RU2362492C1 - Method of aortic and pulmonary artery homograft isolation from donor heart - Google Patents

Abstract

FIELD: medicine; cardiosurgery.

SUBSTANCE: fragments aorta and pulmonary artery together with a valve unit are isolated from donor heart in sterile conditions. Then isolated homografts are estimated for adaptability. The fragments of aorta and pulmonary artery together with the valve unit are isolated in a sequence as follows: aorta and pulmonary artery are divided to fibrous rings of aortic and pulmonary valves; it is followed with excision of distal parts of pulmonary artery 2 cm away from artery mouths; left and right coronary arteries are isolated from epicardium and cut off 0.7-1 cm away from mouths; right ventricle of heart and interventricular septum are cut off 2-2.5 cm away from pulmonary valve in parallel to coronary transverse from heart edge to interventricular septum; then pulmonary homograft with muscular flange 2-2.5 cm of right ventricle of heart is isolated from fibrous ring, while aortic homograft with a flange 1.5-2 cm is isolated from fibrous ring of valve, herewith mitral valve anterior leaflet is left without chords to be cut off with shortening muscular flanges of transplants up to 0.5 cm in width and thickness. To test the valve unit for adequacy, homografts are turned inside out to make a visual inspection of valves, sinuses and vascular walls.

EFFECT: method allows standardising tissue preparation for transplantation, reducing number of damages of valve unit, isolated homografts, decreasing defect ratio and reduction cost price of commercial homografts, improving functional reliability of a transplant due to removal of models with border changes of valve tissues observed.

Description

The invention relates to cardiac surgery, in particular to methods for isolating vascular homografts from a donor heart and preparing them for subsequent transplantation into the aortic position for aortic valve defects and diseases of the ascending aorta.

Valvular defects account for about 25% of all heart diseases. In terms of their prevalence, they are second only to IHD and hypertension [4]. Pathology of the aortic valve occurs in 30-35% of patients with heart defects [3]. In 2005, in Russia the number of patients with acquired heart defects was 211.5 per 100,000 population [1]. The estimated need for cardiac surgery for this pathology in Russia is 320 operations per 1 million people [1, 2]. Mechanical artificial valve prostheses do not fully meet the requirements. The creation of prosthetic heart valves that have similar to natural hemodynamic characteristics, resistant to infection, do not require anticoagulant therapy, is an urgent task of modern medicine. In the mid-1980s, the use of xenografts (valves obtained from specially grown animals), as well as cryopreserved and native homografts (human donor valves) began [5, 8, 9, 10]. Homografts have ideal hemodynamic characteristics and are closer to humans in their antigenic composition, which ensures longer functioning when they replace the native valve [13].

Currently, homografts are used in economically developed countries because of the lower risk of thromboembolic complications and infectious endocarditis, as well as better hemodynamic results in the postoperative period [13]. However, the use of homografts is limited by their availability, complexity of processing and storage technology. All this leads to the high cost of the product ready for implantation. In Russia, the use of homografts is limited due to the lack of industrial production of domestic products, the high cost of foreign analogues, which accounts for the small experience of their implantation. In 2006, 6478 prosthetic heart valve prostheses were implanted in our country. Biological prostheses made up only 6%, and implanted homografts - 0.5%. In the Northwest region, in 2004, 761 valve prosthetics were performed and in no case did they use a homograft [1]. In accordance with the program of financing expensive treatment methods of Roszdrav in 2007-2008, a sharp increase in the number of cardiosurgical interventions is planned, which will lead to a shortage of artificial prosthetic heart valves, as well as a significant increase in the need for biological prostheses and homografts.

Homografts in the form of valve-containing conduits are prepared from hearts obtained from cadaveric donors during postmortem autopsy [6]. A homograft is taken from organ donors for organ transplantation, as well as from those killed as a result of car accidents or suicide under the age of 40 years. Donors with infectious diseases, including tuberculosis, syphilis, hepatitis, sepsis, with heart and aortic diseases, cancer patients, patients with collagenoses, dementia, degenerative neurological diseases, as well as patients with an unknown cause of death, are not suitable for isolating a homograft [6, eleven]. After tissue collection, microbiological and serological control is performed [6].

Industrial production of aortic homograft consists of several stages: harvesting, primary processing, preservation, preservation, de-preservation, preparation for implantation.

