Prediction of guidewire-induced aortic deformations during EVAR: a finite element and in vitro study

FIGURE 1. The three manufactured models used for experiments, from left to right (A) without intraluminal thrombus (ILT) (Model A), (B) with ILT (indicated by the white arrow) (Model B), (C) with ILT and calcifications (indicated by white arrows) (Model C).

FIGURE 2. (A) Detail of the CBCT scanner in the hybrid operating room, with the model placed in a rigid box. (B) Example of a CBCT acquisition, with the reference markers used for registration. (C) Detail of the additive manufactured (AM) model (Model A) with the guidewire fully inserted.

FIGURE 3. Resulting stress (σ nom)—strain (ϵ nom) curve obtained from uniaxial loading test of the materials used to manufacture the aorta and the ILT (with a detail of the specimen used for uniaxial loading test).

FIGURE 4. Details of the parts of the computational model: aorta with anatomical details, guidewire with flexible tip and introducer. The displacement of the nodes enclosed in the rectangular area were constrained (Boundary conditions).

FIGURE 5. Average values of deformations, d from experiments and FEA for the entire abdominal aorta (A) and for different anatomical positions: bifurcation region (B), aortic neck (C) and ostium of the left renal artery (D); for Model A without ILT, Model B with ILT, Model C with ILT and calcifications, indicated as A, B, C in the graphs.

FIGURE 6. Experimental deformations from CBCTs, d EXP. Anterior views: (A) Model A without thrombus, (B) Model B with thrombus, (C) Model C with thrombus and calcifications. Posterior views: (D) Model A without thrombus, (E) Model B with thrombus, (F) Model C with thrombus and calcifications.

FIGURE 7. Deformations obtained from FEA, d FEA. Anterior views: (A) Model A without thrombus, (B) Model B with thrombus, (C) Model C with thrombus and calcifications. Posterior views: (D) Model A without thrombus, (E) Model B with thrombus, (F) Model C with thrombus and calcifications.

FIGURE 8. FEA Results: path of the guidewire (light blue), initial aortic configuration (grey), final deformed aortic configuration (pink). Anterior view, frontal plane. (A) Model A without ILT, (B) Model B with ILT, (C) Model C with ILT and calcifications.

FIGURE 9. From left to right, deformations d FEA between the initial vs. final configuration when the initial position of the guidewire is (A) centered on the iliac inlet, in a vertical position (0°inclination in frontal and sagittal planes) (B) 20°counterclockwise inclination in frontal plane, (C) 25°clockwise inclination in sagittal plane, (D) 20°clockwise inclination in frontal plane.

FIGURE 10. Error (e aorta) between the simulated and experimental final aortic configurations. Anterior views: (A) Model A without thrombus, (B) Model B with thrombus, (C) Model C with thrombus and calcifications. Posterior views: (D) Model A without thrombus, (E) Model B with thrombus, (F) Model C with thrombus and calcifications.