Mesenteric Artery Occlusion

Aka: Mesenteric Artery Occlusion, Superior Mesenteric Artery Occlusion, Acute Superior Mesenteric Artery Occlusion, Superior Mesenteric Artery Embolism, Superior Mesenteric Artery Thrombosis, Mesenteric Artery Embolism, Mesenteric Artery Thrombosis, Acute Mesenteric Arterial Occlusion, Superior Mesenteric Artery Stenosis, Celiac artery stenosis, Embolic Mesenteric Infarction

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II. Epidemiology

  1. Age over 60 years

III. Pathophysiology

  1. Mesenteric Artery Embolism (50% of Acute Mesenteric Ischemia)
    1. Superior Mesenteric Artery is affected in most cases
      1. More than half lodge distal to the middle colic artery origin (6-8 cm from SMA origin)
  2. Mesenteric Artery Thrombosis (15-25% of Acute Mesenteric Ischemia)
    1. Most often occurs at origin of major mesenteric vessel (Celiac Artery, SMA, IMA)
    2. Often at least two major vessels are occluded or stenosed
    3. Results in extensive bowel infarction

IV. Causes

  1. Mesenteric Artery Embolism, esp. superior Mesenteric Artery (50% of Acute Mesenteric Ischemia)
    1. Cardiac thrombus source is most common
      1. Mural thrombus (following Myocardial Infarction)
      2. Atrial thrombus
        1. Atrial Fibrillation
        2. Mitral Stenosis
      3. Septic embolus
        1. Valvular endocarditis
        2. Mycotic aneurysm
    2. Vascular Sources
      1. Aortic atheromatous Plaque
      2. Vascular aortic prosthetic graft
    3. Asoociated with other emboli (20%)
      1. Malignancy
      2. Coagulation Disorder
  2. Mesenteric Artery Thrombosis (15-25% of Acute Mesenteric Ischemia)
    1. Preexisting visceral atherosclerotic disease
      1. Typically associated with underlying Chronic Mesenteric Ischemia
    2. Other vascular conditions
      1. Aortic Dissection
      2. Mesenteric Artery rupture
      3. Fibromuscular Dysplasia
      4. Vasculitis (typically affects smaller vessels)
    3. Associated precipitating factors for acute thrombosis
      1. Abdominal Trauma
      2. Acute infection

V. Symptoms

  1. See Mesenteric Ischemia
  2. Vomiting
  3. Severe, colicky or cramping, poorly localized Abdominal Pain
    1. Pain is severe and abrupt, sudden onset and out of proportion to exam in mesenteric embolism
    2. Pain is gradual and less severe in mesenteric thrombosis (due to incomplete Occlusion, collaterals)
  4. Other symptoms
    1. Nausea and Vomiting
    2. Forceful bowel evacuation (Diarrhea progressing to Constipation)

VI. Diagnosis: Classic Triad on presentation

  1. Cardiac disease
  2. Acute Abdominal Pain
  3. Acute gastrointestinal emptying (Vomiting and forceful bowel evacuation)

VII. Labs

  1. Metabolic Acidosis
    1. Acute Abdominal Pain and Metabolic Acidosis is Acute Mesenteric Ischemia until definitively excluded

VIII. Imaging

  1. See Mesenteric Ischemia
  2. Angiography (gold standard)
  3. CT Abdomen Pelvis and CT Angiography
    1. First-line study in most cases
    2. Efficacy
      1. Test Sensitivity: 71-96%
      2. Test Specificity: 92-94%
    3. Progression of bowel changes in Mesenteric Ischemia
      1. Mesenteric Edema and streaking
      2. Bowel wall thickening (edema, Hemorrhage)
      3. Bowel wall gas (pneumotosis intestinalis) and Portal Vein gas in necrosis
    4. Findings in Mesenteric Occlusion
      1. Mesenteric Artery Thrombosis will demonstrate proximal stenosis or Occlusion of SMA, IMA or Celiac Artery
      2. Mesenteric Artery Embolism related Occlusion site is more difficult to identify on CT
  4. MRA Abdomen
    1. Similar findings to CT Angiogram
  5. Angiography (gold standard)
    1. Largely replaced by CT, but indicated in unclear cases (e.g. embolus)
    2. Also indicated for intervention
    3. Best defines Occlusion and stenosis sites
      1. Anteroposterior Views (collateral pathways)
      2. Lateral Views (visceral branches)
  6. Mesenteric Duplex Ultrasound
    1. Evaluates only proximal, main vessels (SMA, IMA and Celiac Artery)
    2. Test Sensitivity: 70-89%
    3. Test Specificity: 92-100%
  7. Abdominal XRay
    1. Listed for historical reasons only (all other advanced imaging is preferred)
    2. Normal initially
    3. Late findings
      1. Thumb printing
      2. Pneumatosis
      3. Portal venous gas

IX. Management

  1. See Mesenteric Ischemia
  2. Targeted Papaverine infusion via angiography
    1. Risk of Hypotension if catheter migrates into aorta
  3. Mesenteric Artery Embolism Reperfusion
    1. Catheter-Directed Local Thrombolysis within 8 hours of symptom onset
      1. Tenecteplase Infusion
      2. Reteplase Infusion
      3. Schoots (2005) J Vasc Interventional Rad 16:317-29 [PubMed]
      4. Yanar (2013) World J Energ Surg 8:8 +PMID: 23394456 [PubMed]
      5. Wang (2011) Abdom Imaging 36:390-8 [PubMed]
    2. Transverse Arteriotomy
      1. Palpable clot within vessel is extracted proximal to embolism with balloon-tipped Fogarty catheter
    3. Bypass Graft
  4. Mesenteric Artery Thrombosis
    1. Anticoagulation (Heparin transitioned to Warfarin, and continued for >=6 months)
    2. Revascularization (if bowel not gangrenous)
      1. Aortomesenteric bypass
      2. Trans-aortic endarterectomy

X. Prognosis

  1. Mortality: 70-90%

XI. Prevention

  1. Reduce Cardiovascular Risk Factors
  2. Refer Asymptomatic Superior Mesenteric Artery Stenosis to vascular surgery

XII. References

  1. Fraboni (2012) Board Review Express, San Jose
  2. Mastoraki (2021) World J Gastrointest Pathophysiol 7(1): 125-30 [PubMed]

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