Characteristics and outcomes of small abdominal aortic aneurysm rupture in the ACS-NSQIP database.

Abstract Objectives The current guidelines recommend elective abdominal aortic aneurysm (AAA) repair at 5.5cm in men and 5.0cm in women. However, rupture can occur in patients with aneurysm below these size thresholds. This study aims to investigate the proportion of AAA that rupture below elective operative thresholds and compare the outcomes of repair to those of ruptured aneurysm at a larger size. Our hypothesis is that rupture of small AAA carries similar mortality as rupture at larger sizes. Methods ACS-NSQIP targeted vascular files for open AAA repair and endovascular aneurysm repair (EVAR) were reviewed for all cases of ruptured AAA (rAAA) between 2011-2018. Patients were divided into two groups: “small rAAA” for those presenting with ruptured aneurysms below current size guidelines and “large rAAA” for those that met size criteria for elective repair. Univariate analyses were conducted to compare comorbidities and perioperative outcomes of infrarenal rAAA repair between the groups. Multivariable logistic regression was performed to examine differences in mortality between small and large rAAA, when controlling for confounding variables. Results Of the 1,612 ruptured AAA repairs, 167 (10.4%) were small rAAAs. The proportion of small rAAA did not significantly change during the study period (p=0.15). Large rAAA patients were more likely to have juxta/suprarenal aneurysms compared to small rAAA patients (27% vs 16%, P=.001). Comparison of infrarenal rAAA only demonstrated that the mean small rAAA (n=141) diameter was 4.1 cm in females and 4.5cm in males compared to large rAAA (n=1051) mean diameter of 7.1cm in females and 8.3cm in males (p Conclusion Amongst all AAA repairs classified as being for rupture, 10% are in patients with small AAA. Patients with small AAA rupture are less likely to present with hypotension and more likely to be treated with EVAR. Further research into sac morphology and more sensitive imaging modalities may help identify small rAAA at high risk of rupture that would benefit from elective repair