Aortic Aneurysms Flashcards
define aneurysm
focal
1.5x increase in normal diameter
define ectasia
diffuse dilatation of an artery
increase in diameter >50%
define arteriomegaly
diffuse enlargement of an artery
define pseudo aneurysm
frequently due to trauma
define true aneurysm
incorporates all three layers of the vessel
associates aneurysms that aortic aneurysms may hev
aortoiliac - 41%
femoro-popliteal - 15%
associated medical conditions with aortic aneurysms
carotid artery stenosis
smoker
male
HTN
reasons aortic aneurysm develops (aetiology)
- atherosclerosis
- cystic medial necrosis
- dissection
- Ehlers-danlos syndrome
- syphilis
- familial associated (Lysol oxidase syndrome)
- degenerative
- mycotic
- inflammatory
how can aortic aneurysm be degenerative
decrease in elastic and collagen in arterial wall
elastic becomes fragmented - arterial elongation and dilatation
increase in the collagenase and elastase activity
how can aortic aneurysm be mycotic
degradation of media and intimal layers by S. cocci and E. coli
Laplace’s law
tension = pressure x radius
clinical presentation of aortic aneurysm
asymptomatic: 70-75%
symptoms: early satiety, abdominal flank or back pain
abrupt onset of pain = rupture or expansion of aneurysm
frequently incidental discovery
ruptured aneurysms locations
usually occurs postero-laterally
can rupture in vena cava creating aorta-caval fistula
ruptured aneurysms locations
usually occurs postero-laterally
can rupture in vena cava creating aorta-caval fistula
occasionally can rupture anterior which is rally fatal
limitation of arteriography for aortic aneurysm diagnosis
cannot determine aneurysm size because of mural thrombus
indications for obatining an ateriogrpahy
suspicion of visceral ischaemia
occlusive disease of iliac and femoral arteries
severe HTN, or impair renal function
horseshoe kidney
suprarenal of TAAA component
femora-popliteal aneurysms
ways that ultrasound for aortic aneurysm is helpful
establishes diagnosis easily
accurately measures infrarenal diameter
widely available, quick, no rick, cheap
ways that US for AA is not helpful
difficult to visualise thoracic or suprarenal aneurysms
difficult to establish relationship to renal arteries
technician dependant
ways that CT scan for AA is helpful
reliable and reproducible
can image entire aorta
can visualise relationship to visceral vessels
most useful
ways that CT scan for AA is not helpful
longer to obtain and more expensive
requires contract agent which can cause renal toxicity
MRA (magnetic resonance angiography) for AA
now widely available
more expensive than CT and US
no contract agent needed
spacial resolution less than CT
complications for AAs
thrombosis
distal embolisation
rupture
how high is risk of rupture in AA
23.4% of aneurysms 4-5cm will rupture
what increases likelihood of rupture
patients with COPD and HTN have increased risk
likelihood of survival of rupture
half die before reaching hospital
an additional quarter die before repair
how to reduce mortality associated with surgical repair
endovascular techniques are reducing surgical mortality
indications for treatment of AA
infrarenal aneurysm >5cm without comorbid medical conditions
repair smaller aneurysms f rate of enlargement is larger than expected
repair all symptomatic aneurysms
indications for treatment in patients with AA and comorbid conditions
wait until risk of repair and rupture are equal (usually about 6cm)
standard surgical repair for AA
replace diseased aorta with synthetic material
requires 7 day hospital stay
potential complications in standard repair of AA
cardiac
renal
respiratory
bowel ischameia
spinal ischaemia (rare)
EVAR stands for
endovascular aneurysm repair
what is EVAR
percutaneous access through groin with expandable prosthesis under fluoroscopic guidance
why do EVAR
significantly reduced m&m
long term result good in selected patients
life long surveillance recommended
hospital stay 2 days
