2. Mesentric ischemia usually result of a sudden and
usually temporary reduction in blood flow
insufficient to meet metabolic demands of discrete
regions of the bowel
■ 0.1 % of hospital admissions
■ 1%-2% of admissions for abdominal pain
■ Incidence – 9 in 100,000 person – years
■ Incidence increases with age
■ More common in women
■ Mortality – 24% to 96% with average of 69%
3. Mesenteric vasculature
Comprises of 3 major aortic branches
with collaterals
■ Celiac axis
■ Superior mesenteric artery
■ Inferior mesenteric artery
4. Celiac axis – foregut (distal esophagus to
duodenum, hepatobiliary, spleen)
■ Left gastric artery
■ Splenic artery
■ Common hepatic artery
Superior mesenteric artery – midgut ( Jejunum to
mid colon )
■ Inferior pancreaticoduodenal artery
■ Jejunal branches
■ Ileal branches
■ Middle colic artery
■ Right colic artery
■ Ileocolic artery
Inferior mesenteric artery – hindgut ( mid colon
to rectum )
■ Left colic artery
■ Sigmoid arteries
■ Superior rectal artery
5. Collateral flow:
■ Marginal artery of
Drummond – collateral
connection between SMA
and IMA along the
mesenteric border
■ IMA and internal iliac –
supply good collaterals to
the rectum
7. Venous Drainage of Gastrointestinal
Tract
■ Veins of portal venous
system
■ Systemic veins
■ Blood from GIT enter the
liver via portal vein and
leave the liver via hepatic
veins to enter the inferior
vena cava
8. Portal system
It is formed by the union of
the splenic vein and the
superior mesenteric vein
posterior to the neck of the
pancreas at the level of
vertebra L2.
11. Acute mesenteric ischemia
■ Acute mesenteric ischemia (AMI) may
be defined as an abrupt reduction in
blood flow to the intestinal circulation
of sufficient magnitude to
compromise the metabolic
requirements and potentially threaten
the viability of the affected bowel
■ Embolic couses (50%)
– Arrhythmia
– Valvular disease
– Myocardial infarction
– Hypokinetic ventricular wall
– Cardiac aneurysm
– Aortic atherosclerotic disease
– Iatrogenic
■ Thrombosis (25%)
– Atherosclerotic disease
■ Nonocclusive (5% to 15%)
– Pancreatitis
– Heart failure
– Sepsis
– Cardiac bypass
– Burns
– Renal failure
– Medications
12. Mechanism of Injury
■ Hypoxia causes detectable injury to superficial mucosa
within one hour
■ Prolonged severe ischemia – necrosis of villous layer
– Leads to transmural infarction in 8 to 16 hrs
■ Reperfusion injury – mediated by release of oxygen free
radicals and neutrophil activation
13. Presenting of symptoms
■ 95% with abdominal pain
■ 44% with nausea
■ 35% with vomiting
■ 35% with diarrhea
■ 16% presented with blood per rectum
15. Clinical Manifestations
■ Thrombotic/embolic mesenteric occlusion present
with sudden-onset severe mid-abdominal pain that
is out of proportion to the physical findings
– typically have a history of chronic postprandial
abdominal pain and significant weight loss.
■ NOMI pain usually not as sudden as that noted with
embolic or thrombotic occlusion: it is generally
more diffuse and tends to wax and wane
– unlike the pain associated with occlusive disease,
which tends to get progressively worse
17. Lap workup
■ Metabolic acidosis
■ Hyperamylasemia
■ Elevation of lactate dehydrogenase, aspartate
aminotransferase, and creatine phosphokinase.
■ Hyperkalemia and hyperphosphatemia are present - Bowel
infarction
■ ECG - cardiac rhythm.
