1. Acute Mesenteric Ischemia
Scott Q. Nguyen, M.D.
Celia M. Divino, M.D.
Mount Sinai School of Medicine
Department of Surgery

2. Mrs. Mitty
An 83 year-old woman is brought to the ER by ambulance from her nursing home w/ a 4 hour history of severe diffuse abdominal pain and distention.

3. What other points of the history do you want to know?

4. Consider the Following
History, Mrs. Mitty
Consider the Following
Characterization of symptoms
Temporal sequence
Alleviating / Exacerbating factors:
Pertinent PMH, ROS, MEDS.
Associated signs and symptoms
Relevant family hx.

5. History, Mrs. Mitty Characterization of Symptoms:
Sudden onset diffuse abdominal pain and distention hours ago.
Pain not localized to any quadrant.
Alleviating / Exacerbating factors:
Pain is excruciating, it’s the worse she’s ever experienced
Nothing alleviates it
Associated signs/symptoms:
She vomits 1L of feculent emesis on arrival to ER.
Last BM 2 hours ago, loose

6. Other History
PMH
Atrial Fibrillation - dx’d 1 month ago, anticoagulation contraindicated with history of massive GI bleed
CHF, CAD, DM
PSH
Cholecystectomy, left hemicolectomy for diverticular disease
MEDS
digoxin, metoprolol, insulin

7. Other History Family History Social History Occasional wine,
50 pack-yr smoker, quit 2 yrs ago
Family History
Patient unable to give

8. What is your Differential Diagnosis?

9. Differential Diagnosis Based on History and Presentation
Small Bowel Obstruction
Acute Mesenteric Ischemia
Perforated Diverticulitis
Ischemic Colitis
Perforated Peptic Ulcer Disease
Acute Pancreatitis
Acute Cholecystitis
Gastroenteritis
Acute Appendicitis

10. Physical Examination
What would you look for?

11. Physical Examination
Vital Signs: T = 38.5, P = 103, BP = 140/85, RR = 28
Appearance: thin , in severe distress, legs pulled up to chest, moaning
Heart: irregularly irregular
Lungs: mild rales at bases
Abdomen: decreased BS, very distended, mildly tender diffusely, no guarding/rebound tenderness, no hernias
Rectal: loose stool in vault, streaked w/ fresh blood
Remaining Examination findings non-contributory

12. Would you like to revise your Differential Diagnosis?
Strangulated small bowel obstruction
Acute Mesenteric Ischemia
Ischemic Colitis

13. Laboratory
What would you obtain?

14. Labs ordered, Mrs. Mitty LFTs - WNL Amylase/Lipase - 89/9514 30
133
101 18
405
240 42
1.2
4.9 19
85 PMN’s 22 Bands
LFTs - WNL
Amylase/Lipase - 89/95
PT/PTT /33.0
ABG /30/69/16
Lactate 7.9
CBC 18/14/42/405
Electrolytes: 133/4.9/101/19/30/1.2/240

15. Lab Results, Discussion
Leukocytosis - acute process, possibly infectious
Electrolytes - elevated BUN indicating dehydration or 3rd spacing.
Anion gap acidosis - intravascular depletion, Metabolic acidosis (lactic acidosis)
Coags –abnormal coags may reflect sepsis. Pt. not on anticoagulation for Afib.
Normal LFTs/ pancreatic enzymes - no signs of hepatic/pancreatic insult

16. Interventions at this point?

17. Consider the following Interventions
Admit to the hospital/ICU
Aggressive resuscitation
Start IV with isotonic crystalloid solution ( NS or LR)
Insert Foley catheter
Monitor response to resuscitation
Administer broad spectrum antibiotics
Likely intra-abdominal septic process

18. What further studies would you want at this time?

19. Studies, Mrs. Mitty Abdominal X-rays Flat / Upright
Acute Abdominal Series (may include chest at some institutions)

21. Studies – Results Plain abdominal films
Diffuse dilation of small bowel w/ air fluid levels on upright view. Some air in Left colon and Rectum. NO free air

22. What is the differential diagnosis at this point?

23. Revised Differential Diagnosis
Acute Mesenteric Ischemia
Strangulated small bowel obstruction
Diverticulitis w/ contained perforation?

