RU177405U1 - AORTIC VALVE PROSTHESIS - Google Patents

Abstract

The utility model relates to the field of medicine, namely to cardiovascular surgery, and can be used for prosthetics of a failed aortic valve. The proposed prosthesis of the aortic valve consists of an annular supporting frame with three equidistant commissural posts, a wire element, a sash, lining and a sewing cuff. The base of the support frame with a sewing cuff fixed to it has a sinusoidal shape in the scan, which is achieved by arched concave recesses (sines) made along the lower contour of the support frame. The flap apparatus is represented by three cross-linked flaps, each of which is cut in accordance with the uniformity of thickness and / or orientation of the fibers of the biocompatible material, which ensures the identity of the elements inside each copy of the product and increases manufacturability and non-waste production.

Description

The utility model relates to the field of medicine, namely to cardiovascular surgery, and can be used for prosthetics of a failed aortic valve.

Despite the development of medical technology, acquired valvular heart disease remains a significant and widespread disease, covering approximately 2.5% of the total morbidity of the population. Among all valvular defects, damage to the aortic valve prevails in prevalence - its isolated form is found in 33.9% of cases of all valvular pathologies, combined with other lesions in 20.2%.

The most effective way to correct acquired defects of the aortic valve today is prosthetics. Moreover, the proven effectiveness of the use of some devices is up to 25 years of clinical observations, however, modern designs are not without drawbacks that determine the search and improvement of prosthetic heart valves.

From a constructive point of view, the following groups of devices can be distinguished: mechanical and biological, frameless and implantable heart valve prostheses seamlessly (open way or transcatheter).

Known mechanical prosthesis of the aortic valve (Pat 2202990 Ros. Federation, IPC A61F 2/24. Prosthesis of the heart valve / Evdokimov S.V., Nazarov V.M., Melnikov E.V .; applicant and patent holder of the Scientific and Production Enterprise "Med Ing "(RU). - No.2000130654 / 14; application. 06.12.00; publ. 04/27/03, Bull. No. 26 - 6 pp.), Containing an annular body-base with a hole for forming a blood flow, a locking element - sash, as well as the cuff necessary for fixing the prosthesis in the aortic lumen. The structural elements are made of synthetic materials: metals or polymers based on carbon (pyrolytic carbon). A feature of the prosthesis is that the cuff is coated around the perimeter with a smooth, non-wetting, platelet-resistant material made of a film of porous polytetrafluoroethylene (fluoroplastic), which prevents the connective tissue pannus from growing on the cusps and cuff, while maintaining the possibility of the cuff to grow through the cuff through its seating surface.

The disadvantage of a mechanical prosthesis is the presence of rigid inorganic locking elements in the structure that perform the function of the leaflet apparatus, which cannot reproduce the hemodynamics of the native valve. In addition, during the closure of the rigid polymeric valves of the prosthesis and the arising non-physiological swirls of the flow, blood cells, such as red blood cells, are destroyed. Therefore, patients with this type of prosthesis are forced to take lifelong anticoagulant therapy, which significantly reduces their quality of life.

Known prosthesis of the aortic valve (Pat 2473321 Russian Federation, IPC A61F 2/24. Aortic frameless flexible valve prosthesis of the heart / Evdokimov A.S., Evdokimov S.V., Nazarov V.M., Rosseykin E.V. and others. ; applicant and patentee ZOA Scientific and Production Enterprise "Med Ing" (RU). - No. 20111130801/14; application. July 22, 11; publ. 01/27/13, Bull. No. 3 - 9 pp.), which does not have a rigid support frame and containing: a locking element in the form of three flexible petals, interconnected by commissures; elastic cuff for tight sewing of the prosthesis to the fibrous ring; an element located at the base of the valve to connect it to the fibrous ring, as well as an element located at the top of the valve to connect it to the aorta. The absence of a rigid support frame allows more fully use the passage hole of the fibrous ring of the aortic valve, increasing its hemodynamic efficiency. In addition, in the event of a dysfunction of the biological leaf material, its replacement can be carried out using the valve-to-valve technology, or with partial excision of the primary prosthesis.

