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Aric Patel MS4 (UNECOM)  Ashley Davidoff MD (October 2023)

  • Acute gastrointestinal (GI) bleeds can occur from multiple causes, such as GI ulcers, diverticulosis, malignancy, angiodysplasia, trauma, and others. GI bleeds are separated into upper and lower bleeds based on their location relative to the ligament of Treitz, with upper bleeds proximal and lower bleeds distal to the ligament.  
    • Indications 
    • Failed endoscopic intervention 
    • Failed medical management 
    • Poor response to hemodynamic resuscitation 
    • Hemodynamic compromise 
    • Unable to perform endoscopic intervention due to poor visualization 
    • Inability to undergo endoscopic procedure due to medical or anatomic reasons 
    • Ongoing bleeding based on tagged RBC scan, CT, or angiography 

     

    • Contraindications 
    • There are no absolute contraindications as angiography and embolization may be necessary as lifesaving procedures. 
    • Relative contraindications include: 
    • Life-threatening contrast reaction, which can be mitigated by steroid preparation or premedication if contrast is necessary to stop critical bleeding 
    • Contrast related: 
    • Renal insufficiency 
    • Mild to moderate contrast allergy 
    • Uncorrectable coagulopathy 
    • In cases of high rate of bleeding, surgery may be preferred as angiography and embolization may not rapidly control the bleeding 
    • Advantages 
    • Transcatheter arterial embolization (TAE) is a safe and effective method of controlling acute GI bleeds. 
    • Less invasive compared to surgery 
    • Minimal blood loss 
    • Faster recovery times 
    • Disadvantages 
    • Requires correctly positioned catheters to reduce nontarget embolization, which may be challenging due to variant anatomy, poor visualization, and vessel spasm. 
    • Embolization carries the risk of bowel ischemia or infarction, require surgical intervention and resection 
    • Aim 
    • To embolize the bleeding vessels, reducing arterial perfusion pressure and promoting clotting 
    • Method 
    • Patient Preparation 
    • Consent 
    • Comprehensive history and physical exam 
    • Labs 
    • Complete blood count (CBC) and coagulation panel 
    • Hemodynamic resuscitation with appropriate fluids and blood products 
    • Adequate procedural monitoring 
    • The use of general anesthesia is preferred but the procedure can be done with moderate sedation 
    • Equipment Needed 
    • Lidocaine (with 25 gauge needle) 
    • Ultrasound 
    • Fluoroscopy 
    • Contrast agent 
    • Micropuncture Set 
    • 21G Micropuncture needle 
    • 0.018 guidewire (access wire) 
    • 5 French dilator and sheath 
    • 0.035 wire 
    • 5 French vascular sheath 
    • 5 French catheter 
    • 3 French microcatheter 
    • 0.018 microwire 
    • Torque (to allow better maneuverability of the microwire) 
    • Embolic agent: This will depend on the experience and preference of the operator  
    • Glue 
    • Gelfoam 
    • Coils 
    • PVA particles 
    • Vascular plugs 
    • Vasopressin (used to constrict mesenteric vessels to reduce perfusion pressure and allow clotting but rarely used anymore) 
    • Arterial closure device 
    • Technique (Steps) 
    • Access 
    • Using ultrasound find the femoral artery and mark the skin 
    • Confirm proposed vessel entry location is appropriate under fluoroscopy 
    • Make a skin wheel at the entry site and inject lidocaine around the vessel, as well as in the tract as you retract the lidocaine needle 
    • Under ultrasound guidance advance the micropuncture needle so it is touching the femoral artery 
    • Tent (poke the artery wall without piercing it) the needle on the vessel wall to confirm its location 
    • Advance the tip of the needle through the vessel wall to about the center of the vessel 
    • Confirm entry under ultrasound and with the return of brisk arterial blood 
    • Advance the access wire (part of the micropuncture kit) through the needle 
    • Check under fluoroscopy that the wire is in the correct location 
    • Remove the inner dilator and access wire and exchange it for a 0.035 wire 
    • Replace the outer micropuncture sheath for the 5 French vascular sheath over the 0.035 wire 
    • Attach a saline drip to the sheath to keep the access point patent (optional heparinized saline) 
    • Femoral artery access video: https://www.youtube.com/watch?v=S7UWo_MsWjc 
    • This procedure can also be done via the radial artery approach. To learn more (Link) 
    • Radial artery access video: https://www.youtube.com/watch?v=zQCx7wQSe-Q 
    • Angiography 
    • Catheters come in various shapes and sizes. The Interventional radiologist will select an appropriate length catheter with a specific shape that will allow them to access the vessel of interest 
    • Guide the wire and catheter through the arterial system to about T12 and inject contrast to identify the celiac trunk and superior mesenteric artery 
    • Select the vessel suspected as the source of the bleeding 
    • Perform a diagnostic angiogram to identify the bleeding vessel 
    • Usually, a digital subtraction angiography (DSA). DSA provides better visualization of the vessels 
    • If extravasation is not seen on injection of the main trunks, more subselective injection may be needed 
    • A microcatheter system is preferred to select smaller vessels 
    • Remove the wire while ensuring the catheter remains in place 
    • Insert a microcatheter and microwire through the 5 French catheter  
    • Advance the microcatheter system to select the bleeding vessel 
    • Perform another angiogram to confirm the selection of the bleeding vessel and identify any reflux of contrast 
    • The goal is to limit reflux of contrast to ensure little to no nontarget embolization 
    • Embolization 
    • Once the bleeding vessel has been selected and reflux is minimized with appropriate catheter placement 
    • It is time to embolize the vessel 
    • As mentioned above the specific embolic agent used will be based on the properties of the agent, experience, and preference of the primary operator 
    • One technique that can be attempted before embolization is to infuse vasopressin to stop the bleeding 
    • However, this technique will require a repeat angiogram in 15-30 minutes to ensure that bleeding has stopped 
    • Due to the limited success and longer procedure time, vasopressin is not an ideal agent in an emergency  
    • Once the embolic agent is deployed or injected. A repeat angiogram is needed to confirm that there is no flow distal to the embolization site and therefore no more active extravasation 
    • Coil embolization video: https://www.youtube.com/watch?v=99QsI0ITqrY 
    • Expected Results 
    • No evidence of bleeding on the final angiogram 
    • Potential Complications 
    • Common complications to all angiograms include: 
    • Puncture site bleeding, hematoma, and vessel dissection 
    • Contrast reactions 
    • Vasopressin complication 
    • Cardiovascular complications including MI, arrhythmia, and hypertension 
    • Embolization complication 
    • Nontarget embolization  
    • Bowel ischemia or infarction 
    • Discussion 
    • Although many cases of acute GI bleeds resolve spontaneously or are successfully managed by medical or endoscopic treatment. Refractory bleeds may require intervention by the IR team. Endovascular angiography and transcatheter arterial embolization have become critical components of the modern management of GI bleeding. Bleeds can be rapidly identified and stabilized with various embolic agents. With advancements in imaging and novel embolic agents, TAE is a minimally invasive and effective alternative to surgery.