Mesenteric Ischemia

Question 1

What puts a patient at risk for mesenteric ischemia?

Answer 1

Obtain an ECG to see if the patient has atrial fibrillation which can put them at risk for an embolic cause of mesenteric ischemia.

Question 2

What is the classic presentation of a mesenteric ischemia?

Answer 2

• Over 50 years of age, sudden onset abdominal pain, possible nausea, vomiting, and diarrhea.
• Abdominal pain Initially severe and diffuse without any localization.
• Abdominal pain out of proportion to examination (soft, no guarding or rebound).
• Late findings: BOWEL INFARCTS: Abdominal distension with guarding, rebound, and absence of bowel sounds. They may develop abdominal wall rigidity. Bloody diarrhea and heme-positive stools are a late finding after bowel has infarcted.

Question 3

What are the four different etiologies of mesenteric ischemia?

Answer 3

mesentery artery embolus, mesentery artery thrombosis, mesenteric vein thrombosis, and non-occlusive ischemia.

Question 4

Mesentery artery embolus

Answer 4

MCC of mesenteric ischemia (50%)
Poor prognosis, 70% mortality rate
Sudden onset and classical pain out of proportion
Risk factors: a fib, post MI, valvular heart disease
Usually involves SMA

Question 5

Mesenteric vein thrombosis

Answer 5

Least Common cause
Usually superior mesenteric vein
Can occur acutely or over long periods of time
Pain may be more diffuse and less severe
No post prandial pain
Risk factors: hypercoagulable states (Factor V Ledien, protein C deficiency, etc.), recent surgery, malignancy, and cirrhosis. In addition, up to 50% of patients will have a history of deep vein thrombosis.

Question 6

Mesenteric artery thrombosis

Answer 6

Worst prognosis (mortality 90%), because usually originates proximal SMA and leads to bowel necrosis
Risk Factors: systemic atherosclerosis and old age.
-Slow progression of atherosclerosis in the mesenteric vasculature until a certain level of blockage is obtained leading to bowel ischemia and infarction
- Celiac trunk most commonly affected
- History of undiagnosed chronic mesenteric ischemia with vague and insidious symptoms such as weight loss, abdominal angina (abdominal pain after meals), diarrhea, and fear of food.

Question 7

Non-occlusive ischemia

Answer 7

• Occurs in low flow states in absence of an arterial or venous occlusion.
• Etiology: Any condition associated with decreased cardiac output can cause non-occlusive ischemia including cardiogenic shock, congestive heart failure, and arrhythmias. Sepsis, hypotensive states, and drugs inducing mesenteric vasoconstriction (Digoxin, Cocaine, Alpha-agonists, Beta-blockers) can also be causes.
• Usually occurs in patients already in the hospital who are very sick.

Question 8

Laboratory testing

Answer 8

Largely unhelpful or at least nonspecific.

• Elevated Lactate probably the best, but does not elevate till shortly after bowel has already infarcted
• D-dimer has a higher sensitivity than lactate
• Low specificity for both though

Question 9

What is the gold standard imaging?

Answer 9

Angiography is the gold standard for mesenteric ischemia allowing for diagnosis and therapy

Question 10

What is an alternate imaging?

Answer 10

• CT angiography abdomen/pelvis
  CTA is being considered the initial test to obtain for patients in who the diagnosis of mesenteric ischemia is being considered.
  However cannot provide therapy like angiography can.
  However, may help triage patients who need Angiography vs Surgery

Question 11

General Treatment

Answer 11

• Start Broad spectrum antibiotics
• If a thrombus is suspected, an anticoagulant such as heparin should be started to halt propagation of the thrombus. Heparin can be shut off quickly if the patient is taken to the OR.
• The ultimate management of acute mesenteric ischemia is challenging and ever changing.

Question 12

Treatment of Mesenteric Artery Embolus

Answer 12

Embolectomy and bowel visualization to assess for signs of necrosis.

• Percutaneous treatment with thrombolytics directly infused into the artery containing the embolus during angiography is another option
• If operative management is decided, revascularization is done first so that any ischemic-looking bowel can recover with the return of blood flow. Once blood flow is reestablished, any bowel that remains infarcted and necrotic is then resected.

Question 13

Treatment of Mesenteric Artery Thrombosis

Answer 13

• heparin should be started as soon as the diagnosis is made and prior to surgery
• Operative management is the same as for mesenteric artery embolus
• For non-operative candidates, percutaneous transluminal angioplasty is done.

Question 14

Treatment of Mesenteric Vein Thrombosis

Answer 14

• If there are signs of infarction, then operative care is required. Otherwise thrombectomy with endarterectomy or distal bypass is the first choice of treatment.
• Then lifelong anticoagulation

Question 15

Treatment of non-occlusive mesenteric ischemia

Answer 15

• Correct the underlying cause of the low flow state to the bowel whether it be sepsis or decreased cardiac output.
• Papaverine can help treat the vasoconstriction of the vessels to the mesentery which will maximize blood flow.
• Patients who develop peritoneal signs must go to the OR.