The disadvantages of this technical solution include the complexity of implantation associated with the high mobility of the prosthesis elements relative to each other. Such mobility can lead to incorrect, asymmetric fixation of the device in the aortic lumen and a violation of its original cylindrical geometry. It is shown that even a slight change in the round geometry of the valve — the occurrence of 10% ellipticity — can significantly impair the locking ability of the valve and, as a result, reduce the effectiveness of the entire intervention.

An additional disadvantage is the complexity of the production of such products, which consists in creating the necessary and sufficient closure zone of the valves, which during operation of the product may be distorted. The manufacturer must provide a margin of sizes for the closure zone - coaptation, and also take into account that during the operation of the valves in the long term, tension and elongation of the biomaterial occurs. Moreover, excessive coaptation of the flaps leads to a violation of the symmetry of their work - to twist, twist the flaps, an uneven pulse load on the flaps, which reduces the life of the structure as a whole.

Another group of aortic valve prostheses are seamlessly implantable devices designed for minimally invasive transcatheter implantation (Pat 125062 Russian Federation, IPC A61F 2/24. Flexible heart valve prosthesis / Rosseykin EV, Bazyle VV, Evdokimov A. S., Evdokimov S.V .; applicant and patentee ZOA Scientific and Production Enterprise “Med Ing” (RU). - No.201136109 / 14; application. 30.08.11; publ. 02.27.13, Bull. No. 6 - 2 s .). This heart valve prosthesis consists of a flexible mesh metal support frame on which a locking element is mounted in the form of three flexible petals made of porous polytetrafluoroethylene. The use of structures of this type allows minimizing the size of the surgical wound due to the lack of open surgical access - sternotomy, aortotomy and performing surgical intervention on the heart without the use of cardiopulmonary bypass. This approach significantly reduces the time of intervention, the patient rehabilitation period, and as a result, reduces the risk of complications and the lethality of all prosthetics.

However, the disadvantage of such prostheses is a more critical selection of patients from the point of view of the anatomy of the implantation site (aortic root), as well as the vascular bed, along which this prosthesis will be delivered. As a result, the presence of massive calcifications, asymmetry of the fibrous ring and / or other elements may not allow the use of this design. Rather frequent complications of seamless fixation of the prosthesis are: dysfunction of the conduction system of the heart when it is compressed by the elements of the prosthesis (up to 30% of cases); dislocation of the prosthesis associated with a lack of fixing ability (radial forces); leakage bypassing the valve due to loose connection of the prosthesis to the wall of the aortic root (up to 18%).

Closest to the claimed technical solution is a prosthetic heart valve, consisting of a flexible polymer support frame with uprights, a wire loop that follows the shape of the upper contour of the frame, sash, cuff and lining of these elements (Pat 76565 Russian Federation, IPC A61F 2/24 Biological prosthesis of the heart valve / Barbarash L.S., Zhuravleva I.Yu., Levaniva R.Kh, Scheglova N.V. applicant and patentee of the NeoKor Public Joint-Stock Company (RU). - No. 2008112609/22; claimed 01.04.08 ; publ. 09/27/08, Bull. No. 7 - 1 p.). The flap apparatus, lining and cuff of the device are made of single-layer biological tissue of appropriate thickness. In this case, the cuff is fixed using suture material along the lower contour of the frame, and the sash apparatus with the bases of the sashes along its upper contour. The wire loop is attached by seams to the lining along the upper contour of the frame and in the area of the vertices of the commissural racks of the frame is additionally connected by seams to the sash apparatus. The combination of wire and polymer frames allows you to achieve the necessary ductility of the sash during its operation, damping the hydrodynamic loads on the commissures and the dome of the sash when it is closed.

The disadvantage of this technical solution is the low adaptation of the design to the geometry of the aortic root, in which the base of the support frame with the sewing cuff is flat, which does not correspond to the anatomy of the fibrous ring of the aortic valve, which in horizontal scanning represents a “sinusoid”.

In addition, all three valves of the prosthetic valve of the heart are cut out of biological material using special patterns in the form of an inextricable flap of complex shape. As a result of this, it becomes necessary to use a large biomaterial preform that is uniform in thickness and fiber orientation, which in practice leads to a large amount of waste during the layout and layout of biological elements in a pattern.

