Chapter 133 - Acute mesenteric ischemia

Question 1

Epidemiology of acute mesenteric ischemia

Answer 1

1) age 60-70’s 2) history cardiac arrhythmia, MI, CHF, arterial emboli 3) history of chronic mesenteric ischemia

Question 2

Causes of acute mesesnteric ischemia

Answer 2

1) embolism 40-50% 2) thrombosis 25-30% 3) NOMI 20%

Question 3

Most common lodged location of cardioemboli in the SMA

Answer 3

1) distal to middle colic 50% 2) SMA origin 15%

Question 4

Most common lodged location of atheroemboli

Answer 4

more distal and thus more bowel sparing

Question 5

Rate of chronic mesenteric ischemia in the history of patients with acute mesenteric ischemia

Answer 5

20%

Question 6

NOMI key points

Answer 6

1) mesenteric vasospasm 2) highest mortality rate due to associated multisystem organ failure 3) hypothesis of intestinal vasospasm to maintain cardiac/cerebral perfusion 4) other hypothesis of reperfusion injury more important than ischemia alone

Question 7

Amount of maximal blood flow needed to maintain mesenteric health

Answer 7

20%

Question 8

Mortality of AMI if diagnosis is made within 24 or more than 24 hr

Answer 8

50% if made in first 24hr 30% if made after

Question 9

Diagnostic lab tool in AMI

Answer 9

D-dimer: if normal rule out Urinary levels of Ileal bile acid binding protein (I-BABP), intestinal FABP and liver FABP

Question 10

X-RAY sign of AMI

Answer 10

75% will show abnormality 1) ileus 2) bowel edema thumbprinting 3) pneumatosis 4) free air

Question 11

Duplex in AMI

Answer 11

no role 1) bowel gas 2) abd pain 3) missing distal emboli 4) lack availability

Question 12

CTA finding of AMI

Answer 12

TABLE 133.1

Question 13

Initial resuscitation of AMI

Answer 13

1) fluid then blood 2) correct lytes 3) antibiotics 4) avoid pressors if possible especially pure alpha agonists

Question 14

Mortality rate of NOMI

Answer 14

40-50%

Question 15

Angiographic criteria for NOMI

Answer 15

1) narrowing of origin of multiple branches of SMA 2) alternate dilation and narrowing of intestinal branches (string of sausages) 3) spasm of mesenteric arcade 4) impaired filling of intramural vessels

Question 16

Treatment of NOMI

Answer 16

Direct intra-arterial vasodilator infusion for days Papaverine (phosphodiesterase inhibitor) at 30-60 mg/hr

Question 17

Papaverine metabolized by

Answer 17

liver

Question 18

What is not compatible with papaverine

Answer 18

heparin sodium chemically incompatible

Question 19

Exposure of the SMA

Answer 19

Anteriorly 1) base of transverse mesocolon without mobilizing duodenum 2) for embolectomy without need for retrograde bypass 3) fogarty 2-3 or milking mesentery 4) proximal dissection care for pancreas and splenic vein Laterally 1) free up ligament of Treitz 2) mobilize 4th duodenum 3) just inferior to pancreas 4) for bypass use lazy C from right common iliac

Question 20

Different SMA bypass option

Answer 20

1) antegrade: supraceliac aorta disease free but hemodyanmically already unstable 2) retrograde from aorta: can kink 3) lazy C from iliac

Question 21

Patency difference between prosthetic and vein for SMA bypass

Answer 21

Anecdotally prosthetic better but no clear evidence less kinking but cannot use in soilage FV can be better but again no clear evidance longer dissection

Question 22

Results of retrograde open mesenteric stenting mortality

Answer 22

17% mortality in hospital

Question 23

Epidemiology of spontaneous visceral dissection

Answer 23

1) age 54 years 2) 4x in men 3) 50% with aneurysmal degeneration 4) anticoag alone success in 65%

Question 24

Treatment algorithm for spontaneous visceral dissection

Answer 24

Symptomatic = primary stenting –> anticoagulation if fail –> open surgery if fail

Question 25

Indication to treat spontaneous visceral dissection

Answer 25

1) aneurysm > 2cm 2) concern for bowel ischemia 3) stenosis > 80% 4) abdominal pain non-resolving or recurrent

Question 26

Intraoperative vasodilators

Answer 26

1) papaverine 2) glucagon