Chap 130-133 Abdominal Aortic Aneurysm Flashcards Preview

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Flashcards in Chap 130-133 Abdominal Aortic Aneurysm Deck (62):
1

What is definition of aneurysm?

50% increase in d compared to expected size (SVS)
>3cm
50% increase relative to adjacent normal size

2

what is ectasia?

intermediate stage of enlargement <50%

3

what is arteriomegaly?

diffuse continuous enlargement of multiple arterial segments dilated to >50% of normal

4

what is most significant RF for development of AAA? what are other RF?

smoking

age, maleness
famhx, white, DM
HTN increase rupture risk

5

What % of men >65 have AAA? women?

5%
1.7%

6

What % of TA have AAA?
What % of AAA have TA?
What % have iliac involvement?
what % of 1st degree family members have AAA?

50%
12%
40%
as high as 20%

7

What is the benefit from screening?

reduction of death (1 year and long-term)
not see for women

8

What is the benefit of intervention on small aneurysms <4.0?
What about with EVAR?

no benefit surveillance vs sx
no survival benefit at 20 months

9

What is LAPLACE's law?

T=PR

10

What are some risk models used for estimating mortality with intervention on AAA? advantages/disadvantages?

glasgow aneurysm score
(open repair, good for elective or ruptured, poor external validity, performs poorly on high risk)

medicare model
(open or EVAR)

Vascular governance
north west model

all the scoring systems for EVAR have ROC <70

11

What are advantages/disadvantages of EVAR over open in regards to outcomes?

more likely to DC home
lower mortality peri-op

Evar constant rupture risk after repair
more likely to have subsequent interventions

12

When should beta-blockers be started before AAA surgery?

one month. no benefit if not started before

13

What % of EVAR convert to open ?What is the mortality associated to open conversion after EVAR?

1.5% mort 12%
2% mort 10%

14

What are advantages/disad of transperitoneal approach?

more rapid, greatest flexibility
widest access
evaluation of intra-abdominal pathology

longer ileus
greater fluid loss
difficult exposure junta or pararenal

15

What are advantages/disad of retroperitoneal approach?

avoids hostile abdo
good for junta/para
less physiologic stress/less ileum
good for obese
inflam AAA/horseshoe kidney
(lower LOS, cost and plum comps)

poor access to R renal and iliac
cannot eval intra-abdo pathology
more flank bulges/chronic wound pain

16

When do you consider preserving IMA?

signif SMA/celiac disease
bilat hypo occlusion
large IMA
prior colonic resection
sluggish back bleeding

17

What are renal or IV abnormalities encountered in AAA?

retro-aortic LRV
circ LRV
left-sided IVC
accersory renal verin
pre-aortic confluence of the iliac vein

18

What physiologic changes occur with aortic cross clamping?

10% increase in BP

if supracelia

preload increase if clamp prox to celiac as sphlanic cannot act as venous reservoir

increase after load and preload increase cardiac contractility and myocardial O2 demand

increase filling pressure

decrease EF

19

What are the consequences of unclamping?

reduction in PVR
reperfusion hyperemia
toxic metabolites, lactate, K, reactive O2 species, prostaglandins

20

What are the mechanism of renal injury in AAA repair

ischemia
emboli
renal vasoc even with infrarenal clamp

21

What are the rate of
reintervention for bleeding?
MI?
resp comps?
R insuff? dialysis?
colonic ischemia?

1.2%
10%
20%
10% 0.5% (increase if pararenal)
1-5% (on histo 30%)

22

What are RF for colonic ischemia?

ligation of IMA,
failure to revasc hypo,
extensive iliofem dz,
SMA stenosis,
embolism,
retractor injury,
previous colonic resection

23

How does colonic ischemia present?

diarrhea, melena
left colon almost always affected

24

What are finding of CI on flex sig?

early petechial hemmorhage interspersed with areas of pale oedematous mucosa

late segmental erythema, +/- ulcerations and bleeding
with severe mucosa cyanotic, dusky, grey or black

25

What is the rate of aorta-enteric fistula after AAA?
sexual dysfunction?
abdo wall hernias?
RP bulge?
SBO at 4 years?

1.6%
50%
30%
30-50%
25%

26

what are most common bacteria for infected AAA?

staph, salmonella, strep, E.Coli

27

What are signs of infected AAA on CT scan?

periaortic soft tissue mass, stranding of fluid, signs of destruction of the surrounding tissue
50% have contained rupture

28

What % of type II resolve with 6-12months?

