Study of Biointegration and Elastic-Strength Properties of a New Xenopericardium-Based Biomaterial for Reconstructive Cardiovascular Surgery.

We analyzed biocompatibility, elastic-strength properties, and biointegration potential of a new biomaterial made of xenopericardium for reconstructive cardiovascular surgery. The biomaterial manufactured by the proposed technology demonstrated high biocompatibility and biointegration potential and its elastic-strength properties 2-4-fold surpassed that of native pericardium. The obtained results attested to good prospects of using the proposed technology for preparing biomaterials for reconstructive cardiovascular surgery.

[Post Radiotherapy Lesions of the Heart Valves. Principles of Diagnosis and Results of Treatment].

BACKGROUND: The use of radiation therapy for the treatment of tumors of the chest сan lead to the development of cardiac pathology, including that of the valves and coronary arteries. STUDY AIM: to analyze the specifics of post-radiation lesions of the valvular apparatus and coronary arteries, and to assess the immediate results and risks of surgical correction of detected defects. Materials and  methods. In the Emergency department of surgery of acquired heart disease of A. N. Bakulev National Medical Research Center of Cardiovascular Surgery in the period from 2004 to 2017 were examined and operated 46 patients aged 35-81 years (mean age 56±12.4 years, 80 % women). The period from primary irradiation of the chest to surgical treatment of valvular pathology ranged from 4 to 40 years. Indications for thoracic radiotherapy were Hodgkin's lymphoma in 23 patients (50 %), breast cancer - in 20 (43 %). RESULTS: Stenosis of the aortic valve was the leading defect in 42 patients (91 %). According to coronary angiography, coronary artery disease was diagnosed in 31 patients (67 %). Isolated aortic valve prosthesis was performed in 14 (30 %) patients, other operations were combined. Hospital mortality was 11 % (5 patients). There were no deaths among patients who underwent radiation therapy after mastectomy. Main nonlethal complications were: pericardial effusion in 6 patients (13 %), hydrothorax requiring repeated pleural punctures in 5 patients (11 %). CONCLUSION: The variety of clinical manifestations of radiation heart disease and its progressive nature emphasize the need for long-term dynamic observation of patients after thoracic irradiation in order to timely identify the pathology and eliminate the risk of sudden cardiac complications and the development of severe heart failure decompensation.

[Low-traumatic approach in secondary surgery on the aortic valve].

The possibility of a second operation on the aortic valve and root using a minimally invasive approach is considered along with discussion of its traumaticity and peculiarities of the postoperative period.

[The myosin-activating protein kinases in human myocardium: localization and content].

Using the immunofluorescence approach, we have determined that the recently detected protein kinases, among which are RhoA-activated kinase, integrin-linked kinase, zipper interacting protein kinase, and death-associated protein kinase, which are capable of phosphorylating myosin, are localized in the Z-lines sarcomeres of human myocardium. Additionally, we studied the content of integrin-linked and zipper interacting protein kinases in human embryonic myocardium, as well as in normal and hypertrophic adult human heart. The content of these protein kinases in adult normal myocardium increases in comparison with the embryonic heart. The content of integrin-linked and zipper interacting protein kinases in hypertrophic myocardium is higher compared with the normal adult heart. The data obtained suggest the involvement of these protein kinases in the development and hypertrophy of human heart.

[Autoantibodies to light myosin chains as an early marker of damage to the myocardium].

The concentration of autoantibodies to myosin light chains in the blood serum of patients who have undergone operation on heart under conditions of artificial hypothermal circulation was measured after 3, 6, 9, 18, 24, 36 h following the reperfusion of myocardium. According to the postoperative data, the patients were divided into three groups: patients with stable hemodynamics in the postoperative period (group 1); patients with myocardial stunning following reperfusion of myocardium (group 2); and patients with severe heart failure that developed in early postoperative period (group 3). Significant differences in the concentration of autoantibodies to myosin light chains have been found between the groups. A high correlation was established between the duration of cross-clamping of aorta and the concentration of autoantibodies. By means of multivariant regression analysis, factors characterizing the initial severity of disease that can influence the concentration of autoantibodies to myosin light chains in blood have been revealed.