The technical result of the utility model is to improve the anatomical and physiological properties of the supporting frame of the aortic valve prosthesis due to arched concave sines made at the base of commissural racks of the lower frame contour.

An additional technical result is to increase the efficiency of the production cycle and reduce waste biomaterial by cutting each valve leaf prosthesis separately.

It is known that the anatomy of the fibrous ring of the aortic valve is due to the presence of three Valsalva sinuses and commissures between them, while implantation of a prosthesis with a flat base into the three-dimensional sinusoidal structure of the fibrous ring can be non-critical in the immediate period of implantation. However, excessive tension of surgical sutures, cuffs, and especially connective tissue of the fibrous ring, can cause the accumulation of fatigue loads in the long term, and lead to rupture of threads or eruption of patient tissue. Separations arising in this case - fistulas, lead to the discharge of blood bypassing the prosthesis in both phases of the heart beat, i.e. to a malfunction of the valve, which in severe cases can lead to a complete loss of its locking function.

The proposed aortic valve prosthesis consists of an annular supporting frame with three equidistant commissural posts, a wire element, a sash, a lining and a sewing cuff. The geometry of the base of the support frame with the sewing cuff fixed to it has a sinusoidal shape in the scan, which is achieved due to arched concave recesses (sines) made along the lower contour of the support frame at the base of commissural racks. At the same time, the sash apparatus is represented by three sashes that are cross-linked, each of which is cut in accordance with the uniformity of thickness and / or orientation of the fibers of the biocompatible material, which ensures the identity of the elements inside each product instance and increases manufacturability and non-waste production.

The essence of the utility model is illustrated by the drawings, wherein in FIG. 1 shows the complete aortic valve prosthesis (isometry), where 1 is the cusp apparatus of the prosthesis, 2 is the lining, 3 is the sewing cuff fixed along the lower contour of the ring-shaped skeleton and repeating its geometry.

In FIG. 2 shows an annular supporting frame 4 with three equidistant commissural posts 5, at the base of which arcuate concave sines 6 are made, and throughout the entire perimeter - holes 7 for fixing the sash apparatus 1, lining and sewing cuff 3. An additional wire element 8 repeating the upper outline of the support frame.

In FIG. 3 - supporting frame 4 and wire element 8, side view, where 9 is the slope formed due to the difference in thickness of the base and the top of the commissural strut 5.

In FIG. 4 shows three leaflets of the aortic valve in the layout on the biomaterial, where 10 is the leaflet of the leaflet, 11 is the commissural extension of the leaflet.

In FIG. 5 - casement device 1 mounted on a supporting frame 4 using suture material 12.

In FIG. 6 shows a longitudinal section through the ascending portion of the aorta 13 and the fibrous ring 14 of the aortic valve with an implanted prosthesis.

The supporting frame 4 of the claimed aortic valve prosthesis has a ring-shaped base with a thickness of 0.1-3.0 mm, a diameter of 10-30 mm and a height of 10-40 mm with equidistant commissural posts 5, giving the frame a three-vertex shape. In this case, the thickness of the commissural racks 5 is greater at the base and decreases to the apex, thus forming a slope 9, which allows you to increase the effective area of the passage opening during valve operation and the formation of blood flow. On the lower contour of the supporting frame 4, at the base of the commissural posts 5, arcuate concave sines 6 are made with a height of 0.1-10.0 mm, located symmetrically with respect to the central axis of the prosthesis and repeating the geometry of the fibrous ring 14 of the patient’s native aortic valve.

The leaflet apparatus 1 of the aortic valve prosthesis consists of three cusps of the same size, thickness and direction of fibers stitched together. Each leaf has a lunate lobe 10 and lateral commissural extensions 11 designed to fix the flaps to the commissural racks 5 of the supporting frame 4. The creation of the necessary and sufficient coaptation zone is achieved due to the fact that a vertex with a height of 0.1-10 mm is formed in the center of the base of the flap with two-sided slope from 1 to 15 degrees.

The wire element 8 is presented in the form of a thin three-vertex structure with a wire cross section of 0.1-1.0 mm, located along the upper contour of the support frame 4 and repeating its shape. Along the entire perimeter of the wire element 8, the valve flaps of the prosthesis are hemmed, thus forming the geometry of the flap apparatus 1.

