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Rotary disc prostheses of the heart valve

The composition of the elements of the rotary disk prosthesis of the heart valve.
From left to right :
* disk (locking element);
* housing with large and small travel stops;
* sewing cuff.
A sketch of the aortic prosthesis.
A sketch of the mitral prosthesis.

Rotary-disk prostheses of heart valves belong to the group of axisymmetric mechanical artificial heart valves . Their distinguishing feature was the design of the locking element in the form of a disk mounted pivotally in the cylindrical body of the prosthesis, with the possibility of rotation of the disk around an axis located in the plane of the body.

Due to good hydrodynamic properties, low profile and wear resistance, they were most in demand in the clinical practice of 1970-1980, and the best foreign and domestic models of prostheses of this design are successfully used at present.

Foreign developments

Early Models

The first experience in creating a prosthesis with a locking element in the form of a rotating disk was the Lillehei — Cruz — Kaster model , which develops the idea of ​​a small-sized disk valve by Charles Hafneigel . It was proposed in 1963 by A.V. Cruz , surgeon Clarence Lillechai and engineer of his laboratory RL Kaster , to replace the mitral valve of the heart, giving the disk the shape of a convex-concave meniscus and fulfilling the stroke limiters of the locking element in the form of arched slopes of arches of different heights, forcing the disk does not move parallel to the plane of the base of the prosthesis, but with rotation relative to it [1] .

The Japanese surgeon J. Wada in 1966 developed the Wada — Cutter disc valve, in which the disc rotated on two hinges relative to an axis located in the plane of the body and somewhat diverged from its center [2] [3] . Serial production of these prostheses began in 1967 , and their success is shown by the use of four Wada — Cutter valves in the first artificial heart , created in 1969 by Denton Cooley . Structurally, in the open position of the valve, the locking element in the form of a rigid Teflon disk was held in position at an angle to the blood flow with two metal protrusions of the body. The hinges of the fastening of the locking element were designed so that the voltage from repeated openings and closures of the valve focused on two axial points of rotation of the disk, which led to wear of Teflon in the places of attachment and caused dysfunction of the valves and embolism , which caused the prosthesis to cease production in 1974. However, the good hemodynamics observed during its use stimulated the development of Bjork — Shiley and Lillehey — Kaster prostheses.

Bjork Dentures — Shiley

Swedish surgeon Viking Björk , who headed the surgical department of the Karolinska Institute in Stockholm , used the experience gained in implanting ball prostheses and Wada — Cutter valves to create Russian in 1969 with Donald Shaili (Shiley Laboratories, California ) base model of a rotary disc valve [4] [5] [6] . In a design known as the Bjork — Shiley Standart , the polyformaldehyde disc-shaped locking element was held open between the large and small radiopaque horseshoe-shaped restraints welded to the stellite body. The disk could freely rotate around its axis, distributing wear around the circumference of the supply and exhaust surfaces. It could tip over at an angle of 60 ° with respect to the plane of the prosthesis (when closed, the angle was 0 °). Teflon was chosen as the material for the cuff, and the shape of the cuff was different depending on the position of the implant. The size of the prosthesis on the sewing cuff was 17–33 mm, with a diameter of the hydraulic hole 12–24 mm.

In 1971, a polyformaldehyde disk, which absorbed liquid and changed the volume of the locking element, was replaced with a graphite with a high-temperature carbon coating, and in 1975 an radiopaque ring mark was added to it. After such a modification, the valve became one of the most commonly used mechanical prostheses. However, the welded joint of the wire limiters with the body began to break down in a long time after the operation, which caused the disc to fall out of the body and the patient died [7] [8] .

The goal of creating the next Bjork — Shiley Convexo-Concave model in 1975 was to increase the opening angle of the disc to 70 ° and reduce the turbulence of the blood flow. Its main difference was the use of a convex-concave pyrolytic disk to increase the speed of the prosthesis. The disk was held thanks to the stroke limiters: the large one, which was carried out in one with the case, and the small one, fastened by welding. The latter was in contact with the central recess of the back of the disk.

An increase in the opening angle reduced the stagnation zone behind the disk and contributed to a decrease in thromboembolic complications from 4.2% to 1.2% per year after mitral valve replacement [9] [10] . However, cases of destruction of the valve body continued, and in 1986 it was banned for clinical use [11] . Examinations showed that the breakage of small disk limiters occurred at the place of their welding with the prosthesis body. Subsequently, a program was developed to identify patients with a potential risk of such damage, all patients were recommended careful monitoring, and some prophylactic replacement of the prosthesis [12] .

The problem of mechanical dysfunctions was solved in 1981 with the creation of the next Bjork — Shiley Monostrut model, by refusing welding joints [13] . The prosthesis was partially made of Haynes-25 alloy, eliminating the need for welding and, therefore, the possibility of cracking in the supports. The input limiter retained a horseshoe-shaped shape, and the output limiter, in the form of a single support, held the disk in place by the central recess on its back side. The disk itself was made of high-temperature pyrolytic carbon and had a convex-concave shape.

By their mechanical reliability, Bjork-Shiley prostheses significantly exceeded the best models of ball prostheses , withstanding the increased load corresponding to 27-30 years of work in the human heart.

Bjork — Shiley valves are not currently available.

Lillehei — Kaster dentures

The developers of the Lillehei — Cruz — Kaster prosthesis , realizing its shortcomings, proposed the Lillehei — Kaster model by 1965 . To eliminate the stagnant area behind the disk locking element, RL Kaster brought the axis of rotation of the disk 1/3 of the diameter of the hydraulic hole to the center of the titanium case. The disk travel limiters were significantly reduced in size and moved from the through-hole to the periphery. The disk was held between two stops and could open at an angle of up to 80 ° to the plane of the body, in the closed position this angle was 18 ° (total disk tour - 62 °). All valve components were radiopaque [14] [15] .

Since 1970, polyformaldehyde used to create disks due to its excessive wear was replaced by pyrolytic carbon , the development and research of which was carried out by J. C. Bokros in the framework of this project. Such prostheses still function well in many patients [16] Another Lillehei — Kaster Carbon model was made entirely of pyrolytic carbon . For more than a thirty-year period, the only report of a valve failure of this design is known. [17] .

