Aneurysm arterial wall

Aneurysms can be repaired through reinforcement of the artery wall with a tube of woven PTFE or polyester. Replacement of sections of the artery can be done using a tube of porous PTFE. One remaining problem is the difference in elasticity between the woven and porous materials and the arteries themselves. 

Menkes syndrome (Menkes steely-hair syndrome) is a rare, X-linked recessive disorder in which infants have low levels of copper in serum and in most tissues except kidney and intestine, where the concentration is very high. They also have greatly reduced plasma ceruloplasmin levels. Hair of the affected infants has a characteristic color and texture (pili torti, twisted hair ). It appears tangled and dull, has an ivory or grayish color, and is friable. Weakness and depigmentation of hair and defects in arterial walls (leading to aneurysms) are explained by loss of activity of copper-dependent enzymes (Table 37-5). Cerebral dysfunction may be due to a disturbance in energy metabolism or neurotransmitter synthesis secondary to decreased activity of cytochrome oxidase and dopamine... 

In addition to intimal thickening, the arterial wall properties also change with age. Most measurements suggest that arterial elastic modulus increases with age (hardening of the arteries) however, in some cases arteries to become more compliant (inverse of elasticity) [Learoyd and Taylor, 1966]. Local weakening of the wall may also occur, particularly in the descending aorta, giving rise to an aneurysm, which, if ruptures, can cause sudden death. 

Traumatic aneurysms result from a direct injury to the arterial wall or to acceleration-induced shear. Cervical, cerebral or meningeal arteries can be af-... 

The arterial wall is composed of three layers. The outer serosal covering is the adventitia, the muscular middle layer is the media, and the inner lining is the intima. True aneurysms are distinguished from false or pseudoaneurysms based on which layers of the arterial wall are present in the aneurysm itself. In order to classify an aneurysm as being true, it must be comprised of all three layers. Pseudoaneurysms have any combination less than all three of the arterial wall components. 

Fibromuscular dysplasia (FMD) is an inherent arterial wall abnormality that classically affects the media of the renal arteries and can be associated with renal artery aneurysms. Several subtypes of FMD have been described and the disorder can affect other medium-sized vessels including the carotid, vertebral, brachial, and visceral arteries. For the angiographer, FMD has the classic beaded appearance often described as a string of pearls. Both aneurysms and dissections can be seen with this disorder. The treatment for FMD is angioplasty of the intraluminal webs, which results in significant remodeling. 

An aortic aneurysm is today a common condition often related to cardiovascular diseases. This condition is identified as a swelling of the aortic artery section led by the local weakening of its walls and systemic pressure (Johnston et al., 1991) (Fig. 11.19A). Thus, one can easily understand the danger and the risk of fatality associated with a burst on the artery wall, leading to a massive loss of blood. 

Arterial dissection is a common cause of ischemic stroke and TIA in young adults and may also occur in older people. Sometimes there is a predisposing cause (Schievink 2001 Rubinstein et al. 2005) (Table 6.4) but often there is no explanation. The artery may become occluded by the wall hematoma itself thrombosis and emboUsm may complicate occlusive or non-occlusive dissections, and aneurysmal bulging of the weakened wall may occur (O Connell et al. 1985). Arterial rupture is unusual. 

Congenital anomalies and aneurysms in the hepatic arteries are very rare. (129) Acquired aneurysms are the result of vessel wall damage, injuries or inflammatory processes. (I3l, 133, 136) Pseudoaneurysms may occur after acute pancreatitis and the formation of pseudocysts. (135) (s. tab. 39.5)... 

---