Related Experiment Video
Updated: Jul 29, 2026
A New Murine Model of Endovascular Aortic Aneurysm Repair
Published on: July 7, 2013
First-generation aortic endografts: analysis of explanted Stentor devices from the EUROSTAR Registry
R Guidoin1, Y Marois, Y Douville
1Department of Surgery, Laval University, and Québec Biomaterials Institute, CHUQ, Québec City, Canada. robert.guidoin@crsfa.ulaval.ca
Insights
Explanted Stentor endografts showed fabric damage and incomplete healing. Nitinol wires exhibited corrosion and non-uniform elemental composition, indicating a need for improved biomaterial assembly in endovascular grafts.
Area of Science:
- Biomaterials Science
- Medical Device Engineering
- Vascular Surgery
Background:
- Endovascular grafts are crucial for treating aortic aneurysms.
- Long-term performance of implanted devices requires thorough evaluation.
- Stent-graft structural integrity and host tissue interaction are key concerns.
Purpose of the Study:
- To investigate the structural integrity and healing characteristics of explanted Stentor endografts.
- To identify failure modes and material degradation in chronically implanted devices.
Main Methods:
- Explantation of Stentor endografts after 13-53 months of implantation.
- Radiography, endoscopy, and MRI for structural analysis.
- Histology, SEM, and chemical analysis for material and healing assessment.
Main Results:
- Woven polyester fabric showed distortion, damage, and breakage, creating openings.
- Incomplete luminal healing with a nonadherent thrombotic matrix was observed.
- Nitinol wire corrosion and non-uniform titanium/nickel distribution were noted, alongside metallic frame compaction and dislocation.
Conclusions:
- Despite judicious material selection, the assembly of biomaterials in Stentor endografts requires enhancement.
- Fabric integrity, healing response, and nitinol stability are critical areas for improvement.
Purpose:
To examine the structure and healing characteristics of chronically implanted Stentor endografts that were explanted due to migration, endoleak, thrombosis, or aneurysm expansion.
Methods:
The devices were harvested following reoperation (n = 5) or autopsy (n = 1) with implantation times ranging from 13 to 53 months. Structural modifications to the metal components were examined using radiography, endoscopy, and magnetic resonance imaging (MRI). Specimens taken from components of the modular stent-grafts were examined histologically and with scanning electron microscopy (SEM) to assess healing behavior. Physical and chemical stability of the nitinol wires and woven polyester graft material was evaluated using SEM and electron spectroscopy for chemical analysis.
Results:
Although the endografts were retrieved for a variety of reasons, they exhibited similar healing and structural modifications. The woven polyester sleeve showed evidence of yarn shifting and distortion, yarn damage, and filament breakage leading to the formation of openings in the fabric. The luminal surface endografts showed incomplete healing characterized by a poorly organized, nonadherent thrombotic matrix of variable thickness. Radiographic and endoscopic observations indicated that structural failure of the grafts, particularly in the main aortic component, was related to severe compaction and dislocation of the metallic frame due to suture breaks. Corrosion marks were observed on some nitinol wires in all devices. Chemical analysis and ion bombardment of the nitinol wires revealed that the surface concentrations of titanium and nickel were not homogenous. The first layer was composed of carbon or organic elements, followed by a stratum of highly oxidized titanium with a low nickel concentration; the titanium-nickel alloy lay beneath these layers.
Conclusions:
Although the materials selected for construction of endovascular grafts appears judicious, the assembly of these biomaterials into various interrelated structures within the device requires further improvement.
