Mesenteric Vasculature Flashcards
Splanchnic arteries supply what area?
The bowel
What does the splanchnic arteries separate into? 3
- Celiac
- Superior mesenteric artery
- Inferior mesenteric artery
Where is the splanchnic artery located in relation to the aorta?
Anterior wall
What is the first branch off the aorta?
Celiac
What dies the celiac divides into? 3
- The left gastric
- Splenic
- COmmon hepatic arteries
What does the celiac artery supply? 5
- Stomach
- Liver
- Pancreas
- Duodenum
- Spleen
What is the Doppler signal of celiac artery? 2
Low resistance
1. PSV 50-160 cm/sec
2. EDV < 55cm/s
Waveform more important then numbers
Where is the SMA located?
1 to 2 cm distal to the celiac artery
The SMA and celiac occasional share what?
Common trunk
What does the SMA supply? 4
- Small intestine
- Caecum
- Ascending colon
- Part of the transverse colon
SMA flow varies with what?
Metabolic activity of the gut
What is the Fasting SMA waveform like? 2
- Higher resistance with occasional reverse component (multiphasic)
- PSV varies between 110-177cm/s
waveform more important than numbers
What does the SMA look like post prandially?
Low resistance with increased velocities
Where is the IMA located? 2
- Distal aorta
- 3-4 cm superior to the bifurcation
What does the IMA supply? 4
- Left half of transverse colon
- Descending iliac
- Sigmoid colon
- Part of the rectum
How easy is it to image the IMA?
Difficult to image, but easy visualization of the IMA may suggest SMA occlusion
What does the pancreaticoduodenal arcade link?
Links celiac and SMA via arterial branches that surround the duodenum and pancreas
What does the arc of rimland and marginal artery of Drummond link? 2
- The IMA and SMA via mesenteric arterial branches
- Left colic- middle artery is common branch for collateralization in this group
In terms of the arc of Roland, because of the potential for collateralization, the splanchnic arterial occlusion is often asymptomatic or symptomatic?
Asymptomatic
What are indications for duplex testing? 3
- Suspected chronic ischemia (CMI)
- Median arcuate ligament syndrome (MALS)
- Undergone prior mesenteric intervention - stents bypass grafts
What does stenosis/ occlusion cause?
Acute or chronic bowel ischemia, but often prevented with collateralization.
What do we assess in we suspect stenosis?
Assess the aorta documenting any narrowing or aneurysmal disease that may encroach on the origins of the celiac and mesenteric vessels prior to assessing them
What is the gold standard for diagnosing stenoses?
Arteriography
What does doppler look like in a fasting state? 4
- Stenosis causing >70% diameter reduction
- Celiac artery - PSV of >200cm/s
- SMA- PSV >275 cm/s
- IMA- no PSV parameters
In terms of doppler of stenosis, what is the ratio of the artery PSV over PSV?
PSV > 3.5 indicates a stenosis >70%
Occlusion of the CA may indirectly be considered when what happens?
Reversal of flow is seen in the gastroduodenal or common hepatic arteries
Who/What might we see with post-prandial pain with chronic mesenteric ischemia? 3
- Weight loss
- Smoking history
- Women 40-70 most common
What do we see with acute mesenteric ischemia?
Sudden onset of abdominal symptoms, usually progresses to life threatening conditions due to bowel necrosis
What is acute mesenteric ischemia caused by?
Embolus to the mesenteric arteries or thrombosis of an arter with existing chronic disease
IS acute mesenteric ischemia emergency?
Yes surgical
What is the preferred method of diagnosis for acute mesenteric ischemia?
CT/Angiography
What is the most common demographic affected by Median arcuate ligament syndrome? 4
- Younger
- <40
- Females
- History months to years of upper abdominal pain, not necessarily smokers, almost always thin
What is MALS?
Transient compression of the celiac artery origin by the median arcuate ligament of the diaphragm during exhalation, which is relieved or decreased during exhalation
What is treatment for MALS?
Laparoscopic release of the median arcuate ligament
What does MALS look like with U/S? 2
- Celiac artery PSV increases during exhalation and decrease during inhalation
- 2D of proximal celiac artery typically demonstrates a characteristic “hooked” apeparrence
In terms of the CMI, what is the waveform in a fasting state normally?
Normally in a fasting state the waveform is high resistance
In terms of CMI, patents are scanned when?
Pre and post prandially
20-30 minutes after the patient is scanned for CMI, what happens? 2
- The patient has been given a high caloric liquid mean, the study is repeated, or sooner if the patient becomes asymptomatic
- Hemodynamics responses are than compared from both states
In terms of CMI, what would result in not doing another test? What re post prandial velocities of the SMA and IMA?
- Low resistance, high PSV in a fasting patient is a positive finding and no need to test post prandially
- Post prandial velocities in the SMA and IMA remain very high
In terms of CMI, evaluating flow changes pre and post prandially is what type of test?
Exercise stress test
In terms of CMI, evaluation of bowel ischemia with sonography is made more difficult as what?
Bowel ischemia is not always due to disease in the main celiac and mesenteric arteries
In terms of CMI, Ischemia may be due to what? 4
Other causes such as
1. Hypotension
2. Small vessel disease
3. Emboli
4. Venous obstruction
When would we feel pain in terms of chronic mesenteric ischemia?
Post prandial
What do we need to use to see chronic mesenteric ischemia?
Angiography
In terms of Chronic mesenteric ischemia, how many arteries must be involved with atherosclerosis?
2-3
Why is it challenging to diagnose chronic mesenteric ischemia?
The extensive amount of collaterals that may develop
