Aorta valve with expansible suturing ring

Aug. 2, 1966

M. L· EDWARDS ETAL 3,263,239

AORTA VALVE WITH EXPANSIBLE SUTURING RING

Filed April 1, 1963

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United States Patent Office _{Palented Aeg}j_{t 2},₁₉₆₆ indicated by the angle at 16. In order to prevent any possibility of the ball escaping through the port, special retention means may be provided. These comprise three inwardly and downwardly directed stop fingers .17. Pref5 erably, these stops are disposed between the three legs of cage 12. The stops may be omitted when the dimensions and angular relationships are such as to prevent the ball from escaping through the port in use. The resilient ball is inserted in the cage by squeezing it between two of the 10 cage legs.

The outside of base ring 11 forms an annular channel 20 having a nearly horizontal bottom wall 21 having a slight downward inclination and an upwardly inclined lop wall 22. In the illustrated embodiment the inclination of 15 wall 22 is approximately 45°. A flexible sewing ring 25 is mounted and secured in channel 20.

Sewing ring 25 preferably comprises a piece of knitted Teflon cloth having a mid-portion clamped in the channel 20 by a one-piece split spreader ring 26 of suitable ma20 tcrial such as Teflon plastic. The spreader ring 26 is itself channel-shaped in cross section with an external shape corresponding generally to the shape of channel 20 and having an outwardly facing channel 27. The spreader ring is clamped against at least one thickness of the cloth 25 by a winding 28 of Teflon thread which is wound under tension in chancl 27. When the body member 10 is made of metal, all the other parts should be non-metallic to prevent electrolysis.

The lower end portion 30 of the cloth is folded back on 30 upper portion 32 and stitched with Teflon thread 31 to a folded back upper end portion 33 of the cloth as shown. This produces a bight portion at 35 which encloses a resilient silicone rubber ring 36. The cloth is formed into a smoth frusto-conical shape by a pressing operation. ³³ This results in a sleeve of inverted flaring skirt shape which makes an angle of about 22° with the vertical as indicated by the angle 40. Rubber ring 36 serves as an extensile element to stiffen the free upper end of the skirt and hold it extended in circular configuration in plan view. The ⁴⁰ folded end portions at 30 and 33 abut each other to form a pad having a thickness of at least three layers of cloth. This provides secure anchorage for the sutures. Rubber ring 36 is not necessary in small sizes of the valve as then the cloth will hold itself in conical shape without a sep⁴⁵ aratc extensile element.

FIGURE 4 shows the manner of installing the valve in a human heart 45. The heart has a left atrium 46, a left ventricle 47, a right atrium 48 and a right ventricle 49. A mitral valve 50 prevents reverse flow of blood from left ° ventricle 47 back into left atrium 46 and a mitral valve 51 prevents reverse flow from right ventricle 49 back into right atrium 48. Blood flows from left ventricle 47 through an aorta valve into aorta 56 from whence it is ₅₅ distributed into main arteries 57 and others leading to different parts of the body. The aorta normally makes a sharp bend between the heart and the arteries 57, as shown.

The present valve is usually installed by making an incision 52 through the outside of this bend which pro60 vides access for surgical treatment of the natural aorta valve. The natural aorta valve parts are removed and the present valve is installed in the same location. The sewing ring 25 is secured to living tissue at the entrance to the aorta by threads or sutures 53 with the cage 12 cx⁰³ tending up into the aorta. The suturing is facilitated by the action of extensile rubber ring 36 which holds the tipper free end of the skirt portion of the sewing ring expanded into contact with the inside of the aorta wall, as _? shown. Normally, the aorta increases in size at this point whereby the flare of the skirt of the sewing ring conforms generally, with the taper of the aorta.

3.263,239 AORTA VALVE WITH EXPANSIBLE SUTURING RING

Miles Lowell Edwards, Santa Ana, Calif., and Albert Starr, Portland, Oreg., assignors to Edwards Laboratories, Inc., ° Santa Ana, Calif., a corporation of California

Filed Apr. 1, 1963, Ser. No. 269,299

Claims. (Cl. 3—1)

This application is a continuation-in-part of co-pcnding _]0application Serial No. 49,044 filed August 11, 1960, now Patent No. 3,099,016.

