Abdominal Aortic Aneurysm

What are the monitoring recommendations for patients following an EVAR?

- CT scans at 1 month and 12 months after the procedure (Most endoleaks following repairs tend to present early.)

What are 3 inherited conditions are known to be associated with aneurysms?

- Marfan syndrome - Ehlers-Danlos syndrome - familial thoracic aneurysm and dissection syndrome (TAAD)

What are 2 of the most important risk factors associated with AAA formation?

- age - family history

What 2 things are the best predictors of rupture?

- aneurysm size - symptoms

What are 4 things that can weaken arterial walls?

- collagen defects - inflammatory conditions - immune responses - atherosclerotic changes

A patient should have an open or endovascular intervention for AAA under what conditions?

- diameter: >5.5 cm in men, >5.0 cm in women - rapid growth: >0.5 cm in 6 months - symptomatic AAA: (pain or distal embolism)

The open approaches to surgery are associated with what 2 things?

- extensive dissections - significant perioperative fluid shifts

Name 5 nonmodifiable risk factors of AAA.

- older age (age >50 for men, >60 for women) - male sex (4x increased risk for M vs. F) - family history - race (more common in whites) - height

What are the US Preventative Service Task Force screening recommendations for AAA?

- one-time ultrasound screening for: men age 65-75 who have ever smoked - selective screening for: men age 65-75 who have never smoked

AAA repair options include which 2 procedures?

- open aneurysmectomy - endovascular aneurysm repair (EVAR)

What kind of approach is EVAR (endovascular aneurysm repair)?

- percutaneous approach

What are 4 potential complications of an AAA?

- rupture - thrombosis - distal embolization - increased risk for arterial aneurysms at other sites

The current recommendations for open or endovascular interventions for AAA are based on what 3 things?

- size - growth rate - symptoms

Name 4 modifiable risk factors of AAA.

- smoking - hypertension - elevated cholesterol levels - obesity

What are 3 risk-reduction strategies that have been identified to decrease aneurysm ruptures?

- smoking cessation - control of hypertension - control of hypercholesterolemia

What should occur for a small, asymptomatic AAA (4-5 cm)?

- surveillance (repeat physical exams and follow-up ultrasounds every 6 months)

What 2 approaches exist for open surgery?

- trans-abdominal approach - retroperitoneal approach

What is the reported 30-day mortality after EVAR? What is the average hospital stay?

1% Average hospital stay: 3 days

Describe the recommended surveillance intervals for AAA with ultrasonography in regard to size.

2.6-2.9 cm: re-examine in 5 years 3.0-3.4 cm: every 3 years 3.5-4.4 cm: every year 4.5-5.4 cm: every 6 months

A re-intervention rate of what percent is seen following open AAA repairs?

20% Therefore, CT monitoring is recommended at 5-year intervals following open AAA repairs.

In general, what percent of patients require secondary interventions within 6 years following EVAR?

20-30%

What is the average reported 30-day mortality for open AAA repair? What's the average hospital stay?

4-5% Average hospital stay: 9 days

For individuals who are fortunate enough to reach the hospital with a ruptured AAA, what is the reported mortality rate?

50-70%

When an AAA rupture occurs, what is the overall mortality rate?

85-90%

Describe the estimated rupture risk of AAA based on size.

<4 cm: (0% per year) 4-5 cm: (0.5% per year) <5.5 cm: (<1% per year) 5-6 cm: (3-15% per year) 6-7 cm: (10-20% per year) 7-8 cm: (20-40% per year) >8 cm: (30-50% per year)

What is considered rapid growth of an AAA, and is an indication for repair?

>0.5 cm growth in 6 months

AAA greater than what diameter should be considered for repair in men and women due to the risk of rupture?

>5.5 cm in men >5.0 cm in women

What is a Type 5 endoleak? What's another name for it?

A Type 5 endoleak, or "endotension": An aneurysm sac that remains pressurized, without visible endoleaks.

Patients diagnosed with AAA should have what included in their PE to look for aneurysmal disease in other anatomic locations?

A thorough pulse examination

Define aneurysm.

An aneurysm exists when a segment of an artery increases in size to more than 50% of the normal diameter (ie, >150% the size of the native artery).

What is aneurysm formation caused by?

Aneurysm formation is caused by conditions that cause weakening of the arterial walls, including collagen defects, inflammatory conditions, immune responses, and atherosclerotic changes.

How do arterial aneurysms develop? What are 3 things that happen?

