Carbon Dioxide Flushing and Endograft De-airing in Aortic Repair: A Systematic Evidence Map

Endovascular aortic repair relies on large-bore endograft delivery systems that require intraluminal preparation prior to deployment. Despite standard flushing practices, experimental and clinical observations have demonstrated that residual air or gas may remain within these systems and be released during endograft deployment. Over the past decade, this has prompted increasing interest in endograft de-airing strategies, particularly the use of carbon dioxide (CO₂) flushing, as a means of reducing gaseous embolic exposure. The literature addressing endograft de-airing spans multiple methodological domains, including bench and flow-model experiments, device-handling and technique descriptions, clinical imaging studies evaluating postoperative gas, and early-phase clinical trial protocols. Translation of this evidence into patient-centred clinical outcomes varies substantially between thoracic endovascular aortic repair (TEVAR) and endovascular aneurysm repair (EVAR), and the overall evidence base is heterogeneous in both design and outcomes assessed. This project aims to conduct a systematic evidence map of studies evaluating endograft de-airing strategies, with particular focus on CO₂ flushing, across experimental, translational, and clinical settings in aortic endovascular repair. Rather than synthesising effect estimates, this work will catalogue and categorise the existing evidence according to intervention type, procedural context (TEVAR vs EVAR), and outcome domain, including gas-related surrogate outcomes, embolic surrogate measures, and clinical endpoints. Expected outputs include a comprehensive descriptive summary of the existing literature, visual evidence-mapping tools (such as heatmaps and translational ladders) illustrating where evidence is concentrated and where gaps remain, and a conceptual framework to contextualise de-airing strategies within broader procedural injury pathways. The findings are intended to inform future hypothesis-driven studies and guide the design of outcome-focused investigations in this area. At the time of registration, database searching has been piloted for search-strategy validation only. Formal screening, eligibility assessment, and data extraction have not yet commenced.