Omni prostheses

A further development of the Lillehei — Kaster prosthesis was the Omniscience valve, released by Medical CV, Inc. ( Minnesota ) in 1978 [18] [19] [20] . It had the same opening angle (80 °), but was distinguished by a curved disk and short travel stops. The case was made of a solid blank of nickel-free titanium , and the knitted sewing cuff was made of Teflon . The diameter of the valves in the sewing cuff was 19–31 mm, and the diameter of the hydraulic hole for the aortic position was 14.4–24.0 mm, and 14.4–26.0 mm for the mitral one.

Since 1984, the valve was completely made of pyrolytic carbon and was called Omnicarbon . His disk has an x-ray positive label. The diameter of the Teflon sewing cuff is 19–33 mm, and that of the hydraulic hole is 14–24 mm [21] [22] . The valve is currently available.

Medtronic — Hall Prostheses

In 1977, Oslo-based heart surgeon K. V. Hall , his friend A. Woien , who represented Medtronic in Europe, and engineer RL Kaster collaborated with her, proposed a new structural part for butterfly valves. They decided to replace the limiter in the output section of the disk prosthesis with a single support going through the center of the disk, which had a special hole for it. This support, made in the shape of a "goose neck", allows the disk to move freely. The second, smaller stop, stops the movement of the disk when fully open. The prosthesis body is made of titanium , the disk is made of pyrolytic carbon , the cuff for sewing the valve to the fibrous ring is made of knitted Teflon [23] [24] . The prosthesis provides a central blood flow. The opening angle is 70 ° for the mitral position (model M7700) and 75 ° for the aortic (model A7700). The closing angle is 0 °. All valve components are made of radiopaque materials. The body does not have welding units, and the rotating central disk ensures uniform wear of the prosthesis. In the same year, prototypes, called Hall — Kaster , passed clinical trials. Subsequently, Medtronic acquired the rights to manufacture the valve and began to produce it under the name Medtronic — Hall .

The diameters of the sewing cuff of the modern Medtronic — Hall valve are 20–29 mm (for the aortic ) and 23–31 mm (for the mitral position), and the diameters of the hydraulic holes are 16–24 mm and 18–24 mm, respectively. The Medtronic — Hall valve design has not changed since its first clinical use. Today, his body at the request of the surgeon can be rotated relative to the cuff for optimal orientation of the prosthesis directly during the operation.

The Medtronic — Hall prosthesis is characterized by good hemodynamics , sufficient durability, and low thrombogenicity [25] [26] . For 20 years, there were no mechanical failures of this valve model [27] . Medtronic-Hall valves (Models A7700 and M7700) are still approved for clinical use in North America.

AorTech UltraCor prostheses

Since 1984, the clinical application of the rotary disc valve of the heart of AorTech International ( Great Britain ) under the trade name AorTech UltraCor began . Its disk is made of carbon material with the addition of tungsten and a coating of pyrolytic carbon , the case is made of a single titanium billet without welded joints, the cuff is made of knitted Teflon fabric. The opening angle of the aortic valve is 73 °, the mitral is 68 °, and the closing angle is 0 °. The disc and valve body are radiopaque. The prosthesis body rotates relative to the sewing cuff. The diameters of the sewing cuff of the modern AorTech UltraCor valve are 19–29 mm (for the aortic ) and 23–33 mm (for the mitral position). Mechanical valve failures were not noted [28] .

Sorin Biomedica dentures

In foreign Europe, the first manufacturer of rotary disc heart valve prostheses was the Italian company Sorin Biomedica . The prosthesis of the Monocast brand has been used in the clinic from 1977 to the present [29] . In 1986, a carbon-coated sewing cuff was introduced in the Sorin Carbocast model. The year 1988 saw the launch of the Sorin Allcarbon prosthesis, the body of which is made of Carbofilm carbon-coated stellite. Drop-shaped hemodynamic improvers are manufactured using a micro-casting process to prevent material from being unstructured. The graphite locking disc is coated with pyrolytic carbon , and the inside of the sewing Teflon cuff is coated with turbostatic carbon to reduce the risk of tissue proliferation (pannus). The disk contains a radiopaque tantalum wire. The diameter of the sewing cuff is from 19 to 31 mm for the aortic position and 19–33 mm for the mitral position, with diameters of the hydrodynamic opening 14–24 mm. The degree of mobility of the disc is 60 ° from open to closed position. The modification of this valve with one output disc-holding column, by analogy with the Bjork – Shiley Monostrut prosthesis , was called Sorin Monostrut X [30] .

Development in the USSR and Russia

From 1973 to the present, numerous designs of rotary-disk prostheses of heart valves have been developed in the USSR and Russia. The following models were serially produced: LIKS-2 , EMIX, MIX , ELMAK , PLANIX . Currently, in clinical practice, modified models of valves LIKS-2 and MICS are used.

LIKS prostheses

 
Prosthesis LIKS-2
 
The profile of flow rates on the prosthesis LIKS-2

In the USSR, the development of rotary disc valves was started by the employees of the Special Design Bureau of Medical Theme of KCHKhK , which was part of the USSR Ministry of Environment . The Bjork — Shiley valve was adopted as an analog for development. More than 10 experimental models were created, of which LIKS-1 became the most promising (named after the abbreviation of the laboratory and the artificial valve from the heart). As in the foreign sample, when the valve was opened, the locking disk rotated around the stroke limiters by the angle determined by them, shifting along the blood flow, and when closing, it returned and pressed against the inner surface of the cylindrical body. The disk divided the flowing blood stream into two unequal parts: the larger one moved, changing direction, along a line coinciding with the frontal surface of the disk, and the smaller one sought to maintain a rectilinear movement. As a result, the homogeneous flow structure was destroyed and separated flows appeared, leading to an increase in hydraulic resistance and the formation of vortex zones, which contribute to the formation of blood clots in the region of a small hydraulic hole. The presence of a disk travel limiter in this area further increased the risk of thrombosis.

