Population-Based Outcomes Following Endovascular and Open Repair of Ruptured Abdominal Aortic Aneurysms

Hospital mortality rates for ruptured abdominal aortic aneurysms (rAAA) underestimate overall death rates since a considerable number of patients die of free rupture before presenting to a hospital.1 Among patients (See commentary page 565) presenting acutely to hospitals, mortality remains quite high despite rapid surgical intervention. For the past 4 decades, there seems to have been little progress in the outcomes of emergently repaired rAAAs, with inpatient mortality remaining at 40% and 60%.2 The gold standard for this repair has long been an open surgical approach. However, recently, the less invasive technique of stent-graft repair has been gaining favor with surgeons worldwide. Endovascular aneurysm repair (EVAR) for intact AAA was brought to worldwide notice by Parodi et al.3 in the early 1990s. The procedure, initially held to be best utilized for poor surgical candidates, has now achieved widespread use, reducing hospital and intensive care unit (ICU) stays, early complications, and early mortality.4–8 Randomized control trials have documented a reduction in perioperative mortality compared with conventional open repair.4–6 In follow-up over 1 to 4 years, other studies have shown that late survival is similar, however.5,8,9 The earliest endovascular repair for ruptured AAA (rEVAR), which was reported in 1994,10 demonstrated the feasibility of the procedure; 5 years later, Ohki et al.11 published a series of 12 patients. The growth of the rEVAR technique, however, has lagged far behind that of its non-emergent counterpart given the vast requirements for technical expertise, facility specialization in endovascular interventions, large inventory, device specifications, anatomical requirements, and the need for reasonable hemodynamic stability for appropriate preoperative imaging. Retrospective series revealed that there could be an advantage to rEVAR,12,13 with early mortality rates of 8% to 40%. Single-center prospective trials and one multicenter trial have shown a potential benefit for rEVAR14–21; however, due to small patient numbers, statistical significance has rarely been shown. Additionally, because of the technical requirements of the procedure, the impact of annual volume on outcomes of rAAA repairs is an important factor that cannot be assessed by single institutional series. It has been shown that there is a significant relationship between higher surgeon and hospital volume and improved patient outcomes after open surgical repair for rAAA.22,23 Holt et al.,24 however, found that there was no significant relationship between volume and outcome for rAAA repair in the UK. Existing data, which includes rEVAR as well as open repair, shows conflicting results and is limited by early experience, small numbers, and variation in the volume criteria used.24–26 To further expand on this work, the current study utilized the Nationwide Inpatient Sample (NIS) in order to analyze national outcomes for in-hospital mortality rates after repair of rAAAs and to assess the impact of procedural volume specifically in the setting of aneurysm rupture.