Advancing Simulated Use Testing with Silicone Vascular Models

In June 2025, Bentley collaborated with Hôpital Marie Lannelongue (HML) in Paris to evaluate the new BeGraft Plus stent graft system in a realistic, perfused vascular environment. Led by HML’s surgical team, the objective was to reproduce the full clinical workflow of a branched endovascular aortic repair (BEVAR) of an abdominal aortic aneurysm (AAA) from access and navigation to positioning and deployment — using anatomically accurate silicone models manufactured by 3Deus Dynamics.

This study served as a key opportunity for Bentley to examine how their bridging stent behaves under controlled physiological conditions, without relying on animal or cadaver models.

Setting the Scene: The Need for Anatomical Fidelity

BeGraft Plus stent graft system is designed for usage as a bridging stent for the celiac trunk, superior mesenteric artery, and renal arteries in complex AAA requiring BEVAR. Assessing such a device requires more than a static bench model. Bentley needed an environment that would accurately replicate:

  • The patient’s lumen diameters,
  • The compliance of the aortic wall,
  • Radiotransparency for fluoroscopic guidance, and
  • the precise geometry of the aorto-iliac tree and its visceral branches.

To achieve this level of fidelity, HML relied on CT scan images to measure the required anatomical parameters and confirmed that the anatomies produced by 3Deus Dynamics fully respected the STL-derived specifications, enabling a smooth and clinically relevant evaluation.

Traditional simulated use options — such as cadavers, animal models, or non-perfused bench setups (“dry benches”) — offer limited repeatability and do not allow precise control over diameters and geometry.

Mounted on HML’s pulsatile, temperature-controlled perfusion bench, the 3Deus Dynamics anatomies were integrated into a platform that replicated physiological conditions through controlled flow, stable supports, and dedicated entry points for vascular access. This setup provided surgeons with a realistic tactile and visual environment in which to navigate, position, and deploy the bridging stent. The radiotransparent silicone enabled fluoroscopy-guided procedures, while the controlled compliance of the models allowed meaningful observation of device behavior throughout the workflow.

From DICOM to Silicone: Delivering Four Anatomical Variants

To support Bentley’s evaluation strategy, 3Deus Dynamics created four silicone aortic models, each representing the same pathology but with calibrated variations in key diameters. The addressed target vessels in a BEVAR procedure are the visceral arteries, which contain the celiac trunk (CT), the superior mesenteric artery (SMA), and the left and right renal artery (LRA and RRA). The bridging stent sizes for connecting visceral arteries to the endograft were selected by medical professionals. The selection followed the same procedure as in standard clinical preimplantation planning in BEVAR cases.

The anatomic models used in this study are based on a patient’s thoraco-abdominal aneurysm, suitable for the implantation of this model in all target vessels. The 3D models tested in the study represent a large percentage of the intended patient population for this bridging stent, but also cover angles that represent worst-case angulations.

Each model reproduced the vascular route necessary for BEVAR: from the aortic root to the iliac arteries, including the celiac trunk, the superior mesenteric artery (SMA), the right and left renal arteries, and three access points (bilateral femoral and brachiocephalic). This architecture ensured that navigation, alignment, and deployment of the bridging stent would be evaluated in clinically realistic conditions.

To ensure repeatability, each anatomy was manufactured with a standardized connector system for the celiac trunk, visceral branches, and iliac arteries, allowing consistent mounting across all four models.

Inside the Evaluation: A Full Procedural Workflow

During the session, the surgical team at HML followed a complete BEVAR workflow, beginning with vascular access through the femoral and brachiocephalic paths. They navigated guidewires and catheters through the pulsatile aortic lumen, positioned the device at the visceral target lesions, and deployed the bridging stent while monitoring its interaction with the anatomy and the endovascular graft.

Critical verification zones included:

  • bridging stent apposition and sealing in target lesions
  • alignment of the bridging stents with the branches of the endovascular graft
  • interaction between guidewires, catheters, and bridging stents with the visceral branch ostia during navigation and deployment

What’s next

The successful completion of the study confirmed that the silicone anatomies based on real patient anatomies met the dimensional and mechanical requirements needed for a realistic evaluation. Mounted on the perfusion bench, the anatomies provided a credible environment for navigation, alignment, and deployment of Bentley’s BeGraft Plus stent graft system, and the variations across the four models made it possible to compare behavior under different anatomy conditions.

By offering a controlled and repeatable alternative to cadaveric or animal testing, this approach supports more ethical and standardized simulated use evaluations and contributes to the ongoing efforts toward FDA (Food and Drug Administration) recognition of these vascular models as Medical Device Development Tools or MDDTs.

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