Aortic valve replacement:
The indication of aortic valve replacement is based on the existence of a relevant hemodynamic narrowing (stenosis) or a failure of the valve. In principle, are available two different types of valve prosthesis namely mechanical and biological valve. Mechanical heart valves are formed in a metalic ring surrounded by tissue, on which are either fixed two valve wings(valve with double wings) by means of a movable hinge or it is positioned a flat disc (single-disc prosthesis). The two wings that mono-disc consist of have an extremely hard material containing carbon, which practically can be worn by the patient the whole life. To the great advantage of lifelong sustainability it opposes the disadvantage of the so-called thrombogenic valve. Due to the composition of synthetic valve it will result a coagulation of blood clotting compounds, which form a so-called thrombus and they will be deposited on the valve surface. The result is that the valve is not opened or will not close. On the other hand, the thrombi can reach the brain and cause a stroke or thrombotic occlusion of an artery which transport the blood to the extremities (hands and feet). This thrombogenic valve can be held in check only by the administration of an anticoagulant drug on a lifetime (Marcumar Sintrom). Biological heart valves consist essentially of a metal structure to which they are attached biological valve from a pig heart or from the tissue that surrounds the heart (pericardium). The advantage of heart valve lies in the fact that Marcumar anticoagulant should be administered only in the first three months after surgery. The disadvantage of these valves is the early degeneration that leads after 10 to 20 years to a new surgery (reoperation). Heart valves freestyle were introduced in the early 90 . For these prostheses from pig valve components they were left completely tight to the original device related to aortic wall. Blood flow behavior of this type of valve largely corresponds to that of a healthy human valve and it is superior to that of a biological valve. Based on this property and the fact that the valve does not even require the first three months after surgery Marcumar anticoagulant administration, this type of valve is used mainly in patients aged over 60 years. We distinguish two main techniques of implant: the subcoronarian implant and complete replacement of the aortic root.
Most patients with surgical indication are previously angiocoronarografic examined in order to identify possible coronary lesions. Surgical treatment consists either in valve reconstruction (preferable when possible) or in its replacement with a mechanical or biological prosthesis. After prosthesis, patients with increased risk for the occurrence of infectious endocarditis will follow prophylaxis antibiotic regimens in case of subsequent interventions with potential for bleeding (eg. dental extractions, surgery, etc.)
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