Gastrointestinal bleeding can be catastrophic and life-threatening. Only 5% of them originate from the small bowel. To offer the correct treatment it is mandatory to find the bleeding site, which can be a challenge. In unstable patients, balloon endoscopy and video capsule are not valid, and these patients need one of two options: transarterial embolization or surgical resection of the bleeding site. Trying to find the exact location of bleeding, doctors can use preoperative angioCT, intraoperative enteroscopy (both bowel opening and sterilized endoscope are needed), or intraoperative angiography with dye injection. However, if the bleeding is from the small bowel and the patient is offered a resection surgery, intraoperative localization of the bleeding site is not an easy task. Missing the bleeding site will cause a recurrence, but an excessive resection can also cause absorption deficiencies.
All efforts are welcome to find an accurate technique to give the exact location of the bleeding site so that the surgeon can resect the less bowel possible. You may say an embolization can solve the problem, but according to Kawachi et al. transarterial embolization has 61-91% of clinical success. Additionally, bowel ischemia occurs in up to 10 % of patients following embolization. Indocyanine green (ICG) can be the answer the surgeons' need.
Jun Kawachi et al. from the Department of Surgery of Kamakura (Japan) reported 8 patients with massive bleeding from the small bowel who were treated with ICG guided small bowel resection. All patients were initially submitted to an abdominal CT scan, diagnosing dye extravasation in the small bowel. All patients were immediately transferred to a hybrid room for intraoperative angiography. A microcatheter was placed as close to the bleeding site as possible. Laparotomy was then performed, and 3-5 mL of ICG was injected through the microcatheter. The surgeon resected all the green-stained bowel.
Seven out of eight patients were submitted to a green-stained bowel resection during intraoperative angiography with IGC injection. The eighth patient had no findings during angiography and surgery was stopped. Pathology diagnosed the bleeding cause in 6 patients. The only patient with no findings in the resected bowel had a self-limited bleeding recurrence. The mean resected bowel length was 35,3 cm. Two patients had only 4 and 8 cm of bowel resected. I believe this is very important data since it was probably the use of ICG injection that made possible such a minor bowel resection. Is there any surgeon who had only resected 4 cm to treat massive bleeding?
We all know that the indication to manage massive bleeding is to perform angiography and eventually a transarterial embolization. If it fails, surgery comes next. The authors used the indication for angiography, but instead of embolization as the first option, they used resection surgery with ICG injection through a microcatheter. Was this a good option? I believe it was. First, this has the advantage of giving pathology results and bleeding cause. Secondly, coiling can fail, and in an unstable patient, this can be catastrophic and implicate an emergency transfer to the operation room. Using intraoperative ICG dye injection patient is already in the operation room. Third, there are no studies comparing embolization with surgery in small bowel bleeding.
There are several intraoperative angiographic marking methods. Mythelen blue dye injection through a microcatheter has become the preferred method. However, because of its association with DNA damage and the widespread of narrow-band imaging, its popularity is declining. On the contrary, indocyanine green (ICG) is safer and easily available. ICG has very low toxicity, has been used for preoperative evaluation of liver function before resection and for assessing organ perfusion during gastrointestinal surgery. Now, according to Jun Kawachi et al. “intraoperative angiography with ICG injection can be a feasible method for identifying the sites of massive small bowel bleeding, thereby enabling resection”.
Once again, I would like to highlight the small length of bowel that was resected in two patients (4 cm and 8 cm). This is a major advantage of intraoperative ICG injection to help surgeons' guide the small bowel resection. This technique can reduce both invasiveness and aggressiveness of surgery. With the use of fluorescence imaging, laparoscopy can make surgery even less invasive. As stated by the authors, the threshold for positive angiographic finds must be strict. In case of doubt, Kawachi advises the use of local anesthesia for angiography and moving towards general anesthesia if surgery is necessary. This is a great way to escalate the treatment algorithm.
There are three take-home messages. First, intraoperative ICG injection through a microcatheter placed as most distal as possible by angiography can be a very good option to treat unstable patients with small bowel bleeding. Secondly, small length resection is possible using ICG. Third, laparoscopic resection of the small bowel guided by ICG injection will bring the advantages of minimally invasive surgery to a life-saving emergency procedure. I believe the future is here.
Link to PubMed:
Dr. Carlos Eduardo Costa Almeida
General Surgeon
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