Acute Mesenteric Acute Mesenteric Ischemia:Ischemia:

Diagnostic approach and managementDiagnostic approach and management

Dr. Law Siu KingDr. Law Siu KingDepartment of Department of

surgery surgery United Christian United Christian

HospitalHospital

www.surgical-tutor.org.uk

Acute mesenteric Acute mesenteric ischemiaischemia

It is a syndrome It is a syndrome in which inadequate blood flow through in which inadequate blood flow through

the mesenteric circulation causes the mesenteric circulation causes ischemia and eventual gangrene of the ischemia and eventual gangrene of the bowel wall. bowel wall.

Acute mesenteric Acute mesenteric ischemiaischemia

It is uncommon but life-threatening It is uncommon but life-threatening diseasedisease

Incidence ~1 in every 1000 hospital Incidence ~1 in every 1000 hospital admissionsadmissions11

Mortality remains as high as 60-80% Mortality remains as high as 60-80% 11

1. Mark et al Semin Vasc Surg 23:9-20 ,2010

Acute Mesenteric Acute Mesenteric IschemiaIschemia

Early Diagnosis is importantEarly Diagnosis is important to decrease mortality to decrease mortality 11

1.Inderbitzi et al Eur J Surg 1992;158: 123-126

Acute mesenteric Acute mesenteric ischemiaischemia

It can be classified It can be classified according to its according to its etiologyetiology SMA embolismSMA embolism SMA thrombosisSMA thrombosis Non-occlusive Non-occlusive

mesenteric mesenteric ischemia (NOMI)ischemia (NOMI)

Mesenteric venous Mesenteric venous thrombosisthrombosis

SMAthrombosis

25%

SMAembolism 50%

Acutemesenteric

venousthrombosis(AMVT) 5%

Non-occlusivemesentericischemia

(NOMI) 20%

Oldenburg et al Arch Intern Med 2004;164:1054-1062

Incidence(%)

Risk factors

SMA Embolism 50 Recent MICHFArrhythmiaRheumatic fever

SMA Thrombosis 25 Systemic atherosclerosis

Non-occlusive mesenteric ischemia

20 Cardiogenic shockCardiopulmonary bypassVasopressor agentsSepsis, burnPancreatitis

Mesenteric venous thrombosis

5 HypercoagulabilityPortal HTInflammationPrior surgeryTrauma

Oldenburg et al Arch Intern Med 2004;164:1054-1062

PresentationPresentation

Classical description of early Classical description of early symptomsymptom Abdominal pain that is out of proportion Abdominal pain that is out of proportion

to physical findingsto physical findings However, classic presentation may absence However, classic presentation may absence

in 20-25% of cases.in 20-25% of cases.

Kazmers et al Ann Vas surg 12:187-197,1998

PresentationPresentation

EarlyEarly Prominent Prominent

symptoms of GI symptoms of GI emptying ( nausea, emptying ( nausea, vomiting , vomiting , diarrhea )diarrhea )

LateLate Bloody diarrhea Bloody diarrhea Abdominal Abdominal

distensiondistension FeverFever ShockShock PeritonitisPeritonitis

Early diagnosis requires high

index of suspicion Park et al J Vas 2002;

35:445-52

Sereedharan et al Singapore Med J 2007;48(4):319

Patient presents with severe abdominal pain consistent with ischemic bowel

Obtain history and perform physical examination.Pain is out of proportion to physical findings is a significant clue.

Look for risk factors for acute mesenteric ischemia.

InvestigationInvestigation

Blood test:Blood test: Most common Most common

laboratory laboratory abnormalities are:abnormalities are: haemoconcentrationhaemoconcentration LeucocytosisLeucocytosis Metabolic acidosisMetabolic acidosis Lactic acidosis (in more Lactic acidosis (in more

advanced case)advanced case) Other serum markersOther serum markers

Raised Raised amylaseamylase ALPALP

Imaging:Imaging: AXR:AXR: Features suggestive Features suggestive

bowel infarctionbowel infarction dilated thickened bowel dilated thickened bowel

loopsloops a ground-glass a ground-glass

appearanceappearance ““Thumb-printingThumb-printing””, , toxic dilatation toxic dilatation gas in bowel wall, gas in bowel wall,

portal veins or portal veins or peritoneumperitoneum

25% patients had 25% patients had normal AXRnormal AXR

Neither sensitive nor specific.