24. What next?

25. What next?
Mesenteric Angiogram or CT Angiogram

26. Discussion
With the sudden onset of symptoms, h/o Afib, and “pain out of proportion to physical exam,” acute mesenteric ischemia should be high on the Differential Diagnosis
A mesenteric angiogram will allow visualization of the visceral vessels (celiac, SMA, IMA)
Mesenteric angioram may allow access to vasodilators if non-occlusive disease is present

27. Mesenteric Angiogram
Note complete lack of contrast in mesenteric vessels in AP view (left). The occluded origins of the celiac axis and superior mesenteric artery are demonstrated in the Lateral view (right).

28. CT Angiogram
Note complete occlusion and lack of IV contrast filling the superior mesenteric artery from its origin from the aorta (Arrows).

29. CT angiogram / MR angiogram
Other studies
CT angiogram / MR angiogram
sensitivity 75%, specificity 100% for emboli
additionally can detect thickened, distended bowel loops
more sensitive for Mesenteric Venous Thrombosis

30. What should be done next?
Management
What should be done next?

31. Management Pre-operative preparation Urgent exploration
Assure adequate resuscitation
Monitoring
Foley Catheter
Urgent exploration
Surgical embolectomy
Assess bowel viability

32. Management Pre-operative preparation
Assure adequate resuscitation
Monitoring
Non-invasive: EKG, BP, Pulse Oximetry, foley catheter
Consider invasive monitoring: Central venous catheter, PA Catheter ? Arterial line?
Operative Technique/ Urgent exploration
Midline Laparotomy
Relevant Anatomy
Surgical Embolectomy
Assess bowel viability

33. Necrotic bowel from mesenteric ischemia.
Surgical Embolectomy
Pack bowel to Right, Expose SMA
Arteriotomy
Pass balloon embolectomy catheter
Assess bowel viability
Resect if necessary
Necrotic bowel from mesenteric ischemia.

34. Discussion
Acute mesenteric ischemia is a vascular emergency with overall mortality 60-80%. There are four main pathophysiologic processes which have the same common endpoint, bowel necrosis, abdominal sepsis, and death. Mesenteric arterial anatomy is notable for rich collateral flow between the celiac trunk, superior mesenteric artery, and inferior mesenteric artery. Gradual occlusion of 2 of the 3 vessels is tolerable as rich collateral branches form between these. Acute occlusion of any of the vessels or their branches causes acute intestinal ischemia and necrosis.

35. Discussion The four processes:
1) Acute arterial embolus -usually from cardiogenic embolus in pts w/ Afib or valvular disorders. SMA is the common vessel affected as it has a less acute take off from aorta
2) Acute arterial thrombosis - chronic atherosclerotic plaque at origin of vessel acutely thromboses
3) Chronic mesenteric ischemia - atherosclerosis of visceral vessels results in abdominal pain (intestinal angina) during times of increased blood demand (digestion)
Acute venous occlusion - venous thrombosis causes cessation of venous outflow from intestines
*Non-occlusive mesenteric ischemia can also be seen in low-flow states

36. Discussion
Diagnosis - requires high degree of suspicion. Classically presents as “pain out of proportion to physical exam” or severe pain w/o peritoneal signs. The history of Cardiac disease, valvular disease, or Afib should alert one to an embolic disease. Gold standard for diagnosis is mesenteric angiogram, but CT angiogram is more and more being used.
Treatment - requires aggressive resuscitation and hemodynamic monitoring as patients become critically ill very quickly. Urgent surgery w/ viseral revascularization (embolectomy, thrombectomy, endarterectomy, or bypass) is required. After this, evaluation of viability of bowel segments should be performed with resection of any necrotic portions.

37. QUESTIONS ??????

38. References Townsend CM. Sabiston Textbook of Surgery. 17th Edition
Cameron JL. Current Surgical Therapy. 8th Edition
Oldenburg et al. Acute Mesenteric Ischemia. Arch Intern Med 164:

39. Acknowledgment
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