We evaluated the following outcomes in both groups : feasibility of the procedures , complications , surgical outcomes ( ankle-brachial index [ ABI ] ) , glomerular filtration rate using the Cockcroft-Gault formula , relationship between the volume of injected iodine and postoperative creatinine clearance , quality of the angiographic images obtained with CO2 , costs of the endovascular materials , and finally , cost of contrast agents .