Comparison between automated carbon dioxide digital angiography and standard iodinated contrast media angiography for lower limb arterial disease evaluation

Introduction: Carbon dioxide (CO2) has been validated as contrast agent in a large series of studies. Particular advantages of CO2 over iodinated contrast medium (ICM) are the absence of nephrotoxicity and allergic reactions. One of the limitations of CO2 angiography was the difficulty of CO2 manual injection due to its compressibility. Development of an automated CO2 injector has overcome these problems. Aim: it was to compare the feasibility, safety, and diagnostic accuracy of automated CO2 digital subtraction angiography (DSA) in comparison with ICM DSA in the evaluation of critical limb ischemic (CLI) patients. Methods: DSA with both CO2 and ICM, to directly compare the two techniques, was performed on 40 consecutive CLI patients. Sixteen females and 24 males participated in the study (mean age 71.7 years). We assessed the diagnostic accuracy of CO2 in identifying arterial stenosis in the lower limb with the ICM DSA used as the gold standard. Results: The overall diagnostic accuracy of CO2 DSA was 96.9% (sensitivity 99.0%; specificity 96.1%; PPV 91.1%; NPV 99.6%). Tolerable minor symptoms occurred in 3 patients. No allergic reactions and no significant decline in renal function were observed in patients receiving the CO2 injection. Conclusions: Carbon Dioxide DSA is a valuable and safe alternative to traditional ICM DSA for evaluating CLI patients. This modality should be considered as the standard choice for CLI patients undergoing angiographic evaluation, who are know to have renal insufficiency or contrast allergy.