The optimal operative protocol to accomplish CO₂-EVAR resulting from a prospective interventional multicenter study

Area of Science:

• Vascular Surgery
• Medical Imaging
• Interventional Radiology

Background:

• Carbon dioxide (CO2) angiography for endovascular aortic repair (CO2-EVAR) is crucial for patients with chronic kidney disease or iodinated contrast medium (ICM) allergies.
• Technical challenges persist in visualizing the lowest renal artery (LoRA) and achieving optimal image quality during CO2-EVAR.

Purpose of the Study:

• To analyze various stages of CO2-EVAR to develop a standardized operative protocol.
• To optimize visualization of the LoRA and enhance overall image quality in CO2-EVAR procedures.

Main Methods:

• Prospective enrollment of 65 patients undergoing CO2-EVAR across five European centers (2019-2021).
• Utilized an automated injector for CO2 delivery, with limited ICM use for difficult LoRA visualization.
• Analyzed LoRA visualization and image quality at distinct procedural steps, including preoperative, during main body deployment, and completion angiograms.

Main Results:

• Preoperative CO2 angiography from the femoral introducer sheath yielded significantly higher image quality compared to the pigtail.
• LoRA detection and image quality improved significantly during main body deployment at 50% and 100% stages.
• Contralateral hypogastric artery (CHA) visualization was successful in 93% of cases; completion angiograms from the introducer sheath showed superior image quality.

Conclusions:

• Preimplant and completion CO2 angiography should be performed from the femoral introducer sheath for optimal results.
• Gas flow impediment during main body deployment enhances LoRA visualization and image quality.
• The developed protocol facilitates CO2-EVAR with minimal ICM and a low incidence of mild, transient adverse events.