. GAUDET, Primary Examiner.

R. L. FRINKS, Assistant Examiner.

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