Chap 151-154 Mesenteric Flashcards
In embryology, what gives rise to the abdo aorta?
primitive dorsal artery
In embryology, what gives rise to the celiac?
10th segmental branch
In embryology, what gives rise to the SMA?
11th segmental branch
In embryology, what gives rise to the IMA?
21st segmental branch
What are the branches of the celiac?
left gastric
splenic
common hepatic
What is the most frequent anatomic variation of the celiac?
hepatic arises from SMA or directly from aorta
What are the branches of the SMA?
PDA middle colic right colic ilieocolic third order branches
What are the branches of the IMA?
sigmoidal branches left colic (becomes marginal artery)
What are SMA and IMA connections?
marginal artery
meandering artery
sigmoidal branches lead to L and R rectal arteries which collateralize with branches of hypogastric
What are SMA and IMA connections?
marginal artery meandering artery (l colic to middle colic)
How does percentage of blood flow in the bowels change with eating?
10% of CO with shock
25% at rest
35% after large meal
What do waveforms of the SMA look like during fasting and postprandial?
high arterial resistance with low diastolic flow
low-resistnace throughout both systole and diastole
What is NOMI?
Impaired intestinal perfusion in absence of thromboembolic occlusion
10% of mesenteric ischemia
What causes NOMI?
vasospams in arteries that supply mucosal and submucosal layers in SMA distribution
What are angiogrpahic findings for NOMI?
Narrowing of the origins of multiple branches of SMA Alternate dilation and narrowing of intestinal branches (string of sausages)
Spasm of mesenteric arcades
Impaired filling of the intramural vessels.
What are RF for NOMI?
low flow states hypovolemia systemic vasoconstrictirs AI CPB reperfusion injury
What is treatment for NOMI?
IA infusion of vasodilator (mort 50%)
Papverine at 30-60mg/hr
Papaverine metabolized by the liver so hypotension rarely a problem
What are celiac-sma collaterals?
GDA-PDA
What are IMA-internal collaterals?
hemorrhoidals to internal iliac
What are causes of visceral vessel disease?
Atherosclerosis most common Fibromuscular disease Dissection, neurofibromatosis Rheumatoid arthritis Takayasu arteritis Giant cell arteritis Polarteritis nodosa Radiation injury Systemic lupus Buegers disease Drugs like cocaine Median arcuate ligament syndrome
What is natural history of visceral vessel stenosis?
1/3 devel mesenteric schema within 3 years
largely asympto until at least two vessels with critical stenosis
What is clinical presentation for CMI?
Food aversion
Postprandial pain 30 mins after a meal persisting for 5-6hours
Midabdo in location and crampy or dull
WL
What velocities on duplex suggest stenosis?
> 70%
ESV SMA >275
ESV celiac >200
> 50%
SMA EDV>45
celiac EDV >55 or reversal hepatic flow
What are other diagnostic test?
CTA/MRA
gastric tonometry
What are positive result of gastric tonometry for CMI?
Reduced CO2 washout from ischemic tissue cause PCO2 to rise
What are positive result of gastric tonometry for CMI?
Reduced CO2 washout from ischemic tissue cause PCO2 to rise
What are indication for revasc for CMI?
symptoms
some suggest 3 VD
during aortic reconstruction
What is advantages of endovascular?
likley shorter hospital stays, reduced M&M
probably less long-term patency
What are open bypass strategies?
supracelia (tunnel retropancreatic, ant to L renal
retrograde from infrarenal aorta or CIA (right lays better)
What are the results of open vs endo symptom relief? survival? M&M? restenosis rate?
same 90% for both
60% 5 year survival
endo lower M&M
endo higher restenosis
What are open bypass strategies?
supracelia (tunnel retropancreatic, ant to L renal
retrograde from infrarenal aorta or CIA (right lays better)
What is median arcuate ligament syndrome?
Fibrous edge of diaphragmatic crura croseses ant to aorta and above celiac and compresses celiac
What is treatment for MALS?
division of crura with endo possibly
What are features of embolism in acute mesenteric ischemia?
50% of cases
50% lodge distal to middle colic
25% are thrombosis on top of chronic disease
What are features of AMI on X-ray?
Thumbprinting in advanced cases of ischemia (pneumatosis)
What are features of AMI on CT?
Pneumatosis Vessel occlusion Hepatic venous air Lack of bowel wall enhancement Free ait Solid organ infarct Mucosal enhacement Ascites
What are techniques to examine the bowel intra-operatively?
visible/palpable pulsation in arcade doopler signals in the arcade color and appearance of the bowel serosa peristalsis bleeding from cut surfaces fluorescein perfusion fluorometer laser Doppler flowmeter
What are causes of mesenteric vein thrombosis?
idopathic (primary) trauma inflam state (pancreatitis) peritonitis portal htn obesity hypersplenism thrombophilia
What does bowel look like on inspection?
limited segment of intestinal schema with edema and reddish discolouration
small bowel and mesentery
What does bowel look like on inspection?
limited segment of intestinal schema with edema and reddish discolouration
small bowel and mesentery
What are treatment options?
if no peritonitis then AC with heparin
if peritonitis or bleeding, the ex lap, bowel resection
What is in hospital mortality for MVT?
20%
What are other therapeutic options for MVT?
TIPS
perc transhepatic tpa
thrombolysis via SMA