[Cryopreserved allo-grafts in aortic valve surgery].

Bakulev Scientific Center for Cardiovascular Surgery resumed research into cryopreservation and creation of valve bank in 1990. This technology allowed preparation of valve allo-grafts with preserved cell reproductive capacity for clinical use. A new technology, allowing reduction of calcinosis in the graft's aortic wall, was developed and experimentally tested in 2003. 61 aortic valve replacements with cryopreserved allo-grafts were performed between 1992 and 2003. The three techniques of implantation included: subcoronary (38), intraaortic cylinder (8) and "free-standing root" (15). 44 patients developed active infective or prosthetic endocarditis. Hospital mortality rate was 11.5%, 12-year survival rate--90%. Dysfunctions and reoperations were significantly rarer in cases of inclusion cylinder and free standing root. The authors conclude that cryopreserved allo-grafts allow good quality of life without use of anticoagulants and low rate of reinfection. The use of subcoronary technique for implantation must be limited and method of choice should be free-standing root, especially in cases of destructive infective or prosthetic endocarditis. Cellular engineering probably will elongate the stability of long-term results.

[Clinical appliance of new biologic glue "Biokley-LAB" in cardiac surgery with artificial circulation]. / Klinicheskoe primenenie novogo biologicheskogo kleia "Bioklei-LAB" pri operatsiiakh na serdtse v usloviiakh iskustvennogo krovoobrashcheniia.

Data on clinical appliance of domestically produced two-component gelatin-resorcin glue "Biokley-LAB" in difficult surgeries on the ascending aorta and aortal valve with artificial circulation demonstrate that this glue is good prophylactic haemostatic remedy which reduces risk of postoperative bleedings.

Eight years clinical experience with the replacement of the ascending aorta using composite xenopericardial conduit.

OBJECTIVE: The evaluation of early and late results after ascending aorta replacement with composite glutaraldehyde-treated xenopericardial valved conduit. METHODS: From December 1989 to May 1999 the ascending aorta was replaced with 148 composite xenopericardial conduits aorta in 145 patients. Biological valves were inserted in 28 conduits, mechanical valves - in 116. The age of 40 female (28%) and 105 male (72%) patients ranged from 10 to 60 years (mean, 38.7+/-12 years). The original diseases were: atherosclerosis in 51 (35%), cystic media necrosis in 50 (35%), Marfan syndrome in 35 (24%), syphilis in three (2%), non-specific aortitis in one (0.7%), Turner syndrome in one and infective endocarditis in four cases. Aortic dissection was found in 67 patients (46%): type I in 14 (23%) and type II in 53 (77%). Twenty-one patients (15%) were operated on during the acute phase of the dissection. The Bentall-DeBono technique was used in 144 operations, in four cases (2.7%) supracoronary resection was performed. Associated procedures included: mitral valve repair (five), CABG (four), resection of the coarctation (two), MV replacement (two). Biological tissues condition was assessed using TTE TEE and computed tomography (CT) scanning technique. RESULTS: Hospital mortality was 8.3 % (12 patients). The death was caused by: low cardiac output (three), arrhythmia (two), neurological complications (one), sepsis (one), polyorgan failure (four), bleeding (one). Non-lethal complications included: bleeding (four), heart failure (two), persisting A-V block (two), polyorgan failure (three), cerebral (two), mediastinitis (three), and early prosthetic endocarditis in three patients. All three patients with endocarditis were successfully re-operated and conduit replaced with the same type of the device. Late follow-up ranged from 2 months to 8 years (mean, 51 months) and complete in 87% of the discharged patients (115 patients). There were four valve-related deaths due to thrombembolia and five deaths non related to the valve and/or conduit. Clinical and instrumental evaluation did not reveal any signs of tissue degeneration at the conduit and biovalves' cusps. CONCLUSIONS: The xenopericardial valved conduit is an effective and acceptable device for the replacement of ascending aorta in almost all cases, it provides good early and late results. It's pliability and elasticity are especially attractive in situations with frail tissues and high risk of bleeding.

[Migration of fibroblasts into heart valve leaflet tissue in vitro]. / Izuchenie migratsii fibroblastov v tkan' stvorok klapanov serdtsa in vitro.

