Proximal Seal After Endovascular Aneurysm Repair: Why Sealing Length Dynamics and Type 2 Endoleak Matter

Aim: To determine whether achieved sealing length (SL) at the first postoperative computed tomography angiography (CTA) and its subsequent change over time are associated with later endoleak type 1A (EL1A) after infrarenal endovascular aortic repair. Secondary aims were to describe longitudinal remodeling of SL and to assess the association between persistent type 2 endoleak (EL2) and SL trajectories. Methods: This retrospective study analyzed SL and sealing surface measured on postoperative CTA, using the first postoperative CTA as the reference examination. We examined whether the first postoperative seal, its subsequent change over time, and prior persistent EL2 were associated with later EL1A. Trajectories of ΔSL and Δsealing surface were modeled using spline mixed-effects models. Time to EL1A was analyzed using Cox models with predictors at the first CTA and pre-event change, including a joint baseline-plus-change model. Landmark analyses were used to assess sealing behavior and EL1A risk. Type 2 endoleak was treated as a time-varying exposure, and its association with subsequent EL1A was evaluated using landmark Cox analyses at 12, 24, 36, and 60 months. Results: Among 501 patients, 346 were included in the longitudinal cohort; after a median follow-up time of 56 months (interquartile range, 28–95 months), 73 developed EL2, 39 developed EL1A, and 8 experienced both events. Baseline sealing at the first postoperative CTA and sealing deterioration were independently associated with EL1A in joint models (SL and sealing surface). Type 2 endoleak was associated with differential SL remodeling (interaction P < .001), with progressive divergence after ~24 months. In exploratory landmark analyses, EL2 was associated with higher subsequent EL1A hazard (36-month hazard ratio [HR] = 2.48; P = .030; 60-month HR = 3.14; P = .008), persisting after adjustment for sealing state and change up to the landmark. Conclusions: Both the first postoperative infrarenal seal and its variation during follow-up were associated with later EL1A. Persistent EL2 was associated with sealing deterioration, whereas its association with subsequent EL1A should be considered exploratory because few patients experienced both events. Clinical Impact In infrarenal endovascular aneurysm repair, both the sealing length achieved at the first postoperative computed tomography angiography and its longitudinal change were associated with later type 1A endoleak (EL1A). Persistent type 2 endoleak was associated with less favorable sealing evolution and may identify patients with reduced seal stability and exploratory higher subsequent EL1A risk.