Sewing cuff 3 is designed to fix the device in the lumen of the fibrous ring 14 of the patient’s aortic valve. The sewing cuff 3 is cut out in the form of an elongated strip of biomaterial and mounted along the lower contour of the support frame 4, repeating its sinusoidal base.

The supporting frame 4 can be made of homogeneous or dissimilar materials: metals and their alloys (for example, stainless steel), including shape memory or superelasticity (for example, nitinol), polymers (for example, polypropylene), or a combination of the described options. And manufacturing methods can be: casting, milling, turning, molding, heat treatment using additive technologies, as well as other methods or their combination according to well-known methods.

The flap apparatus 1, the lining of the prosthesis 2 and the sewing cuff 3 can be made of biological material, for example, stabilized pericardium of cattle or small cattle, pigs, a kangaroo, or using cell technology and cell engineering from donor material, or biocompatible non-biological materials - polymers, for example PTFE, polyester, polycaprolactone, by other methods or a combination thereof. In this case, the production of the sash apparatus 1, lining 2 and the sewing cuff 3 is carried out using laser cutting or cutting with a surgical tool, or by carving elements, or by a combination of these techniques from a flat or volume sample of material using known technologies, as well as weaving, casting, molding and other methods or their combinations. The resulting elements can be further modified to increase resistance to thrombosis and calcination according to known technologies.

For the manufacture of an aortic valve prosthesis of the required size, a set of components is used, consisting of a support frame 4, a sash apparatus 1, a lining 2 and a sewing cuff 3, in accordance with the technological map and / or technical conditions. The layout and cutting of the valves is carried out taking into account the homogeneity of the biomaterial and the efficiency of the production cycle. After that, the sash apparatus 1 is formed by sewing together the pre-cut three cusps of the valve of the aortic prosthesis along commissural extensions 11 and mounting it on the wire element 8 to give the structure a closed three-vertex shape. After that, cladding 2 is imposed, wrapping the wire element 8 and fixing it with a continuous mattress seam 12. Next, the lined wire element 8 with the mounted casement 1 is fixed along the upper contour of the support frame 4, and the sewing cuff 3 is fixed along the lower contour taking into account the geometry.

The supporting frame 4 with the mounted casement device 1 is covered with a lining 2 and fixed with suture material 12 through holes 7, avoiding the formation of uncovered sections.

The components of the aortic valve prosthesis are combined into a single structure using well-known technologies and approaches: suture material, staples, glue, fixatives, clamps, other methods, or a combination thereof. In this case, it is possible to use homogeneous or heterogeneous materials for additional purposes - inserts, duplicates.

The implantation of the proposed prosthesis of the heart valve is carried out as follows: after providing standard open access to the failed valve of the aorta, the surgeon estimates the volume and degree of intervention, and also selects the required size of the claimed device. The surgeon can conduct a partial decalcification of the implantation site, removal of native valves. After that, the surgeon, by known methods of implanting prostheses into the aortic root 14, fixes the claimed device in the lumen of the fibrous ring 14 supra- or intraannually using sutures 12 or staples, or clamps, or a combination of these elements for the sewing cuff 3. At the same time, the surgeon respects the complementarity of the base valve prosthesis and fibrous ring, i.e. combining the arcuate concave sines 6 of the base of the prosthesis and the base of the sinuses of Valsalva. After preliminary verification of the viability of the locking function of the prosthesis using physiological solution, the intervention is completed according to well-known scenarios.

Claims (2)

1. The prosthesis of the aortic valve, consisting of a support frame, a wire element, a sash, lining and a sewing cuff, characterized in that along the lower edge of the support frame at the base of the commissural racks are made of arcuate concave sinuses with a height of 0.1-10.0 mm, with this, the thickness of each commissural strut decreases from the base to its apex, forming a slope. 2. The aortic valve prosthesis according to claim 1, characterized in that the cusp apparatus of the aortic valve prosthesis consists of three leaflets stitched together, of the same size, thickness and direction of fibers, each leaf having a lunate lobe and lateral commissural extensions intended for fixation sash to commissural racks of the supporting frame.

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