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Biomedical subjects

V S Chekanov

Publications and source records attributed to V S Chekanov.

At least 19 recordsLinked to original sources
PubMed2000

Biodesign of a skeletal muscle flap as a model for cardiac assistance.

In using autologous muscles for cardiac assistance, it is crucial to reduce ischemia-reperfusion injury in the surgically traumatized skeletal muscle. In adult sheep, we developed a simple model of surgically designed 2 latissimus dorsi muscle leaflets by modifying the vascular supply to these leaflets. Three pockets with graded injury were established, and muscle morphology and vascular remodeling were monitored in 3 experimental groups: muscle leaflets without any treatment (Group 1, n = 6) that served as controls; muscle leaflets integrated with a fibrin interlayer (Group 2, n = 6); and leaflets integrated with fibrin and entrapped pyrrolostatin (Group 3, n = 6). We applied the fibrinogen and thrombin solutions, which polymerize to form a three-dimensional meshwork joining the tissues, creating a provisional matrix for angiogenesis, and acting as a delivery depot for agents aimed at minimizing ischemia-reperfusion lesion formation. After 2 months, the muscle leaflets biointegrated with the fibrin interface showed none of the signs of necrosis or ischemia-reperfusion lesions seen in the controls. Although no angiogenic factors were incorporated, the fibrin interlayer rapidly (<2 weeks) became a densely vascularized tissue replete with a voluminous capillary network. In contrast, controls showed poor bonding between the tissues, muscle fiber deterioration, and a compromised vascular network. Muscle structure was best preserved and angiogenesis was greatest when pyrrolostatin, a free radical scavenger, was added to the fibrin meshwork to reduce damage caused by overproduction of free radicals. This newly designed model will be useful to study many current approaches in cardiovascular biology, from pharmaceuticals to gene therapy, which might prove advantageous in muscle-designed cardiac assistance.

Animals↗
PubMed2000

Effects of electrical stimulation postcardiomyoplasty in a model of chronic heart failure: hemodynamic results after daily 12-hour cessation versus a nonstop regimen.

The hemodynamic effects of cardiomyoplasty (CMP) have been investigated in many centers, but the question of whether it is necessary to stimulate the latissimus dorsi muscle (LDM) 24 hours a day has not been answered. The main goal of our investigation was to determine whether hemodynamic results after CMP were impaired when continuous electrical stimulation (ES) was off for 12 hours a day. A model of chronic heart failure was created in 12 sheep by performing an arteriovenous anastamosis and administering doxorubicin. Two weeks after the anastomosis, CMP was performed in eight sheep (experimental series); ES training was begun at 2 weeks after CMP. After completion of the initial ES conditioning (8 weeks after CMP), one group of sheep continued to receive ES 24 hours daily. Another group of sheep had only 12 hours of ES daily. Hemodynamic parameters were investigated 2 weeks later with the stimulator turned on and then off. With doxorubicin administration, arteriovenous anastamosis created a stable model of biventricular heart failure (right atrial pressure 20 +/- 3 mmHg vs 6 +/- 2 mmHg at baseline; pulmonary capillary wedge pressure 18 +/- 3 mmHg vs 9 +/- 2 mmHg; left ventricular end-diastolic area 15.2 +/- 1.2 cm2 vs 6.4 +/- 0.7 cm2; left ventricular ejection fraction 0.38 +/- 0.6 vs 0.65 +/- 0.7). Cardiomyoplasty improved hemodynamic status in all eight experimental sheep. However, when the investigation was performed with the stimulator off, this improvement was statistically insignificant. With stimulation on, there was decreased right atrial pressure, pulmonary capillary wedge pressure, left ventricular end-diastolic volume, and increased left ventricular ejection fraction. With the stimulator turned off for 12 hours daily, hemodynamic measurements did not differ from data with continuous ES for 24 hours daily. Because hemodynamic results do not seem to be impaired, we recommend daily, periodic cessation of stimulation to prevent damage to the LDM after CMP.

Animals↗
PubMed1998

Cardiomyoplasty after implantation of a pacemaker and cardioverter/defibrillator.

Presently, a combination of two surgical methods improves the survival of patients with advanced ventricular dysfunction: implantable cardioverter/defibrillator implantation (which prevents sudden cardiac death) and cardiomyoplasty (which prevents further dilatation of the heart and provides additional cardiac assistance). We report the clinical course of a patient who had cardiomyoplasty after cardioverter/defibrillator implantation and pacemaker insertion. It is a rare case in which three different devices cardioverter/defibrillator, pacemaker, and cardiomyostimulator) are functioning together without crosstalk.

