Type III Endoleak Incidence and Outcomes in Endovascular Aortic Repair: Comparison of Anatomical and Proximal Fixation Devices

Purpose: To evaluate the influence of endograft fixation type on the incidence, treatment, and outcomes of type III endoleaks (TIIIELs). Materials and methods: Abdominal aortic aneurysms (AAAs) treated with bifurcated endografts between 1994 and 2020 were prospectively collected and reviewed. The endograft included were classified as “Anatomical Fixation” (AF) (Powerlink [Endologix] and AFX [Endologix]) or “Proximal Fixation” (PF). The primary outcome was the incidence of TIIIEL over time, stratified by fixation type. Secondary outcomes included between-group comparisons of baseline characteristics, intraoperative details during TIIIEL correction, and survival analysis after TIIIEL diagnosis. Results: A total of 2065 endovascular aneurysm repairs were performed: 872 (42.2%) with AF and 1193 (57.8%) with PF devices. The estimated incidence of TIIIEL at 1, 5, and 10 years was 0.4%, 4.2%, and 7.3%, and 0.5%, 3.2%, and 4.6% for AF and PF, respectively (p=0.157), and fixation type was not associated with TIIIEL development in the competing risk regression model (p=0.101). The cumulative overall survival rate in patients diagnosed with TIIIEL did not differ significantly between the groups (p=0.077). The rate of recurrent TIIIELs was significantly lower in the AF group (7.1% vs 22.7%; p=0.044); however, no significant difference was found in secondary reintervention between the two groups (11.9% vs 27.3%, p=0.074). Patients with angulated and calcified aortic neck (SHR 3.4, 95% CI 1.2–9.6, p=0.022) and larger aneurysms (SHR 1.2; 95% CI 1.1–1.3; p<0.001) had a higher risk of TIIIEL. Likewise, the use of three or more endograft components increased the risk of TIIIEL by 3.1 times (SHR 3.1; 95% CI 1.7–5.4; p<0.001). Conclusions: The occurrence of TIIIELs was not affected by the type of endograft fixation. For larger abdominal aortic aneurysms (AAAs) and aneurysms with angulated and calcified aortic necks, there is a higher likelihood of developing TIIIELs during follow-up, regardless of the endograft type used. Clinical Impact: The type of fixation does not influence the incidence of TIII ELs. EVAR in larger AAAs and aneurysms with angulated and calcified aortic necks have a higher risk of developing TIII EL. Moreover, the risk of TIII EL is considerably increased by the use of three or more modular components.