In 1981, the LIKS-2 modification was developed [31] , which is still in demand. A feature of its design was the removal of the stroke limiter of the disk locking element into the region of a larger hydraulic hole from the outlet side of the valve, with the creation of better conditions for flow around the disk. This excluded the formation of stagnant zones in the region of a small hydraulic opening, promoted the maximum preservation of a homogeneous structure of the blood flow and reduced the likelihood of thrombosis . The locking element of the prosthesis is made of isotropic pyrolytic carbon ( carbon- metal), the fine-grained structure of which made it possible to obtain locking elements with a polished surface of high purity. It is made in the form of a convex-concave disk, facing concavity to the stream. The disk profile is chosen so as to ensure the most favorable distribution of shear stresses in the blood stream and the most rapid and complete opening and closing of the valve. The opening angle of the locking element is 70-75 ° (in the closed position 0 °). The design of the disk rotation unit ensured its free rotation around the central axis and uniform wear. The case with disk stroke limiters is made of a single piece of titanium ; a high class of cleanliness of its surfaces is achieved by electrolytic polishing .

Detailed hydrodynamic studies [32] at the stage of development of prostheses made it possible to achieve minimal pressure losses on the valve, maximum throughput, and insignificant backflow. Welding, brazing, casting and other techniques that could cause violations of the initial strength characteristics of the material were excluded from the manufacturing process of its manufacture.

For the sewing cuff, a polyester warp knitted fabric with the porosity necessary for germination during the implantation process is used. Initially, the prosthesis was equipped with a base cuff, which provided the possibility of orientation of the valve during implantation . Since 2004, it has been performed with reduced and supraannular cuffs for aortic and mitral prosthetics, respectively. To rotate the prosthesis and check the functioning of the disc, a rotator was developed to facilitate these actions, and calibrations were created to select the size of the prosthesis, similar in configuration to the external contours of the prostheses.

When testing valves for durability in the laboratories of the ISSKh named after A.N. Bakuleva, Academy of Medical Sciences of the USSR, it was noted that the dynamics of disk wear allows us to guarantee the performance of the prosthesis for over 100 years. LIKS-2 began to be used in cardiac surgery since 1982 [33] . In 1998, for the development and implementation of LIKS-2, a team of engineers and doctors was awarded the Prize of the Council of Ministers of the USSR .

12 sizes of prostheses LIKS-2 are available: six for aortic (20, 22, 24, 26, 28, 30 mm) and mitral (26, 28, 30, 32, 34, 36 mm) positions. [34]

EMIX and MIX prostheses

At the initiative of the director of the Institute of Agriculture A.N. Bakuleva, Academy of Medical Sciences of the USSR V.I. Burakovsky in the second half of the 1970s In addition to the USSR Ministry of Environment, the Ministry of Electronic Industry of the USSR joined the problem of creating prosthetic heart valves. Such work was started in 1979 at the Emitron Electrovacuum Instrument Factory (Moscow), with the participation of the Research Institute of Materials Science ( Zelenograd ) and the NPO Khimvolokno ( Mytishchi ).

The Bjork — Shiley valve was also adopted as an analog for development. For the manufacture of the body of the EMIX prosthesis (named after the abbreviation "electronics - medicine - artificial heart valve"), cobalt - chromium alloy 45KHVN was selected, which is characterized by good thromboresistance, high strength and corrosion resistance. The prosthesis body was made in the form of a ring with two wire limiters soldered into it of circular cross section - brackets (large and small). The use of stamping in the manufacture of the housing increased the reproducibility of the parameters. Soldering was carried out in vacuum by high-frequency currents , which ensured the strength of the connection. A disk of isotropic pyrolytic carbon ( carbon- metal) had a plano-convex shape and opened at 60 °. For the sewing cuff, we used fabric from a base knitted dacron fabric, which quickly implanted with biological tissue after implantation of the prosthesis. The maximum height of the prosthesis in the open position was 14 mm.

The appearance of publications on catastrophic breakdowns of Bjork — Shiley prostheses caused by unreliable welded joints has led to a change in the design and manufacturing technology of the EMIX prosthesis. In the new design, the bracket holding the disk was replaced with an oval-shaped pin, and the prosthesis body with all elements was made monolithic using titanium vacuum smelting, which reduced the mass of the prosthesis. The disk in this model was convex-concave in shape (studies have shown that it has the best characteristics [35] ) and opened up to 60 °, shifting 2 mm downstream, which improves valve washing and eliminates the formation of stagnation zones at the disk contact points and rings [36] .

The experience of using EMIX valves showed high sonicity during their functioning in the body, which made prostheses socially unacceptable for some patients. To reduce the noise of the work, Professor N. A. Iophis for the first time in the world proposed introducing an acoustic gap into the large arch of the prosthesis. This idea was embodied in the EMIX-N model. Subsequently, for a better blood flow, EMIX-DV models with a biconcave disc and EMIX-NDV were developed, combining the advantages of an open bracket and a biconcave disk [37] .

Serial production of EMIX valves was started in 1983, for the aortic position there were three landing prosthesis sizes: 21, 23, 25 mm, for the mitral one - four: 25, 27, 29, 31 mm. Cuffs for various positions were individual, with the possibility of rotation of the valve relative to the cuff for precise orientation of the prosthesis. Subsequently, the efforts of the Central Research Institute of the Cotton Industry (Moscow), the Institute of Chemical Physics and the Vitebsk Institute of Technology created an unmatched thromboresistant carbon fabric and vitlan threads for cuffs of prosthetic heart valves.

Since 1991, the same development team began to create a new model of rotary disc valves in the Rosinvest LLP that they founded in Moscow, and in 1996 reorganized into Roskardioinvest LLC. The new model, called MICS (“Moscow artificial heart valve”), retained and developed the design features of the EMIX model: it had an opening angle increased to 72 °, a low noise level due to the acoustic gap of the bracket, and the high reliability provided by the body material — titanium of a special microstructure and purity, and its monolithic execution, which eliminated the appearance of internal stresses.