Adult↗
PubMed1991

[Adaptive transformation of the architectonics of the left ventricle at long periods following implantation of an apico-aortic conduit (based on data from an experimental study)].

An original morphological study has been conducted to identify the mechanisms underlying the morphofunctional transformations of the left-ventricular structures taking place at late terms after implantation of the apico-aortal conduit. Analysis of the moulds of the left-ventricular cavity has convincingly demonstrated the peculiar changes in its structures bringing about alterations in the blood ejection mechanism on creation of a new outflow tract from the left ventricle of the heart. The conclusions derived from this work are essential not only for implantation of the apico-aortal conduit but for understanding the mechanisms of blood ejection in some congenital heart diseases.

Adaptation, Physiological↗
PubMed1991

[Evaluation of the status of cardiac perfusion after implantation of extra-cardiac conduits].

The work discusses the findings of experimental study of perfusion of the myocardium after creation of a peculiar "new" outflow tract from the left ventricle of the heart. As a result, perfusion of a heart with an unnatural outflow tract from the left ventricle was found to be satisfactory. The authenticity of the results was determined by means of two, complementing each other, radioisotope methods--standard study with the use of 201Tl and a new method for producing a positron-emission image. It is concluded that the supply of blood to the myocardium after implantation of an ++apico-aortic conduit is sufficiently effective.

Animals↗
PubMed1991

[Morphogenesis of apico-aortic conduit implantation (data of an experimental study].

The article discusses the results of complex morphological research concerned with study of the histological structure of an extracardiac conduit in late-term periods after its implantation into the left ventricular-aortic position. The authors conducted a qualitative analysis of the morphogenesis of implantation of a conduit--an original new outlet tract from the left ventricle of the heart. The rich experimental material confirms the conclusion that the new outlet tract from the left ventricle of the heart is marked by complete functional competence adequate for conditions of systemic circulation.

Animals↗
PubMed1991

[Dynamic atriomyoplasty as a method extending F. Fontan's principle in the surgical treatment of complex congenital heart defects (an experimental study)].

The article discusses the data of an original complex experimental research dealing with the study of the possibilities of the method of dynamic cardiomyoplasty in surgical management of complex congenital heart diseases with critical obstructive lesions of the venous atrioventricular valve. An original method for the formation of a peculiar new pumping chamber into the system of pulmonary circulation is described. The hemodynamic efficacy of the operation in the immediate periods after its performance is thoroughly evaluated. Substantiated recommendations are given for the possible use of this method in the clinic in surgical treatment of this difficult contingent of patients.

Animals↗
PubMed1990

[Percutaneous transcatheter assisted circulation].

A new system of percutaneous transcatheter auxiliary circulation of blood was developed and approved in the period between 1988 and 1989. The system includes a portable centrifugal pump and special catheters with a thin wall and diameter measuring 2-4 mm. Experiments (25) on a vascular channel model showed that the system provides for a 3.5 l/min performance and does not cause damage to the formed elements of the blood in operating for 240 minutes. This type of auxiliary circulation was used in 16 experiments on mongrel dogs with acute disturbance of coronary circulation (occlusion of the anterior interventricular branch of the left coronary artery (AIVB) with a balloon catheter for 60 minutes). The viability of the myocardium in the zone of the occluded AIVB was maintained and its function completely restored in the postischemic period in all cases. In the control group (5 experiments) the zone of the infarction accounted for 40 to 60% of the mass of the myocardium supplied by the AIVB. The use of the method is very promising in acute disorders of coronary circulation.

Animals↗
PubMed1990

[Cardiomyoplasty].

The article analyses the current state of the problem of cardiomyoplasty as a new method for the treatment of patients with myocardial cardiac insufficiency. The authors show the experimental and clinical material on the possibility and efficacy of using skeletal muscles for improving myocardial contractility and raising the cardiac index. Experience gained in our country (6 operations) in cardiomyoplasty in patients with severe form of ischemic heart disease is discussed. The authors used an original Soviet produced cardiosynchronized electroneurostimulator "Stiminak" for stimulation of the muscles. Analysis of personal experimental material allows new ways for the development of the problem to be planned.

Animals↗