Abdominal Aortic Aneurysm

Where is the most common site for an AAA?

*infra-renal* aorta - below origin of the renal arteries

Aneurysm - define

*irreversible* dilation of an artery at least 1.5 times its normal diameter

What is the average growth rate for aneurysms per year?

0.4 cm/yr (or less)

What should we be rapidly doing to treat a patient for a suspected ruptured AAA?

1. 2 large bore peripheral IVs 2. baseline labs 3. foley catheter 4. type and cross 5. notify attending 6. notify vascular attending 7. call the OR

What are some indications for repair of an AAA? (4)

1. AAA > 5 cm, those > 80 yo should wait > 6 cm 2. ruptured AAA 3. rapidly expanding (> 0.5/year) 4. evidence of distal embolization

What are some etiologies of a dissecting aneurysm? (4)

1. HTN 2. Marfan's syndrome 3. Blunt trauma 4. during cannulation w/ coronary bypass

What are some possible complications associated with AAA surgery? (7)

1. MI 2. Renal failure 3. Colon ischemia 4. Spinal cord ischemia 5. Aortoenteric fistula 6. Graft infection 7. Impotence

What vessels are clamped during an AAA repair?

1. R & L common iliac arteries 2. Aorta

What are 3 common bacterial causes of a mycotic aneurysm?

1. Syphilis 2. Salmonella 3. Staphylococcus

What is the normal diameter of the abdominal aorta?

2 cm

Studies have shown that repair of an aneurysm greater than ______ cm prolongs patient survival.

6

What is the mortality rate for a ruptured AAA?

90%

At what size does the AA become an aneurysm?

>/= 3 cm

What is the most common *type* of aneurysm?

Degenerative

How can AAA surgery lead to renal failure?

Hypotension due to blood loss can lead to acute tubular necrosis - blood loss from rupture - decreased BF to kidney from clamps during surgery

What is Blue Toe Syndrome?

It occurs when the patient presents with discolored toes (blue/purple) due to embolization somewhere in the body

What is the number 1 cause of death in patients undergoing elective AAA repair?

MI

If a patient has an AAA where else should you suspect they may have another aneurysm?

Popliteal artery - be sure to check for the popliteal pulse

If a patient has CAD and they also want to undergo an elective AAA repair, what needs to be done first?

Preoperative coronary revascularization or at least a cardiac work up

How do patients with a dissecting aneurysm describe their pain as?

TEARNG

What is Laplace's Law

Tension = pressure x diameter

T or F: Endovascular grafts have been shown to increase patient survival with repair of an AAA.

True

T or F: Vascular disease is a BODY WIDE process.

True

What is the imaging procedure of choice for an AAA?

U/S

How should we unclamp the vessels post AAA repair? Why?

Unclamp one leg at a time - b/c severe hypotension may occur - b/c lactic acid and wastes would rush throughout the body and possibly cause an arrhythmia or death (metabolic wash out)

When does an aneurysm rupture?

When the stress on the arterial wall exceeds strength of the arterial wall - like a balloon popping

If a patient with a known aneurysm presents to the ER with syncope and abdominal pain, but is stable what should you send them for?

an emergent CT scan - IV contrast only

What is a mycotic aneurysm?

an infected aneurysm

At the induction of anesthesia in a patient with a ruptured AAA what should you be prepared for?

be ready for BP crash

What symptom is evidence of colon ischemia post AAA surgery?

bloody diarrhea

What might we see on a plain x-ray of a patient with a AAA?

calcification of the aneurysm

Why do pregnant women get aneurysms?

due to the hemodynamic stress of pregnancy - it is reversible... (which goes against the definition of an aneurysm..)

How are AAA usually found?

incidentally on PE or imaging study that was performed for other reasons

True aneurysm - define

involves all layers of the arterial wall

False aneurysm - define

involves only a portion of the vessel wall

What vein crosses over the abdominal aorta to empty into the IVC?

left renal vein - this is an important landmark - DO NOT SACRIFICE IT

Are AAA more common in males or females?

males

What is a traumatic aneurysm?

occurs when there is a focal defect in the arterial wall with local bleeding contained by surrounding tissues

Define a dissecting aneurysm

occurs when there is a longitudinal splitting of the layers of the arterial wall

Anterior spinal syndrome - define

paraplegia that follows surgery to the lower thoracic aorta in which the greater medullary artery of Adamkewisc is disrupted - PERMANENT

A patient who presents to the ER with the complaint of syncope and severe abdominal pain has a what until proven otherwise?

ruptured AAA

Which artery is the most common to have an aneurysm in a pregnant woman?

splenic artery aneurysm - very hard to find on imaging

If a patient has a known aneurysm and presents to the ER w/ syncope and abdominal pain and is clearly unstable what should you do?

take them directly to the OR

What is a CT/CTA helpful for evaluating in a patient with an AAA?

the AAA relation to the renal and iliac arteries

What type of patient should we without question give IV fluids to with a ruptured AAA?

those who are unstable! - if they are awake you should hold off

Why would we get an MRI/MRA on a patient with an AAA?

to evaluate the aneurysm characteristics for consideration of endovascular repair

How do aneurysms of pregnancy usually present?

with rupture and shock