1. Management of Acute Mesenteric Ischemia
CN Shum (2nd Year HST)
Department of Surgery
Pamela Youde Nethersole Eastern Hospital

2. Definition of Mesenteric Ischemia
Interruption of intestinal blood flow by
embolism,
thrombosis, or
a low-flow state.

3. Pathophysiology

4. How common is Mesenteric Ischemia?
0.1% of all hospital admissions.
Mesenteric artery stenosis is found in 17.5% of independent elderly adults.
Cappell MS, et al. Gastroenterol Clin North Am. Dec 1998;27(4):827-60, vi. 
Ha C, et al.  Am J Gastroenterol. Jun 2009;104(6):  

5. Classification of Mesenteric Ischemia
Acute
4 distinct mechanisms
Chronic
Due to long standing atherosclerosis

6. Causes of Acute Mesenteric Ischemia (AMI)
Type
Risk Factors
Mesenteric Arterial Embolus (MAE)
(> 50%)
Coronary artery disease, heart failure, valvular heart disease, atrial fibrillation, history of arterial emboli
Mesenteric Arterial thrombosis (MAT)
(10%)
Generalized atherosclerosis
Mesenteric Venous thrombosis (MVT)
(5–15%)
Hypercoagulable state, inflammatory conditions (eg, pancreatitis, diverticulitis), trauma, heart failure, renal failure, portal hypertension, decompression sickness
Non-Occlusive Mesenteric Ischemia (NOMI)
(25%)
Low flow states (eg, heart failure, shock, cardiopulmonary bypass) and splanchnic vasoconstriction (eg, vasopressors, cocaine)

7. Clinical presentation of Acute mesenteric Ischemia

8. Symptoms & signs
In a series of 58 patients with mesenteric ischemia due to mixed causes:
abdominal pain 95%
Nausea 44%
vomiting 35%
diarrhea 35%
heart rate > %
Shock 33%
metabolic acidosis 33%
'blood per rectum‘ 16%
Constipation 7%
Park WM, et al. J. Vasc. Surg. 35 (3): 445–52.

9. Acute Mesenteric Ischemia due to embolisation
F:M=2:1
Median age 70
Typical presentation
Sudden onset of periumbilical pain
Followed by copious vomiting and explosive diarrhoea
Abdominal signs
Early: non-specific
Late (likely infarction): Peritonism, Blood in stool or vomitus

10. Acute Mesenteric Ischemia due to thrombosis
Often a history of
intestinal angina
nausea
Sitophobia
significant wt loss

11. Acute Mesenteric Ischemia due to venous thrombosis
Insidious onset over weeks
Nausea, anorexia, diarrhoea
Later clinical course
Diffuse abd pain

12. Acute Mesenteric Ischemia due to nonocclusive disease
Occurs in patient with wide-spread vasoconstriction
Critically ill
Shock
vasopressors

13. Diagnostic Investigations

14. Blood tests Elevation of Metabolic acidosis WCC Amylase Phosphate
Increases within 4 hours (75%)
Reference:
Can J Surg Jan;22(1):40-5
Metabolic acidosis

15. Plain XRay Non-specific dilatation of bowel Late signs:
Thumb-printing (edematous bowel wall)
Pneumatosis intestinalis
Portal venous gas

16. Thumb-printing

17. Pneumatosis Intestinalis

18. Portal Venous Gas

19. Doppler USG Able to identify severe stenosis or total occlusion:
Sensitivity 70-89%
Specificity %
Unable to detect
emboli beyond the proximal main vessel
NOMI
J Vasc Surg 14 (1991), pp. 511–518.
J Vasc Surg 14 (1991), pp. 780–786.

20. Angiography Non-invasive Invasive CTA MRA Catheter Advantages:
Better spatial resolution
Faster acquisition time
MRA
No radiation
No need of iodinated contrast
Invasive
Catheter
AJR 2007; 188:
*J Gastrointest Surg Dec;9(9):

21. Treatment of Acute Mesenteric Ischemia
…slightly varied depending of its causes

22. Treatment in general

23. Role of anticoagulation dependent on causes of AMI
Immediate after dx
Early post-op
Long term
Arterial embolism
Yes
Arterial
thrombosis
Venous
(esp if underlying hypercoagulability uncovered)
Non-occlusive
Surgery 101 (1987), pp. 383–388.
Am Surg 57 (1991), pp. 573–578.
Ann Surg 161 (1965), pp. 516–523.

24. Role of vasodilators Experiences mainly on papaverine For NOMI
Others:
tolazoline, glucagon, nitroglycerin, nitroprusside, prostaglandin E, phenoxybenzamine, and isoproterenol
For NOMI
Mainstay of tx
Reduce mortality from 70-90% to 0-55%
For Occlusive MI
Adjunct
Not practiced universally
Am J Radiol 142 (1984), pp. 555–562.
Surgery 82 (1977), pp. 848–855.
Curr Top Surg Res 3 (1971), pp. 425–433.
Br J Surg 77 (1990), pp. 601–603.

