The invention relates to the test apparatus for mitral and tricuspid valve prosthetic ring annuloplasty surgeries. Test apparatus is designed to help cardiac surgeon to choose the most suitable prosthetic ring size to be used during mitral and tricuspid valve surgery.

The heart has a four chamber structure. It consists of two atriums and two ventricles. With a wall in the middle, the cavities of the heart are divided into right and left halves. Atriums are upper chambers of the heart which receive blood returning from the venous circulation (right atrium) or from the lungs (left atrium). Ventricles are the main pumping chambers of the heart. The right ventricle’s function is to pump oxygen depleted (venous) blood to the lungs through main pulmonary artery. The left ventricle pumps oxygen rich (arterial) blood into the systemic circulation through the aorta.

Blood flows in only one direction inside the heart. This is achieved by the valves in the heart. There are four valves in the heart. Aortic valve is located between the left ventricle and the aorta. Pulmonary valve is located at the origin of the main pulmonary artery. Atrioventricular valves separate atriums and ventricles. After filling of the atriums, atrioventricular valves open and blood flow through these valves to enter ventricles. Ventricular contraction increase pressure in the ventricular chambers and forces inlet (atrioventricular) valves to close in order to prevent retrograde flow of blood into the atriums. High ventricular chamber pressure opens the outlet (aortic and pulmonary artery) valves to free blood into the arterial circulation. The right atrioventricular valve is called tricuspid valve and is positioned between the right atrium and ventricle. The left atrioventricular valve is called mitral valve and is positioned between the left atrium and ventricle. The valves in the heart have thin flaps of tissue called leaflets. Tricuspid valve have three leaflets and mitral valve have two leaflets. The base of atrioventricular valve leaflets are firmly attached to a ring like fibrous structure called annulus. These leaflets open towards ventricles during blood passage and then close by kissing each other. Leaflets are attached from their free margins to the papillary muscles with fibrous strings called chorda tendineae. Papillary muscles are located in the ventricles. An atrioventricular valve close the whole aperture between the atrium and ventricle in its closed position and resist to open to the wrong (atrial) side by these valvular and subvalvular structures functioning properly. The annulus also contracts to reduce its surface area during ventricular contraction to help tight closure.

Any pathology that disrupt the proper functioning of these valvular and subvalvular components (annulus, leaflets, chorda tendineae, papillary muscles) result in incompetency of the valve. Annular dilatation, leaflet perforation, chorda tendineae elongation or rupture, papillary muscle dysfunctions are some of the main causes of atrioventricular valve insufficiency. Atrioventricular valve insufficiency cause serious problems on the patient such as fatigue, shortness of breath, lower body edema, rhythm disturbances, renal dysfunction, hepatic dysfunction and severe heart failure.

Atrioventricular valvular insufficiency may be corrected surgically either by replacing the incompetent valve with a prosthetic valve material (valve replacement surgery) or repairing the native valve tissue (valve repair surgery).

In the valve replacement surgery technique, the incompetent valve tissue is removed from the body and a new prosthetic valve material is sutured to the valve position. There are two types of prosthetic (mechanical and biological) heart valve material available currently. Both of them have some advantages and disadvantages over each other. Durability and thrombogenicity are two main concerns of prosthetic heart valves. Mechanical prosthetic heart valves are durable but thrombogenicity is a big problem. These patients must use anticoagulant medication for a life long period in order to prevent clot formation and thromboembolic complications. On the other hand, anticoagulant medicines are also not safe. They increase the risk of bleeding singificantly. The patient is kept under close follow up for potential bleeding and thromboembolic complications after mechanical heart valve replacement surgery. Bioprosthetic heart valves are mostly made of pericardial tissue of cows or pigs’ heart valve leaflets. Human donor valves are rarely used. Their main advantage is the lower risk of clot formation on the valve tissue. The patient will most likely don’t need to use anticoaguation for too long but durability is an issue. Bioprosthetic valve structural deterioration occurs in 10-15 years. The patient may require another replacement surgery at some point.

In current guidelines, heart valve repair surgery for valvular insufficiency, is higly recommended over replacement surgery. Thanks to the preservation of the patient’s own valve structures in valve repair surgery, the possible risks associated with the use of anticoagulant drugs for a life time long are avoided. There are several repair techniques described for mitral and tricuspid valve insufficiency, according to the underlying pathology. Some are easy to perform and some need quite expertise over the technique. Which technique will be used depends on the surgeon’s skills and experience but it is strongly recommended to stabilise the atrioventricular valve annulus with a prosthetic ring to increase the durability of the repair.

Heart-lung machine (cardiopulmonary bypass) is mandatory to perform open-heart surgery. Heart valves are located inside of the heart and, to be able to operate on a structure located in the heart, the heart must be kept arrested during surgery. The patient is connected to the heart-lung machine in order to maintain vital activity throughout the open heart surgery. After completion of the surgical prosedure in the heart, the heart cavities are closed and the patient is weaned from cardiopulmonary bypass.

