Angiography in GI Bleeding

1. Indications
   1. Identification of Lower Gastrointestinal Bleeding site
   2. Preoperative evaluation for occult GI Bleeding source
   3. Criteria may include
      1. Early positive Tagged Red Cell Scan
      2. Frequent Blood Transfusion required
      3. Hemodynamic compromise
2. Mechanism
   1. Contrast dye infused via superior Mesenteric Artery and inferior Mesenteric Artery
   2. Extravasation of blood appears as a contrast blush on imaging
3. Efficacy
   1. Test Sensitivity: 40-78% for Lower Gastrointestinal Bleeding source
   2. Not as sensitive for slower active bleeding as tagged scan
      1. Identifies bleeding only if >0.5 ml/min
      2. Tagged cell scan used to preselect for angiography
   3. May identify non-bleeding lesion
      1. Tumors
      2. Angiodysplasia
   4. Best localizes bleeding (tagged cell scan inaccurate)
4. Management: Modalities to control bleeding
   1. Intra-arterial vasopressin infusion
      1. Risk of Myocardial Ischemia and arrhythmias
      2. Rebleeding rate: 50%
   2. Transcatheter embolization
      1. Risk of Intestinal Ischemia (<20%)
      2. Controls hemorrhage in 76-100% of patients
5. Complications (Complication rate 2-4%)
   1. Acute Renal Failure (Acute Tubular Necrosis)
      1. See Intravenous Contrast Related Acute Renal Failure
   2. IV Contrast reaction
   3. Thromboembolism
   4. Transient Ischemic Attack
   5. Insertion site hematoma
   6. Femoral artery thrombosis
6. References
   1. DeBarros (2002) Dis Colon Rectum 45(6): 802-8
   2. Wilkins (2009) Am Fam Physician 80(9): 977-83