Heart valve prosthesis

The invention relates to a heart valve prosthesis with a fixed, uniform, animal aortic valve according to the preamble of claim 1.

From US-A-35 70 014 a prosthetic heart valve with a metal carrier is known, with the heart valve of animal origin is sewn. The substantially cylindrical metal support has three axially extending posts, in which are provided, as well as in the annular region of the base recesses.

From WO-A-82/02829 it is known to use the biological material of feral pigs for the production of prosthetic heart valves and to remove the muscular fibers of the "septal cuspae".

The prosthetic heart valve replacement with biological tissue valves showing in terms of Tromboembolierate, postoperative morbidity and quality of life, good results and is now the world an accepted treatment. Experience with porcine tissue valves are since 1970th The shorter durability of these prostheses compared to mechanical valves, premature calcification in young patients and the high transvalvular pressure gradient at the small flap sizes, however, have often led to complications and reoperations. The latter is due to the rigid approach of the right Aortentaschenklappe that several millimeters sits the muscular ventricular septum porcine heart. After collection and preparation of the flap adhering muscle remnants are rigid fixation process with glutaraldehyde, thus preventing the free movement of the right pocket flap.

To address this problem, new methods are always been developed (shortening of the carrier cylinder height, modified fixing, low-pressure fixation), which led to a modification of porcine bioprosthesis.

However, these modifications mean in the production of prostheses significantly more work on engineering and manufacturing, which is associated with price increases.

The invention is based on the recognition that the right pocket flap seen several millimeters is adherent to the Muskelwulst of Ventrikelspektrums in porcine xenografts previously used at the base of her neck at the annulus fibrosis of. To eliminate this disadvantage by trying emanating from the annulus fibrosis dissection of the right pocket flap, the free movement of the pocket flap interfering muscle mechanically to remove eg by scraping. Apart from as the related high production costs, the troublesome muscle tissue but can not be completely removed, so that in the subsequent fixing process with a 2% glutaraldehyde solution, the muscular proportions are rigid and thus the bag mobility from the edge hamper starting. Therefore, a so formed prosthetic heart valve during the opening cycle not rise far enough what an undesirably high hemodynamic pressure gradient due.

It has now tried to use larger porcine aortic valves in order to have sufficient material to enable can be taken out, the overgrown with muscle tissue of the right pocket flap of the aortic lumen and wrapped around the bottom of the carrier. In such prostheses, the tissue of the right pocket flap is pulled around the vehicle to the outside, which often result in long-term exposure to tissue rupture with blood inflow and subsequent calcification of the sensitive kink.

Finally, you have already tried to assemble prosthetic heart valves from individual pocket flaps, but this can be apart from the extraordinary production effort expect a shorter life because the many seams be weakened.

The aim of the invention is thus to provide a prosthetic heart valve of the aforementioned type, in which the mobility, in particular the right pocket flap of the mobility of a human heart valve as close as possible without the Spring pocket flap from a at the bottom of the fabric firmly sewn annulus fibrosus must be dispensed with and without pocket flaps have to be pieced together from various aortic valves.

To achieve this object, the invention provides the characterizing features of claim 1.

The invention is thus based on the insight that for a killed by the fixing process aortic valve, it is important that it springs from a fixed to the Dacron fabric in an area of ​​the lower edge of the support frame annulus fibrosis and not or only in a mobility scarcely debilitating extent is adherent to the muscle tissue of the ventricular septum. This condition meets the aortic valve of a preferably male red and gray giant kangaroos of the genus Macropus giganteus and Macropus rufus in an ideal manner.

To prepare the aortic valve, the aortic root are cut with communal myocardium and several centimeters long aortic stump from pre-fixed heart.

The advantage of using fixed kangaroo aortic valve is particularly due to the fact that the aortic wall with their elastic fibers and smooth muscle along the sine valsalvae goes up to the projecting Muskelwulst. Only then begins a very flat small annulus fibrosis, which is anchored with individual small collagen fiber fingers in Septummuskulatur. The right pocket flap springs so without overlie the Muskelwulst, almost free from the annulus fibrosis in the aortic lumen.

Thus, the invention provides a heart valve prosthesis, wherein said approach the right pocket flap is shorter along with a much smaller annulus fibrosus in relation to the overall diameter of the aortic orifice than is the case with porcine xenografts. This reduces the immobile after the setting process portion of the right pocket flap, which leads to a significant enlargement of the valve area during the opening cycle compared to porcine xenografts. When using the valve according to the invention as a xenograft ie occur less pressure jumps than with porcine tissue valves. So can just be achieved with small flap sizes a significant functional improvement. Kangaroo aortic valves can be manufactured in sizes 17 to 31 mm. They can be employed as a valve replacement in all four positions of the heart, so use eg as aortic or mitral valve.