18. Plain x-ray
■ Supine / erect
■ Chest – AP view
Suspicious findings
– Non specific ileus
– Dilated bowel loops
– Thumb printing
– Separation of bowel loops
– Intramural gas
– Free air
Majority of the cases plain films are non diagnostic
21. CT scan
■ Sensitivity - 64%
■ Specificity - 92%
■ CT is the diagnostic technique of choice for acute MVT
– sensitivity exceeding 90%.
■ 3D recon of the aorta and its branches show additional detail
– sensitivity and specificity to 94% to 96%
■ The limitations and risks of CT angiography
– renal insufficiency or contrast allergies
– limitations of contrast volume, and metal artefacts obscuring
the area of interest
22. CT scan
• Indirect findings of arterial bowel ischemia and may show the
arterial occlusion or mesenteric venous thrombus.
• Dilation of the bowel lumen,
• Bowel wall thickening
• Abnormal bowel wall enhancement,
• Arterial occlusion,
• Venous thrombosis
• Intramural or portal venous gas
• Lack of bowel inhancment
23. CT scan
■ Symmetrical bowel wall thickening greater than 3 mm in a
distended segment of bowel suggests ischemia
■ Greater degrees of bowel wall thickening should raise suspicion
of mesenteric venous thrombosis (MVT).
24. CT scan
Pathologic Damage CT Findings
Vasoconstriction Wall hyper density
Absence of wall enhancement
Increased capillary permeability Wall thickening
Bowel dilation
Mucosal cellular necrosis Pneumatosis
Gas in mesenteric vein branches
Gas in portal vein branches
Transmural bowel necrosis Pneumoperitoneum
Retropneumoperitoneum
Ascites
25. CT scan shows inflammatory changes and thickening
of the hepatic flexure
27. Superior mesenteric artery embolism.
CT shows that mural enhancement is absent at most intestinal loops.
28. CT images abdomen show gas in portal venous branches (A), gas in
mesenteric veins (circle, B), and gas in bowel wall (arrowheads, C).
29. Arteriography
■ Definitive diagnosis - acute and chronic mesenteric ischemia.
■ Arteriograms
– Establish the diagnosis
– Assist in differentiating between acute embolic, thrombotic,
or nonocclusive mesenteric ischemia
– Allow proper planning of the revascularization procedure.
– AP and lateral views of the aorta and the mesenteric
branches are required for proper arteriographic evaluation.
– The lateral view is particularly important to examine the
proximal celiac artery and SMA, which overlap the aortic
contrast column on AP views.
30. Arteriography
■ Acute embolic occlusion of the SMA is abrupt occlusion of the
artery, usually at a branch point where the vessel tends to
narrow
■ If imaged acutely, a meniscus sign (crescent) is often observed.
■ If secondary thrombosis occurs proximal to the embolus, the
classic meniscus sign of embolic occlusion will be obscured.
31.
32.
33. Management
■ Effective management
– Early diagnosis
– Aggressive resuscitation
– Early revascularization
– On going supportive care
■ Medical treatment (correction electrolyte, systemic
heparin , antibiotic )
■ Endovascular Treatment
■ Surgical treatment
34. Endovascular therapy
■ Thromboltic therapy , angioplasty and stenting
■ Indication :
– Early presentation
– Angiography finding of good collateral circulation
– No bowel infraction
If symptom not improved within 4 hours or peritonitis
developed stop thrombolytic and prepare pt for surgery
35. Complication
■ Risk of ingoing ischemia damage during the therapy
■ Risk of significant gastrointestinal hemorrhage
■ The integrity if bowel can not be asses
44. Bypass surgery
For pt with thrombosis of proximal SMA due to atherosclerotic occlusive diseas
Type of bypass :
Antegrade : using supraceliac aorta mostly with synthetic graft and is the best option
for CMI
its pitfall :
– the acuity of situation
– difficult exposure.
– clamping may case further hypoperfusion to the bowel and kidney
It indicated when infra renal aorta is severely diseased .
