DE10004775A1 - Framework-free heart valve bioprosthesis - Google Patents

Abstract

The invention concerns a biological heart valve prosthesis having no annular support (stentless bioprosthesis) and including a special configuration of fluid inlets and outlets in the valve with the purpose of achieving low resistance perfusion of the connected body areas, a good cleaning process for preventing the formation of thrombosis and simplification of implantation technique by modifying the design of the valve. Possible valve geometry deformation, which are likely to occur in stentless prosthesis, is prevented. The novel bioprosthesis consists of a xenogenic aortic root of a mammalian donor, preferably a pig, that has been optionally pretreated for implantation purposes, for instance with glutaraldehyde, whereby a hole has been placed as an additional coronary outlet at a distance of approximately 120 degrees relative to both original coronary outlets in a surgically or hemodynamically appropriate point, generally in the valve sinus having no original coronary outlet and whereby one of the two original coronary outlets is closed in an appropriate manner from a surgical point of view.

Description

The present invention relates to the field of cardiac medicine and especially a bioprosthesis for use in the treatment of a Heart valve dysfunction in humans.

As is well known, the human heart includes pumping blood through the Body two chambers (the left and right ventricles), each are provided with two flaps for the flow of blood into them and regulate them. Are in the right ventricle this is the tricuspid and pulmonary valves, in the left the mitral and aortic valves. The aortic valve and the pulmonary valve at Humans are both triple-leafed flaps that separate from each other Size and anatomy are similar.

Due to illness, it can happen that one or more valves are not function more normally (as a result of valve damage, one Degeneration or a congenital defect). Often follows especially in the case of the aortic valve a malfunction due to a narrowing the valve opening (stenosis) or from a valve insufficiency, in that the flap is not fully opened or closed.

These have been life-threatening for some time Heart valve malfunctions treated by passing the valve through replaced a prosthesis, with a distinction between so-called mechanical Flaps (where blood flow through one or more closures is regulated by means of a valve), which consist of rigid bodies, and so-called biological valves, consisting of chemically pretreated biological tissue in which the blood flow through natural Valve leaflet is regulated, differs. Draw bioprostheses compared to mechanical flaps by a lower thromboembolic risk.

Regarding the origin of biological heart valve prostheses one differentiates between such allogeneic and xenogeneic nature and speaks accordingly of allo-bioprosthesis (human) and xeno- Bioprosthesis (animal).

35 years ago, the first implantation of a xeno-bioprosthesis in aortic position, which was implanted from bovine (bovine) chemically pretreated pericardium, was successful. Xeno-bioprosthesis has been on the rise since the introduction of glutaraldehyde for the chemical fixation of the collagen scaffold (through an intermolecular cross-linking of the collagen fibrils) of porcine (pig-derived) valves.

Today, the surgeon has four categories for aortic valve replacement of prostheses available: artificial valves (mechanical Double wing prostheses made of pyrolytic carbon), xenografts (consisting of porcine aortic valves or cattle pericardium, with or without scaffolding (stent)), homologous grafts (obtained from the human aorta; scaffold free) and autologous grafts (either patient's own pericardium, mounted intraoperatively on a predetermined Scaffold, or the patient removed and in aortic position implanted pulmonary valve).

The mechanical stress on the xenoprostheses is particularly pronounced in Area of the valve commissures, during the own aortic valve Part of the closing force intercepted by the elasticity of the aortic wall becomes. The valve holder of stented xenografts has significantly less elasticity than the aorta. Here, the Force intercepted by the commissures when the flap was closed.

For this reason, the so-called "stentless" prostheses developed. These prostheses do not have a fixed holding device. she are, like all prostheses, fixed to the aortic annulus and additionally theirs Commissures sewn directly onto the aortic wall, which in turn unites them Part of the mechanical load. The disadvantage of such scaffolding-free flaps consists in particular of a possible warping the valve geometry, which result in prosthesis insufficiency can.

Bioprostheses (xenoprostheses) are used today by various manufacturers offered, for example the Hancock bioprosthesis (later Xenomedica (R) bioprosthesis) and the Carpentier-Edwards (R) valve. At both are procine, glutaralehyde-prepared Aortic valves that are attached to a support ring.

The Hancock bioprosthesis is on a flexible, Dacron-coated circular polypropylene support ring of semi-flexible Texture attached. With the Xenomedica (R) - Bio / prosthesis, the Dacron coated ring supports are anatomical contoured and have a low profile. The flat, flexible Support ring of the Carpentier-Edwards (R) bioprosthesis consists of a cobalt-nickel alloy coated with Teflon and one has an asymmetrical base.

But also biological heart valve prostheses that are free of Support materials are ("stentless bioprosthetic valves") offered commercially. The implantation of glutaraldehyde treated Bioprostheses without ring support promise a better clinical Durability of these flaps because the functional unit between Aortic valve and aortic root is preserved. So there is no unphysiological stress on the flap pockets, and the physiological stress on the flap pockets, and the physiological Hemodynamics with divergent flow without the formation of dead water remains receive.  