But Ix help exclude other DDxMark et al Semvassurg 200912002

Diagnostic imagingDiagnostic imaging

Mesenteric AngiographyMesenteric Angiography Gold standardGold standard Sensitivity 90-100%, specificity 100%Sensitivity 90-100%, specificity 100%11

1. Brandt et al Sleisenger and Fordtran’s Gastrointestinal and liver disease, 2002: 2321-40

2. Hiroshi et al Surg Today (2005) 35:185–195

2

Angiographic featuresAngiographic features

SMA embolismSMA embolism11 SMA thrombosisSMA thrombosis22 Non-Occlusive Non-Occlusive Mesenteric IschemiaMesenteric Ischemia22

1.Timothy et al SemVasSurg Semin Vasc Surg 23:29-352. ACS surgery : principles and practice

Other imaging modalitiesOther imaging modalities

Standard CT abdomen Standard CT abdomen with contrastwith contrast Specificity 92%, Specificity 92%,

sensitivity 64%sensitivity 64%11

Sensitivity acute MVT Sensitivity acute MVT (100%), chronic (100%), chronic MVT(93%)MVT(93%)

Multidetector CT Multidetector CT arteriography (MDCTA)arteriography (MDCTA) Specificity 94%Specificity 94% Sensitivity 96%Sensitivity 96%22

Exclude other pathologyExclude other pathology

Duplex USGDuplex USG Excellent specificity (92-100% )Excellent specificity (92-100% ) But sensitivity is limited (70-89%)But sensitivity is limited (70-89%) Operator dependentOperator dependent

Magnetic resonance angiographyMagnetic resonance angiography Without cx of iodinated contrastWithout cx of iodinated contrast Sensitivity 100%, Specificity 91%Sensitivity 100%, Specificity 91%

1.Taourel et al Radiology 1996; 199 :632-6

2.Kirkpatrick et al Radiology 229:91-98, 2003

CT featuresCT features

SMA occlusion with embolus

1.Aschoff et al Abdom Imaging 34:345-357,2009

Gas in portal venous system

SMA thrombosis

Extensive Pneumatosisintestinalis2.http://

www.learningradiology.com/notes/ginotes/mesentericischemiapage.htm

CTA vs Conventional CTA vs Conventional Angiography?Angiography?

CTACTA AdvantagesAdvantages

Non-invasiveNon-invasive readily availablereadily available Allow exclude other Allow exclude other

DDx of acute abdomenDDx of acute abdomen Preferred modality for Preferred modality for

Dx MVT (90% Dx MVT (90% sensitivity )sensitivity )

Conventional Conventional AngiographyAngiography Advantage:Advantage:

High sensitivity and High sensitivity and specificityspecificity

Therapeutic role for Therapeutic role for infusion therapyinfusion therapy

Disadvantage:Disadvantage: InvasiveInvasive Less easily availableLess easily available second-line study in second-line study in

patients with a strong patients with a strong suspicion of MVT suspicion of MVT

Increase use of CTA in diagnosis of acute mesenteric ischemia

Bradbury et al The British Journal of surgery 82(11): 1446-1459,1995

Patient presents with severe abdominal pain consistent with ischemic bowel

Obtain history and perform physical examination.Pain is out of proportion to physical findings is a significant clue.Look for risk factors for acute mesenteric ischemia.Order investigative studies:Laboratory tests: WBC count, lactate, ASTImaging: abdominal X-ray, duplex ultrasonography, CTA, MRA

Acute mesenteric ischemiaPeritoneal sign is present Peritoneal sign is absence

Principles of Principles of managementmanagement

Early recognition and interventionEarly recognition and intervention Fluid resuscitation and correction of Fluid resuscitation and correction of

electrolytes disturbanceelectrolytes disturbance Nasogastric tube Nasogastric tube

for decompression of bowelfor decompression of bowel Broad spectrum antibiotics Broad spectrum antibiotics

to cover bacterial translocationto cover bacterial translocation Hemodynamic status monitoring( Foley Hemodynamic status monitoring( Foley

catheter, CVP, A line )catheter, CVP, A line ) Definitive Tx depends on its etiologyDefinitive Tx depends on its etiology

Surgical explorationSurgical exploration

Surgical exploration if evidence of Surgical exploration if evidence of intestinal infarction/ with intestinal infarction/ with peritonitisperitonitis.. Allow assessment of Allow assessment of bowel viabilitybowel viability Identify underlying Identify underlying causes of diseasecauses of disease Resection necrotic bowelResection necrotic bowel Perform Perform revascularizationrevascularization if appropriate if appropriate

Assess pulse in SMA

Weak pulse Normal pulse

Proximal jejunum and transverse colon

are spared from ischemia

Diffuse midgut bowel ischemia is noted

Suggestive SMA Embolism Suggestive SMA thrombosis

Suggestive Non-occlusive

mesenteric ischemia

SuggestiveMesenteric

Venous thrombosis

Weak pulse No pulse

Pulse present proximally but not distally

Kazmers et al Ann Vas surg 12:187-197,1998

Revascularization Revascularization procedureprocedure

SMA embolismSMA embolism SMA embolectomySMA embolectomy +/- SMA patch +/- SMA patch

angioplastyangioplasty

Kazmers et al Ann Vas Surg 12:187-197,1998

Revascularization Revascularization procedureprocedure

SMA thrombosisSMA thrombosis Mesenteric bypass Mesenteric bypass 11

retrograde (from retrograde (from iliac artery or iliac artery or infrarenal aorta to infrarenal aorta to SMA) SMA)

antegrade ( from antegrade ( from supraceliac aorta to supraceliac aorta to SMA) SMA)

Reimplantation of Reimplantation of SMA to aortaSMA to aorta22

1.Kazmers et al Ann Vasc Surg 1998;12:187-1972.Kieny R et al Ann Vasc Surg 1990;8(4):495-500

How can we assess bowel How can we assess bowel viability ?viability ?