Heart valve allografts are widely used for surgical treatment of the heart. In recent years a new field of research has emerged dealing with allograft modification by cells of recipient by means of tissue engineering. This method involves culturing fibroblasts and endothelial cells, using recipient tissue, followed by introduction of the fibroblasts into tissues of allograft and coating its surface by the endothelial cells. This modification is expected to ensure the structural maintenance of implanted tissues and to reduce its thrombogenecity. This procedure may promote the allograft adhering to the recipient tissues, thus prolonging the terms of the valve normal functioning after implantations. For this purpose, methods of luminescent microscopy are suggested using double staining of tissue with fluorescent dyes Hoechst 33,342 and ethidium bromide, or with fluorescein diacetate and ethidium bromide. Experimental results are presented indicative of fibroblast migration from the surface to the human heart valve leaflets.

Autoantibodies to myosin light chains in the blood as early marker of myocardial injury after aortocoronary bypass surgery.

Serum concentration of autoantibodies to myosin light chains was measured after resumption of the bloodflow recovery in patients who underwent hypothermic aortocoronary bypass surgery. The patients were divided into 3 groups according to postoperative hemodynamic parameters and degree of myocardial injury. The studies showed significant differences in the concentrations of autoantibodies to myosin light chains between the groups. High correlation was shown between the duration of aorta clamping and concentration of autoantibodies to myosin light chains. Some factors characterizing initial severity of the disease can modulate blood concentration of autoantibodies to myosin light chains.

Improving biocompatibility of heart valve and vascular transplants by their devitalization and repopulation by recipient cells.

Inoculation of cells derived from the aorta of Wistar rats on devitalized porcine aortic walls 2-4-fold reduced their calcinosis after subcutaneous implantation to Wistar rats. Inoculation of Wistar rat bone marrow mesenchymal cells selected by adhesion activity did not reduce tissue calcinosis. The results indicate good prospects of repopulation of devitalized heart valve and vessel transplants by recipient vascular cells for reducing transplant calcinosis and improvement of their biocompatibility.

[The effect of normothermic cardioplegic reperfusion with phosphocreatine on the recovery of the cardiac functional indices after total ischemia]. / Vliianie normotermicheskoi kardioplegicheskoi reperfuzii s fosfokreatinom na vosstanovlenie funktsional'nykh pokazatelei serdtsa posle total'noi ishemii.

Experiments were conducted on a model of an isolated functioning rat heart to study myocardial protection by normothermic cardioplegic reperfusion (NCR) with phosphocreatine (PC) in 30-minute total ischemia at 37 degrees C. Five series of experiments were performed: (1) cardioplegia (K+ 30 mM/l, Mg2+ 15 nM/l, osmolarity 330 MOSM/l), ischemia, NCR not applied; (2) the same solution was introduced in the preischemic period, ischemia, NCR (K+ 15 mM/l, Mg2+ 15 mM/l, osmolarity 360 MOSM/l); (3) with the same experimental schedule, PC (10 mmol/l) was added to the cardioplegic solution in the preischemic period; (4) in a similar experiment PC was added in the stage of NCR; (5) PC administered in the preischemic stage and in NCR. Restoration of heart functional parameters, rate and ejection of lactate dehydrogenase into the perfusate were compared. The results of the experiment bear evidence that NCR protects the myocardium from reperfusion damage in normothermic ischemia. The optimal cardioprotective effect of PC is produced when it is administered in the preischemic stage. PC added to the solution for NCR has no positive effect on the restoration of heart functional parameters.

[Additional myocardial protection by normothermic cardioplegic reperfusion]. / Dopolnitel'naia zashchita miokarda s pomoshch'iu normotermicheskoi kardioplegicheskoi reperfuzii.

