Characterization and Management of Type II and Complex Endoleaks after Fenestrated/Branched Endovascular Aneurysm Repair

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Introduction: Endoleaks are more common after fenestrated/branched endovascular aneurysm repair (F/B-EVAR) than infrarenal EVAR secondary to the length of aortic coverage and number of component junctions. While reports have focused on type I and III endoleaks, less is known regarding type II endoleaks following F/B-EVAR. We hypothesized that type II endoleaks are common, and often complex (associated with additional endoleak types), given the potential for multiple inflow and outflow sources. We sought to describe the incidence and complexity of type II endoleaks after F/B-EVAR.

Methods: F/B-EVAR data prospectively collected at a single institution in an investigational device exemption clinical trial (G130210) were retrospectively analyzed (2014-2021). Endoleaks were characterized by type, time to detection, and management. Primary endoleaks were defined as those present on completion imaging or at first postoperative imaging; secondary were those on subsequent imaging. Recurrent endoleaks were those that developed after a successfully resolved endoleak. Reinterventions were considered for type I or III endoleaks, or any endoleak associated with sac growth >5mm. Technical success, defined as absence of flow in the aneurysm sac at procedure conclusion as well as methods of intervention were captured.

Results: Among 335 consecutive F/B-EVARs (mean±SD follow-up 2.5±1.5 years), 125 patients (37%) experienced 166 endoleaks (81 primary, 72 secondary, 13 recurrent). Of these 125 patients, 50 (40% of patients) underwent 71 interventions for 60 endoleaks. Type II endoleaks were the most frequent (n=100, 60%), with 20 identified during the index procedure, 12 (60%) of which resolved prior to 30-day follow-up. Of the 100 type II endoleaks, 20 (20%; 12 primary, 5 secondary, 3 recurrent) were associated with sac growth; 15 (75%) of those with associated sac growth underwent intervention. At intervention, 6 (40%) were reclassified as complex, with concomitant type I or type III endoleak. Initial technical success for endoleak treatment was 96% (68 of 71). There were 13 recurrences, all of which were associated with complex endoleaks.

Conclusions: Nearly half of the patients who underwent F/B-EVAR experienced an endoleak. The majority were classified as type II, with nearly a fifth associated with sac expansion. Interventions for type II endoleak frequently led to reclassification as complex, with a concomitant type I or III endoleak not appreciated on CTA and/or duplex. Further study is needed to determine if the primary treatment goal for complex aneurysm repair is sac stability or sac regression, as this would inform both the importance of properly classifying endoleaks noninvasively and the intervention threshold for managing type II endoleaks.

Keywords: NESVS 2022 Annual Meeting; endoleak; fenestrated branched endovascular aneurysm repair; thoracoabdominal aneurysm; type II endoleak.