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AORTIC RING AND ANCILLARY DEVICE FOR IMPLANTING IT
 The present invention relates to an artificial aortic ring intended to reduce or contain the normal aortic ring in a number of diseases of the cardiac valves. The invention also relates to ancillary devices and methods for implanting this ring.
 The natural aortic ring is a fibromuscular structure which is able to expand in each cardiac cycle. It has a sigmoid shape made up of three commissural summits and three nadirs corresponding to the point of insertion of the aortic valvules.
 Insufficiency of the aortic valvules generally requires reparative surgery. This is particularly so in the case of dystrophic valvular insufficiency, for example annuloaortic ectasia, isolated valvular dysplasia, or bicuspid aortic valve disease.
 The present invention proposes to reduce or contain, when necessary, the diameter of the aortic ring, in a subvalvular and/or supravalvular position, especially in the case of dystrophic aortic valve insufficiency, or in the case of aortic valve replacement by means of a valve with no reinforcement, making it necessary to contain the ring in a subvalvular and/or supravalvular position.
 Among these valve insufficiencies, a distinction will be made between those involving lesions of the valvules, in particular acute articular rheumatism, endocarditis, and traumatic tears, and those without valvular lesion and with bicuspid or tricuspid valves which are macroscopically normal, especially annuloaortic ectasia, isolated valvular dysplasia, bicuspid aortic valve disease, and Laubry-Pezzi syndrome.
 The subject of the invention is an aortic ring made of a flexible, suturable and biocompatible material, sterile or sterilizable, having a height preferably at least equal to 2 mm and having a length, in the implanted state, making it possible to maintain a normal aortic ring diameter, said ring comprising, or being able to be combined with, means for holding the ring in a closed position in its site of implantation.
 The dimensions of the ring are advantageously such that the ring can be implanted around the aortic root, and in a subvalvular position.
 The height of the ring according to the invention is advantageously greater than 1 mm and preferably between 2 and 4 mm. The choice of height of the ring can of course be tailored to the size and physiology of the patient.
 The ring can comprise closure means.
 Thus, in a particular embodiment, it can be made from the outset in a closed ring shape, in cases in particular where the surgical intervention involves complete resection of an aortic segment, permitting placement of a ring that is initially closed.
 In another embodiment, these means can comprise means of closure or of fastening which are already in place, allowing a ring which is initially open to be formed into a circle and closed at both ends. These means can be staples or threads, for example, initially engaged in the ring, or any other means of closure.
 Finally, the ring according to the invention can also be in the open form of a band which initially has no means of closure, this closure being able to be achieved, for example, by suturing.
 In the case of a ring which is initially closed, it is advantageous to provide sets of rings of different heights and different diameters. However, it is also possible to conceive of having just one height with different diameters and of allowing the surgeon to reduce the height to the desired value by cutting the circular ring.
 In the case of a ring which is initially open, the ring is advantageously in the form of a band whose two ends will be able to be joined together after placement around the aortic segment to be reduced or contained. In this case too, it is possible to provide either a set of bands of different heights and/or lengths, or a ring which in the band state has a maximum length, and the ends of the ring which protrude after closure can be eliminated by cutting either before or after implantation.
 The ring according to the invention is made of a flexible, suturable and biocompatible material. This material, which must obviously be sterile, is preferably produced in a textile form permitting straightforward fixation by suturing and/or closure of the ring, for example by a thread. The material used is preferably polytetrafluoroethylene, for example in woven form, although other biocompatible materials can be used, such as, for example, Dacron. The person skilled in the art presently uses vascular prostheses made of Dacron or of polytetrafluoroethylene, and these materials are well known to him.
 In a refined embodiment, the material can be elastic so as to exert a pressure which makes it possible to reduce the aortic diameter in the diastolic phase, respecting the physiology of the normal aortic ring, while expanding for an increase in systolic diameter. In this case, the variation in diameter is preferably limited to a less than 10% increase in diameter of the prosthetic ring for a pressure greater than 140 mmHg. For expandable rings, use will be made of, for example, polytetrafluoroethylene or silicone.
 Preferably, the ring according to the invention can exist in three sizes defined by the diameter of the ring. A first size is advantageously of the order of 23 mm, the second of the order of 25 mm, and the last of the order of 27 mm.
 In the case of an expandable ring, the increase in diameter in each of these cases is preferably limited to a maximum of 2 mm.
 The cross section of the ring can be analogous to that of the cut of a fabric having a thickness for example of between 2 and 4 mm. However, any other shape of cross section can be provided, for example oval or others, formed for example by knitting.
 The invention also relates to the use of a ring made of a flexible, suturable and compatible material, having a height preferably at least equal to 2 mm and preferably of between 2 and 4 mm, initially open or closed, for production of an aortic ring, said aortic ring having in particular the characteristics listed above, and said aortic ring comprising or being combined with means for holding the ring in a closed position in its site of implantation, in particular in a subvalvular position or possibly also in a supravalvular position.
