RU2514726C1 - Cryosurgical epicaridal applicator - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely to cardiosurgery, and may be applied for myocardial cryoablation in treating auricular fibrillation. A cryosurgical epicardial applicator comprises a cylindrical core 1 made of porous titanium nickelide axially mounted on a wire rack 2 made of titanium nickelide. The core is provided with a long flange in the form of a crest 3 and curved smoothly lengthwise at an angle of 20-30 degrees together in a plane orthogonal to a radial direction of the crest to provide a contact with epicardial tissues on the extended region of the cryoexposure.

EFFECT: provided adaption of the device for cryodestruction of the myocardial segments and reducing a procedure length included in a total time of anaesthetising the patient.

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Description

The invention relates to medicine, namely to cardiac surgery, and can be used for cryoablation of the myocardium from the epicardium in the treatment of atrial fibrillation (AF).

Atrial fibrillation is associated with a violation of the order of distribution of nervous excitation in the myocardium of the atria, when closed re-entry pathways form among the ramified system of nerve fibers. One of the areas of cardiac surgery is the surgical treatment of AF, which is resorted to if the possibilities of drug therapy are exhausted.

The fight against AF is one of the most important tasks of modern medicine. This pathology occurs in the general population with a frequency of 0.4-1.0%, being one of the most common types of arrhythmias [1].

Atrial fibrillation is associated with a third of all hospitalizations for cardiac arrhythmias [2].

The number of people with AF is constantly growing. The reasons for this growth are diverse: an increase in the proportion of elderly people in society, an improvement in the diagnosis of AF at the outpatient stage, an increase in the number of survivors after acute myocardial infarction, etc. [3].

AF refers to life-threatening complications due to the formation of blood clots, which lead to the development of ischemic stroke in patients with AF five times more often than among people without AF [4].

The result of the action of AF on intracardiac hemodynamics is a gradual dilatation of the heart chambers with a subsequent decrease in the contractile function of the ventricular myocardium (arrhythmogenic cardiomyopathy) [5].

Besides the fact that AF shortens life expectancy, it also negatively affects the quality of life [6].

Given the complexity and importance of the problem for various indications, various methods of treating AF are used, such as drug treatment, pacemaker, transvenous catheter radiofrequency ablation, and including surgical methods [7].

Existing treatments for AF are aimed at the destruction of multiple rings of recirculation of nervous excitation (re-entry), formed in the myocardium of the atria. In this case, various methods of tissue destruction are used: from mechanical dissection to exposure to various physical means: ultrasonic, radio frequency, microwave, laser and cryogenic. They are carried out, as a rule, in combination with other operations on the heart in cardiopulmonary bypass.

In modern cardiology, two main methods of surgical treatment of atrial fibrillation are used. The first method of surgical treatment is based on the creation of a so-called “corridor” of pathways between the first pacemaker - the sinusatrial node and the second-level rhythm driver - the atrioventricular node. At the same time, the cells of the atrioventricular node are isolated from the rest of the atrial tissue, and this, in turn, helps to create a more regular heart rhythm.

The second method of surgical treatment of atrial fibrillation is the maze procedure. The basis of this method is the application of linear damage to the myocardium of both atria in many places to prevent the occurrence of stable re-entry recirculation waves.

Various methods are used to interrupt the pathological pathway of nerve excitation: the “incision-suture” technique, hyperthermic (radiofrequency or ultrasound exposure, laser), hypothermic (cryoablation). The promise of the effect of low temperatures on the myocardium in the treatment of AF patients is due to the fact that cryoablation from the epicardium allows transmural myocardial damage without penetration into the atrial cavity. The cryodestruction zone has, as a rule, regular and clearly defined boundaries, which hinders the further formation of new types of arrhythmias [8, 9].

Thus, among surgical instruments for tissue destruction, an important place belongs to cryo-instruments, which is due to the adequacy of cryotherapy according to the above indicators of transmural exposure and nonarrhythmogenicity.

Currently, there are a number of approaches to achieving cooling and cryodestruction of target tissue and organ sites.

Along with hose and filling systems, which ensure constant flow of refrigerant through a contact instrument for cooling the myocardium (using argon, liquid nitrogen, carbon dioxide), autonomous instruments with porous working parts, in which recruitment and gradual evaporation are performed, play a special role in various areas of surgery coolant. A cryosurgical applicator [10, 11] is known, for example, containing a cylindrical core made of porous titanium nickelide mounted on a wire holder made of titanium nickelide. The cryoapplicator core is a volume formed by interconnected pores. The refrigerant is held in the pores by surface tension.

Known types of cryoapplicators mainly provide exposure pointwise (end surface) [10] or in area (roller) [12]. Meanwhile, in the formation of limited transmission routes of nerve excitation according to the type of “corridor” or “labyrinth”, it is preferable to create not point and not areal, but narrow extended (curvilinear) areas of cryodestruction.