The support frame preferably consists of a very thermally stable plastic, for example an acetyl copolymer resin (Delrin®). In the carrier be coated fabric is generally a double-knit polyester manufacturer.

To make the benefits of a fixed kangaroo aortic valve and in particular their effective aperture ratio fully effective, the support frame in a particularly advantageous manner is 2 to 11 formed by one or more of the claims. The most preferred sizing figures relate to a uncoiled in a plane support frame (Fig. 3a).

The width of the budget for the placement of the commissure posts in the invention is about 1/4 of the outer diameter of the support frame; the equidistant commissure posts are so inventively designed so wide that about a 30 ° -Tolerance may be present in the arrangement of the commissures. With kangaroo aortic valve arrangement of the commissure varies in contrast only by an angle of about 15 °.

According to an advantageous embodiment of the invention is further provided that the carrier frame relative to the support frame used previously for porcine valves has significantly shorter commissure posts. Also, the overall profile is axially lower.

The remote from the post entrance edge is so weak wave-shaped, that on it a flat mitral suture ring can be attached as well as an arc-shaped aortic suture ring. Particularly advantageously, the prosthesis of the invention can also be integrated into a vascular prosthesis with integrated heart valve.

Particularly important are the numerous holes, holes and slots in the support frame, which are practically provided in all areas of the support frame, so that not only the elastic properties of the support frame are substantially improved, but also many fastening possibilities for the present in the form of a tube, the support frame sides covering Dacron Gewebe® exist.

The width of the annular region is chosen so that a maximum space for a free movement of the pouch flap is present.

The invention is described in the following example with reference to the drawing; shows in this<dl id="dl0001"><dt>Fig. 1</dt><dd>a side view of a prosthetic heart valve according to the invention at a scale of 3: 1,</dd><dt>FIG. 2</dt><dd>a view of the object of FIG. 1 from below, but turned through 180 ° about the central axis,</dd><dt>Fig. 3</dt><dd>a side view of the support frame used in the prosthetic heart valve according to FIGS. 1 and 2,</dd><dt>Fig. 3a</dt><dd>A settlement of the support frame of FIG. 3 to the drawing plane and</dd><dt>Fig. 4</dt><dd>a view of the carrier frame of FIG. 3 from below.</dd></dl>

According to FIGS. 1 and 2, an inside and outside with a polyester, such as Dacron® fabric 23 coated carrier frame 22 (Fig. 3, 4) from a acetyl, for example, Delrin® a substantially circular cylindrical shape. At the bottom in Fig. 1 edge 11 of the tissue 23 is formed by folding formation into a suture ring 14 in which a lower edge 11 of the support frame 22 surrounding elastic supporting ring can be accommodated. The suture ring 14 is used to sew the heart valve prosthesis to the human tissue, for example the aorta. FIGS. 3, 3a and 4, the support frame 22 consists of a wound to a circular cylinder form the band-shaped material, whose thickness is approximately 1/40 of the outer diameter of the support frame 22.

As is particularly evident from FIG. 3 and whose plane processing according to Fig. 3a, has the band-shaped material has a slightly wavy curved ring portion 13 with three full, each having a crest and a trough having waves, wherein the region of each wave crest a post 12 axially extends in the direction of the later opening pocket flaps.

be located axially extending slots 19, which have the shape of two connected half circles by straight lines whose radius is 0.064 times the outer diameter of the support frame 22 in each post 12th The distance between the two center points of the semicircles is 1/10 of the outer diameter of the support frame 22nd

In the region of their vertex 28, the posts 12 are rounded corresponding to the upper semi-circle of the slots 19, so that 12 material remains between the elongated holes 19 and the upper boundary of the post with a width which is equal to 1/16 of the outer diameter of the support frame 22nd

Between two adjacent posts 12 of the annular region 13 is bounded at the top by an upper edge 24, having the shape of a concave circular arc with its center of curvature 27 in the middle of the connecting line 30 between the apices 28 of adjacent posts 12th The upper edge 24 thus has in the aftermath of Fig. 3a approximately semicircular shape and goes through a reversal point 33 in the apex 28 having the area of ​​post 12 about.

