Patient-specific hemodynamic evaluation of fenestrated physician-modified endografts in complex abdominal aortic aneurysms

Abstract

Physician-modified endografts (PMEGs) are increasingly used for complex abdominal aortic aneurysms (AAA), but the patient-specific flow consequences of the geometric reconstruction are not well quantified. This study evaluated PMEG-associated changes in hemodynamic and wall-mechanical surrogate markers. Eight patients were retrospectively analyzed. Pre- and post-PMEG geometries were reconstructed from computed tomography angiography and simulated with pulsatile computational fluid dynamics under matched inlet and outlet conditions. Time-averaged wall shear stress relative residence time and endothelial cell activation potential were quantified; one representative case underwent fluid-structure interaction analysis. Mean velocity increased from approximately 0.8–1.5 m/s ( P = 0.0021), pressure drop decreased ( P = 0.0183), low-shear regions became less extensive, and RRT and ECAP decreased significantly (both P < 0.05). FSI showed lower computed wall deformation after repair. At 1 year, all branch stents remained patent, with no endoleak or reported adverse event. Together with prior paired PMEG simulations, these findings support a favorable hemodynamic and wall-mechanical effect of PMEG in complex anatomy unsuitable for conventional infrarenal EVAR and suggest a less stasis-prone postoperative environment. Larger controlled cohorts remain necessary to determine whether these surrogate changes translate into fewer clinical thrombotic or rupture events. The observed changes arise from PMEG-induced geometric remodeling, which modifies local flow acceleration, separation, near-wall shear, and pressure-loss characteristics.