ischemia and infarction

1. Acute MesentericAcute Mesenteric
Ischemia and InfarctionIschemia and Infarction
Dr. Sajad Ali (MBBS., MS.)Dr. Sajad Ali (MBBS., MS.)
Gastrointestinal & LaparoscopicGastrointestinal & Laparoscopic
surgeonsurgeon
Dr Ahmed Abanamy HospitalDr Ahmed Abanamy Hospital

2. A First Big Distinction…A First Big Distinction…
 Mesenteric IschemiaMesenteric Ischemia – ischemia of the– ischemia of the
small bowelsmall bowel, usually 2/2 an acute cause, usually 2/2 an acute cause
involving the SMA or SMV.involving the SMA or SMV.
 Ischemic colitisIschemic colitis – ischemia of the– ischemia of the coloncolon,,
rarely with a known acute precipitatingrarely with a known acute precipitating
cause.cause.

3. Superior Mesenteric Artery (SMA)Superior Mesenteric Artery (SMA)
 Largest caliber vessel + 45-degree angleLargest caliber vessel + 45-degree angle
makes it most commonly occludedmakes it most commonly occluded
Celiac Trunk
IMA
SMA
Aorta

4. Superior Mesenteric Artery (SMA)Superior Mesenteric Artery (SMA)
 Emboli occlude past the middle colic,Emboli occlude past the middle colic,
causing small bowel ischemiacausing small bowel ischemia
SMA
Middle Colic
Right Colic
Ileocolic
Jejunal & Ileal
Arteries
Occlusion
Point

5. Etiologies of Acute MesentericEtiologies of Acute Mesenteric
Ischemia (AMI)Ischemia (AMI)
 SMA Occlusion (at least 60% of cases)SMA Occlusion (at least 60% of cases)
 Embolism: MI, Afib, Endocarditis, Valve d/oEmbolism: MI, Afib, Endocarditis, Valve d/o
 Thrombosis: Atherosclerosis – plaque ruptureThrombosis: Atherosclerosis – plaque rupture
 Nonocclusive Mesenteric IschemiaNonocclusive Mesenteric Ischemia
(NOMI)(NOMI)
 Atherosclerosis + shock + vasopressorsAtherosclerosis + shock + vasopressors
 Mesenteric Venous Thrombosis (MVT)Mesenteric Venous Thrombosis (MVT)
 Primary clotting disorderPrimary clotting disorder

6. Etiologies of Acute MesentericEtiologies of Acute Mesenteric
Ischemia (AMI)Ischemia (AMI)
 Focal small bowel ischemia - rareFocal small bowel ischemia - rare
 Partial malrotation, volvulus, mesentericPartial malrotation, volvulus, mesenteric
hematoma, strangulated herniahematoma, strangulated hernia
 UnknownUnknown
 ?Mesenteric small vessel disease?Mesenteric small vessel disease

7. History & PhysicalHistory & Physical
Classic Presentation:
 Rapid onset of severe, unrelenting
periumbilical pain
 Pain out of proportion to findings on
physical examination.
 Nausea and vomiting
 Forceful/urgent bowel evacuation
 Risk factors for acute mesenteric ischemia

8. History & PhysicalHistory & Physical
SMA Thrombosis:SMA Thrombosis:
 Prodrome of postprandial pain/nauseaProdrome of postprandial pain/nausea
and weight lossand weight loss
 Presentation with classic symptomsPresentation with classic symptoms
Non-occlusive Mesenteric Ischemia:Non-occlusive Mesenteric Ischemia:
 Unexplained decline in clinical status orUnexplained decline in clinical status or
failure to follow expected recoveryfailure to follow expected recovery

9. History & PhysicalHistory & Physical
Mesenteric Venous Thrombosis:Mesenteric Venous Thrombosis:
 FeverFever
 Abdominal distensionAbdominal distension
 Hemoccult positive stoolHemoccult positive stool

10. Laboratory FindingsLaboratory Findings
 Anion gap metabolic acidosisAnion gap metabolic acidosis
 Elevated arterial/venous lactateElevated arterial/venous lactate
 LeukocytosisLeukocytosis
 HemoconcentrationHemoconcentration
 Elevated LDH, amylase, AST, and CPKElevated LDH, amylase, AST, and CPK
 Elevated K and Phos are late signsElevated K and Phos are late signs

11. RadiologyRadiology
 Plain films – thumbprinting, thickenedPlain films – thumbprinting, thickened
bowel (<40% sensitivity)bowel (<40% sensitivity)
 CT – thickened/dilated bowel, intramuralCT – thickened/dilated bowel, intramural
hematoma, pneumatosis (64% sensitivity)hematoma, pneumatosis (64% sensitivity)
 MRI – promising but untested to dateMRI – promising but untested to date
 Mesenteric angiography – test of choice;Mesenteric angiography – test of choice;
can identify the type of AMIcan identify the type of AMI

12. Differential DiagnosisDifferential Diagnosis
Other serious conditions to consider:Other serious conditions to consider:
 PancreatitisPancreatitis
 Acute DiverticulitisAcute Diverticulitis
 Acute CholecystitisAcute Cholecystitis
 Small bowel obstructionSmall bowel obstruction
 Perforation of a viscousPerforation of a viscous
 Ruptured aneurysmRuptured aneurysm

13. TreatmentTreatment
 Resuscitation with fluids/blood productsResuscitation with fluids/blood products
 AnticoagulationAnticoagulation
 Infusion of a vasodilatorInfusion of a vasodilator
 Glucagon systemically ORGlucagon systemically OR
 Papaverine through a catheterPapaverine through a catheter

14. From Ischemia to InfarctionFrom Ischemia to Infarction
 Marked by peritoneal signs, feverMarked by peritoneal signs, fever
 Emergent laporatomyEmergent laporatomy
 Restoration of interrupted blood flow withRestoration of interrupted blood flow with
arteriotomy or bypass graftarteriotomy or bypass graft
 Resection of infarcted bowelResection of infarcted bowel
 Second-look in 24-48 hoursSecond-look in 24-48 hours
 Vasodilators and careful pressor useVasodilators and careful pressor use

15. A Word on Ischemic ColitisA Word on Ischemic Colitis
 Presentation: less & more focal painPresentation: less & more focal pain
(usually left-sided), more bloody diarrhea,(usually left-sided), more bloody diarrhea,
>90% are over 60 years old.>90% are over 60 years old.
 Etiology rarely identified: ?small vesselEtiology rarely identified: ?small vessel
disease +/- hypoperfusiondisease +/- hypoperfusion
 Episodes usually self limited except whenEpisodes usually self limited except when
stricture or gangrene developsstricture or gangrene develops
 Colonoscopy is initial evaluation of choiceColonoscopy is initial evaluation of choice