The opening and closing times of the locking element - a convex-concave disk made of isotropic pyrolytic carbon ( carbon- metal) - were no more than 0.04 s and 0.025 s, respectively.

For the cuff, the warp knitted carbon fabric Vitlan was used. Subsequently, models with a cuff made of polyester yarns were developed: MIX-1 with open and MIX-2 with a closed bracket.

10 sizes of prostheses MICS are produced: five for aortic (19, 21, 23, 25, 29, 29 mm) and mitral (23, 25, 27, 29, 31 mm) positions. [38]

ELMAK prostheses

At the end of the 1980s, at the Moscow NPO ELMA, the ELMAK prosthesis [39] , an improved version of the Lillehei-Kaster prosthesis design, was developed and introduced into the clinic since 1990. In this model, the output disk limiters were made in the form of lateral protrusions of the prosthesis body, the input limiters consisted of two cantilevered protrusions and a side along the input surface of the prosthesis body. Entrance and exit limiters practically did not fall into the lumen of the passage openings of the prosthesis.

Such a design made it possible to abandon the notch on the convex surface of an equal - thickness convex-concave disk, which made it possible to almost halve its mass and reduce its inertia. In the closed state, the disk lies at an angle of 12 ° to the plane of the prosthesis, its opening angle for the mitral position was 68 °, and for the aortic position - 75 °. Compared with the LIKS-2 and EMIX prostheses, the volume of reverse leaks on the ELMAK prosthesis was 50% less, the opening and closing times of the disc were 10-15% less. However, in clinical practice, frequent cases of prosthetic thrombosis were noted, and therefore its use was discontinued.

PLANIX prostheses

In 1988, the Belarusian Electronmash plant, part of the NPO PLANAR, began developing a prosthesis that has been commercially available under the brand name PLANIX since 1992 for implantation in the mitral and aortic positions [40] .

The prosthesis body is made of a single piece of titanium , has two hinges with restrictive shields for fixing the locking element and four small disk travel stops. On the inner surface of the body there is a groove in which the disk rests when the valve is closed. The locking element is made of isotropic pyrolytic carbon ( carbon- metal) in the form of a convex-concave disk. Opening angles of the disc: in mitral prostheses - 68 °, aortic prostheses - 73 °. The general configuration of the prosthesis, the absence of elements protruding into the lumen of the prosthesis (like Omniscience valves) made it possible to increase its throughput, reduce flow turbulence , reduce the pressure gradient and the volume of back leak. The sewn-in cuff of the PLANIX valve is made of polyester fabric such as velor and allows the prosthesis body to be rotated inside it. Contrasting marks are applied on it for convenience of valve orientation during implantation [41] .

10 standard sizes of PLANIX prostheses are produced: five for aortic (19, 21, 23, 25, 27, 27 mm) and mitral (23, 25, 27, 29, 31 mm) positions.

Overview of copyright certificates and patents

Improving the design of rotary-disk prostheses of heart valves took the path of increasing their reliability. For this purpose, the valve body was made of titanium , and the locking element was made of isotropic pyrolytic carbon ( carbon dioxide ) [42] . The increased denture service life ensured uniform wear of the locking element by rotating it around the central axis. This was achieved by making the jumper of the disk rotation limiter in the form of two curved sections and placing it at an angle to the plane of the axis of the rod of the second limiter [43] . For the same purpose, a valve was designed with spinning of the disk during its movement in the blood stream, which was achieved by creating a one-sided bevel of the output surface of the disk from the center to the periphery [44] , or by making one of the limiting protrusions with a bevel towards the center of the valve [45] , or displacement of the protrusions relative to each other in the direction of rotation of the disk [46] .

High wear resistance was ensured by the distribution of loads on valve elements, for which one of the disk limiters was performed with supporting surfaces [47] . To reduce the wear of the locking element, the disk was equipped with an annular bead concentrically located on its outlet surface [48] .

To prevent jamming of the disk, safety elements of the turning means located on the surface of the locking element facing the reverse blood flow were proposed [49] . To reduce the valve resistance, the disk was made with a kink along the axis of rotation [50] , an elastic arcuate element was installed on the valve seat, and a cylindrical protrusion was performed on the disk [51] .

The reduction of thrombosis and hemolysis was ensured by the fact that the disk limiter located in the smaller passage opening was connected to the housing from the side of the larger passage opening. [31] To improve the hydrodynamic characteristics of the prosthesis, the locking element was installed in the disk holder and guide protrusions so that parts of the passage opening were displaced relative to its diametrical plane in opposite directions from the axis of rotation of the disk [52] . To reduce thrombosis, it was proposed to swirl the blood flow with a disk with spiral guides [53] or by making radial grooves [54] and faces [55] on the output surface of the disk.

In total, from 1973 to 2006, 34 designs of domestic rotary-disc prostheses of heart valves were protected by copyright certificates of the USSR and RF patents . Of all the proposed modifications, LIKS-2 , EMIX and MICS are of primary importance for clinical practice.

Clinical practice

Operation Technique

The design features of rotary disc valves required the development of a new implantation technique with a clear orientation of the prosthesis in both the mitral and aortic positions [56]. When preparing the prosthesis for implantation and during it, it was recommended to use the holders with which the prostheses were equipped, in order to avoid deformations of the locking stroke limiters element and touches by metal tools of the frame and disk elements to exclude the formation of roughnesses on the polished surface of the prosthesis, which are inevitable but will cause thrombus formation.

For the mitral position, the dependence of the hydrodynamics of the flow in the left ventricle on the orientation of the prosthesis was studied in the polymer laboratory of the ISSKh im. A.N. Bakuleva, USSR Academy of Medical Sciences . The study showed that the diastole flow is circular with vortex zones in the center of the ventricle, behind the disc and in the area of ​​muscle stumps . By the beginning of systole , reorientation of streamlines to the excretory tract of the left ventricle occurs, which is associated with the formation of foci of turbulence and loss of energy. The only orientation of disk prostheses in which the flow enters the excretory tract of the left ventricle without changing direction is when the disc opens toward the posterior external wall of the ventricle opposite the excretory tract [57] . However, in practice, if it is not possible to choose the optimal orientation of the prosthesis due to anatomical features, the surgeon implants it in such a way as to ensure unhindered movement of the locking element [58] . Taking into account the peculiarities of hydrodynamics during prosthetics of the aortic valve, its larger half-opening should be oriented towards the non-coronary valve.

