Increasing disparity between Society for Vascular Surgery guidelines for infrarenal abdominal aortic aneurysm repair and real-world practice

Abstract

ObjectiveThe current Society for Vascular Surgery (SVS) guidelines, based on randomized controlled trials published more than a decade ago, recommend a minimum threshold diameter of 5.5 cm for infrarenal abdominal aortic aneurysm (iAAA) repair. It is unknown whether practice patterns with respect to size of repair have changed since the publication of these guidelines. We aimed to evaluate the real-world practice of vascular surgeons in our region with respect to iAAA size at the time of repair, whether this has changed over the past 12 years and if any changes were associated with the repair type, open vs endovascular. MethodsThe Vascular Study Group of New England (VSGNE) database was used to identify all patients who received iAAA repair between 2003 and 2015. The primary end point was to quantify the annual percentage of iAAAs repaired in different size categories (≥5.5 cm; <5.5 cm but ≥5.0 cm; <5.0 cm) over the study time period and by type of repair. The secondary end points were morbidity and mortality in these groups. We excluded nonelective cases (ruptured or symptomatic), patients with coexisting iliac artery aneurysms, and those missing critical data. ResultsA total of 5314 patients with iAAA repairs (1538 open, 3776 endovascular) were identified in the VSGNE database during the study period. In 40% (2110 of 5314) of patients, repair was performed for aneurysms <5.5 cm, with endovascular aneurysm repair (EVAR) comprising 75% (1581 of 2110) and open 25% (529 of 2110). More EVARs were performed for <5.5 cm in 2015 (46%) compared with 2003 (33%) (P < .05, n − 1 χ2) with an average increase of 1.1%/y. There was also a non-statistically significant increase in open repair of small aneurysms (0.7%/y; P = .759). Overall, 30-day mortality was 1.11% in the EVAR group (0.54% in <5.0 cm, 0.91% in ≥5.0 but <5.5 cm, and 1.55% in ≥5.5 cm), compared with 3% in the open group (2.88%, 1.79%, and 3.77%, respectively) with no significant change in mortality in either group over time. ConclusionsDespite the SVS guidelines suggesting surveillance rather than repair of iAAA <5.5 cm, an increasing proportion of repairs in the VSGNE database were performed below that threshold. The reasons for this are likely multifactorial and might include a lesser complexity and lower operative mortality for smaller aneurysms and markedly improved third- and fourth-generation stent graft technology with possibly better long-term survival. As such, it may be time to re-examine the current guidelines for iAAA repair.