Abdominal Stent Graft Numerical Models to Virtually Simulate Endovascular Aortic Repair: A Scoping Review

Endovascular aortic repair (EVAR) is a common procedure used to treat abdominal aortic aneurysms. This scoping review aimed to identify the numerical methods currently available in the literature to analyse the surgical applicability and credibility of this procedure from a structural and fluid dynamic perspective.

PubMed (MEDLINE), Scopus, and Web of Science were systematically searched. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews were followed. Data were analysed and summarised in tables. Quality assessment was performed using a 14 item rating rubric.

This scoping review identified 28 articles published in the last 10 years. Most of these articles were of intermediate to good quality. Seventeen articles (61%) focused on post-EVAR haemodynamics, performing computational fluid dynamics simulations. Six articles (21%) aimed to develop new methods to reproduce the EVAR procedure through finite element analysis. Five articles (18%) addressed the coupling between fluids and structures by performing a fluid-structure interaction simulation of the EVAR procedure. Studies using computational fluid dynamics demonstrated a more homogeneous approach in the selection of blood models, discretisation, and boundary conditions. Studies using finite element analysis adopted different strategies to reproduce the EVAR procedure in silico, with no common methodology identified. The choice of material properties assigned to the aorta, graft, and stent was highly heterogeneous. Four studies (16%) on fluid-structure interaction published in the last 10 years were identified. A Newtonian model for the blood was adopted in all the articles (100%), and in three articles (75%), a velocity waveform was applied as inlet boundary condition. For the structural part, more heterogeneities were found.

This review provides an overview of the existing computational models to reproduce the EVAR procedure. Although promising, these simulation techniques remain largely in the developmental phase, and robust clinical validation is lacking. Future studies should incorporate clinically relevant outcome data to enhance the credibility and translational value of these models.