Arterial aneurysms develop as the result of a degenerative process involving the arterial wall. The process is associated with: - infiltration of the arterial wall by lymphocytes and macrophages - destruction of the elastin and collagen in the media and adventitia of the artery - loss of smooth muscle cells, resulting in thinning of the arterial wall

Question 5: For which of the following patients is nonoperative management most appropriate? A A 65-year-old otherwise healthy woman with a 5.2 cm AAA B A 96-year-old man with severe dementia and a 6-cm AAA. The patient has been a long-term resident of a chronic care facility due to inability to care for himself secondary to his dementia C A 60-year-old man with a 5.3 cm AAA who presents with unexplained back pain over the past 24 hours. No other causes of back pain can be identified D A 63-year-old man with 5.4 cm AAA and new onset of painful ecchymoses in the tips of several toes in both feet E A 63-year-old man with a known AAA that is under surveillance. His aneurysm has grown from 4.5 to 5.4 cm over the past 6 months

B A 96-year-old man with severe dementia and a 6-cm AAA. The patient has been a long-term resident of a chronic care facility due to inability to care for himself secondary to his dementia. AAA repair for a man with a 6-cm AAA may be medically indicated; however, given his limited level of function and poor quality of life, AAA repair is not likely to improve his quality of life. It is difficult to justify AAA repair for this individual given that the indications for repair are better in the other individuals described.

Question 6: Which of the following statements is true regarding EVAR? A With introduction of EVAR, the minimal size for recommending repairs have changed B EVAR is contraindicated in individuals with aneurysms >10 cm C EVAR repair is associated with higher rates of leakage within the first year in comparison to open repairs D EVAR is contraindicated in individuals with aneurysms involving the iliac arteries E EVAR should not be performed in individuals who can tolerate open repairs

C EVAR repair is associated with higher rates of leakage within the first year in comparison to open repairs The endoleaks associated with EVAR are generally present within the first year after the procedures; whereas, complications related to open aneurysm repairs tend to occur later. There is no size limitation to EVAR. The introduction of EVAR has not changed the size criteria for recommending aneurysm repairs.

Question 4: Which of the following statements is true regarding EVAR? A EVAR is associated with higher peri-procedural complication rates in comparison to open repairs B EVAR can be applied to 100% of the patients with AAA C Most EVAR complications do not require open interventions D EVAR is an inferior approach for patients with prior abdominal operations E EVAR is no longer recommended due to its peri-procedural complications

C Most EVAR complications do not require open interventions Most EVAR complications are amendable to percutaneous treatments, with only 2% to 4% of patients requiring open interventions for complications. EVAR is associated with lower postoperative complications and shorter hospitalization when compared to open repairs. EVAR is a better approach than open repairs for patients with extensive history of prior abdominal operations. Currently, EVAR outnumbers open AAA repairs in the United States.

Question 3: Which of the following is a known complication associated with AAA? A Early satiety B Small bowel obstruction C Painful discoloration of the great toe D Hematuria E Hematochezia

C Painful discoloration of the great toe Painful discoloration of the toes can occur as the result of embolization of aneurysm contents to the distal arteries. This is referred to as the "blue toes syndrome" or "trashed feet."

Question 2: For the patient described in question 1, when is continued nonoperative treatment most reasonable? A The patient complains of back pain without other identifiable causes. His AAA is now measuring 5.2 cm in diameter B The patient's aneurysm has increased to 4.8 cm over 2 years; however, he presents with painful ischemic changes in several toes in both feet C The aneurysm measures 5.3 cm in diameter at follow-up 3 years after surveillance began D The patient's aneurysm grew from 4.6 cm to 5.5 cm over a 6-month interval E The patient presents with sudden onset of back pain with CT demonstrating retroperitoneal fluid around the AAA

C. The aneurysm measures 5.3 cm in diameter at follow-up 3 years after surveillance began. AAAs measuring less than 5.5 cm and that are asymptomatic in men can be monitored. Symptomatic AAA often represents impending rupture and is an indication for repair. Similarly AAA that has rapid growth defined as >0.5 cm growth over a 6 month period should also be repaired. Patients presenting with "blue toe syndrome" related to their AAA should undergo AAA repair, as this syndrome is related to distal embolization from the aneurysm. Patient described in choice "E" has a leaking AAA that should undergo emergency repair.

What kind of monitoring is recommended following open AAA repairs?

CT monitoring at 5-year intervals

The control of what 3 factors seem to be beneficial in reducing the risk of AAA expansion?