As the closest analogue, the cryosurgical applicator was selected according to the patent of the Russian Federation No. 2221515 dated January 20, 2004 “A device for the surgical treatment of tracheal stenosis”, authors: Dambaev G.Ts., Sokolovich EG, Gunter V.E., Proskurin A.V. ., Fatyushin M.Yu., containing a cylindrical core made of porous titanium nickelide axially mounted on a wire holder made of titanium nickelide. The holder of titanium nickelide, due to its inherent superelasticity, allows you to adjust its bend according to the conditions of bringing to the impact area, which somewhat expands the positioning capabilities during intracavitary operations.

The disadvantage of this device is its non-adaptation for conducting the trajectory of cryodestruction of myocardial tissue during surgical treatment of atrial fibrillation. Due to this drawback, the use of the known device would be associated with a long duration of the procedure, which is undesirable. The procedure time included in the total time spent under anesthesia should be minimal, since it is directly related to a decrease in the patient's life resource.

The objective of the invention is to ensure the adaptation of the device to perform cryodestruction of the myocardial sections along targeted paths in the treatment of atrial fibrillation from the epicardium, and, as a result, reducing the time of the procedure included in the total time the patient is under general anesthesia.

The problem is solved in that in a cryosurgical applicator containing a cylindrical core of porous titanium nickelide, axially mounted on a wire holder made of titanium nickelide, according to the invention, the core is made with a longitudinal protrusion in the form of a ridge and with it is smoothly bent along the length by an angle of 20 -30 degrees in a plane orthogonal to the radial orientation of the ridge relative to the radius of the circle, of which the curved length of the core is a part. Ease of use is enhanced by the fact that the holder in the region adjacent to the core is bent twice from the axis of the radius of the circle, part of which is the bent length of the core, while the first bend is made at an angle of 100-130 degrees from the reduced axis of the radius of the circle in the direction that continues to bend the core and the second bend is made so that the continuation of the rectilinear distal part of the holder is projected onto the middle of the core.

The connection of distinctive features with the achievement of a technical result is due to the following.

1. The implementation of the core with a longitudinal protrusion in the form of a ridge ensures the presence of a pronounced narrow zone for contact with epicardial tissues in a selected extended area.

2. The smooth bending of the core together with the comb-like protrusion provides the curvature of a narrow extended section of cryodestruction in accordance with the anatomical configuration of the affected area.

3. The direction of the bend in the plane orthogonal to the radial orientation of the ridge, provides the convenience of manipulation in the operating area with the possibility of visual control.

4. The choice of the bending angle of the core with the ridge within 20-30 ° was carried out expertly, taking into account the real characteristics of the curvature of the extended sections of cryotherapy.

5. Bends of the holder provide usability of the cryoapplicator. Bending in the same direction as the core gives the entire structure a flat outline with a minimum volume, increasing the convenience of storage, sterilization, as well as the uniqueness of the lying position, which is important for capture in a limited time.

6. The presence of a double bend of the holder allows you to hold the device in your hand without the risk of scrolling, and the orientation of the distal part in the direction of the middle of the core allows you to organoleptically predict the position of the core with difficult visualization.

7. The choice of the angle of the first bend of the holder within 100-130 ° was carried out expertly, taking into account the implementation of the second bend over the middle of the core. Moreover, the choice of the second bend point is determined intraoperatively, in accordance with the desired inclination of the core relative to the distal part of the holder.

Thus, the claimed distinctive features in their totality ensure cryodestruction of the atrial myocardial tissue from the epicardium adequate to their anatomical structure and the nature of the procedure, allowing it to be performed in the shortest possible time and with high accuracy.

The invention is illustrated in figures 1-3.

Figure 1 schematically shows the design of a cryosurgical applicator:

1 is a cylindrical core;

2 is a wire holder;

3 is the crest of the core;

4 - this is the first bend of 100-130 degrees;

5 - this is the second bend of 100-130 degrees;

AA is a cross section of a porous core.

Figure 2 shows a photograph of the device. Figure 3 photograph of the moment of operation with a cryoapplicator. The cryosurgical epicardial applicator (Fig. 1) comprises a cylindrical core 1 made of porous titanium nickelide, axially mounted on a wire holder 2 made of titanium nickelide. The difference of the claimed cryoapplicator is that the core is made with a longitudinal protrusion in the form of a crest 3 and with it is smoothly curved along the length by an angle of 20-30 degrees in a plane orthogonal to the radial orientation of the crest relative to the radius of the circle, of which the curved length of the core is a part. The holder 2 in the area adjacent to the core is bent twice from the axis of the radius of the circle, part of which is the curved length of the core, while the first bend 4 is made at an angle of 100-130 degrees from the reduced axis of the radius of the circle in the direction that continues to bend the core, and the second bend 5 is configured such that a continuation of the rectilinear distal portion of the holder is projected onto the middle of the core. The illustration shows embodiments of the second bend of the holder, characterized by different inclination of the core. Due to the superelasticity of the holder material, bending is carried out quite arbitrarily and without effort.

