Chapter 49 - Aortoenteric fistula

Question 1

First primary AEF described

Answer 1

1829 Sir Astley Cooper

Question 2

First secondary AEF

Answer 2

1953 Brock

fistula between proximal anast and duodenum

Question 3

First repair of primary AEF

Answer 3

1954 Zenker

Question 4

First repair of secondary AEF

Answer 4

1958 MacKenzie

Question 5

Incidence of AEF

Answer 5

0. 04-0.07% general population

0. 69-2.35% with AAA

Question 6

Causes of primary AEF

Answer 6

1) foreign body
2) tumor
3) radiotherapy
4) infection (TB, syphilis, klebsiella, salmonella)
5) GI disease (PUD, biliary stone)

Question 7

Epidemiology of primary AEF

Answer 7

diameter 6.2 cm
age 64
male to female 3:1

Question 8

Most common GI location of primary AEF

Answer 8

3rd and 4th duodenum 54%

due to tether of ligament of Treitz

Question 9

Other primary AEF locations

Answer 9

esophagus 28%
small/large bowel 15%
stomach 2%

Question 10

Duodenal and aortic factors that lead to AEF

Answer 10

Duodenum: ulcer, cancer, diverticulitis, foreign body
Aorta: pulsatile pressure, rupture, mycotic, aortitis

Question 11

Incidence of secondary AEF

Answer 11

0.36-1.6% after open AAA

Question 12

Onset of secondary AEF after AAA

Answer 12

2-6 years

Question 13

Graft enteric erosion definition

Answer 13

fistula not at the anastomosis but rather through the graft interstices

Question 14

Rate of secondary AEF after EVAR

Answer 14

0.46%

Question 15

Triad of PRIMARY AEF

and other associated lab findings

Answer 15

1) GI bleed 64-94%
2) abdominal pain 32-48%
3) pulsatile mass 17-25%

all 3 symptoms = 11%

HGB < 80 = 67%
WBC > 10 = 25%

Question 16

Symptoms of secondary AEF

Answer 16

1) hemorrhage 73%
2) sepsis 41%
3) abd pain/back pain 22%
4) graft limb thrombosis 14%
5) groin fistula 11%
6) peripheral abscess 8%
7) femoral pseudoaneurysm 5%
8) peritonitis 5%

Question 17

Herald bleed

Answer 17

minor bleed self limiting due to vasospasm and thrombus formation

Question 18

CT findings of aef

Answer 18

1) effacement of fat planes
2) perigraft fluid
3) soft tissue thickening
4) ectopic gas
5) tethering of adjacent thickened bowel loops
6) extravasation of contrast into involved bowel segment

Question 19

detection rate of CT and EGD and angio for AEF

Answer 19

CT = 61%
EGD = 25%
Angiography = 26%

Question 20

problem with angiography for detecting AEF

Answer 20

likely thrombus occluding fistula and therefore may not identify

Question 21

Chance of second bleeding after herald bleed in first 6 hours and 24 hours

Answer 21

30% 6 hours

50% 24 hours

Question 22

Seeding in extraanatomic bypass graft

Answer 22

15-25%

Question 23

Results with EVAR treatment of AEF

Answer 23

1) mortality 29%

2) persistent infection/hemorrhage 44%

Question 24

Natural history untreated secondary AEF

Answer 24

mortality 13-86%
amputation 10%
3 year survival 50%