As mentione above, all repair surgeries are accomplished with a prosthetic ring annuloplasty procedure. Prosthetic ring annuloplasty surgery aims to reinforce and remodel the valve annulus with a prosthetic ring material and improve the durability of the valve repair surgery. For this purpose, a suitable size prosthetic ring material is stiched to the valve annulus.

The prosthetic ring materials used in mitral and tricuspid ring annuloplasty surgeries have different shapes and the characteristics of the manufacturer, and they generally have dimensions between 26-36 mm. Each company has produced its own measuring apparatus (ring sizer) in order to ensure the selection of the appropriate ring size. Following placing sutures through the valve annulus, cardiac surgeon has to choose the most suitable prosthetic ring size for the patient to enable a competent valve. For this purpose, surgeon use ring sizer to decide the correct ring size. The decision needs some expertise particularly if a down or over size of the annulus diameter is to be performed for remodelling. Wrong size selection result in failure of the whole repair procedure.

Following selection of the suitable prosthetic ring size for the patient, surgical threads placed in the annulus of the valve are passed through the selected prosthetic ring and knotted after the prosthesis is lowered on the annulus. Then, the valve competency is tested visually by means of pressurized fluid. Pressurized fluid injected into the ventricle forces the repaired valve to close. Surgeon looking at the valve through the atrial side evaluates the competency of the valve. If the result is satisfactory, the surgeon close the heart cavities and recheck the final result with echo cardiographic imaging performed in the operation room before the closure of the chest.

Selecting the appropriate size prosthetic ring is a key factor that directly affects the success of thesurgery. Using a prosthetic ring with a much smaller size than it should be may cause severe narrowing in the annulus tissue, and the use of a larger ring may cause the continuation of the valve insufficiency. In case of an inaccurate ring size insertion, cardiac surgeon has to cut stiches that hold the prosthetic ring in place, remove the prosthesis and throw it away. In order to place a new size (larger or smaller) prosthetic ring, surgeon has to put new stitches to the delicate tissue of valve annulus that has already been damaged with the previous sutures. For this reason, choosing the appropriate size prosthetic ring requires serious experience. This is one of the obstacles to the widespread use of atrioventricular valve repair surgeries. The test apparatus for mitral and tricuspid valve prosthetic ring annuloplasty operations has been developed in order to find a solution to these problems. The test apparatus is designed to show the final result of the chosen prosthetic ring size before permanently fixing it on the valve annulus. In this way, the surgeon will have an idea about its suitability without opening the sterile packaged prosthetic ring. This will help surgeon, to chose the appropriate prosthetic ring size without hesitation. Based on the thought of “any invention reducing the need for experience will make surgical approach simplified”, the test apparatus is expected to facilitate mitral and tricuspid valve prosthetic ring annuloplasty operations. Thus, helping atrioventricular valve prosthetic ring annuloplasty surgeries done more widespread is aimed.

The system made to achieve the purpose of the test apparatus for the mitral and tricuspid valve prosthetic ring annuloplasty surgeries of the present invention is explained below by referring to the attached figures. These figures;

Figure 1 - Detailed View of The Test Apparatus For Mitral And Tricuspid Valve Prosthetic Ring Annuloplasty Surgeries

Figure 2 - Detailed View of The Test Apparatus For Mitral And Tricuspid Valve Prosthetic Ring Annuloplasty Surgeries

Figure 3 - Detailed View of The Test Apparatus For Mitral And Tricuspid Valve Prosthetic Ring Annuloplasty Surgeries

Figure 4 - General View of The Test Apparatus For Mitral And Tricuspid Valve Prosthetic Ring Annuloplasty Surgeries

The parts in the figure are numbered one by one and the parts corresponding to these numbers are explained below:

1 - The Test Apparatus For Mitral And Tricuspid Valve Prosthetic Ring Annuloplasty Surgeries

1.1- Test ring

1.2- Thread gap

1.3- Thread channel The subject of the invention is the test apparatus for mitral and tricuspid valve prosthetic ring annuloplasty surgeries (1), and it consists of the test ring (1.1), the thread gap (1.2) and the thread channels (1.3).

The test apparatus (1) for mitral and tricuspid valve prosthetic ring annuloplasty surgeries is designed to show the final result of valve repair before tying the sutures and permanently fixing the prosthetic ring to be used. The similar size and design of the test apparatus with manufactured prosthetic rings will facilitate to evaluate the competency of the valve by deploying different sized test apparatuses without giving harm to the delicate annulus tissue.

For this purpose, following the measurement of the mitral or tricuspid valve annulus with the manufacturer’s ring sizer, a test apparatus (1) designed with the same type and size is used to evaluate the valve competency before final decision is given.