The device is used as follows (figure 1). Aseptically pre-treated device is used during the main stage of the operation on a cardiopleated heart. For the holder 2, the cylindrical core 1 is immersed in a refrigerant (liquid nitrogen). The porosity of the material ensures filling within 3-5 s, the criterion for filling is to stop the release of bubbles above the surface of the core. After that, manipulating the holder 2, cryoablation of the target areas of the myocardium (procedure "labyrinth") from the side of the epicardium is performed. Cryotherapy is carried out by the crest of the core 3, the bend 4 of which provides contact with the surface of the heart on purposefully selected fragments of the trajectory of the "maze". At the same time, to clarify the trajectory, you can apply the point impact of the core end. With all manipulations, accidental touches of tissues are avoided due to the possibility of freezing, accompanied by mechanical damage. The duration of cryotherapy is determined by the rate of evaporation of the refrigerant from the pores of the core 1 and is 10-15 s. The freezing zone is monitored visually.

To confirm the operability of the device and the attainability of the technical result with its help, a study of the inventive cryoapplicator was carried out in 2 stages: 1) experimental, 2) clinical.

At the first stage, the possibility of performing myocardial ablation was studied. A series of experiments was conducted on 12 laboratory rats of the Wistar strain, using the inventive applicator, cryotherapy was applied to the apex of the left ventricle for 15 seconds. Groups were identified by the timing of removal from the experiment: after 15 minutes, after 10 days, after 20 days and after 30 days, 3 experimental animals in each group. A morphological study of the exposed myocardium was performed. Myocardial thickness before exposure was 4.4 ± 0.43 mm. After exposure, the thickness of the myocardium in the affected area was 3.9 ± 0.30 mm. The damage zone after 15 minutes averaged 2.8 mm, after 10 days the thickness of the granulation tissue was 3 mm, and after 10 days it was 3.1 mm. After 30 days, the appearance of scar tissue up to 3.5 mm thick, 0.4 mm intact tissue was noted. Thus, it was found that the cryodestruction region penetrates almost the entire thickness of the myocardium.

At the second stage, a series of operations was performed in patients with paroxysmal and persistent atrial fibrillation. The number of patients was 7 people. The restoration of sinus rhythm in the postoperative period was noted.

Clinical example. Patient S., 55 years old, was examined and treated at the cardiac surgery department of the Research Institute of Cardiology SB RAMS from 01.10.2012 to 02.02.12 with a diagnosis of Main diagnosis: coronary artery disease, angina pectoris, stenotic atherosclerosis of the coronary arteries. Paroxysmal form of atrial fibrillation.

In accordance with the patient’s underlying disease, surgical treatment was performed on January 12, 2012: bimammarocoronary bypass surgery: a. mammarla sinistrae sequential shunting of a branch of a blunt margin, a median artery; a. mammaria dextrae bypass of the anterior descending artery. Coronary artery vein bypass grafting of the right coronary artery. Epicardial cryoablation of the proposed device using liquid nitrogen of the mouth of the pulmonary veins and the left atrial abalone in conditions of cardiopulmonary bypass and cardioplegia with Custodiol solution (Fig. 3). Cryotherapy was performed with a core crest, the bend of which provided contact with the surface of the heart on purposefully selected fragments of the “labyrinth” trajectory. With all manipulations, accidental touching of tissues was avoided due to the possibility of freezing, accompanied by mechanical damage. The duration of cryotherapy was 15 s. The freezing zone was monitored visually. Relative ease of manipulation is noted. Immediately at the end of the main stage of the operation and the restoration of cardiac activity, a sinus rhythm was obtained, which persisted both in the early and late postoperative period. The postoperative period was uneventful. Postoperative wound healing by primary intention. The patient was discharged on the 21st day after surgery with a sinus rhythm.

The claimed design of the cryosurgical epicardial applicator, in addition to the treatment of AF, can be recommended for use on other organs with similar anatomical features.

Bibliography

1. Go A.S., Hylek E.M., Phillips K.A. et al. Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study // JAMA. - 2001 .-- Vol.285. - P. 2370-2375.

2. Feinberg W. M., Cornell E. S., Nightingale S. D., et al., For the Stroke Prevention in Atrial Fibrillation Investigators. Relationship between prothrombin activation fragment F1.2 and international normalized ratio in patients with atrial fibrillation. Stroke 1997; 28: 1101-6.

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Claims (2)

1. A cryosurgical epicardial applicator containing a cylindrical core made of porous titanium nickelide, axially mounted on a wire holder made of titanium nickelide, characterized in that the core is provided with a longitudinal protrusion in the form of a comb and with it is smoothly curved in length by an angle of 20-30 degrees in a plane orthogonal to the radial orientation of the ridge, with the ability to provide contact with epicardial tissues over an extended cryotherapy site. 2. The cardiac surgical epicardial applicator according to claim 1, characterized in that the holder is twice bent in the plane of bending of the core with the ability to ensure the curvature of the extended section of the crest destruction in accordance with the anatomical configuration in the area of the procedure, while the first bend is made at an angle of 100-130 degrees the direction continuing the bending of the core, and the second bending is made in the distal part of the holder in the direction of the middle of the core.

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