Limb graft occlusion after endovascular abdominal aortic aneurysm repair: Hemodynamic and morphological insights

Endovascular aneurysm repair (EVAR) has become a cornerstone of modern vascular practice, offering a minimally invasive alternative to conventional open surgery for the treatment of abdominal aortic pathologies. Its efficacy can be undermined by limb invasive alternatives. However, its graft occlusion (LGO) is a complication characterized by thrombotic obstruction. To investigate the hemodynamic and morphological characteristics of LGO-affected limbs, we performed morphological measurements and hemodynamic simulations on 22 patient-specific geometries collected from a tertiary center. Logistic regression models were applied to identify prognostic factors. In addition, using computer-aided design technology, we modeled two different intervention strategies to explore the impact of virtual surgery on the progression of thrombosis in occluded limbs. Our analysis revealed that the LGO group exhibited significantly higher values for relative residence time, oscillatory shear index (OSI), and endothelial cell activation potential (ECAP), alongside significantly lower time-averaged wall shear stress (p < 0.001). Morphological assessments showed significantly increased limb cannulation stenosis rates (p < 0.001) in the LGO group. Multivariate regression analysis identified OSI and limb cannulation stenosis rate as independent predictors of LGO. Building on this, a predictive nomogram incorporating these two parameters was developed. These findings highlight the importance of combining hemodynamic and morphological assessments to predict and prevent LGO, and the nomogram we developed can effectively support this process. In addition, combining virtual surgery with hemodynamic simulation can be a novel paradigm in the perioperative management of EVAR patients.