 The invention also relates to an ancillary device for implanting an aortic ring according to the invention and comprising an annular frame or open arc optionally connected, preferably in a detachable manner, to a rod which is substantially transversal with respect to the plane of the ring or of the arc, means being provided to hold the aortic ring according to the invention along this frame or arc in a position which is such that, when suturing the aortic ring around the aorta, the aortic ring cannot locally fold or pucker during suturing. An ancillary device having the shape of an open arc can be used when the aortic ring according to the invention is implanted in a subvalvular position without separation of the coronary vessels.
 The means for fixing the aortic ring on the ancillary device can be of different types, for example a system of foldable tabs or other fixing means holding the aortic ring against the frame. Alternatively, this fixing can be effected by one or more threads connected to the frame and holding the aortic ring along this frame without any possibility of puckering or folding, such a thread being able to be released subsequently, for example by sectioning.
 The invention also relates to a method of implanting an aortic ring according to the invention.
 This method involves positioning the ring around and outside the natural or artificial aortic wall.
 According to a first mode of implementation, the method involves performing an aortic subvalvular annuloplasty by placing and implanting the ring in a circular plane below the nadir of each sigmoid valve. The ring is preferably fixed by U-shaped stitches, for example five to six uniformly spaced stitches, which are passed from the inside outward.
 For example, in the case of an aneurysm of the aortic root, the method consists in replacing the aortic root with a tubular implant, for example of Dacron, indented with three Valsalva neo-sinuses, combined with aortic subvalvular annuloplasty round the subvalvular base of the reconstituted wall, before reinsertion of the coronary vessels.
 In a second mode of implementation, which moreover can be combined with the first one, the method involves performing supravalvular annuloplasty, at the level of the sinotubular junction by implantation of the ring, preferably using commissural U-shaped stitches passed from the inside outward, for example three stitches.
 For example, particularly in cases of isolated valvular dysplasia without aneurysm of the aortic root, subvalvular annuloplasty and supravalvular annuloplasty are performed, conserving the native aortic root, the two rings being disposed at the two aforementioned locations.
 Other advantages and characteristics of the invention will become clear on reading the following description based on a nonlimiting example and with reference to the attached drawing, in which:
 FIG. 1 shows a diagrammatic view of a closed ring according to the invention,
 FIG. 2 shows a diagrammatic view of a ring which is initially open,
 FIGS. 3 through 7 show diagrammatic views of different steps in implanting an aortic ring according to the
invention in a procedure involving supravalvular conservation combined with subvalvular annuloplasty,
 FIG. 8 shows a view of the result after longitudinal opening of the aortic root to permit better understanding,
 FIG. 9 shows a photographic view at the stage in FIG. 7, showing the detailed implantation of the ring,
 FIG. 10 shows a diagrammatic view during surgery in the context of supravalvular and subvalvular aortic annuloplasty, with conservation of the native aortic root,
 FIG. 11 shows a view at the same stage after longitudinal opening of the aortic root to permit better understanding,
 FIG. 12 shows a view similar to that in FIG. 11, but after resection of the native Valsalva sinuses,
 FIG. 13 shows a diagrammatic view of a first ancillary device for implanting the aortic ring,
 FIG. 14 shows a view of a modified ancillary device.
 Reference is first made to FIG. 1.
 FIG. 1 shows a ring made of Dacron (trademark), this ring 1 being made of flexible Dacron in the form of an impermeable knit which is usual in vascular surgery.
 In the circular state, this ring has a diameter of 23, 25 or 27 mm depending on the size of the ring. The height of the ring is 2 mm.
 This ring can be fitted in place after total resection, permitting separation of the aorta, for engagement around the remaining segment.
 FIG. 2 shows a ring which is initially open and in the form of a band 2 made of the same material as in FIG. 1, and having a length equivalent to the perimeter of the circle corresponding to the desired diameter. By way of example, this ring has two threads 3, 4 passed through it and emerging at both ends in order to permit closure by a knot.
 This closure device can be replaced by any other closure device which is strong and biocompatible, for example clips or fasteners.
 The band can also be without a thread and can then be closed using knots of non-absorbable suture thread or the like.
 The length of the band can be itD, D being the diameter, for example one of the aforementioned diameters.
 The band can also be of greater length, particularly in the case where it does not have ready fastening means, so as to allow it to be cut to the length desired by the surgeon.
 Reference is now made to FIGS. 3 through 9
which show a ring being implanted in an operation involving supravalvular aortic conservation and subvalvular annuloplasty.
 FIG. 3 shows the native root 10 of the aorta after resection of the three Valsalva sinuses, revealing the three sigmoid valves 11. The coronary vessels 12 have been detached. Six U-shaped threads 13 have been placed in a circular plane below the nadir of the sigmoid valves 11, these six threads being in standby to receive the aortic ring.
 As will be seen in FIG. 4, a prosthesis 14 is then presented for replacement of the ascending aorta, said prosthesis being made of Dacron and indented to form three Valsalva neo-sinuses 15.
 In FIG. 5, the prosthesis 14 has been implanted and sutured.