80%
eurostar says no association with rupture

29

What is the yearly rupture rate for EVAR?

1% per year

30

Name some EVAR RCT and describe their results

EVAR-1, Dream, OVER
mortality higher for open then EVAR but no difference at 2 years. reintervention rate higher in EVAR

31

What are techniques to fix type I endoleak?

proximal extension
palmaz
snorkel
aorto-uni with fem fem
fenestrated

32

What factors affect migration?

increased angulation of neck, short neck,
neck thrombus,
large diameter,
neck dilation,
sac shrinkage


33

How often doe limb occlusion occur? what are risk factors?

5% 4 years
AI dz,
small distal aorta <14mm, tortuous iliacs

34

What are consequences of IA embolization?

pelvic ischemia
buttock claudication 50%, necrosis, colorectal ischemia 2%, erectile dysfunction 2%
paraplegia if bilat 3%

35

What is the rate of Type I endoleak with snorkel?

5% (50% require tx)
30d mort 4%

36

What are bladder pressure measurements for abdominal compartment syndrome?
When is a laparotomy indicated?

grade I 10-15mmHg
grade II 16-25mmHg
grade III 26-35mmHg
grade IV >35mmHg

grade III-IV

37

What are common venous anomalies encountered during open surgery for AAA?

retro-aortic renal 1-3%
circumaortic 0.5-1.5%
Left sided vena cava <1%
duplicated IVC 1-3%

38

What is the evidence for AAA screening?

RCT
>65, 40% reduction in AAA mortality
MA
44% in AAA mortality

39

What growth rate for AAA is concerning?

>1cm/year

40

How does family history effect rupture rate of AAA?

higher rupture rate if have a family hx of AAA

41

What cutoff for cardiopulmonary exercise testing predicts high risk after AAA?

10-15 ml/kg/min

42

What level of wall tension is high risk for AAA rupture?

>40N/cm
<30 is low risk

43

What non-IFU related scenarios favour open >EVAR?
EVAR>opan

horsehoe kidney with multiple arteries
require IMA latency

redo
abdo stoma
wall defects
poor pulmonary

44

What are renal abnormalities that can be encountered during AAA repair?

horseshoe
pancake
crossed-fused renal ectopia

all of these usualy have multiple RA

45

What adjuncts can be used to protect kidneys during AAA?

cold hyperosmolar crystalloid
HTK solution
saline with mannitol

cooling kidney by 30% reduces metabolic demands by half

46

List collateral pathways that supply colon.

marginal artery
meandering artery
GDA
middle sacral
hypo (lateral sacral, middle rectal, superior rectal, obturator)

47

What is repair threshold for iliac aneurysm?

3-3.5cm

48

Which graft does not have suprarenal fixation?

Gore, aorfix

49

What were results of EVAR-1?

RCT open vs EVAR
30d mort 1.7 vs 4.7 (E vs O)
secondary more common in EVAR
no diff at 6 years

50

What were the results of the DREAM trial?

RCT
peri-op mort
1.2 vs 4.6 in EVAR vs OPEN
combined MACE and mort favoured EVAR
no diff at 6 years

51

What were the results of the OVER trial?

peri-op mort 0.5 vs 3% E vsO
no diff at 2 years

52

From eurostar data which graft had
highest migration/endoleak
highest rate of limb occlusion

aneurs, talent
zenith

53

What is the rate of ED in EVAR?

20% for unilateral embolization

54

What are mortality rates for rAAA?

2/3 before hospital
50% with open
30% with EVAR

55

What are some management considerations for rAAA?

permissive hypotension
avoid hypothermia
cell saver
blood in room

56

What are outcomes for rAAA?
bleeding
colinic ischemia

10%
40% open, 20% EVAR

57

What features indicate high peri-op mortality for rAAA?

cardiac arrest
liver failure
MOF

58

What are SVS guidelines for pre-op workup for AAA?

EKG
NIST if 3 or > RF for CAD

59

Ideally how long to wait after PCI?

4-6 weeks for BMS
12months for DES

60

What are screening recommendations for AAA?

One-time screening for
men >65 yo
55 yo if fam hx of AAA
women >65 with fam hx of aaa or who have smoked

Re-screening not recommended if >65yo and aortic diameter <2.6cm

61

When do increase surveillance to q6months?

>4.5cm

62

What are signs and symptoms of aortocaval fistula?

machinery murmur
high output failure
limb edema
hematuria