Clamped aortic valve

Abstract

The invention relates to a configuration that enables the removal of the fabric used for suturing the aortic valve in the state of the art, and instead allows the outer ring of the internal mechanical aortic valve to be attached from the outside by means of a clamp-like apparatus, with the aortic tissue interposed in between.

Description

[0001] CLAMPED AORTIC VALVE

[0002] TECHNICAL FIELD

[0003] The invention relates to a configuration that enables the removal of the fabric used for suturing the aortic valve in the state of the art, and instead allows the outer ring of the internal mechanical aortic valve to be attached from the outside by means of a clamp-like apparatus, with the aortic tissue interposed in between.

[0004] BACKGROUND

[0005] The aorta is the main artery that originates from the heart and supplies nutrients to the tissues of the human body. Its normal diameter ranges between 2.5 and 3.5 cm. At the point where it exits the heart, just below the openings of the coronary arteries, there is a valve that prevents the backflow of blood into the heart; this is known as the aortic valve. Pathologies that impair the heart's physiological function may develop as a result of narrowing (stenosis) and / or regurgitation of this valve. To prevent these pathologies, which progressively deteriorate the structure of the heart, aortic valve replacement surgery must be performed.

[0006] The structure of these valve is classified as either mechanical or bioprosthetic, depending on the material used. Based on the method of implantation, the valve can be placed with or without sutures. The area through which blood flows within the prosthetic valve is referred to as the effective orifice area. Bioprosthetic valves are either self-expandable or attached to the aortic tissue using sutured methods. At this stage, aortic valve are typically made from bovine pericardium. Mechanical valves, on the other hand, are rigid structures made from carbon materials. For both bioprosthetic and mechanical aortic valves to function stably, they must first be anchored to a secure annular structure. Subsequently, in order for this stable structure to be implanted into the aortic tissue, a fabric that allows suturing is required. This fabric ensures that the valve ring can be securely sewn to the aortic tissue. The main issue here is that the fabric surrounding the ring has a certain thickness, which occupies a portion of the space inside the aorta. This increases the outer diameter of the valve, functionally reducing the effective orifice area (EOA) through which the blood flows. A reduction in this area decreases the outflow space in front of the heart, which functions as a pump, leading to increased cardiac workload and strain on the heart muscle. To prevent this reduction, it is necessary to expand the valve area while minimizing the thickness of the frame used to secure the valve to the aorta. The removal of the fabric surrounding the valve in our invention effectively achieves this goal. For example, eliminating 2 millimeters from both the top and bottom edges of a 30 mm diameter valve results in a total increase of 4 mm in diameter for the circular structure. A sample calculation using the area formula IT X r2shows that increasing the radius from 15 mm to 17 mm increases the area from 225 mm2(15 x 15) to 289 mm2(17 x 17). The difference, 289 - 225 = 64 mm2, represents a 64 / 225 = 28.4% — approximately a 30% — increase in area. This increase allows blood to exit the heart into the body more easily and in greater volume, thereby reducing the heart’s energy expenditure.

[0007] Aortic valve replacement is performed using either mechanical or biological prosthetic valves. This method has been used safely for many years. However, since these valves are made of materials foreign to the body, thrombus (clot) formation that impairs valve function is a significant concern. The medication used to prevent clot formation is Coumadin. However, the use of this drug is problematic during pregnancy, as it can adversely affect fetal health.

[0008] Biological aortic valves are made from various living tissues (such as the pericardium of pigs or cows) and are designed to mimic the physiological shape of the native aortic valve. One of the main advantages of biological valves is that they do not require lifelong use of Coumadin, making them particularly beneficial for certain patient groups. Another advantage is that, due to their similarity to natural aortic tissue, they tend to function more physiologically. However, their primary disadvantage is their tendency to degenerate more quickly than mechanical valves, with a typical lifespan of 15-20 years. Therefore, they are more suitable for elderly patients. Mechanical aortic valves, on the other hand, can function effectively for many years, but the necessity for lifelong Coumadin therapy is a significant drawback.

