ABSTRACT
We studied a biomaterial for a new domestic product, a biological envelope for implantation of cardiac electronic devices. The product is designed to prevent complications after pacemaker implantation and to facilitate the reimplantation procedure. By chemical and biological processing of raw materials (submucosa of porcine small intestine), an acellular extracellular collagen matrix was obtained. The biocompatibility of the material was tested in vitro using stem cell cultures. The biomaterial for fabrication of the envelope is not cytotoxic, biocompatible, and represents a suitable substrate for attachment, growth, and reproduction of stem cells. The biological effect of the material was studied in vivo on the model of heterotopic implantation in small laboratory animals. The biomaterial did not induce inflammation and tissue reaction and was completely transformed into healthy vascularized tissue without scars in 90 days after implantation.
Subject(s)
Biocompatible Materials/chemistry , Tissue Engineering/methods , Animals , Collagen/metabolism , Extracellular Matrix/metabolism , Inflammation/metabolism , Male , Materials Testing , Myocardium/cytology , Prostheses and Implants , SwineABSTRACT
The observation included 40 patients (20 men and 20 women) with the rheumatic heart diseases acquired at the age of (45.9 +/- 8.7) years after isolated prostheses of the aortal (n = 25) and mitral (n = 15) valves with bicuspid constructions of AHV "MedInzh-2" in remote terms in (2.52 +/- 0.48) years, I-II functional valve (NYHA). It was shown that only a permanent control not rarer than once a month and an adequate correction by means of anticoagulation and antiaggregation therapy using standard methods for patients with the bicuspid AHV made it possible to avoid the development of thromboses and thromboembolic complications during three years of observation.
Subject(s)
Mitral Valve Stenosis/therapy , Pacemaker, Artificial , Thromboembolism/therapy , Thrombosis/therapy , Female , Follow-Up Studies , Humans , Male , Middle Aged , Mitral Valve Stenosis/prevention & control , Thromboembolism/prevention & control , Thrombosis/prevention & controlABSTRACT
Experimental, pathomorphological and clinical data substantiating use of transmyocardial laser revascularisation in the treatment of coronary heart disease (CHD) are presented. It is shown that the objective criterion of clinical efficacy of transmyocardial laser revascularisation in 58 patients with CHD is an increase of myocardial perfusion due to neoangiogenesis. This leads to improvement of cardiac function and general state of the patients. Surgical intervention has no substantial influence on contractile function of left ventricular myocardium in patients with CHD.
Subject(s)
Coronary Disease/surgery , Coronary Vessels/pathology , Laser Therapy , Myocardial Revascularization/methods , Myocardium/pathology , Adult , Animals , Coronary Disease/pathology , Coronary Disease/physiopathology , Dogs , Electrocardiography , Humans , Middle Aged , Myocardial Contraction , Treatment Outcome , Ventricular Function, LeftABSTRACT
Transmyocardial laser revascularization was applied in 58 patients with ischemic heart disease. The objective criterion of the method efficiency was an increase in myocardium perfusion due to newly formed blood vessels under influence of laser irradiation. The laser treatment has improved cardiac function and general condition of the patients. The surgery did not exert considerable influence on the contractile capacity of the myocardium in the patients treated.
Subject(s)
Laser Therapy , Myocardial Ischemia/surgery , Myocardial Revascularization , Adult , Humans , Male , Middle Aged , Myocardial Ischemia/pathologyABSTRACT
According to the International Standard ISO 5840: 1990 the wear resistance test is a necessary step in the development and production of artificial heart valves (AHV). In developing the device, it is important that a reliable prediction is made of AHV longevity, as a number of specific problems appear that are connected with the results of tests, duration of testing, efficiency and reliability of the testing device. In this paper a procedure is outlined of service life testing of mechanical AHV and a description of the device is given. A comparative example of loads acting on AHV, operating in the accelerated wear testing device and in the pulse duplicator of the physiological mode is also described.