Examples of commercially available stent-free bioprostheses the Edwards Prima (R) bioprosthesis are without ring support (Manufacturer: Baxter Edwards AG, CH-6848 Switzerland), the Medtronic Freestyle (R) Aortic Root Bioprosthesis (Medtronic, Inc. Minneapolis, Minn. 55432-3576) and the St. Jude Toronto (R) SPV Bioprosthesis (St. Jude Medical, Inc., St. Paul, Minn. 55117).

Play in efforts to develop novel bioprostheses in addition to the preparation technique of the foreign material, the orientation and Design of the fluidic inlets and outlets in the flap one essential role for a long-term successful function. A Optimal hemodynamics is not only important for a low resistance Perfusion of the connected body areas, but also of large ones Significance for good washout behavior to avoid Thrombus formation. The goal is also the previously complex Implantation technology through modification of the valve design simplify and a possible distortion of the valve geometry with which with stent-free prostheses must always be expected.

The present invention therefore relates to a biological Heart valve prosthesis without ring support (framework-free or stentless Bioprosthesis), consisting of a in a known manner, for Example with glutaraldehyde, pretreated for implant purposes xenogenic aortic root of a donor mammal, preferably the Pig, being in the cylindrical aortic root at a distance of about 120 degrees to either of the two originally existing ones Coronary exits an opening as an additional coronary exit on one surgically or hemodynamically suitable site, generally in the Valve sinus without original coronary outlet, is placed and where one of the two original coronary outlets in surgically suitable, has been closed in a known manner.

The invention is explained in more detail below with the aid of illustrations ( Fig. 1-3, schematic representations, Fig. 4-8 photo reproductions). Show it:

Fig. 1 The schematic top view of a glutaraldehyde-fixed porcine aortic valve cylinder with its two coronary branches 1 and 2 as well as with the three sail valves 4 , 5 and 6 .

Fig. 2 The schematic plan view of the aortic valve cylinder rotated by 120 degrees with respect to Fig. 1, on which, according to the invention, a coronary outlet, here the right coronary outlet 2 , has been closed and a new coronary outlet opening, here the opening 3 , has been produced. As in Fig. 1, the numbers 4 , 5 and 6 identify the three sail flaps.

Fig. 3 The schematic side view of the aortic valve cylinder according to the invention with the openings 7 a and 7 b for receiving the coronary ostia, which correspond to the coronary branches 1 and 3 of Fig. 2. The marking line 8 indicates the area of the aortic root in which modifications can be made intraoperatively without the function of the heart valve prosthesis being impaired. Numeral 9 indicates reinforcement with fabric.

Fig. 4 The original porfine, glutaraldehyde-treated aortic root with the coronary branches 1 (left coronary) and 2 (right coronary) as well as with the marking line 8 (see also Fig. 3) and the reinforcement with tissue (see also Fig. 3).

Fig. 5 The top view of a porcine aortic root modified according to the invention with the coronary branches 1 (original), 2 (original, now closed) and 3 (new). The three sail flaps are visible in the positions marked with the numbers 4 , 5 and 6 .

Fig. 6 The side view of a porcine aortic root modified according to the invention with the closed right coronary outlet 2 and the new outlet 3 as well as the marking line 8 and the reinforcement with tissue 9 . Numeral 10 designates the area of the aortic root below the right coronary exit 2 (now closed), which is originally normally associated with muscle tissue that is usually removed, which area can then advantageously be reinforced with tissue material, as is done here.

Fig. 7 The illustration corresponds to the side view of Fig. 6, whereby by rotating the aortic root modified according to the invention by 180 degrees, the original coronary outlet 1 is in the foreground and the closed coronary outlet 2 is on the left side of the image.

Fig. 8 In this figure, the aortic root according to the invention has been rotated by 90 degrees compared to Fig. 7, so that the coronary branches 1 (old) and 3 (new) can be seen, while the closed branch 2 is not visible.

Claims (7)

1. Framework-free (stentless) heart valve bioprosthesis, consisting from a manner known per se for implant purposes pretreated xenogenic aortic root of a donor mammal, being in the cylindrical aortic root at a distance of about 120 degrees to each of the two originally existing Koro an opening as an additional coronary outlet on one is placed surgically or hemodynamically, and being one of the two original coronary branches in itself has been closed in a known manner. 2. Prosthesis according to claim 1, characterized in that the Pig aortic root (porcine aortic root) as Starting material serves. 3. Prosthesis according to claim 1 and 2, characterized in that the porcine aortic root used as the starting material Glutaraldehyde has been treated. 4. Prosthesis according to claim 1 to 3, characterized in that the opening as a further coronary exit in the valve sine is placed in which there was originally no aortic outlet. 5. Prosthesis according to claim 1 to 4, characterized in that that the right coronary of the two exits is closed. 6. Prosthesis according to claim 1 to 5, characterized in that Markings are applied to the aortic root, which the Mark area of aortic root that is intraoperative can be modified without the function of the prosthesis is affected. 7. A prosthesis according to claim 1 to 6, characterized in that the area of the aortic root below the right coronary Leaving that is originally tainted with muscle tissue that removes is reinforced by fabric material.