Computational Fluid Dynamics Predicting Intraprosthetic Thrombus Formation and Burden Following Endovascular Aortic...

To evaluate the predictive value of post endovascular aneurysm repair (EVAR) morphological and hemodynamic parameters for intraprosthetic thrombus (IPT) formation and thrombus burden, using a combination of computed tomography angiography (CTA) and computational fluid dynamics (CFD).

In this two-center retrospective case-control study, 76 patients who underwent EVAR between 2019 and 2024 were analyzed, including 38 with IPT and 38 matched controls selected by risk-set sampling. Morphological parameters were obtained from preoperative and postoperative CTA, and hemodynamic metrics were derived from CFD simulations under rigid-wall assumptions. Logistic regression and receiver operating characteristic analyses assessed predictors of IPT. Thrombus burden was categorized as mild (<50%) or severe (≥50%), with supplementary analyses treating burden as a continuous variable. Associations were further examined using ordered logistic and linear regression.

Patients with IPT had greater iliac angulation and more frequent iliac artery aneurysms and landing zones. Hemodynamic parameters, including elevated maximum relative residence time (RRT_max), maximum oscillatory shear index, their surface-averaged value (RRT_mean, and mean oscillatory shear index), and reduced mean time-averaged wall shear stress, were significantly associated with IPT. RRT_max demonstrated the highest predictive value for IPT formation (area under the curve [AUC] 0.8604 95% 95% confidence interval [CI] 0.7865∼0.9343; P < 0.0001) and showed a strong positive correlation with thrombus burden (R² = 0.63; P < 0.001). In contrast, anatomical features alone were not independently associated with IPT formation and severity.

CFD-derived hemodynamic parameters, particularly RRT_max, outperform conventional anatomical indices in predicting IPT formation and thrombus burden following EVAR, supporting their use in postoperative surveillance.