On the axially facing away from the apex 28 side of the elongated hole 19 is located in the annular region 13 is a circular hole 20 whose diameter is a factor of 0.093 smaller than the outer diameter of the support frame 22nd The hole 20 is located in the middle between the slot 19 and the bottom 11 of the annular region. 13

The lower edge 11 of the carrier frame 22, 12 is concave circular curved in the region of the posts, wherein the center of curvature 29 19 lies on the center axis 34 of the elongated hole at a significant distance from the connecting line 31 between adjacent crests 32 of the wave-shaped lower edge 11, on the side facing away from the post 12 side of the connection line 31. Preferably the distance between the center of curvature 29 of the connection line 31 is about equal to half the outside diameter of the support frame 22. the radius of the circular arc about the center of curvature 29 to about 50% larger than the radius of the circular arc around the top center of curvature 27 and is advantageously from 0.6 times of the outer diameter of the support frame 22. the centers of curvature 27 and 29 are offset in the circumferential direction by an angle of 60 ° to each other. Also, the apex 28 and 32 are offset in the circumferential direction by an angle of 60 ° to each other. The circular arc-shaped part of the lower edge 11 with the center of curvature 29 is about the turning points 37 in the region of the apex 32 lying circular convex curved parts with approximately the same radius of curvature as the area with the center of curvature 29 above.

In the middle of the band-shaped ring region 13 is located at that circumferential position where the apex 32 are provided, each having a circular bore 25 with a diameter which is about a factor 0,064 less than the outer diameter of the support frame 22nd

On both sides of said bore 25 joins with a small distance approximately equal to the diameter of the bore 25 a respective longitudinal slot 26, which is curved according to the circular concave part of the upper edge 24 and extends parallel to this part of the upper edge fourteenth The longitudinal slots 26 extend approximately up to the beginning of the post 12 and terminate at a distance from the elongated holes 19 and the hole 20 which corresponds approximately to the width of the elongated holes 19th In the region of the apex 32, the edges 24 extend 11, substantially parallel to each other.

Due to the invention, only slightly wavy shape of the ring portion 13 and the axially relatively short post 12 and the enforcement of the invention the support frame 22 with holes, holes and slots, the support frame is after attaching the Dacron® fabric 23 as shown in FIGS. 1 and 2 optimally for attaching a kangaroo aortic valve with the mind still under aortic stump 40. Within this support frame 22, the pocket flaps 15, 16, 17 (Fig. 1 and 2) can move properly in the full open position and close freely again. The support frame 22 also includes a result of the inventive construction of an excellent elastic behavior, which substantially corresponds to the elastic behavior of the aorta or of the heart portion in which the artificial heart is implanted. Thus, the heart valve prosthesis affects the natural deformation processes of communicating with their parts of human tissue does not deleteriously.

The numerous openings in the plastic support frame 22 also ensure a perfect attachment possibility for the to be drawn about Dacron fabric 23rd

After completion of the apparent from Fig. 3 the support frame 22, the Dacron fabric is first drawn in the usual manner over and sewn. 1 and 2, killed by fixing and preserved, still an aortic stump 40 having aortic valve of a kangaroo is then subsequently in the coated with the fabric 23 support frame 22 of FIGS. Used, consisting of the annulus fibrosis 18 and springing from these three pocket flaps 15, 16, 17 consists, namely the right pocket flap 15, the a-coronary pocket flap 16 and the left pocket flap 17. the pocket flaps are sometimes referred to as a sail.

To mount the annulus fibrosus 18 is disposed at the bottom of the support frame 22 and adjoining the annulus fibrosus 18 aortic stump 40 which is cut to make up the profile of the edge 24 (Fig. 3a), the inside of the ring portion 13 and the post 12 high out and in the area of ​​the upper edge 24 (Fig. 3,3a) sewn to the fabric 23, wherein a seam is produced 35th According to FIG. 2 of the annulus fibrosus 18 is sewn with the sewing ring 14, whereby a further seam 36 (Fig. 1) results.

In the right pocket flap 15 is the annulus fibrosis 18 still an unrepresented small amount of muscle tissue of the ventricular septum available. Due to the use of a kangaroo aortic this muscle rest is so small in size in the radial direction and also in its strength so insignificant that practically it does not impede the free movement of the right pocket flap 15 during opening of the aortic valve.

After implantation into a human body, the prosthetic heart valve according to the invention operates as follows: If, excess pressure is generated on the bottom in FIG. 1 of the prosthesis, where the left ventricle is, fold the pocket flaps 15, 16, 17 according to the type of valve upwards and give due formation of the inventive free an opening cross section which is at least 70, but generally is 75% and under certain circumstances even 80% of the cross sectional area of ​​the aortic lumen. In this way of occurring between the two sides of the heart valve prosthesis pressure gradient in the opening event will be minimized in the desired extent.

to sweep the pressure conditions around, sweeping the pocket flaps 15, 16, 17 in the apparent from the figures 1 and 2 rest position, wherein in Fig. 2 to come into sealing contact with each other along the lines commissures 21, so that each flow of blood is avoided in the opposite direction.