Aneurysm Flashcards
what is ananeurysm?
focal dilation of an artery >50% of the normal diameter of the vessel
what size confirms an aneurysm in aorta, common iliac and popliteal?
aorta = >3cm
common iliac = >2.5cm
popliteal = >1cm
what is a true vs false aneurysm?
true = involves all 3 layers of the arterial wall, blood contained within all 3 layers false/pseudoaneurysm = vessel wall is damaged so blood leaks out and is contained within surrounding tissues
how can aneurysms be classified by morphology?
fusiform (vessel is symmetrically swollen)
saccular/berry (swells out the way)
what should you look for in a popliteal aneurysm?
other aneurysms
commonly have one in other politeal and an AAA
most AAA are what shape?
fusiform
congenital causes of aneurysm?
connective tissue disorder (marfans, ehlers danlos etc)
PKD associated with cerebral aneurysms
acquired causes of aneurysm?
vasculitis
infectious (syphilis, TB etc)
most are idiopathic (possibly due o to collagenase imbalance)
trauma
modifiable risk factors?
smoking
hypertensino
high cholesterol
obesity
non-modifiable risk factors?
male gender age family history ethnicity known coronary artery/peripheral vascular/carotid/cerebrovascular disease)
which aneurysms are most likely to rupture?
risk increases with size
mortality of AAA rupture?
75% wont make it to hospital
25% of those who make it to hospital wont make it
what can give better chance of making it to hospital in AAA?
if it ruptures into retroperitoneal space meaning its contained
(rapidly fatal if it ruptures into the intra-peritoneal space as it can just keep bleeding)
what other problems can an aneurysm cause?
thromboembolic events
local pressure effects (mainly in politeal)
why does risk of rupture increase with size?
law of la place
larger vessel radius = more tension required to withstand internal fluid pressure, so when artery wall expands, the wall gets thinner but the tension on the wall increases, increased tension leads to more expansion and greater risk of rupture
how is AAA diagnosed?
men >65 are screened via abdominal USS
do USS if suspicious of asymptomatic USS
do CT angiogram if symptomatic or suspected rupture
most are found incidentally however
where do you examine for an AAA?
palpate for expansile mass above the umbilicus (AA bifurcates at umbilicus level)
what symptoms might you get from AAA?
usually pain or pulsatile feeling but usually asymptomatic
how is asymptomatic AAA managed?
stop smoking and reduce cardio risk (loose weight, treat hypertension etc)
close surveillance depending on size or consider surgical repair if large enough
when is surgical repair considered in asymptomatic AAA?
if >5.5cm or >4cm and grown >1cm in past year
how is asymptomatic AAA surveillanced?
if 3-4.4cm = yearly USS
if 4.5-5.4cm = 3 monthly USS
>5.5 = surgery
workup for elective repair in asymptomatic AAA?
must do CT angiogram to know specific location
assess fitness for surgery with bloods, ECG, ECHO, pulmonary function tests, frailty score and METS
how might a ruptured AAA present?
collapse
hypotension
sudden onset abdo pain radiating to back (or might just be felt in back)
expansile abdo mass +/- tenderness
how else might a AAA present?
can present like renal colic (esp in men >50)
retroperitoneal fluid can cause flank pain
so beware of “renal colic” in men >50
how is a ruptured AAA managed?
surgical emergency
ABCDE (get large bore IV access, send bloods, fluid resuscitation with permissive hypotension)
arrange urgent CT imaging (try and stabilise enough to get a CT before surgery)
refer to vascular surgery for open or endovascular repair
what is permissive hypotension?
as long as patient is conscious (enough blood getting to brain to maintain consciousness) then you dont need to push blood and fluids in to increase BP
maintain systolic BP 70-80mmHg
if theyve made it to hospital then theyve probably formed a tamponade or clot which is keeping the bleeding at bay, if you pump lots of bloods/fluids in you could disrupt this causing massive bleed
what happens in open repair?
laparotomy (open them up)
aorta clamped proximal and distal to aneurysm
aneurysm cut open and a graft inserted into aorta, aorta wall then sewn back up around graft
what happens in endovascular repair (EVAR)?
repairs artery from inside using a stent graft
access from femoral artery and series of wires etc fed up into aorta under X ray guidance and stent expanded inside aorta
good for complex cases involving coeliac axis, mesenterics etc as can cover a few vessels
complications of EVAR?
mainly endoleak
blood leaks through or around the graft/stent meaning the aneurysm sac can refill and rupture
might settle on it own or may need another surgery
4 types of endoleak?
1 = leak due to incomplete seal 2 = back bleeding from arteries entering sac 3 = graft dysfunction 4 = porous graft material
which is better open repair or EVAR?
neither strictly better
EVAR better survival at 6 months
open repair better survival at 8 years