The most important stage of homograft production is its isolation method, which allows preserving the anatomical relationships of all valve elements and aortic walls, which ensures the efficiency of the valve apparatus after implantation. The most promising for the preservation of all valve elements is a homograft fence with a wide zone of the left ventricular myocardium. However, an excess of muscle tissue subsequently leads to a pronounced immunological reaction and degenerative calcification, which negatively affects the duration of the graft [7]. The proportion of rejected homografts during the period from 1989 to 2001 ranged from 90 to 42% [6]. This is due to the lack of clear quantitative and qualitative criteria for the selection of homografts and the low efficiency of the methods used to assess suitability [6].

The aim of the invention is to increase the proportion suitable for transplantation of homografts of the pulmonary artery and aorta isolated from the donor heart.

To implement a method for isolating homograft of the aorta and pulmonary artery, the heart is removed from the donor under sterile conditions together with a large part of the aorta before the departure of the left subclavian artery, with both pulmonary arteries cut off at the level of the gate of the lungs. It is immersed in a preservative solution and at a temperature of + 5 ° C for 60 minutes is delivered in a sterile container to the laboratory. Isolation of the homograft is carried out under sterile conditions. The apex of the heart is cut off perpendicular to its long axis. The heart is washed with sterile saline to remove blood from the cavities. The selection of the homograft is performed in the following order:

1. Separation of the aorta and pulmonary artery is performed with cutting off the fatty intervascular tissue and epicardium from the distal sections to the fibrous rings of the aortic and pulmonary valves. At this stage, special attention is paid to preserving the wall of the posterior aortic sinus, since it is likely to be damaged. The distal branches of the branches of the pulmonary artery are cut off. There remains a trunk, right and left pulmonary arteries 2 cm long.

2. From the epicardium, the left and right coronary arteries stand out, which are then cut off at a distance of 0.7-1 cm from the mouths.

3. From the lower edge of the right ear of the heart parallel to the coronary sulcus from the acute edge of the heart to the interventricular septum, an incision is made that cuts off the right ventricle and interventricular septum at a distance of 2-2.5 cm from the pulmonary artery valve. Is the selection of pulmonary homograft. The muscular rim from the right ventricle and interventricular septum has a length of 2-2.5 cm from the fibrous ring of the pulmonary valve. A pulmonary artery transplant is placed in a preservative solution.

4. The aortic homograft is cut from the left ventricle at a distance of 1.5-2 cm from the fibrous ring of the valve. Moreover, the anterior mitral valve leaflet without chords remains in the graft. The latter are cut off, and the homograft is immersed in a preservative solution. The aortic graft should continue to the brachiocephalic trunk.

5. Final skeletonization is performed - cutting off adipose tissue from adventitia of homografts. Then the muscle sides of the grafts are shortened to 0.5 cm. Excess muscle tissue is cut off from the outside of the homografts. The thickness of the sides should not exceed 0.5 cm.

6. The validity of the valve apparatus of the grafts is checked. To do this, the homographs turn out. A visual inspection of the dampers, sinuses and vessel walls is performed. If pathological changes are found in the form of fenestra, vegetation, ulcerative defects, perforations, aneurysms, atheromatous plaques, calcification, as well as fresh damage during extraction, homografts are considered unsuitable for use. A water test is carried out for valve tightness.

7. Using the templates of the company "MEDING" to determine the size of the artificial prosthesis of the heart valve, the diameter of the homograft valve is measured. The ruler measures the length of the vessel and its distal diameter. The obtained data are recorded in the homograft passport. After this, the grafts are placed in a preservative solution.

The isolation method was tested in the cardiac surgery department of the Federal State Institution Federal Center for Cardiology and Surgery. V.A. Almazova Rosmedtehnologii ". To develop the technique of isolating an aortic valve-containing homograft, experimental isolation of aortic and pulmonary homografts was performed in 14 cadaveric donors. According to the results of evaluating the viability of the valvular apparatus, 3 aortic homografts were rejected and rejected, which is 21%. In contrast to the prototype [6], clear anatomical landmarks and quantitative criteria were used to isolate the homograft, which made it possible to standardize the process of preparing tissue for transplantation. This technique allows you to reduce the amount of damage to the valve apparatus, emitted homografts, reduces the percentage of "rejection" and in industrial production reduces their cost. The original technique of homograft eversion makes it possible to assess the state of the valve apparatus of the aortic and pulmonary homografts, which allows to increase the reliability of the graft function by removing samples from the production with borderline changes in the tissue of the valve flaps.

