Gastrointestinal: A rare case of gastrointestinal bleeding caused by arterio‐enteric fistula

One day ago, a 61-year-old woman presented with five episodes of hematochezia without an obvious cause. The hematochezia was dark red and mixed with stool. She had high fever, with a body temperature of ~102°F. She had been diagnosed with endometrial cancer 2 months ago, for which she underwent hysterectomy, bilateral adnexectomy, and lymph node dissection. Her heart rate was 133 beats/min, and blood pressure was 109/81 mmHg. Laboratory data showed hemoglobin as 98 g/L, leukocyte count as 12.9 × 109/L, and platelet count as 202 × 109/L. An increase in fibrinogen (4.6 g/L) and d-dimer levels (6.4 g/L) was noted. As shown in Figure 1a, contrast-enhanced computed tomography (CT) of the whole abdomen revealed a mixed-density shadow with gas formation in the right pelvic cavity and poor continuity of the blood wall of the right external iliac artery. Twelve hours later, the patient passed bloody stools again (2000 mL) and reported feeling dizzy and fatigued. After initial resuscitation and stabilization of vital parameters, angiography was performed, which revealed (Fig. 1b) the leakage of contrast material from the right external iliac artery into the surrounding region. Considering the possibility of further bleeding which could worsen her condition, she subsequently underwent an exploratory laparotomy. During the exploratory laparotomy, a rupture of the right external iliac artery was identified, which was closely attached to the small intestine, forming a deep blind fistula surrounded by blood clots and necrotic tissue. Right external iliac artery ligation and intestinal perforation repair were performed. Femoro-femoral bypass (FF bypass) was subsequently performed for vascular reconstruction. The patient recovered well after surgery and was followed up for 1 year; CT performed at 1-year follow-up showed (Fig. 2a) that unlike the preoperative findings, the right external iliac artery was absent locally and the mixed-density shadow and gas in the right pelvic cavity had disappeared. Three-dimensional CT confirmed that (Fig. 2b) there was no perfusion of the right iliac artery and that there was good flow to the right femoral artery through the FF bypass. AEF is a rare but potentially fatal connection between the artery and gastrointestinal tract. This condition typically manifests as unexplained gastrointestinal bleeding and unexplained fever, with even massive hematochezia and death noted in severe cases. CT with a contrast medium is the most appropriate diagnostic test. However, exploratory laparotomy is often required to confirm diagnosis. There are two forms of the disease: primary disease occurring from trauma, radiation, tumor invasion, or penetrating ulceration and secondary disease associated with prior non-vascular abdominal or pelvic surgical intervention. In the present case, the cause was believed to be the damage caused to the right external iliac artery during radical endometrial carcinoma surgery 2 months ago, followed by adhesion and fistula formation. There is a wide range of treatment modalities for AEF, but there is no consensus on the best management of the condition. Endovascular surgery is now considered to have better early survival than open surgery for secondary AEF, particularly in patients with significant bleeding. However, endovascular surgery is not always feasible or effective, and for patients with unstable conditions, an urgent switch to open surgery is required.