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Pathogenesis of Aneurysms

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.

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Pathogenesis of Aneurysms

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  1. Pathogenesis of Aneurysms Basic Science 4/5/06

  2. 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.

  3. 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

  4. 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

  5. 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

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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).

  13. 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

  14. 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.

  15. 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

  16. 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%.

  17. 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

  18. 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.

  19. 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

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