Transsternal access has become the most common, although with isolated mitral valve replacement, right-sided anterolateral thoracotomy is also used [59] . Access to the aortic valve is through a transverse aortotomy or through a transverse oblique aortic incision. Mitral valve prosthetics can also be performed by access through the left atrium after atrial fissure or through the right atrium and atrial septum. The valve flaps are excised with a margin of 1-2 mm. Since the free movement of the disc is one of the main factors in the optimal functioning of prostheses with a rotary locking element, it is necessary to carefully form the prosthesis bed, excise subvalvular structures and remove foci of calcification as much as possible [60] [61] .

A variety of sizes of rotary-disk prostheses allows you to select them depending on the parameters of the fibrous ring and heart chambers. The required prosthesis size is set using special meters. At the same time, some authors suggested taking the size of the prosthesis one number less than the corresponding caliber of the fibrous ring, taking into account cardiac relaxation [62] . U-shaped sutures are mainly used to fix the prosthesis, but other options are also recognized: continuous suture, nodular, intermittent 8-shaped. The use of Teflon gaskets is advisable in patients with a thin or damaged fibrous ring.

Clinical Results

By 1991, the Russian Union of Artists named after A.N. Bakuleva, the Academy of Medical Sciences of the USSR, had the greatest experience in using prostheses LIKS-2 and EMIX for prosthetics of heart valves (1035 patients). Based on this material, it was concluded that by the 7th year after surgery, the survival rate after mitral valve replacement was 88.1 ± 0.71%, of the aortic - 87.0 ± 0.62%; in the group of mitral-aortic prosthetics - 80.2 ± 0.84%. By 1995, in the NTSSSH them. A.N. Bakuleva RAMS has already performed 2911 operations, while about 4000 prostheses LIKS-2 and EMIX were implanted. With a significant reduction in hospital mortality (single-valve prosthetics - 3.5%, mitral-aortic - 6.5%), patients by the 12th year after surgery were 88% with single-valve and 82% with mitral-aortic prosthetics [58] [59 ] [59 ] ] .

Analysis of the immediate and long-term results of the clinical use of the LIKS-2 and EMIX prostheses showed high patient survival and the stability of good results. The frequency of specific prosthetic complications after implantation of rotary disc valves was significantly lower than when using ball prostheses. When analyzing long-term results in 1349 patients, G. I. Zuckerman noted prosthetic thrombosis in 4 patients [63] . According to G. G. Khubulava, the incidence of prosthesis thrombosis was 0.3% in patients with a mitral or aortic valve prosthesis and 1.6% of the tricuspid valve [64] . According to the results of the clinical use of LIKS-2, cited by B. A. Konstantinov, out of 33 patients who underwent mitral valve replacement, prosthesis thrombosis occurred in one patient [33] . By the 7th year after surgery, 88.7% of patients in the mitral observation group, 96.9% in the aortic group, and 88.3% in the mitral-aortic group were free from thromboembolic complications [65] . The second most common observation among specific complications, all authors noted prosthetic endocarditis . Rare cases of para-prosthetic fistulas and single prosthetic dysfunctions are also described.

Reoperations after implantation of prostheses accounted for 3-8% of all interventions on the heart valves [66] . The reasons for the reoperations were: prosthetic infectious endocarditis 54.5%, prosthetic fistula 34.6%, jamming of the disc 9.1%. Reactions in connection with prosthetic thrombosis according to M. A. Pajeev were performed in 25 patients out of 2420 patients [67] . The technique for performing these operations had its own characteristics: all interventions were performed from mid-access. With prosthetic endocarditis, after excision of the prosthesis, the fibrous ring and surrounding structures were carefully treated with antiseptic solutions. In all cases of replacement of the prosthesis, the new prosthesis was fixed with U-shaped seams on Teflon gaskets.

Advantages and disadvantages of rotary disc valves

By their mechanical qualities (mechanical reliability, durability of operation), clinical options for disc prostheses are superior to ball and small - sized constructions [68] .

Prostheses of this type have good hemodynamic characteristics, approaching those of a natural valve . Blood injury occurs within acceptable limits and is adjusted medically. When a patient maintains a given level of anticoagulant therapy, the risk of thrombosis and thromboembolic complications is a few percent.

The disk has the ability to rotate and change contact points with seat stoppers, which reduces the risk of material wear. The durability of these prostheses is more than sufficient to confidently predict normal function in real-time patient life regardless of age. Low profile is the main advantage of disk prostheses: their height in the closed state does not exceed 7 mm (for ball joints - 20 mm or more).

 
Assessment of prostheses for the presence of zones dangerous for thrombosis.
Model fluid - milk 6% fat. Places of deposition of milk elements are the most dangerous. Running hours - 2 hours at a frequency of 60 bpm. Left prosthesis Bjork — Shiley , right LIKS-2

At the same time, this design has several disadvantages that are potentially dangerous and affect clinical results. Due to the displacement of the axis of rotation of the disk, the valve, when opened, has two through holes - large and small. The presence of turbulent blood flow in the small opening and stagnant zones behind the valve seat in cases where anticoagulant administration is impossible, leads not only to thromboembolism , but also to thrombosis , and prosthetic thrombosis in this zone and gradual stratification of the connective tissue lead to jamming of the disk, catastrophic dysfunction valve and sudden death of patients against pulmonary edema . There is an anatomical mismatch between the mitral valve prostheses due to the large “outflow” of the disc from the valve body. Under clinical conditions, a structurally predetermined opening angle of the disc of 60–80 ° is not really realized, especially with tachyarrhythmias , which leads to an increase in the stenosis of the prosthesis [69] . For many patients, the level of noise caused by impacts of the locking element remains socially unacceptable.

