Enteric Anastomotic Bleeding

Enteric anastomotic bleeding is hemorrhage from the suture or staple line of an intestinal anastomosis, into the lumen. It occurs in 1 to 4% of stapled gastrointestinal anastomoses, and less often with hand-sewn anastomoses. Most bleeding occurs within the first 48 hours after operation, and delayed bleeding can occur at 1 to 2 weeks when ischemia or a small leak erodes a vessel.

Sites: gastrojejunal after gastric bypass (about 1 to 4%), colorectal, small bowel, esophagojejunal and pouch anastomoses.

Risk factors

• Anticoagulant or antiplatelet therapy, thrombocytopenia, coagulopathy, renal failure and liver disease
• Technical factors (staple height too small for tissue thickness, firing across a mesenteric vessel, tension)
• Perioperative hypertension, large tissue bulk and inflammatory disease

The bleeding is self-limiting in over 85% of cases. Presentations are melena, hematochezia, hematemesis (upper anastomoses), a fall in hemoglobin and, in significant hemorrhage, hemodynamic instability. Complications: hypovolemic shock, anemia, anastomotic leak (rarely), intraluminal clot obstruction and the need for reoperation (under 5%).

• Melena, maroon stool or fresh blood per rectum, usually within 24 to 48 hours of surgery
• Hematemesis or nasogastric tube blood after upper anastomoses
• Tachycardia, hypotension, pallor, oliguria and dizziness
• A fall in hemoglobin of over 20 g/L, or a need for transfusion
• Red flags: hemodynamic instability, continued bleeding, abdominal distension, fever and signs of leak

1. Resuscitation and monitoring: vital signs, urine output, serial hemoglobin every 4 to 6 hours, coagulation studies, platelet count, creatinine, lactate and group and cross-match.
2. Endoscopy is the first diagnostic and therapeutic step in a stable patient: upper endoscopy for gastrojejunal and esophageal anastomoses, flexible sigmoidoscopy or colonoscopy with minimal insufflation (CO2) for colorectal anastomoses. Prior bowel preparation is not necessary for a low anastomosis.
3. CT angiography for brisk bleeding with a non-diagnostic endoscopy: contrast extravasation at the anastomosis (needs a bleeding rate over 0.5 mL/min).
4. Evaluate for leak with CT if fever, tachycardia or pain develop.

Differentials: stress ulcer, marginal ulcer, bleeding from the original disease (cancer, Crohn disease), diverticular bleeding, hemorrhoids, coagulopathy, and anticoagulant effect.

1. Resuscitation: two large-bore IV cannulae, IV crystalloid 20 mL/kg initially, then red cells when hemoglobin falls below 70 g/L (below 80 g/L with cardiovascular disease). Correct coagulopathy and give platelets if the count is under 50 × 10^9/L.
2. Stop and reverse anticoagulation when possible:
   • Warfarin: phytomenadione 5 to 10 mg IV by slow infusion and four-factor prothrombin complex concentrate 25 to 50 units/kg IV once.
   • Heparin: protamine 1 mg for each 100 units given in the previous 2 to 3 hours (maximum 50 mg), IV slowly.
   • Enoxaparin: protamine 1 mg for each 1 mg of enoxaparin given in the last 8 hours.
   • Dabigatran: idarucizumab 5 g IV. Apixaban and rivaroxaban: prothrombin complex concentrate 50 units/kg IV.
   • Tranexamic acid is not recommended for gastrointestinal bleeding, because it does not reduce mortality and it raises the risk of thrombosis.
3. Acid suppression for upper anastomoses: omeprazole 80 mg IV once, then 40 mg IV every 12 hours for 72 hours, then 40 mg orally once daily for 8 weeks.
4. Endoscopic hemostasis: submucosal injection of epinephrine 1:10,000 (up to 10 mL in 1 to 2 mL aliquots around the site), combined with clips (through-the-scope or over-the-scope) or a hemostatic powder. Use low insufflation pressure to protect a fresh anastomosis.
5. Angiographic embolization for bleeding that endoscopy cannot control in a stable patient, with a success rate of about 80 to 90%.
6. Reoperation for persistent hemodynamic instability, failed endoscopic and radiological treatment, suspected leak or large clot obstruction, with revision of the anastomosis and hemostasis.
7. Restart anticoagulation once hemoglobin has been stable for 48 to 72 hours, with a bridging plan in patients with mechanical valves.
8. Prevention: correct staple height selection for tissue thickness, careful hemostasis along the staple line, and perioperative blood pressure control.

Follow-up with hemoglobin at 1 and 2 weeks and iron supplementation if anemic: ferrous sulfate 200 mg orally once daily for 3 months, or ferric carboxymaltose 1000 mg IV as a single dose. Counsel on reporting melena or dizziness.