Retrograde :
Using infrarenal aorta or iliac artry for the origin
47. Second look Laparotomy
■ Usually within 24 hours
■ Decision to reoperate made at first operation, independent
of early postoperative course
■ “third-look” procedures may be necessary to check
anastomoses or precarious segments
48. Management of non-occlusive
mesenteric ischemia
■ Correct underlying condition.
■ Correct underlying condition.
■ Optimize fluid status,
■ improve cardiac output, and eliminate vasopressors.
■ Consider catheter-directed intraarterial infusion of vasodilator (papaverine)
Laparotomy if peritoneal signs develop Laparotomy if peritoneal signs develop
49. Chronic mesenteric ischemia
■ Presented with intestinal angina associated with need
for increased blood flow to the intestine .
■ abdominal cramping and pain following ingestion of
meal .
■ weight loss and chronic diarrhea
Abdominal pain without weight loss is not chronic mesenteric angina
physical examination :
– Abdominal bruit
– Manifestation of atherosclerosis
50. Duplex US findings in isolated stenosis of
the CA. (a) Lateral US image obtained in
color mode shows color aliasing. (b) Lateral
US image obtained in Doppler mode shows
signs of moderate stenosis with increases in
systolic and diastolic velocities, as well as
mild turbulence. (c) Lateral US image
obtained in Doppler mode shows major
poststenotic turbulence and Doppler
aliasing, which indicate a stenosis of greater
than 75%.
51. Colonoscopy
■ no evidence of peritonitis or perforation
■ Preferred to contrast enemas, more sensitive in detecting
mucosal lesions
■ Segmental distribution, abrupt transition between injured and
non injured mucosa, rectal sparing, and rapid resolution on
serial endoscopy
■ “single-stripe sign” – linear ulcer along longitudinal axis
■ Biopsies may show non-specific changes (mimicking Crohn’s
disease)
52. ■
Endoscopy of ischemic colitis may reveal continuous necrosis
and mucosal friability that resembles ulcerative colitis (left
panel); discrete ulcers with surrounding edema may also be
seen (right panel). Courtesy of James B McGee, MD.
53. Contrast studies
– Thumbprinting most suggestive on double contrast study seen
early in disease
– In a small series of patients with mucosal ischemia 75%
+thumbprinting, 60% longitudinal ulcers (source)
54. Diagnosis
■ Mesenteric angiography :
is the gold standerd for conformation of chronic
mesenteric ischemia arterial occlusion .
■ magnetic resonace angiography:
Is an alternative if contrast dye is contraindication
55. Three-dimensional computed tomography angiography shows an extremely severe
superior mesenteric artery stenosis (small white arrow), an occluded celiac trunk
(large white arrow), and an enlarged and patent inferior mesenteric artery (black
arrow) in a patient with symptoms of intestinal angina. The initial imaging evaluation
of suspected chronic mesenteric ischemia should involve a noninvasive modality
56.
57. Mangment
■ Cardia evaluation
■ Medical mangment of athrosclrosis :
– Lipid lower medication
– Exercise
– Cessation of smoking
■ Endovascular procedures :
– For selected patient
58. Mesenteric Vain Thrombosis
■ 20% Idiopathic
■ Hypercoagulable States
■ Low-flow (CHF, Cirrhosis with PH,
Budd-Chiari)
■ Intra-abdominal inflammatory or
suppurative processes and
malignancies
■ Smoking, prior DVT or thrombosis
60. Treatment
• Systemic Anticoagulation
• Exploration with resection of non-viable bowel for
peritonitis; multiple look
• Poorly defined role for thrombectomy and
operative thrombolysis
• Poor Outcomes
61. Median arcuate ligament syndrome
■ Aka- Celiac Artery
Compression Syndrome
• Etiology - Compression of
CA by the median arcuate
ligament.
• Female 20-40 years old
• Symptom - post-prandial
epigastric abdominal pain
• Treatment - release the
median arcuate ligament
