Module 2: Mesenteric Vasculature Flashcards

(39 cards)

1
Q

what does splanchnic artery refers to

A
  • vessels that supply the bowel with blood.
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2
Q

what three arteries are included in splanchnic arteries

A
  • celiac artery
  • superior mesenteric artery
  • inferiori mesenteric artery
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3
Q

what is the first branch of the aorta and what are its branches

A
  • celiac axis

- divides into left gastric, splenic, and common hepatic arteries

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4
Q

what 5 organs are supplied by the celiac artery

A
  • stomach
  • liver
  • pancreas
  • duodenum
  • spleen
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5
Q

what is the doppler characteristics of the celiac artery

A
  • low resistance waveform
  • PSV 50-160cm/sec
  • EDV = 55 cm/s
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6
Q

where is the origin of the SMA

A
  • 1-2cm distal to the origin of the CA
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7
Q

what 4 organs are supplied by the SMA

A
  • small intestine
  • cecum
  • ascending colon
  • part of transverse colon
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8
Q

what is flow in the SMA dependant on

A
  • metabolic activity of the bowel
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9
Q

what is the doppler flow of the SMA in the fasting state

A
  • high resistance
  • occasional reverse component
  • PSV 110-177cm/s
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10
Q

where is the origin of the IMA

A
  • originates from the distal aorta 3-4cm above bifurcation heading to the left
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11
Q

what are the 5 structures fed by the IMA

A
  • left hand of the transverse colon
  • descending colon
  • iliac colon
  • sigmoid colon
  • part of rectum
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12
Q

is the IMA easy or hard to see and if its easy to see what does that mean

A
  • should be hard to see

- if easy to see may suggest SMA occlusion

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13
Q

doppler flow of the IMA

A
  • similar to SMA
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14
Q

what are the 2 major collateral pathways in mesenteric vasculature

A
  • pancreaticoduodenal arcade

- arc of riolan and marginal artery of Drummond

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15
Q

what is the pancreaticoduodenal arcade

A
  • links the celiac and SMA vie arterial branches that surround the duodenum and pancreas
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16
Q

what is the arc of riolan and marginal artery of Drummond

A
  • link the IMA and SMA via arterial branches

- the left colic-middle artery is common branch for collateralization in this group

17
Q

is splanchnic artery occlusion often symptomatic or asymptomatic

A
  • asymptomatic

- due to potential for collateralization

18
Q

what are the 3 mechanisms of disease in the mesenteric vessels

A
  • stenosis/occlusion
  • acute mesenteric ischemia
  • chronic mesenteric ischemia
19
Q

what condition can stenosis/occlusion cause

A
  • acute or chronic bowel ischemia
20
Q

what can prevent acute or bowel ischemia when a stenosis/occlusion is present

A
  • collateralization
21
Q

what vessel is important to interrogate before looking at the mesenteric vessel when stenosis is suspected

A
  • aorta

- any narrowing or aneurysmal disease in the aorta may encroach on the origins of the celiac and mesenteric vessels

22
Q

what exam is the gold standard for diagnosing stenosis

A
  • arteriography
23
Q

what reduction in vessel diameter is considered to be clinically significant

24
Q

what PSV in the celiac and the SMA considered a clinically significant stenosis

A
  • CA PSV >/= 200cm/s

- SMA >/= 275cm/s

25
what PSV ratio between the artery and aorta will indicate > 70% stenosis
>3.5
26
when is occlusion of the CA indirectly considered as a diagnosis
- reversal of flow is seen in the gastroduodenal or common hepatic arteries
27
what other condition can cause stenosis type symptoms in the celiac artery other than atherosclerosis
- compression o the celiac axis by the median arcuate ligament of the diaphragm
28
how does the median arcuate ligament compression of the celiac axis mimic a stenosis and who is commonly effected
- ligament lies superior to CA origin and affects flow with respiration - deep inspiration there is no obstruction and on expiration and quiet respiration the stenotic appearance returns - younger patients
29
what is acute mesenteric ischemia
- sudden onset of abdominal symptoms - due to an embolic process that progresses to a life threatening condition - surgical emergency - CT/angio is preferred method of diagnosis
30
what is chronic mesenteric ischemia
- postprandial pain that leads to the patient changing their dietary content and habits
31
what is the best method of diagnosis for chronic mesenteric ischemia
- angiography
32
what must occur for chronic mesenteric ischemia to happen
- at least 2 major arteries to the bowel to be involved with atherosclerosis
33
in the sonographic assessment of chronic mesenteric ischemia is the celiac axis commonly scanned and why
- celiac axis is not affected post prandially therefore it is not usually scanned
34
protocol for sonographic assessment of chronic mesenteric ischemia
- patient scanned pre and post prandially - in fasting state flow should be high resistance - 20-30 minutes after patient given calories the study is repeated, done sooner if patient is symptomatic - studies are then compared
35
what is the normal result of an assessment for chronic mesenteric ischemia
- post prandial PSV and EDV increase | - EDV almost doubles
36
what is the abnormal result of an assessment for chronic mesenteric ischemia
- low resistance pattern with high velocities seen in fasting state is positive, then no need to test post prandial - post prandial SMA and IMA remain high
37
what is evaluating the flow changes in the bowel similar to
- exercise stress test
38
why is the evaluation of bowel ischemia difficult to diagnose with ultrasound
- bowel ischemia is not always due to disease in the main celiac and mesenteric arteries
39
what are 4 other causes of ischemia in the bowel
- hypotension - small vessel disease - emboli - venous obstruction