Subject(s)
Heart Valve Prosthesis , Materials Testing/instrumentation , Equipment Design , Stress, MechanicalABSTRACT
The main cause of cardiac valve bioprosthesis dysfunction is mechanical rupture of the cusps consequent upon the development of "fatigue" tensions and calcification of the biologic tissue. The technology of "Bionix" prostheses manufacturing implies prevention of these complications by means of supporting frameworks of variable rigidity (dumping stroke loads) and the use of a calcinosis inhibitor in the process of chemical stabilization. Experimental research confirms the certain effectiveness of such an approach to solving the problem of bioprosthesis durability. Experience in clinical application of biological valves of this series showed that by the 5th postoperative year the stability of good results was 90.0 +/- 2.2%; absence of thromboembolic complications in 93.3 +/- 2.4%, and no need to operate because of dysfunction of the bioprosthesis in 96.6 +/- 2.1%.
Subject(s)
Bioprosthesis , Calcinosis/surgery , Heart Valve Prosthesis , Mitral Valve Stenosis/surgery , Adult , Aged , Animals , Calcinosis/complications , Calcinosis/physiopathology , Equipment Design , Female , Humans , Male , Middle Aged , Mitral Valve/physiopathology , Mitral Valve/surgery , Mitral Valve Stenosis/etiology , Mitral Valve Stenosis/physiopathology , Postoperative Period , Swine , Time Factors , USSRABSTRACT
It has been shown that Bionics prostheses compare very favorably with bioprostheses based on rigid supporting frameworks. The advantages of the above prostheses lie in the fact that the supporting frameworks of changed stiffness used in their modelling possess damping capacities at minute physical loadings, which considerably improves the hydrodynamic characteristics of biovalves.
Subject(s)
Bioprosthesis , Heart Valve Prosthesis , Mitral Valve/surgery , Animals , Bioprosthesis/standards , Heart Valve Prosthesis/standards , Humans , Models, Cardiovascular , Prosthesis Design , SwineABSTRACT
LIKS-2 rotatable disk prostheses were tested in laboratories for wear, atraumatic performance, and hemodynamic efficacy. Accelerated tests on testing units demonstrated their high reliability and lasting performance. The values of drops in, pressure and regurgitation volumes were negligible. The late-term results (of up to 5 years) of using LIKS-2 prostheses for correcting mitral and aortic valvular diseases were studied in the department of heart surgery of the All-Union Scientific Centre of Surgery. The prostheses showed high thrombo-resistance, mechanical reliability, and atraumatic performance in patients in the late-term follow-up periods.
Subject(s)
Heart Valve Prosthesis , Aortic Valve/surgery , Evaluation Studies as Topic , Humans , Mitral Valve/surgeryABSTRACT
Studies of the hemodynamic features of the blood flow in extracardiac conduits allow for a grounded and aimed approach to the prosthesis design. The lack of interrelationship between the duct geometry, the flow pattern, and the heart anatomy is one of the reasons for the existing conduits inadequacy. Here is proposed a confuser conduit model providing a stable uninterrupted flow. Development of a hemodynamically optimal type-size series of conduits would allow one to reduce the incidence of complications resulting from inadequate prosthesis design.
Subject(s)
Extracorporeal Circulation/instrumentation , Equipment Design , HumansABSTRACT
Some experimental results when studying self-sustained vibrations of the ball locking element for an artificial heart valve are presented. The sign-changing dependence of a ball drag coefficient upon the ball stroke has been shown to cause these vibrations. Undamped oscillations result in a considerable growth of the valve hydrodynamic resistance.
Subject(s)
Bioprosthesis/adverse effects , Heart Valve Prosthesis/adverse effects , Aortic Valve , Blood Pressure , Humans , Hydrostatic Pressure/adverse effects , Models, Cardiovascular , Prosthesis Design , Thrombosis/etiology , Vibration/adverse effectsSubject(s)
Aortic Valve , Erythrocyte Indices , Heart Valve Diseases , Heart Valve Diseases/etiology , Heart Valve Prosthesis/adverse effects , Hemolysis , Models, Cardiovascular , Thrombosis/etiology , Heart Valve Diseases/prevention & control , Humans , Surface Tension , Thrombosis/prevention & controlABSTRACT
A device designed for studying the motion kinematics of locking elements in the artificial cardiac valves is described. The principle of its operation is based on the photoelectric registration with subsequent electronic differentiation of the electric displacement signal. The length of measurable linear displacement is 0+20 mm. The amplitudinal-frequency characteristics of the differentiator is linear within the range of 0+120 Hz. The error of the displacement and speed error--not more than 5 per cent.