 In FIG. 6, the surgeon has now engaged, and lowered onto the ascending aortic prosthesis 14, an initially closed aortic ring 1 which is then secured around the aortic root, at the location marked by the threads 13 which are passed through the ring 1, drawn and tightened to form knots 15.
 FIG. 7 shows the result once the operation has been completed. The coronary vessels 12 have been reinserted at two of the competent neo-sinuses 15, and the continuity of the aorta has been re-established at the upper end of the prosthesis 14.
 FIG. 9 illustrates the end of the phase of descent of the aortic ring and its fixation, then reinsertion of the coronary vessels.
 An anatomical view has been shown in FIG. 8, illustrating the position of the aortic ring 1 situated in a plane corresponding to the root of the aorta and below the nadir of the sigmoids.
 By virtue of the invention, it has thus been possible, by means of the subvalvular annuloplasty achieved by the aortic ring 1, to strengthen the aortic root and maintain its diameter during the diastolic phase. The valve function has thus been re-established without any intervention of the valves themselves.
 Referring to FIG. 10, this shows the position occupied by rings, namely a subvalvular ring 2 and a supravalvular ring 1 in the case of valve repair with conservation of the native aortic root, or in the case of a valve replacement without reinforcement.
 The subvalvular position of the ring 2 corresponds substantially to the position shown in FIGS. 4 and 5. Only the implantation technique varies. This is a ring which is initially open and is passed under the coronary ostia without these being detached from the native aortic root.
 The supravalvular ring 1 surrounds the three sites of commissural implantation of the sigmoid valves.
 In practice, the two rings can be placed on aorta ends and/or implants completing the aorta and restoring the sinuses.
 FIG. 12 shows an anatomical view of these implantations, with resection of the native Valsalva sinuses.
 Referring to FIG. 13, this shows an ancillary device 20 intended to facilitate the implantation and suturing of an aortic ring 1 so as to avoid the risks of malpositioning and folding of the ring. This ancillary device 20 comprises a rigid or semi-rigid frame 21 having substantially the diameter of the aortic ring 1 and being fixed to the end of a handle 22, preferably via a removable fixing means 23. The ring 1 is positioned under the annular part 21 and is held against the latter by foldable tabs 24 spaced at regular intervals.
 The surgeon takes the assembly consisting of ancillary device and ring and lowers it to the desired position, for example the subvalvular position shown in FIG. 7 or the supravalvular position shown in FIG. 10. Once the assembly is in place, he releases the handle 22 and the fixing device 23 then proceeds to suture the ring 1 in position, said ring being prevented from moving or folding by virtue of the presence of the annular frame 21. At the end of implantation of the ring, the surgeon deploys the arms 24 and withdraws the frame.
 FIG. 14 shows another embodiment of an ancillary device, this time comprising a rigid or semi-rigid frame in the form of an open arc 25, which is preferably deformable. A ring 2, which is initially open, is fixed in place under the arc 25 by means of foldable arms 24 or any other fixing means, for example with the aid of threads that have been drawn tight. The assembly formed by the intially open ring and the frame 25 is mounted around the aortic root by passing the frame 25 with its ring, by rotation, under the coronary vessels, without detachment of these. After suturing of the ring, then release of the arc 25, the latter can be disenagaged from the coronary vessels, by reverse rotation, and withdrawn.
1. An aortic ring made of a flexible, suturable and biocompatible material, having a length, in the implanted state, making it possible to maintain a normal aortic ring diameter, said ring comprising, or being combined with, means (3, 4) for holding the ring in a closed position in its site of implantation.
2. The aortic ring as claimed in claim 1, wherein said ring has a dimension allowing it to be implanted around the aortic root, in a subvalvular position and beneath the coronary vessels.
3. The aortic ring as claimed in claim 1 or 2, wherein said ring has a height greater than 1 mm and in particular from 3 to 4 mm.
4. The aortic ring as claimed in claim 1, said ring having a closed annular shape.
5. The aortic ring as claimed in either of claims 1 and 3, said ring being made in the form of a band (2) which is initially not closed.
6. The aortic ring as claimed in claim 5, said ring having means of closure (3, 4) or of fastening which are already in place, allowing the ring, which is initially open, to be formed into a circle and joined at its two ends.
7. The aortic ring as claimed in claim 6, wherein said means are staples or threads.
8. The aortic ring as claimed in one of claims 1 through 7, wherein said ring is made of a textile material permitting simple fixation by suturing of the ring and/or closure.
9. The aortic ring as claimed in claim 8, wherein the material used is polytetrafluoroethylene or Dacron or silicone, in particular in a woven or knitted form.
10. The aortic ring as claimed in one of claims 1 through 9, wherein the material is elastic so as to exert a pressure which makes it possible to reduce the aortic diameter in the diastolic phase, respecting the physiology of the normal aortic ring, while expanding for an increase in systolic diameter.
11. The aortic ring as claimed in claim 10, wherein the variation in diameter is limited to a less than 10% increase in the diameter of the prosthetic ring for a pressure greater than 140 mmHg.