Late type II endoleaks after endovascular aneurysm repair require intervention more frequently than early type II endoleaks

Objective: Type II endoleaks (T2ELs) are commonly observed after endovascular aneurysm repair (EVAR). We sought to determine whether time at onset of T2ELs correlated with the need to intervene based on sac expansion or rupture. Methods: Between 1998 and 2015, 462 EVARs performed at our institution had duplex ultrasound surveillance in our accredited noninvasive vascular laboratory. Computed tomography and arteriography were reserved for abnormal duplex ultrasound findings. The need for intervention for T2ELs was classified according to time at onset after EVAR. Interventions for T2ELs were performed only for sac expansion >5 mm or rupture. We defined early-onset T2ELs as <1 year after EVAR and delayed or late onset as >1 year of follow-up. Results: Of the 462 EVARs, 96 patients (21%) developed T2ELs after implantation. Of these, 65 (68%) had early and 31 (32%) had late onset (mean, 12 months; range, 1-112 months). Early T2ELs resolved without treatment in 75% (49/65) of cases compared with only 29% (9/31) of late T2ELs (P <.0001). Intervention was required for only 8% (5/65) of patients with early T2ELs (5 sac expansions, 0 ruptures) compared with 55% (17/31) for late T2ELs (16 sac expansions, 1 rupture; P <.0001). The remaining patients were observed for persistent T2ELs with no sac growth (17% [11/65] early vs 16% [5/31] late; P =.922). Conclusions: Less than one-third (29%) of T2ELs that develop after 1 year will resolve spontaneously and about half (55%) will require intervention for sac growth or rupture. T2ELs that develop >1 year after EVAR should be followed up with a more frequent surveillance protocol and perhaps with a lower threshold to intervene.