Control of: - hypertension - hypercholesterolemia - coronary artery disease

Question 1: A 61-year-old man is found on physical examination to have an asymptomatic AAA. Ultrasound evaluation reveals that the AAA measures 4 cm in diameter. Which of the following is the best surveillance strategy for his AAA? A Observation with ultrasound evaluation every 3 years B Ultrasound evaluation only when the AAA becomes symptomatic C Ultrasound evaluation every 6 months D Ultrasound evaluation every year E CT angiography every 6 months

D. Ultrasound evaluation every year Explanation: The current recommendations for ultrasound surveillance of AAA are: 2.6 to 2.9 cm re-examine in 5 years; 3 to 3.4 cm re-examine every 3 years; 3.5 to 4.4 cm re-examine yearly; 4.5 to 5.4 cm re-examine every 6 months.

Most experts recommend elective AAA repairs when the aneurysm reaches what diameter in men and women?

Elective repairs are recommended for an aneurysm that reaches: 5.5 cm in men 5.0 cm in women

What are endoleaks?

Endoleaks are persistence of blood flow outside the endograft following EVAR (endovascular repair).

How is the percutaneous approach for EVAR done? Explain the general procedure of an EVAR.

Gained through a puncture in the femoral artery. Under image-guidance, covered stent grafts are placed into the aorta, and anchored to the normal aorta above the aneurysm, and to the iliac arteries below the aneurysm.

Given the lethal nature of ruptured AAA, it is most important to do what for patients?

Identify the patients with high-risk AAA for elective repairs to prevent ruptures.

Approximately 85% of AAAs are located where?

In the infrarenal aorta

Name the 3 layers of the arterial wall.

Innermost layer: tunica intima (tunica interna) Middle layer: tunica media Outermost layer: tunica adventitia (tunica externa) The innermost layer, the tunica intima, is simple squamous epithelium surrounded by a connective tissue basement membrane with elastic fibers. The middle layer, the tunica media, is primarily smooth muscle and is usually the thickest layer. The tunica adventitia is connective tissue with varying amounts of elastic and collagenous fibers.

What is a Type 4 endoleak?

Leaking between the interstices of the graft fabric.

AAA is more common in which sex?

Men

The prevalence of AAA increases after what age in men and women?

Men: after age 50 Women: after age 60-70

What's the reason for continuing surveillance rather than repairing an AAA that's 4-5 cm?

Randomized controlled trials comparing observation vs. elective repairs of small, asymptomatic AAA (4-5 cm) showed that elective repairs were associated with: - increased 30-day mortality, and does not improve patient survival over a 20 month period

When should surveillance for AAA be utilized?

Small aneurysms (3.0-5.4 cm) in men when identified should be monitored for size changes by ultrasonography.

The EVAR approach is done for what percentage of AAA repairs in the US?

The EVAR approach is done for more than 75% of all AAA repairs in the US.

True or false: A patient with suspected ruptured AAA associated with hemodynamic instability should undergo exploration and attempted repair, rather than delaying the repair for confirmatory CT scan.

True

True or false: Based on arterial anatomy and technical limitations, some patients are not candidates for EVAR.

True

True or false: The majority of the re-interventions following EVAR are percutaneous, with only 2-4% of the patients requiring open secondary interventions.

True

True or false: Even if intervention for a pt's aneurysm is not currently indicated based on the size and asymptomatic nature, it is important to educate the pt regarding risk reduction strategies to minimize AAA expansion and rupture.

True

True or false: Most endoleaks following repairs tend to present early.

True

True or false: Patients require close follow-up after both open AAA repairs and EVAR.

True

True or false: Procedure-related cardiovascular, pulmonary, and infectious complications rates are significantly lower following EVAR in comparison to open repairs.

True

True or false: The risk of AAA formation is greater in men than women.

True Men:Women ratio is 4:1

True or false: The majority of individuals with AAA do not have symptoms until rupture occurs.

True Therefore, screening can be valuable in identifying the disease in high-risk populations, (such as older men and individuals with a family history of AAA).

What is a Type 1 endoleak?

Type 1 endoleak: Caused by inadequate sealing at either the proximal or distal endograft attachment sites.

What is a Type 2 endoleak?

Type 2 endoleak: Caused by blood flow into the aneurysm sac from patent branch vessels (such as the inferior mesenteric artery and lumbar arteries).

What is a Type 3 endoleak?

Type 3 endoleak: Caused by a defect in the fabric of the endograft, or leakage between separate graft components deployed.

How are size changes for AAA monitored?

Ultrasonography

In what race is AAA most common?

Whites

The risk of AAA rupture is higher in which sex?

Women

What is the most common reason for secondary intervention following EVAR?

endoleaks

AAAs are palpable where?

the epigastrium

Iliac aneurysms are palpable where?

the infraumbilical locations (below the umbilicus)