Impact of Target Visceral Vessel Anatomical Configuration on Early Complications Following Endovascular Repair of Thoracoabdominal Aortic Aneurysms

Background: Fenestrated and branched endovascular aortic repair (fEVAR-bEVAR) is a viable treatment option for thoracoabdominal aortic aneurysms but target visceral stent (TVS) endoleak and thrombosis remain a limiting factor. This study aims to evaluate TVS anatomy impact on 1-year risk of thrombosis and endoleak. Methods: Patients treated with fEVAR-bEVAR for thoracoabdominal aneurysms between 2008 and 2020 in our centre were enrolled. We recorded comorbidities, operative details, 1-month postoperative CT scan (anatomical reference), and TVS behaviour: thrombosis and endoleak at 1-year follow-up. For each TVS, different points were identified using a centre-lumen-line: (A) TVS origin, (B) end of branch/fenestration, (C) visceral vessel entry, (D) end of TVS, (E) 1-cm distally. We analyzed TVS tortuosity ((centre-lumen-line/straight distance)-1, in %), image vector analysis of each segment in 2D (antero-poster ior, left-right) and 3D (craneo-caudal displacement), and centre-lumen-line analysis (bending in ABC and CDE). Three independent observers performed a blind analysis, and anatomical differences between bEVAR/fEVAR, and cases with/without 1-year thrombosis and TVS endoleak, were compared using Kaplan-Meier curves (Log-Rank test), and t-test/Wilcoxon signed-ranks test respectively. Results: Fifty-four patients (72 +/- 713 years mean age; 182 TVS: 50 branches, 132 fenestrations) met the inclusion criteria. bEVAR cases had longer stents, with more caudal 3D angulation, and greater ABC angulated segment. After excluding bEVAR cases (low case number), 97 fEVAR TVS were analyzed. Five thrombosis and 7 endoleaks were observed. While anatomical configuration showed no association to thrombosis, it was related to endoleak: these cases presented more tortuous stents (5.97% +/- 0.10, 21.40% +/- 0,22, P = 0.011), with more angulated centre-lumen-line at ABC segment (5.69 degrees +/- 15.77 degrees, 7.18 degrees +/- 7.77 degrees, P = 0.012), and more upward-pointing stents in the origin of the stent (AB: 89.07 degrees +/- 24.46 degrees, 109.09 degrees +/- 16.56 degrees, P = 0.012; BC: 87.86 degrees +/- 21.10 degrees, 113.11 degrees +/- 22.23 degrees, P = 0.026). Conclusions: Anatomical configuration of the TVS is associated with type III endoleak, but not thrombosis, at 1-year following fEVAR. Cases with endoleak presented more tortuous stents, with a more angulated exit from the endograft, and upward-pointing of the origin of the stent.