Direct inspectionDirect inspection Visible & palpable pulsations in mesenteric arcade, Normal colour and appearances of the bowel serosa, Peristalsis Bleeding from cut surfaces Sensitivity of 82%, specificity of 91%

IV fluorescein Administer IV sodium fluorescein (1g) and inspect bowel

under ultraviolet (Wood’s) lamp. Viable bowel has smooth, uniform fluorescence

Doppler Assessment of antimesenteric intestinal arterial flow

Kazmers et al Ann Vas Surg 12:187-197,1998

IV fluorescein Administer IV sodium fluorescein (1g) and

inspect bowel under ultraviolet (Wood’s) lamp. Viable bowel has smooth, uniform

fluorescence Doppler

Assessment of antimesenteric intestinal arterial flow

Who should have second Who should have second look laparotomy? look laparotomy?

Some surgeons Some surgeons advocate advocate routine routine second-look second-look laparotomylaparotomy at 24- at 24-48hr48hr Claimed reduced Claimed reduced

mortality ratemortality rate

Other adopt a Other adopt a selective approachselective approach and perform a and perform a second laparotomy second laparotomy when patient when patient deterioates deterioates clinically.clinically. Can avoid Can avoid

unnecessary second unnecessary second operation if patient operation if patient remains wellremains well

Bradbury et al The British Journal of Surgery Vol 82(11), November 1995

Endovascular Techniques in Endovascular Techniques in Acute arterial mesenteric Acute arterial mesenteric

ischemiaischemia Aspiration embolectomyAspiration embolectomy11

SMA thrombolysisSMA thrombolysis22

StentingStenting of visceral of visceral arteries in acute arteries in acute mesenteric ischemiamesenteric ischemia33

Hybrid approach to SMAHybrid approach to SMA stenting for SMA stenting for SMA thrombosisthrombosis44

Combination of open Combination of open exploration +endovascular exploration +endovascular approach with retrograde approach with retrograde open mesenteric stentopen mesenteric stent

1.Acosta et al, Cardiovasc Intervent Radiol 32:895-905,20092.Schoots et al, J Vasc Interv Radiol 16:317-329,20053.Gartenschlaeger. Cardiovasc Intervent Radiol 31:398-400,20084.Wyers et al, J Vasc Surg 45:269-275,2007

Case series have been shown that endovascular approaches were feasible

Management of Mesenteric Management of Mesenteric venous thrombosisvenous thrombosis

Anticoagulation Anticoagulation is mainstay of is mainstay of treatmenttreatment

Workup for hypercoagulability .Workup for hypercoagulability . Laparotomy if peritoneal signs Laparotomy if peritoneal signs

develop. develop. Resection of necrotic bowelResection of necrotic bowel Thrombectomy ( few case reports only ) Thrombectomy ( few case reports only )

1.Bradbury et al The British Journal of Surgery Vol 82(11), November 1995

Management of non-Management of non-occlusive mesenteric occlusive mesenteric

ischemiaischemia Correct underlying Correct underlying

condition.condition. Optimize fluid status, Optimize fluid status,

improve cardiac output, improve cardiac output, and eliminate vasopressors.and eliminate vasopressors.

Consider Consider catheter-directed catheter-directed intraarterial infusion of intraarterial infusion of vasodilatorvasodilator (papaverine) (papaverine)

Laparotomy if peritoneal Laparotomy if peritoneal signs developsigns develop

Bradbury et al The British Journal of Surgery Vol 82(11), November 1995

ACS surgery : principles and practice

Clinical suspicion

Acute mesenteric ischemiaPeritoneal sign present Peritoneal sign absent

Surgical exploration CT +/- CT angiography or conventional angiography

SMA embolism SMA thrombosisNon-occlusive

Mesenteric ischaemiaMesenteric Venous

Thrombosis

Surgical exploration Thrombolytic if operative risk is high

Intra-arterial papavarineSearch for

hypercoagulable state

Clinical improvementClinical

no improvement

Observe Surgical exploration

AnticoagulationWith heparin

Peritoneal signObserve

if asymptomatic

Thank YouThank You

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