[0009] In general, when the literature is reviewed, there is no significant difference between biological and mechanical valves in terms of patient survival, clinical outcomes, and quality of life. However, most studies report that the mean and peak transvalvular pressure gradients tend to be higher in the biological valve group (“Biological versus mechanical aortic valve replacement in non-elderly patients: a single-centre analysis of clinical outcomes and quality of life’’ Fabio Stocco, Assunta Fabozzo, Lorenzo Bagozzi, Chiara Cavalli, Vincenzo Tarzia, Augusto D’Onofrio, Giulia Lorenzoni, Valentina Chiminazzo, Dario Gregori, Gino Gerosa, Interactive Cardiovascular and Thoracic Surgery, Volume 32, Issue 4, April 2021 , Pages 515-521 , https: / / doi.org / 10.1093 / icvts / ivaa306).

[0010] The diameter of the blood flow passage within a mechanical aortic valve is approximately 4-6 mm smaller than the diameter of the native aortic tissue. This reduction is due to the thickness of the supporting frame required to stabilize the mechanical valve, as well as the presence of a sewing ring that allows the valve to be securely sutured to the aortic tissue.

[0011] In valve implantation performed in this manner, if the sutures are placed too superficially, the aortic tissue may tear; if they are placed too deeply, the cardiac conduction pathways may be damaged. In some patients, sutures may cut through the aortic tissue postoperatively, leading to perivalvular leakage. This valve implantation technique causes a decrease in the effective orifice area (EGA), which is calculated as the square of the radius, due to the reduction in valve diameter. It also leads to a pressure gradient above and below the valve caused by resistance to the pressure generated by the heart, and over the years, this resistance can result in deterioration of the heart muscle tissue. Additionally, the fabric structure that facilitates the implantation of small-diameter mechanical valves poses a risk as a potential site for thrombus formation and infection, and may also contribute to perivalvular leakage, making it another disadvantage of the method.

[0012] Another problem addressed by the invention is the inability to implant even the smallest-diameter mechanical valves into the aorta in cases where valve replacement is required due to valve pathologies associated with a narrow aortic root. Since the invention provides approximately a 30% increase in valve area for valves with the smallest available diameter, it eliminates the need for extensive root enlargement surgeries typically performed in such cases — procedures that significantly increase mortality and morbidity risks in patients — and thus contributes to reducing these risks.

[0013] AIM OF THE INVENTION

[0014] One aim of the invention is to increase the effective orifice area (EOA) by reducing the thickness of the outer frame of the valve. Another aim of the invention is to minimize the damage caused by sutures to the aortic tissue.

[0015] Another aim of the invention is to reduce the potential for paravalvular leakage around the valve.

[0016] A further aim of the invention is to enable the heart to deliver more blood to the body with less energy expenditure through an aortic valve with a larger area. Studies involving echocardiographic examination of transvalvular pressure gradients (the pressure difference above and below the valve) have shown that increasing the valve area has a positive effect on the gradient. This improvement increases both the patient's lifespan and quality of life.

[0017] As a solution to the problems described in the “Prior Art” section, the present invention relates to a structure in which the fabric used for suturing the valve is eliminated and instead, the outer ring of the mechanical aortic valve is fixed externally with a clamp, while the aortic tissue remains in between. In this way, the factor causing narrowing of the diameter is removed, allowing for a larger valve area. The invention can also be applied to bioprosthetic valves. However, in bioprosthetic valves, the ring and the surrounding fabric structure are not as thick as in mechanical valves. Therefore, the effective orifice area (EOA) can be increased by approximately 20%, rather than the level achievable with mechanical valves. In the valve body, in the vertical section, a convex structure is shown in detail view B in Figure 4, which is intended to provide better stabilization to the aortic tissue via an external clamp. At the center point of this convex system, a slight 1 mm elevation ensures a stable and robust body-to-aorta connection.

