Pathogenesis of Aneurysms Basic Science 4/5/06

Which of the following statements regarding aneurysms is/are correct? An arterial aneurysm can be defined as a localized enlargement greater than 1.5 times its expected diameter. Intracranial cerebrovascular aneurysms and intraabdominal/ thoracic aneurysms share a significant number of common risk factors. Arterial ectasia refers to an enlargement of the artery < 50% of normal diameter. The primary significance of centrally located aneurysms relates to their risk of rupture. The primary significance of peripherally located aneurysms relates to their risk of thrombosis.

Which of the following statements regarding aneurysms is/are correct? An arterial aneurysm can be defined as a localized enlargement greater than 1.5 times its expected diameter. T Intracranial cerebrovascular aneurysms and intraabdominal/ thoracic aneurysms share a significant number of common risk factors. F, they are generally distinct. Arterial ectasia refers to an enlargement of the artery < 50% of normal diameter. T The primary significance of centrally located aneurysms relates to their risk of rupture. T The primary significance of peripherally located aneurysms relates to their risk of thrombosis. T

The propensity for aneurysms is considered multifactorial The propensity for aneurysms is considered multifactorial. Which of the following are pertinent? Age Degree of atherosclerosis. Genetic predisposition. Presence of post-stenotic arterial dilitation. Cholesterol level. Smoking history. Diabetes. Hypertension

The propensity for aneurysms is considered multifactorial The propensity for aneurysms is considered multifactorial. Which of the following are pertinent? Age T Degree of atherosclerosis. T Genetic predisposition. T Presence of post-stenotic arterial dilitation. T Cholesterol level. T Smoking history. T Diabetes. F Hypertension. T

Which of the following are considered to be at play in the pathogenesis of aortic aneurysms? There is a marked decrease in the amount of elastin in the media and adventitia of the vessel wall. Decrease type III collagen in the aortic media in certain familial aneurysms. Focal intimal thickening with encroachment of the lumen associated with atherosclerotic progression. Increased proteolytic activity of elastase and concurrent decrease in protease inhibitor concentration. Chronic inflammation in the arterial wall secondary to a preponderance of plama or T cells.

Which of the following are considered to be at play in the pathogenesis of aortic aneurysms? There is a marked decrease in the amount of elastin in the media and adventitia of the vessel wall. T Decrease type III collagen in the aortic media in certain familial aneurysms. T Focal intimal thickening with encroachment of the lumen associated with atherosclerotic progression. T Increased proteolytic activity of elastase and concurrent decrease in protease inhibitor concentration. T Chronic inflammation in the arterial wall secondary to a preponderance of plasma or T cells. T

Concerning the distribution of aortic aneurysms: Are most commonly located in the suprarenal aorta. Aneurysms involving the immediate infrarenal segment are also known as juxtarenal. Juxtarenal aneurysms are rare as the involved segment is mostly spared. Combined thoracic and abdominal aneurysms (ie. thoracoabdominal aneurysms) occur as frequently as 15% the time. Of those AAA with iliac artery involvement, up to 90% involve the common iliac arteries. The external iliac arteries are involved in almost 15% of AAA’s.

Concerning the distribution of aortic aneurysms: Are most commonly located in the suprarenal aorta. F, most are infrarenal sparing the segment immediatedly distal to the renal arteries. Aneurysms involving the immediate infrarenal segment are also known as juxtarenal. T Juxtarenal aneurysms are rare as the involved segment is mostly spared. T, see first question. Combined thoracic and abdominal aneurysms (ie. thoracoabdominal aneurysms) occur as frequently as 15% the time. F, they are a minority of cases at 2%. Of those AAA with iliac artery involvement, up to 90% involve the common iliac arteries. T, and 10% involve the hypogastrics. The external iliac arteries are involved in almost 15% of AAA’s. F, they are almost never involved.

Concerning the prevalence of aortic aneurysms: Overall prevalence in the general population at autopsy is roughly 8 - 14%. The prevalence of AAA in men is roughly twice that of women of the same age group. Whereas the prevalence of AAA continues to increase with age in men, the prevalence increases then peaks at 80 years old in women. Over the last thirty years, the prevalence of AAA has changed only slightly despite advances in diagnosis.

Concerning the prevalence of aortic aneurysms: Overall prevalence in the general population at autopsy is roughly 8 - 14%. F, only 1.8 - 6.6%. The prevalence of AAA in men is roughly twice that of women of the same age group. T Whereas the prevalence of AAA continues to increase with age in men, the prevalence increases then peaks at 80 years old in women. F, the inverse is true with a male peak at ~ 80 years old. Over the last thirty years, the prevalence of AAA has changed only slightly despite advances in diagnosis. F, it has roughly tripled in overall and age-specific prevalence.

Which of the following statements concerning AAA’s are False? The male-to-female ratio is roughly 2:1. White men have the highest prevalence, higher than black men or women. Of all the risk factors, smoking is the greatest. There is an approximate 5 fold increase in relative risk in a 1st degree relative of a person with AAA. Familial aneurysms affect patients at a younger age, and more frequently in women (compared to non familial).

Which of the following statements concerning AAA’s are False? The male-to-female ratio is roughly 2:1. F, it is closer to 8:1 White men have the highest prevalence, higher than black men or women. T Of all the risk factors, smoking is the greatest. T There is an approximate 5 fold increase in relative risk in a 1st degree relative of a person with AAA. F, the increase is on the order of almost 12 fold. Familial aneurysms affect patients at a younger age, and more frequently in women (compared to non familial). T

Concerning the distribution of thoracic aortic aneurysms: Are diagnosed at a rate of 1% per year. In 44% of cases coexist with an infrarenal aortic aneurysm. Occur with a male-female ratio similar to AAA’s. Up to 1/4 are segmental. Occur in familial clusterings with patients tending to be younger.

Concerning the distribution of thoracic aortic aneurysms: Are diagnosed at a rate of 1% per year. F, 5.9 per 100,000 per year. In 44% of cases coexist with an infrarenal aortic aneurysm. T Occur with a male-female ratio similar to AAA’s. F, ratio is 2:1 vs 8:1 for AAA’s. Up to 1/4 are segmental. T Occur in familial clusterings with patients tending to be younger. T

Regarding the progression of AAA’s: On average, aneurysms enlarge by 0.4cm per year. In 20% of cases, diagnosis is made after embolization from AAA to the lower extremities. The most critical factor determining risk of rupture is the maximal cross-sectional diameter. Risk of rupture is estimated at 40% for aneurysms >7cm. Following AAA rupture, the overall mortality rate is roughly 80-95%.

Regarding the progression of AAA’s: On average, aneurysms enlarge by 0.4cm per year. T In 20% of cases, diagnosis is made after embolization from AAA to the lower extremities. F, <5% The most critical factor determining risk of rupture is the maximal cross-sectional diameter. T Risk of rupture is estimated at 40% for aneurysms >7cm. F, 20% per year. Following AAA rupture, the overall mortality rate is roughly 80-95%. T

Regarding the progression of thoracic aortic aneurysms: Overall mortality is on the order of 95%. Descending arch aneurysms fare significantly worse than ascending or arch aneurysms. The expansion rate for arch aneurysms is 0.56cm per year.

Regarding the progression of thoracic aortic aneurysms: Overall mortality is on the order of 95%. T Descending arch aneurysms fare significantly worse than ascending or arch aneurysms. F, the inverse is true. The expansion rate for arch aneurysms is 0.56cm per year. T