Thus, the creation of prostheses with a rotary disk mechanism made it possible to reduce their size and improve hemodynamic characteristics. However, the main problem of all mechanical valve prostheses, namely the relatively high risk of thromboembolic complications and the need for patients to receive anticoagulants for life, has not been resolved. Therefore, further development of the design of prosthetic heart valves was aimed at minimizing resistance and better thrombotic resistance.

Notes

  1. ↑ Cruz A.V., Kaster RL, Simmons RL et al. A new caged meniscus prosthetic heart valve // ​​Surgery. - 1965. - Vol. 58. No. 5. - P. 995—998.
  2. ↑ Wada J., Komatsu S., Ikeda K. et al. A new hingeless valve // ​​In: Prosthetic heart valves (Brewer LA ed.). - Spring, ill., Charles C. Thomas, Publisher, 1969. - P. 304-314.
  3. ↑ Hallmar GL, Okies JK, Mesamer BJ et al. Long-term results after valve replacement with Wada — Cutter prosthesis. Long-term Prognosis following valve replacement // Adv. Cardiol. (Karger, Basel). - 1972. - Vol. 7, No. 1. - P. 79-86.
  4. ↑ Bjork VO A new tilting disc valve prosthesis // Scand. J. Thorac. Cardiovasc. Surg. - 1969. - Vol. 3, No. 1. - P. 1-10.
  5. ↑ Bjork VO Aortic valve replacement with Bjork — Shiley tilting disc valve prosthesis // Brit. Heart J. - 1971. - Vol. 33, No. 1. - P. 42–46.
  6. ↑ Bjork VO The history of the Bjork — Shiley tilting disc valve // ​​Med. Instrum. - 1977. - Vol. 11, No. 2. - P. 80-83.
  7. ↑ Garsia del Castillo N., Larroifsse-Perez E., Murta-Ferre M. et al. Strut flacture and disc embolization of a Bjork — Shiley mitral valve prosthesis // Am. J. Cardiol. - 1985. - Vol. 55, No. 3. - P. 597-599.
  8. ↑ Lindblom D., Bjork VO, Semb BK N. Mechanical failure of the Bjork — Shiley valve. Incidence, clinical presentation and management // J. Thorac. Cardiovasc. Surg. - 1986. - Vol. 92, No. 37. - P. 894–911.
  9. ↑ Bjork VO, Henze A. Ten year` experience with the Bjork — Shiley tilting disc valve // ​​J. Thorac. Cardiovasc. Surg. - 1979. - Vol. 78, No. 2. - P. 331—342.
  10. ↑ Cortina JM, Martinell J., Artiz V. at al. Comparative clinical results with Omniscience (STM1), Medtronic — Hall, and Bjork — Shiley convexo-concave (70 degrees) prostheses in mitral valve replacement // J. Thorac. Cardiovasc. Surg. - 1986. - Vol. 91, No. 1. - P. 174-182.
  11. ↑ Ostermeyer J., Horstkotte D., Bennet J. et al. The Bjork — Shiley 70 degrees convexo-concave prosthesis strut flacture ptoblem (present state of information // J. Thorac. Cardiovasc. Surg. - 1987. - Vol. 35, No. 1. - P. 71-72.
  12. ↑ Birkmeyer JD, Marrin CAS, O`Connor GT Should patients with Bjork — Shiley valves undergo prophylactic replacement? // Lancet. - 1992. - Vol. 340, No. 3. - P. 520-523.
  13. ↑ Bjork VO, Lindblom D. The Monostrut Bjork — Shiley heart valve // ​​J. Am. Coll. Cardiol. - 1985. - Vol. 6, No. 4. - P. 1142–1148.
  14. ↑ Gibson TC, Starck PJ, Moos S. et al. Echocardiographic and phonocardiographic characteristics of the Lillehei — Kaster mitral valve prosthesis // Circulation. - 1974. - Vol. 49 No. 3. - P. 434-440.
  15. ↑ Lillehei C. W., Kaster RL, Coleman M. et al. Heart-valve replacement with Lillehei — Kaster pivoting disc prosthesis // NY State Med. J. - 1974. - Vol. 74, No. 7. - P. 1426-1438.
  16. ↑ Olesen KH, Rygg IH, Wennevold A. et al. Aortic valve replacement with Lillehei — Kaster prosthesis in 262 patients: an assessment after 9 to 17 years // Eur. Heart J. - 1991. - Vol. 12, No. 6. - P. 680-689.
  17. ↑ Stewart S., Cianciotta D., Hicks GL et al. The Lillehei — Kaster aortic valve prosthesis. Long-term results in 273 patients with 1253 patient-year of follow-up // J. Thorac. Cardiovasc. Surg. - 1998. - Vol. 95, No. 6. - P. 1023-1030.
  18. ↑ Carrier M., Martineau JP, Bonan R. et al. Clinical and hemodynamic assessment of the Omniscience prosthetic heart valve // ​​J. Thorac. Cardiovasc. Surg. - 1987. - Vol. 93, No. 2. - P. 300-304.
  19. ↑ Mikhail AA, Ellis R., Johnson S. Eighteen-year evolution the Lillehei — Kaster valve to the Omni design // An. Thorac. Surg. - 1989. - Vol. 48, No. 1. - P. 61-68.
  20. ↑ Edwards MS, Russell GB et al. Results of valve replacement with Omniscience mechanical prostheses // An. Thorac. Surg. - 2002. - Vol. 74, No. 3. - P. 665-670.
  21. ↑ Thevenet A., Albat B. Long-term follow up of 292 patients after valve replacement with Omnicarbon prosthetic valve // ​​J. Heart valve Dis. - 1995. - Vol. 4, No. 5. - P. 634-639.
