Chapter 22: Thoracic Aneurysms and Aortic Dissection
The type of thoracic aortic aneurysm characterized by an outpouching of the aorta is
Aortic aneurysms can be either “true” or “false.” True aneurysms can take two forms: fusiform and saccular. Fusiform aneurysms are more common and can be described as symmetrical dilatations of the aorta. Saccular aneurysms are localized outpouchings of the aorta. False aneurysms, also called pseudoaneurysms, are leaks in the aortic wall that are contained by the outer layer of the aorta and/or the periaortic tissue; they are caused by disruption of the aortic wall and lead blood to collect in pouches of fibrotic tissue. (See Schwartz 10th ed., p. 785.)
Which of the following is the most common cause of thoracic aortic aneurysms?
D. Nonspecific medial degeneration
Nonspecific medial degeneration is the most common cause of thoracic aortic disease. Histologic findings of mild medial degeneration, including fragmentation of elastic fibers and loss of smooth muscle cells, are expected in the aging aorta. However, an advanced, accelerated form of medial degeneration leads to progressive weakening of the aortic wall, aneurysm formation, and eventual dissection, rupture, or both. The underlying causes of medial degenerative disease remain unknown. (See Schwarz 10th ed., p. 787.)
The most common complication of extensive repair for distal aortic aneurysms is
D. Left recurrent laryngeal nerve injury
Although spinal cord ischemia and renal failure receive the most attention, several other complications warrant consideration. The most common complication of extensive repairs is pulmonary dysfunction. With aneurysms adjacent to the left subclavian artery, the vagus and left recurrent laryngeal nerves are often adherent to the aortic wall and thus are susceptible to injury. (See Schwartz 10th ed., p. 802.)
Marfan syndrome is caused by an abnormality in which of the following proteins?