Renal Benefits of CO2 as a Contrast Media for EVAR Procedures: New Perspectives on 1 Year Outcomes

Background and Objectives: Endovascular aneurism repair (EVAR) is a minimally invasive alternative to open surgery for the treatment of abdominal aortic aneurysm. Iodine contrast medium (ICM) is considered the gold standard, at the high price of related nephrotoxicity and allergic reactions. Carbon dioxide (CO2) has been suggested as an alternative non-nephrotoxic contrast media agent. We aimed to evaluate the safety and the renal impact of the administration of CO2, compared with ICM in EVAR procedures. Design, Setting, Participants, and Measurements: We retrospectively reviewed data of patients who underwent EVAR at the Vascular Surgery Department of the Sant'Orsola Hospital in Bologna. Estimated glomerular filtration rate (eGFR) was evaluated before intervention, immediately after and at 12 months. Results: In total, 22 patients received CO2 and low-dose ICM (CO2 Group) and 22 received standard ICM (Control Group), matched for clinical characteristics and renal function at the time of procedure. Pre and post-operative renal function values (eGFR) were compared between the two groups: in the immediate post-operative the group treated with CO2 and low-dose ICM globally showed a slight improvement in renal function (mean eGFR +5.10%+/- 3.2), meanwhile the group treated with standard dose of ICM presented a significant worsening of renal function compared with pre-procedure values (mean eGFR -9.65%+/- 4). Incidence of post-contrast acute kidney injury (PC-AKI) was 9% in the CO2 group vs 27% in the Control group. At 12 months, the renal impairment was significantly greater in the ICM group than in the CO2 group (mean eGFR decrease -19.2%+/- 11.1 and -7.40%+/- 3.5, respectively). Conclusions: Administration of either CO2 alone or along with low-dose ICM showed to be safer than full-dose ICM alone, lowering the incidence of PC-AKI in patients undergoing EVAR. Unexpectedly, our study revealed also a significant worsening of renal function in patients treated with standard dose of ICM in 1-year follow-up, introducing the concept that acute renal damage caused by ICM could elicit a chronic injury process that affect long-term renal outcomes. Clinical Impact Evaluating the safety and the renal impact of the administration of CO2, compared to Iodinate Contrast Medium, in EVAR procedures represents a first step in order to further tayloring medical procedures on patients characteristics. Our findings can guide the clinicians and surgeons in the procedures choice, not considering only the immediate effect of ICM on renal function but also the potential long-term effects.