  22. ↑ Abe T., Kamata K., Kuwaki K. et al. Ten years` experience of aortic valve replacement with the Omnicarbon valve prosthesis // An. Thorac. Surg. - 1996. - Vol. 51, No. 5. - P. 1182-1187.
  23. ↑ Hall K. V., Kaster RL, Woien A. An improved pivotal disk-type prosthetic heart valve // ​​J. Oslo City Hosp. - 1979. - Vol. 29, No. 1. - P. 3-6.
  24. ↑ Butchart E. G. Early clinical and hemodynamic results with Hall — Kaster valve in Medtronic International Valve Symposium // Lisbon, Portugal, Congress Books - 1981. - P. 159
  25. ↑ Nitter-Hauge S., Abdelnoor M., Svennevig JL Fifteen-year experience with the Medtronic — Hall valve prosthesis. A follow-up study of 1104 consecutive patients // Circulation. - 1996. - Vol. 94, No. 10. - P. 1105-1108.
  26. ↑ Keenan RJ, Armitage JM, Trento A. et al. Clinical experience with the Medtronic — Hall valve prosthesis // An. Thorac. Surg. - 1990. - Vol. 50, No. 4. - P. 748-752.
  27. ↑ Butchart EG, Li HH, Payne N. et al. Twenty years` experience with the Medtronic — Hall valve // ​​J. Thorac. Cardiovasc. Surg. - 2001. - Vol. 121, No. 4. - P. 1090-1100.
  28. ↑ Li HH, Jeffrey RR, Davidson KG et al. The Ultracor tilting disc heart valve prosthesis: a seven-year study // J. Heart Vave Dis. - 1998. - Vol. 7, No. 3. - P. 647–654.
  29. ↑ Hurle A., Abad C., Feijoo J. at al. Long-term clinical performance of Sorin tilting-disc mechanical prostheses in the mitral and aortic position // J. Cardiovasc. Surg. (Torino). - 1997. - Vol. 38, No. 4. - P. 507-512.
  30. ↑ Milano A., Bortolotti U., Mazzucco A. at al. Heart valve replacement with the Sorin tilting-disc prosthesis. A 10-year experience // J. Thorac. Cardiovasc. Surg. - 1992. - Vol. 103, No. 2. - P. 267-275.
  31. ↑ 1 2 Gorshkov Yu. V., Evdokimov S.V., Kartoshkin V.M., Perimov Yu.A. et al. Artificial heart valve: Auth. St. No. 1035867, declared 07/09/1981, publ. 02/27/1984 // Bull. fig. 1984 No. 8.
  32. ↑ Evdokimov S.V. Studies of the hydrodynamic characteristics of artificial heart valves of various designs in laboratory conditions: Author. dis. ... cand. tech. Sciences - L., 1980 .-- 23 p.
  33. ↑ 1 2 Results of laboratory and clinical trials of new domestic heart valves of the LIKS-2 model / Konstantinov B.A., Kartoshkin V.M., Evdokimov S.V. et al. // Grudn. surgery. - 1989. - No. 2. - S. 12-17.
  34. ↑ Boqueria, 2012 , p. 25.
  35. ↑ Small-sized disk artificial heart valves / Agafonov A.V., Zaretsky Yu.V., Kevorkova R.A. // Electron. industry. - 1984. - Vol. 138 - No. 10. - S. 89-91.
  36. ↑ Manukyan V.E. Clinical and hemodynamic results of replacing the mitral valve with low-profile prostheses with a folding locking element: Abstract. dis. ... cand. honey. Sciences - M., 1987. - 23 p.
  37. ↑ Artificial heart valves EMIX / Bukatov A.S., Iofis N.A., Kevorkova R.A. // Honey. equipment. - 1987. - No. 5. - S. 55-56.
  38. ↑ Boqueria, 2012 , p. thirty.
  39. ↑ New artificial heart valve ELMAK / Faminsky D.O., Fadeev A.A., Agafonov A.V. et al. // Thoracic and cardiovascular chir. - 1994. - No. 5. - S. 30—33.
  40. ↑ Five-year experience of using PLANIX prostheses for surgical correction of acquired heart defects / Ostrovsky Yu. P., Skornyakov V.I., Chesnov Yu.M. et al. // Thoracic and cardiovascular chir. - 1998. - No. 2. - P. 28—32.
  41. ↑ Ostrovsky Yu. P. Development and clinical use of valve prostheses “PLANIX” in the surgery of heart defects: Abstract. dis. ... doctor. honey. Sciences - Mn., 1996. - 38 p.
  42. ↑ Kuzmichyov G.P., Dobrova N. B., Grigoryev A.M. Artificial heart valve: Aut. St. No. 1832465, declared 02/18/1988, publ. 12/10/1995 // Bull. fig. 1995 No. 34.
  43. ↑ Iophis N.A., Wetzel R.N., Bukatov A.S. Prosthesis of the heart valve: Auth. St. No. 1082425, declared 06/21/1983, publ. 03/30/1984 // Bull. fig. 1984 No. 12.
  44. ↑ Bukatov A.S., Agafonov A.A., Kostretsov S.V. Prosthesis of the heart valve: Auth. St. No. 1553110, declared 05/25/1987, publ. 03/30/1990 // Bull. fig. 1990 No. 12.
  45. ↑ Kuzmichev G.P., Grigoryev A.M., Yanovich I.P. et al. Artificial heart valve: Auth. St. No. 2025111, declared 07/03/1989, publ. 12/30/1994 // Bull. fig. 1994 No. 24.
  46. ↑ Kuzmichyov G.P., Yanovich I.P., Grigoryev A.M. Artificial heart valve: Aut. St. No. 2072236, declared 05/12/1988, publ. 01/27/1997 // Bull. fig. 1997 No. 3.
  47. ↑ Konstantinov B.A., Gorshkov Yu.V., Evdokimov S.V. Prosthesis of the heart valve: Auth. St. No. 1761132, declared 05/04/1987, publ. 09/15/1992 // Bull. fig. 1992 No. 4.
  48. ↑ Evdokimov S.V., Melnikov A.P., Gorshkov Yu.V., Prosthesis of the heart valve: Auth. St. No. 1808320, declared 07/15/1988, publ. 04/15/1993 // Bull. fig. 1993 No. 14.