This invention relates to an artificial valve as a prothesis in a heart to take the place of a defective natural valve.

The valve illustrated in said prior patent is a mitral 15 valve, although the general features of construction therein disclosed arc applicable to both mitral and aorta valves. The present application is directed to certain modifications of structure in order to adapt the general principles of the prior invention for utilization in an aorta valve. The pres- 20 ent invention is not limited to aorta valves, however.

An aorta valve requires special consideration in its design and construction because the valve body must project into the aorta itself. There is less space for such mechanism in the aorta than in the chamber of the left ventricle 25 which contains the body of the mitral valve. Thus, although the aorta valve must handle the same quantity of blood as the mitral valve, it must be smaller in its outside dimensions whereby special provision must be made to avoid throttling the flow of blood. 30

The objects of the invention are, therefore, to provide an improved artificial valve, to provide an improved aorta valve, to provide a valve for implantation directly in the entrance to the aorta below the coronary arteries and to provide a sewing ring for an aorta valve of conical skirt 35 shape and made of expansile material which can change in diameter as variations in the blood pressure expand and. contract the diameter of the aorta.

The present valve is generally similar to the mitral valve mentioned above but incorporates certain special features ⁴ ’ to increase the size of the port opening relative to the size of the valve body and to facilitate attachment of the sewing ring to the heart tissue directly at the entrance to the aorta. Other features and advantages will become apparent from the following detailed description of the preferred ⁴⁰embodiment illustrated on the accompanying drawing. All variations and modifications within the scope of the appended claims are included in the invention.

In the drawing: _fi0

FIGURE 1 is a longitudinal sectional view of a valve embodying the principles of the invention;

FIGURE 2 is a top plan view of the valve in reduced scale with parts broken away;

FIGURE 3 is a bottom plan view of the valve; and _ββFIGURE 4 is a section of a human heart, showing the present valve installed therein.

The valve comprises an integral body member 10 made of a suitable material which is compatible with the human body. Various types of non-toxic plastic may be used, _βθ such as Dupont Lucite acrylic resin, Rohm &amp; Haas Plexiglas acrylic plastic, and the like. Metal is preferable to plastic, however, the preferred material being an alloy known as Stellite which is non-corrodiblc and inert to blood and living tissue. Stainless steel may also be used. _ββ

The entire body 10 comprising a base or port ring portion 11 and a cage portion 12 is preferably made in one piece cither as a molding or a casting. The base ring defines a valve port having nn internal spherical seat 13 corresponding to the curvature of silicone rubber ball IS. ₇₀In order to provide as large a port as possible, the maximum inclination of scat &lt;13 from the vertical is 15 as

3,263,230

The combination of upwardly inclined wall 22, the top surface of which conforms to the flow pattern of the blood, and the spacing of stop fingers 17 staggered between cage legs 12 provide maximum flow around the legs 12. This minimizes the tendency toward a shadow in the flow pattern between the legs and the sewing ring where clots could form. Usually about.two-thirds of the sutures may lie tied against the inner surface of the conical sewing ring adjacent to the legs of the cage. These suture knots arc inclined to excite the clot formation. The staggered arrangement of stop fingers and cage legs is to avoid a concentration of impediments in the flow through the valve. This provide maximum washing of blood around the cage legs to the area directly between the leg and the inside of the sewing skirt to minimize the possibility of clot formation at that area.

It is to be noted that the valve is installed below the coronary arteries 55 so that it functions in the circulatory system the same as the natural aorta valve.

A most important feature of the valve is the expansile sewing ring brought about by the nature of the cloth used and the rubber ring placed in the upper extremity of the skirt. It aids the surgeon in selection of a valve. Although measuring devices are used, they arc not precise and a certain amount of flexibility here is important.

Another point is that the valve is installed when the aorta is at zero pressure. When in use, the pressure extends the aorta diameter and the sewing ring must expand accordingly.

There is also the important point that the rubber ring being placed at the upper extremity of the skirt causes the pressure difference across the valve, when the valve is in a closed position, to be sealed at the location of the rubber ring forcing the entire area of the skirt outward against the aorta wall, preventing wrinkles. This action is very much like the seal in the leather cup of a bicycle tire pump.