Endovascular aneurysm repair (EVAR) has established as a minimally invasive methods to treat Abdominal Aortic Aneurysms (AAAs). Despite the great advantages of this technique, Endoleaks remains a big issue. Type III endoleak (TIIIEL) were caused by disconnections of modular graft components (IIIa) or defect in the fabric (IIIb) (Figure 1). Since the relative rarity of these events literature about are lacking and they were described mainly in case reports or small series dealing with few types or generation of endografts. The incidence reported in the multicenter registries about EVAR varies from 3% to 4.5% but mixed-up different type of endograft and device generation. At the best of the Authors knowledge the only report specifically addressed to this complication analyzed patients implanted with five types of endograft between 1995 to 2014 leaving a knowledge gap about the newer endoprosthesis. The aim of this article is to analyze the real-world incidence, possible etiology, treatment option and outcomes of TIIIELs in a third level Italian center

Observational, retrospective, single-center study enrolling patients with a diagnosis of TIIIEL after EVAR for AAA. After the initial EVAR, our follow-up protocol until 2009 consisted in CTA and clinical evaluation at 3 months, 6 months and yearly thereafter. From 2010 the previous protocol was modified as follow: CTA within 3-months and at 2-years from the index procedure and duplex-ultra-sound (DUS) examination at 1 month, 6-months and yearly thereafter. The endografts inserted during the initial EVAR procedure were classified in generations and grouped in periods (table I). Every TIIIEl identified was intended to treat. The decision-making process about interventional technique was carried out collegially. After the correction if it was carried out in endovascular fashion the patients were followed like described above; if a conversion to open repair was performed our follow-up scheduled DUS at 6 and 12 post-operative months and yearly thereafter. The primary outcomes were cumulative incidence of TIIIEL, time interval between initial EVAR and diagnosis of TIIIEL and impact of these complication on survival. Secondary outcomes included the relationship between endograft generation and type and incidence of type TIIIEL, as well as influence of implantation period.

Between 1994 to 2020 2665 EVAR were performed to correct AAA. A total of 95 (3.6%) TIIIEL (67IIIA, 28IIIB) were diagnosed over years. Different incidence for generation and periods was depicted in Table I. The mean time interval between the EVAR procedure and TIIIEL diagnosis was 54± 29 months. A total of 114 interventions were carried out to menage TIIIELs in 90 patients, 79 for TIIIaEL and 38 for TIIIbEL. 13 (13.6%) patients were treated with open repair, 11 with a complete conversion, 2 with a semi-conversion, 1 with stiches directly on the graft fabric. The remaining cases were menaced in an endovascular fashion. Only 5 TIIIELs were not corrected because for patient's refusal. The technical success of corrections was 97.8% (88/90) both for endovascular and open surgical interventions. Causes of failure were two intraoperative deaths during a conversion to open repair for anterior aneurysm rupture caused by a TIIIaEL and a TIIIbEL. In 15 patients treated endovascularly and in 2 with open surgery periprocedural adverse events occurred (table II). The overall mean follow-up after TIIIEl treatment was 99.8±62.8 months, After the successful correction of TIIIEL 15.9% (14/88) of the subject were treated again to correct a second TIIIEL. In patient's treated with I-II generation endografts, III generation and more recent generations generations the mean follow-up was 156.4±81, 106.1±49 and 66.0±27.0 moths respectively. Freedom from any aortic related re-interventions after TIIIEL correction was 92.9±3.9, 83.6±7.3%, 55.0±10.4 and 50.4±10.8 at 3-months, 1 year, 5 year and 10 years respectively. A total of 46 reinterventions were registered: 19 to manage a newly formed TIIIEl and 27 to address other device related complications.

TIII are a relatively rare but serious complication after EVAR. Most of them were misdiagnosed or found after the discovered of another type of EL and can occur at any time after the initial procedure. They were caused mostly by disconnections and are less frequent nowadays with current endograft generations. Most of them were successfully managed in endovascular fashion, but re-interventions were frequent.

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