12 Key and Core Catalog With a mechanical key system, the level of security is determined by masterkey control. A masterkey system enables facilities of any size to manage the building by defining access by person and by area in increasing levels of complexity. Since BEST invented the standard for masterkey systems, there is no
When they occur in the upper part of the aorta, they are called thoracic aortic aneurysms. Aneurysms can occur anywhere in the thoracic aorta, including the ascending aorta near the heart, the aortic arch in the curve of the thoracic aorta and the descending aorta in the lower part of the thoracic aorta.
A thoracic aortic aneurysm is a weakened area in the upper part of the aorta. The aorta is the major blood vessel that feeds blood to the body. A thoracic aortic aneurysm may also be called thoracic aneurysm and aortic dissection (TAAD) because an aneurysm can lead to a tear in the artery wall (dissection) that can cause life-threatening bleeding.