Background: Carbon dioxide (CO₂) is the only proven safe intravascular contrast agent in renal failure and contrast allergy. The use of CO₂ as a contrast agent for the evaluation of failing dialysis fistulas has the potential to preserve residual renal function by eliminating the use of contrast material or decreasing the amount used for fistulograms.
Purpose: To evaluate the feasibility of fistulography using CO₂ for diagnosis and intervention in patients with failing hemodialysis access.
Material and methods: Dialysis access failure occurred in 94 patients (54 men, 40 women; mean age, 65 years; range, 32–89 years) on 146 occasions. CO₂ was used as the first-choice contrast agent for fistulography and PTA. Fistulography was performed with the injection of CO₂ in the brachial artery using a power injector.
Results: Interventional treatment was indicated in 141 accesses. In 115 of these 141 cases, intervention was performed using CO₂ fistulography alone. When the access flow stopped or decreased very much due to an occlusion and severe stenosis, we could not visualize the access by CO₂ fistulography, or could not perform CO₂ fistulography. For those cases, iodinated contrast fistulography was performed. When the vascular rupture, dissection, or clot formation occurred during intervention, iodinated contrast fistulography was performed. In three patients with arteriovenous fistula, manual injection of CO₂ into the brachial artery resulted in reflux of the gas into the thoracic aorta causing transient loss of consciousness.
Conclusion: CO₂ is a useful contrast agent in the diagnosis and intervention of failing hemodialysis access, eliminating or limiting the use of iodinated contrast material. Caution should be exercised to prevent CO₂ reflux into the aorta when injecting the gas into the brachial artery.