BACKGROUNDChronic obstructive pulmonary disease (COPD) is a known risk factor for abdominal aortic aneurysm (AAA) growth and rupture. The impact of COPD on AAA sac behavior following endovascular aneurysm repair (EVAR) is poorly understood. This study aimed to determine the association between COPD and sac remodeling after EVAR.METHODSWe identified all EVAR patients (2010-2021) in the Society for Vascular Surgery-Vascular Quality Initiative database. COPD severity (none, medication-treated, oxygen (O2)-dependent) was the primary exposure variable. The primary end point was 1-year sac growth post-EVAR. Mixed effects linear and logistic regression were used to assess the effects of COPD severity on sac remodeling, controlling for covariates. Cox proportional hazards regression and competing risks regression identified predictors of mortality and reintervention.RESULTS30,686 patients met inclusion criteria. COPD was present in 24% of patients (no COPD, 75.8% [n = 23,260], medication-treated COPD, 19.7% [n = 6,057], O2-dependent COPD, 4.5% [n = 1,369]). O2-dependent COPD was associated with persistent sac growth (mean difference: +0.55 mm, 95% confidence interval [CI] [0.05-1.05], P = 0.03) following EVAR implantation; however, medication-treated COPD was not (mean difference: -0.06 mm, 95% CI [-0.32 to 0.19]; P = 0.64). O2-dependent COPD patients did not experience increased reintervention rates (hazard ratio [HR] 0.82, 95% CI [0.65-1.02], P = 0.07) but were identified to have significantly increased mortality (HR 1.8, 95% CI [1.52-2.22], P < 0.0001).CONCLUSIONO2-dependent COPD was significantly associated with increased sac growth after EVAR. O2-dependent COPD did not correlate with increased reintervention, likely due to the disproportionately elevated mortality rates in this group. These findings highlight that patients with O2-dependent COPD have limited life expectancy and potentially less favorable sac remodeling, and elective EVAR should thus be reserved for only those at greatest risk for AAA-related mortality.