Natural history of isolated type II endoleaks in patients treated by fenestrated-branched endovascular repair for pararenal and thoracoabdominal aortic aneurysms

Objective: Type II endoleaks (T2ELs) are common after endovascular aneurysm repair (EVAR), but little is known about their natural history in patients treated by fenestrated-branched EVAR (F/BEVAR). We sought to evaluate the natural history of isolated T2EL after F/BEVAR for pararenal aortic aneurysms (PRAs) and thoracoabdominal aortic aneurysms (TAAAs). Methods: Consecutive patients enrolled in a prospective nonrandomized study to investigate F/BEVAR for PRAs and TAAAs at a single institution (2014-2017) were identified. Computed tomography angiography images at discharge and during follow-up were reviewed. Patients with ≥12 months of follow-up were included and divided in two groups for comparison based on the presence or absence of T2ELs. Patients with any non-T2ELs were excluded. Multivariable logistic regression was used to assess factors associated with T2EL occurrence. Primary outcomes were absolute and relative sac diameter change and sac diameter increase >5 mm. Secondary outcomes included overall survival, aorta-related death, reinterventions, and conversion or rupture. Results: There were 184 patients (136 male [74%]) with PRAs (n = 70 [38%]) and TAAAs (n = 114 [62%]) with an average age of 74 ± 7 years included. Isolated T2ELs were seen in 76 patients (41%); of these, 71 T2ELs (93%) were primary. Patients with T2ELs were more likely to have larger aneurysms (mean baseline diameter, 66 ± 8 mm vs 63 ± 8 mm; P =.01), patent inferior mesenteric artery (66% vs 32%; P <.001), and more lumbar arteries (mean, 6 ± 1 vs 4 ± 1; P <.001). In the multivariable analysis, these were all independently associated with T2EL occurrence. Of all T2ELs, only 18 (24%) resolved spontaneously during a mean follow-up of 31 ± 15 months. Mean absolute sac diameter reduction for patients without T2ELs and with T2ELs, at 12 and 36 months, was 10.2 ± 5.9 mm vs 2.6 ± 6.4 mm and 16.3 ± 7.3 mm vs 5.7 ± 11.3 mm, respectively (P <.001). For the same groups, the mean percentage sac diameter reduction at 12 and 36 months was 16.4% ± 9.4% vs 3.8% ± 9.8% and 26.4% ± 11.6% vs 8.8% ± 17.7%, respectively (P <.001). Overall, 13 patients showed sac increase >5 mm, and all these instances were recorded in the T2EL group; 8 required reintervention. T2ELs were not associated with decreased overall survival, freedom from aorta-related death, or freedom from any reintervention. Conclusions: Isolated T2ELs are common after F/BEVAR for PRAs and TAAAs, usually seen early; they are most often associated with inferior mesenteric or lumbar artery flow and tend to persist in follow-up. Their presence is associated with impaired sac shrinkage and risk of sac growth with subsequent need for secondary interventions. Although not associated with decreased overall survival or loss of freedom from aorta-related death, T2ELs require serial imaging surveillance.