Abdominal Aortic Aneurysm Flashcards
What is an aneurysm?
What is ectasia?
increase in diameter greater then 50%
When the diameter is increased less than 50% above normal, it is called ectasia
What are the most common arterial aneurysms encountered?
infrarenal aortic aneurysms
3-7 times more frequent that thoracic aneurysms
What aneursyms are markers for abdominal aortic aneurysms?
What percent is this association?
popliteal aneurysms
8-35%, but up to 50% in patients with bilateral popliteal aneurysms
malpractice to not look to AAA when othe aneurysms are found
Screening is recommended for all first-degree relatives of any patients with an AAA. What is the chance of developing an AAA with a first-degree relationship?
20-25%
Describe the major causes & the pathogenesis of AAA
- 90% associated with atherosclerosis
- increased ratio of collagen to elastin in the walls
- elastin fragmentation, loss of smooth muscle causes elongation adn tortuousness
- inflammation (C-reactive protein and cytokines)
- latent infectious process
- deficiencies in antiproteases (such as alphi-1 antitrypsin – higher risk of rupture in Emphysema patients)
- uncommon causes include cystic medial necrosis, ehlers-danlos syndrome, and syphilis
What percent of AAAs are asymptomatic?
How are most of them found?
- 70-75% AAA are asymptomatic
- Most are found
- on routine physicla exam - pulsatile mass with a bruit
- imaging performed for another pathology
- unrelated abdominal operation
What are the clinical manifestations fo AAA?
- Back pain - aorta is retreperitoneal
- Flank pain
- abdominal pain - compression of intestines most commonly the duodenum
- abrupt onset of pain - 10/10 is characteristic of aneurysmal rupure
- ruptured AAAs make up ~25% of aneurysm findings
- majority of ruprures occur posterior-lateral on the left sideof the aorta (b/c vena cava & duodenum are on right)
- aorticaval fistula or aortioeneteric fistula may occur
- Classic presentation (black, flank, abdomen), hypotension, palpable pulsatile abdominal mass
What are the diagnostic steps to identifying an aortic aneurysm?
- Careful physical exam
- AAA ~5cm in thing person to be detected
- rarely palpable in obese patients
- X-rays: plain abdominal and lateral spine radiographs can establish the daignosis (67-75%) of AAA – but can’t tell size
- Ultrasound
- best option for continued observation
- Cat scan
- road map of what is going on with other arteries
- MRI
- long & expensive
- Aortography
- “gold standard” but rarely used
What is happening in the provided CT scans?
ruptured AAA
there is no distinct ring around it, showing that it is bleeding
What is trick about treating the aneurysm shown in the provided image?
the left renal branch is fine, but if you go in and just put a stent on the aneurysm, you will block branches to the right kidney & lose it
need a skilled surgeou
In what situations is an aortography recommended for AAA diagnosis?
- visceral ischemia
- occlusive ilio-femora vascular lesions
- occlusive pop-tibial vascular lesions
- severe hypertension throught to be caused by renal artery stenosis
- suspicion of horeshoe kidney
- presence of femoral and / or popliteal aneurysms
When do we operate on an AAA?
symptomatic
When it is 5 cm or greater
incrase in any size aneurysm by 1 cm in one year’s time
What is the standard of care for an AAA less then 4.5cm and the patient is asymptomatic
What if it is greater than 4.5 but less than 5?
repeat ultrasound in 6 months
if unchanged, then repeat in one year
If greater than 4.5 but less than 5, repeat ultrasound every 6 months
What are the treatment options to decrease the risk of AAA rupture?
- control blood pressure
- no heavy lifting or strenuous activity
- do not get constipated
- stop smokig
- ambulation
- platelet inhibition
What are the 3 surgical options for AAA?
- Full length midline (stem to stern)
- Wide transverse
- Oblique (retroperitoneum) - stays out of the abdomen
- graft mateial is either polyester (dacron) knitted or woven, or polytetrafluoroethylene (PTFE) “teflon”
- sew aneurysm sac over graft to preven aorticoenteric fistula