It works by passing the annular sewing threads inward through the thread gaps (1.2) positioned at certain intervals on the outside of the test ring (1.1), lowering the test ring (1.1) on the valve annulus , placing the sewing threads into the thread channels (1.3) and pulling them sequentially to lateral sides to keep sutures tightened inside the thread channels.

The thread channel (1.3) is designed in a structure that is wide at the bottom and narrows at the top. In this way, the suture threads previously placed around the annulus are passed through the thread gaps of the test ring (1.1), the ring is lowered on the valve annulus, and suture threads are passed from the wide lower side of the thread channel (1.3), and the sewing threads are pulled out over the thread channel (1.3) and jammed in the narrowed upper part of the thread channel (1.3).

Thanks to the outward inclination of this thread channel (1.3) and the narrowing channel structure, the sewing threads are pulled outward the thread channel (1.3) is easily squeezed at the end and the sewing threads are kept around the intervened area. The shape of the thread gap (1.2) and the thread channel (1.3) is such that it does not damage the sewing thread. Thanks to the oval narrowing structure of the thread channel (1.3), it is ensured that the sewing threads are not damaged during embedment into the thread channel (1.3) and their subsequent removal.

After the test apparatus (1) is placed as described above, the valve competency test is performed by filling fluid into the ventricle. If the configuration of the leaflets are satisfactory and does not leak the fluid out , it is concluded that the correct size has been selected and the threads in the thread channels (1.3) are pulled inward in the opposite direction of the squeezing and the test apparatus (1) is removed. If the valve competency is not achieved due to the inaccurate size selection, the test apparatus (1) is removed in the same way and a different (a larger or smaller) sized test apparatus (1) is attached and tested as described.

After concluding the appropriate ring size by using the designed test apparatus (1), the same sized prosthetic annuloplasty ring is tied to the mitral or ticuspid valve annulus as usual and the operation is completed.

In current methods, the correct prosthetic ring size selection needs high level experience gained by a considerable volume of patients. Correct sizing of the ring is the key element of mitral and tricuspid valve prosthetic ring annuloplasty operations. Wrong ring size selection extend and complicates the operation process. To attach a ring of another size, the surgeon has to cut the tied stitches of the ring to be removed and pass new sutures through the delicate valve annulus, which has already been damaged due to the previous stitches, and place a new size prosthetic ring. Thanks to the test apparatus (1) for mitral and tricuspid valve prosthetic ring annuloplasty surgeries, in case of a wrong size selection, the subsequent tests for valve competency are completed without damaging the previously placed annulus suture threads, and the accurate prosthetic ring size is easily selected and attached. Thanks to the test apparatus (1) for mitral and tricuspid valve prosthetic ring annuloplasty surgeries, the subject of the invention, it is possible to select the correct size by testing with a test ring (1.1) that is identical in shape and size to the manufactured prosthetic ring to be used. Thanks to the ability to test without knotting and cutting the sewing threads, the area of the delicate annulus tissue where the sutures are passed is not damaged. Since the structure of the thread channel (1.3) is designed in such a way that it does not damage the sewing threads, the test apparatus (1) of different sizes are safely tested.

The detail views of the thread gap (1.2) and the thread channel (1.3), which are the main elements for the test apparatus (1) for mitral and tricuspid valve prosthetic ring annuloplasty surgeries, are tried to be expressed in Figure 1, Figure 2 and Figure 3. In Figure 4, the test apparatus (1) for mitral and tricuspid ring annuloplasty operations is given as a general view, where the possible sequences of the thread gap (1.2) and the thread channel (1.3) configurations around the test ring (1.1) are tried to be expressed. The view of the test ring (1.1) presented in Figure 4 is to provide a perspective and will be configured in accordance with the shape of the prosthetic ring to be used in annuloplasty surgeries. Depending on the technique and guides used, the row and number of the thread gap (1.2) and the thread channel (1.3) can be adjusted according to the order and number to be used for sewing the relevant prosthetic ring.

The subject of the invention is that the test ring (1.1) used for the test apparatus (1) for mitral and tricuspid valve prosthetic ring annuloplasty surgeries will be identical to the shape and size of the prosthetic rings to be used, it can be adapted to the new ring types that will be developed, the number and order of the thread gap (1.2) can be changed, the thread channel’s (1.3) ability to easily grab and release the threads without damaging and it is obvious that different designs can be made around the idea. These are also within the scope of the invention. It is obvious that changes can be made regarding the shape, the parts used can be changed, and the number of used parts can be changed on the invention, regardless of the material and size. All of these are within the scope of the invention. It is clear that a person skilled in the art can introduce the innovation disclosed in the invention by using similar embodiments and / or apply this embodiment to other similar purpose fields used in the related art. Therefore, it is obvious that such structures will lack the criteria for innovation, especially for exceeding the known state of technique.