Techniques to reduce radiation and contrast volume during EVAR

Abstract

There is a large variability observed in the literature regarding radiation exposure and contrast volume injection during endovascular aortic repair (EVAR). Reducing both in order to decrease their respective toxicities must be a priority for the endovascular therapist. Radiation dose reduction requires a strict application of the "as low as reasonably achievable" principles. Firstly, all X-ray system settings should be defaulted to low dose, and fluoroscopic time reduced as much as possible. Digital subtraction angiography runs should be replaced by recorded fluoroscopy runs when possible. Magnification should be avoided, whereas collimation should be systematic to minimize scatter radiation and focus only on the area of interest. Advanced imaging modes can also contribute to dose reduction. For instance, image fusion can facilitate endovascular navigation, and allow table and C-arm positioning without fluoroscopy. In our experience, routine use of image fusion during EVAR significantly reduces both radiation exposure and contrast volumes during complex EVAR. To make these imaging modes useable in real life settings, the X-ray system should be fully controlled by the operator from table side. Reducing iodinated contrast volume, while maintaining image quality, can also be achieved through the use of automated contrast injectors. Additionally, alternative contrast agents, like carbon dioxide (CO2) and gadolinium, have also been evaluated and can be used in specific cases. Contrast-enhanced ultrasound and intravascular ultrasonography are currently developed as potential alternatives to both iodinated contrast use and X-ray during EVAR. Lastly, specific education and training of operators in radiation protection are essential.