Ischemic Colitis following Translumbar Thrombin Injection for Treatment of Endoleak

Endoleaks remain a significant challenge after endovascular abdominal aortic aneurysm repair (EVAR). Translumbar thrombin injection of the aneurysm sac has been used to treat endoleaks, with low reported morbidity. We present an unusual case of ischemic colitis following translumbar thrombin injection of an endoleak. A 67-year-old male with a 5.8-cm abdominal aortic aneurysm (AAA) was evaluated for endograft repair. The patient underwent preoperative embolization of the right hypogastric artery. The AAA was repaired using a unibody bifurcated graft (Ancure). Completion aortogram revealed no endoleak and a widely patent left hypogastric artery. Computed tomography (CT) at 2 months showed an endoleak appearing to originate from a lumbar artery near the proximal attachment site with outflow via the inferior mesenteric artery (IMA). The endoleak was successfully treated with CT-guided translumbar injection of 8000 units of thrombin into the aneurysm sac. The patient subsequently developed chronic abdominal pain, diarrhea, and a weight loss of 20 lbs. Colonoscopy revealed ischemic colitis of the rectosigmoid colon. Duplex evaluation indicated a patent superior mesenteric artery and IMA distal to its origin. Medical treatment failed and the patient underwent a low anterior resection 2 months later (4 months post-EVAR). Subsequently, the aneurysm has decreased to 5.4 cm, with no evidence of endoleak at 1 year. We conclude that ischemic colitis may occur following translumbar thrombin injection. Thrombin embolization into the rectosigmoid arcade via the IMA was most likely the cause in this case. This problem can potentially be avoided by treating the IMA endoleak outflow prior to translumbar thrombin injection of the aneurysm sac. Thorough arteriographic evaluation of endoleaks should be performed prior to any interventions.