Advanced Intraoperative Imaging and Novel Interventions in Endovascular Aortic Repair

Abstract

This thesis evaluated advanced intraoperative imaging, artificial intelligence (AI), and a novel injectable polymer to improve the feasibility, safety, and long-term durability of endovascular aneurysm repair (EVAR), with the aim of enhancing intraoperative decision-making and reducing complications in patients treated for abdominal aortic aneurysms (AAA). Part I. Advanced Intraoperative Imaging in the Hybrid Operating Room Image fusion (Chapter 2): A systematic review and meta-analysis showed that three-dimensional image fusion significantly reduces contrast use, fluoroscopy time, and procedure time, particularly in complex fenestrated or branched EVAR. In complex EVAR, fusion imaging reduced contrast volume by 79 mL, fluoroscopy time by 14 minutes, and total procedure time by 52 minutes. In standard EVAR, reductions were more modest but remained significant for contrast volume (29 mL) and procedure time (11 minutes). Radiation dose was not significantly different. Automated fusion registration (Chapter 3):*An automated 2D–3D image fusion registration algorithm achieved non-inferior accuracy compared with manual bone landmark alignment. The median difference in vertebral alignment was 0.1 mm, while renal artery ostium alignment errors were similar, demonstrating that this operator-dependent registration step can be automated without loss of precision. AI for intraoperative DSA (Chapters 4–5): A deep learning model segmented the stent graft on completion digital subtraction angiography (DSA) with high accuracy (Dice 0.96). A multitask model detected endoleaks with an AUC of 0.85, F1 score of 0.78, 95% precision, and 73% recall, outperforming the procedural team in recall. Interobserver agreement among clinicians was only moderate, highlighting the subjectivity of DSA interpretation and the potential of AI to support more consistent intraoperative decision-making. Sac dynamics and intraoperative DSA (Chapter 6): Combining preoperative infrarenal branch anatomy with completion angiography improved prediction of long-term sac dynamics. In patients with low-risk anatomy (<6 patent lumbar arteries and an inferior mesenteric artery <3 mm), an endoleak-free completion DSA was associated with more frequent sac shrinkage (18.4% vs. 5.7%). In high-risk anatomy, completion angiography did not add predictive value. Part II. Novel Image-Guided Interventions Polymer-based type II endoleak treatment (Chapters 7–8): In patients with persistent type II endoleak and aneurysm sac growth after EVAR, translumbar direct sac puncture and embolization with the injectable polymer AneuFix achieved high technical success, both in the initial clinical experience (100%, n=10) and the midterm cohort (96%, 48/50). Freedom from sac expansion was 75% at 6 months, 56% at 12 months, and 50% at 24 months, indicating early sac stabilization but declining durability over time. These findings reflect a challenging salvage population with a mean pre-treatment aneurysm diameter of 79.6 ± 15.4 mm and prior failed embolization in 40% of patients. Procedure- or device-related serious adverse events occurred in 4% and reinterventions in 22%, underscoring the need for careful patient selection and continued imaging surveillance. Aneurysm sac filling for type II endoleak prevention (Chapters 9–10): In a first-in-human feasibility study in patients at high risk of type II endoleak, prophylactic sac filling with AneuFix during EVAR was technically successful in all five cases. One procedure-related access complication occurred and resolved without sequelae. At 12 months, median aneurysm diameter decreased from 62 mm to 56 mm, and no type I, II, or III endoleaks were observed on assessable imaging. These preliminary findings suggest that intraoperative sac filling may support a more proactive strategy for preventing type II endoleaks and warrant further clinical investigation as an adjunct to the index EVAR procedure. By linking enhanced intraoperative assessment to targeted sac interventions at the index procedure, this thesis outlines a pathway toward more durable and personalized endovascular aneurysm repair for patients.