Riolan arch pseudoaneurysm hemorrhage after endovascular covered stent-graft treatment of an abdominal aortic aneurysm: A case report.

Introduction: Riolan arch thickening is usually caused by the occlusion of the superior mesenteric artery (SMA), inferior mesenteric artery, or abdominal aortic artery, by colon cancer, or by ulcerative colitis in the active phase. Patientconcerns: A 61-years-old female was admitted due to left lower abdominal pain, nausea, and vomiting for more than 4 days. She had received an endovascular covered stent-graft exclusion due to abdominal aortic aneurysm 18 months earlier. Computed tomographic angiography (CTA) showed a local rupture of 1 of the branch artery of the SMA, and a pseudoaneurysm was formed around it. It was feared that performing Riolan atrial arch pseudoaneurysm embolization may cause ischemia of the inferior mesenteric artery (IMA) and could lead to avascular necrosis of the descending colon and sigmoid colon, intestinal perforation, and peritonitis. Diagnosis: Riolan arch collateral circulation associated with pseudoaneurysm hemorrhage after endovascular covered stent-graft treatment of an abdominal aortic aneurysm. Interventions: Riolan arterial arch pseudoaneurysm embolization was performed near the distal end. Outcomes: The symptoms, signs, and biochemistry returned to normal. Conclusion: Riolan arch collateral circulation can be caused by pseudoaneurysm hemorrhage after endovascular covered stent-graft treatment of an abdominal aortic aneurysm.