Ruptured Mycotic Abdominal Aortic Aneurysm Caused by Capnocytophaga ochracea after EVAR

We report a case of abdominal aortic aneurysm rupture after endovascular aortic repair (EVAR) caused by Capnocytophaga ochracea (C. ochracea). The case involved a 77-year-old man who underwent EVAR for an abdominal aortic aneurysm just below the renal artery 4 years earlier. The patient had been treated with antibiotics by his local doctor for fever of unknown origin and high C-reactive protein level, but his condition did not improve and he was referred to our clinic. Although the patient was hemodynamically stable and presented no symptoms other than fever, computed tomography-aortography showed a rapid expansion of the thrombosed abdominal aortic aneurysm, fluid retention outside the aneurysm, and destruction of the infected wall. Therefore, the patient immediately underwent emergency laparotomy. Intraoperative findings showed a large accumulation of pus within the aneurysm and a 4-cm rupture in the left posterior side of the aneurysm, as well as pus accumulation in the left retroperitoneum in the same area. Suspecting the presence of complicated stent graft infection, we removed all stent grafts. After removing the infected aneurysmal wall and careful debridement, we performed a Y-shaped vascular replacement and omental wrapping procedure. C. ochracea was detected in the wall of the infected aneurysm, and the patient was treated with antibiotics for 6 weeks after the surgery. The infection did not progress and the patient was discharged on day 49 after the surgery. C. ochracea should be kept in mind as a potential inflammatory organism in such cases because it can cause stent-graft and aneurysmal infections after EVAR.