Inter-Center Radiation Variability in CO₂-Guided EVAR: Lessons From the Zero Iodine Contrast Multicenter Prospective...

Area of Science:

• Interventional Cardiology
• Medical Imaging
• Radiation Safety

Background:

• Current diagnostic reference levels (DRLs) for EVAR using iodinated contrast media (ICM) range from 100 to 200 Gy·cm².
• Carbon dioxide (CO2) angiography, a negative contrast agent, may increase radiation exposure during EVAR.
• This study evaluates radiation dose in CO2-guided EVAR using digital subtraction angiography (DSA) with an automated injector.

Purpose of the Study:

• To assess radiation dose metrics (DAP and Kar) during CO2-guided EVAR across multiple centers.
• To identify factors influencing radiation dose, including angiographic system generation and protocols.
• To evaluate optimization strategies for reducing radiation exposure in CO2-guided EVAR.

Main Methods:

• Prospective, multicenter, observational study of dosimetry during CO2-guided EVAR.
• Recorded dose-area product (DAP) and reference air kerma (Kar) as primary endpoints.
• Investigated optimization strategies at a single site to reduce patient and operator radiation exposure.

Main Results:

• 293 patients across 10 centers showed median DAP of 189 Gy·cm² (IQR 107-285) and Kar of 626.5 mGy (IQR 145.5-1373.5).
• Significant inter-center variability in radiation dose was observed (p<0.001).
• Newer angiographic systems (median DAP 90 Gy·cm²) showed lower dose than older systems (191 Gy·cm²; p<0.001).
• Optimization strategies, including low-dose protocols and synchronized CO2-DSA, achieved a 56% overall reduction in median DAP to 28.5 Gy·cm².

Conclusions:

• CO2-guided EVAR radiation dose varies significantly based on equipment and protocols.
• Modern systems with optimized low-dose protocols and CO2-DSA synchronization yield radiation doses comparable to ICM-based EVAR.
• This study establishes radiation dose benchmarks for CO2-guided EVAR, confirming its safety and efficacy.