Bioresorbable stents (BRS) represent the latest generation of vascular scaffolds used for minimally invasive interventions. They aim to overcome the shortcomings of established bare-metal stents (BMS) and drug-eluting stents (DES). Recent advances in the field of bioprinting offer the possibility of combining biodegradable polymers to produce a composite BRS. Evaluation of the mechanical performance of the novel composite BRS is the focus of this study, based on the idea that they are a promising solution to improve the strength and flexibility performance of single material BRS. Finite element analysis of stent crimping and expansion was performed. Polylactic acid (PLA) and polycaprolactone (PCL) formed a composite stent divided into four layers, resulting in sixteen unique combinations. A comparison of the mechanical performance of the different composite configurations was performed. The resulting stresses, strains, elastic recoil, and foreshortening were evaluated and compared to existing experimental results. Similar behaviour was observed for material configurations that included at least one PLA layer. A pure PCL stent showed significant elastic recoil and less shortening compared to PLA and composite structures. The volumetric ratio of the materials was found to have a more significant effect on recoil and foreshortening than the arrangement of the material layers. Composite BRS offer the possibility of customising the mechanical behaviour of scaffolds. They also have the potential to support the fabrication of personalised or plaque-specific stents.

Vascular pathology often manifests in complex shape evolution visualized by longitudinal computed tomography (CT) imaging. Growth and remodeling (G&R) frameworks have been integrated into finite element (FE) modeling to probe the mechanics underlying this progression, extending into patient-specific approaches. Their scalability and translatability, however, are limited by the computational burden associated with heterogeneous, anisotropic growth fields and through-thickness meshing. While existing shell growth formulations can mitigate this burden, they require nontrivial FE implementation especially in commercial softwares (e.g., Abaqus) and their efficacy in patient-specific geometries under complex loading is unclear. In this work, we present a general computational framework to implement shell morphoelastic growth computed directly from registered patient-specific CT images. This shell implementation is validated against solid 3D formulations, allows thickness tunability, and increases compatibility with CT surfaces. We demonstrate the robustness of this formulation through modeling post-operative growth in a patient-specific aortic dissection under stent-based loading. Results first show that complex stent-based loading can deform the shell dissection flap to reproduce post-operative geometry. The outer aortic wall is then given a growth field calculated from registration of 1-month and 5-year post-operative CT images, which is implemented along with stent-based loading and pressurization. Results from this model capture the trends in total and lumen morphological evolution observed at intermediate timepoints. These findings establish a general framework, validated with a patient-specific case study of aortic dissection, with the potential to expand to other complex systems, scale to larger patient populations, and apply G&R to clinical translation.