Objective: The safety and feasibility of fenestrated/branched endovascular repair of acute visceral aortic disease in high-risk patients is unknown. The purpose of this report is to describe our experience with surgeon-modified endovascular aneurysm repair (sm-EVAR) for the urgent or emergent treatment of pathology involving the branched segment of the aorta in patients deemed to have prohibitively high medical and/or anatomic risk for open repair. Methods: A retrospective review was performed on all patients treated with sm-EVAR for acute indications. Planning was based on three-dimensional computed tomographic angiogram reconstructions and graft configurations included various combinations of branch, fenestration, or scallop modifications. Results: Sixteen patients (mean age [± standard deviation], 68 ±10 years; 88% male) deemed high risk for open repair underwent urgent or emergent repair using sm-EVAR. Indications included degenerative suprarenal or thoracoabdominal aneurysm (six), presumed or known mycotic aneurysm (four), anastomotic pseudoaneurysm (three), false lumen rupture of type B dissection (two), and penetrating aortic ulceration (one). Nine (56%) had previous aortic surgery and all patients were either American Society of Anesthesiologists class IV (n = 9) or IV-E (n = 7). A total of 40 visceral vessels (celiac, 10; superior mesenteric artery, 10; right renal artery, 10; left renal artery, 10) were revascularized with a combination of fenestrations (33), directional graft branches (six), and graft scallops (one). Technical success was 94% (n = 15/16), with one open conversion. Median contrast use was 126 mL (range, 41-245) and fluoroscopy time was 70 minutes (range, 18-200). Endoleaks were identified intraoperatively in four patients (type II, n = 3; type IV, n = 1), but none have required remediation. Mean length of stay was 12 ± 15 days (median, 5.5; range, 3-59). Single complications occurred in five (31%) patients as follows: brachial sheath hematoma (one), stroke (one), ileus (one), respiratory failure (one), and renal failure (one). An additional patient experienced multiple complications including spinal cord ischemia (one) and multiorgan failure resulting in death (n = 1; in-hospital mortality, 6.3%). The majority of patients were discharged to home (63%; n = 10) or short-term rehabilitation units (25%; n = 4), while one patient required admission to a long-term acute care setting. There were no reinterventions at a median follow-up of 6.2 (range, 1-16.1) months. Postoperative computed tomographic angiogram was available for all patients and demonstrated 100% branch vessel patency, with one type III endoleak pending intervention. There were two late deaths at 1.4 and 13.4 months due to nonaortic-related pathology. Conclusions: Urgent or emergent treatment of acute pathology involving the visceral aortic segment with fenestrated/branched endograft repair is feasible and safe in selected high-risk patients; however, the durability of these repairs is yet to be determined. © 2013 by the Society for Vascular Surgery.