Abstract
OBJECTIVE: Carbon dioxide (CO(2)) has been proposed as a contrast agent during endovascular aortic repair (EVAR) to minimise the risk of worsened post-operative renal function (PO-RFW). However, strong clinical evidence supporting its widespread use remains limited. This systematic review aimed to evaluate current literature on the use of CO(2) digital subtraction angiography (DSA) during EVAR, with particular attention to renal outcomes and procedural efficacy. DATA SOURCES: Systematic searches were conducted in PubMed, Scopus, and the Cochrane Library for studies published up to December 2024 reporting the use of CO(2)-DSA during standard EVAR. REVIEW METHODS: The review was registered prospectively in the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD42024580889). All papers reporting the use of CO(2)-DSA during EVAR were included. The primary outcome was the incidence of PO-RFW, and secondary outcomes included procedural success, arterial image visualisation quality, endoleak detection, and radiation exposure. RESULTS: Of the 108 articles initially identified, 16 studies published between 2007 and 2024 met the inclusion criteria, reporting data on 901 patients (mean age 76 years; 89.1% men) undergoing EVAR with CO(2)-DSA. Among these, 622 (69.0% ) were treated exclusively with CO(2)-DSA. All studies published since 2018 adopted an automatic injector. Seven studies comparedPO-RFW using different definitions; three of the included studies reported a statistically significantrole for CO(2)-DSA in renal protection. Three studies reported a higher dose of radiation during CO(2)-EVAR. Renal and hypogastric arteries were effectively visualised during repair in 53-100% and 94-100% of cases, respectively. Data on endoleak detection were heterogeneous, limiting definitive conclusions. CONCLUSION: The use of CO(2) as contrast medium in EVAR appears to be safe and effective. Evidence suggests potential benefits for renal protection, although inconsistencies are reported regarding study design and outcome definitions. Further research is necessary to standardise CO(2) delivery, imaging assessment criteria, and renal outcome definitions. To standardise clinical practice, a defined protocol is needed to maximise its advantages in everyday practice.