Vascular aneurysms Flashcards
At what diameter does an abdominal aneurysm occur?
> 1.5 times normal
>3 cm
where do most AAA occur?
infra renal
true or false
most AAA are true aneurysms
True
what layers are usually involved in pseudo aneurysms?
adventitia
connective tissue
what are the 4 main etiologies of AAAs?
Degenerative
Inflammatory
Traumatic
Infections
how do degenerative AAA form?
atherosclerotic AAA
associated w/matrix metalloproteinases
where are matrix metalloproteinases in the vessel of degenerative aneurysm?
the media
how to inflammatory AAA form?
exaggerated inflammation leading to fibrotic reaction around the aneurysm the can encase the surrounding structures
what are inflammatory AAAs associated with?
ureteral obstruction
how are infectious AAAs formed?
may be caused by primary infection of arterial wall or foreign bodies (prior vascular repair)
what bacteria are associated w/infectious AAAs
Salmonella Staph Candida Aspergillus Mycobacterium tuberculosis Treponema pallidum
what are the biggest RFs for AAA development?
smoking increased age (over 70) male family hx concurrent aneurysms HTN HLD CAD
what are 2 protective factors for AAA
diabetes
DVT
what are risk factors for rupture?
female decreased FEV1 large initial aortic diameter current smoker uncontrolled HTN
at what diameter does risk for rupture exponentially increase?
5.0 cm (1-11%)
what is the screening recommendation for AAA
U/S screening in men or women 65-75 years w/hx of tobacco use
or
U/S screening in first degree relative of Pts w/AAA, do at age 65-75 or 75 and older and in good health
is there a higher incidence of peripheral aneurysms in those with AAA?
yes
How can AAAs cause distal ischemic symptoms
atheroembolism
acute thrombosis of AAA can cause acute lower body ischemia (very rare)
what is the best imaging test for AAA?
U/S
almost 100% sensitivity and specificity
not good for detecting rupture
what SBP is the goal for a ruptured AAA?
70-90 mmHg
permissive hypotension
when do you repair a AAA besides rupture?
diameter > 5.5 cm
> 5 mm growth in 6 months or >1 cm growth in 1 year
symptomatic abdominal pain (emergent repair)
signs of embolism
mycotic aneurysm
what is a relative indication for repair?
saccular AAA
what are the disadvantages of endovascular repair?
higher rate of reintervention need long term follow up and imaging no difference in mortality rate 2-3 years after intervention high cose not for everyone
what do you need to do an EVAR?
10-15 mm “landing zone in normal infra renal aorta and iliac artery
less than 25% circumferential thrombus in “landing zone”
no significant tortuosity in infrarenal landing zone
large enough iliac arteries for delivery sheaths
how big do the iliac arteries have to be to do an EVAR
6-7 mm w/o significant plaque burden
what are the warning signs of colon ischemia?
early post op diarrhea, melena, hematochezia, leukocytosis, metabolic acidosis/lactate, hypotension
treatment for colon ischemia includes
sigmoidoscopy aggressive IVF broad spec abx bowel rest ex-lap if full thickness bowel ischemia
how does a graft infection present?
“herald bleed”
inflammation or bleeding into bowel on CT
direct visualization of graft material on EGD
how to treat graft infection?
removal of entire graft
wide debridement of affected tissues
in situ recon or extra anatomical bypass (staged)
what are options for in-situ reconstruction of graft infection?
rifampin soaked or silver coated polyester grafts
cryopreserved arterial allograft
saphenofemoral vein allograft
how to treat a stable patient with graft infection?
staged axillary bifemoral bypass then 24-48 hrs laters RTOR to explant infected graft
if doing a bypass for graft infection what must you make sure to do?
oversew aortic stump in 2 layers and cover with mental patch to prevent stump break down and blow out
what is a type I endoleak?
failure to achieve satisfactory seal at proximal (type Ia) or distal zone (1B)
aneurysmal sac is not excluded
what is a type II endoleak?
continued retrograde filling of aneurysmal sac by lumbar branches or IMA
what is a type III endoleak?
failure of individual component or of seal between components of graft system
aneurysmal sac not excluded
what is a type IV endoleak?
leakage through the porous material of the graft (rare)
what is a type V endoleak?
persistent growth of aneurysmal sac without detectable leak (endotension)
which types of endoleaks do you have to repair?
Types I and III because the sac is not excluded
how do you repair a type II endoleak?
requires repair if there is continued aneurysm sac expansion
embolization of back bleeding branches or direct aneurysm sac puncture w/injection of thrombotic agents
what is the most common endoleak type?
type II
when do you follow up with someone with 2.5-2.9 cm AAA
10 years
when do you follow up with someone with 3.0-3.9 cm AAA
3 years
when do you follow up with someone with 4.0-4.9 cm AAA
1 year
when do you follow up with someone with 5.0-5.4 cm AAA
6 months
what is the follow up after an EVAR?
baseline imaging at 1 month post-op with contrast enhanced CT and duplex U/S
if no leak after 1 month of EVAR when is the next follow up?
repeat imaging at 12 months
if there is an endoleak 1 month after EVAR when is the next follow up?
repeat imaging at 6 months
should accessory renal arteries be preserved when possible?
yes
what approach is helpful with a horse shoe kidney?
retroperitoneal
allows mobilization of the kidney anteriorly
do not divide the isthmus of the horseshoe kidney
during an open AAA repair, if an asymptomatic colon mass or cholelithiasis is found should it be taken out?
no
if during an open AAA repair you injure the bowel how do you manage it?
repair the enterotomy
consider aborting case and closing abdomen, return at later date to repair aneurysm
management of bowel injury after graft implantation
repair enterotomy
copious irrigation
consider IV abx
how to manage a ureteral injury during open AAA
IV methylene blue can help ID injury
intra op urology repair
how to manage a venous injury during open AAA
can be from clamp injury or dissection
manual compression proximal and distal
division of ipsilateral iliac artery may be needed to visualize and repair injury
how to manage distal embolization after open AAA
can be from clamping disease vessels or failure to adequately flush prior to completion of an anastomosis
how to manage femoral artery injury during EVAR
get open exposure of artery
primary repair if possible
complete femoral endarterectomy w/patch angioplasty if needed
how to manage iliac artery injury during EVAR
covered stent placement for perforation if needed
consider balloon occlusion and open repair if needed
how to manage groin hematoma after EVAR
localized pressure
reverse coagulopathy
arterial duplex to assess for active flow or pseudoaneurysm
how to manage a femoral pseudoaneurysm
localized pressure
reverse coagulopathy
arterial duplex to assess neck, if narrow can do thrombin injection, if short/wide or clinically unstable or skin necrosis needs open repair
