Safety and evidence of CO2 as a vascular contrast agent as an alternative to iodine-based contrast media in vascular procedures: a systematic review by the ESUR Contrast Medium Safety Committee

Objectives: This systematic review aims to analyse the different safety aspects and evidence of CO2 as a contrast agent in vascular applications as an alternative to iodine-based contrast media (ICM). The review addresses clinical applications, contraindications, safety measures, and the impact of CO2 on the risk reduction of contrast-associated acute kidney injury (CA-AKI). Materials and methods: A systematic literature search was conducted across PubMed, Web of Science, Embase, and Cochrane Library, focusing on relevant literature centred around clinical questions by the Contrast Media Safety Committee of the European Society of Urogenital Radiology. Results: Eleven studies encompassing meta-analyses, randomised controlled trials, and comparative studies were included. The review found that CO2 angiography is a safe alternative to ICM in various vascular applications, especially in patients at risk for CA-AKI. CO2 is associated with a higher incidence of minor, non-serious adverse events compared to ICM. No critical dose for CO2 is established, but safe administration protocols and measures were outlined. CO2 demonstrated a lower incidence of CA-AKI in peripheral arterial disease (PAD) procedures, but evidence in endovascular aneurysm repair (EVAR) was less conclusive. Conclusion: CO2 is a safe alternative to ICM in vascular procedures, potentially reducing the risk of CA-AKI, especially in PAD procedures. However, more large-scale RCTs are needed to confirm these findings and further investigate other risk factors contributing to CA-AKI in both EVAR and PAD procedures. Key Points: Question What safety aspects and evidence support CO2 use as a contrast agent in vascular applications instead of ICM? Findings CO2 angiography is safe when considering specific safety measures and clinical applications; evidence on the reduction of ICM volume and CA-AKI is limited. Clinical relevance CO2 angiography offers an alternative to ICM, especially in CA-AKI risk patients. More large-scale, multicentre RCTs are required to strengthen the evidence and to investigate other risk factors due to a high residual risk of CA-AKI when using CO2 angiography.