25. Role of Interventional Radiology
Options
Application
Remarks
Catheter directed infusion of vasodilators
Primary treatment in NOMI
Catheter directed thrombolysis
Anecdotal use in Occlusive MI
Measures to ensure bowel viability e.g. Laparoscopy
Angioplasty
AMI: scant
CMI: common
Regan, F,et al. Am. J. Gastroenterol. 91(5):1019–1021, 1996.
Jamieson, A.C., et al. Aust. N. Z. J. Surg. 49:355–356, 1979.
Flickinger, E.J., et al. Am. J. Roentgenol. 140:771–773, 1983.
Rivitz, S.M., et al. J. Vasc. Interv. Radiol. 6(2):219–223,1995.
Rijs, J., et al. Acta. Chir. Belg. 97(5):247–249, 1997.
Train, J.S., et al. J. Vasc. Interv. Radiol. 9(3):461–464, 1998.
Poplausky, M.R., et al. Gastroenterology 110(5):1633–1635, 1996.
Walsh, R.M., et al. Surg. Endosc. 12(12):1405–1409, 1998.

26. Case reports and small series of use of thrombolytic agents for SMA emboli
Study (yr)
No. of patient
Partial
Occlusion
Total
Central
Location
Peripheral
Streptokinase
Urokinase
rtPA
Outcome
Badiola and Scoppetta54 (1997) 1 +
Successful
Bonardelli et al.55 (1994)
Embolectomy, resection
Boyer et al.56 (1994)
Flickinger et al.57 (1983)
Embolus lysed; pt died of CHF
Gallego et al.67 (1996) 2
Successful by 4 hr
Hillers et al.58 (1990)
Hirota et al.59 (1997)
Kwauk et al.60 (1996)
McBride and Gaines61 (1994)
Pillari et al.62 (1983)
Successful by 36 hr
Ramirez et al.63 (1990)
Regan et al.64 (1996)
Rodde et al.65 (1991)
Schoenbaum et al.68 (1992) 4
Resection needed in 1 patient
Sicard et al.69 (1984)
Simo et al.70 (1997) 10
Embolysis 90%; Clinical success 70%; Laparotomy 30%
Turegano Fuentes et al.71 (1995)
Vujic et al.66 (1984)
Successful by 30 h r

27. Role of surgery Allow assessment of bowel viabiltiy
Allow resection of non-viable bowel
Allow specific procedure
Types of AMI
Specific surgical procedure
MAE
Embolectomy
MAT
Bypass
MVT
Venous thrombectomy is not usually recommended
as it often recurs and results in distal diffuse extention
(Surg Clin North Am 1997;77:327–38.)
NOMI No

28. Laparotomy findings in arterial embolism
Location of embolism
usually just distal to the middle colic artery
Sparing
proximal jejunum & distal large bowel
Next procedure:
Embolectomy

29. Embolectomy
(A) Exposure of superior mesenteric artery by reflection of Ligament of Treitz.
(B) A transverse arteriotomy is performed transversely, proximal to the middle colic branch of the superior mesenteric artery.
(C) Embolectomy is performed with a 4-F embolectomy catheter.
(D) Artery is closed with interrupted praline suture. 
Kazmers A: Ann Vasc Surg 12:191, 1998.

30. Laparotomy findings in arterial thrombosis
Location of thrombosis
usually at the origin of SMA
No sparing
the entire small bowel and proximal large bowel appear ischemic
Next procedure
Bypass

31. Bypass

32. After revascularization (embolectomy or bypass)
Alert anesthetist before reperfusion
can lead to sudden physiologic and metabolic derangements, including hypotension, hyperkalemia, and profound acidosis.
Consider postrevascularization papaverine

33. After reperfusion

34. For non-viable looking bowel
Frankly necrotic bowel segments
resection
Marginal-viable bowel
may improve over hours
consider second-look laparotomy

35. Prognosis
Depends on time & type

36. Mortality rates for AMI
Study (yr)
No. of patients
Mortality rate (%)
Braun2 (1985) 52 64
Clavien et al.3 (1987) 81 83
Cohen Solal et al.4 (1993) 30 67
Finucani et al.5 (1989) 32 66
Georgiev6 (1989)
175 93
Inderbitzi et al.7 (1992)
100 68
Kach and Largiader8 (1989) 45 60
Koveker et al.9 (1985) 39 85
Levy et al.10 (1990)
92* 59
Mishima11 (1988)
162 65
Ritz et al.12 (1997)
141 71
Voltolini et al.13 (1996) 47 72
Zan et al.14 (1993)
*Patients with NOMI excluded.

37. Studies showing the importance of early diagnosis of AMI on survival
Study (yr)
No. of patients
Mortality %
(No gangrene )
Mortality % (Gangrene )
(<24H of symptoms)
(>24H of symptoms)
Batellier and Kieny15 (1990) 65 25 68
Boley et al.18 (1981) 47 57 73
Inderbitzi et al.7 (1990) 83
17 (a) 88
Kieny16 (1990) 98 26 71
Lazaro et al.17 (1986) 23 75
Levy et al.10 (1990) 92 31
Ritz et al.12 (1997)
141
44 (b)
Vellar and Doyle19 (1977) 52 54 95
a<12 hours, mortality = 0%. b<12 hours, mortality = 0%.

38. Mortality of different types of AMI
arterial embolism 54%
arterial thrombosis 77%
venous thrombosis 32%
non-occlusive ischemia 73%
Brandt LJ, Boley SJ (2000). “AGA technical review on intestinal ischemia. American Gastrointestinal Association”. Gastroenterology 118 (5): 954–68.
Schoots IG, Koffeman GI, Legemate DA, Levi M, van Gulik TM (2004). "Systematic review of survival after acute mesenteric ischaemia according to disease aetiology". The British journal of surgery 91 (1): 17–27.

39. Acute Mesenteric Ischemia
Surgical emergency

40. Thankyou
PYNEH
CN Shum