[0018] FIGURE LIST

[0019] Figure 1 . General view of the invention

[0020] Figure 2. Front view of the invention

[0021] Figure 3. Vertical sectional view A-A of the aortic valve body and the region where it approaches the upper part of the clamp

[0022] Figure 4. Detailed view B showing parts 7 and 4 without the illustration of the aortic tissue in between

[0023] Figure 5. Vertical view of the invention fixed with a clamp

[0024] Figure 6. View of the clamp locking apparatus REFERENCES IN THE FIGURES:

[0025] 1. Housing

[0026] 2. Fixing apparatus

[0027] 3. Protrusion

[0028] 4. Body

[0029] 5. Upper valve

[0030] 6. Lower valve

[0031] 7. Clamp

[0032] DETAILED DESCRIPTION OF THE INVENTION

[0033] Figure 1 shows a general view of the clamped aortic valve according to the invention. The mentioned product is characterized by comprising valve structures formed by the body (4), upper valve (5), and lower valve (6), a clamp (7), and a housing (1), a fixing apparatus (2), and protrusions (3) on the clamp (7) that are used to compress the clamp with the aid of forceps. The protrusion (3) located on the clamp (7) and the fixing apparatus (2) serve as support during the compression of the clamp (7) with the aid of a pliers. After the clamp (7) is sufficiently tightened, the housing (1), through which the extended end of the clamp (7) can pass, ensures stabilization during the tightening process. Once the clamp (7) reaches the desired tightness, it is secured by affixing the fixing apparatus (2) using the oval rigid metal component.

[0034] In the A-A sectional view presented in Figure 3, a side view of the mechanical valves (5, 6) and the clamp (7) securing them to the aortic tissue is shown.

[0035] The valves (5, 6) are attached to the body (4) using a method that allows movement, unlike a fixed hinge. This enables them to perform their function of opening during systole (when the heart pumps blood to the body), allowing blood to flow from the heart into the systemic circulation. During diastole (the phase in which blood returns to the heart from the body), the valves close to prevent the backflow of blood into the heart. In summary, they function effectively as a valve by ensuring unidirectional blood flow.

[0036] The placement of the aortic valve, the components and their functions of which are described above, is carried out by first removing the malfunctioning native aortic valves, then inserting the prosthetic valve into the aorta, and finally securing it at the appropriate anatomical location — just below the coronary orifices — by means of an external clamp.

[0037] In the A-A sectional view shown in Figure 3 and the B detailed view shown in Figure 4, the vertically positioned main body (4) of the invention and a portion of the clamp (7), which secures the body in place by applying pressure from the outside of the aortic wall (not illustrated in the figures), can be seen.

[0038] In Figure 6, at the locking point, the diameter and wall thickness of the aorta and the valve body are measured, and the appropriate clamp diameter is selected to ensure stabilization between the body and the aorta in a way that prevents blood leakage and fits the proper anatomical structure. Figure 6 shows the joined state of the two end portions of the clamp selected in accordance with the diameter of the main body and the aorta. The connection section has been designed as a robust metal structure, and a portion of the clamp (7) consists of a fabric made from durable Dacron material. The two ends of the clamp pass through each other to form a circular ring. In order for the clamp to become a locked, complete ring at the designated diameter, two separate protrusions resembling a projection must interlock. To enable this locking, a rigid oval metal fastener called the fixing apparatus (2) has been designed. The characteristic of the protruded structure here is that, when the two parts are joined, the circular ring form of the clamp (7) appears as a “T” shape, and after the oval fixing apparatus (2) is placed, it transforms into an “I” shape with the thickness of the crossbar of the original “T.” In other words, the protrusions (3) inside the oval fixing apparatus (2) resemble a vertically bisected “T” shape.

[0039] The protrusions (3) located on the clamps (7) and the fastening part (2) serve as support during the tightening of the clamp (7) with pliers. After the clamps (7) are sufficiently tightened, the housing (1) through which the extended end of the clamp (7) passes ensures stabilization during the clamping process. As shown in Figure 4, a convex structure formed inside the clamp (7), similar to the convex structure created on the body (4), is visible to ensure the stability of the body (4) within the aorta.

Claims

CLAIMS1 . 1 . An aortic valve comprising an upper valve (5) and a lower valve (6) within a body (4), characterized in that it comprises: a clamp (7) having a convex structure on the part that contacts and rests on the body (4); a protrusion (3) and a fixing apparatus (2) located on the clamp (7), both configured to assist in tightening the clamp (7) with pliers; and a housing (1) through which the extended end of the clamp (7) passes after sufficient tightening, providing stabilization during the clamping process.

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