  49. ↑ Gorshkov Yu. V., Vdovin V.Z., Novikov A.I. Prosthesis of the heart valve: RF Patent No. 2297200, filed July 11, 2005, publ. 04/20/2007 // Bull. fig. 2007 No. 11.
  50. ↑ Lakshin M.A., Druzhdin Yu.P. Artificial heart valve: Auth. St. No. 438415, declared 01/02/1973, publ. 08/05/1974 // Bull. fig. 1974 No. 29
  51. ↑ Yakovenko V.S., Postalyuk N.I. Artificial heart valve: Auth. St. No. 843978 stated 05/03/1979, publ. 07/07/1981 // Bull. fig. 1981 No. 25
  52. ↑ '' Kuzmichyov G.P., Yanovich I.P., Grigoryev A.M. Prosthesis of the heart valve: RF Patent No. 2068667, filed 12/25/1989, publ. 11/10/1996 // Bull. fig. 1996 No. 31.
  53. ↑ Zakharov V.N., Gunin A.G. Prosthesis of the heart valve: Auth. St. No. 1475649, declared 08/20/1987, publ. 04/30/1989 // Bull. fig. 1989 No. 16
  54. ↑ Bukatov A.S., Iofis N.A., Shumakov V.I. Prosthesis of the heart valve: Auth. St. No. 1637785, declared 04/12/1988, publ. 03/30/1991 // Bull. fig. 1991 No. 12.
  55. ↑ Bukatov A.S., Popov L.L., Karateeva I.V. Prosthesis of the heart valve: Auth. St. No. 1637786, declared 04/12/1988, publ. 03/30/1991 // Bull. fig. 1991 No. 12.
  56. ↑ Khurtsilava S.G. Surgical correction of complicated acquired heart defects, methods of using a new, domestic, low-profile disk artificial valve: Abstract. dis. ... Dr. honey. Sciences - M., 1986. - 39 p.
  57. ↑ The choice of the optimal orientation for mitral folding disc prostheses / Semenovsky M.L., Manukyan V.E., Chastukhin V.V. et al. // Grudn. surgery. - 1987. - No. 6. - S. 27-30.
  58. ↑ 1 2 Faminsky D. O. Prostheses EMIX and LIKS in valvular heart surgery: Abstract. dis. ... Dr. honey. Sciences - M., 1991. - 39 p.
  59. ↑ 1 2 Bykov V.I. Surgical treatment of aortic and mitral heart diseases using disk prostheses EMIX and LIKS: Abstract. dis. ... cand. honey. Sciences - St. Petersburg, 1994 .-- 22 p.
  60. ↑ New EMIX disk valve with isolated mitral valve replacement / Burakovsky V.I., Iofis N.A., Shumakov V.I. et al. // Grudn. surgery. - 1986. - No. 1. - S. 10-14.
  61. ↑ Causes and prevention of jamming of the prosthetic heart valve EMIX / Kaidash A.N., Iofis N.A., Khurtsilava S.G. // Grudn. surgery. - 1986. - No. 1. - S. 15-18.
  62. ↑ The use of domestic disk prostheses EMIX and LIKS in the clinic / Iskrenko A.V., Tarichko Yu.V., Konstantinov B.A. // Surgery. - 1987. - No. 6. - S. 18-22.
  63. ↑ Twelve-year experience with the use of EMIX and LIKS prostheses / Zuckerman G.I., Faminsky D.O., Mvlashenkov A.I. et al. // Grudn. and heart-vessel. surgery. - 1996. - No. 6. - S. 39.
  64. ↑ Long-term results of using mechanical prostheses / Khubilava G.G., Shikhverdiev N.E., Marchenkov S.P. // Bull. NTSSSH them. A.N. Bakuleva RAMS. - 2004. - T. 5 - No. 11 (Appendix). - S. 34.
  65. ↑ The experience of using domestic disk prostheses EMIX and LIKS / Zuckerman G.I., Faminsky D.O., Fomina N.G. // Grudn. surgery. - 1991. - No. 5. - S. 6-10.
  66. ↑ Reactions in patients with prostheses EMIX and LIKS / Zuckerman G.I., Faminsky D.O., Narsia B.E. // Grudn. surgery. - 1991. - No. 1. - S. 22-25.
  67. ↑ Thrombosis of rotary-disk prostheses in the mitral position / Khadzheev M.A., Faminsky D.O., Farulova I.O. // Grudn. and heart-vessel. surgery. - 1997. - No. 2. - S. 54–55.
  68. ↑ Clark RE, Clark B. The clinical life history of prosthetic heart valves // J. Cardiovasc. Surg. (Torino). - 1981. - Vol. 22, No. 2. - P. 441–443.
  69. ↑ Dzemeshkevich S.L., Stevenson L.W. Mitral valve diseases. Function, diagnosis, treatment .. - M .: GEOTAR-Media, 2000. - 288 p. - ISBN 5-9231-0029-0 .

Literature

  • Verbova T.A., Gritsenko V.V., Glossy S.P., Davydenko V.V., Belevitin A.B., Svistov A.S., Evdokimov S.V., Nikiforov V.S. Domestic mechanical prostheses heart valves (past and present creation and clinical use). - St. Petersburg: Nauka, 2011 .-- S. 109-128. - 195 p. - 1000 copies. - ISBN 978-5-02-025450-3 .
  • Orlovsky P.I., Gritsenko V.V., Yukhnev A.D., Evdokimov S.V., Gavrilenkov V.I. Artificial heart valves. - St. Petersburg: OLMA Media Group, 2007. - S. 64–72, 91–98. - 448 p. - 1,500 copies - ISBN 978-5-373-00314-8 .
  • Bockeria L.A., Fadeev A.A., Makhachev O.A., Melnikov A.P., Bondarenko I.V. Mechanical prostheses of heart valves. Reference manual. - M .: NTSSSH im. A.N. Bakuleva RAMS, 2012 .-- 141 p. - 500 copies. - ISBN 978-5-7982-0306-2 .
Source - https://ru.wikipedia.org/w/index.php?title=Rotary-disk_oprostheses of the heart_valve&oldid = 100410090


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