Safety, Effectiveness and Pitfalls of Carbon Dioxide Routine Use as a Contrast Agent for Endovascular Abdominal Aortic Repair.

Background: Despite the evidence of good performance, carbon dioxide (CO) routine employment as a contrast agent for endovascular procedures is far from being adopted with its use currently limited to patients with renal impairment and known allergy to iodinated contrast medium (ICM). The purpose of our study is to evaluate the safety and effectiveness of CO guided endovascular abdominal aortic aneurysm repair (EVAR) in a standard population and to assess the rationale for a future widespread use.

Methods: We retrospectively collected data of every patient who underwent CO guided standard EVAR from September 2020 to May 2021 and compared them with the data of every patient who underwent EVAR using ICM from December 2019 to August 2020 in our unit. The selection of the contrast medium was not based on any preoperative factor as the contrast medium was routinely used in every patient in both periods. The primary end point of the study was the technical success rate. Secondary end points were the early and late complication rates, radiation exposure and renal function impairment.

Results: 49 patients underwent ICM guided EVAR and 52 patients underwent CO guided EVAR in our unit in the time frames specified above. The technical success rate was 100% in both groups with no accidental coverage of any target vessel. Intraoperative endoleaks were observed in 14% of ICM patients and 25% of CO patients. The radiation exposure was higher in the CO group if compared to the ICM group (311.48 vs. 159.86 median mGy/cm - P < 0.001). The incidence of postoperative acute kidney injury was low and similar in the 2 groups. No significant worsening over time of the renal function has been reported in both groups.

Conclusions: EVAR can be safely performed under CO guidance without the integration of any quantity of ICM but with an increase in radiation exposure. The nephroprotective role of CO guided EVAR in a standard population is unclear and the same role in renal impaired patients should be validated with further studies on selected populations.