Bibliography

1. Bokeria L.A., Gudkova R.G. Cardiovascular surgery. Diseases and congenital malformations of the circulatory system. - M.: Publishing House of the NCCSSH im. A.N. Bakuleva RAMS, 2005 .-- 123 p.

2. Karaskov A.M. Problems of cardiac surgery in Siberia and the Far East. // Pathology of blood circulation and cardiac surgery. - 2001. - No. 1. - S. 5-9.

3. Makolkin V.I. Acquired heart defects. // Diseases of the heart and blood vessels. Ed. E.I. Chazova, T.2 - M .: Medicine, 1992. - S.317-360.

4. Zuckerman G.I., Skopin I.I. Acquired heart defects. // Cardiovascular Surgery, ed. V.I. Burakovsky, L.A. Bokeria. - M., 1989 .-- S. 383-465.

5. Bodnar E, Ross DN. Valvular homografts. // Replacement of Cardiac Valves, New York: McGraw-Hill, Inc. Health Professions Division, 1992. - P.287-306.

6. Jashari R., Van Hoeck B., Tabaku M., Vanderkelen A. Banking of the human heart valves and the arteries at the European homograft bank (EHB) - Overview of a 14-year activity in this International Association in Brussels / / Cell and Tissue Banking 5: 239-251, 2004.

7. Hoekstra F.M.E., Knoop C.J., Vaessen L.M.B. et al. Donor-specific immune response against human cardiac valve allograft // J. Thorac. Cardiovasc. Surg. - 1996. - Vol. 112. - P.281-286.

8. Koolbergen D.R., Hazekamp M.G., de Heer E. et al. The pathology of fresh and cryopreserved homograft heart valves: An analysis of forty explanted homograft valves // J. Thorac Cardiovasc Surg. - 2002. - Vol. 124. - P.689-697.

9. Leyh R. G., Wilhelmi M., Rebe Ph. et al. In vivo repopulation of xenogeneic and allogeneic acellular valve matrix conduits in the pulmonary circulation // Ann. Thorac. Surg. - 2003. - Vol. 75. - P.1457-1463.

10. Takkenberg J.J.M., van Herwerden L.A., Eijkemans M.J.C. et al. Evolution of allograft aortic valve replacement over 13 years: results of 275 procedures // Eur J Cardiothorac Surg. - 2002 .-- Vol.21. - P.683-691.

11. Verghese S., Padmaja P., Sindhu B. et al. Homograft valve bank: our experience in valve banking // Indian Heart J. - 2004. - Vol. 56. - P.299-306.

12. Yankah AC. Forty years of homograft surgery // Asian Cardiovasc Thorac Ann. - 2002 .-- Vol.10. - P.97-100.

13. Yankah A.C., Klose H., Petzina R. et al. Surgical management of acute aortic root endocarditis with viable homograft: 13-year experience // Eur. J. Cardiothorac. Surg. - 2002 .-- Vol.21. - P.260-7.

Claims (1)

A method for isolating homografts of the aorta and pulmonary artery from a donor heart by isolating under sterile conditions sections of the aorta and pulmonary artery together with the valve apparatus and evaluating the suitability of homografts, characterized in that the allocation of sections of the aorta and pulmonary artery together with the valve apparatus is carried out in the following sequence: separate the aorta and the pulmonary artery to the fibrous rings of the aortic and pulmonary valves, the distal sections of the branches of the pulmonary artery are cut off at a distance of 2 cm from the mouths, the left and right coronary arteries are removed from the epicardium and cut off at a distance of 0.7-1 cm from the mouths, the right ventricle and interventricular septum are cut off at a distance of 2-2.5 cm from the pulmonary artery valve, cut parallel to the coronary sulcus from the acute edge of the heart to the interventricular septum , then a pulmonary homograft with a muscular rim of the right ventricle 2-2.5 cm from the fibrous ring and an aortic homograph with a rim of 1.5-2 cm from the fibrous ring of the valve are left, leaving the anterior mitral valve without chords, which cut off irradiate muscle graft edges up to 0.5 cm wide and thick; to check the viability of the valve apparatus, the homografts are turned out, visual inspection of the dampers, sinuses and vessel walls is carried out.