Three series of experiments were conducted on a model of an isolated working rat heart to study the efficacy of variants of cardioplegic myocardial protection in exposure to 30-minute total ischemia at 37 degrees C: (1) preischemic administration of potassium solution (K(+)-30 mM, Mg(2+)-1.6 mM, osmolarity 330 MOSM/1); ischemia, unmodified reperfusion; (2) preischemic administration of this solution, ischemia, postischemic administration of this solution for 5 minutes (normothermic cardioplegic reperfusion), putting in a working regimen; (3) the regimen of the experiments is the same as in series 2, but normothermic cardioplegic reperfusion was carried out with a modified potassium-magnesium solution (K(+)-15 mM, Mg(2+)-15 mM, osmolarity 360 MOSM/1). The values of functional restoration, rate and total discharge of the enzyme LDH into the perfusate were compared. Restoration of functional values (aortic pressure, aortic output, cardiac index) according to the experimental series: 3 greater than 2 greater than 1. LDH discharge into the perfusate: 3 less than 2 less than 1. The results of the study provide evidence that reperfusion damage may be lessened by normothermic cardioplegic reperfusion; the highest effect was produced by a solution with specially selected properties: electrolyte composition and high osmolarity.

[Rupture of posterior wall of the left ventricle after mitral valve prosthesis]. / Razryv zadnei stenki levogo zheludochka posle protezirovaniia mitralnogo klapana.

Rupture of the posterior wall of the left ventricle is a comparatively rare complication occurring after prosthesis of the mitral valve, but resulting in high mortality. There is a great diverse of opinions regarding the causes of this complication. The likely causes are surgical injury and the used method for prosthesis. The authors studied 9 patients with rupture of the posterior wall of the left ventricle following mitral prosthesis. In all patients the prosthesis was carried out by the routine procedure by dissecting the two mitral cusps with subvalvular structures. Two (22%) patients survived after defect plasty. The above surgical policy is the most effective to control bleeding and achieve a favourable result of correction of this complication.

[Comparative assessment of variants of potassium crystalloid cardioplegia]. / Sravnitel'naia otsenka variantov kalievoi kristalloidnoi kardioplegii.

Sixty eight patients operated on for valvular abnormalities were examined. In Group 1 (n = 34) myocardial protection was made by potassium solutions containing different potassium concentrations: 30 mM and 5 mM for induction and reinfusion, respectively. In Group 2 (n = 34) a hyperosmolar oxygenized cardioplegic solution containing K+, 15 mM, and Mg2+, 16 mM was administered under the same conditions. In the early postoperative period, no differences were found in the frequency and size of inotropic support, as evidenced by central hemodynamic parameters. ECG showed that in Group 2 there was a reduction in the frequency of changes of S-T segment, indicating the presence of myocardial ischemic changes. A 24-hour Holter monitoring demonstrated that life-threatening ventricular arrhythmias occurred significantly more infrequently in Group 2. The ultrastructural study of intraoperative biopsy specimens of the myocardium, including their treatment with colloid lanthanum showed that the tracer had penetrated virtually into all cardiomyocytes at the peak of ischemia and reperfusion in Group 1. In Group 2, ultrastructural changes were less profound and the particles of the tracer lanthanum had penetrated into the sarcoplasm of 15% of cells. Inadequate myocardial protection cannot be regarded as a cause of one of three deaths from acute heart failure. The studies demonstrated that crystalloid potassium cardioplegia was highly effective. However, the possibility of additionally affecting the permeability of a cell membrane by changing the solution composition (elevating magnesium concentrations) and the reduction of frequency of cardiac arrhythmias suggest that each components of the cardioplegic solution should be studied.

[Prosthesis of the aortic valve by a loose allograft]. / Protezirovanie aortal'nogo klapana beskarkasnym allograftom.

A procedure has been developed to prepare live aortic allografts, which consists in taking a valve early after a donor's death, sterilizing it in antibiotics and freezing it to -190 degrees C in the presence of the cryoprotective agent dimethylsulfoxide. The preservation of valve tissue is evidenced by morphological studies. The first 3 operations for aortic valvular diseases were performed. In two cases, the indication for surgery was infectious endocarditis refractory to antibiotic therapy. Postimplantation complications were not seen. The competence of the allograft was confirmed by intraoperative transesophageal echocardiographical study. The patients examined 4 months postoperation developed no signs of aortic incompetence and infectious endocarditis. Thus, the creation of a bank of live valves allows this prosthesis to be implanted with appropriate indications, one of which is active infectious endocarditis of the aortic valve.